WorldWideScience

Sample records for weldability

  1. Weldability of Additive Manufactured Stainless Steel

    Science.gov (United States)

    Matilainen, Ville-Pekka; Pekkarinen, Joonas; Salminen, Antti

    Part size in additive manufacturing is limited by the size of building area of AM equipment. Occasionally, larger constructions that AM machines are able to produce, are needed, and this creates demand for welding AM parts together. However there is very little information on welding of additive manufactured stainless steels. The aim of this study was to investigate the weldability aspects of AM material. In this study, comparison of the bead on plate welds between AM parts and sheet metal parts is done. Used material was 316L stainless steel, AM and sheet metal, and parts were welded with laser welding. Weld quality was evaluated visually from macroscopic images. Results show that there are certain differences in the welds in AM parts compared to the welds in sheet metal parts. Differences were found in penetration depths and in type of welding defects. Nevertheless, this study presents that laser welding is suitable process for welding AM parts.

  2. High Strength, Weldable Precipitation Aged Steels

    Science.gov (United States)

    Wilson, Alexander D.

    1987-03-01

    The family of plate steels represented by ASTM Specification A7101 is finding increasing applications. These low carbon, Cu-Ni-Cr-Mo-Cb, copper precipitation hardened steels have been identified by a number of designations over the years. During early development in the late 1960's and first commercial production in 1970, the steels were known as IN-787 (trademark of International Nickel Company).2 ASTM specifications were subsequently developed for structural (A710) and pressure vessel (A736) applications over ten years ago. More recent interest and application of this family of steels by the U.S. Navy has lead to development of a military specification MIL-S-24645 (SH),3 also initially known as "HSLA-80." Significant tonnage is being produced for the U.S. Navy as a replacement for HY80 (MIL-S-16216) in cruiser deck, bulkhead and hull applications.4 In these applications, the enhanced weldability and requirement of no preheat at this high strength and toughness level has been the main motivation for its use. Over the past 15 years, A710 type steels have also been used in a variety of applications, including off-shore platforms, pressure vessels, arctic linepipe valves and off-highway mining truck frames.

  3. Weldability and joining techniques for advanced fossil energy system alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P.; Liu, W.; Yang, D.; Zhou, G.; Morrison, M. [Univ. of Tennessee, Knoxville, TN (United States)

    1998-05-01

    The efforts represent the concerns for the basic understanding of the weldability and fabricability of the advanced high temperature alloys so necessary to affect increases in the efficiency of the next generation Fossil Energy Power Plants. The effort was divided into three tasks with the first effort dealing with the welding and fabrication behavior of 310HCbN (HR3C), the second task details the studies aimed at understanding the weldability of a newly developed 310TaN high temperature stainless (a modification of 310 stainless) and Task 3 addressed the cladding of austenitic tubing with Iron-Aluminide using the GTAW process. Task 1 consisted of microstructural studies on 310HCbN and the development of a Tube Weldability test which has applications to production welding techniques as well as laboratory weldability assessments. In addition, the evaluation of ex-service 310HCbN which showed fireside erosion and cracking at the attachment weld locations was conducted. Task 2 addressed the behavior of the newly developed 310 TaN modification of standard 310 stainless steel and showed that the weldability was excellent and that the sensitization potential was minimal for normal welding and fabrication conditions. The microstructural evolution during elevated temperature testing was characterized and the second phase particles evolved upon aging were identified. Task 3 details the investigation undertaken to clad 310HCbN tubing with Iron Aluminide and developed welding conditions necessary to provide a crack free cladding. The work showed that both a preheat and a post-heat was necessary for crack free deposits and the effect of a third element on the cracking potential was defined together with the effect of the aluminum level for optimum weldability.

  4. Weldability of Low Carbon Transformation Induced Plasticity Steel

    Institute of Scientific and Technical Information of China (English)

    ZHANG Mei; LI Lin; FU Ren-yu; ZHANG Ji-cheng; WAN Zi

    2008-01-01

    Transformation induced plasticity (TRIP) steel exhibited high or rather high carbon equivalent (CE) because of its chemical composition,which was a particularly detrimental factor affecting weldability of steels.Thus the weldability of a TRIP steel (grade 600) containing (in mass percent,%) 0.11C-1.19Si-1.67Mn was extensively studied.The mechanical properties and impact toughness of butt joint,the welding crack susceptibility of weld and heat affected zone (HAZ) for tee joint,control thermal severity (CTS) of the welded joint,and Y shape 60° butt joint were measured after the gas metal arc welding (GMAW) test.The tensile strength of the weld was higher than 700 Mpa.Both in the fusion zone (FZ) and HAZ for butt joint,the impact toughness was much higher than 27 J,either at room temperature or at -20 ℃,indicating good low temperature impact ductility of the weld of TRIP 600 steel.In addition,welding crack susceptibility tests revealed that weldments were free of surface crack and other imperfection.All experimental results of this steel showed fairly good weldability.For application,the crossmember in automobile made of this steel exhibited excellent weldability,and fatigue and durability tests were also accomplished for crossmember assembly.

  5. Weldability and Microstructure of Nickel-Silicon Based Alloys

    Institute of Scientific and Technical Information of China (English)

    LIU Qing-cai; LIU Yi; YANG Jian; J.W.Newkirk; ZHANG Shan-hong

    2006-01-01

    The NiSix based alloy typically has poor weldability due to its lower ductility. A limited amount of work has been performed on the weldability of NiSix based alloys. Therefore, the effect of heat treatment and welding parameters on weldability of the alloys, and the relationship between the weldability and microstructure were studied. The results show that the as-cast Ni-Si-Nb-B alloy (Ni 76.5%, Si 20%, Nb 3%, and B 0.5%) could be successfully welded after preheating at 600 ℃. The welding procedure should be performed on the alloys before any heat treatment and a preheating at 600 ℃ should be used. The fusion zone is harder than the matrix due to a large amount of γ phase and a finer microstructure. The cracks are predominantly intergranular in heat affected zone and associated with the needle-like γ phase. The heat treatment before welding increases the tendency of cracking in the fusion zone.

  6. Weldability and SAW welding wire of X80 pipeline steel

    Institute of Scientific and Technical Information of China (English)

    Huang Zhijun; Hu Lunji; Miao Kai; Zhang Xiaofeng; Chen Fu

    2006-01-01

    Weldability test was carried out on the newly developed fine grain, low sulphur, high strength and high toughness pipeline steel of X80 and its matching SA W wire. Test of maximum hardness in welding heat-affected zone and test of Y groove cracking show that X80 steel features low hardenability and good cracking resistance. The submerged arc welding joint made with the newly developed low carbon and multi-alloyed SA W wire of WGX2 exhibits a little higher strength than the base metal, qualified bending performance, under maximum limitation hardness and good impact toughness, which can completely meet the technical requirement of X80 steel. Despite somewhat coarsening the grain size in welding heat-affected zone is still much finer than that of traditional steels, and the microstructure in weld metal is almost full acicular ferrite. The results show that X80 steel and WGX2 wire are of great weldability.

  7. New approach for assessing the weldability of precipitation-strengthened nickel-base superalloys

    Institute of Scientific and Technical Information of China (English)

    Homam Naff akh Moosavy; Mohammad-Reza Aboutalebi; Seyed Hossein Seyedein; Meisam Khodabakhshi; Carlo Mapelli

    2013-01-01

    A new procedure was proposed for evaluating the weldability of nickel-base superalloys. The theory is on the basis of two microstructural patterns. In pattern I, the weld microstructure exhibits severe alloying segregation, many low-melting eutectic structures, and low weldability. The weld requires a weaker etchant and a shorter time for etching. In pattern II, the weld microstructure displays less alloying segregation, low quantity of eutectic structures, and high weldability. The weld needs a stronger etchant and a longer time for etching. Five superalloys containing diff erent amounts of Nb and Ti were designed to verify the patterns. After welding operations, the welds were etched by four etchants with diff erent corrosivities. The weldability was determined by TG-DSC measurements. The metallography and weldability results confirmed the theoretic patterns. Finally, the etchant corrosivity and etching time were proposed as new criteria to evaluate the weldability of nickel-base superalloys.

  8. New approach for assessing the weldability of precipitation-strengthened nickel-base superalloys

    Science.gov (United States)

    Moosavy, Homam Naffakh; Aboutalebi, Mohammad-Reza; Seyedein, Seyed Hossein; Khodabakhshi, Meisam; Mapelli, Carlo

    2013-12-01

    A new procedure was proposed for evaluating the weldability of nickel-base superalloys. The theory is on the basis of two microstructural patterns. In pattern I, the weld microstructure exhibits severe alloying segregation, many low-melting eutectic structures, and low weldability. The weld requires a weaker etchant and a shorter time for etching. In pattern II, the weld microstructure displays less alloying segregation, low quantity of eutectic structures, and high weldability. The weld needs a stronger etchant and a longer time for etching. Five superalloys containing different amounts of Nb and Ti were designed to verify the patterns. After welding operations, the welds were etched by four etchants with different corrosivities. The weldability was determined by TG-DSC measurements. The metallography and weldability results confirmed the theoretic patterns. Finally, the etchant corrosivity and etching time were proposed as new criteria to evaluate the weldability of nickel-base superalloys.

  9. Weldability investigation of fine-grained S1100QL steel

    Directory of Open Access Journals (Sweden)

    I. Samardžić

    2016-07-01

    Full Text Available This paper presents the results of weldability investigation on welded joints made of fine - grained high-strength S1100QL steel. The investigations are performed on two welded plates by HV 10 hardness measuring and by Charpy V notch testing at different test temperatures. Mechanical properties of welded joints are overviewed, along with welded parameters, all of which enable obtaining of high-quality welded joints.

  10. Development of weldable, corrosion-resistant iron-aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, P.J.; Goodwin, G.M.; Wang, X.L. [Oak Ridge National Laboratory, TN (United States)

    1995-05-01

    Corrosion-resistant, weldable FeAl alloys have been developed with improved high-temperature strength industrial applications. Previous processing difficulties with these alloys led to their evaluation as weld-overlay claddings on conventional structural steels to take advantage of their good properties now. Simplified and better processing methods for monolithic FeAl components are also currently being developed so that components for industrial testing can be made. Other avenues for producing FeAl coatings are currently being explored. Neutron scattering experiments residual stress distributions in the FeAl weld-overlay cladding began in FY 1993 and continued this year.

  11. Microstructural and weldability evaluation of 310TaN

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P. [Univ. of Tennessee, Knoxville, TN (United States); Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    Excellent weldability and good microstructural stability of 310TaN, in terms of the formation and growth of secondary phases at elevated temperature, was revealed in this investigation. The interganular stress corrosion resistance of 310TaN is superior to modified 800H and 310HCbN evaluated previously due to the fact that TaC, TaN and Ta(C,N) particles are more stable compared to Nb-rich or Ti-rich carbides, nitrides and carbonitrides presented in the other advanced alloys. Using resistance spot welding technique for which extremely fast cooling is a characteristic, it was found that a very minor amount of gain boundary liquation takes place during welding thermal cycling. The limited grain boundary liquation is of the eutectic type i.e., a low tendency to weld HAZ hot cracking.

  12. Effect of mechanical restraint on weldability of reduced activation ferritic/martensitic steel thick plates

    Energy Technology Data Exchange (ETDEWEB)

    Serizawa, Hisashi, E-mail: serizawa@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Nakamura, Shinichiro [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suite, Osaka 565-0871 (Japan); Tanaka, Manabu; Kawahito, Yousuke [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Tanigawa, Hiroyasu [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 2-4 Shirakita, Shirane, Naka, Ibaraki 319-1195 (Japan); Katayama, Seiji [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2011-10-01

    As one of the reduced activation ferritic/martensitic steels, the weldability of thick F82H plate was experimentally examined using new heat sources in order to minimize the total heat input energy in comparison with TIG welding. A full penetration of 32 mm thick plate could be produced as a combination of a 12 mm deep first layer generated by a 10 kW fiber laser beam and upper layers deposited by a plasma MIG hybrid welding with Ar + 2%O shielding gas. Also, the effect of mechanical restraint on the weldability under EB welding of thick F82H plate was studied by using FEM to select an appropriate specimen size for the basic test. The appropriate and minimum size for the basic test of weldability under EB welding of 90 mm thick plate might be 200 mm in length and 400 mm in width where the welding length should be about 180 mm.

  13. Review of the weldability window concept and equations for explosive welding

    Science.gov (United States)

    Ribeiro, J. B.; Mendes, R.; Loureiro, A.

    2014-05-01

    Explosive cladding/welding is usually considered a solid state process in which the detonation of a certain amount of an explosive composition is used to accelerate one of the materials to be weld against the other in order to promote a high velocity oblique collision that will be responsible for bonding the materials. The conditions that should be met to achieve good welds define what is called as a weldability window or criteria. A weldability criteria based on the collision point velocity (Vc) and on the collision angle (β) is the most used today. In the β-Vc space the weldability window is defined by four lines or limits. Despite of its wide used in explosive welding works, neither the concepts behind those limits neither the equations used to define them in the β-Vc space are particularly clear. Contradictory concepts, and equations with undefined variables or parameters, are commonly found in the literature. This paper aims to clarify those concepts and equations through an integrated description of the weldability limits and a reviewed presentation of the associated equations with the variables and parameters, including their units, clearly defined. The reviewed concepts and equations are then used for the description of the explosive weld of stainless steel to carbon steel in cylindrical configuration.

  14. Development of WELDABLE12CR stainless steel seamless pipe with superior weldability and corrosion resistance for linepipe application; Yosetsusei oyobi taishokusei ni sugureta linepipe yo stainless keimokumukokan WELDABLE12CR no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Y.; Kimura, M.; Toyooka, T.; Nakano, Y.; Murase, F. [Kawasaki Steel Corp., Tokyo (Japan)

    1998-06-20

    Severe corrosive circumstance of oil wells and gas wells including high temperature, high CO2 partial pressure, high chlorine ion concentration, and further H2S are becoming more and more serious in recent years. Measures to prevent CO2 corrosion and sulfide stress crack are necessary for pipelines called flowlines and gathering line for transporting oil or gas which has severe corrosivity before treatment. WELDABLE12CR steel pipe which is seamless martensite stainless steel with excellent weldability and corrosion resistance is developed by the present authors. There two kinds of such steel pipes, one is 11Cr steel (0.01C-11Cr-1.5Ni-0.5Cu-0.01N-based steel) that is superior in corrosion resistance to 13Cr steel for oil well so that it can be used in CO2 circumstance, and the other one is 12Cr steel (0.01C-12Cr-5Ni-2Mo-0.01N-based steel) that has excellent SSC-resistance thus being used in the circumstance containing CO2 and a trace quantity of H2S. 5 refs., 4 figs., 3 tabs.

  15. Cryogenic Treatment of Al-Li Alloys for Improved Weldability, Repairability, and Reduction of Residual Stresses

    Science.gov (United States)

    Malone, Tina W.; Graham, Benny F.; Gentz, Steven J. (Technical Monitor)

    2001-01-01

    Service performance has shown that cryogenic treatment of some metals provides improved strength, fatigue life, and wear resistance to the processed material. Effects such as these were initially discovered by NASA engineers while evaluating spacecraft that had returned from the cold vacuum of space. Factors such as high cost, poor repairability, and poor machinability are currently prohibitive for wide range use of some aerospace aluminum alloys. Application of a cryogenic treatment process to these alloys is expected provide improvements in weldability and weld properties coupled with a reduction in repairs resulting in a significant reduction in the cost to manufacture and life cycle cost of aerospace hardware. The primary purpose of this effort was to evaluate the effects of deep cryogenic treatment of some aluminum alloy plate products, welds, and weld repairs, and optimize a process for the treatment of these materials. The optimized process is being evaluated for improvements in properties of plate and welds, improvements in weldability and repairability of treated materials, and as an alternative technique for the reduction of residual stresses in repaired welds. This paper will present the results of testing and evaluation conducted in this effort. These results will include assessments of changes in strength, toughness, stress corrosion susceptability, weldability, repairability, and reduction in residual stresses of repaired welds.

  16. Weldability with Process Parameters During Fiber Laser Welding of a Titanium Plate (II) - The Effect of Control of Heat Input on Weldability -

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Do; Kim, Ji Sung [Korea Maritime and Ocean Univ., Busan (Korea, Republic of)

    2016-12-15

    Laser welding is a high-density energy welding method. Hence, deep penetration and high welding speed can be realized with lower heat input as compared with conventional welding. The heat input of a CW laser welding is determined by laser power and welding speed. In this study, bead and lap welding of 0.5 mmt pure titanium was performed using a fiber laser. Its weldability with laser power and welding speed was evaluated. Penetration, bead width, joining length, and bead shape were investigated, and the mechanical properties were examined through tensile-shear strength tests. Welds with sound joining length were obtained when the laser power and welding speed were respectively 0.5 kW and 2.5 m/min, and 1.5 kW and 6 m/min, and the weld obtained at low output presented better ductility than that obtained at high output.

  17. Properties, weldability and corrosion behavior of supermartensitic stainless steels for on- and offshore applications

    Energy Technology Data Exchange (ETDEWEB)

    Taban, Emel; Kaluc, Erdinc; Ojo, Olatunji Oladimeji [Kocaeli Univ. (Turkey). Welding Research, Education and Training Center

    2016-08-01

    Stimulated material-environment interactions inside and around flowlines of deep or ultra deep wells during oil and gas exploration, and fabrication economy of pipelines have been the major challenges facing the oil and gas industries. Presumably, an extensive focus on high integrity, performance and material economy of flowlines have realistically made supermartensitic stainless steels (SMSS) efficient and effective material choices for fabricating onshore and offshore pipelines. Supermartensitic stainless steels exhibit high strength, good low temperature toughness, sufficient corrosion resistance in sweet and mildly sour environments, and good quality weldability with both conventional welding processes and modern welding methods such as laser beam welding, electron beam welding and hybrid welding approaches. In terms of economy, supermartensitic stainless steels are cheaper and they are major replacements for more expensive duplex stainless steels required for tubing applications in the oil and gas industry. However, weld areas of SMSS pipes are exposed to sulphide stress cracking (SSC), so intergranular stress corrosion cracking (IGSCC) or stress corrosion cracking can occur. In order to circumvent this risk of cracking, a post-weld heat treatment (PWHT) for 5 minutes at about 650 C is recommended. This paper provides detailed literature perusal on supermartensitic stainless steels, their weldability and corrosion behaviors. It also highlights a major research area that has not been thoroughly expounded in literature; fatigue loading behaviors of welded SMSS under different corrosive environments have not been thoroughly detailed in literature.

  18. THE EFFECT OF BORON AND CARBON ADDITION ON WELDABILITY OF DS TMS-75 SUPERALLOY

    Institute of Scientific and Technical Information of China (English)

    M.C.Chaturvedi; Y.L.Wang; N.L.Richards

    2005-01-01

    Four alloys TMS-75 (Base), Base+B, Base+C and TMD-103 (Base+B+C) with varying levels of B, C were directionally solidified (DS), and their weldability was investigated by bead-onplate electron beam welding.It was found that cracking occurred in the weld-metal, as well as in the heat affected zone (HAZ).Both γ/γ' and/or γ/carbide eutectic contributed to the weld-metal cracking, and the γ/γ' eutectic was found to be mainly responsible for cracking in HAZ However, constitutional liquation of carbides seems to have made some contribution also.The B addition had a detrimental effect on HAZ cracking susceptibility, while C addition improved it appreciably even in the presence of B.In addition, no obvious differences were observed in cracking susceptibility of weld-metal in the four alloys.The cracking modes and mechanisms underlying the effect of B and C addition on weldability could be explained on the basis of microstructures of the four alloys.

  19. Weldability and Monitoring of Resistance Spot Welding of Q&P and TRIP Steels

    Directory of Open Access Journals (Sweden)

    Pasquale Russo Spena

    2016-11-01

    Full Text Available This work aims at investigating the spot weldability of a new advanced Quenching and Partitioning (Q&P steel and a Transformation Induced Plasticity (TRIP steel for automotive applications by evaluating the effects of the main welding parameters on the mechanical performance of their dissimilar spot welds. The welding current, the electrode tip voltage and the electrical resistance of sheet stack were monitored in order to detect any metal expulsion and to evaluate its severity, as well as to clarify its effect on spot strength. The joint strength was assessed by means of shear and cross tension tests. The corresponding fracture modes were determined through optical microscopy. The welding current is the main process parameter that affects the weld strength, followed by the clamping force and welding time. Metal expulsion can occur through a single large expulsion or multiple expulsions, whose effects on the shear and cross tension strength have been assessed. Longer welding times can limit the negative effect of an expulsion if it occurs in the first part of the joining process. The spot welds exhibit different fracture modes according to their strengths. Overall, a proper weldability window for the selected process parameters has been determined to obtain sound joints.

  20. Aluminum alloy weldability. Identification of weld solidification cracking mechanisms through novel experimental technique and model development

    Energy Technology Data Exchange (ETDEWEB)

    Coniglio, Nicolas

    2008-07-01

    The objective of the present thesis is to make advancements in understanding solidification crack formation in aluminum welds, by investigating in particular the aluminum 6060/4043 system. Alloy 6060 is typical of a family of Al-Mg-Si extrusion alloys, which are considered weldable only when using an appropriate filler alloy such as 4043 (Al-5Si). The effect of 4043 filler dilution (i.e. weld metal silicon content) on cracking sensitivity and solidification path of Alloy 6060 welds are investigated. Afterwards, cracking models are developed to propose mechanisms for solidification crack initiation and growth. Cracking Sensitivity. Building upon the concept that silicon improves weldability and that weldability can be defined by a critical strain rate, strain rate-composition combinations required for solidification crack formation in the Al- 6060/4043 system were determined using the newly developed Controlled Tensile Weldability (CTW) test utilizing local strain extensometer measurements. Results, presented in a critical strain rate - dilution map, show a crack - no crack boundary which reveals that higher local strain rates require higher 4043 filler dilution to avoid solidification cracking when arc welding Alloy 6060. Using the established crack - no crack boundary as a line of reference, additional parameters were examined and their influence on cracking characterized. These parameter influences have included studies of weld travel speed, weld pool contaminants (Fe, O, and H), and grain refiner additions (TiAl{sub 3} + Boron). Each parameter has been independently varied and its effect on cracking susceptibility quantified in terms of strain rate - composition combinations. Solidification Path. Solidification path of the Al-6060/4043 system was characterized using thermal analysis and phase identification. Increasing 4043 filler dilution from 0 to 16% in Alloy 6060 arc welds resulted in little effect on thermal arrests and microstructure, no effect on

  1. Weldability with Process Parameters During Fiber Laser Welding of a Titanium Plate (I) - Effect of Type and Flow Rate of Shielding Gases on Weldability -

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Do; Kim, Ji Sung [Korea Maritime and Ocean Univ., Busan (Korea, Republic of)

    2016-12-15

    In this study, welding of pure titanium was carried out by using a continuous wave fiber laser with a maximum output of 6.3 kW. Because brittle regions form easily in titanium as a result of oxidation or nitriding, the weld must be protected from the atmosphere by using an appropriate shielding gas. Experiments were performed by changing the type and the flow rate of shielding gases to obtain the optimal shielding condition, and the weldability was then evaluated. The degree of oxidation and nitriding was distinguished by observing the color of beads, and weld microstructure was observed by using an optical microscope and a scanning electron microscope. The mechanical properties of the weld were examined by measuring hardness. When the weld was oxidized or nitrified, the bead color was gray or yellow, and the oxygen or nitrogen content in the bead surface and overall weld tended to be high, as a result of which the hardness of the weld was thrice that of the base metal. A sound silvery white bead was obtained by using Ar as the shielding gas.

  2. Weldability of reduced activation ferritic/martensitic steel under ultra power density fiber laser welding

    Energy Technology Data Exchange (ETDEWEB)

    Serizawa, H.; Kawahito, Y.; Katayama, S. [Osaka Univ., Joining and Welding research Institute, Ibaraki (Japan); Ogiwara, H.; Tanigawa, H. [Japan Atomic Energy Agency, Ibaraki-ken (Japan)

    2007-07-01

    Full text of publication follows: Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems as it has been developed based on massive industrial experience of ferritic/martensitic steel replacing Mo and Nb of high chromium heat resistant martensitic steels (such as modified 9Cr-1Mo) with W and Ta, respectively. As one of RAFMS, F82H, which has been developed and studied in Japan, is designed with emphasis on high temperature property and weldablility, and was provided and evaluated in various countries as a part of the collaboration of IEA fusion materials development. Although F82H is the well perceived RAFM as ITER Test Blanket Module (TBM) structural material, the weldability was proved though TIG, EB and YAG laser weld tests using only 15 and 25 mm thickness plate. In order to reduce the welding distortion, the residual stress and the area of the heat affected zone, it is necessary to decrease the total heat input under the welding. Recently, as a result of R and D efforts about the sources of laser beam, a high-power fiber laser beam has been developed as one of the desirable heat sources for high-speed and deep-penetration welding. Since the power density of the fiber laser beam is very large, it is possible to increase the welding speed more than 10 m/min. So, in this study, the weldability of 1.5 mm thickness F82H plate and pipe was examined by using a ultra power density fiber laser, in order to reveal the excellent weldability of F82H. As a basic study of the butt welding between 1.5 mm plate and 1.5 mm thickness pipe with 11 mm outer diameter, the focus position, the beam position and the laser power were varied using 25 mm square plate and 25 mm length pipe. Then, by using the fiber laser with 1.1 MW/mm{sup 2} peak power density under the appropriate welding condition obtained from the basic study, a full penetrated weld bead with narrow width was formed in the butt

  3. Martensitic stainless steel seamless linepipe with superior weldability and CO{sub 2} corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Y.; Kimura, M.; Koseki, T.; Toyooka, T.; Murase, F. [Kawasaki Steel Corp., Handa, Aichi (Japan)

    1997-08-01

    Two types of new martensitic stainless steel with good weldability and superior corrosion resistance have been developed for line pipe application. Both steels are suitable for welding without preheating owing to lowering C and N contents, and they show good low temperature toughness in welds without PWHT. One is applied to sweet environments. It gives better resistance to CO{sub 2} corrosion than the 13Cr martensitic stainless steel for OCTG. Lowering C and addition of Ni contribute to reduction of general corrosion rate in the CO{sub 2} environment. The addition of Cu improves the pitting resistance. The other is applied to light sour environments. It gives good SSC resistance in welds owing to the improvement of the pitting resistance due to Mo addition. The seamless pipes of these martensitic stainless steels are applicable as substitutes for a part of duplex stainless steel flow lines.

  4. Comparative study of TIG and SMAW root welding passes on ductile iron cast weldability

    Directory of Open Access Journals (Sweden)

    J. Cárcel-Carrasco

    2017-01-01

    Full Text Available This work compares the weldability of ductile iron when: (I a root weld is applied with a tungsten inert gas (TIG process using an Inconel 625 source rod and filler welds are subsequently applied using coated electrodes with 97,6%Ni; and (II welds on ductile iron exclusively made using the manual shielded metal arc welding technique (SMAW. Both types of welds are performed on ductile iron specimen test plates that are subjected to preheat and post-weld annealing treatments. Samples with TIG root-welding pass shown higher hardness but slightly lower ductility and strength. Both types of welding achieved better ductile and strength properties than ones found in literature.

  5. Effect of Al coating conditions on laser weldability of Al coated steel sheet

    Institute of Scientific and Technical Information of China (English)

    Jung-Han LEE; Jong-Do KIM; Jin-Seok OH; Seo-Jeong PARK

    2009-01-01

    Al coated steel sheets with excellent heat resistance, thermal reflection, and corrosion resistance are widely used in various applications. The laser weldability of the Al coated steel sheet for full penetration welding was reported. The phenomenon caused by intermixed aluminum and behavior of aluminum in the weld were investigated. Al coated steel sheets that have various thickness and coating mass were prepared for laser welding. The effects of parameters such as welding conditions and Al coating conditions were investigated. Al content mixed in the weld after laser welding was evaluated, and then a correlation between the mixed Al and mechanical properties was investigated. The results show that the Al-rich zones which have Fe-Al intermetallic compounds are found in the weld. The intermetallic compounds cause the decreased strength of the weld.

  6. Variable amplitude corrosion fatigue and fracture mechanics of weldable high strength jack-up steels

    Science.gov (United States)

    Etube, Linus Sone

    The tubular welded joints used in the construction of Offshore structures can experience millions of variable amplitude wave induced stress cycles during their operational life. Fatigue has been identified as the main cause of degradation of structural integrity in these structures. As a result, fatigue is an important consideration in their design. Jack-up legs are made from a range of high strength steels with yield strengths up to TOOMPa. These steels are thought to exhibit fatigue resistance properties which are different when compared with conventional fixed platform steels such as BS 4360 50D and BS 7191 355D. The difference in their behaviour was heightened by the discovery, in the late 80s and early 90s, of extensive cracking around the spud can regions of several Jack-ups operating in the North Sea. It was thought that these steels may be more susceptible to hydrogen cracking and embrittlement. There was the additional requirement to study their behaviour under realistic loading conditions typical of the North Sea environment. This thesis contains results of an investigation undertaken to assess the performance of a typical high strength weldable Jack-up steel under realistic loading and environmental conditions. Details of the methodology employed to develop a typical Jack-up Offshore Standard load History (JOSH) are presented. The factors which influence fatigue resistance of structural steels used in the construction of Jack-up structures are highlighted. The methods used to model the relevant factors for inclusion in JOSH are presented with particular emphasis on loading and structural response interaction. Results and details of experimental variable amplitude corrosion fatigue (VACF) tests conducted using JOSH are reported and discussed with respect to crack growth mechanisms in high strength weldable Jack-up steels. Different fracture mechanics models for VACF crack growth prediction are compared and an improved generalised methodology for fast

  7. Effect of Nitrogen Shielding Gas on Laser Weldability of Austenitic Stainless Steel

    Science.gov (United States)

    Katayama, Seiji; Yoshida, Daisuke; Matsunawa, Akira

    YAG and CO2 laser weldability of Type 304 steel in nitrogen (N2) shielding gas was evaluated by investigating melting characteristics, porosity formation tendency, N content, microstructural characteristics and cracking sensitivity. Melting characteristics of weld beads produced below 4 kW were not so much different between YAG and CO2 laser. Porosity was remarkably reduced in any welds produced with nitrogen gas in comparison with normal welds made with Ar or He gas. This was attributed to the decrease in N content in a keyhole due to the reaction with evaporated Cr vapor as well as the absorption in the keyhole molten surface. The N contents absorbed in Type 304 weld fusion zones were larger under any welding conditions with CO2 laser than with YAG laser. On the other hand, in the case of several CO2 laser weld metals, solidification cracks occurred along the grain boundaries of a fully austenitic phase. Primary solidification of delta-ferrite phase normally took place in Type 304 weld metals, but a primary austenite phase was formed owing to the N enrichment, and micro-segregation of P and S increased along the grain boundaries. Consequently, cracking was induced by enhancement of cracking sensitivity due to a wider BTR. It was concluded that a great effect of nitrogen on the weldability of stainless steel was noted more remarkably in CO2 laser weld fusion zones than in YAG laser ones. It must be attributed to the N plasma formation leading to higher temperatures and consequent generation of more active N during CO2 laser welding.

  8. Weldability of 780 MPa Super-High Strength Heavy-Duty Truck Crossbeam Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-nan; DI Hong-shuang; ZHANG Chit; DU Lin-xiu; DONG Xue-xir

    2012-01-01

    CO2-shielded welding experiments of newly developed, 780 MPa super-high strength heavy-duty truck crossbeam steel were conducted, and the microstructure, microhardness, mechanical properties, and impact tough- hess of the welded joint were studied. The evolution of the microstructure of the welded joint occurred as follows.. welding seam (acicular ferrite+proeutectoid ferrite)→fusion zone (granular bainite-long strip M/A island)→coarse grain zone (granular bainite-long strip or short bar M/A island)→fine grain zone (ferrite+ pearlite+ blocky M/A is- land)→mixed grained zone (ferrite+granular bainite+blocky M/A island)→base metal (proeutectoid ferrite+gran- ular bainite-hlocky or granular M/A island). Increasing the density of the grain boundaries can effectively improve the impact toughness, and the blocky M/A island hindered crack propagation more effectively than the long strip M/A island. The new hot-rolled 780 MPa super-high strength steel had excellent weldability. The welding technology was applied under the following conditions: welding voltage was 20 to 21 V, welding current was 200 to 210 A, and the gas flow rate was 25 L/rain.

  9. Weldability of the superalloys Haynes 188 and Hastelloy X by Nd:YAG

    Directory of Open Access Journals (Sweden)

    Graneix Jérémie

    2014-01-01

    Full Text Available The requirements for welded aircraft parts have become increasingly severe, especially in terms of the reproducibility of the geometry and metallurgical grade of the weld bead. Laser welding is a viable method of assembly to meet these new demands, because of automation, to replace the manual TIG welding process. The purpose of this study is to determine the weldability of Hastelloy X and Haynes 188 alloys by the butt welding process with a Nd:YAG laser. To identify the influential parameters of the welding process (laser power, feed rate, focal diameter and flow of gas while streamlining testing, an experimental design was established with the CORICO software using the graphic correlation method. The position of the focal point was fixed at 1/3 of the thickness of the sheet. The gas flow rate and the power of the beam have a major effect on the mechanical properties and geometry of the weld. The strength of the weld is comparable to that of the base metal. However, there is a significant decrease in the elongation at break of approximately 30%. The first observations of the cross section of the weld by scanning electron microscopy coupled with EBSD analysis show a molten zone presenting dendritic large grains compared to the equiaxed grains of the base metals without a heat affected zone.

  10. Friction Stir Weldabilities of AA1050-H24 and AA6061-T6 Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Huijie LIU; Hidetoshi FUJIN; Masakatsu MAEDA; Kiyoshi NOGI

    2005-01-01

    The friction stir weldabilities of the strain-hardened AA1050-H24 and precipitate-hardened AA6061-T6 aluminum alloys were examined to reveal the effects of material properties on the friction stir welding behavior. The experimental results are obtlained. (1) For AA1050-H24, the weld can possess smoother surface ripples; there is no elliptical weld nugget in the weld; there is no discernible interface between the stir zone and the thermomechanically affected zone;and the internal defect of the weld looks like a long crack and is located in the lower part of the weld. (2) For AA6061-T6, the weld usually possesses slightly rougher surface ripples; an elliptical weld nugget clearly exists in the weld; there are discernible interfaces among the weld nugget, thermomechanically affected zone and heat affected zone; and the internal defect of the weld is similar to that of the AA1050-H24 weld. (3) The effective range of welding parameters for AA1050-H24 is narrow, while the one for AA6061-T6 is very wide. (4) The maximum tensile strength efficiency of the AA1050-H24 joints is similar to that of the AA6061-T6 joints, i.e. 79% and 77%, respectively.

  11. Resistance spot weldability of lightweight steel with a high Al content

    Science.gov (United States)

    Hwang, Insung; Kim, Dongcheol; Kang, Munjin; Kwak, Jae-Hyun; Kim, Young-Min

    2017-03-01

    Using alternating current (AC)- and direct current (DC)-type welders, the resistance spot weldability of lightweight steel was evaluated under various electrode forces, welding currents, and times. The acceptable welding conditions were specified; however, these had very narrow ranges and there was little difference between the conditions determined for the AC- and DC-type welding. In both types of welding with electrode forces of of 300 kgf and 400 kgf, the acceptable weld currents were 5.0 kA and 5.5 kA, respectively. Also, the nugget size increased with the welding current. Under the acceptable welding conditions, there were no significant changes in the maximum tensile shear strength and nugget size, as 6.4-6.6 kN and 4.1-4.3 mm, respectively. The microstructure of weld metals was consisted of martensite, austenite and ferrite. And the small fraction of martensite was founded in the heat affected zone (HAZ), therefore the weld metal had the greatest hardness, and HAZ softening did not occur in this study. Considering the fracture surface, cleavage and ductile fracture were investigated because of the existence of martensite and ferrite in the welds.

  12. Development of weldable, corrosion-resistant iron-aluminide (FeAl) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, P.J.; Goodwin, G.M.; Wang, X.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    A boron-microalloyed FeAl alloy (Fe-36Al-0.2Mo-0.05Zr-0.13C, at.%, with 100-400 appm B) with improved weldability and mechanical properties was developed in FY 1994. A new scale-up and industry technology development phase for this work began in FY 1995, pursuing two parallel paths. One path was developing monolithic FeAl component and application technology, and the other was developing coating/cladding technology for alloy steels, stainless steels and other Fe-Cr-Ni alloys. In FY 1995, it was found that cast FeAl alloys had good strength at 700-750{degrees}C, and some (2.5%) ductility in air at room-temperature. Hot-extruded FeAl with refined grain size was found to have ductility and to also have good impact-toughness at room-temperature. Further, it was discovered that powder-metallurgy (P/M) FeAl, consolidated by direct hot-extrusion at 950-1000{degrees}C to have an ultra fine-grained microstructure, had the highest ductility, strength and impact-toughness ever seen in such intermetallic alloys.

  13. A study of weldability and fracture modes in electron beam weldments of AZ series magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chi, C.-T. [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan (China) and System Manufacturing Center, Chung-Shan Institute of Science and Technology, PO Box 90008-14, Sanxia 237, Taipei, Taiwan (China)]. E-mail: joseph.mse92g@nctu.edu.tw; Chao, C.-G. [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan (China)]. E-mail: c_g_chao@hotmail.com; Liu, T.-F. [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan (China)]. E-mail: coe@cc.nctu.edu.tw; Wang, C.-C. [Graduate School of Industrial Design and Architecture, Shih-Chien University, Taipei 104, Taiwan (China)]. E-mail: zcwang@mail.usc.edu.tw

    2006-11-05

    Given the growing need for environmental protection and lightweight construction, electron beam welding (EBW) is becoming the most important welding technology because it can compensate for the poor formability of magnesium alloys. This paper examines interactions between the properties of three AZ series magnesium alloys and welding conditions. The EBW process can yield four kinds of defect in a weld: cavities, the heat-affected zone (HAZ), undercuts, and root concavities. These defects obviously induce stress concentrations in the weld, and may seriously damage its strength. Additionally, the distribution of precipitates ({gamma} phase, Mg{sub 17}Al{sub 12}) in the fusion zone (FZ) changes from a relatively small number of scattered particles to a dense population of dendrites as the Al content of the magnesium alloy increases. Under excessive tensile stress, alloy weldments break in one of two fracture modes: an irregular FZ fracture, or a regular HAZ fracture. AZ31B usually exhibits the former mode and AZ91D the latter, while AZ61A exhibits each mode half the time. The overall weldability, which depends on the random distribution of these precipitates and defects, is found to be greatest for the AZ61A alloy. The best process window, on the other hand, is found for the AZ91D alloy. Finally, we obtain optimum parameters for the EBW process and empirical formulae for the weldment strength as a function of these parameters. These results are closely related to each other.

  14. Weldability Evaluation of a Cu-Bearing High-Strength Blast-Resistant Steel

    Science.gov (United States)

    Caron, Jeremy L.; Babu, Sudarsanam Suresh; Lippold, John C.

    2011-12-01

    BlastAlloy160 (BA-160) steel, with a nominal composition of Fe-0.05C-3.65Cu-6.5Ni-1.84Cr-0.6Mo-0.1V (wt pct), is strengthened by Cu-rich precipitates and M2C carbides. This alloy was subjected to several weldability tests to assess its susceptibility to certain weld cracking mechanisms. Hot ductility testing revealed a liquation cracking temperature range (LCTR) of 148 K (-125 °C), which suggested moderate susceptibility to heat-affected zone (HAZ) liquation cracking. The enrichment of Ni and Cu was measured along the prior austenite grain boundaries in the simulated partially melted zone (PMZ) and was consistent with similar enrichment at interdendritic boundaries of the simulated fusion zone (FZ). Good wetting and penetration of liquid films along the austenite grain boundaries of the PMZ was also observed. Associated with that finding were thermodynamic calculations indicating a completely austenitic (face-centered cubic) microstructure at elevated temperatures. In testing to determine reheat cracking susceptibility, ductility values of 41 to 78 pct RA were established for the 723 K to 973 K (450 °C to 700 °C) temperature range. The good ductility values precluded susceptibility to reheat cracking according to the test criterion. Dilatometric measurements and thermodynamic calculations revealed the formation of austenite in the reheat cracking temperature range, which was attributed to the high Ni content of the BA-160 alloy.

  15. Preliminary Results on FeCrAl Alloys in the As-received and Welded State Designed to Have Enhanced Weldability and Radiation Tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hu, Xunxiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-30

    The present report summarizes and discusses the recent results on developing a modern, nuclear grade FeCrAl alloy designed to have enhanced radiation tolerance and weldability. The alloys used for these investigations are modern FeCrAl alloys based on a Fe-13Cr-5Al-2Mo-0.2Si-0.05Y alloy (in wt.%, designated C35M). Development efforts have focused on assessing the influence of chemistry and microstructure on the fabricability and performance of these newly developed alloys. Specific focus was made to assess the weldability, thermal stability, and radiation tolerance.

  16. Grain Growth Behavior, Tensile Impact Ductility, and Weldability of Cerium-Doped Iridium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    McKamey, C.G.

    2002-05-28

    An iridium alloy doped with small amounts of cerium and thorium is being developed as a potential replacement for the iridium-based DOP-26 alloy (doped with thorium only) that is currently used by the National Aeronautics and Space Administration (NASA) for cladding and post-impact containment of the radioactive fuel in radioisotope thermoelectric generator (RTG) heat sources which provide electric power for interplanetary spacecraft. This report summarizes results of studies conducted to date under the Iridium Alloy Characterization and Development subtask of the Radioisotope Power System Materials Production and Technology Program to characterize the properties of the iridium-based alloy (designated as DOP-40) containing both cerium and thorium. Included within this report are data on grain growth of sheet material in vacuum and low-pressure oxygen environments, grain growth in vacuum of the clad vent set cup material, weldability, and the effect of grain size and test temperature on tensile properties. Where applicable, data for the DOP-26 alloy are included for comparison. Both grain size and grain-boundary cohesion affect the ductility of iridium alloys. In this study it was found that cerium and thorium, when added together, refine grain size more effectively than when thorium is added by itself (especially at high temperatures). In addition, the effect of cerium additions on grain-boundary cohesion is similar to that of thorium. Mechanical testing at both low ({approx} 10{sup -3}s{sup -1}) and high ({approx} 10{sup -3}s{sup -1}) strain rates showed that the Ce/Th-doped alloys have tensile ductilities that are as good or better than the DOP-26 alloy. The general conclusion from these studies is that cerium can be used to replace some of the radioactive thorium currently used in DOP-26 while maintaining or improving its metallurgical properties. The current DOP-26 alloy meets all requirements for cladding the radioactive fuel in the RTG heat source, but the

  17. Laser Weldability of High-Strength Al-Zn Alloys and Its Improvement by the Use of an Appropriate Filler Material

    Science.gov (United States)

    Enz, Josephin; Riekehr, Stefan; Ventzke, Volker; Huber, Norbert; Kashaev, Nikolai

    2016-06-01

    Heat-treatable Al-Zn alloys are promising candidates for use as structural lightweight materials in automotive and aircraft applications. This is mainly due to their high strength-to-density ratio in comparison to conventionally employed Al alloys. Laser beam welding is an efficient method for producing joints with high weld quality and has been established in the industry for many years. However, it is well known that aluminum alloys with a high Zn content or, more precisely, with a high (Zn + Mg + Cu) content are difficult to fusion weld due to the formation of porosity and hot cracks. The present study concerns the laser weldability of these hard-to-weld Al-Zn alloys. In order to improve weldability, it was first necessary to understand the reasons for weldability problems and to identify crucial influencing factors. Based on this knowledge, it was finally possible to develop an appropriate approach. For this purpose, vanadium was selected as additional filler material. Vanadium exhibits favorable thermophysical properties and, thereby, can improve the weldability of Al-Zn alloys. The effectiveness of the approach was verified by its application to several Al-Zn alloys with differing amounts of (Zn + Mg + Cu).

  18. Investigation of the weldability of iron-aluminum-chromium overlay coatings for corrosion protection in oxidizing/sulfidizing environments

    Science.gov (United States)

    Regina, Jonathan R.

    The current study investigated the effect of chromium additions on the hydrogen cracking susceptibility of Fe-Al weld overlay claddings containing chromium additions. It was found that the weldability of FeAlCr claddings was a function of both the aluminum and chromium concentrations of the weld coatings. Weld overlay compositions that were not susceptible to hydrogen cracking were identified and the underlying mechanism behind the hydrogen cracking phenomenon was investigated further. It was concluded that the cracking behavior of the FeAlCr welds depended strongly on the microstructure of the weld fusion zone. Although it was found that the cracking susceptibility was influenced by the presence of Fe-Al intermetallic phases (namely Fe3 Al and FeAl), the cracking behavior of FeAlCr weld overlay claddings also depended on the size and distribution of carbide and oxide particles present within the weld structure. These particles acted as hydrogen trapping sites, which are areas where free hydrogen segregates and can no longer contribute to the hydrogen embrittlement of the metal. It was determined that in practical applications of these FeAlCr weld overlay coatings, carbon should be present within these welds to reduce the amount of hydrogen available for hydrogen cracking. Based on the weldability results of the FeAlCr weld claddings, coating compositions that were able to be deposited crack-free were used for long-term corrosion testing in a simulated low NOx environment. These alloys were compared to a Ni-based superalloy (622), which is commonly utilized as boiler tube coatings in power plant furnaces for corrosion protection. It was found that the FeAlCr alloys demonstrated superior corrosion resistance when compared to the Ni-based superalloy. Due to the excellent long-term corrosion behavior of FeAlCr weld overlays that were immune to hydrogen cracking, it was concluded that select FeAlCr weld overlay compositions would make excellent corrosion resistant

  19. Resistance Spot Weldability of Dissimilar Materials: BH180-AISI304L Steels and BH180-IFT123 Steels

    Institute of Scientific and Technical Information of China (English)

    Fatih Hayat

    2011-01-01

    In this study, resistance spot weldability of 180 grade bake hardening steel (BH180), 7123 grade interstitial free steel (IF7123) and 304 grade austenitic stainless steel (AISI304L) with each other was investigated. In the joining process, electrode pressure and weld current were kept constant and six different weld time were chosen. Microstructure, microhardness, tensile-shear properties and fracture types of resistance spot welded joints were examined. In order to characterize the metallurgical structure of the welded joint, the microstructural profile was developed, and the relationship between mechanical properties and microstructure was determined. The change of weld time, nugget diameter, the HAZ (heat affected zone) width and the electrode immersion depth were also investigated. Welded joints were examined by SEM (scanning electron microscopy) images of fracture surface. As a result of the experiment, it was determined that with increasing weld time, tensile shear load bearing capacity (TLBC) increased with weld time up to 25 cycle and two types of tearing occurred. It was also determined that while the failure occurred from IF side at the BHIS0+IF7123 joint, it occurred from the BH180 side at the BHIS0+AISI304L joint.

  20. Study on Welding Mechanism Based on Modification of Polypropylene for Improving the Laser Transmission Weldability to PA66.

    Science.gov (United States)

    Liu, Huixia; Jiang, Hairong; Guo, Dehui; Chen, Guochun; Yan, Zhang; Li, Pin; Zhu, Hejun; Chen, Jun; Wang, Xiao

    2015-08-04

    Polypropylene and PA66 are widely used in our daily life, but they cannot be welded by laser transmission welding (LTW) because of polar differences and poor compatibility. In this paper, grafting modification technology is used to improve the welding performance between polypropylene and PA66. Firstly, the strong reactive and polar maleic-anhydride (MAH) is grafted to polypropylene and infrared spectrometer is used to prove that MAH has been grafted to polypropylene. At the same time, the mechanical and thermal properties of the graft modified polypropylene (TGMPP) are tested. The results prove that the grafting modification has little influence on them. Also, the optical properties of TGMPP are measured. Then, the high welding strength between TGMPP and PA66 is found and the mechanism of the weldability is researched, which shows that there are two reasons for the high welding strength. By observing the micro morphology of the welding zone, one reason found is that the modification of polypropylene can improve the compatibility between polypropylene and PA66 and make them easy to diffuse mutually, which causes many locking structures formed in the welding region. The other reason is that there are chemical reactions between TGMPP and PA66 proved by the X-ray photoelectron spectrometer.

  1. Corrosion resistance of weldable super 13Cr stainless steel in H{sub 2}S containing CO{sub 2} environments

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, M.; Amaya, H.; Kondo, K. [Sumitomo Metal Industries, Ltd., Amagasaki (Japan). Iron and Steel Research Labs.; Ogawa, K. [Sumitomo Metal Industries, Ltd., Osaka (Japan); Mori, T. [Wakayama Steel Works (Japan)

    1996-08-01

    The weldable super 13Cr stainless steel was investigated because of the application for flow line in CO{sub 2} environments with a little amount of H{sub 2}S. TIG welding in the condition of no post weld heat treatment (PWHT) was used as the welding technique. The lowering of C content less than 0.01 mass% in the weldable steel decreased a maximum hardness in the heat-affected zone(HAZ) and mitigated the sulfide stress cracking (SSC) susceptibility. The increasing of Mo content from 2.0 mass% of the super 13Cr stainless steel OCTG (0.02C-12Cr-5.5Ni-2Mo) to 2.5 mass% improved SSC resistance in the HAZ. Based on these results, the weldable super 13Cr stainless steel, which consisted of 0.007C-12Cr-6Ni-2.5Mo-Ti, has been developed. The welded-joint with the yield strength of 550 MPa (80 ksi) and enough corrosion resistance was completed by using the welding material of super duplex stainless steel which had 25Cr-9Ni-3Mo-2W-0.3N. The corrosion resistance to SSC at room temperatures and localized-corrosion at elevated temperatures of the welded-joint was the same as the super 13Cr stainless steel OCTG. The improvement effect of the corrosion resistance by means of Mo addition was discussed based on the stability of Cr oxide passive film, the analysis results of the surface film formed in the CO{sub 2} environment containing H{sub 2}S, and calculated-solubility of oxides, FeCO{sub 3} and sulfides in that environment. It was clarified that Mo assisted the formation of the Cr oxide passive film in the inner layer of the surface film and the formation of Mo sulfide in the outer layer.

  2. An Analysis of the Weldability of Ductile Cast Iron Using Inconel 625 for the Root Weld and Electrodes Coated in 97.6% Nickel for the Filler Welds

    Directory of Open Access Journals (Sweden)

    Francisco-Javier Cárcel-Carrasco

    2016-11-01

    Full Text Available This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The welds were performed on ductile cast iron specimen test plates sized 300 mm × 90 mm × 10 mm with edges tapered at angles of 60°. The plates were subjected to two heat treatments. This article analyzes the influence on weldability of the various types of electrodes and the effect of preheat treatments. Finally, a microstructure analysis is made of the material next to the weld in the metal-weld interface and in the weld itself. The microstructure produced is correlated with the strength of the welds. We treat an alloy with 97.6% Ni, which prevents the formation of carbides. With a heat treatment at 900 °C and 97.6% Ni, there is a dissolution of all carbides, forming nodules in ferritic matrix graphite.

  3. Review of the concept and of the equations of the weldability window for explosive welding. Application to the explosive welding of stainless steel to carbon steel in cylindrical configuration

    Science.gov (United States)

    Ribeiro, Jose; Mendes, Ricardo; Loureiro, Altino

    2013-06-01

    Explosive cladding/welding is usually considered a solid state process in which the detonation of a certain amount of an explosive composition is used to accelerate one of the materials to be weld against the other. By this way a high velocity oblique collision is promoted and that will be responsible for the materials bonding. The conditions that should be met to achieve good welds define what is called as a weldability window or criteria. A weldability criteria based on the collision point velocity (Vc) and on the collision angle (β) is the most used today. In the β-Vc space the weldability window is defined by four lines or limits. Despite of its widely used in explosive welding works, neither the concepts behind those limits neither the equations used to define them in the β-Vc space are particularly clear. Contradictory concepts, and equations with undefined variables or parameters, are commonly found in the literature. This paper aims to clarify those concepts and equations through an integrated description of the weldability limits and a presentation of the reviewed associated equations with the variables and parameters, including their units, clearly defined. The reviewed concepts and equations are then used for the description of the explosive welds of stainless steel to carbon steel in cylindrical configuration.

  4. Weldability of the Anti-sulfide Corrosion X60 Gas Pipeline Steel%抗硫化物腐蚀的X60输气管线钢的焊接性

    Institute of Scientific and Technical Information of China (English)

    米秋占

    2001-01-01

    Introduced the weldability of the X60 pipeline steel transmittingof gas with high H2S and analyzed the result of the test.%介绍了输送含H2S较高的天然气X60管线钢焊接性。并对试验结果进行了分析。

  5. Weldability of polycrystalline aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Fasching, A.A.; Edwards, G.R.; Burt, R.P. [Colorado School of Mines, Golden, CO (United States); David, S.A. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    Slow strain rate tensile tests were conducted in varying water vapor atmospheres on weldments refined by magnetic arc oscillation with average fusion zone grain sizes ranging between 115 and 530{mu}m. Fracture strength and percent strain to fracture were measured for each fusion zone microstructure. The fracture strength data followed Hall-Petch behavior, and water vapor significantly reduced fracture strength. The finer grain size fusion zones were found to be less susceptible to hydrogen cracking and more tolerant of high hydrogen concentrations than coarse fusion zone grain structures. Microstructural refinement via arc oscillation was also found to be suitable only for well-controlled fabrication environments.

  6. Weldability of thin sheet metals by small-scale resistance spot welding using high-frequency inverter and capacitor-discharge power supplies

    Science.gov (United States)

    Zhou, Y.; Dong, S. J.; Ely, K. J.

    2001-08-01

    An investigation has been conducted of the weldability of 0.2-mm-thick sheet aluminum, brass, and copper in small-scale resistance spot welding using a high-frequency inverter and a capacitor-discharge power supply. The results have been compared to those of previous investigations using a line-frequency alternating current power supply. The effects of electrode materials and process parameters on joint strength, nugget diameter, weld-metal expulsion and electrode-sheet sticking were studied. This work has also provided practical guidelines for selection of power supplies, process parameters (welding current/pulse energy, welding time/pulse width, electrode forces, etc.) and electrode materials for small-scale resistance spot welding of thin sheet aluminum, brass and copper.

  7. Weldability and Welding Technique of 2101 Duplex Stainless Steel%2101双相不锈钢的焊接性能和焊接技术

    Institute of Scientific and Technical Information of China (English)

    刘长文; 邓钢; 曾广庭

    2012-01-01

    对2101双相不锈钢的焊接性能进行了分析,并提出了几个关键的焊接技术,最后以12.7mm厚2101双相不锈钢板为例,进行了该材料的焊接工艺评定。结果表明:在合理的焊接方法和焊接参数下,2101双相不锈钢具有良好的焊接性能。%Weldability of 2101 duplex stainless steel was analyzed, several key welding techniques were put forward, and finally welding procedure qualification was done taken 12. 7 mm 2101 duplex stainless steel plate as an example. The results show that 2101 duplex stainless steel has good welding performance under the condition of reasonable welding method and welding parameters.

  8. An investigation on weldability of AISI 304 and AISI 1040 steels on friction welding; Untersuchung der Schweisseignung von AISI 304 und AISI 1040 mittels Reibschweissen

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Sare; Ay, Irfan [Balikesir Univ., Cagis Campus (Turkey). Mechanical Eng. Dept.; Dinc, Dincer [General Directorate of Highways, Canakkale (Turkey); Yaman, Ramazan [Balikesir Univ., Cagis Campus (Turkey). Industrial Eng. Dept.

    2010-04-15

    In welding technology, joining processes of different materials, which have dissimilar crystal structures are difficult. Welding of different materials becomes very important to reduce costs. Furthermore, the friction welding method is processed in lower temperature than the melting temperature. Especially, this is a big advantage to overcome difficulties that occur in the heat affected zone during usage of conventional methods. In this study, the weldability of AISI 304 stainless steel and AISI 1040 carbon steel by friction welding is studied. During the welding process, temperature variations in the welding zones were measured with an infrared temperature measurement device. After welding of the samples, tensile and hardness experiments were carried out. For metallographic investigations, optical microscope and scanning electron microscope (SEM) pictures were taken. Energy dispersive spectroscopy (EDS) analysis was carried out for composition investigations on welding and heat affected zones. As a result, these two steels could be joined by friction welding for industrial usage.

  9. 马氏体不锈钢HFW管线管的开发%Development of Weldable Martensitic Stainless Steel Line Pipe by HFW Process

    Institute of Scientific and Technical Information of China (English)

    肖国章; 高霞; 马星; 赵波锋

    2014-01-01

    A new type of martensitic stainless steel line pipe having excellent weldability and high corrosion resistance in wet CO2 environments manufactured by the high-frequency electric-resistance welding (HFW) process was developed. Through optimized design alloy composition, metallographic structure observation, mechanical property test, the steel pipe external dimension and anticorrosion performance test, the external dimension, mechanical properties of base metal and weld, and metallographic structure of the developed steel pipe can meet the design requirements. The test results showed that the new martensitic stainless steel can produce thin-walled and high precision line pipe, the gas shield welding techniques can be used in HFW; preheat before welding and heat treatment after welding don’t need for HFW steel pipe, the pipe body and weld can satisfy the condition of wet CO2 in oil and gas well.%研究开发了一种具有良好可焊性和抗湿CO2腐蚀的马氏体不锈钢合金及HFW焊管。通过合金成分优化设计、金相组织观察、力学性能试验、钢管外观尺寸及防腐性能试验,所开发的钢管外观尺寸、母材和焊缝的力学性能及金相组织等满足设计目标要求,与传统马氏体不锈钢管相比,具有更精确的外观尺寸。试验结果表明,新型可焊接马氏体不锈钢可以生产薄壁高精度管线管,可以用气体保护技术进行HFW焊接; HFW钢管不需焊前预热和焊后热处理,管体及焊缝所有性能满足油气井湿CO2腐蚀的服役环境。

  10. Weldability of Advanced High Strength Steels using Ytterbium:Yttrium Aluminium Garnet high power laser for Tailor-Welded Blank applications

    Science.gov (United States)

    Sharma, Rajashekhar Shivaram

    transverse direction were evaluated. Metallographic examinations determined that most of the fusion zone is martensitic with small regions of bainite and ferrite. High microhardness values of the order of 550--600 Hv were noted in most joints, which are attributed to high alloy content of the fusion zone as well as high rates of cooling typical of laser welds. During tensile, fatigue and formability tests, no fractures in the fusion or heat affected zones were observed. Geometric variability evaluations indicated that coatings such as aluminum (in the case of USIBOR) and galvanized zinc (TRIP780) can affect the variability of the weld zone and the surface roughness on the top of the weld. Excessive variability in the form of weld concavity in the weld zones can lead to fractures in the weld region, even though higher hardness can, to some extent, compensate for these surface irregularities. The 2-factor design of experiments further confirmed that coatings adversely affect the surface roughness on the top of the welds. Although thickness differentials alone do not make a significant impact on surface roughness, together with coatings, they can have an adverse effect on roughness. Tensile tests in the direction of rolling as well as in the transverse direction indicate that TRIP780 seems weaker in the direction of rolling when compared to transverse direction while mild steel is stronger in the direction of rolling. Weldability analyses revealed that the typical melting efficiency is on the order of 50--70% for full penetration welding. Formability tests showed that TR/MS joints fractured in a direction parallel to the weld line when tested with the loads perpendicular to the weld line. Tests have also confirmed that weld speed and power have no impact on the outcome of formability results. Overall, this work conclusively proves that high power Yb:YAG lasers can effectively join high strength materials such as DP980, TRIP780, USIBOR, as well as mild steel, for use in tailor

  11. Investigation of the effect of temper condition on the friction-stir weldability of AA7075 Al-alloy plates: Raziskovanje učinka popuščanja plošče iz aluminijeve zlitine AA7075 na varivost s trenjem:

    OpenAIRE

    Çam, Gürel; Erim, Seçil; Ipekoglu, Güven; Kiral, Binnur Gören

    2012-01-01

    Al-alloys are widely used in the transportation industries due to their low density and excellent formability properties. These alloys, which are problematic in fusion-welding processes, can be successfully joined by friction-stir welding. Particularly high-strength AA7075 alloy is considered to be non-weldable by fusion welding. Friction-stir welding, being a solid-state joining technique, can also be successfully used in joining other difficult-to-weld alloys. In this study, 3.17-mm-thick, ...

  12. Laser weldability of Pt and Ti alloys

    Energy Technology Data Exchange (ETDEWEB)

    Noolu, N.J. [Center for Advanced Materials Joining, University of Waterloo, Waterloo (Canada)]. E-mail: nnoolu@mecheng1.uwaterloo.ca; Kerr, H.W. [Center for Advanced Materials Joining, University of Waterloo, Waterloo (Canada); Zhou, Y. [Center for Advanced Materials Joining, University of Waterloo, Waterloo (Canada); Xie, J. [Cardiac Rhythm Management Division, Street Jude Medical Inc., Sylmar, CA (United States)

    2005-04-25

    Crack susceptibility of laser spot welds between Pt and Ti alloys was studied by characterizing the surface and the cross-sections of the welds produced at different pulse energies. Increase in laser pulse energy increased the dilution by the Ti alloy, giving rise to the evolution of microstructures with varying Ti contents across the entire fusion zone. Hardness results showed that regions with 66-75% Ti, i.e. consisting of primary Ti{sub 3}Pt and/or Ti{sub 3}Pt + TiPt eutectic, have a hardness higher than 700 Vickers hardness numbers (VHN), while regions with 42-66% Ti, i.e. consisting of primary TiPt, possessed hardness between 400 and 700 VHN. The extent of cracking increased with the increase in pulse energy and the cracked regions consisted of Ti contents between 50 and 75%. Brittle cracking in microstructures consisting of Ti{sub 3}Pt and TiPt phases suggested that one or both of the constituent phases are susceptible to cracking. However, crack arrest in microstructures predominantly consisting of TiPt showed that Ti{sub 3}Pt is the most susceptible phase to cracking in Pt-Ti alloy welds.

  13. Hydrogen degradation of high strength weldable steels

    OpenAIRE

    J. Ćwiek

    2007-01-01

    Purpose: Purpose of this paper is presentation of hydrogen degradation issue of high strength steels andespecially their welded joints. Establishing of applicable mechanisms of hydrogen-enhanced cracking was theaim of performed research.Design/methodology/approach: High strength quenched and tempered steels grade S690Q were used. Weldedjoints were prepared with typical technology used in shipyards. Susceptibility to hydrogen degradation in seawater under cathodic polarization was evaluated wi...

  14. Process for electroplating of highly pure and weldable gold coating using K{Au(Ⅰ)[CH2(CN)2]}2(C6H5O7)·H2O as main salt%以丙尔金为主盐的高纯度可焊性镀金工艺

    Institute of Scientific and Technical Information of China (English)

    张荣光; 周大龙

    2012-01-01

    以清洁环保的丙尔金[即一水合柠檬酸一钾二(丙二腈合金(Ⅰ))]代替有毒氰化亚金钾为主盐,用市售的可焊性镀金工艺配方及规范,生产高纯度(99.99%)的金镀层.所得镀金层呈浅柠檬黄色、无色斑,比亚硫酸盐纯金层更均匀、致密,金线键合强度经高低温循环试验后稳定,与载体焊接牢固、无空穴,满足美国军标MIL-STD-883H-2010中方法2011.8——键合强度测试规范的性能要求.镀金液性能与亚硫酸盐纯金镀液相近.镀金液使用3年多后,不论是在加热状态或是长期放置都很稳定.%A highly pure (99.99%) gold coating was prepared by using environmentally friendly bis(malononitrile) gold(I) potassium citrate monohydrate as main salt in replace of toxic gold potassium cyanide based on the bath composition and operation parameters of a commercial weldable gold plating process. The obtained gold coating is pale lemon yellow and stain-free, and more uniform and compact than the pure gold coating prepared from a sulfite bath. The bonding strength of gold wire is stable after cyclic treatment between high and low temperatures, and is welded firmly without any seam to the carrier, meeting the requirement of U.S. Military standard M1L-STD-883H-2010 Method 2011.8-Testing Specification of Bonding Strength. The properties of gold plating bath are similar to those of sulfite gold plating bath. The bath is stable whether it is heated or placed for long after using for more than 3 years.

  15. Weldability of AISI 304 to copper by friction welding

    Energy Technology Data Exchange (ETDEWEB)

    Kirik, Ihsan [Batman Univ. (Turkey); Balalan, Zulkuf [Firat Univ., Elazig (Turkey)

    2013-06-01

    Friction welding is a solid-state welding method, which can join different materials smoothly and is excessively used in manufacturing industry. Friction welding method is commonly used in welding applications of especially cylindrical components, pipes and materials with different properties, for which other welding methods remain incapable. AISI 304 stainless steel and a copper alloy of 99.6 % purity were used in this study. This couple was welded in the friction welding machine. After the welding process, samples were analyzed macroscopically and microscopically, and their microhardness was measured. Tensile test was used to determine the bond strength of materials that were joined using the friction welding method. At the end of the study, it was observed that AISI 304 stainless steel and copper could be welded smoothly using the friction welding method and the bond strength is close to the tensile strength of copper. (orig.)

  16. Underwater Explosive Welding, Discussion Based on Weldable Window

    Science.gov (United States)

    Mori, A.; Tamaru, K.; Hokamoto, K.; Fujita, M.

    2006-07-01

    A new method of underwater explosive welding is introduced and its possibilities are suggested. In the underwater explosive welding, a high explosive with detonation velocity of 7km/s is placed at an initial inclined angle to decrease the horizontal collision point velocity, which is one of the important parameters to achieve welding. This method is effective to accelerate a thin metal plate rapidly. However, this arrangement makes a difference in the welding conditions with horizontal position when a constant thickness explosive is used, as the propagation distance of the underwater shock wave increases at the ends. Hence, a method of linearly increasing the thickness of explosive in proportion to the propagation distance is proposed. This investigation intends to clarify the welding conditions in using a constant thickness explosive and linearly increasing thickness explosive based on numerical analysis. Further, a method of designing the assembly is confirmed through numerical analysis and its validity with the experimental results is demonstrated based on the welding window.

  17. The properties and weldability of materials for fusion reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Chin, B.A.; Kee, C.K.; Wilcox, R.C. [Auburn Univ., AL (United States). Dept. of Mechanical Engineering; Zinkle, S.J. [Oak Ridge National Lab., TN (United States)

    1991-11-15

    Low-activation austenitic stainless steels have been suggested for applications within fusion reactors. The use of these nickel-free steels will help to reduce the radioactive waste management problem after service. one requirement for such steels is the ability to obtain sound welds for fabrication purposes. Thus, two austenitic Fe-Cr-Mn alloys were studied to characterize the welded microstructure and mechanical properties. The two steels investigated were a Russian steel (Fe-11.6Cr19.3Mn-0.181C) and an US steel (Fe-12.lCr-19.4Mn-0.24C). Welding was performed using a gas tungsten arc welding (GTAW) process. Microscopic examinations of the structure of both steels were conducted. The as-received Russian steel was found to be in the annealed state. Only the fusion zone and the base metal were observed in the welded Russian steel. No visible heat affected zone was observed. Examination revealed that the as-received US steel was in the cold rolled condition. After welding, a fusion zone and a heat affected zone along with the base metal region were found.

  18. A Weldability Study of Structural Materials for Manufacturing Bearing Separators

    Directory of Open Access Journals (Sweden)

    V. S. Drizhov

    2016-01-01

    Full Text Available The aim is to analyze the possibility for using the 08YUT steel separator tape to manufacture separators, which are to be further applied to the bearing assembly via projection welding.Reliability of rolling bearings is determined by many factors such as surface quality of balls and rings and assembly precision, including the seal strength of hemiseparators.The technology based on the double-pulsed condenser projection welding belongs to one of the most efficient technologies to provide the assembly of bearing, for it allows welding of separator simultaneously in all currents. The paper shows that the required condition to assure high reliability of the bearing is induastial development and implementation of an effective and positive quality control system, which will reduce the probability of damages occurring both when welding and in the course of operation.The work used the static tensile test methods, as well as metallographic analysis.The experimental study used the 08YUT steel hemiseparators. A tape thickness of the hemiseparators was of 1.5mm. The number of simultaneously welded points were 8. The experimental studies of the metal damage of welding joints of the the 08YUT steel separator have shown that with a wide range of the changing welding current and compressed electrode force the quality assurance of welding points at the parent metal level could not be retrieved.The metallographic analysis of the metal damage nature of a welded joint revealed that between the atoms on the surfaces of hemiseparators there are no strong bonds – a bond was formed in the contact zone. This phenomenon leads to reduced tensile seal strength.The study has shown that aluminum and titanium added to the low-carbon steel in order to have a more fine-grained metal structure has a negative effect on the quality of welded joint via projection welding.

  19. Weldability and Strength Recovery of NUCu-140 Advanced Naval Steel

    Science.gov (United States)

    Bono, Jason T.

    NUCu-140 is a ferritic copper-precipitation strengthened steel that is a candidate material for use in many naval and structural applications. Previous work has shown that the heat-affected zone (HAZ) and fusion zone (FZ) of NUCu-140 exhibit softening that is due to dissolution of the copper-rich precipitates. This study aims to recover the FZ and HAZ strength by re-precipitation of the copper-rich precipitates through either multiple weld passes or an isothermal post-weld heat treatment (PWHT). The potential use of multiple thermal cycles was investigated with HAZ simulations using a Gleeble thermomechanical simulator. The HAZ simulations represented two weld thermal cycles with different combinations of peak temperatures during the initial and secondary weld passes. To investigate the potential for a PWHT for strength recovery, gas tungsten arc weld (GTAW) samples were isothermally heated for various times and temperatures. Microhardness measurements revealed no strength recovery in the multipass HAZ samples. The time dependent precipitate characteristics were modeled under the HAZ thermal cycle conditions, and the results showed that the lack of strength recovery could be attributed to insufficient time for re-precipitation during the secondary weld pass. Conversely, full strength recovery in the HAZ was observed in the isothermally heat treated samples. Atom-probe tomography (APT) analysis correlated this strength recovery to re-precipitation of the copper-rich precipitates during the isothermal PWHT. The experimental naval steel known as NUCu-140 and an established naval steel HSLA-100 were subjected to stress-relief cracking (SRC) and hot-ductility testing to assess their relative cracking susceptibilities during the welding process and post weld heat treatment. NUCu-140 exhibited a longer time-to-failure (TTF) and a lower temperature of minimum TTF during SRC testing when compared to HSLA-100, indicating better resistance to SRC for the NUCu-140 steel. The lowest TTF for NUCu-140 occurred in the temperature range of 500-550°C (932-1022°F), and was contributed to the achievement of maximum hardness as a result of ageing of Cu-rich precipitates at this temperature. HSLA-100 exhibited a minimum TTF at 650°C (1202°F), and this was attributed to the formation of austenite at this temperature. HSLA-100 and NUCu-140 exhibited a relatively narrow liquation cracking temperature ranges (LCTR) of 32°C (90°F) and 36°C (97°), respectively. The low susceptibility of both alloys was attributed to the formation of delta-ferrite within the same temperature range as incipient melting. Ineffective wetting and liquid film discontinuity in both alloys was established through metallographic and fractographic analysis.

  20. Weldability investigation steel P 91 by weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2015-07-01

    Full Text Available This paper elaborates results of hardness and impact energy of thermal cycle simulated specimens of high-alloy steel P 91 and their dependence on cooling time from 800 to 500 °C. Results were obtained by measuring hardness HV 1 and by experimental testing of Charpy notched specimens. Metallographic analysis of samples was performed on scanning electronic microscope.

  1. The Weldability of Heat-Resisting Alloys (N-102)

    Science.gov (United States)

    1945-12-05

    turbosupsrehargera, jat engines, and gas turbina wheals. Welds in fiva wrought alloya and two cast materials nera aubjacted to tha bead-on-plate test...superchar.jers, jet engines, and gas turbine wheels. ThiSc investigations are basing continued oy tht .tustluss Iron and steel Corporation, a3 a...characteristics of heat resisting alloys enployod in turbo-superchargers,jet anginas, and gas turbine wheels. The primary objectives wore tho development of

  2. Investigation of Steels for Improved Weldability in Ship Construction.

    Science.gov (United States)

    1984-05-01

    transformation products from Widmanstatten ferrite, pearlite, and bainite to a more equiaxed ferrite and pearlite microstructure. Additions of residuals (Cu + Ni...ferrite and the type of AL.. microconstituents present (pearlite, bainite , or martensite). Microstructures of the HAZ’s of all the steels after simulated...martensite and bainite . The final group of steels all contained vanadium. Th’. plain vanadium steel V1 had a slightly higher CVN transition temperature

  3. Resistance Spot Weldability of Galvanize Coated and Uncoated TRIP Steels

    Directory of Open Access Journals (Sweden)

    Hayriye Ertek Emre

    2016-11-01

    Full Text Available In this study, the resistance spot weldabilty of zinc galvanize-coated and uncoated TRIP800 steels was investigated in detail. Depending on the welding parameters such as welding current and welding time, the effects of zinc coating on the weld nugget geometry, the tensile shear strength, the failure modes, the hardness, and the microstructure of the resistance spot-welded sample were studied, and the results are compared with that of uncoated weldment. The coating on the surface of the TRIP steel causes a decrease in the weld nugget size and tensile shear strength of the weldment, and it changes to failure mode of the test sample from pullout to interfacial or partial interfacial fracture. As compared with the uncoated sample, the galvanized TRIP800 steel weldment has required a larger critical nugget size for achieving the desired pullout fracture mode and acceptable tensile shear strength.

  4. Studies on the weldability, microstructure and mechanical properties of activated flux TIG weldments of Inconel 718

    Energy Technology Data Exchange (ETDEWEB)

    Ramkumar, K. Devendranath, E-mail: ramdevendranath@gmail.com; Kumar, B. Monoj; Krishnan, M. Gokul; Dev, Sidarth; Bhalodi, Aman Jayesh; Arivazhagan, N.; Narayanan, S.

    2015-07-15

    This research article addresses the joining of 5 mm thick plates of Inconel 718 by activated flux tungsten inert gas (A-TIG) welding process using SiO{sub 2} and TiO{sub 2} fluxes. Microstructure studies inferred the presence of Nb rich eutectics and/or laves phase in the fusion zone of the A-TIG weldments. Tensile studies corroborated that the ultimate tensile strength of TiO{sub 2} flux assisted weldments (885 MPa) was better compared to SiO{sub 2} flux assisted weldments (815 MPa) and the failure was observed in the parent metal for both the cases. Impact test results portrayed that both the weldments were inferior in toughness as compared to the parent metal, which was due to the presence of oxide inclusions. Also, the study investigated the structure–property relationships of the A-TIG weldments of Inconel 718.

  5. Weldability prediction of high strength steel S960QL after weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2014-10-01

    Full Text Available This paper presents weld thermal cycle simulation of high strength steel S960QL, and describes influence of cooling time t8/5 on hardness and impact toughness of weld thermal cycle simulated specimens. Furthermore, it presents analysis of characteristic fractions done by electron scanning microscope which can contribute to determination of welding parameters for S960QL steel.

  6. Variable amplitude corrosion fatigue and fracture mechanics of weldable high strength jack-up steels

    OpenAIRE

    Etube, L. S.

    1998-01-01

    The tubular welded joints used in the construction of Offshore structures can experience millions of variable amplitude wave induced stress cycles during their operational life. Fatigue has been identified as the main cause of degradation of structural integrity in these structures. As a result, fatigue is an important consideration in their design. Jack-up legs are made from a range of high strength steels with yield strengths up to 70OMPa. These steels are thought to exhib...

  7. Literature Review: Weldability of Iridium DOP-26 Alloy for General Purpose Heat Source

    Energy Technology Data Exchange (ETDEWEB)

    Burgardt, Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pierce, Stanley W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-10-19

    The basic purpose of this paper is to provide a literature review relative to fabrication of the General Purpose Heat Source (GPHS) that is used to provide electrical power for deep space missions of NASA. The particular fabrication operation to be addressed here is arc welding of the GPHS encapsulation. A considerable effort was made to optimize the fabrication of the fuel pellets and of other elements of the encapsulation; that work will not be directly addressed in this paper. This report consists of three basic sections: 1) a brief description of the GPHS will be provided as background information for the reader; 2) mechanical properties and the optimization thereof as relevant to welding will be discussed; 3) a review of the arc welding process development and optimization will be presented. Since the welding equipment must be upgraded for future production, some discussion of the historical establishment of relevant welding variables and possible changes thereto will also be discussed.

  8. Effect of weld schedule variation on the weldability and durability of AHSS spot weld joints

    Science.gov (United States)

    Weishaupt, Eric Raymond

    Tensile strength testing and high cycle fatigue testing of advanced high strength steel spot welded shear lap joints were performed for the various weld conditions. The materials used in this study were DP 980, DP 780 and TRIP 780. The microstructure and microhardness of the shear lap joints were examined in an effort to identify the effect of microstructural changes on the strength and fatigue durability of the spot weld specimens. The occurrence of interfacial failure was recorded for the differing weld processes. Several weld schedules were examined and used to produce shear lap spot weld joints, specifically varying the squeeze force and the average current. The weld force used to produce a spot weld does not have a significant effect on the fracture mode of the specimen given the average current is constant. The average current used to produce a spot weld has a significant effect on the fracture mode of the spot weld for several squeeze forces. Interfacial failure of spot welded TRIP 780 can be mitigated using a certain range of currents when welding. This appears to come as a tradeoff for sacrificing the strength of the joint. Higher values of weld strength were obtainable; however, welds that failed with higher strengths also experienced interfacial failure. A fracture mechanics approach to estimating the high cycle fatigue life of the shear lap specimen is also proposed and represents a conservative estimate of the shear lap specimen durability.

  9. Weldability of 2219-T851 and 2519-T87 Aluminum Armor Alloys for Use in Army Vehicle Systems

    Science.gov (United States)

    1987-06-01

    CONTRACT OR GRANT NUMBER(s) Thomas D. Wolfe and Steven A. Gedeon S. PERFORMING ORGANIZATION N•AME AND ADDRESS 10. PROGRAM FLEMENT PROJECT. TASK AREA ...the desired configur- ation and then impacting the welded area (direct hit on the weld for flat plates, and 2 inches from the weld for a corner joint...whereas in the 7XXX series the copper remains in a relatively uniform distribucion . Also, no discrete particles of Al-Zn-Mg are found in 7XXX series

  10. Microstructure characterization and weldability evaluation of the weld heat affected zone (HAZ) in 310HCbN tubing

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-08-01

    Metallographic evaluation on the Gleeble simulated HAZ samples of 310HCbN tubing material was performed in order to reveal potential degradation in mechanical properties and corrosion resistance. The carbide evolutionary process in the HAZ samples was studied. It is indicated that 310HCbN material showed a weld HAZ sensitization tendency that is associated with the formation of Cr{sub 23}C{sub 6}.

  11. The Effect of Tool Press Force to Weldability of AA5754 and AA6061 Alloys with Friction Stir Welding Method

    Directory of Open Access Journals (Sweden)

    Tevfik Küçükömeroğlu

    2013-07-01

    Full Text Available In this study AA5754 and A6061 alloys have been butt welded to each other by using friction stir welding (FSW. At constant tool geometry and tool angle experiments were carried out, joints were performed using different welding speed, rotation speed and especially tool press force. The mechanical properties of the welded samples were determined by using tensile test, bending test and micro hardness. Generated microstructure and hardness profile was obtained in the welding zone. In this friction stir welding study the parameters which affect the joint structure are the tool press force, welding speed and tool rotation speed which were determined. At the end of study it is determined that AA5754 and AA6061 alloys can be successfully welded by using Friction Stir Welding method under different tool press forces at least 6kN.

  12. Numerical evaluation of the weldability of the low alloy ferritic steels T/P23 and T/P24

    Directory of Open Access Journals (Sweden)

    Carlos Roberto Xavier

    2011-03-01

    Full Text Available A model based on transport equations was numerically implemented by the finite volume method (FVM in a computational code in order to simulate the influence of the heat input, base metal thickness and preheating temperature on the thermal evolution and the cooling rate during the welding of the low alloy ferritic steels T/P23 and T/P24. As a consequence, it was possible to evaluate qualitatively the microstructure at the heat affected zone (HAZ of these steels when a single weld bead was deposited on their surface and calculate the maximum hardness reached at this region. Goldakfs double-ellipsoid heat source model for power density distribution was utilized in order to obtain a good estimate of the cooling rate and dimensions of the fusion zone (FZ. The results are discussed in light of previous work and good agreement between experimental and simulated results was verified.

  13. Study on the welding continuous cooling transformation and weldability of SA508Gr4 steel for nuclear pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Qingwei; Ma, Yonglin; Xing, Shuqing; Chen, Zhongyi [Inner Mongolia Univ. of Science and Technology, Baotou (China). School of Material and Metallurgy; Kang, Xiaolan [Baotou Vocational and Technical College (China)

    2017-02-15

    SA508Gr4 is a newly developed high-strength steel for nuclear reactor pressure vessels. Its welding characteristics remain largely unexplored. In this work, the simulated heat affected zone continuous cooling transformation (SH-CCT) diagram of SA508Gr4 steel was constructed and the high-temperature cooling phase compositions and the properties of the heat affected zone (HAZ) were characterized using dilatometry and microscopic tests. The results show that the phase transformation in the HAZ was divided into bainite and martensite transformation stages. When 4.6 ≤ t{sub 8/5} (the HAZ cooling time from 800 C to 500 C) ≤ 15 s, lath-shaped martensite was fully developed, resulting in extensive hardening and cold cracking in the HAZ, while the cooling time required to form the bainite completely exceeds 1 200 s. Thus, to improve weld quality, preheating to 196 C or higher is recommended.

  14. BT20钛合金激光焊技术研究%Research on Laser Fabrication Weldability of BT20 Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    Shuili Gong; Li Chen; Wei Yao

    2004-01-01

    By using CO2 laser beam and YAG laser beam, the butt welding of BT20 titanium alloy sheet with 2.5 mm thickness is carried out. It is found that the geometry of welded joint is different because of different laser beam models. The stable welding process and welding quality are guaranteed by using suitable welding parameters. On the condition of butt welding without welding wire, the welded defect such as undercut on the weld face is generated because of the heat physics properties of BT20 titanium alloy and the high energy density laser beam, which affects the mechanical properties of welded joint seriously, especially the fatigue strength and the fracture toughness. Using the active fluxes in the welding procedure, or making use of laser welding technique with filler wire, revolving scanning beam could be a good method to solve undercut and improve the mechanical properties of laser welded joint.%针对2.5 mm厚BT20钛合金进行了CO2激光焊和YAG激光焊研究,结果表明:由于激光特性不同,形成的焊缝几何特征不同,当焊接工艺适当,可保证焊接过程的稳定性和焊接接头的质量.在激光自熔焊时主要的焊缝缺陷是咬边,这是由于钛合金物理性能和激光高能束流焊特性所致.这种咬边缺陷不利于焊接接头性能,尤其是接头的疲劳性能和断裂韧性.采用活性剂和填丝焊,以及激光旋扫焊可以改善焊缝咬边缺陷,提高钛合金激光焊接头的力学性能.

  15. 保护气体种类对镀锌板激光焊接性的影响%The effect of shielding gas type on laser weldability of galvanized steel

    Institute of Scientific and Technical Information of China (English)

    李明星; 胡治华; 陈铠

    2006-01-01

    本文通过采用He、Ar、N2、以及Ar和N2的混合气体作为保护气体,研究了不同保护气对CO2激光镀锌板焊接性的影响.研究发现激光深熔焊接时的临界屏蔽功率密度在很大程度上受保护气体类型的影响.焊缝的熔深、强度和成形性主要取决于保护气体的类型.

  16. Effects of High Al and Hf Content on Weldability of Ni3Al Based Alloy by Laser Welding%高Al、Hf含量对Ni3Al基合金激光焊接性能的影响

    Institute of Scientific and Technical Information of China (English)

    高海芸; 何润; 张冬云; 鹿堃

    2015-01-01

    为了研究高Al、Hf含量对Ni3Al基合金焊接性能的影响,采用激光焊接3种成分合金,分析焊缝凝固机理,并对比所得裂纹敏感性,同时从预热温度、激光光源性质等方面研究激光焊接工艺.Al元素成分增加,使合金降低了焊缝裂纹中偏析较严重的Mo元素含量,并使凝固过程的脆性温度范围减小,离共晶区较远,致使凝固组织(γ+γ')共晶相减少.Hf元素含量增加使枝晶间得到良好的填充,使其相变成细密羽毛状(γ+γ ')共晶体,明显降低合金的裂纹敏感性.通过调节母材预热温度,激光波长,在冷却速度较快时能够在一定程度上降低裂纹的敏感性,但仍未完全消除裂纹.而采用波长较短、光斑面积较大的半导体激光焊接得到无裂纹焊缝.

  17. Weldability of Low Carbon and High Niobium X80 Pipeline Steel and Its Engineering Practice%低碳高铌X80管线钢焊接性及工程实践

    Institute of Scientific and Technical Information of China (English)

    尚成嘉; 王晓香; 刘清友; 付俊岩

    2012-01-01

    Low carbon high Nb and high Mn microalloying design has been applied to X80 pipeline steel , the longitudinal and submerged arc weling performance of X80 line pipe are of prime importance to application of the said alloy system. The results of thermal simulation study showed that the optimum heat input energy for alloy system X80 steel should be lower than 30 kj/cm. The grain size of CGHAZ of high Nb pipeline steel is smaller than that of common Nb steel; the coarse precipitates do not appear in ICCGHAZ, and the size of Nb(CN) is not more than 30nm. A large number of production data indicated that the mechanical properties of HAZ in high Nb X80 pipeline steel, especially the toughness, can reach high level, which can fully meet the requirements of the Second West-east Gas Pipeline Project The application of this alloy system provided the Second West-east Gas Pipeline Project with powerful safeguard.%低C高Nb高Mn的合金设计已广泛应用于X80管线钢,X80管线钢钢管的直缝焊接以及螺旋缝焊接性能对该合金体系的应用极其重要.热模拟研究结果表明,该合金体系X80管线钢的最佳热输入量应低于30 kJ/cm.相比于普通Nb含量管线钢,高Nb含量设计管线钢的粗晶区(CGHAZ)晶粒尺寸更细;临界粗晶区(ICCGHAZ)并没有粗大的析出物,Nb(CN)的尺寸≤30 nm.直缝焊及螺旋焊X80钢管的大量工业生产数据表明,高Nb X80管线钢热影响区的力学性能,特别是韧性能达到较高的水平,完全满足西气东输二线的技术指标,该合金体系的应用为西气东输二线的成功建成提供了有力保障.

  18. Investigation of joining techniques for advanced austenitic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P.; Kikuchi, Y.; Shi, C.; Gill, T.P.S.

    1991-05-01

    Modified Alloys 316 and 800H, designed for high temperature service, have been developed at Oak Ridge National Laboratory. Assessment of the weldability of the advanced austenitic alloys has been conducted at the University of Tennessee. Four aspects of weldability of the advanced austenitic alloys were included in the investigation.

  19. Determinação dos campos de soldabilidade para o aço Dual-Phase 600 em equipamentos de soldagem a ponto AC e MFDC Determination of weldability fields for Dual-Phase 600 steel in AC and MFDC RSW

    Directory of Open Access Journals (Sweden)

    Marco Antonio Wolff

    2010-09-01

    Full Text Available A soldagem utilizada na indústria automobilística encontra num momento de escolha entre dois tipos principais de equipamentos para a soldagem a ponto por resistência: fonte que usam ou corrente alternada (AC ou corrente contínua média-freqüência (MFDC. A primeira tecnologia (fontes AC é a mais tradicional e tem sido utilizada com sucesso na soldagem de chapas de aços de baixo-carbono, com relativo baixo custo. Por outro lado, a tecnologia mais recente (fonte MFDC tem sido descrita pelos seus fabricantes como uma evolução na soldagem a ponto por resistência ao se aumentar a produtividade, reduzir o consumo de energia elétrica, propiciar melhor controle dos parâmetros e menor estresse termo-mecânico. Além destas vantagens, observando-se o aspecto construtivo das fontes MFDC, estas demandam menores transformadores, uma vez que a eficiência de um transformador é proporcional à freqüência de entrada da rede elétrica, i.e., 60 Hz no caso do Brasil para as fontes AC, ao passo que esta freqüência chega a 1000 Hz no caso das fontes MFDC, reduzindo, assim, seu tamanho. Embora importantes, tais vantagens têm sido alardeadas sem a devida comprovação científica, em especial durante a aplicação dos aços de mais alta resistência. Dentre estes aços, os aços dual-phase têm iniciado sua expansão. Desta forma, este trabalho procurar comparar equipamentos AC e MFDC do ponto de vista de envelope operacional (campo de soldabilidade para a soldagem a ponto por resistência de aços dual-phase com limite de resistência de 600 MPa. Para tanto, a metodologia de comparação foi definida com base no tamanho equivalente do ponto de solda. Como resultado final, encontrou-se que para menores correntes, o campo de soldabilidade obtido com o equipamento MFDC foi maior, diminuindo à medida que se aumenta a corrente de soldagem.The automotive industry faces nowadays a challenge of choosing between two types of current for resistance spot welding equipments: AC (alternating current and MFDC (medium-frequency direct current. The first technology (AC equipment is the traditional one and has been successfully applied to accomplish weldments in low-carbon steel sheets, with relatively low cost. On the other hand, the new technology (MFDC equipment has been propagated by the manufactures as an evolution of the resistance spot welding, where higher productivity, lower energy consumption, better parameters controlling and lower thermal-mechanical stress. Besides these claimed qualities, from the construction point of view, the MFDC equipment demands smaller transformers, since its efficiency is proportional to the input frequency, i.e., the AC equipment uses the 60-Hz (in the Brazilian case from the power lines, whereas the MFDC ones goes for 1000 Hz, increasing its efficiency and reducing its size. Despite these commercial claims of the MFDC-equipment manufacturers, few scientific results have been published with a thorough methodology of comparison, especially for the recently introduced dual-phase steels. Therefore, this work is aimed to provide the comparison between MFDC and AC resistance spot welding equipment by using an appropriated methodology based on the equivalent size of the obtained spot. It is expected the results lead to further discussion between the use of these two equipments.

  20. 镁合金焊丝成分对镁钢异种金属CMT焊接性的影响%Effect of composition of magnesium alloy welding wire on weldability of heterogeneous metals of magnesium with steel by using CMT welding

    Institute of Scientific and Technical Information of China (English)

    陈剑虹; 余建永; 曹睿; 王培中

    2012-01-01

    Cold metal transfer (CMT) welding was used to lap the dissimilar metallic sheets of magnesium alloy AZ31B and galvanized steel plate HDG60, and three magnesium wire AZ92, AZ61,AND MnE21 were employed in the welding experiment. The result showed that a better weld could be formed with these wires in the case of appropriate welding parameters. However, the welding window of the AZ92 and AZ61 was wider, and that with MnE21 was narrower and noticeable cracks took place at the weld. It was shown by the analysis of joint interface microstructure that the joint would be divided into weld zone, brazing zone, and fusion zone. It resulted from the analysis of X-ray diffraction that, when the magnesium welding wire of AZ92 and AZ61 was employed, there could mainly be magnesium solid solution and such compounds as MgFeAlO4, Mg2Zn11 , and Al12Mg17 in the welding joint interface. When MnE21 was used as welding wire, there would basically be Mg solid solution and compounds Mg32Al49 and Al12Mg12 there. The results showed that the tensile sheerload of the joint reached 87. 5% of the magnesium base material with same dimensions when AZ61 wire was used. When other two Mg wires were used, the tensile sheer load would be less. In short, AZ61 wire would be more suitable for joining dissimilar metals between the magresium and steel.%采用CMT冷金属过渡焊对异种金属AZ31B镁合金板和HDG60镀锌钢板进行焊接,试验中采用AZ92、AZ61、MnE21镁合金焊丝.结果表明:在合适的工艺参数下,3种焊丝都能形成较好的焊缝,但AZ92、AZ61焊丝的焊接窗口比较宽,而MnE21焊丝的焊接窗口极窄,并且焊缝处有明显的裂纹.接头的界面组织分析表明,焊接接头被分成焊缝区、中间结合区、熔合区.通过X射线衍射分析得出,当采用AZ92、AZ61镁合金焊丝时,焊接结合面主要有Mg的固溶体,还有MgFeAlO4、Mg2Zn11、Al12 Mg17等化合物;采用MnE21镁合金焊丝时,焊接结合面主要有Mg固溶体,还有Mg32 Al49、Al12Mg17化合物.在拉伸试验中.采用相同规格的拉伸试样,使用AZ61焊丝的接头拉剪力可达镁母材的87.5%.而采用其他2种焊丝时拉剪力较小.由此可见,AZ61焊丝更适合焊接镁钢异种金属.

  1. The influence of electric ARC activation on the speed of heating and the structure of metal in welds

    National Research Council Canada - National Science Library

    Savytsky Oleksandr M; Savytsky Mychailo M; Bajić Darko R; Shkrabalyuk Yuriy M; Vuherer Tomaž

    2016-01-01

    .... It is confirmed that ATIG and AMIG methods, depending on metal thickness, single pass weldability and chemical composition of activating flux, enable the reduction of welding energy by 2-6 times when...

  2. 49 CFR 178.39 - Specification 3BN seamless nickel cylinders.

    Science.gov (United States)

    2010-10-01

    .... A reasonably smooth and uniform surface finish is required. Cylinders closed in by spinning process... nonpressure parts, and only to the tops and bottoms of cylinders. Neckrings and footrings must be of weldable...

  3. Assessment of Al-Li Alloys for Cryotanks

    Science.gov (United States)

    Babel, Henry W.; Bozich, William; Farahmand, Bob; DeJesus, Ron; Sankaran, K. K.; Schwab, Dave; Tarkanian, Mike; Funk, Joan G. (Technical Monitor)

    2002-01-01

    This viewgraph presentation provides information on steps undertaken to determine the suitability of Aluminum and Lithium alloys in cryogenic tank construction. Major characteristics are offered for several different candidate alloys including reliability, weldability, flammability, and required thicknesses.

  4. ARc Welding (Industrial Processing Series).

    Science.gov (United States)

    ARC WELDING , *BIBLIOGRAPHIES), (*ARC WELDS, BIBLIOGRAPHIES), ALUMINUM ALLOYS, TITANIUM ALLOYS, CHROMIUM ALLOYS, METAL PLATES, SPOT WELDING , STEEL...INERT GAS WELDING , MARAGING STEELS, MICROSTRUCTURE, HEAT RESISTANT ALLOYS, HEAT RESISTANT METALS, WELDABILITY, MECHANICAL PROPERTIES, MOLYBDENUM ALLOYS, NICKEL ALLOYS, RESISTANCE WELDING

  5. Resistance Spot Welding with Middelfrequency-Inverter Weling Gun

    DEFF Research Database (Denmark)

    Rasmussen, Mogens H.

    The paper presents the results of investigations concerning the process stability and weldability lobes for uncoated sheets of 1.0 mm thickness when performing resistance spot welding with a middlefrequency-inverter welding gun......The paper presents the results of investigations concerning the process stability and weldability lobes for uncoated sheets of 1.0 mm thickness when performing resistance spot welding with a middlefrequency-inverter welding gun...

  6. Resistance Spot Welding with Middelfrequency-Inverter Weling Gun

    DEFF Research Database (Denmark)

    Rasmussen, Mogens H.

    The paper presents the results of investigations concerning the process stability and weldability lobes for uncoated sheets of 1.0 mm thickness when performing resistance spot welding with a middlefrequency-inverter welding gun......The paper presents the results of investigations concerning the process stability and weldability lobes for uncoated sheets of 1.0 mm thickness when performing resistance spot welding with a middlefrequency-inverter welding gun...

  7. Investigations of Spot Weld Material Characterization for Hat Beam Component Impact Analysis

    OpenAIRE

    Sachin Patil; Hamid Lankarani

    2016-01-01

    With a greater emphasis placed on weight reduction the ground vehicle industry has increased the use of higher strength, thinner gage steels, particularly cold rolled high strength steels (HSS). Choice of a particular HSS will depend upon such factors as cost, formability, fatigue resistance and weldability, in particular spot weldability. Vehicle collision characteristics significantly influenced by spot welded joints in vehicle steel body components.In engineering practice, spot welds are n...

  8. Structure formation and properties of a copper-aluminum joint produced by ultrasound-assisted explosive welding

    Science.gov (United States)

    Kuz'min, E. V.; Peev, A. P.; Kuz'min, S. V.; Lysak, V. I.

    2017-08-01

    The effect of ultrasound-assisted explosive welding on the structure formation and the properties of copper-aluminum joints is studied. Ultrasound-assisted explosive welding improves the quality of formed copper-aluminum joints, i.e., enhances their strength and significantly reduces the amount of fused metal over the entire weldability range. It is shown that ultrasound-assisted explosive welding can noticeably extend the weldability range of the copper-aluminum pair to obtain equal-in-strength joints with minimum structural heterogeneity in the wide welding range.

  9. Effects of surface treatments of galvanized steels on projection welding procedure

    Institute of Scientific and Technical Information of China (English)

    王敏; 王宸煜

    2003-01-01

    A group of projection welding experiments and joints tension-shear tests are carried out for cold-rolled steel sheets, galvanized steel sheets (GSS) without treatment, GSS with phosphating and GSS with surface greasing, respectively. The experimental results are regressively analyzed on the computers, then the projection welded joint tension-shear strength curve and the perfect welding currents range of each material are obtained. The results show that surface treatments of galvanized steels have effects on their spot weldabilities. Among the four kinds of materials, GSS with surface greasing have the worst spot weldability, for they need higher welding current and have a narrow welding current range.

  10. Design of the Advanced High Kinetic Energy Launch System

    Science.gov (United States)

    1982-08-01

    of 41,800 psi. ASTM 574 A516 steel was used for the dome because it is easy to shape and is readily weldable . ASTM A572, Grade 60 is classified as...stirrups were used at 12 or 14 inches, as required. The reinforcement used was ASTM A615 , Grade 60 except for the stirrups for which Grade 40 was used...a high strength, low alloy structural steel and was used for its availability, high strength, and weldability for the rest of the structure. The

  11. Hybrid manufacturing processes for fusion welding and friction stir welding of aerospace grade aluminum alloys

    Science.gov (United States)

    Gegesky, Megan Alexandra

    Friction stir welding and processing can provide for joints in aerospace grade aluminum alloys that have preferable material properties as compared to fusion welding techniques. Aerospace grade aluminum alloys such as AA2024-T3 and AA7075-T6 are considered non-weldable by traditional fusion welding techniques. Improved mechanical properties over previously used techniques are usually preferable for aerospace applications. Therefore, by combining traditional fusion welding and friction stir processing techniques, it could be plausible to create more difficult geometries in manufactured parts instead of using traditional techniques. While this combination of fusion welding and friction stir processing is not a new technology, its introduction to aerospace grade aluminum alloys as well as non-weldable alloys, is new. This is brought about by a lowered required clamping force required by adding a fusion weld before a friction stir processing technique. The changes in properties associated with joining techniques include: microstructural changes, changes in hardness, tensile strength, and corrosion resistance. This thesis illustrates these changes for the non-weldable AA2024-T351 and AA7075-T651 as well as the weldable alloy AA5052-H32. The microhardness, tensile strength and corrosion resistance of the four processing states: base material, fusion welded material, friction stir welded material, and friction stir processed fusion welded material is studied. The plausibility of this hybrid process for the three different materials is characterized, as well as plausible applications for this joining technique.

  12. Vacuum Gas Tungsten Arc Welding

    Science.gov (United States)

    Weeks, J. L.; Todd, D. T.; Wooten, J. R.

    1997-01-01

    A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

  13. Characterizing of steel used in the construction of civil works in Almeria; Caracterizacion mecanica de aceros empleados en el sector de la construccion de Almeria

    Energy Technology Data Exchange (ETDEWEB)

    Senobua, A. J.; Garzon, E.; Ayuso, J.; Perez, F.; Caballero, A.

    2003-07-01

    Various tests have been conducted on the steel bars used in the construction of civil works in Almeria (Spain) during the period 18 January 2000-7May 2001, with the aim of mechanically characterizing the different types of steel (weldable; B400S, B500S and ductile weldable: B400SD) to determine whether there is a technical reason for the increase in the use of ductile weldable steel. For this, we have used a hydraulic machine to break by traction all the test samples that arrived to the laboratory, following the specifications of the UNE 7474-1:1992 and the UNE 7474-2:1992. The results indicate that only in 86% of the cases does the steel B400SD satisfy the limits specified by the UNE 36065:1999-EX, as opposed to 95 and 94% of the B400S and B500S steels. In addition the ductile weldable steel registered mean values lower than those of B400S. This findings disagrees with expectations set by the specifications. (Author) 6 refs.

  14. Hot-cracking studies of Inconel 718 weld- heat-affected zones

    Science.gov (United States)

    Thompson, E. G.

    1969-01-01

    Hot ductility tests, gas-tungsten-arc fillerless fusion tests, and circle patch-weld-restraint tests were conducted on Inconel 718 to better understand and correlate the weldability /resistance to hot cracking/ of the alloy. A correlation of the test results with composition, heat-treat condition, grain size, and microstructure was made.

  15. Second Annual Progress Report on Radiation Tolerance of Controlled Fusion Welds in High Temperature Oxidation Resistant FeCrAl Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Briggs, Samuel A. [Univ. of Wisconsin, Madison, WI (United States)

    2016-12-30

    The present report summarizes and discusses the current results and on-going activity towards developing a modern, nuclear grade FeCrAl alloy designed to have enhanced radiation tolerance and weldability under the Department of Energy (DOE) Nuclear Energy Enabling Technologies (NEET) program.

  16. Effect of heat treatment on the properties of laser-beam welded rheo-cast F357 aluminum

    CSIR Research Space (South Africa)

    Theron, M

    2012-02-01

    Full Text Available Semi-solid metal rheo-cast F357 aluminum plates were joined by autogenous Nd:YAG laser welding and were welded in either the as-cast (F) condition, T4 temper or T6 temper condition. The weldability of this age-hardenable Al–7%Si–0.6%Mg casting alloy...

  17. Systematic Review of Ultrasonic Impact Treatment Parameters on Residual Stresses of Welded Non-Sensitized Versus Sensitized Aluminum-Magnesium

    Science.gov (United States)

    2015-03-01

    plastic deformation UIT ultrasonic impact treatment UTS ultimate tensile strength wt% weight percent XRD x-ray diffractometry xv THIS PAGE...steel Excellent corrosion resistance Weldability Ease of forming, bending and machining High thermal and electrical conductivity Recyclable Non...stresses are internal to the material and are generated when a material undergoes plastic deformation (fabrication or joining of materials), large

  18. Critical Materials Needs

    Science.gov (United States)

    1975-08-11

    composition which yield high levels of toughness, improved workability, and weldability. The comparison of the hitjh-purity, essentially inclusion ^ ree ESR...Soath Windsor, Connecticut William H. Podolny, Fuel Cell Program Manager Wire Journal Branford, Connecticut Laurence W. Collins, Jr

  19. Marangoni driven free surface flows in liquid weld pools

    NARCIS (Netherlands)

    Saldi, Z.S.

    2012-01-01

    Extending the weldability of novel materials, and improving the weld quality by tailoring weld microstructures are key factors to obtain the welding techniques demanded in the modern manufacturing industries. This can be done, for example, by feeding chemical elements from a consumable wire into the

  20. 49 CFR 178.56 - Specification 4AA480 welded steel cylinders.

    Science.gov (United States)

    2010-10-01

    ... by spinning process not permitted. (b) Steel. The limiting chemical composition of steel authorized... the tops and bottoms of cylinders is authorized. Provided that such attachments are made of weldable... material which have been previously welded to the top or bottom of cylinders and properly heat treated...

  1. Expanding the Availability of Lightweight Aluminum Alloy Armor Plate Procured From Detailed Military Specifications

    Science.gov (United States)

    2012-07-01

    published an investigation into ‘Bullet Resisting Alloys’ where, utilizing a Japanese Army service rifle and a ballistic pendulum , he examined numerous...materials that offer possible benefits such as lower cost, higher strength, better ballistic and corrosion resistance, improved weldability, etc. 15...selection of armor materials that offer possible benefits such as lower cost, higher strength, better ballistic and corrosion resistance, improved

  2. Marangoni driven free surface flows in liquid weld pools

    NARCIS (Netherlands)

    Saldi, Z.S.

    2012-01-01

    Extending the weldability of novel materials, and improving the weld quality by tailoring weld microstructures are key factors to obtain the welding techniques demanded in the modern manufacturing industries. This can be done, for example, by feeding chemical elements from a consumable wire into the

  3. A Combined Electrochemical and Microstructural Analysis of Model AlMgSi(Cu) Alloys

    NARCIS (Netherlands)

    Zhan, H.; Mol, J.M.C.; Terryn, H.A.; De Wit, J.H.W.

    2007-01-01

    Application prospects in automotive and aerospace industry have led to extensive studies on AA6xxx alloys in recent years because of their attractive combinations of properties. The benefits include formability, weldability, high strength to weight ratio and low cost. The main alloying elements in t

  4. Weld nugget formation in resistance spot welding of new lightweight sandwich material

    DEFF Research Database (Denmark)

    Sagüés Tanco, J.; Nielsen, Chris Valentin; Chergui, Azeddine

    2015-01-01

    Weldability of a new lightweight sandwich material, LITECOR®, by resistance spot welding is analyzed by experiments and numerical simulations. The spot welding process is accommodated by a first pulse squeezing out the non-conductive polymer core of the sandwich material locally to allow metal–me...

  5. Weld solidification cracking in 304 to 204L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Hochanadel, Patrick W [Los Alamos National Laboratory; Lienert, Thomas J [Los Alamos National Laboratory; Martinez, Jesse N [Los Alamos National Laboratory; Johnson, Matthew Q [Los Alamos National Laboratory

    2010-09-15

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found.This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GTAW showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  6. Weld solidification cracking in 304 to 304L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Hochanadel, Patrick W [Los Alamos National Laboratory; Lienert, Thomas J [Los Alamos National Laboratory; Martinez, Jesse N [Los Alamos National Laboratory; Martinez, Raymond J [Los Alamos National Laboratory; Johnson, Matthew Q [Los Alamos National Laboratory

    2010-01-01

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found. This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GT A W showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  7. Interface relief upon explosion welding: Splashes and waves

    Science.gov (United States)

    Greenberg, B. A.; Ivanov, M. A.; Inozemtsev, A. V.; Kuz'min, S. V.; Lysak, V. I.; Vlasova, A. M.; Pushkin, M. S.

    2015-04-01

    For copper-tantalum, aluminum-tantalum, and magnesium-titanium joints the character of the interface relief has been investigated in different regimes of explosion welding at, below, and above the lower limit of weldability. It has been found for the first time that protrusions on the plane interface have the shape of splashes. This shape is unusual with allowance for the fact that protrusions arise from the solid phase that experienced no melting. Upon transitioning to the region below the lower limit, the number of splashes decreases and they prove to be insufficient to provide weldability. Upon transitioning to a region somewhat above the lower limit, the interface becomes quasi-wavy and inhomogeneous and, in some places, in addition to the wavy surface, splashes are also observed. Splashes and waves have been observed simultaneously for the first time. Models that describe possible variants of their interrelation have been proposed.

  8. Effects of B4C Addition on the Laser Beam Welding Characteristics of Al/SiC MMCs Produced By P/M

    Directory of Open Access Journals (Sweden)

    Serdar KARAOĞLU

    2011-01-01

    Full Text Available Fusion weldability characteristics of metal matrix composites (MMC produced by powder metallurgy (P/M are usually insufficient due to unwanted micro-structural changes that occur during welding. This study aims to investigate the effects of B4C addition as reinforcement on the weld quality of Al/SiC MMCs. After the production of Al/SiC MMCs by P/M with or without the addition of B4C, laser beam welding (LBW characteristics of the materials were investigated by focusing on the integrity of the welds. Optical microscopy (OM, scanning electron microscopy (SEM, and energy dispersive X-ray analysis (EDX were utilized for the characterization of the welds. Results show that Al/SiC MMCs produced by P/M can not be easily welded by LBW, but weldability characteristics of the material can be improved by the addition of B4C.

  9. Diode laser welding of ABS: Experiments and process modeling

    CERN Document Server

    Ilie, Mariana; Mattei, Simone; Cicala, Eugen; Stoica, Virgil; 10.1016/j.optlastec.2008.10.005

    2010-01-01

    The laser beam weldability of acrylonitrile/butadiene/styrene (ABS) plates is determined by combining both experimental and theoretical aspects. In modeling the process, an optical model is used to determine how the laser beam is attenuated by the first material and to obtain the laser beam profile at the interface. Using this information as the input data to a thermal model, the evolution of the temperature field within the two components can be estimated. The thermal model is based on the first principles of heat transfer and utilizes the temperature variation laws of material properties. Corroborating the numerical results with the experimental results, some important insights concerning the fundamental phenomena that govern the process could be extracted. This approach proved to be an efficient tool in determining the weldability of polimeric materials and assures a significant reduction of time and costs with the experimental exploration.

  10. A powder metallurgy austenitic stainless steel for application at very low temperatures

    CERN Document Server

    Sgobba, Stefano; Liimatainen, J; Kumpula, M

    2000-01-01

    The Large Hadron Collider to be built at CERN will require 1232 superconducting dipole magnets operating at 1.9 K. By virtue of their mechanical properties, weldability and improved austenite stability, nitrogen enriched austenitic stainless steels have been chosen as the material for several of the structural components of these magnets. Powder Metallurgy (PM) could represent an attractive production technique for components of complex shape for which dimension tolerances, dimensional stability, weldability are key issues during fabrication, and mechanical properties, ductility and leak tightness have to be guaranteed during operation. PM Hot Isostatic Pressed test plates and prototype components of 316LN-type grade have been produced by Santasalo Powdermet Oy. They have been fully characterized and mechanically tested down to 4.2 K at CERN. The fine grained structure, the absence of residual stresses, the full isotropy of mechanical properties associated to the low level of Prior Particle Boundaries oxides ...

  11. Susceptibility testing for welding of AlMg alloys intended for extrusion

    Directory of Open Access Journals (Sweden)

    J. Borowski

    2016-07-01

    Full Text Available The objective of research was to determine the weldability, using Tungsten Inert Gas (TIG of extruded sections made of hard-deformable 5xxx series aluminum alloys with differing magnesium content, i.e. AlMg3, AlMg4,5, AlMg5, AlMg7. Welded joints were obtained as a result of a welding process consisting of several steps. Only welds characterized by very good appearance and quality were selected for tests. As a result of conducted research, TIG welding parameters were determined for sections with a thickness of 8 mm. It was observed that alloys of differing Mg content are characterized by high weldability and do not exhibit a significant reduction of the yield point. Moreover, joints exhibit uniform hardness distribution in the welded joint and heat-affected zone. Tensile strength is reduced.

  12. Development of fabrication procedure for Korean HCCR TBM

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jae Sung, E-mail: jsyoon2@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Suk Kwon; Lee, Eo Hwak; Shin, Ku In; Jin, Hyung Gon; Choi, Bo Guen; Lee, Dong Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Korea has developed and plans to test a helium cooled ceramic reflector (HCCR) test blanket module (TBM) in the ITER. The HCCR TBM is composed of four sub-modules and a back manipulator (BM). Each sub-module is composed of a first wall (FW), breeding box, and side walls (SW). The fabrication procedure was developed to confirm the fabrication method for the HCCR TBM. The test specimens of the ARAA were prepared to test the weldability for tungsten inert gas (TIG) welding and electron beam (EB) welding. To establish and optimize the welding procedure in an EB weld from ARRA material, the variation in the bead width and penetration depth according to the welding current and welding speed were investigated. To verify the weldability and fabrication procedure for a complex structure such as the breeding zone, a small box with a cooling channel is being fabricated using the ARAA steel under development.

  13. Laser beam welding of titanium nitride coated titanium using pulse-shaping

    Directory of Open Access Journals (Sweden)

    Milton Sergio Fernandes de Lima

    2005-09-01

    Full Text Available A new welding method which allows the assembly of two titanium nitride coated titanium parts is proposed. The welding procedure utilizes the possibility for pulse-shaping in order to change the energy distribution profile during the laser pulse. The pulse-shaping is composed of three elements: a a short high power pulse for partial ablation at the surface; b a long pulse for thermal penetration; and c a quenching slope for enhanced weldability. The combination of these three elements produces crack-free welds. The weld microstructure is changed in comparison to normal welding, i.e. with a rectangular pulse, as the nitrogen and the microhardness are more homogenously distributed in the weld under pulse-shaping conditions. This laser pulse dissolves the TiN layer and allows nitrogen to diffuse into the melt pool, also contributing to an enhanced weldability by providing suitable thermal conditions.

  14. Pathological changes waterproof membranes and their identification

    Directory of Open Access Journals (Sweden)

    Novotný Marek

    2017-01-01

    Full Text Available With the development of waterproofing systems based on synthetic membranes, especially mPVC, there is an increase in pathological changes of these membranes. Competing manufacturers and pressure on price of the final product have resulted in usage of unstable or low quality raw materials. After production, these materials keep their specific characteristics, however, their aging is accelerated, i.e. they lose their essential qualitative characteristics very quickly. Very important is the detection of these processes which is possible using chemical analysis (gas chromatography, IR analysis and others as well as using visual inspection of surface by microscope, including 3D modeling. Very important are weldability tests which identify glass transition temperature of the material. The results can then be used as a basis for correct identification of problems with weldability, nonweldability of synthetic membranes, respectively, as well as for identification of normal or abnormal aging of these materials.

  15. Progress in thermomechanical control of steel plates and their commercialization

    OpenAIRE

    Kiyoshi Nishioka and Kazutoshi Ichikawa

    2012-01-01

    The water-cooled thermomechanical control process (TMCP) is a technology for improving the strength and toughness of water-cooled steel plates, while allowing control of the microstructure, phase transformation and rolling. This review describes metallurgical aspects of the microalloying of steel, such as niobium addition, and discusses advantages of TMCP, for example, in terms of weldability, which is reduced upon alloying. Other covered topics include the development of equipment, distortio...

  16. Welding Process for Low Alloy Cast Steels by CO2 Welding%低合金铸钢件的CO2气体保护焊工艺

    Institute of Scientific and Technical Information of China (English)

    赵丽玲

    2012-01-01

    The weldability of low alloy cast steels was analyzed. The problems produced during welding were understood. And then the CO2 gas shielded welding process was introduced.%通过对低合金铸钢的焊接性分析,了解其在焊接过程中易产生的问题,进而介绍了其CO2焊工艺.

  17. Alloys For Corrosive, Hydrogen-Rich Environments

    Science.gov (United States)

    Mcpherson, William B.; Bhat, Biliyar N.; Chen, Po-Shou; Kuruvilla, A. K.; Panda, Binayak

    1993-01-01

    "NASA-23" denotes class of alloys resisting both embrittlement by hydrogen and corrosion. Weldable and castable and formed by such standard processes as rolling, forging, and wire drawing. Heat-treated to obtain desired combinations of strength and ductility in ranges of 100 to 180 kpsi yield strength, 120 to 200 kpsi ultimate tensile strength, and 10 to 30 percent elongation at break. Used in place of most common aerospace structural alloy, Inconel(R) 718.

  18. Numerical modeling of linear friction welding:a literature review

    Institute of Scientific and Technical Information of China (English)

    李文亚; 郭嘉; 马铁军; A.Vairis

    2014-01-01

    Linear friction welding (LFW)is a solid state process for joining metals together.While this process was developed originally for titanium alloys (e.g.blisks),over the past decade a number ofmaterials were found to be weldable with LFW. In this review,the current status ofunderstanding and development ofLFW are presented.Particular emphasis has been given to the modeling ofthe LFW process.Finally,opportunities for further research and development ofLFW are identified.

  19. Microstructural Development during Welding of TRIP steels

    OpenAIRE

    Amirthalingam, M.

    2010-01-01

    The Advanced High Strength Steels (AHSS) are promising solutions for the production of lighter automobiles which reduce fuel consumption and increase passenger safety by improving crash-worthiness. Transformation Induced Plasticity Steel (TRIP) are part of the advanced high strength steels which offers a high strength and toughness combination with excellent uniform elongation. However, the higher alloying content of these steel limits their weldability and the thermal cycle of a welding proc...

  20. Evaluation of the Benefits of HSLA Steels

    Science.gov (United States)

    1989-03-01

    quenched and tempered steels , such as HY80 and HY1OO, require preheat and interpass temperature controls during welding of plates thicker than 1/2 inch...interpass tempera- tures and heat input limitations. Strict adherence to these requirements is mandatory to avoid cracking in hydrogen- sensitive steels ...requirement and excellent weldability of this steel will probably lower produc- tion costs and cracking -related repairs enough to overcome the slight

  1. Intermetallic particles-induced pitting corrosion in 6061-T651 aluminium alloy

    CSIR Research Space (South Africa)

    Mutombo, K

    2011-07-01

    Full Text Available -Induced Pitting Corrosion in 6061-T651 Aluminium Alloy Kalenda Mutombo Council for Scientific and Industrial Research (CSIR), South Africa kmutombo@csir.co.za Keywords: pitting corrosion, 6061-T651 aluminium alloy, intermetallic particles, 3.5% Na... extrudability, reasonable weldability and good corrosion resistance. This alloy finds widespread application in ship building and in the fabrication of tank containers for transporting various liquids. 6061-T651 aluminium alloy is, however, prone to pitting...

  2. Microstructure and Strength of Laser Welds of Sub-micron Particulate-reinforced Aluminum Martix Composite Al2O3p/6061Al

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The microstructure of laser welds of sub-micron particulate-reinforced aluminum matrix composite Al2O3p/6061Al and the weldability of the material were studied.Experimental results indicated that because of the huge specific surface area of the reinforcement,the interfacial reaction between the matrix and the reinforcement was restrained intensively at elevated temperature and pulsed laser beam.The main factor affecting the weldability of the composite was the reinforcement segregation in the weld resulting from the push of the liquid/solid interface during the solidification of the molten pool.The laser pulse frequency directly affected the reinforcement segregation and the reinforcement distribution in the weld,so that the weldability of the composite could be improved by increasing the laser pulse frequency.On the bases of this,a satisfactory welded joint of sub-micron particulate-reinforced aluminum matrix composite Al2Op/6061Al was obtained by using appropriate welding parameters.

  3. The Analysis of the General Performance and Mechanical Behavior of Unirradiated FeCrAl Alloys Before and After Welding

    Energy Technology Data Exchange (ETDEWEB)

    Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-06-03

    The present report summarizes and discusses the preliminary results for the in-depth characterization of the modern, nuclear-grade FeCrAl alloys currently under development. The alloys were designed for enhanced radiation tolerance and weldability, and the research is currently being pursued by the Department of Energy (DOE) Nuclear Energy Enabling Technologies (NEET) program. Last year, seven candidate FeCrAl alloys with well-controlled chemistry and microstructures were designed and produced; welding was performed under well-controlled conditions. The structure and general performance of unirradiated alloys were assessed using standardized and advanced microstructural characterization techniques and mechanical testing. The primary objective is to identify the best candidate alloy, or at a minimum to identify the contributing factors that increase the weldability and radiation tolerance of FeCrAl alloys, therefore enabling future generations of FeCrAl alloys to deliver better performance parameters. This report is structured so as to describe these critical assessments of the weldability; radiation tolerance will be reported on in later reports from this program.

  4. Ni-Flash-Coated Galvannealed Steel Sheet with Improved Properties

    Science.gov (United States)

    Pradhan, D.; Dutta, M.; Venugopalan, T.

    2016-11-01

    In the last several years, automobile industries have increasingly focused on galvannealed (GA) steel sheet due to their superior properties such as weldability, paintability and corrosion protection. To improve the properties further, different coatings on GA have been reported. In this context, an electroplating process (flash coating) of bright and adherent Ni plating was developed on GA steel sheet for covering the GA defects and enhancing the performances such as weldability, frictional behavior, corrosion resistance and phosphatability. For better illustration, a comparative study with bare GA steel sheet has also been carried out. The maximum electroplating current density of 700 A/m2 yielded higher cathode current efficiency of 95-98%. The performances showed that Ni-coated (coating time 5-7 s) GA steel sheet has better spot weldability, lower dynamic coefficient of friction (0.07 in lubrication) and three times more corrosion resistance compared to bare GA steel sheet. Plate-like crystal of phosphate coating with size of 10-25 µm was obtained on the Ni-coated GA. The main phase in the phosphate compound was identified as hopeite (63.4 wt.%) along with other phases such as spencerite (28.3 wt.%) and phosphophyllite (8.3 wt.%).

  5. Ni-Flash-Coated Galvannealed Steel Sheet with Improved Properties

    Science.gov (United States)

    Pradhan, D.; Dutta, M.; Venugopalan, T.

    2016-09-01

    In the last several years, automobile industries have increasingly focused on galvannealed (GA) steel sheet due to their superior properties such as weldability, paintability and corrosion protection. To improve the properties further, different coatings on GA have been reported. In this context, an electroplating process (flash coating) of bright and adherent Ni plating was developed on GA steel sheet for covering the GA defects and enhancing the performances such as weldability, frictional behavior, corrosion resistance and phosphatability. For better illustration, a comparative study with bare GA steel sheet has also been carried out. The maximum electroplating current density of 700 A/m2 yielded higher cathode current efficiency of 95-98%. The performances showed that Ni-coated (coating time 5-7 s) GA steel sheet has better spot weldability, lower dynamic coefficient of friction (0.07 in lubrication) and three times more corrosion resistance compared to bare GA steel sheet. Plate-like crystal of phosphate coating with size of 10-25 µm was obtained on the Ni-coated GA. The main phase in the phosphate compound was identified as hopeite (63.4 wt.%) along with other phases such as spencerite (28.3 wt.%) and phosphophyllite (8.3 wt.%).

  6. Strength Evaluation of Heat Affected Zone in Electron Beam Welded ARAA for HCCR TBM in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. S.; Kim, S. K.; Jin, H. G.; Lee, E. H.; Lee, D. W. [KAERI, Daejeon (Korea, Republic of); Cho, S. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The Korean helium cooled ceramic reflector (HCCR) test blanket module (TBM) has been developed for ITER, and Korean reduced activation ferritic martensitic (RAFM) steel, called advanced reduced activation alloy (ARAA), has also been developed for a structural material of the HCCR TBM. One case of limited optimized electron beam (EB) welding conditions was selected based on previous work, and the weldability of an EB weld was evaluated for TBM fabrication. The micro-hardness was measured from the base to the weld region, and the microstructures were also observed. A small punch (SP) test considering the HAZ was carried out at room and high (550 .deg. C) temperatures. The empirical mechanical properties of HAZ in the EB weld were evaluated, and the fracture behavior was investigated after the SP test. The SP results show that the estimated yield and tensile strength of the HAZ were higher than the base metal at both temperatures. Korean RAFM steel, ARAA, was developed as a TBM structural material. Using one of the program alloys in ARAA (F206), one case of a limited optimized EB welding condition was selected based on previous works, and the weldability of an EB weld using the SP test was evaluated for TBM fabrication at room and high (550 .deg. C) temperatures. From a micro-Vickers hardness evaluation, the HAZ gave the highest values compared with the other regions. The irregular grain boundaries in the HAZ were observed, but its width was narrower than the TIG weld from the previous results. The optimized welding methods such as the TIG, EB, and laser weld, and the welding procedure considering the PWHT are being established, and the weldability evaluation is also progressing according to the development of the ARAA for the fusion material application in Korea.

  7. Micro-alloying of steels. February 1977-April 1989 (Citations from the COMPENDEX data base). Report for February 1977-April 1989

    Energy Technology Data Exchange (ETDEWEB)

    1989-04-01

    This bibliography contains citations concerning production techniques, performance, and applications of microalloyed steels. Various microalloying materials are examined including niobium, vanadium, titanium, niobium/vanadium, aluminum, boron, molybdenum, and zirconium. Microalloying effects on the mechanical properties, corrosion resistance, metallurgical properties, and hot plasticity of steels are presented. Applications of microalloyed steels in the construction-steel industry, physical properties of microalloyed steels, low-temperature service behavior, weldability, formability, and resistance to corrosion are discussed. (Contains 81 citations fully indexed and including a title list.)

  8. Microalloying of steels. (Latest citations from the EI compendex*plus database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1994-12-01

    The bibliography contains citations concerning production techniques, performance, and applications of microalloyed steels. Various microalloying materials are examined including niobium, vanadium, titanium, niobium/vanadium, aluminum, boron, molybdenum, and zirconium. Microalloying effects on the mechanical properties, corrosion resistance, metallurgical properties, and hot plasticity of steels are presented. Applications of microalloyed steels in the construction steel industry, physical properties of microalloyed steels, low-temperature service behavior, weldability, formability, and resistance to corrosion are discussed. (Contains a minimum of 193 citations and includes a subject term index and title list.)

  9. Microalloying of steels. (Latest citations from the EI Compendex*plus database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The bibliography contains citations concerning production techniques, performance, and applications of microalloyed steels. Various microalloying materials are examined including niobium, vanadium, titanium, niobium/vanadium, aluminum, boron, molybdenum, and zirconium. Microalloying effects on the mechanical properties, corrosion resistance, metallurgical properties, and hot plasticity of steels are presented. Applications of microalloyed steels in the construction steel industry, physical properties of microalloyed steels, low-temperature service behavior, weldability, formability, and resistance to corrosion are discussed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  10. Microalloying of steels. (Latest citations from the Compendex database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    The bibliography contains citations concerning production techniques, performance, and applications of microalloyed steels. Various microalloying materials are examined including niobium, vanadium, titanium, niobium/vanadium, aluminum, boron, molybdenum, and zirconium. Microalloying effects on the mechanical properties, corrosion resistance, metallurgical properties, and hot plasticity of steels are presented. Applications of microalloyed steels in the construction steel industry, physical properties of microalloyed steels, low-temperature service behavior, weldability, formability, and resistance to corrosion are discussed. (Contains a minimum of 186 citations and includes a subject term index and title list.)

  11. Microalloying of steels. (Latest citations from the EI Compendex*plus database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-01

    The bibliography contains citations concerning production techniques, performance, and applications of microalloyed steels. Various microalloying materials are examined including niobium, vanadium, titanium, niobium/vanadium, aluminum, boron, molybdenum, and zirconium. Microalloying effects on the mechanical properties, corrosion resistance, metallurgical properties, and hot plasticity of steels are presented. Applications of microalloyed steels in the construction steel industry, physical properties of microalloyed steels, low-temperature service behavior, weldability, formability, and resistance to corrosion are discussed. (Contains a minimum of 190 citations and includes a subject term index and title list.)

  12. Laser Beam Welding with High-Frequency Beam Oscillation: Welding of Dissimilar Materials with Brilliant Fiber Lasers

    Science.gov (United States)

    Kraetzsch, Mathias; Standfuss, Jens; Klotzbach, Annett; Kaspar, Joerg; Brenner, Berndt; Beyer, Eckhard

    Brilliant laser beam sources in connection with a high frequent beam oscillation make it now possible to join metallic material combinations, which have been conventionally non-laser weldable up to now. It concerns especially such combinations like Al- Cu, where brittle intermetallic phases occur. Extreme small weld seam with high aspect ratio leads to very short meld pool life time. These allow an extensive reduction of the heat input. On the other side the melting behavior at metallic mixed joint, seam geometry, meld pool turbulence and solidification behavior can be influenced by a high frequent time-, position- and powercontrolled laser beam oscillation.

  13. Trends in the automotive paint industry for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Blandin, Nathalie; Brunat, William [PPG Industries France, 3 Z.A.E. Les Dix Muids, B.P. 89, F-59583 Marly (France); Neuhaus, Ralf [PPG Industries Lacke GmbH, Stackenbergstrasse 34, D-42329 Wuppertal (Germany); Sibille, Ettore [PPG Industries Italia, Via Serra11, I-15028 Quattordio (Italy)

    2004-07-01

    Since many years ED-paints are protecting car bodies against corrosion. Currently the automotive paint industry is faced with increasing demands of higher levels of corrosion protection and also requests to comply with new environmental regulations and economical pressures. Some key factors that contributed significantly towards the improvement of corrosion protection systems are: - New generations of lead free ED-paints; - Weldable organic thin film for corrosion protection, especially in box cavities and flange areas. The goal of this paper is to show how the various elements of the 'anti-corrosion package' interact. (authors)

  14. Problems in repair-welding of duplex-treated tool steels

    Directory of Open Access Journals (Sweden)

    T. Muhič

    2009-01-01

    Full Text Available The present paper addresses problems in laser welding of die-cast tools used for aluminum pressure die-castings and plastic moulds. To extend life cycle of tools various surface improvements are used. These surface improvements significantly reduce weldability of the material. This paper presents development of defects in repair welding of duplex-treated tool steel. The procedure is aimed at reduction of defects by the newly developed repair laser welding techniques. Effects of different repair welding process parameters and techniques are considered. A microstructural analysis is conducted to detect defect formation and reveal the best laser welding method for duplex-treated tools.

  15. Numerical and experimental analysis of resistance projection welding of square nuts to sheets

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Zhang, Wenqi; Martins, Paulo A.F.

    2014-01-01

    materials and applications require a new level of understanding of the process by combining finite element modelling and experimentation. This paper draws from the challenge of developing a three-dimensional computer program for electro-thermo-mechanical modeling of resistance welding and presents, as far......, reliability and validity of the theoretical and numerical developments. Numerical simulations support the evaluation of the experiments by providing detailed information on the process like the initial heating location and the following temperature development, and allowing to analyze the weldability...

  16. Characterization of Strain-Induced Precipitation in Inconel 718 Superalloy

    Science.gov (United States)

    Calvo, Jessica; Penalva, Mariluz; Cabrera, José María

    2016-08-01

    Inconel 718 presents excellent mechanical properties at high temperatures, as well as good corrosion resistance and weldability. These properties, oriented to satisfy the design requirements of gas turbine components, depend on microstructural features such as grain size and precipitation. In this work, precipitation-temperature-time diagrams have been derived based on a stress relaxation technique and the characterization of precipitates by scanning electron microscopy. By using this methodology, the effect of strain accumulation during processing on the precipitation kinetics can be determined. The results show that the characteristics of precipitation are significantly modified when plastic deformation is applied, and the kinetics are slightly affected by the amount of total plastic deformation.

  17. Welding Metallurgy and Processing Issues for Joining of Power Sources

    Energy Technology Data Exchange (ETDEWEB)

    Lienert, Thomas J. [Los Alamos National Laboratory; Reardon, Patrick T. [Los Alamos National Laboratory

    2012-08-14

    Weldability issues with the pertinent alloys have been reviewed and preliminary results of our work on Haynes 25 have been presented. Further results on the mechanical properties and metallography on the EB welds are imminent. Hot-ductility experiments will commence within a few weeks. Aging studies on the effects of heat treatment using the Gleeble are also planned. MST-6 has extensive background in the welding metallurgy of the pertinent alloys. We also have considerable experience with the various welding processes to be used.

  18. Comparison on welding mode characteristics of arc heat source for heat input control in hybrid welding of aluminum alloy

    Science.gov (United States)

    Song, Moo-Keun; Kim, Jong-Do; Oh, Jae-Hwan

    2015-03-01

    Presently in shipbuilding, transportation and aerospace industries, the potential to apply welding using laser and laser-arc hybrid heat sources is widely under research. This study has the purpose of comparing the weldability depending on the arc mode by varying the welding modes of arc heat sources in applying laser-arc hybrid welding to aluminum alloy and of implementing efficient hybrid welding while controlling heat input. In the experimental study, we found that hybrid welding using CMT mode produced deeper penetration and sounder bead surface than those characteristics produced during only laser welding, with less heat input compared to that required in pulsed arc mode.

  19. Cold Cracking Of Underwater Wet Welded S355G10+N High Strength Steel

    Directory of Open Access Journals (Sweden)

    Fydrych D.

    2015-09-01

    Full Text Available Water as the welding environment determines some essential problems influencing steel weldability. Underwater welding of high strength steel joints causes increase susceptibility to cold cracking, which is an effect of much faster heat transfer from the weld area and presence of diffusible hydrogen causing increased metal fragility. The paper evaluates the susceptibility to cold cracking of the high strength S355G10+N steel used, among others, for ocean engineering and hydrotechnical structures, which require underwater welding. It has been found from the CTS test results that the investigated steel is susceptible to cold cracking in the wet welding process.

  20. Effects of Nitrogen and Carbon on Mechanical Properties of Weld-Simulated 19% Chromium Steels

    OpenAIRE

    ShinIchiro, OCHIAI; Nobuhiro, SAITO; Yoneo, Kikuta; Department of Welding Engineering, Faculty of Engineering, Osaka University

    1980-01-01

    Poor toughnesses of welded high-chromium ferritic steels are due to the coarsened grain and the deteriorating effects of carbon and nitrogen impurities upon the intrinsically brittle b.c.c. materials. The control of these impurity elements is crucial for the improvement of the weldability and reduction of hot-cracking susceptibility. 19% chromium steels with various impurity levels of C : 10-800ppm and N : 30-740ppm, together with a commercial 19% Cr super ferritic, are high-temperature heat-...

  1. Wedlable nickel aluminide alloy

    Energy Technology Data Exchange (ETDEWEB)

    Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)

    2002-11-19

    A Ni.sub.3 Al alloy with improved weldability is described. It contains about 6-12 wt % Al, about 6-12 wt % Cr, about 0-3 wt % Mo, about 1.5-6 wt % Zr, about 0-0.02 wt % B and at least one of about 0-0.15 wt % C, about 0-0.20 wt % Si, about 0-0.01 wt % S and about 0-0.30 wt % Fe with the balance being Ni.

  2. Characterization of NiCrAlC PTA coatings

    OpenAIRE

    2012-01-01

    Surface tailoring with plasma transferred arc (PTA) hardfacing involves the deposition of powder mixtures to produce coatings with an almost unlimited chemical composition. PTA hardfacing is particularly important for processing low weldability alloys, such as those for high-temperature applications, of which NiCrAlC is an example. This study analyzed NiCrAlC coatings processed by PTA using a mixture of elemental powders. Deposition on AISI316L plates was carried out with currents of 100 A an...

  3. Experimental Determination of the Primary Solidification Phase dependency on the solidification velocity for 17 different austenitic stainless steel compositions

    DEFF Research Database (Denmark)

    Laursen, Birthe Nørgaard; Olsen, Flemming Ove; Yardy, John;

    1997-01-01

    to the austenite phase.Most stainless steels are weldable by conventional welding techniques. However, during laser weldng the solidification velocities can be very much higher than by conventional welding techniques. By increasing the solidification velocity to a critical value known as the transition velocity......, the primary solidification phase is found to change from ferrite to austenite.A novel laser remelting technique has been modified to enable the transition velocity for laser welded austenitic stainless steels to be deermined experimentally and on the basis of results from 17 different alloy compositions...... an equation for the calculation of the transition velocity from alloy composition is proposed....

  4. Development of matching filler metals for welding CB2 and first experience

    Energy Technology Data Exchange (ETDEWEB)

    Heuser, Herbert; Jochum, Claus; Kreuzer-Zagar, Dorothea [Boehler Schweisstechnik Deutschland GmbH, Hamm (Germany)

    2010-07-01

    This paper gives an overview about the properties of a new martensitic welding consumable which is matching to CB2, FB2, PB2. This material has been developed in the frame of COST 536 research program. Thermanit MTS 5 Co1 shows high strength properties with moderate toughness in the range about 40 J. The mechanical properties have been tested after different PWHT, the influence of Boron was evaluated with respect to weldability, creep strength and toughness. Creep tests are still running, up to now, the filler metal behaves as expected. (orig.)

  5. Friction Stir Welding of Zr_(55)Al_(10)Ni_5Cu_(30) Bulk Metallic Glass to Crystalline Aluminum

    Institute of Scientific and Technical Information of China (English)

    Zuoxiang Qin; Cuihong Li; Haifeng Zhang; Zhongguang Wang; Zhuangqi Hu; Zhiqiang Liu

    2009-01-01

    The Zr_(55)Al_(10)Ni_5Cu_(30) bulk metallic glass plate were successfully welded to crystalline aluminum plates by using a friction stir welding (FSW) method. The welded zone was examined. No defects, cracks or pores were observed and no other crystalline phases except for aluminum were found in the welded joint. The strength of the joint is higher than that of aluminum. The glassy phase in the stir zone keeps the amorphous state, showing a successful welding. The storage modulus softens over the glass transition. And the weldability was discussed according to this phenomena.

  6. MM98.89 Gleeblen - et værktøj til fysisk simulering

    DEFF Research Database (Denmark)

    Kristensen, Lars; Sørensen, Kirsten Grønning; Jensen, Carsten

    1999-01-01

    This article describes the construction and application of the thermo mechanical simulator, the Gleeble. The Gleeble is used for physical process simulation and material testing. Possible application areas are described and a specific example of weldability testing within the area of arc welding...... is described. The latest application of the Gleeble at the Department of Manufacturing Engineering, DTU; hot compression tests in order to achieve stress vs. strain curves as function of strainrate and temperature is presented. These results have been used as input in a FEM programme for simulation...... of projection welding...

  7. The interfacial structure of plated copper alloy resistance spot welded joint

    Science.gov (United States)

    Wu, Jingwei; Zhai, Guofu; Chen, Qing; Wang, Jianqi; Ren, Gang

    2008-09-01

    Plated copper alloys are widely used in electron industry. The plating lay caused the farther decreasing of the welding property of copper alloys, whose intrinsic weldability was poor. In this paper, the bronze and brass specimens with nickel-tin double plating layer were joined by resistance spot welding method. The microstructure and peel strength of the joints were investigated. The experiment results show that a sandwich-like structure was obtained in the faying surface after welding, and the nickel plating layer thickness had severe effect on the reliability of the joints.

  8. The interfacial structure of plated copper alloy resistance spot welded joint

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jingwei [Xiamen Hongfa Electroacoustic Co., Ltd, 361021 Xiamen (China); Harbin Institute of Technology, 150001 Harbin (China)], E-mail: jingweiwu.hit@gmail.com; Zhai Guofu [Harbin Institute of Technology, 150001 Harbin (China); Chen Qing; Wang Jianqi; Ren Gang [Xiamen Hongfa Electroacoustic Co., Ltd, 361021 Xiamen (China)

    2008-09-15

    Plated copper alloys are widely used in electron industry. The plating lay caused the farther decreasing of the welding property of copper alloys, whose intrinsic weldability was poor. In this paper, the bronze and brass specimens with nickel-tin double plating layer were joined by resistance spot welding method. The microstructure and peel strength of the joints were investigated. The experiment results show that a sandwich-like structure was obtained in the faying surface after welding, and the nickel plating layer thickness had severe effect on the reliability of the joints.

  9. Caracterización mecánica de aceros empleados en el sector de la construcción de Almería

    Directory of Open Access Journals (Sweden)

    Senoboua, A. J.

    2003-12-01

    Full Text Available Various tests have been conducted on the steel bars used in the construction of civil works in Almería (Spain during the period 18 January 2000-7 May 2001, with the aim of mechanically characterizing the different types of steel (weldable: B400S, B500S and ductile weldable: B400SD to determine whether there is a technical reason for the increase in the use of ductile weldable steel. For this, we have used a hydraulic machine to break by traction all the test samples that arrived to the laboratory, following the specifications of the UNE 7474-1:1992 and the UNE 7474-2:1992. The results indicate that only in 86 % of the cases does the steel B400SD satisfy the limits specified by the UNE 36065:1999-EX, as opposed to 95 and 94 % of the B400S and B500S steels. In addition, the ductile weldable steel registered mean values lower than those of B400S. This finding disagrees with expectations set by the specifications.

    Se realizaron varios ensayos sobre las barras de acero utilizadas en la construcción de obra civil en Almería, durante el período comprendido entre 18/1/2000 y 7/05/2001, con el fin de caracterizar, mecánicamente, los diferentes tipos de aceros (soldables: B400S, B500S y soldable dúctil: B400SD y, de esta forma, determinar si existe alguna razón técnica para un incremento del consumo del acero soldable dúctil. Para ello, se ensayaron a tracción todas las muestras que llegaron al laboratorio, siguiendo las normas UNE 7474-1:1992 y UNE 7474-2:1992. Los resultados indican que el acero B400SD cumple, sólo, en un 86 % los límites especificados en la norma UNE 36065:1999 -EX, frente al 95 y 94 % de los aceros B400S y B500S. Además, el acero soldable dúctil muestra unos valores medios inferiores al B400S. Este hecho discrepa de lo que se podría esperar según la norma que lo regula.

  10. Butt weld of aluminum alloy plates 6063 and LY12 by laser beam

    Science.gov (United States)

    Xia, Jin'an; Cheng, Zhaogu; Xu, Guoliang; Li, Xianqin

    2000-02-01

    By means of a transverse flow 5 kW CO2 laser with low- order mode laser beam output, 1 - 4 mm thick aluminum alloy plates 6063 and LY12 were successfully butt welded. The result shows that the butt weldability and the weld quality of the aluminum alloy plates are mainly dependent on incident laser power density, laser beam defocused distance and shielding gas. The relationship between the weld quality of the aluminum alloy plates and the welding parameters is discussed. The macrostructure and microstructure of the welded seams are analyzed. The mechanical properties of the welded seams are discussed.

  11. Failure Analysis of Electron Beam Weld Joints for 18Ni Co-free Maraging Steels

    Institute of Scientific and Technical Information of China (English)

    莫德锋; HU; Zheng-fei; WANG; Chun-xu; HE; Guo-qiu

    2007-01-01

    Microstructure of two different 18Ni Co-free maraging specimens and their electron beam weld joints were investigated comparatively by optical microscopy and SEM. It is showing that both of the steels are typical lath martensite, however, one grain size is about three times as another one, and XRD reveals that the amount of the retained austenitic phase in the former is less then the latter. The austenite distributes in plate form along granular and lath boundaries while some in fine particle within the matrix. The microstructural difference between two specimens led to diverse behaviors in electron beam welding. The first specimen is weldable well but the second shows obvious welding defects of pits and burn-through holes in weld face. The welding microstructure exhibits a typical dendritic morphology, and the grains in the heat-affected zone recrystallized and grew up obviously for high temperature heated by welding electron beam. The weldablity is relative to the thermal conduction performance of the base materials,which is contributed greatly for grain size and austenite content.

  12. Materials development for ITER shielding and test blanket in China

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.M., E-mail: Chenjm@swip.ac.cn [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Wu, J.H.; Liu, X.; Wang, P.H. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Wang, Z.H.; Li, Z.N. [Ningxia Orient Non-ferrous Metals Group Co. Ltd., P.O. Box 105, Shizuishan (China); Wang, X.S.; Zhang, P.C. [China Academy of Engineering Physics, P.O. Box 919-71, Mianyang 621900 (China); Zhang, N.M.; Fu, H.Y.; Liu, D.H. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China)

    2011-10-01

    China is a member of the ITER program and is developing her own materials for its shielding and test blanket modules. The materials include vacuum-hot-pressing (VHP) Be, CuCrZr alloy, 316L(N) and China low activation ferritic/martensitic (CLF-1) steels. Joining technologies including Be/Cu hot isostatic pressing (HIP) and electron beam (EB) weldability of 316L(N) were investigated. Chinese VHP-Be showed good properties, with BeO content and ductility that satisfy the ITER requirements. Be/Cu mock-ups were fabricated for Be qualification tests at simulated ITER vertical displacement event (VDE) and heat flux cycling conditions. Fine microstructure and good mechanical strength of the CuCrZr alloy were achieved by a pre-forging treatment, while the weldability of 316L(N) by EB was demonstrated for welding depths varying from 5 to 80 mm. Fine microstructure, high strength, and good ductility were achieved in CLF-1 steel by an optimized normalizing, tempering and aging procedure.

  13. Evaluation of HAZ liquation cracking susceptibility and HAZ softening behavior in modified 800H

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P. (Tennessee Univ., Knoxville, TN (United States). Dept. of Materials Science and Engineering)

    1992-11-20

    A modified 800H alloy, developed at Oak Ridge National Laboratory (ORNL), is one of the candidate materials designed for high temperature applications. Extensive mechanical and corrosion investigations have been completed and it has been proven that modified 800 has excellent high temperature mechanical and metallurgical behavior. Weldability studies of modified 800H are being carried out at the University of Tennessee, Knoxville. A series of modified 800H alloys and two similar commercial high temperature materials (310Ta and HR3C) were used to conduct this investigation. A preliminary weldability evaluation has been accomplished and the major part of the results (HAZ liquation cracking resistance and HAZ softening behavior in modified 800H) is addressed in this report. The basic conclusion of this investigation is that modified 800H material possesses good resistance to HAZ liquation cracking especially with a grain size control (thermo-mechanical treatment). The information from this study is important to the further modification of the material in order to extend its applications.

  14. New explosive welding technique to weld aluminum alloy and stainless steel plates using a stainless steel intermediate plate

    Energy Technology Data Exchange (ETDEWEB)

    Hokamoto, K.; Fujita, M. (Kumamoto Univ. (Japan). Dept. of Mechanical Engineering); Izuma, T. (Asahi Chemical Industry Co., Ltd., Siga (Japan))

    1993-10-01

    Various aluminum alloys and stainless steel were explosively welded using a thin stainless steel intermediate plate inserted between the aluminum alloy driver and stainless steel base plates. At first. the velocity change of the driver plate with flying distance is calculated using finite-difference analysis. Since the kinetic energy lost by collision affects the amount of the fused layer generated at the interface between the aluminum alloy and stainless steel, the use of a thin stainless steel intermediate plate is effective for decreasing the energy dissipated by the collision. The interfacial zone at the welded interface is composed of a fine eutectic structure of aluminum and Fe[sub 4]Al[sub 13], and the explosive welding, process of this metal combination proceeds mainly by intensive deformation of the aluminum alloy. The weldable region for various aluminum alloys is decided by the change in collision velocity and kinetic energy lost by collision, and the weldable region is decreased with the increase in the strength of the aluminum alloy.

  15. Effects of titanium and zirconium on iron aluminide weldments

    Energy Technology Data Exchange (ETDEWEB)

    Mulac, B.L.; Edwards, G.R. [Colorado School of Mines, Golden, CO (United States). Center for Welding, Joining, and Coatings Research; Burt, R.P. [Alumax Technical Center, Golden, CO (United States); David, S.A. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-12-01

    When gas-tungsten arc welded, iron aluminides form a coarse fusion zone microstructure which is susceptible to hydrogen embrittlement. Titanium inoculation effectively refined the fusion zone microstructure in iron aluminide weldments, but the inoculated weldments had a reduced fracture strength despite the presence of a finer microstructure. The weldments fractured by transgranular cleavage which nucleated at cracked second phase particles. With titanium inoculation, second phase particles in the fusion zone changed shape and also became more concentrated at the grain boundaries, which increased the particle spacing in the fusion zone. The observed decrease in fracture strength with titanium inoculation was attributed to increased spacing of second phase particles in the fusion zone. Current research has focused on the weldability of zirconium- and carbon-alloyed iron aluminides. Preliminary work performed at Oak Ridge National Laboratory has shown that zirconium and carbon additions affect the weldability of the alloy as well as the mechanical properties and fracture behavior of the weldments. A sigmajig hot cracking test apparatus has been constructed and tested at Colorado School of Mines. Preliminary characterization of hot cracking of three zirconium- and carbon-alloyed iron aluminides, each containing a different total concentration of zirconium at a constant zirconium/carbon ratio of ten, is in progress. Future testing will include low zirconium alloys at zirconium/carbon ratios of five and one, as well as high zirconium alloys (1.5 to 2.0 atomic percent) at zirconium/carbon ratios of ten to forty.

  16. 选区激光熔化TC4钛合金电子束焊接试验研究%Electron Beam Welding of Selective Laser Meltded TC4 Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    董鹏; 梁晓康; 陈济轮; 黑艳颖; 田彩兰

    2014-01-01

    初步研究了选区激光熔化成形TC4钛合金的电子束焊接性。试验采用中压电子束对4mm厚试片进行焊接。焊后采用光学显微镜、显微硬度计、拉伸试验机评价了接头的显微组织和力学性能。选区激光熔化TC4焊缝与板材焊缝类似,接头的抗拉强度为1278MPa,达到母材90%以上。%In this paper, the elctron beam weldability of selective laser meltded TC4 titanium alloys was investigated preliminarily. The optical microscope, microhardness and tensile test were used in analysted the characteristic of the elctron beam welded joint. The well electron beam weldability was shown from the analysis results. The tensile strengh of selective laser melted TC4 joints was 1278MPa.

  17. Investigations of Spot Weld Material Characterization for Hat Beam Component Impact Analysis

    Directory of Open Access Journals (Sweden)

    Sachin Patil

    2016-07-01

    Full Text Available With a greater emphasis placed on weight reduction the ground vehicle industry has increased the use of higher strength, thinner gage steels, particularly cold rolled high strength steels (HSS. Choice of a particular HSS will depend upon such factors as cost, formability, fatigue resistance and weldability, in particular spot weldability. Vehicle collision characteristics significantly influenced by spot welded joints in vehicle steel body components.In engineering practice, spot welds are normally not modeled in detail, but as connection elements which transfer forces and moments. Therefore a proper methodology for the development detailed weld model to study structural response of the weld when the applied load range is beyond the yield strength discussed in this paper. Three-dimensional finite element (FE models of spot welded joints are developed using LS-Dyna. Simple spot weld models are developed based on the detailed model behavior developed earlier. In order to generate testing data, virtual tensile testing simulations are carried out with mesh sensitivity in the necking zone. This high mesh resolution around necking zone is required to capture the steep gradients in the pressure and stress tri-axility, etc. Once the stress strain curve are generated in the simulations examined damage function and evolution to represent failure. Various EHSS steels grades used in this study. The results from this study shows reasonable agreement between the simulations and the test results. Hence, spot weld model obtained should be considered for crash analysis applications to understand behaviors of structural parts.

  18. The Microstructural Evolution of Vacuum Brazed 1Cr18Ni9Ti Using Various Filler Metals

    Directory of Open Access Journals (Sweden)

    Yunxia Chen

    2017-04-01

    Full Text Available The microstructures and weldability of a brazed joint of 1Cr18Ni9Ti austenitic stainless steel with BNi-2, BNi82CrSiBFe and BMn50NiCuCrCo filler metals in vacuum were investigated. It can be observed that an interdiffusion region existed between the filler metal and the base metal for the brazed joint of Ni-based filler metals. The width of the interdiffusion region was about 10 μm, and the microstructure of the brazed joint of BNi-2 filler metal was dense and free of obvious defects. In the case of the brazed joint of BMn50NiCuCrCo filler metal, there were pits, pores and crack defects in the brazing joint due to insufficient wettability of the filler metal. Crack defects can also be observed in the brazed joint of BNi82CrSiBFe filler metal. Compared with BMn50NiCuCrCo and BNi82CrSiBFe filler metals, BNi-2 filler metal is the best material for 1Cr18Ni9Ti austenitic stainless steel vacuum brazing because of its distinct weldability.

  19. Development of Fabrication Procedure and Welding Performance Test for ITER HCCR TBM

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. S.; Lee, E. H.; Kim, S. K.; Lee, D. W.; Shin, K. I.; Jin, H. G. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, S. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Korea has developed and plans to test a Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) in the ITER. The HCCR TBM is composed of four sub-modules and a back manipulator (BM). Each sub-module is composed of a first wall (FW), a breeding box with a seven-layer breeding zone (BZ), and side walls (SW) with a cooling path. The front surface of the sub-module is 231 mm in width and 835 mm in height. The test specimens of the ARAA were prepared to test the weldability for tungsten inert gas (TIG) welding and electron beam (EB) welding. To establish and optimize the welding procedure in an EB weld from ARRA material, the variation in the bead width and penetration depth according to the welding current and welding speed were investigated. To verify the weldability and fabrication procedure for a complex structure such as the breeding zone, a small box with a cooling channel is being fabricated using the ARAA steel under development. A fabrication procedure of a HCCR TBM submodule was designed for a first wall, breeding zone including the side wall, and assembled sub-module by welding the first wall and breeding zone box. A plate for the test specimen to evaluate the welding characteristics was fabricated based on the optimized E-beam welding results.

  20. Welding Behavior of Free Machining Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    BROOKS,JOHN A.; ROBINO,CHARLES V.; HEADLEY,THOMAS J.; MICHAEL,JOSEPH R.

    2000-07-24

    The weld solidification and cracking behavior of sulfur bearing free machining austenitic stainless steel was investigated for both gas-tungsten arc (GTA) and pulsed laser beam weld processes. The GTA weld solidification was consistent with those predicted with existing solidification diagrams and the cracking response was controlled primarily by solidification mode. The solidification behavior of the pulsed laser welds was complex, and often contained regions of primary ferrite and primary austenite solidification, although in all cases the welds were found to be completely austenite at room temperature. Electron backscattered diffraction (EBSD) pattern analysis indicated that the nature of the base metal at the time of solidification plays a primary role in initial solidification. The solid state transformation of austenite to ferrite at the fusion zone boundary, and ferrite to austenite on cooling may both be massive in nature. A range of alloy compositions that exhibited good resistance to solidification cracking and was compatible with both welding processes was identified. The compositional range is bounded by laser weldability at lower Cr{sub eq}/Ni{sub eq} ratios and by the GTA weldability at higher ratios. It was found with both processes that the limiting ratios were somewhat dependent upon sulfur content.

  1. Soldabilidad de las fundiciones de grafito esferoidal

    Directory of Open Access Journals (Sweden)

    Cembrero, J.

    2004-04-01

    Full Text Available Hereinafter it is analysed the weldability of a spheroidal graphite cast iron of a established chemical composition. Shielded metal-arc welding (SMAW have been used on casting samples of 300 x 90 x 10 mm, with a groove angle of 60º. It is also analysed the influence on the weldability of the chemical composition of the different electrodes used, Ni (56 % and 97,6 % each one as well as the influence of the pre-heating temperature ( 350 ºC and 600 ºC and the coldest velocity (at the air and at the furnace. The weldability is evaluated by tests of to bends and traction. Finally, microstructure analysis are performed on the joints: on the heat-affected-zone (the piece near the weld; the piece-weld interface; and the fusion-zone (the weld. Mechanical characteristics of the joint and its microstructure and with fractography analysis are correlated. In order to investigate the influence of the principal factors and interactions that take place in the process, a factorial design at two levels (high + and low - was used, what meant to carry out 8 experiences.

    En el presente trabajo se analiza la soldabilidad de una fundición de grafito esferoidal (F.G.E. de composición determinada, efectuando soldaduras por arco manual con electrodos revestidos, en probetas de esta fundición con dimensiones de 300 x 90 x 10 mm y ángulo de achaflanado de 60º. Se analiza la influencia en la soldabilidad de la composición de los distintos electrodos utilizados, base Ni (del 56 y 97,6 % respectivamente, la influencia de las temperaturas de precalentamiento (350 ºC y 600 ºC y de la velocidad de enfriamiento (al aire y en el horno. La soldabilidad se evalúa mediante los ensayos de doblado y tracción. Se hace un análisis microestructural de las uniones: en el material a unir próximo a la soldadura; en la interfase metal - soldadura; y en el propio cordón de soldadura. Se correlacionan las características resistentes de la unión con la microestructura y

  2. Corrosion resistance of high-performance materials titanium, tantalum, zirconium

    CERN Document Server

    2012-01-01

    Corrosion resistance is the property of a material to resist corrosion attack in a particular aggressive environment. Although titanium, tantalum and zirconium are not noble metals, they are the best choice whenever high corrosion resistance is required. The exceptionally good corrosion resistance of these high–performance metals and their alloys results from the formation of a very stable, dense, highly adherent, and self–healing protective oxide film on the metal surface. This naturally occurring oxide layer prevents chemical attack of the underlying metal surface. This behavior also means, however, that high corrosion resistance can be expected only under neutral or oxidizing conditions. Under reducing conditions, a lower resistance must be reckoned with. Only very few inorganic and organic substances are able to attack titanium, tantalum or zirconium at ambient temperature. As the extraordinary corrosion resistance is coupled with an excellent formability and weldability these materials are very valua...

  3. Multiscale Modelling: the role of helium in iron

    Directory of Open Access Journals (Sweden)

    Maria Samaras

    2009-11-01

    Full Text Available The mechanisms and processes of bubble nucleation and growth are still not completely solved and research in this field is ongoing. This is an important issue for materials used in fission and fusion reactors. In such environments, one of the main gaseous by-products is helium, whose presence and further production is known to decrease ductility, fatigue life and weldability, induce creep and stress rupture properties of materials, as well as promote swelling. These effects lead to the drastic modification of the material's mechanical properties. In the past, experiments have been used to offer clues into the structure of the materials; now, modelling offers the possibility to understand the structure of the material and from this information, to elucidate a fundamental understanding of material properties. This review discusses the modelling paradigms used to investigate and obtain an understanding of the mechanisms at play in helium bubble nucleation and growth in ferritic steels.

  4. Photoemission Electron Microscopy as a Tool for Studying Steel Grains

    Science.gov (United States)

    Roese, Peter; Keutner, Christoph; Berges, Ulf; Espeter, Philipp; Westphal, Carsten

    2017-03-01

    Key properties of steel like stability, weldability, or ability for absorbing deformation energy are defined by their grain structure. The knowledge about their micrometer and submicrometer structure is of particular interest for tailor-cut macroscopic steel properties. We report on photoemission electron microscopy studies which in principle yield a higher magnification than comparable optical techniques. A flat surface without any topographic features was obtained by applying a non-etching preparation procedure. PEEM images showed very tiny phase islands embedded within a steel phase matrix. Furthermore, we developed an analysis procedure for PEEM images for dual-phase steels. As a result, it is possible to identify the individual work functions of different steel phases at the surface.

  5. Computational thermodynamics, Gaussian processes and genetic algorithms: combined tools to design new alloys

    Science.gov (United States)

    Tancret, F.

    2013-06-01

    A new alloy design procedure is proposed, combining in a single computational tool several modelling and predictive techniques that have already been used and assessed in the field of materials science and alloy design: a genetic algorithm is used to optimize the alloy composition for target properties and performance on the basis of the prediction of mechanical properties (estimated by Gaussian process regression of data on existing alloys) and of microstructural constitution, stability and processability (evaluated by computational themodynamics). These tools are integrated in a unique Matlab programme. An example is given in the case of the design of a new nickel-base superalloy for future power plant applications (such as the ultra-supercritical (USC) coal-fired plant, or the high-temperature gas-cooled nuclear reactor (HTGCR or HTGR), where the selection criteria include cost, oxidation and creep resistance around 750 °C, long-term stability at service temperature, forgeability, weldability, etc.

  6. Mechanical Properties and Microstructures of the HAZs of 11Cr F/M Steel for Gen-IV Nuclear Power Station

    Science.gov (United States)

    Li, Yongkui; Wang, Jian; Lu, Shanping; Rong, Lijian; Li, Dianzhong

    2015-02-01

    The weldability of a newly developed 11Cr ferritic/martensitic (F/M) steel to be used in Pb-Bi liquid cooled ADS for the fourth generation nuclear power station was studied by experiments and numerical simulation. In this work, an appropriate method for obtaining simulated heat-affected zones (HAZs) was developed. HAZs, including CG-HAZ, FG-HAZ, and IC-HAZ, were successfully simulated by Gleeble at heating rates of 209, 176, and 149 °C/s and peak temperatures of 1314, 1138, and 998 °C, respectively. Results of tension and impact tests indicated that the simulated HAZs had much higher strength and poorer toughness than the base metal. The poor toughness is caused by high carbon, silicon contents, and quenched martensitic microstructures. The tempering treatment is necessary for the developed steel before application in nuclear reactor.

  7. Evaluation of Cracking Resistance of Copper-Bearing Age Hardening Steel Weldment

    Institute of Scientific and Technical Information of China (English)

    CHAI Feng; YANG Cai-fu; SU Hang; ZHANG Yong-quan; XU Zhou

    2007-01-01

    The weldability of a low-carbon copper-bearing age hardening steel was evaluated using cracking susceptibility calculation, HAZ maximum hardness measurement, and Y-groove cracking evaluation test. The results show that the hardenability characteristics and cold cracking susceptibility of the steel are very low. The results also indicate that a crack-free weldment can be obtained during the welding of this type of steel even at an ambient temperature as low as -5 ℃ as well as in an absolute humidity lower than 4 000 Pa without any preheat treatment. A slight preheat treatment can prevent the joint from cracking when welding is carried out at lower ambient temperature or higher absolute humidity.

  8. Investigations on the microstructure and mechanical properties of multi-pass PCGTA welding of super-duplex stainless steel

    Indian Academy of Sciences (India)

    K Devendranath Ramkumar; Debidutta Mishra; G Thiruvengatam; S P Sudharsan; Tadikonda Harsha Mohan; Vimal Saxena; Rachit Pandey; N Arivazhagan

    2015-08-01

    This paper addresses the weldability, microstructure and mechanical properties of the multi-pass welding of super-duplex stainless steel (SDSS). Pulsed current gas tungsten arc welding (PCGTAW) was carried out employing ER2553 and ERNiCrMo-4 fillers. Microstructure examination showed the presence of austenite in different forms at the weld zone of ER2553 whereas multi-directional grain growth was observed for ERNiCrMo-4 welds. Tensile and impact studies corroborated that the weldments employing ER2553 exhibited better results compared with ERNiCrMo-4 weldments. Detailed structure–property relationships of the weldments have been reported in the present study. The results corroborated that the enhanced properties could be achieved with the matching filler wire compared with the over-alloyed filler.

  9. Investigation on the Interface Morphologies of Explosive Welding of Inconel 625 to Steel A516 Plates

    Science.gov (United States)

    Mousavi, S. A. A. Akbari; Zareie, H. R.

    2011-01-01

    The purpose of this study is to produce composite plates by explosive cladding process. This is a process in which the controlled energy of explosives is used to create a metallic bond between two similar or dissimilar materials. The welding conditions were tailored through parallel geometry route with different operational parameters. In this investigation, a two-pronged study was adopted to establish the conditions required for producing successful solid state welding: (a) Analytical calculations to determine the weldability domain or welding window; (b) Metallurgical investigations of explosive welding experiments carried out under different explosive ratios to produce both wavy and straight interfaces. The analytical calculations confirm the experimental results. Optical microscopy studies show that a transition from a smooth to wavy interface occurs with an increase in explosive ratio. SEM studies show that the interface was outlined by characteristic sharp transition between two materials.

  10. Experimental investigation of explosive welding of cp-titanium/AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Akbari Mousavi, S.A.A. [School of Metallurgy and Materials Engineering, University College of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran (Iran, Islamic Republic of)], E-mail: akbarimusavi@ut.ac.ir; Farhadi Sartangi, P. [School of Metallurgy and Materials Engineering, University College of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran (Iran, Islamic Republic of)], E-mail: farhadi_pezhman@engmail.ut.ac.ir

    2009-03-15

    In explosive welding process, the controlled energy of explosives is used to create a metallurgical bond between two similar or dissimilar materials. This paper presents the analytical calculation for determination of weldability domain or welding window. The analytical calculations are in good agreement with experimental results. The welding conditions are tailored through parallel geometry route with different explosive loads. The study was also conducted to consider the effects of explosive loading on the bonding interface and the characterization of explosive welding experiments carried out under different conditions. Optical microscopy studies show that a transition from a smooth interface to a wavy one occurs with increase in explosive load. Scanning electron microscopy studies show that the interface was outlined by characteristic sharp transition between two materials, but local melted zones were also encountered in the front slope of waves in the interface at high explosive loads. XRD studies detected no intermetallic phases for specimen welded at low explosive load.

  11. Influence of austenisation temperature and hold time on grain size of type 9Cr1MoVNb ferritic-martensitic steels used in supercritical boilers; Influencia de la temperature de austenizacion y tiempo de permanencia sobre el tamano de grano en aceros ferritico-martensiticos del tipo 9Cr1MoVNb utilizados en calderas supercriticas

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Urrutia, I.; Gutierrez, S.; San Juan, J. M.

    2001-07-01

    The aim of the present work is to determine the influence of asutenitizing temperature holding time and heating velocity on grain size of ferritic-martensitic type 9Cr1MoVNb steels developed for Oak Ridge National Laboratories & Combustion Engineering, T91/P91 Steels (USA) and X10CrMoVNb 9.1 (Europe). The potential benefits of this materials, in term of high resistance, good ductily and oxidation resistance, weldability and in particular good high temperature creep strength, are now widely acknowledged, particulary by supercritical boilers (P=300 bar, T=550{+-}50 degree centigree). The studied steels have been produced in, high frequency induction vacum furnaces and hot-rolled. (Author) 12 refs.

  12. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, modified alloy 800, and two sulfidation resistant alloys: HR160 and HR120. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700{degrees}C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925{degrees}C with good weldability and ductility.

  13. Effect of Microstructural changes on Mechanical properties of Friction stir welded Nano SiC reinforced AA6061composite

    Directory of Open Access Journals (Sweden)

    GOVIND.NANDIPATI

    2010-11-01

    Full Text Available Aluminum alloys used in aircrafts generally exhibit low weldability on fusion welding techniques. Friction stir welding (FSW has got a lot of attention as a solid state joining technique and provided an improved way of producing aluminum joints in a faster way. In the present work, nano Silicon carbide(SiC particles reinforced aluminum AA6061metal matrix composites which find applications in aircrafts are casted and friction stir welded. FSW resulted in significant grain refinement and homogeneous distribution of nano SiC particles. The Microstructural analysis is carried out using optical microscopy(OM and Scanning Electron Microscopy (SEM.The joint strength is increased compared to the conventional fusion welding techniques. The relationship between mechanical properties [hardness, UTS, Y.S] and microstructure of the welded region are studied.

  14. Tribological Investigations of Hard-Faced Layers and Base Materials of Forging Dies with Different Kinds of Lubricants Applied

    Directory of Open Access Journals (Sweden)

    V. Lazić

    2010-12-01

    Full Text Available This paper gives a procedure for choosing the right technology for reparative hard facing of damaged forging dies. Since they are subject to impact loads and cyclic temperature elevations, forging dies should be made of steel that is able to withstand great impact loads, maintain good mechanical properties at elevated temperatures and that is resistant to wear and thermal fatigue. For these reasons, forging dies are made of conditionally weldable alloy tool steels; however it makes hard facing of damaged tools even more difficult. In this paper, wear resistance of base materials, hard-faced layers and heat-affected zones are tribologically investigated when two different lubricants - pure synthetical oil LM 76 and LM 76 with 6% molybdenum disulfide (MoS2 are applied. Tribological investigations have shown that the wear resistance of the hard faced layers is considerably greater than the wear resistance of the base material. However, the base material has better properties concerning friction.

  15. Finite element modeling and analysis of electro-magnetic pulse welding of aluminium tubes to steel bars

    Science.gov (United States)

    Kumar, Ramesh; Doley, Jyoti; Kore, Sachine

    2016-10-01

    Magnetic pulse welding is a high-speed, solid-state welding process that is applicable to sheets or tube-to-tube or tube-to-bar configurations. In this article we discuss about the MPW process modeling and simulation for welding Al tubes to steel bars. Finite element simulation was done to weld 6061 Al tubes of 1.65 mm wall thickness to 1010 steel bars of a 47.6 mm nominal diameter. Simulation results indicate that Al tubes can be successfully welded to steel bars using MPW. It is found that the standoff distance between the Al tube and the steel bar i.e. gap between inner diameter of Al tube and diameter of steel bar is a dominant factor for achieving a sound weld. The addition of receding angles to the bars can promote MPW weldability window.

  16. Ultrasonic Welding of Wires and Cables

    Science.gov (United States)

    Heinz, Stefan; Wagner, Guntram; Eifler, Dietmar

    2012-03-01

    In the automobile industry, ultrasonic metal welding is an established method. At the Institute of Materials Science and Engineering (WKK) at the University of Kaiserslautern, Germany, systematic investigations of the weldability of Al-wires and flat flexible copper cables were carried out. In the case of Al-wires, joints with cross-sectional area of up to 80 mm2 and tensile shear load of about 3500 N were finally realized. Furthermore, methods to reduce unintentional adherence between the sonotrode coupling face and the Al-wires were developed. To realize FFC joints, ultrasonic spot welding systems and ultrasonic torsion welding systems were used. A central purpose of these investigations is the development of a system to enable welding through the insulation of the FFC without weakening the base material.

  17. Corrosion performance of martensitic stainless steel seamless pipe for linepipe application

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Mitsuo; Miyata, Yukio; Toyooka, Takaaki; Murase, Fumio [Kawasaki Steel Corp., Handa, Aichi (Japan)

    1999-11-01

    The corrosion performance of two types of weldable martensitic stainless steel seamless pipe for pipeline application is investigated. 11Cr steel pipe developed for sweet environment gives better resistance to CO{sub 2} corrosion than the 13Cr martensitic stainless steel for OCTG. 12Cr steel pipe developed for light sour environment shows good SSC resistance in a mild sour environment and superior CO{sub 2} corrosion resistance at high temperature and high CO{sub 2} partial pressure condition. The suitable condition for the 11Cr steel pipe and the 12Cr steel pipe in sweet environment, and the critical pH and H{sub 2}S partial pressure for the 12Cr steel pipe welded joint in sour environment are clarified. Both welded joints have superior resistance to hydrogen embrittlement under the cathodic protection condition in sea water.

  18. Influence of the Surface Layer when the CMT Process Is Used for Welding Steel Sheets Treated by Nitrooxidation

    Directory of Open Access Journals (Sweden)

    I. Michalec

    2012-01-01

    Full Text Available Nitrooxidation is a non-conventional surface treatment method that can provide significantly improved mechanical properties as well as corrosion resistance. However, the surface layer is a major problem during the welding process, and welding specialists face many problems regarding the weldability of steel sheets. This paper deals with the properties of a nitrooxidized surface layer, and evaluates ways of welding steel sheets treated by nitrooxidation using a Cold Metal Transfer (CMT process. The limited heat input and the controlled metal transfer, which are considered as the main advantage of the CMT process, have a negative impact on weld joint quality. An excessive amount of porosity is observed,probably due to the high content of nitrogen and oxygen in the surface layer of the material and the fast cooling rate of the weld pool.

  19. An investigation of abrasive wear and corrosion behavior of surface repair of gray cast iron by SMAW

    Directory of Open Access Journals (Sweden)

    Alireza Sadeghi

    2017-01-01

    Full Text Available In this work, improving the abrasion–corrosion behavior of gray cast iron used in centrifugal pumps was studied. These pumps are usually made of gray cast iron (BS:1452Gr220 and are repaired by Shielded Metal Arc Welding (SMAW. Three different typical welding electrodes including Ni electrode (DIN8563, Carbon Steel electrode (DIN1913, and Hardening electrode (DIN8555 were used to compare the weldability of the base metal. Microstructural differences for three types of electrodes were studied and forming of different phases was analyzed. Corrosion and abrasion tests were conducted and related to welding conditions. Experimental results showed that using Ni substrate electrode reduce the unwanted phases (martensitic and carbides. Furthermore, in comparison with the base metal, the abrasion behavior of all weldments was improved. It was also determined that the carbon steel electrode has a higher corrosion resistance in zero-resistance ammeter (ZRA test compared to other electrodes.

  20. Long-term creep rupture strength of weldment of Fe-Ni based alloy as candidate tube and pipe for advanced USC boilers

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Gang; Sato, Takashi [Babcok-Hitachi K.K., Hiroshima (Japan). Kure Research Laboratory; Marumoto, Yoshihide [Babcok-Hitachi K.K., Hiroshima (Japan). Kure Div.

    2010-07-01

    A lot of works have been going to develop 700C USC power plant in Europe and Japan. High strength Ni based alloys such as Alloy 617, Alloy 740 and Alloy 263 were the candidates for boiler tube and pipe in Europe, and Fe-Ni based alloy HR6W (45Ni-24Fe-23Cr-7W-Ti) is also a candidate for tube and pipe in Japan. One of the Key issues to achieve 700 C boilers is the welding process of these alloys. Authors investigated the weldability and the long-term creep rupture strength of HR6W tube. The weldments were investigated metallurgically to find proper welding procedure and creep rupture tests are ongoing exceed 38,000 hours. The long-term creep rupture strengths of the HST weld joints are similar to those of parent metals and integrity of the weldments was confirmed based on with other mechanical testing results. (orig.)

  1. Process Simulation of Resistance Weld Bonding and Automotive Light-weight Materials

    DEFF Research Database (Denmark)

    Zhang, Wenqi; Chergui, Azeddine; Nielsen, Chris Valentin

    and predicting welding process window, for weld planning with optimal welding parameter settings, and for modeling microstructures and hardness distribution after welding. Latest developments have been made on simulation of resistance welding with nonconductive materials for applications in weld bonding......This paper presents the latest developments in numerical simulation of resistance welding especially with the new functions for simulation of microstructures, weld bonding and spot welding of new light-weight materials. The fundamental functions in SORPAS® are built on coupled modeling...... of mechanical, electrical, thermal and metallurgical processes, which are essential for simulation of resistance welding process to predict the welding results and evaluate the weldability of materials. These functions have been further extended with new functions for optimization of welding process parameters...

  2. Investigations of microstructures and properties in electron beam welded joints of TiAl to TC4

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The normally centered electron beam and non-centered electron beam welding of TiAl to TC4 was investigated in order to analyze the electron beam weldability between TiAl/TC4 dissimilar materials. Macroscopic cold crack easily occurred near TiAl substrate in the joints. The optimal tensile strength was related to the welding heat input. The weld structures were composed of bulky columnar grains and equiaxed grains. The isolated phases consisted of large quantities of α2-Ti-3Al phase, small quantity of B2 phase,γ-TiAl phase and YAl2 phase. Insufficient melting of the base metal occurred in the weld when the beam position leaned to the TC4 side. The tensile strength could be improved when the deflection was limited in the optimum range. Otherwise, non-fusion zone was easily generated in the weld, which led to the low tensile strength.

  3. Properties and Microstructure of Laser Welded VM12-SHC Steel Pipes Joints

    Directory of Open Access Journals (Sweden)

    Skrzypczyk A.

    2016-06-01

    Full Text Available Paper presents results of microstructure and tests of welded joints of new generation VM12-SHC martensitic steel using high power CO2 laser (LBW method with bifocal welding head. VM12-SHC is dedicated to energetic installation material, designed to replace currently used. High content of chromium and others alloying elements improve its resistance and strength characteristic. Use of VM12-SHC steel for production of the superheaters, heating chambers and walls in steam boilers resulted in various weldability researches. In article are presented results of destructive and non-destructive tests. For destructive: static bending and Vickers hardness tests, and for non-destructive: VT, RT, UT, micro and macroscopic tests were performed.

  4. Studies of Hot Crack Properties of Laser Welded Stainless Steel

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther

    During the present work crack testing concerning small and fast solidifying laser welds in austenitic stainless steel has been studied. A set of methods has been applied to investigate alloy properties, including ·Application of known information to predict solidification phases from the alloy...... composition. ·Weld metal solidification rate measurements for prediction of phases. ·Various crack tests to assess the crack susceptibility of alloys. ·A combination of the above for selection of suitable, weldable alloys. The possibility of using such specific methods for alloys and applications has been...... investigated and recommendations are given. From studies of literature it is found that the austenitic stainless steels have lowest crack susceptibility by a solidification course leaving approximately 15% rest ferrite in the weld metal. The alloys properties and the solidification rate determines the amount...

  5. The influence of electric ARC activation on the speed of heating and the structure of metal in welds

    Directory of Open Access Journals (Sweden)

    Savytsky Oleksandr M.

    2016-01-01

    Full Text Available This paper presents the results of a research related to the impact of electric arc activation onto drive welding energy and metal weld heating speed. It is confirmed that ATIG and AMIG methods, depending on metal thickness, single pass weldability and chemical composition of activating flux, enable the reduction of welding energy by 2-6 times when compared to conventional welding methods. Additionally, these procedures create conditions to increase metal weld heating speed up to 1,500-5,500°C/s-1. Steel which can be rapidly heated, allows for a hardened structure to form (with carbon content up to 0.4%, together with a released martensitic structure or a mixture of bainitic-martensitic structures. Results of the research of effectiveness of ATIG and AMIG welding showed that increase in the penetration capability of electric arc, which increases welding productivity, is the visible side of ATIG and AMIG welding capabilities.

  6. Rare Earth Additions in Continuously Cast Steel

    Science.gov (United States)

    Wilson, William G.; Heaslip, L. J.; Sommerville, I. D.

    1985-09-01

    Rare earth (lanthanide metals) addiiions to continuously cast steel are particularly advantageous because of their ability to refine as-cast structures, reduce segregation and increase hot ductility at temperatures just below that of solidification. The complete shape control of sulfides in steels containing Rare Earth Metals (REM), whether continuously cast or ingot cast, is primarily responsible for improvements in ductility related mechanical properties, weldability, fatigue resistance and resistance to hydrogen damage. Complete sulfide shape control can be obtained with REM additions at sulfur levels as high as.020%. The greatest improvements, however, are obtained with REM additions to low sulfur steels. However, to achieve full operational advantages afforded by REM, nozzle blockage problems must be circumvented. Water model studies indicate a possible solution.

  7. Friction welding of TiAl intermetallics and structural steel by applying Inconel 718 as interlayer

    Institute of Scientific and Technical Information of China (English)

    Li Jinglong; Wang Zhongping; Xiong Jiangtao; Zhang Fusheng; Wang Yanfang

    2005-01-01

    lnconel 718 with thickness ranged from 0. 1 - 1.7 mm was chosen as interlayer to promote weldability in friction welding of TiAl intermetallics and structural steel such as AISI 4140, in which the welded joint presents single fin showing less welding deformation on TiAl side. The correlations between tensile strength and the interlayer thickness were analyzed and fitted to a model. It indicates an optimum interlayer thickness ranged from 0. 9 - 1.1 mm where the tensile strength reaches as high as 360 MPa. Otherwise, while the interlayer thickness decreases to 0. 1 mm, brittle compounds of TiC, Al2 Ti4 C2 and M7 C3 are formed in the welded zone so that the tensile strength decays. Thicker interlayer should be also avoided as double joints may occur at TiAl - Inconel 718 and Inconel 718 -AISI 4140, respectively, which lowers the tensile strength to some extent.

  8. Simulation on temperature field of TIG welding of copper without preheating

    Institute of Scientific and Technical Information of China (English)

    LEI Yu-cheng; YU Wen-xia; LI Cai-hui; CHENG Xiao-nong

    2006-01-01

    According to the conservation of energy principle and technology characteristics of tungsten inert gas(TIG), a model of non-steady three-dimensional temperature field for red copper's TIG welding with a locomotive arc was established. The temperature field of welding pool was calculated with finite element software ANSYS. Indrafted the heat enthalpy conception and the surface distribution dual-ellipsoid model, the demands of welding numerical simulation was primely satisfied. Aimed at bad weldability of red copper, the TIG welding of thick-wall red copper was studied adopting Ar+N2 without preheating. The results show that the heating effect of arc is evidently enhanced, it is viable to achieve the no preheating TIG welding of red copper. Comparing the experimental values with the calculated ones under different technological parameters, the results indicate that the model and practical course are well matched, which proves that the model is reliable and correct.

  9. MM99.81 Projection welding of complex geometries

    DEFF Research Database (Denmark)

    Kristensen, Lars

    The objective of this work has been to establish a profound knowledge about design rules for projection welding geometries dependent of the actual material combination.Design rules and recommendations for geometries and projections in projection welding given in literature is summarised...... and these are catalogued into geometry-classes. A simulation software, SORPAS, based on the finite element method (FEM) is chosen as tool to investigate projection weld quality. SORPAS needs input of the material flow stress as function of strain, strain rate and temperature. Flow stress experiments are performed using...... been investigated.Two different welding geometries, disc with triangular ring projection welded to ring and hat welded to inside hole in ring, are both experimentally and numerically used to investigate the influence of different geometric parameters (thicknesses and angles) on weldability and weld...

  10. Three-Sheet Spot Welding of Advanced High-Strength Steels

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Friis, Kasper Storgaard; Zhang, W.

    2011-01-01

    The automotive industry has introduced the three-layer weld configuration, which represents new challenges compared to normal two-sheet lap welds. The process is further complicated by introducing high-strength steels in the joint. The present article investigates the weldability of thin, low....... The weld mechanisms are analyzed numerically and compared with metallographic analyses showing how the primary bonding mechanism between the thin, low-carbon steel sheet and the thicker sheet of high-strength steel is solid-state bonding, whereas the two high-strength steels are joined by melting, forming...... a weld nugget at their mutual interface. Despite the absence of the typical fusion nugget through the interface between the low-carbon steel and high-strength steel, the weld strengths obtained are acceptable. The failure mechanism in destructive testing is ductile fracture with plug failure....

  11. Predicting effects of diffusion welding parameters on welded joint properties by artificial neural network

    Institute of Scientific and Technical Information of China (English)

    刘黎明; 祝美丽; 牛济泰; 张忠典

    2001-01-01

    The static model for metal matrix composites in diffusion welding was established by means of artificial neural network method. The model presents the relationship between weld joint properties and welding parameters such as welding temperature, welding pressure and welding time. Through simulating the diffusion welding process of SiCw/6061Al composite, the effects of welding parameters on the strength of welded joint was studied and optimal technical parameters was obtained. It is proved that this method has good fault-tolerant ability and versatility and can overcome the shortage of the general experiment. The established static model is in good agreement with the actual welding process, so it becomes a new path for studying the weldability of new material.

  12. Modelling the Thermomechanical Conditions in Friction Stir Welding

    DEFF Research Database (Denmark)

    Schmidt, Henrik Nikolaj Blich

    Friction Stir Welding is a solid-state welding process invented by TWI in 1991. The FSW process is unique in the sense that joining of un-weldable alloys readily can be made. The thermomechanical conditions present in the workpiece during the welding process are of great interest since...... these control the properties of the weld. In the present work, a set of experimental, analytical and numerical analyses are carried out in order to evaluate the thermomechanical conditions descriptive for welding of aluminium, in this case AA2024-T3, under a specific set of welding parameters. Despite...... these specific data, the developed models can be applied for other alloys and welding parameters as well. A detailed experiment is carried out which constitutes the basis for the development and validation of the numerical and analytical models presented in this work. The contact condition at the tool...

  13. A Composite Steel Plate Shear Walls for Offshore Constructions

    Directory of Open Access Journals (Sweden)

    Badri Albarody Thar M.

    2014-07-01

    Full Text Available A new-type of weldable composite steel plate shear wall, which consists of a steel plate sandwiched by either of two or one composite panels at each side or at one side, has been proposed. An analytical model for such shear wall – via shell model is derived and the vibrational modes are discussed. Truss reinforcement is used to increase the integration between the steel and composite layers and the cross sectional properties were graded by magnetic nanoparticles fillers. The thickness shear modes at the composite wall appear higher than those of thickness stretch modes, but they are varied in a very orderly manner with respect to the vibrational mode. Also, some of characteristics are examined.

  14. Investigation of austenitic alloys for advanced heat recovery and hot-gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, and modified alloy 800. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700 C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925 C with good weldability and ductility.

  15. Testing of New Materials and Computer Aided Optimization of Process Parameters and Clamping Device During Predevelopment of Laser Welding Processes

    Science.gov (United States)

    Weidinger, Peter; Günther, Kay; Fitzel, Martin; Logvinov, Ruslan; Ilin, Alexander; Ploshikhin, Vasily; Hugger, Florian; Mann, Vincent; Roth, Stephan; Schmidt, Michael

    The necessity for weight reduction in motor vehicles in order to save fuel consumption pushes automotive suppliers to use materials of higher strength. Due to their excellent crash behavior high strength steels are increasingly applied in various structures. In this paper some predevelopment steps for a material change from a micro alloyed to dual phase and complex phase steels of a T-joint assembly are displayed. Initially the general weldability of the materials regarding pore formation, hardening in the heat affected zone and hot cracking susceptibility is discussed. After this basic investigation, the computer aided design optimization of a clamping device is shown, in which influences of the clamping jaw, the welding position and the clamping forces upon weld quality are presented. Finally experimental results of the welding process are displayed, which validate the numerical simulation.

  16. Fracture mechanics evaluation for at typical PWR primary coolant pipe

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T. [Kansai Electric Power Company, Osaka (Japan); Shimizu, S.; Ogata, Y. [Mitsubishi Heavy Industries, Ltd., Kobe (Japan)

    1997-04-01

    For the primary coolant piping of PWRs in Japan, cast duplex stainless steel which is excellent in terms of strength, corrosion resistance, and weldability has conventionally been used. The cast duplex stainless steel contains the ferrite phase in the austenite matrix and thermal aging after long term service is known to change its material characteristics. It is considered appropriate to apply the methodology of elastic plastic fracture mechanics for an evaluation of the integrity of the primary coolant piping after thermal aging. Therefore we evaluated the integrity of the primary coolant piping for an initial PWR plant in Japan by means of elastic plastic fracture mechanics. The evaluation results show that the crack will not grow into an unstable fracture and the integrity of the piping will be secured, even when such through wall crack length is assumed to equal the fatigue crack growth length for a service period of up to 60 years.

  17. Precipitation-strengthening effects in iron-aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, P.J.; McKamey, C.G.; Goodwin, G.M. [Oak Ridge National Laboratory, TN (United States)] [and others

    1995-05-01

    The purpose of this work is to produce precipitation to improve both high-temperature strength and room-temperature ductibility in FeAl-type(B2 phase) iron-aluminides. Previous work has focused on primarily wrought products, but stable precipitates can also refine the grain size and affect the properties of as-cast and/or welded material as well. New work began in FY 1994 on the properties of these weldable, strong FeAl alloys in the as-cast condition. Because the end product of this project is components for industry testing, simpler and better (cheaper, near-net-shape) processing methods must be developed for industrial applications of FeAl alloys.

  18. submitter Physical Properties of a High-Strength Austenitic Stainless Steel for the Precompression Structure of the ITER Central Solenoid

    CERN Document Server

    Sgobba, Stefano; Arauzo, Ana; Roussel, Pascal; Libeyre, Paul

    2016-01-01

    The ITER central solenoid (CS) consists of six independent coils kept together by a precompression support structure that must react vertical tensile loads and provide sufficient preload to maintain coil-to-coil contact when the solenoid is energized. The CS precompression system includes tie plates, lower and upper key blocks, load distribution and isolation plates and other attachment, support and insulating hardware. The tie plates operating at 4 K are manufactured starting from forgings in a high-strength austenitic stainless steel (FXM-19) with a stringent specification. Moreover, forged components for the lower and upper key blocks have to be provided in the same FXM-19 grade with comparably strict requirements. FXM-19 is a high-nitrogen austenitic stainless steel, featuring high strength and toughness, ready weldability, and forgeability. It features as well higher integral thermal contraction down to 4 K compared with the very high Mn steel grade selected for the CS coil jackets, hence providing an ad...

  19. Fatigue in Welded High-Strength Steel Plate Elements under Stochastic Loading

    DEFF Research Database (Denmark)

    Agerskov, Henning; Petersen, R.I.; Martinez, L. Lopez

    1999-01-01

    The present project is a part of an investigation on fatigue in offshore structures in high-strength steel. The fatigue life of plate elements with welded attachments is studied. The material used has a yield stress of ~ 810-840 MPa, and high weldability and toughness properties. Fatigue test...... series with constant amplitude loading and with various types of stochastic loading have been carried through on test specimens in high-strength steel, and - for a comparison - on test specimens in conventional offshore structural steel with a yield stress of ~ 400-410 MPa.A comparison between constant...... amplitude and variable amplitude fatigue test results shows shorter fatigue lives in variable amplitude loading than should be expected from the linear fatigue damage accumulation formula. Furthermore, in general longer fatigue lives were obtained for the test specimens in high-strength steel than those...

  20. Development of low-temperature high-strength integral steel castings for offshore construction by casting process engineering

    Directory of Open Access Journals (Sweden)

    Lim Sang-Sub

    2014-12-01

    Full Text Available In casting steels for offshore construction, manufacturing integral casted structures to prevent fatigue cracks in the stress raisers is superior to using welded structures. Here, mold design and casting analysis were conducted for integral casting steel. The laminar flow of molten metal was analyzed and distributions of hot spots and porosities were studied. A prototype was subsequently produced, and air vents were designed to improve the surface defects caused by the release of gas. A radiographic test revealed no internal defects inside the casted steel. Evaluating the chemical and mechanical properties of specimens sampled from the product revealed that target values were quantitatively satisfied. To assess weldability in consideration of repair welding, the product was machined with grooves and welded, after which the mechanical properties of hardness as well as tensile, impact, and bending strengths were evaluated. No substantive differences were found in the mechanical properties before and after welding.

  1. An investigation on fatigue in high-strength steel offshore structures

    DEFF Research Database (Denmark)

    Agerskov, Henning; Petersen, R.I.; Martinez, L. Lopez

    1998-01-01

    The fatigue life of offshore steel structures in high-strength steel is studied. The material used has a yield stress of 800-1000 MPa and high weldability and toughness properties. Of special interest is the fatigue life under a realistic stochastic loading. In the experimental part...... of the investigation, fatigue test series were carried out on both full scale tubular joints and smaller welded plate test specimens in high-strength steel as well as in conventional offshore structural steel. This paper gives a summary of the main results presented in two recent research reports [15, 16], from...... specimens in high-strength steel than those obtained in corresponding tests on joints in conventional offshore structural steel....

  2. Development of low-temperature high-strength integral steel castings for offshore construction by casting process engineering

    Science.gov (United States)

    Lim, Sang-Sub; Mun, Jae-Chul; Kim, Tae-Won; Kang, Chung-Gil

    2014-12-01

    In casting steels for offshore construction, manufacturing integral casted structures to prevent fatigue cracks in the stress raisers is superior to using welded structures. Here, mold design and casting analysis were conducted for integral casting steel. The laminar flow of molten metal was analyzed and distributions of hot spots and porosities were studied. A prototype was subsequently produced, and air vents were designed to improve the surface defects caused by the release of gas. A radiographic test revealed no internal defects inside the casted steel. Evaluating the chemical and mechanical properties of specimens sampled from the product revealed that target values were quantitatively satisfied. To assess weldability in consideration of repair welding, the product was machined with grooves and welded, after which the mechanical properties of hardness as well as tensile, impact, and bending strengths were evaluated. No substantive differences were found in the mechanical properties before and after welding.

  3. An Investigation on Fatigue in High-Strength Steel Offshore Structures

    DEFF Research Database (Denmark)

    Agerskov, Henning; Petersen, R.I.; Lopez Martinez, L.

    1997-01-01

    In the present investigation, the fatigue life of offshore steel structures in high-strength steel is studied. The material used has a yield stress of 800-1000 MPa, and high weldability and toughness properties. Of special interest is the fatigue life under a realistic stochastic loading....... In the experimental part of the investigation, fatigue test series have been carried through on both full-scale tubular joints and smaller welded plate test specimens, in high-strength steel as well as in conventional offshore structural steel. The present document gives a summary of the main results presented in two......, in general longer fatigue lives were obtained for the test specimens in high-strength steel than those obtained in corresponding tests on joints in conventional offshore structural steel....

  4. Fatigue Life of High-Strength Steel Offshore Tubular Joints

    DEFF Research Database (Denmark)

    Petersen, Rasmus Ingomar; Agerskov, Henning; Lopez Martinez, Luis

    1996-01-01

    In the present investigation, the fatigue life of tubular joints in offshore steel structures is studied. Two test series on full-scale tubular joints have been carried through. One series was on joints in conventional offshore structural steel, and the other series was on joints in high-strength...... steel with a yield stress of 820-830 MPa and with high weldability and toughness properties. The test specimens of both series had the same geometry. The present report concentrates on the results obtained in the investigation on the high-strength steel tubular joints.The test specimens were fabricated...... amplitude fatigue test results showed shorter fatigue lives in variable amplitude loading than should be expected from the linear fatigue damage accumulation formula. Furthermore, the fatigue tests on high-strength steel tubular joints showed slightly longer fatigue lives than those obtained...

  5. Use of a gray level co-occurrence matrix to characterize duplex stainless steel phases microstructure

    Directory of Open Access Journals (Sweden)

    L. Zortea

    2011-04-01

    Full Text Available Duplex stainless steels are widely used in industry. This is due to their higher strength compared to austenitic steels and to their higher toughness than ferritic steels. They also have good weldability and high resistance to stress corrosion cracking.These steels are characterized by two-phase microstructures composed by almost the same level of ferrite and austenite.Duplex steel 2205 samples evaluated are: as received, cold rolled (33% and heat-treated at 800°C for 10 hours.A metallographic etching with 10% oxalic acid has been carried out to highlight the phases morphology. Some photos have been taken by SEM microscope and submitted to image analysis. The analysis carried out is based on the determination of co-occurrence matrix and on the following interpretation of appropriate indicators. Through these indicators is possible to estimate the features of images objectively.

  6. An Alternate to Cobalt-Base Hardfacing Alloys

    Science.gov (United States)

    Hickl, Anthony J.

    1980-03-01

    The price of cobalt has risen dramatically in the last few years, and supply has often been uncertain. The most popular hardfacing alloys contain substantial amounts of cobalt, and have thus been especially affected by these factors. The present study has developed a new hardfacing alloy, HAYNES Alloy No. 716, with lower cobalt content, to replace the most popular alloy, HAYNES STELLITE Alloy No. 6 which is cobalt based. The alloy design which led to the development of the new alloy is discussed, and properties are compared with Alloy No. 6. Hardness at room temperature and elevated temperatures, weldability, and corrosion and abrasion resistance of the new alloy compare favorably with Alloy No. 6.

  7. Weld overlay cladding with iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, G.M. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    The hot and cold cracking tendencies of some early iron aluminide alloy compositions have limited their use in applications where good weldability is required. Using hot crack testing techniques invented at ORNL, and experimental determinations of preheat and postweld heat treatment needed to avoid cold cracking, we have developed iron aluminide filler metal compositions which can be successfully used to weld overlay clad various substrate materials, including 9Cr-1Mo steel, 2-1/4Cr-1Mo steel, and 300-series austenitic stainless steels. Dilution must be carefully controlled to avoid crack-sensitive deposit compositions. The technique used to produce the current filler metal compositions is aspiration-casting, i.e. drawing the liquid from the melt into glass rods. Future development efforts will involve fabrication of composite wires of similar compositions to permit mechanized gas tungsten arc (GTA) and/or gas metal arc (GMA) welding.

  8. Bringing Pulsed Laser Welding into Production

    DEFF Research Database (Denmark)

    Olsen, Flemmming Ove

    1996-01-01

    -nationally the group is mostly known for its contri-butions to the development of the laser cutting process, but further it has been active within laser welding, both in assisting industry in bringing laser welding into production in several cases and in performing fundamental R & D. In this paper some research...... activities concerning the weldability of high alloyed austenitic stainless steels for mass production industry applying industrial lasers for fine welding will be described. Studies on hot cracking sensitivity of high alloyed austenitic stainless steel applying both ND-YAG-lasers and CO2-lasers has been...... performed and is currently in progress in collaboration with a major Danish company, who currently is applying laser welding in several production lines. Furthermore some case stories from development work on laser welding for industri-al production will be described. One case story describes a current...

  9. Commercialization status of Ni{sub 3}Al-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-12-31

    The Ni{sub 3}Al-based alloys have been under development at the Oak Ridge National Laboratory (ORNL) and other research institutions in the United States and around the world for the last ten years. The incremental developments of composition, melting process, casting methods, property data, corrosion data, weldability development, and prototype component testing under production-like operating conditions have pushed the ORNL-developed Ni{sub 3}Al-based alloys closer to commercialization. This paper will present the highlights of incremental technical developments along with the approach and current status of commercialization. It is concluded that cast components are the primary applications of Ni{sub 3}Al-based alloys, and applications range from heat-treating fixtures of forging dies. It is also concluded that the commercialization process is accelerated when technology is licensed to an organization that can produce the alloy, has component manufacturing capability, and is also a user.

  10. The effect of carbon content on the structure-property of HSLA-100 steels

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, C.I.; Mujahid, M.; DeArdo, A.J. [Univ. of Pittsburgh, PA (United States). Basic Metals Processing Research Inst.

    1995-12-31

    A major attraction of modern structural steels is their ability to offer a reduction in fabrication costs without compromising the quality and performance of the structure. For example, the relatively new family of high strength low alloy (HSLA-100) steels with copper additions features a reduction in the carbon content which leads to subsequent improvements in toughness and weldability. The strength in these steels is derived from a highly dislocated aged martensite and the precipitation of Cu particles which retards the softening associated during the aging process. Formation of austenite is also observed during aging around 640 C which is indicative of the low Ac{sub 1} temperature for this kind of steel composition. The purpose of this paper was to study the effect of carbon content on the structure-property relation of HSLA-100 steels.

  11. Multiple welding of long fiber epoxy vitrimer composites.

    Science.gov (United States)

    Chabert, Erwan; Vial, Jérôme; Cauchois, Jean-Pierre; Mihaluta, Marius; Tournilhac, François

    2016-05-25

    Vitrimers appear as a new class of polymers that exhibit mechanical strength and are insoluble even at high temperatures, like thermosets, and yet, like thermoplastics, they are heat processable, recyclable and weldable. The question arises whether this welding property is maintained in composite materials made of more than 50 vol% of reinforcing fibers. In this paper, we quantitatively analyze the bond strength of epoxy vitrimer-based composite plates made by resin transfer molding and compare them to their non-vitrimer counterparts made of a standard thermoset epoxy. It is demonstrated that only epoxy vitrimer samples show substantial bond strength and the ability to be repeatedly welded thanks to the exchange reactions, which promote improved surface conformity and chemical bonding between the adherands at the joint interface. This opens the way towards joining composite parts without adhesives nor mechanical fasteners.

  12. An experimental study of high-hydrogen welding processes

    Energy Technology Data Exchange (ETDEWEB)

    Fydrych, D.; Labonowski, J.

    2015-07-01

    This paper presents investigation results of determination of the diffusible hydrogen content in deposited metal obtained by means of two most often used methods-the glycerin method and the mercury method. Relation has been defined between results of those methods in the area characteristic of low-hydrogen as well as high-hydrogen welding processes. Relations available in the literature do not include the diffusible hydrogen content in deposited metal greater than 35 ml/100 g. Extending the scope of analysis of the diffusible hydrogen quantity to an 80 ml/100 g level considerably simplifies carrying out the steel weldability assessment with the use of high-hydrogen processes and with welding in water environment. (Author)

  13. Laser cladding of titanium alloy coating on titanium aluminide alloy substrate

    Institute of Scientific and Technical Information of China (English)

    徐子文; 黄正; 阮中健

    2003-01-01

    A new diffusion bonding technique combined with laser cladding process was developed to join TiAl alloy to itself and Ti-alloys. In order to enhance the weldability of TiAl alloys, Ti-alloy coatings were fabricated by laser cladding on the TiAl alloy. Ti powder and shaped Ti-alloy were respectively used as laser cladding materials. The materials characterization was carried out by OM, SEM, EDS and XRD analysis. The results show that the laser cladding process with shaped Ti-alloy remedy the problems present in the conventional process with powder, such as impurities, cracks and pores. The diffusion bonding of TiAl alloy with Ti-alloy coating to itself and Ti-alloy was carried out with a Gleeble 1500 thermal simulator. The sound bonds of TiAl/TiAl, TiAl/Ti were obtained at a lower temperature and with shorter time.

  14. Friction Stir Welding of ODS and RAFM Steels

    Science.gov (United States)

    Yu, Zhenzhen; Feng, Zhili; Hoelzer, David; Tan, Lizhen; Sokolov, Mikhail A.

    2015-09-01

    Advanced structural materials such as oxide dispersion strengthened steels and reduced-activation ferritic/martensitic steels are desired in fusion reactors as primary candidate materials for first wall and blanket structures, due to their excellent radiation and high-temperature creep resistance. However, their poor fusion weldability has been the major technical challenge limiting practical applications. For this reason, solid-state friction stir welding (FSW) has been considered for such applications. In this work, the effect of FSW parameters on joining similar and dissimilar advanced structural steels was investigated. Scanning electron microscopy and electron backscatter diffraction methods were used to reveal the effects of FSW on grain size, micro-texture distribution, and phase stability. Hardness mapping was performed to evaluate mechanical properties. Post weld heat treatment was also performed to tailor the microstructure in the welds in order to match the weld zone mechanical properties to the base material.

  15. Technical challenges of heavy wall HFW pipe production for Bord Gais Eireann pipeline project

    Energy Technology Data Exchange (ETDEWEB)

    O' Dwyer, Paul [Transmission Design Manager, Cork, (Ireland); Boothbym, Peter [MACAW Engineering Ltd., Newcastle, (United Kingdom); Tazedakis, Athanasios [Corinth Pipeworks S.A, Viotia, (Greece)

    2010-07-01

    This paper deals with the pipeline recently constructed by Bord Gais Eireann near the city of Cork in The Irish Republic. The 47.5 km pipeline comprises over 30 km of 9.5 mm and 17 km of 19.1 mm wall thickness for an outside diameter of 610 mm. This paper presents the global engineering approach adopted for the project and describes more in detail the specificities of the project and the challenges faced during production. One of the difficulties encountered was to manufacture a high strength pipeline of 19.1 mm wall thickness for HFW produced pipeline. The chemical composition of the 19.1 mm coil strip had also required new developments to accommodate the demanding drop weight tear test toughness requirement. Several methods were applied to mitigate potential risks such as increase of initial production test frequency, close monitoring during pipe production, identification of potential construction issues and the weldability performance were also tested.

  16. Segregation of B, P, and C in the Ni-Based Superalloy, Inconel 718

    Science.gov (United States)

    Alam, Talukder; Felfer, Peter J.; Chaturvedi, Mahesh; Stephenson, Leigh T.; Kilburn, Matthew R.; Cairney, Julie M.

    2012-07-01

    Small additions of B, P, and C can result in dramatic changes in the mechanical performance and welding behavior of Inconel 718. Although additions of B and P improve the mechanical properties, they have a detrimental effect on weldability. Adding C mitigates the negative effect on welding while retaining the improvements in mechanical performance. In this study, precise observations of the segregation of B, P, and C to the grain boundaries are made using site-specific atom probe tomography and NanoSIMS. Changes in the segregation behavior provide a quantitative explanation for the welding response, where hot cracking is attributed to the formation of a eutectic film. Calculations of the relative positions of the B, P, and C revealed that these atoms were less likely to cluster together in the presence of C, providing insight into the likely mechanisms behind the segregation behavior in this complex, multicomponent alloy.

  17. Welding technology for rails. Rail no setsugo gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, M.; Karimine, K. (Nippon Steel Corp., Tokyo (Japan)); Uchino, K.; Sugino, K. (Nippon Steel Corp., Kitakyushu, Fukuoka (Japan). Technical Research Inst. of Yawata Works); Ueyama, K. (JR Railway Technical Research Inst., Tokyo (Japan))

    1993-08-01

    The rail joining technology is indispensable for making long welded rails. Flush butt welding, gas welding, enclosed arc welding, and thermit welding are used properly as the welding methods. A method for improving the joint reliability by controlling the residual stress distribution of welded joint is investigated to prepare high carbon component weld metal similar to the rail. Problems with each of the welding methods and the newly developed technology to solve the problems are outlined. Composition of the coating is improved also, and a high C system welding rod is developed which has satisfactory weldability. High performance and high efficient new enclosed arc welding technology not available by now is developed which utilizes high carbon welding metal as a new EA welding work technology, and put to practical use. As a result of this study, useful guides are obtained for the establishment of satisfactory thermit welding technology. 17 refs., 16 figs., 1 tab.

  18. Review on δ-Transformation-Induced Plasticity (TRIP) Steels with Low Density: The Concept and Current Progress

    Science.gov (United States)

    Yi, H. L.

    2014-09-01

    Novel alloys with high aluminum addition, so-called δ-transformation-induced plasticity (TRIP), have been developed recently for the third generation of advanced high strength steels for automotive applications, which are promising owing to the potential weldability as well as the combination of strength and ductility. In addition, the high aluminum addition results in a density reduction of approximately 5% in these δ-TRIP alloys without sacrificing the Young's modulus in uniaxial tensile tests. The origin of δ-TRIP concept is introduced first with a review of the published work on δ-TRIP alloys. This review will include methodology for retention of δ-ferrite in casting, rolling and welding conditions, microstructure evolution by austempering, as well as microstructures-properties relationship involving the roles of blocky and lath retained austenite. In addition, currently unresolved problems will be discussed regarding the fundamentals of materials design, automotive application, and industrial manufacturing.

  19. Low-mass, intrinsically-hard high temperature radiator. Final report, Phase I

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1990-07-15

    This paper reports on the investigation of layered ceramic/metal composites in the design of low-mass hardened radiators for space heat rejection systems. The investigation is part of the Strategic Defence Initiative. This effort evaluated the use of layered composites as a material to form thin-walled, vacuum leaktight heat pipes. The heat pipes would be incorporated into a large heat pipe radiator for waste heat rejection from a space nuclear power source. Composite materials evaluations were performed on combinations of refractory metals and ceramic powders. Fabrication experiments were performed to demonstrate weldability. Two titanium/titanium diboride composite tubes were successfully fabricated into potassium heat pipes and operated at temperatures in excess of 700C. Testing and analysis for composite tubes are described in the report. The study has verified the feasibility of using layered composites for forming thin-walled, light weight heat pipe tubes for use in hardened space radiators.

  20. Resistance welding of carbon fibre reinforced polyetheretherketone composites using metal mesh and PEI film

    Institute of Scientific and Technical Information of China (English)

    闫久春; 王晓林; 秦明; 赵新英; 杨士勤

    2004-01-01

    Weldability of polyetheretherketone(PEEK) with polyetherimide(PEI) is tested. And carbon fiber reinforced PEEK laminates are resistance welded using stainless steel mesh heating element. The effects of the welding time and welding pressure on the lap shear strength of joints are investigated. Results show that PEEK can heal with PEI well in welding condition and the lap shear strength of PEEK/CF(carbon fibre) joint increases linearly with welding time, but reaches a maximum value when welding pressure ranging from 0.3MPa to 0.5MPa with constant welding time. The fracture characteristics of surface are analyzed by SEM techniques, and four types of fracture modes of lap shear joints are suggested.

  1. Modelling of damage development and ductile failure in welded joints

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    This thesis focuses on numerical analysis of damage development and ductile failure in welded joints. Two types of welds are investigated here. First, a study of the localization of plastic flow and failure in aluminum sheets, welded by the relatively new Friction Stir (FS) Welding method, has been...... conducted ([P1], [P2], [P7]-[P9]). The focus in the thesis is on FS-welded 2xxx and 6xxx series of aluminum alloys, which are attractive, for example, to the aerospace industry, since the 2024 aluminum in particular, is typically classified as un-weldable by conventional fusion welding techniques. Secondly......, a study of the damage development in Resistance SpotWelded joints, when subject to the commonly used static shear-lab or cross-tension testing techniques, has been carried out ([P3]-[P6]). The focus in thesis is on the Advanced High Strength Steels, Dual-Phase 600, which is used in for example...

  2. Effects of mechanical force on grain structures of friction stir welded oxide dispersion strengthened ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Han, Wentuo, E-mail: hanwentuo@hotmail.com [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kimura, Akihiko [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Tsuda, Naoto [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Serizawa, Hisashi [Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Chen, Dongsheng [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Je, Hwanil [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Fujii, Hidetoshi [Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Ha, Yoosung [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Morisada, Yoshiaki [Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Noto, Hiroyuki [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

    2014-12-15

    The weldability of oxide dispersion strengthened (ODS) ferritic steels is a critical obstructive in the development and use of these steels. Friction stir welding has been considered to be a promising way to solve this problem. The main purpose of this work was to reveal the effects of mechanical force on grain structures of friction stir welded ODS ferritic steel. The grain appearances and the misorientation angles of grain boundaries in different welded zones were investigated by the electron backscatter diffraction (EBSD). Results showed that the mechanical force imposed by the stir tool can activate and promote the recrystallization characterized by the transformation of boundaries from LABs to HABs, and contribute to the grain refinement. The type of recrystallization in the stir zone can be classified as the continuous dynamic recrystallization (CDRX)

  3. Effects of Thermocapillary Forces during Welding of 316L-Type Wrought, Cast and Powder Metallurgy Austenitic Stainless Steels

    CERN Document Server

    Sgobba, Stefano

    2003-01-01

    The Large Hadron Collider (LHC) is now under construction at the European Organization for Nuclear Research (CERN). This 27 km long accelerator requires 1248 superconducting dipole magnets operating at 1.9 K. The cold mass of the dipole magnets is closed by a shrinking cylinder with two longitudinal welds and two end covers at both extremities of the cylinder. The end covers, for which fabrication by welding, casting or Powder Metallurgy (PM) was considered, are dished-heads equipped with a number of protruding nozzles for the passage of the different cryogenic lines. Structural materials and welds must retain high strength and toughness at cryogenic temperature. AISI 316L-type austenitic stainless steel grades have been selected because of their mechanical properties, ductility, weldability and stability of the austenitic phase against low-temperature spontaneous martensitic transformation. 316LN is chosen for the fabrication of the end covers, while the interconnection components to be welded on the protrud...

  4. An application of powder metallurgy for the LHC

    CERN Document Server

    Sgobba, Stefano

    2004-01-01

    The cold mass of the 1232 superconducting dipole magnets of LHC, operating at 1.9 K, is enclosed by a shrinking cylinder and two end covers at its extremities. The covers are structural components that must retain high strength and toughness at cryogenic temperature. They are manufactured by Metso Oy /FI in AISI 316 LN steel by Powder Metallurgy (PM) and Hot Isostatic Pressing. PM represents an attractive near net shaping technique for these components of complex geometry for which dimension tolerances, dimensional stability, weldability are key issues for magnet fabrication, and mechanical properties, ductility and leak tightness have to be guaranteed during operation. The material of the covers and its welds have been fully characterized and mechanically tested down to 4.2 K at CERN. The fine grained structure, the absence of residual stresses, the full isotropy of mechanical properties associated to the low level of Prior Particle Boundaries oxides result in superior mechanical properties and high ductilit...

  5. Effect of Al2O3 on Structure and Wearability of Composite Coating

    Institute of Scientific and Technical Information of China (English)

    DING Hong-yan; ZHANG Yue

    2004-01-01

    The composite coating was prepared by thermal spray welding after making composite powder, which is composed of Ni-based self-melted alloy and Al2O3 ceramic powder including nano, sub-micron and micron powders. The influences of contents and sizes of Al2O3 on the structure and wearability were investigated. The results show that the wear resistance of the coating would be increased greatly by adding Al2O3, but the spray weldability decreases with increasing Al2O3 content. So there is an optimal content of Al2O3 powder. The composite coating with Al2O3 nano or sub-micron powder of 0.5 % has the best abrasive resistance, while the optimal content of Al2O3 micron powder is 1%.

  6. Low cost fabrication of sheet structure using a new beta titanium alloy, Ti-15V-3Cr-3Al-3Sn

    Science.gov (United States)

    Kaneko, R. S.; Davis, G. W.; Woods, C. A.; Royster, D. M.

    1982-01-01

    Development efforts have been undertaken to improve the processing and structural efficiencies of advanced cold-formable beta Ti alloys, using the standard, hot-formed and rivetted construction of Ti-6Al-4V sheet structures as a basis for comparison. Ti-15V-3Cr-3Al-3Sn (Ti-15-3) beta alloy is formable, brazable and weldable in the solution-treated condition, and after aging displays mechanical properties suitable for postulated service in the -65 to 600 F temperature range. A novel methodology using cold-formed Ti-15-3 stringers and Ti-6Al-4V face sheets that are joined by means of an out-of-furnace isothermal brazing process, followed by low temperature aging, can reduce production costs by as much as 28 per cent. Structural efficiency has been demonstrated in room and elevated temperature crippling tests of small skin-stringer assemblies.

  7. Low cost fabrication of sheet structure using a new beta titanium alloy, Ti-15V-3Cr-3Al-3Sn

    Science.gov (United States)

    Kaneko, R. S.; Davis, G. W.; Woods, C. A.; Royster, D. M.

    1982-01-01

    Development efforts have been undertaken to improve the processing and structural efficiencies of advanced cold-formable beta Ti alloys, using the standard, hot-formed and rivetted construction of Ti-6Al-4V sheet structures as a basis for comparison. Ti-15V-3Cr-3Al-3Sn (Ti-15-3) beta alloy is formable, brazable and weldable in the solution-treated condition, and after aging displays mechanical properties suitable for postulated service in the -65 to 600 F temperature range. A novel methodology using cold-formed Ti-15-3 stringers and Ti-6Al-4V face sheets that are joined by means of an out-of-furnace isothermal brazing process, followed by low temperature aging, can reduce production costs by as much as 28 per cent. Structural efficiency has been demonstrated in room and elevated temperature crippling tests of small skin-stringer assemblies.

  8. Materials for high vacuum technology, an overview

    CERN Document Server

    Sgobba, Stefano

    2007-01-01

    In modern accelerators stringent requirements are placed on materials of vacuum systems. Their physical and mechanical properties, machinability, weldability or brazeability are key parameters. Adequate strength, ductility, magnetic properties at room as well as low temperatures are important factors for vacuum systems of accelerators working at cryogenic temperatures, such as the Large Hadron Collider (LHC) under construction at CERN. In addition, baking or activation of Non-Evaporable Getters (NEG) at high temperatures impose specific choices of material grades of suitable tensile and creep properties in a large temperature range. Today, stainless steels are the dominant materials of vacuum constructions. Their metallurgy is extensively treated. The reasons for specific requirements in terms of metallurgical processes are detailed, in view of obtaining adequate purity, inclusion cleanliness, and fineness of the microstructure. In many cases these requirements are crucial to guarantee the final leak tightnes...

  9. Photoemission Electron Microscopy as a Tool for Studying Steel Grains

    Science.gov (United States)

    Roese, Peter; Keutner, Christoph; Berges, Ulf; Espeter, Philipp; Westphal, Carsten

    2017-01-01

    Key properties of steel like stability, weldability, or ability for absorbing deformation energy are defined by their grain structure. The knowledge about their micrometer and submicrometer structure is of particular interest for tailor-cut macroscopic steel properties. We report on photoemission electron microscopy studies which in principle yield a higher magnification than comparable optical techniques. A flat surface without any topographic features was obtained by applying a non-etching preparation procedure. PEEM images showed very tiny phase islands embedded within a steel phase matrix. Furthermore, we developed an analysis procedure for PEEM images for dual-phase steels. As a result, it is possible to identify the individual work functions of different steel phases at the surface.

  10. Microstructure and calorimetric behavior of laser welded open cell foams in CuZnAl shape memory alloy

    Science.gov (United States)

    Biffi, Carlo Alberto; Previtali, Barbara; Tuissi, Ausonio

    Cellular shape memory alloys (SMAs) are very promising smart materials able to combine functional properties of the material with lightness, stiffness, and damping capacity of the cellular structure. Their processing with low modification of the material properties remains an open question. In this work, the laser weldability of CuZnAl SMA in the form of open cell foams was studied. The cellular structure was proved to be successfully welded in lap joint configuration by using a thin plate of the same alloy. Softening was seen in the welded bead in all the investigated ranges of process speed as well as a double stage heat affected zone was identified due to different microstructures; the martensitic transformation was shifted to higher temperatures and the corresponding peaks were sharper with respect to the base material due to the rapid solidification of the material. Anyways, no compositional variations were detected in the joints.

  11. Development of advanced high strength tantalum base alloys. Part 2: Scale-up investigation

    Science.gov (United States)

    Ammon, R. L.; Buckman, R. W., Jr.

    1970-01-01

    Three experimental tantalum alloy compositions containing 14-16% W, 1% Re, 0.7% Hf, 0.025% C or 0.015% C and 0.015% N were prepared as two inch diameter ingots by consumable electrode vacuum arc melting. The as-cast ingots were processed by extrusion and swaging to one inch and 0.4 inch diameter rod and evaluated. Excellent high temperature forging behavior was exhibited by all three compositions. Creep strength at 2000 F to 2400 F was enhanced by higher tungsten additions as well as substitution of nitrogen for carbon. Weldability of all three compositions was determined to be adequate. Room temperature ductility was retained in the advanced tantalum alloy compositions as well as a notched/unnotched strength ratio of 1.4 for a notched bar having a K sub t = 2.9.

  12. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2011-01-01

    Offers an introduction to the range of available welding technologies. This title includes chapters on individual techniques that cover principles, equipment, consumables and key quality issues. It includes material on such topics as the basics of electricity in welding, arc physics, and distortion, and the weldability of particular metals.$bThe first edition of Welding processes handbook established itself as a standard introduction and guide to the main welding technologies and their applications. This new edition has been substantially revised and extended to reflect the latest developments. After an initial introduction, the book first reviews gas welding before discussing the fundamentals of arc welding, including arc physics and power sources. It then discusses the range of arc welding techniques including TIG, plasma, MIG/MAG, MMA and submerged arc welding. Further chapters cover a range of other important welding technologies such as resistance and laser welding, as well as the use of welding techniqu...

  13. Status Report on Irradiation Capsules Containing Welded FeCrAl Specimens for Radiation Tolerance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-02-26

    This status report provides the background and current status of a series of irradiation capsules, or “rabbits”, that were designed and built to test the contributions of microstructure, composition, damage dose, and irradiation temperature on the radiation tolerance of candidate FeCrAl alloys being developed to have enhanced weldability and radiation tolerance. These rabbits will also test the validity of using an ultra-miniature tensile specimen to assess the mechanical properties of irradiated FeCrAl base metal and weldments. All rabbits are to be irradiated in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) to damage doses up to ≥15 dpa at temperatures between 200-550°C.

  14. Fatigue and fracture properties of a super-austenitic stainless steel at 295 K and 4 K

    Science.gov (United States)

    McRae, D. M.; Walsh, R. P.; Dalder, E. N. C.; Litherland, S.; Trosen, M.; Kuhlmann, D. J.

    2014-01-01

    The tie plate structure for the ITER Central Solenoid (CS) is required to have high strength and good fatigue and fracture behavior at both room temperature and 4 K. A super-austenitic stainless steel - UNS 20910, commonly referred to by its trade name, Nitronic 50 (N50) - has been chosen for consideration to fulfill this task, due to its good room temperature and cryogenic yield strengths and weldability. Although N50 is often considered for cryogenic applications, little published data exists at 4 K. Here, a full series of tests have been conducted at 295 K and 4 K, and static tensile properties of four forgings of commercially-available N50 are reported along with fatigue life, fatigue crack growth rate (FCGR), and fracture toughness data. This study makes a significant contribution to the cryogenic mechanical properties database of high strength, paramagnetic alloys with potential for superconducting magnet applications.

  15. Evolution of microstructure and mechanical properties during Q&P processing of medium-carbon steels with different silicon levels

    Science.gov (United States)

    Jenicek, S.; Vorel, I.; Kana, J.; Opatova, K.; Rubesova, K.; Kotesovec, V.; Masek, B.

    2017-03-01

    Evolution of microstructure during heat treatment plays a fundamental role in the resulting mechanical properties of steel. Today, mechanical properties in conjunction with technological properties, such as weldability, formability, and machinability, and their optimum combinations, are widely discussed in a number of mechanical engineering disciplines. In this manner, requirements arise for developing steels which could offer high strength and good formability, and which could be used for making parts with high resistance to failure and with a long life. One present-day example of such steels involves Q&P-processed martensitic steels. Their properties are dictated by their treatment, as well as their alloying, particularly by the silicon content. Silicon fundamentally affects microstructure evolution during Q&P processing and, as a result, mechanical properties. With this way it is possible to receive microstructures consinsting of martensite and retained austenite with an ultimate tensile stress of more than 1600 MPa and a uniform elongation of more than 12 %.

  16. Review on Improving Wear and Corrosion Resistance of Steels via Plasma Electrolytic Saturation Technology

    Science.gov (United States)

    Lin, Naiming; Xie, Ruizhen; Zhou, Peng; Zou, Jiaojuan; Ma, Yong; Wang, Zhenxia; Han, Pengju; Wang, Zhihua; Tang, Bin; Tian, Wei

    2016-03-01

    Plasma electrolytic saturation (PES) technique which holds the advantages of short treating time and limited heating influence and immediate quenching effect is conducted under high voltage power supply in some electrolyte has been extensively applied to enhance the surface performance of metallic materials. Steel is widely used in various fields thanks to its promising merits of easy workability, plasticity, toughness and weldability. It accounts for a large proportion in the application scope of the metal materials. Steel surfaces with good corrosion resistance, promising wear resistance and high hardness would be obtained by PES. Meanwhile, uniformed coatings can be formed without special requirements for substrate geometries using the PES. This paper first presents a brief introduction of the technological principle of PES. The status on studies and applications of PES for improving surface performance of steels has been reviewed.

  17. Analysis of Acoustic Emission Signals During Laser Spot Welding of SS304 Stainless Steel

    Science.gov (United States)

    Lee, Seounghwan; Ahn, Suneung; Park, Changsoon

    2014-03-01

    In this article, an in-process monitoring scheme for a pulsed Nd:YAG laser spot welding (LSW) is presented. Acoustic emission (AE) was selected for the feedback signal, and the AE data during LSW were sampled and analyzed for varying process conditions such as laser power and pulse duration. In the analysis, possible AE generation sources such as melting and solidification mechanism during welding were investigated using both the time- and frequency-domain signal processings. The results, which show close relationships between LSW and AE signals, were adopted in the feature (input) selection of a back-propagation artificial neural network, to predict the weldability of stainless steel sheets. Processed outputs agree well with LSW experimental data, which confirms the usefulness of the proposed scheme.

  18. Experimental Determination of the Primary Solidification Phase dependency on the solidification velocity for 17 different austenitic stainless steel compositions

    DEFF Research Database (Denmark)

    Laursen, Birthe Nørgaard; Olsen, Flemming Ove; Yardy, John

    1997-01-01

    When studying laser welding of austenitic stainless steel, hot cracking is frequently observed. To prevent hot cracking in laser welded stainless steel it is advantageous to obtain primary solidification of the ferrite phase that subsequently, on cooling, transforms in the solid state...... to the austenite phase.Most stainless steels are weldable by conventional welding techniques. However, during laser weldng the solidification velocities can be very much higher than by conventional welding techniques. By increasing the solidification velocity to a critical value known as the transition velocity......, the primary solidification phase is found to change from ferrite to austenite.A novel laser remelting technique has been modified to enable the transition velocity for laser welded austenitic stainless steels to be deermined experimentally and on the basis of results from 17 different alloy compositions...

  19. Technical issues of reduced activation ferritic/martensitic steels for fabrication of ITER test blanket modules

    Energy Technology Data Exchange (ETDEWEB)

    Tanigawa, H. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)], E-mail: tanigawa.hiroyasu@jaea.go.jp; Hirose, T.; Shiba, K. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Kasada, R. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Wakai, E. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Serizawa, H.; Kawahito, Y. [Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Jitsukawa, S. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Kimura, A. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kohno, Y. [Department of Materials Science and Engineering, Muroran Institute of Technology, Muroran, Hokkaido 050-8585 (Japan); Kohyama, A. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Katayama, S. [Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Mori, H.; Nishimoto, K. [Division of Materials and Manufacturing Science, Osaka University, Ibaraki, Osaka 565-0871 (Japan); Klueh, R.L.; Sokolov, M.A.; Stoller, R.E.; Zinkle, S.J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6132 (United States)

    2008-12-15

    Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems. The RAFM F82H was developed in Japan with emphasis on high-temperature properties and weldability. Extensive irradiation studies have conducted on F82H, and it has the most extensive available database of irradiated and unirradiated properties of all RAFMs. The objective of this paper is to review the R and D status of F82H and to identify the key technical issues for the fabrication of an ITER test blanket module (TBM) suggested from the recent research achievements in Japan. This work clarified that the primary issues with F82H involve welding techniques and the mechanical properties of weld joints. This is the result of the distinctive nature of the joint caused by the phase transformation that occurs in the weld joint during cooling, and its impact on the design of a TBM will be discussed.

  20. Etude expérimentale du soudage par laser YAG de l'alliage base nickel Hastelloy X Experimental study of YAG laser welding of nickel base alloy Hastelloy X

    Directory of Open Access Journals (Sweden)

    Graneix Jérémie

    2013-11-01

    Full Text Available Le procédé de soudage laser YAG est envisagé pour remplacer le procédé de soudage TIG manuel pour la réalisation de pièces de turboréacteur en alliage nickel-chrome-molybdène Hastelloy X. Cette étude expérimentale a permis de définir un domaine de soudabilité de cet alliage répondant aux critères spécifiques du secteur aéronautique. The YAG laser welding process is contemplated to replace the manual TIG welding process for the production of parts of turbojet in Hastelloy X. This experimental study has identified the field of weldability of this alloy to meet the specific requirements of the aerospace industry.

  1. Development of Aluminium Vacuum Chambers for the LHC Experiments at CERN

    CERN Document Server

    Gallilee, M; Costa-Pinto, P; Lepeule, P; Perez-Espinos, J; Marques Antunes Ferreira, L; Prever-Loiri, L; Sapountzis, A

    2014-01-01

    Beam losses may cause activation of vacuum chamber walls, in particular those of the Large Hadron Collider (LHC) experiments. For the High Luminosity (HL-LHC), the activation of such vacuum chambers will increase. It is therefore necessary to use a vacuum chamber material which interacts less with the circulating beam. While beryllium is reserved for the collision point, a good compromise between cost, availability and transparency is obtained with aluminium alloys; such materials are a preferred choice with respect to austenitic stainless steel. Manufacturing a thin-wall aluminium vacuum chamber presents several challenges as the material grade needs to be machinable, weldable, leak-tight for small thicknesses, and able to withstand heating to 250°C for extended periods of time. This paper presents some of the technical challenges during the manufacture of these vacuum chambers and the methods for overcoming production difficulties, including surface treatments and Non-Evaporable Getter (NEG) thin-film coat...

  2. Comparison between hybrid laser-MIG welding and MIG welding for the invar36 alloy

    Science.gov (United States)

    Zhan, Xiaohong; Li, Yubo; Ou, Wenmin; Yu, Fengyi; Chen, Jie; Wei, Yanhong

    2016-11-01

    The invar36 alloy is suitable to produce mold of composite materials structure because it has similar thermal expansion coefficient with composite materials. In the present paper, the MIG welding and laser-MIG hybrid welding methods are compared to get the more appropriate method to overcome the poor weldability of invar36 alloy. According to the analysis of the experimental and simulated results, it has been proved that the Gauss and cone combined heat source model can characterize the laser-MIG hybrid welding heat source well. The total welding time of MIG welding is 8 times that of hybrid laser-MIG welding. The welding material consumption of MIG welding is about 4 times that of hybrid laser-MIG welding. The stress and deformation simulation indicate that the peak value of deformation during MIG welding is 3 times larger than that of hybrid laser-MIG welding.

  3. Processing of Advanced Cast Alloys for A-USC Steam Turbine Applications

    Science.gov (United States)

    Jablonski, Paul D.; Hawk, Jeffery A.; Cowen, Christopher J.; Maziasz, Philip J.

    2012-02-01

    The high-temperature components within conventional supercritical coal-fired power plants are manufactured from ferritic/martensitic steels. To reduce greenhouse-gas emissions, the efficiency of pulverized coal steam power plants must be increased to as high a temperature and pressure as feasible. The proposed steam temperature in the DOE/NETL Advanced Ultra Supercritical power plant is high enough (760°C) that ferritic/martensitic steels will not work for the majority of high-temperature components in the turbine or for pipes and tubes in the boiler due to temperature limitations of this class of materials. Thus, Ni-based superalloys are being considered for many of these components. Off-the-shelf forged nickel alloys have shown good promise at these temperatures, but further improvements can be made through experimentation within the nominal chemistry range as well as through thermomechanical processing and subsequent heat treatment. However, cast nickel-based superalloys, which possess high strength, creep resistance, and weldability, are typically not available, particularly those with good ductility and toughness that are weldable in thick sections. To address those issues related to thick casting for turbine casings, for example, cast analogs of selected wrought nickel-based superalloys such as alloy 263, Haynes 282, and Nimonic 105 have been produced. Alloy design criteria, melt processing experiences, and heat treatment are discussed with respect to the as-processed and heat-treated microstructures and selected mechanical properties. The discussion concludes with the prospects for full-scale development of a thick section casting for a steam turbine valve chest or rotor casing.

  4. Laser Engineered Net Shape (LENS) Technology for the Repair of Ni-Base Superalloy Turbine Components

    Science.gov (United States)

    Liu, Dejian; Lippold, John C.; Li, Jia; Rohklin, Stan R.; Vollbrecht, Justin; Grylls, Richard

    2014-09-01

    The capability of the laser engineered net shape (LENS) process was evaluated for the repair of casting defects and improperly machined holes in gas turbine engine components. Various repair geometries, including indentations, grooves, and through-holes, were used to simulate the actual repair of casting defects and holes in two materials: Alloy 718 and Waspaloy. The influence of LENS parameters, including laser energy density, laser scanning speed, and deposition pattern, on the repair of these defects and holes was studied. Laser surface remelting of the substrate prior to repair was used to remove machining defects and prevent heat-affected zone (HAZ) liquation cracking. Ultrasonic nondestructive evaluation techniques were used as a possible approach for detecting lack-of-fusion in repairs. Overall, Alloy 718 exhibited excellent repair weldability, with essentially no defects except for some minor porosity in repairs representative of deep through-holes and simulated large area casting defects. In contrast, cracking was initially observed during simulated repair of Waspaloy. Both solidification cracking and HAZ liquation cracking were observed in the repairs, especially under conditions of high heat input (high laser power and/or low scanning speed). For Waspaloy, the degree of cracking was significantly reduced and, in most cases, completely eliminated by the combination of low laser energy density and relatively high laser scanning speeds. It was found that through-hole repairs of Waspaloy made using a fine powder size exhibited excellent repair weldability and were crack-free relative to repairs using coarser powder. Simulated deep (7.4 mm) blind-hole repairs, representative of an actual Waspaloy combustor case, were successfully produced by the combination use of fine powder and relatively high laser scanning speeds.

  5. Soudage hybride Laser-MAG d'un acier Hardox® Hybrid Laser Arc Welding of a Hardox® steel

    Directory of Open Access Journals (Sweden)

    Chaussé Fabrice

    2013-11-01

    Full Text Available Le soudage hybride laser-MAG est un procédé fortement compétitif par rapport aux procédés conventionnels notamment pour le soudage de fortes épaisseurs et les grandes longueurs de soudure. Il connait de ce fait un développement important dans l'industrie. La présente étude s'est portée sur la soudabilité de l'acier Hardox® par ce procédé. Un large panel de techniques de caractérisation a été employé (mesures thermiques, radiographie X, duretés Vickers, macrographie…. L'objectif étant de déterminer l'influence des paramètres du procédé sur la qualité de la soudure et d'étendre notre compréhension des phénomènes se déroulant lors de ce type de soudage. Hybrid Laser Arc Welding (HLAW technology is a highly competitive metal joining process especially when high productivity is needed and for the welding of thick plates. It is a really new technology but its implementation in industry accelerates thanks to recent improvements of high power laser equipment and development of integrated hybrid welding heads. This study focuses on weldability of Hardox® 450 steel by HLAW. Welding tests were conducted by making critical process parameters vary. Then a large panel of characterization techniques (X-Ray radiography, macroscopic examination and hardness mapping was used to determine process parameters influence on weldability of Hardox 450® Steel.

  6. Microstructural analysis of weld cracking in 718 Plus superalloy

    Science.gov (United States)

    Vishwakarma, Krutika

    Allvac 718RTM PLUS(TM) (718 Plus) is a new Ni-base superalloy developed to be used in land and aero gas turbine applications. 718 Plus was developed to have high temperature properties superior to its baseline superalloy Inconel 718, while maintaining its workability. Besides its high temperature properties superior to Inconel 718, limited information exists about its physical metallurgy or weldability. This project studied the microstructure and electron beam welding response of this new superalloy in two selected pre-weld heat treated conditions. To further understand the effect of minor alloying elements on its weldability, two versions of 718 Plus with varying concentrations of boron and phosphorus, HC 49 with higher B and P and HC 20 with normal B and P, were also studied. Finally, the weldability of 718 Plus alloys was compared to that of Inconel 718 and Waspaloy under similar welding conditions. Hot rolled wrought plates of Inconel 718, Waspaloy and 718 Plus alloys were supplied by ALLVAC Inc. 12.7 mm x 12.7 mm x 101.6 mm sections were cut normal to the rolling direction of the plates and were subjected to their recommended respective solution heat treatments, viz., 950°C for 1 hour for 718 Plus alloys and Inconel 718 and 1020°C for 1 hour for Waspaloy. 718 Plus alloys and Inconel 718 were also examined after another solution heat treatment at 1050°C for 1 hour. All the heat treatments were followed by water quenching. Thorough microstructural characterization before and after welding was carried out using optical microscopy, analytical scanning electron microscopy, electron microprobe analysis and analytical transmission electron microscopy. In addition, Secondary Ion Mass Spectrometer (SIMS) was used to study the grain boundary segregation in the two 718 Plus alloys. Interestingly, the microstructure of 718 Plus alloy, in the heat treated conditions it was studied, was very similar to that of Inconel 718 despite of the considerable difference in their

  7. Technical issues of RAFMs for the fabrication of ITER Test Blanket Module

    Energy Technology Data Exchange (ETDEWEB)

    Tanigawa, Hiroyasu; Hirose, Takanori; Shiba, Kiyoyuki [Japan Atomic Energy Agency (JP)] (and others)

    2007-07-01

    Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems, as it has they have been developed based on massive industrial experience of ferritic/martensitic steel replacing Mo and Nb of high chromium heat resistant martensitic steels (such as modified 9Cr-1Mo) with W and Ta, respectively. F82H and JLF-1 are RAFMs, which have been developed and studied in Japan and the various effects of irradiation were reported. F82H is designed with emphasis on high temperature property and weldability, and was provided and evaluated in various countries as a part of the IEA fusion materials development collaboration. The JAEA/US collaboration program also has been conducted with the emphasis on irradiation effects of F82H. Now, among the existing database for RAFMs the most extensive one is that for F82H. The objective of this paper is to review the R and D status of F82H and to identify the key technical issues for the fabrication of ITER Test Blanket Module (TBM) suggested from the recent achievements in Japan. It is desirable to make the status of RAFMs equivalent to commercial steels to use RAFMs as the ITER-TBM structural material. This would require demonstrating the reproducibility and weldability as well as providing the database. The excellent reproducibility of F82H has been demonstrated with four 5-ton-heats, and two of them were provided as F82H-IEA heats. It has been also proved that F82H could be provided as plates (thickness of 1.5 to 55 mm), pipes and rectangular tubes. It is also important to have the excellent weldability as the TBM has about 300m length of weld line, and it was proved through TIG, EB and YAG weld test performed in air atmosphere. Various mechanical and microstructural data have been accumulated including long-term tests such as creep rupture tests and aging tests. Although F82H is a well-perceived RAFM as the ITER-TBM structural material, some issues are

  8. Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

    2005-09-30

    Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the

  9. Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

    2005-09-30

    Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the

  10. The mechanical properties and microstructures of vanadium bearing high strength dual phase steels processed with continuous galvanizing line simulations

    Science.gov (United States)

    Gong, Yu

    For galvanized or galvannealed steels to be commercially successful, they must exhibit several attributes: (i) easy and inexpensive processing in the hot mill, cold mill and on the coating line, (ii) high strength with good formability and spot weldability, and (iii) good corrosion resistance. At the beginning of this thesis, compositions with a common base but containing various additions of V or Nb with or without high N were designed and subjected to Gleeble simulations of different galvanizing(GI), galvannealing(GA) and supercooling processing. The results revealed the phase balance was strongly influenced by the different microalloying additions, while the strengths of each phase were somewhat less affected. Our research revealed that the amount of austenite formed during intercritical annealing can be strongly influenced by the annealing temperature and the pre-annealing conditions of the hot band (coiling temperature) and cold band (% cold reduction). In the late part of this thesis, the base composition was a low carbon steel which would exhibit good spot weldability. To this steel were added two levels of Cr and Mo for strengthening the ferrite and increasing the hardenability of intercritically formed austenite. Also, these steels were produced with and without the addition of vanadium in an effort to further increase the strength. Since earlier studies revealed a relationship between the nature of the starting cold rolled microstructure and the response to CGL processing, the variables of hot band coiling temperature and level of cold reduction prior to annealing were also studied. Finally, in an effort to increase strength and ductility of both the final sheet (general formability) and the sheared edges of cold punched holes (local formability), a new thermal path was developed that replaced the conventional GI ferrite-martensite microstructure with a new ferrite-martensite-tempered martensite and retained austenite microstructure. The new

  11. Welding hot cracking in an austenitic stainless steel; Fissuration a chaud en soudage d'un acier inoxydable austenitique

    Energy Technology Data Exchange (ETDEWEB)

    Kerrouault, N

    2001-07-01

    The occurrence of hot cracking is linked to several conditions, in particular, the composition of the material and the local strains due to clambering. The aim of this study is to better analyse the implied mechanisms and to lead to a local thermomechanical criterion for hot cracking. The example studied is an AISI 321-type stainless steel (X10CrNiTi18-12) strongly prone to cracking. Two weldability tests are studied: - the first one consists in carrying out a fusion line by the TIG process on a thin sheet. In the case of the defect occurrence, the crack is longitudinal and follows the back of the molten bath. The influence of the operating conditions welding (speed, welding heat input, width test sample) is studied. - the second one is the Varestraint test. It is widely used to evaluate the sensitivity of a material to hot cracking. It consists in loading the material by bending during a fusion line by the TIG process and in characterising the defects quantity (length, number). Various thermal and mechanical instrumentation methods were used. The possibilities of a local instrumentation instrumentation being limited because of the melting, the experimental results were complemented by a numerical modelling whose aim is to simulate the thermomechanical evolution of the loading thanks to the finite element analysis code ABAQUS. First, the heat input for thermal simulation is set by the use of an inverse method in order to optimise the energy deposit mode during welding in the calculation. Then, the mechanical simulation needs the input of a constitutive law that fits the mechanical behaviour over a wide temperature range from ambient to melting temperature. Thus, a mechanical characterization is performed by selecting strain values and strain rates representative of what the material undergoes during the tests. The results come from tensile and compressive tests and allow to settle an elasto-visco-plastic constitutive law over temperatures up to liquidus. Once

  12. Materials Design for Joinable, High Performance Aluminum Alloys

    Science.gov (United States)

    Glamm, Ryan James

    An aluminum alloy compatible with friction stir welding is designed for automotive and aerospace structural applications. Current weldable automotive aluminum alloys do not possess the necessary strength to meet safety standards and therefore are not able to replace steel in the automotive body. Significant weight savings could be achieved if steel components are replaced with aluminum. Current aerospace alloys are not weldable, requiring machining of large pieces that are then riveted together. If an aerospace alloy could be friction stir welded, smaller pieces could be welded, reducing material waste. Using a systems approach for materials design, property goals are set from performance objectives. From previous research and computational predictions, a structure is designed for a prototype alloy containing dynamic precipitates to readily dissolve and re-precipitate and high stability precipitates to resist dissolution and coarsening in the weld region. It is found that a Ag modified Al-3.9Mg-0.04Cu (at. %) alloy enhanced the rate and magnitude of hardening during ageing, both beneficial effects for dynamic precipitation. In the same alloy, ageing at 350°C results in hardening from Al 3(Sc,Zr) precipitates. Efforts to effectively precipitate both populations simultaneously are unsuccessful. The Al3(Sc,Zr) precipitation hardened prototype is friction stir processed and no weak zones are found in the weld hardness profile. An aerospace alloy design is proposed, utilizing the dual precipitate structure shown in the prototype. The automotive alloy is designed using a basic strength model with parameters determined from the initial prototype alloy analysis. After ageing to different conditions, the alloy is put through a simulated heat affected zone thermal cycle with a computer controlled induction heater. The aged samples lose hardness from the weld cycle but recover hardness from a post weld heat treatment. Atom probe tomography and transmission electron

  13. Heavy steel casting components for power plants 'mega-components' made of high Cr-steels

    Energy Technology Data Exchange (ETDEWEB)

    Hanus, Reinhold [voestalpine Giesserei Linz GmbH, Linz (Austria)

    2010-07-01

    Steel castings of creep resistant steels play a key role in fossil fuel fired power plants for highly loaded components in the high and intermediate pressure section of the turbines. Inner and outer casings, valve casings, inlet connections and elbows are examples of such critical components. The most important characteristic in a power plant is the efficiency, which mainly drives the CO2-emission. As a consequence of steadily improving power plant efficiencies and ever stricter emission standards, steam parameters become more critical and the creep resistance of the cast materials must also be constantly improved. The foundries voestalpine Giesserei Linz and voestalpine Giesserei Traisen participated in the development of the new 9-10% Cr-steels for application up to 625 C/650 C and in the THERMIE project where Ni-base alloys for 700 C-power plants were developed. Beside the material development in the European research projects the commercial production had to be established for industrial processes and the newly developed materials have to be transferred from research into the commercial production of heavy cast components. After selecting the most promising alloy from the laboratory melts, welding tests were performed - mostly with matching electrodes also produced within COST/THERMIE. Base material and welds were investigated in respect of microstructure, creep resistance, mechanical properties and weldability. Heat treatment investigations were also necessary for optimization of the mechanical properties. Based on the results of these studies, pilot components and plates for testing welding processes were cast in order to verify the castability and weldability of larger parts and to make any necessary adjustments to chemical composition, heat treatment or welding parameters. Parallel to the ongoing creep tests within COST/THERMIE-program, the newly developed steel grades were introduced into the commercial production of large components. This involved finding

  14. Steam Turbine Materials for Ultrasupercritical Coal Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, R.; Hawk, J.; Schwant, R.; Saha, D.; Totemeier, T.; Goodstine, S.; McNally, M.; Allen, D. B.; Purgert, Robert

    2009-06-30

    The Ultrasupercritical (USC) Steam Turbine Materials Development Program is sponsored and funded by the U.S. Department of Energy and the Ohio Coal Development Office, through grants to Energy Industries of Ohio (EIO), a non-profit organization contracted to manage and direct the project. The program is co-funded by the General Electric Company, Alstom Power, Siemens Power Generation (formerly Siemens Westinghouse), and the Electric Power Research Institute, each organization having subcontracted with EIO and contributing teams of personnel to perform the requisite research. The program is focused on identifying, evaluating, and qualifying advanced alloys for utilization in coal-fired power plants that need to withstand steam turbine operating conditions up to 760°C (1400°F) and 35 MPa (5000 psi). For these conditions, components exposed to the highest temperatures and stresses will need to be constructed from nickel-based alloys with higher elevated temperature strength than the highchromium ferritic steels currently used in today's high-temperature steam turbines. In addition to the strength requirements, these alloys must also be weldable and resistant to environmental effects such as steam oxidation and solid particle erosion. In the present project, candidate materials with the required creep strength at desired temperatures have been identified. Coatings that can resist oxidation and solid particle erosion have also been identified. The ability to perform dissimilar welds between nickel base alloys and ferritic steels have been demonstrated, and the properties of the welds have been evaluated. Results of this three-year study that was completed in 2009 are described in this final report. Additional work is being planned and will commence in 2009. The specific objectives of the future studies will include conducting more detailed evaluations of the weld-ability, mechanical properties and repair-ability of the selected candidate alloys for rotors

  15. Hybrid Al/steel-joints manufactured by ultrasound enhanced friction stir welding (USE-FSW): Process comparison, nondestructive testing and microscopic analysis

    Science.gov (United States)

    Thomä, M.; Wagner, G.; Straß, B.; Wolter, B.; Benfer, S.; Fürbeth, W.

    2017-03-01

    The process of friction stir welding (FSW) is an innovative joining technique, which proved its potential in joining dissimilar metals that are poorly fusion weldable. This ability opens a wide range for applications in industrial fields, where weight reduction by partial substitution of conventional materials through lightweight materials is a current central aim. As a consequence of this, the realization of aluminum / steel-joints is of great interest. For this material compound, several friction stir welds were carried out by different researchers for varying Al/steel-joints, whereas the definition of optimal process parameters as well as the increase of mechanical properties was in the focus of the studies. To achieve further improved properties for this dissimilar joint a newly developed hybrid process named “ultrasound enhanced friction stir welding (USE-FSW)” was applied. In this paper the resulting properties of Al/steel-joints using FSW and USE-FSW will be presented and compared. Furthermore, first results by using the nondestructive testing method “computer laminography” to analyze the developed joining area will be shown supplemented by detailed light-microscopic investigations, scanning electron microscopic analysis, and EDX.

  16. Q345R与SAF2507超级双相钢焊接及质量控制%Welding of Q345R and SAF2507 Duplex Stainless Steel and Quality Control

    Institute of Scientific and Technical Information of China (English)

    杨平平

    2015-01-01

    对国内应用较少、耐蚀性强的SAF2507超级双相钢的特点进行分析,对比Q345R与SAF2507焊接性,参考异种钢焊接,利用舍弗勒图选取合适焊材。针对Q345R与SAF2507超级双相钢焊接进行试验分析并归纳其焊接工艺,提出了防止缺陷产生的焊接方法和保证焊接质量的措施。%In this article, the features of deluxe stainless steel SAF2507, which is seldom used in China and is well anticorrosive, were analyzed. With the comparison of the weldabilities of Q345R and SAF2507 and the reference for welding of heterogeneous steels, the appropriate welding consumers were selected by using Schaeffler diagram. Welding tests for Q345R and SAF2507 were carried out. After the analysis and summarization of their welding procedures, the welding method which can protect the occurrence of welding defects and measures for controlling quality were proposed.

  17. Subtask 12B1: Welding development for V-Cr-Ti alloys

    Energy Technology Data Exchange (ETDEWEB)

    King, J.F.; Goodwin, G.M.; Grossbeck, M.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1995-03-01

    Development of the metallurgical and technological basis for the welding of thick sections of V-Cr-Ti alloys. The weldability and weldment properties of the V-5Cr-5Ti alloy have been evaluated. Results for the Sigmajig test of the vanadium alloy were similar to the cracking resistance of stainless steels, and indicates hot-cracking is unlikely to be a problem. Subsize Charpy test results for GTA weld metal in the as-welded condition have shown a significant reduction in toughness compared to the base metal. The weld metal toughness properties were restored to approximately that of the base metal after exposure to a PWHT 950{degrees}C. The subsize Charpy toughness results for the EB weld metal from this same heat of vanadium alloy has shown significant improvement in properties compared to the GTA weld metal and the base metal. Further testing and analysis will be conducted to more fully characterize the properties of weld metal for each welding process and develop a basic understanding of the cause of the toughness decrease in the GTA welds. 5 figs., 1 tab.

  18. Effect of Austenitic and Austeno-Ferritic Electrodes on 2205 Duplex and 316L Austenitic Stainless Steel Dissimilar Welds

    Science.gov (United States)

    Verma, Jagesvar; Taiwade, Ravindra V.

    2016-09-01

    This study addresses the effect of different types of austenitic and austeno-ferritic electrodes (E309L, E309LMo and E2209) on the relationship between weldability, microstructure, mechanical properties and corrosion resistance of shielded metal arc welded duplex/austenitic (2205/316L) stainless steel dissimilar joints using the combined techniques of optical, scanning electron microscope, energy-dispersive spectrometer and electrochemical. The results indicated that the change in electrode composition led to microstructural variations in the welds with the development of different complex phases such as vermicular ferrite, lathy ferrite, widmanstatten and intragranular austenite. Mechanical properties of welded joints were diverged based on compositions and solidification modes; it was observed that ferritic mode solidified weld dominated property wise. However, the pitting corrosion resistance of all welds showed different behavior in chloride solution; moreover, weld with E2209 was superior, whereas E309L exhibited lower resistance. Higher degree of sensitization was observed in E2209 weld, while lesser in E309L weld. Optimum ferrite content was achieved in all welds.

  19. Living Additive Manufacturing: Transformation of Parent Gels into Diversely Functionalized Daughter Gels Made Possible by Visible Light Photoredox Catalysis.

    Science.gov (United States)

    Chen, Mao; Gu, Yuwei; Singh, Awaneesh; Zhong, Mingjiang; Jordan, Alex M; Biswas, Santidan; Korley, LaShanda T J; Balazs, Anna C; Johnson, Jeremiah A

    2017-02-22

    Light-initiated additive manufacturing techniques typically rely on layer-by-layer addition or continuous extraction of polymers formed via nonliving, free radical polymerization methods that render the final materials "dead" toward further monomer insertion; the polymer chains within the materials cannot be reactivated to induce chain extension. An alternative "living additive manufacturing" strategy would involve the use of photocontrolled living radical polymerization to spatiotemporally insert monomers into dormant "parent" materials to generate more complex and diversely functionalized "daughter" materials. Here, we demonstrate a proof-of-concept study of living additive manufacturing using end-linked polymer gels embedded with trithiocarbonate iniferters that can be activated by photoinduced single-electron transfer from an organic photoredox catalyst in solution. This system enables the synthesis of a wide range of chemically and mechanically differentiated daughter gels from a single type of parent gel via light-controlled modification of the parent's average composition, strand length, and/or cross-linking density. Daughter gels that are softer than their parent, stiffer than their parent, larger but with the same modulus as their parent, thermally responsive, polarity responsive, healable, and weldable are all realized.

  20. On-plant test of TUV HCM12 and ASME T23 alloys for use as waterwall materials

    DEFF Research Database (Denmark)

    Karlsson, Asger; Rasmussen, Frands; Montgomery, Melanie

    2000-01-01

    The development of Ultra Super Critical power plants has emphasised the need for stronger alloys for use as water walls. For this purpose HCM12 and HCM2S have been tested at 2 Danish power plants. HCM12 and HCM2S have been tested for their weldability, for thermal fatigue properties...... and for their oxidation properties under steam conditions 435-520º C, 26-27 MPa. The test included application of different weld methods and testing of the mechanical properties of the weld seams. The weld parameters giving the optimal properties were chosen to manufacture two pieces of water wall (1 times 1.5 meter...... to the stress' which appear in the water walls of an USC plant. The exposure was performed in the stress region close to the yield strength limit and cracks appeared in one of the materials. The tests have revealed that HCM12 is difficult to weld but develops no thermal fatigue crack whereas HCM2S is easy...

  1. Tomographical process monitoring of laser transmission welding with OCT

    Science.gov (United States)

    Ackermann, Philippe; Schmitt, Robert

    2017-06-01

    Process control of laser processes still encounters many obstacles. Although these processes are stable, a narrow process parameter window during the process or process deviations have led to an increase on the requirements for the process itself and on monitoring devices. Laser transmission welding as a contactless and locally limited joining technique is well-established in a variety of demanding production areas. For example, sensitive parts demand a particle-free joining technique which does not affect the inner components. Inline integrated non-destructive optical measurement systems capable of providing non-invasive tomographical images of the transparent material, the weld seam and its surrounding areas with micron resolution would improve the overall process. Obtained measurement data enable qualitative feedback into the system to adapt parameters for a more robust process. Within this paper we present the inline monitoring device based on Fourier-domain optical coherence tomography developed within the European-funded research project "Manunet Weldable". This device, after adaptation to the laser transmission welding process is optically and mechanically integrated into the existing laser system. The main target lies within the inline process control destined to extract tomographical geometrical measurement data from the weld seam forming process. Usage of this technology makes offline destructive testing of produced parts obsolete. 1,2,3,4

  2. Effect of Welding Thermal Cycles on Microstructure and Mechanical Properties of Simulated Heat Affected Zone for a Weldox 1300 Ultra-High Strength Alloy Steel

    Directory of Open Access Journals (Sweden)

    Węglowski M. St.

    2016-03-01

    Full Text Available In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on microstructure and mechanical properties of heat affected zone (HAZ for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 ÷ 300 sec. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The microstructure of ultra-high strength steel is mainly composed of tempered martensite. The results show that the impact toughness and hardness decrease with increase of t8/5 under condition of a single thermal cycle in simulated HAZ. The increase of cooling time to 300 s causes that the microstructure consists of ferrite and bainite mixture. Lower hardness, for t8/5 ≥ 60 s indicated that low risk of cold cracking in HAZ for longer cooling time, exists.

  3. Building on knowledge base of sodium cooled fast spectrum reactors to develop materials technology for fusion reactors

    Science.gov (United States)

    Raj, Baldev; Rao, K. Bhanu Sankara

    2009-04-01

    The alloys 316L(N) and Mod. 9Cr-1Mo steel are the major structural materials for fabrication of structural components in sodium cooled fast reactors (SFRs). Various factors influencing the mechanical behaviour of these alloys and different modes of deformation and failure in SFR systems, their analysis and the simulated tests performed on components for assessment of structural integrity and the applicability of RCC-MR code for the design and validation of components are highlighted. The procedures followed for optimal design of die and punch for the near net shape forming of petals of main vessel of 500 MWe prototype fast breeder reactor (PFBR); the safe temperature and strain rate domains established using dynamic materials model for forming of 316L(N) and 9Cr-1Mo steels components by various industrial processes are illustrated. Weldability problems associated with 316L(N) and Mo. 9Cr-1Mo are briefly discussed. The utilization of artificial neural network models for prediction of creep rupture life and delta-ferrite in austenitic stainless steel welds is described. The usage of non-destructive examination techniques in characterization of deformation, fracture and various microstructural features in SFR materials is briefly discussed. Most of the experience gained on SFR systems could be utilized in developing science and technology for fusion reactors. Summary of the current status of knowledge on various aspects of fission and fusion systems with emphasis on cross fertilization of research is presented.

  4. Progress in thermomechanical control of steel plates and their commercialization

    Directory of Open Access Journals (Sweden)

    Kiyoshi Nishioka and Kazutoshi Ichikawa

    2012-01-01

    Full Text Available The water-cooled thermomechanical control process (TMCP is a technology for improving the strength and toughness of water-cooled steel plates, while allowing control of the microstructure, phase transformation and rolling. This review describes metallurgical aspects of the microalloying of steel, such as niobium addition, and discusses advantages of TMCP, for example, in terms of weldability, which is reduced upon alloying. Other covered topics include the development of equipment, distortions in steel plates, peripheral technologies such as steel making and casting, and theoretical modeling, as well as the history of property control in steel plate production and some early TMCP technologies. We provide some of the latest examples of applications of TMCP steel in various industries such as shipbuilding, offshore structures, building construction, bridges, pipelines, penstocks and cryogenic tanks. This review also introduces high heat-affected-zone toughness technologies, wherein the microstructure of steel is improved by the addition of fine particles of magnesium-containing sulfides and magnesium- or calcium-containing oxides. We demonstrate that thanks to ongoing developments TMCP has the potential to meet the ever-increasing demands of steel plates.

  5. Formation of Intermetallic Compounds During Explosive Welding

    Science.gov (United States)

    Greenberg, Bella A.; Ivanov, Mikhail A.; Pushkin, Mark S.; Inozemtsev, Alexei V.; Patselov, Alexander M.; Tankeyev, Anatoliy P.; Kuzmin, Sergey V.; Lysak, Vladimir I.

    2016-11-01

    Transition states between traditional, i.e., plain and wavy, shapes of the interface during explosive welding were studied. A sequence of the transition states was found for the studied copper-titanium and copper-tantalum joints. Some transition states are common for the joints under study, while others are only typical of the copper-titanium joints, due to sufficiently high solubility of original elements. A transition state has been found, during which cusps, even though they are solid phase, look like splashes on the water. The key role of these splashes is that they evidence the lower boundary of the `weldability window.' The study found certain self-organization processes of the cusps that cause them to turn into a quasi-wavy shape of the interface, and then, as the welding mode is intensified, into a wavy shape. The role of intermetallic compounds was analyzed, due to which a wave only consists of cusps in case mutual solubility of original metals is sufficiently high.

  6. Explosive Welding of Aluminum, Titanium and Zirconium to Copper Sheet Metal

    Science.gov (United States)

    Hegazy, A. A.; Mote, J. D.

    1985-01-01

    The main material properties affecting the explosive weldability of a certain metal combination are the yield strength, the ductility, the density and the sonic velocity of the two metals. Successful welding of the metal combination depends mainly on the correct choice of the explosive welding parameters; i.e., the stand off distance, the weight of the explosive charge relative to the weight of the flyer plate and the detonation velocity of the explosive. Based on the measured and the handbook values of the properties of interest, the explosive welding parameters were calculated and the arrangements for the explosive welding of the Al alloy 6061-T6, titanium and zirconium to OFHC copper were determined. The relatively small sheet metal thickness (1/8") and the fact that the thickness of the explosive layer must exceed a certain minimum value were considered during the determination of the explosive welding conditions. The results of the metallographic investigations and the measurements of the shear strength at the interface demonstrate the usefulness of these calculations to minimize the number of experimental trials.

  7. Aluminum alloy production for the reinforcement of the CMS conductor

    CERN Document Server

    Sequeira-Lopes-Tavares, S; Campi, D; Curé, B; Horváth, I L; Riboni, P; Sgobba, Stefano; Smith, R P

    2002-01-01

    The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the Large Hadron Collider (LHC) project at CERN. The design field of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. To reinforce the high-purity (99.998%) Al-stabilized conductor of the magnet against the magnetic loadings experienced during operation at 4.2 K, two continuous sections of Al-alloy (AA) reinforcement are Electron Beam (EB) welded to it. The reinforcements have a section of 24*18 mm and are produced in continuous 2.55 km lengths. The alloy EN AW-6082 has been selected for the reinforcement due to its excellent extrudability, high strength in the precipitation hardened states, high toughness and strength at cryogenic temperature and good EB weldability. Each of the continuous lengths of the reinforcement is extruded billet on billet and press quenched on-line from the extrusion temperature in an industrial extrusion plant. In order to insure the ready EB welda...

  8. An improved billet on billet extrusion process of continuous aluminium alloy shapes for cryogenic applications in the Compact Muon Solenoid experiment

    CERN Document Server

    Tavares, S S

    2003-01-01

    The Compact Muon Solenoid (CMS) is one of the experiments being designed in the framework of the Large Hadron Collider accelerator at CERN. CMS will contain the largest and the most powerful superconducting solenoid magnet ever built in terms of stored energy. It will work at 4.2 K, will have a magnetic length of 12.5 m, with a free bore of 6m and will be manufactured as a layered and modular structure of NbTi cables embedded in a high purity (99.998%) Al- stabiliser. Each layer consists of a wound continuous length of 2.55 km. In order to withstand the high electromagnetic forces, two external aluminium alloy reinforcing sections are foreseen. These reinforcements, of 24 mm multiplied by 18 mm cross-section, will be continuously electron beam (EB) welded to the pure Al-stabiliser. The alloy EN AW-6082 has been selected for the reinforcements due to its excellent extrudability, high strength in the precipitation hardened state, high toughness and strength at cryogenic temperatures and ready EB weldability. Ea...

  9. Low activation steels welding with PWHT and coating for ITER test blanket modules and DEMO

    Science.gov (United States)

    Aubert, P.; Tavassoli, F.; Rieth, M.; Diegele, E.; Poitevin, Y.

    2011-02-01

    EUROFER weldability is investigated in support of the European material properties database and TBM manufacturing. Electron Beam, Hybrid, laser and narrow gap TIG processes have been carried out on the EUROFER-97 steel (thickness up to 40 mm), a reduced activation ferritic-martensitic steel developed in Europe. These welding processes produce similar welding results with high joint coefficients and are well adapted for minimizing residual distortions. The fusion zones are typically composed of martensite laths, with small grain sizes. In the heat-affected zones, martensite grains contain carbide precipitates. High hardness values are measured in all these zones that if not tempered would degrade toughness and creep resistance. PWHT developments have driven to a one-step PWHT (750 °C/3 h), successfully applied to joints restoring good material performances. It will produce less distortion levels than a full austenitization PWHT process, not really applicable to a complex welded structure such as the TBM. Different tungsten coatings have been successfully processed on EUROFER material. It has shown no really effect on the EUROFER base material microstructure.

  10. Chemical and microstructural diversity of steel grades

    Directory of Open Access Journals (Sweden)

    Zorc, B.

    2002-12-01

    Full Text Available The aim of the paper is to show, using theoretical and practical analyses, chemical and microstructural differences among individual types of steel grades 355 found in the market. The mechanical properties required for these steels are achieved by alloying or thermomechanical treatment. It was found that the individual types of this steel are poorly weldable, particularly those of large thickness.

    El objetivo del artículo es presentar, en base a un análisis teórico y práctico, las diferencias químicas y microestructurales entre los diferentes tipos de aceros calidad 355 que pueden encontrarse en el mercado. Las características mecánicas requeridas en estos aceros se consiguen con aleaciones, o bien a través de tratamientos termo-mecánicos.Se ha llegado a la conclusión de que determinados tipos de acero son más difíciles de soldar, en especial cuando se trata de espesores grandes.

  11. Evaluation of iron aluminide weld overlays for erosion - corrosion resistant boiler tube coatings in low NO{sub x} boilers

    Energy Technology Data Exchange (ETDEWEB)

    DuPont, J.N.; Banovic, S.W.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States)

    1996-08-01

    Low NOx burners are being installed in many fossil fired power plants in order to comply with new Clean Air Regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion is often enhanced and premature tube failures can occur. Failures due to oxidation and solid particle erosion are also a concern. A program was initiated in early 1996 to evaluate the use of iron aluminide weld overlays for erosion/corrosion protection of boiler tubes in Low NOx boilers. Composite iron/aluminum wires will be used with the Gas Metal Arc Welding (GMAW) process to prepare overlays on boiler tubes steels with aluminum contents from 8 to 16wt%. The weldability of the composite wires will be evaluated as a function of chemical composition and welding parameters. The effect of overlay composition on corrosion (oxidation and sulfidation) and solid particle erosion will also be evaluated. The laboratory studies will be complemented by field exposures of both iron aluminide weld overlays and co-extruded tubing under actual boiler conditions.

  12. Investigation of the precipitation mechanism in HAZ of super-martensitic stainless steels. Two-pass weld simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ladanova, Elena; Solberg, Jan K. [The Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Rogne, Trond [SINTEF Materials and Chemistry, N-7465 Trondheim (Norway)

    2004-07-01

    Weld simulation is widely used for studying weldability of steels. Mostly, HAZ of one pass welding is simulated, and the produced specimens are mainly used for mechanical testing. Another way of applying weld simulation is to find the temperature history giving a certain microstructure observed in the HAZ of a real multipass weld. In the present work, a two-pass weld simulation was used to investigate the precipitation mechanism of carbides in the HAZ of two super-martensitic stainless steels. Previously, a model for carbide precipitation was suggested. According to this model, a reheating of the HAZ in the martensitic stage is needed to provoke strong carbide formation. In the present work, the peak temperatures of the first and second heating pass and also the temperature of the inter-pass holding were varied together with holding time during the reheat (the second pass). The most favourable heating regime for grain boundary carbide precipitation was found for both investigated steels. In addition, measurements of the chromium content across prior austenite grain boundaries were done for one of the investigated steels. The thin foils were prepared from the specimens where the strongest carbide precipitation was observed. (authors)

  13. Narrow gap HST welding process and its application to candidate pipe material for 700 C USC boiler component

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Gang; Sato, Takashi; Fukuda, Yuji [Babcock-Hitachi K.K., Hiroshima (Japan). Kure Research Lab.; Mitsuhata, Koichi [Babcock-Hitachi K.K., Hiroshima (Japan). Kure Div.

    2008-07-01

    Increasing steam temperature and pressure conditions of 700 C USC (Ultra Super Critical) power plants under consideration require the adoption of Ni-based alloys. One of the most crucial issues for the application of 700 C USC power plants is the establishment of welding technology for the thick-walled components. This paper reports the research results on the practicability of candidate material for the thickwalled components. The weld test was conducted on Ni-based Alloy617 (52Ni-22Cr- 13Co-9Mo-Ti-Al) by using the narrow gap HST (Hot wire Switching TIG) welding process developed by Babcock-Hitachi K.K with the matching filler wire of Alloy617. The weldability and strength properties of weld joint were examined. The sound weld joint was achieved. The advantages of narrow gap HST welding process for the thick-walled components of Ni-based alloy were discussed from the viewpoints of weld metal chemical composition and creep rupture strength. Due to the good shielding effect, the melting loss of alloy elements in the weld consumable during the narrow gap HST welding procedure was suppressed successfully. The narrow gap HST weld joint showed comparable strength with the parent metal. (orig.)

  14. Influence of Heat Input on Microstructure and Toughness Properties in Simulated CGHAZ of X80 Steel Manufactured Using High-Temperature Processing

    Science.gov (United States)

    Zhu, Zhixiong; Han, Jian; Li, Huijun

    2015-11-01

    To determine and demonstrate the weldability of high-Nb high-temperature processed (HTP) steels and provide extremely valuable information for future line pipe steel design and general steel manufacture, in the current study the toughness in simulated coarse-grained heat-affected zone (CGHAZ) of an X80 grade steel manufactured using HTP was evaluated. The simulated CGHAZs subjected to thermal cycles with various heat inputs (HIs) (0.8 to 5.0 kJ/mm) were produced using a Gleeble 3500 simulator. The microstructures and corresponding mechanical properties were investigated by means of optical microscopy, scanning electron microscopy, electron backscatter diffraction, hardness testing, and Charpy V-notch (CVN) testing. The microstructural examination shows that the simulated CGHAZs consisted of a bainite-dominant microstructure and relatively low amount (testing suggest that superior toughness can be achieved in the studied range of HIs (0.8 to 5 kJ/mm). This is thought to be associated with the combined effects of bainitic microstructure and low M-A fraction as well as comparatively fine austenite grain size in the studied CGHAZs.

  15. Influence of Yb:YAG Laser Beam Parameters on Haynes 188 Weld Fusion Zone Microstructure and Mechanical Properties

    Science.gov (United States)

    Graneix, Jérémie; Beguin, Jean-Denis; Alexis, Joël; Masri, Talal

    2017-08-01

    The weldability of 1.2 mm thick Haynes 188 alloy sheets by a disk Yb:YAG laser welding was examined. Butt joints were made, and the influence of parameters such as power, size, and shape of the spot, welding speed, and gas flow has been investigated. Based on an iconographic correlation approach, optimum process parameters were determined. Depending on the distribution of the power density (circular or annular), acceptable welds were obtained. Powers greater than 1700 W, welding speeds higher than 3.8 m mm-1, and spot sizes between 160 and 320 μm were needed in the circular (small fiber) configuration. By comparison, the annular (large fiber) configuration required a power as high as 2500 W, and a welding speed less than 3.8 m min-1. The mechanical properties of the welds depended on their shape and microstructure, which in turn depended on the welding conditions. The content of carbides, the proportion of areas consisting of cellular and dendritic substructures, and the size of these substructures were used to explain the welded joint mechanical properties.

  16. Analysis and Comparison of Friction Stir Welding and Laser Assisted Friction Stir Welding of Aluminum Alloy.

    Science.gov (United States)

    Campanelli, Sabina Luisa; Casalino, Giuseppe; Casavola, Caterina; Moramarco, Vincenzo

    2013-12-18

    Friction Stir Welding (FSW) is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW) is a combination in which the FSW is the dominant welding process and the laser pre-heats the weld. In this work FSW and LAFSW tests were conducted on 6 mm thick 5754H111 aluminum alloy plates in butt joint configuration. LAFSW is studied firstly to demonstrate the weldability of aluminum alloy using that technique. Secondly, process parameters, such as laser power and temperature gradient are investigated in order to evaluate changes in microstructure, micro-hardness, residual stress, and tensile properties. Once the possibility to achieve sound weld using LAFSW is demonstrated, it will be possible to explore the benefits for tool wear, higher welding speeds, and lower clamping force.

  17. Characterization the microstructure of pulsed Nd:YAG welding method in low frequencies; correlation with tensile and fracture behavior in laser-welded nitinol joints

    Science.gov (United States)

    Shojaei Zoeram, Ali; Rahmani, Aida; Asghar Akbari Mousavi, Seyed Ali

    2017-05-01

    The precise controllability of heat input in pulsed Nd:YAG welding method provided by two additional parameters, frequency and pulse duration, has made this method very promising for welding of alloys sensitive to heat input. The poor weldability of Ti-rich nitinol as a result of the formation of Ti2Ni IMC has deprived us of the unique properties of this alloy. In this study, to intensify solidification rate during welding of Ti-rich nitinol, pulsed Nd:YAG laser beam in low frequency was employed in addition to the employment of a copper substrate. Specific microstructure produced in this condition was characterized and the effects of this microstructure on tensile and fracture behavior of samples welded by two different procedures, full penetration and double-sided method with halved penetration depth for each side were investigated. The investigations revealed although the combination of low frequencies, the use of a high thermal conductor substrate and double-sided method eliminated intergranular fracture and increased tensile strength, the particular microstructure, built in the pulsed welding method in low frequencies, results to the formation of the longitudinal cracks during the first stages of tensile test at weld centerline. This degrades tensile strength of welded samples compared to base metal. The results showed samples welded in double-sided method performed much better than samples welded in full penetration mode.

  18. Dissimilar steel welding and overlay covering with nickel based alloys using SWAM (Shielded Metal Arc Welding) and GTAW (Gas Tungsten Arc Welding) processes in the nuclear industry

    Energy Technology Data Exchange (ETDEWEB)

    Arce Chilque, Angel Rafael [Centro Tecnico de Engenharia e Inovacao Empresarial Ltda., Belo Horizonte, MG (Brazil); Bracarense, Alexander Queiroz; Lima, Luciana Iglesias Lourenco [Federal University of Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Quinan, Marco Antonio Dutra; Schvartzman, Monica Maria de Abreu Mendonca [Nuclear Technology Development Centre (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Marconi, Guilherme [Federal Center of Technological Education (CEFET-MG), Belo Horizonte, MG (Brazil)

    2009-07-01

    This work presents the welding of dissimilar ferritic steel type A508 class 3 and austenitic stainless steel type AISI 316 L using Inconel{sup R} 600 (A182 and A82) and overlay covering with Inconel{sup R} 690 (A52) as filler metal. Dissimilar welds with these materials without defects and weldability problems such as hot, cold, reheat cracking and Ductility Dip Crack were obtained. Comparables mechanical properties to those of the base metal were found and signalized the efficiency of the welding procedure and thermal treatment selected and used. This study evidences the importance of meeting compromised properties between heat affected zone of the ferritic steel and the others regions presents in the dissimilar joint, to elaborate the dissimilar metal welding procedure specification and weld overlay. Metallographic studies with optical microscopy and Vickers microhardness were carried out to justified and support the results, showing the efficiency of the technique of elaboration of dissimilar metal welding procedure and overlay. The results are comparables and coherent with the results found by others. Some alternatives of welding procedures are proposed to attain the efficacy. Further studies are proposed like as metallographic studies of the fine microstructure, making use, for example, of scanning electron microscope (SEM adapted with an EDS) to explain looking to increase the resistance to primary water stress corrosion (PWSCC) in nuclear equipment. (author)

  19. Development of advanced low alloy steel for nuclear RPV

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H. C.; Shin, K. S.; Lee, S. H.; Lee, B. J. [Seoul National Univ., Seoul (Korea)

    2000-04-01

    Low carbon low alloy steels are used in nuclear power plants as pressure vessel, steam generator, etc. Nuclear pressure vessel material requires good combination of strength/ toughness, good weldability and high resistance to neutron irradiation and corrosion fatigue. For SA508III steels, most widely used in the production of nuclear power plant, attaining toughness is more difficult than strength. When taking into account the loss of toughness due to neutron irradiation, attaining as low transition temperature as possible prior to operation is a critical task in the production of nuclear pressure vessels. In the present study, we investigated detrimental microstructural features of SA508III steels to toughness, then alloy design directions to achieve improved mechanical properties were devised. The next step of alloy design was determined based on phase equilibrium thermodynamics and obtained results. Low carbon low alloy steels having low transition temperatures with enough strength and hardenability were developed. Microstructure and mechanical properties of HAZ of SA508III steels and alloy designed steels were investigated. 22 refs., 147 figs., 38 tabs. (Author)

  20. The effect of grain boundary segregation of boron in cast alloy 718 on HAZ microfissuring -- a SIMS analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huang, X.; Chaturvedi, M.C. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Mechanical and Industrial Engineering; Richards, N.L. [Bristol Aerospace Ltd., Winnipeg, Manitoba (Canada); Jackman, J. [CANMET, Ottawa, Ontario (Canada)

    1997-08-01

    Secondary ion mass spectroscopy (SIMS) has been used to examine grain boundary segregation in cast alloy 718. The relationship between the boron segregation and the microfissuring tendency in heat affected zones (HAZ) around electron beam welds is discussed in this study. It is concluded that two types of segregation, namely equilibrium and non-equilibrium segregation, occurred during the homogenization heat treatment of the base material. Water quenching after the homogenization treatment inhibited non-equilibrium segregation of boron and other trace elements owing to insufficient time for diffusion of solute-vacancy complexes to occur. Intermediate cooling rates such as air cooling enhanced both non-equilibrium and equilibrium segregation, since equilibrium segregation occurred during holding at the heat treatment temperature. The value of net segregation produced by a combination of equilibrium segregation and non-equilibrium segregation varied with temperature in a U-shape. The nature of the grain boundary in the cast alloy was examined by using an electron backscattered diffraction (EBSD) technique and it was found that 93% of the grain boundaries were of the random type ({Sigma} > 49). The weldability of this alloy was found to be closely related to the grain boundary segregation of boron, i.e., the variation of HAZ total crack length (TCL) with pre-welding heat treatment temperatures has a trend similar to that of boron segregation with temperature after air cooling. Mechanisms for the effect of boron on HAZ microfissuring have been proposed.

  1. The Study of Heat Treatment Effects on Chromium Carbide Precipitation of 35Cr-45Ni-Nb Alloy for Repairing Furnace Tubes

    Directory of Open Access Journals (Sweden)

    Nakarin Srisuwan

    2016-01-01

    Full Text Available This paper presents a specific kind of failure in ethylene pyrolysis furnace tubes. It considers the case in which the tubes made of 35Cr-45Ni-Nb high temperature alloy failed to carburization, causing creep damage. The investigation found that used tubes became difficult to weld repair due to internal carburized layers of the tube. The microstructure and geochemical component of crystallized carbide at grain boundary of tube specimens were characterized by X-ray diffractometer (XRD, scanning electron microscopy (SEM with back-scattered electrons mode (BSE, and energy dispersive X-ray spectroscopy (EDS. Micro-hardness tests was performed to determine the hardness of the matrix and the compounds of new and used tube material. The testing result indicated that used tubes exhibited a higher hardness and higher degree of carburization compared to those of new tubes. The microstructure of used tubes also revealed coarse chromium carbide precipitation and a continuous carbide lattice at austenite grain boundaries. However, thermal heat treatment applied for developing tube weld repair could result in dissolving or breaking up chromium carbide with a decrease in hardness value. This procedure is recommended to improve the weldability of the 35Cr-45Ni-Nb used tubes alloy.

  2. First Annual Progress Report on Radiation Tolerance of Controlled Fusion Welds in High Temperature Oxidation Resistant FeCrAl Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hu, Xunxiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    The present report summarizes and discusses the first year efforts towards developing a modern, nuclear grade FeCrAl alloy designed to have enhanced radiation tolerance and weldability under the Department of Energy (DOE) Nuclear Energy Enabling Technologies (NEET) program. Significant efforts have been made within the first year of this project including the fabrication of seven candidate FeCrAl alloys with well controlled chemistry and microstructure, the microstructural characterization of these alloys using standardized and advanced techniques, mechanical properties testing and evaluation of base alloys, the completion of welding trials and production of weldments for subsequent testing, the design of novel tensile specimen geometry to increase the number of samples that can be irradiated in a single capsule and also shorten the time of their assessment after irradiation, the development of testing procedures for controlled hydrogen ingress studies, and a detailed mechanical and microstructural assessment of weldments prior to irradiation or hydrogen charging. These efforts and research results have shown promise for the FeCrAl alloy class as a new nuclear grade alloy class.

  3. Microstructure, mechanical properties and texture of an AA6061/AA5754 composite fabricated by cross accumulative roll bonding

    Energy Technology Data Exchange (ETDEWEB)

    Verstraete, K., E-mail: kevin.verstraete@u-psud.fr [Université Paris-Sud, SP2M, ICMMO, UMR CNRS 8182, 91405 Orsay Cedex (France); Helbert, A.L. [Université Paris-Sud, SP2M, ICMMO, UMR CNRS 8182, 91405 Orsay Cedex (France); Brisset, F. [Université Paris-Sud, ICMMO, UMR CNRS 8182, 91405 Orsay Cedex (France); Benoit, A.; Paillard, P. [Institut des Matériaux Jean Rouxel (IMN), UMR 6502, Polytech’Nantes, Nantes Cedex (France); Baudin, T. [Université Paris-Sud, SP2M, ICMMO, UMR CNRS 8182, 91405 Orsay Cedex (France)

    2015-07-29

    AA6061 alloy is a widely used material in the automotive and aerospace industries, but is prone to hot cracking, which limits its weldability. To prevent this phenomenon, the AA6061/AA5754 composite was formed using a severe plastic deformation technique, Cross Accumulative Roll Bonding (CARB), at an elevated temperature (350 °C) to ensure good bonding between layers. This technique was efficient to maintain a small grain size, even under the process temperature conditions, and consequently, preserve good mechanical properties. The composite had better mechanical properties than the initial aluminium alloys. Microstructure and texture remained stable after two cycles and yield stress tended towards an equal value in the rolling and the transverse directions. After two cycles, the main component was the {001}〈110〉 rotated Cube, which was maintained for up to 10 cycles. Diffusion was more effective as the strain increased. Finally, a tungsten inert gas (TIG) welding process was performed on the composite and confirmed resistance to hot cracking.

  4. Neutronic design studies of a conceptual DCLL fusion reactor for a DEMO and a commercial power plant

    Science.gov (United States)

    Palermo, I.; Veredas, G.; Gómez-Ros, J. M.; Sanz, J.; Ibarra, A.

    2016-01-01

    Neutronic analyses or, more widely, nuclear analyses have been performed for the development of a dual-coolant He/LiPb (DCLL) conceptual design reactor. A detailed three-dimensional (3D) model has been examined and optimized. The design is based on the plasma parameters and functional materials of the power plant conceptual studies (PPCS) model C. The initial radial-build for the detailed model has been determined according to the dimensions established in a previous work on an equivalent simplified homogenized reactor model. For optimization purposes, the initial specifications established over the simplified model have been refined on the detailed 3D design, modifying material and dimension of breeding blanket, shield and vacuum vessel in order to fulfil the priority requirements of a fusion reactor in terms of the fundamental neutronic responses. Tritium breeding ratio, energy multiplication factor, radiation limits in the TF coils, helium production and displacements per atom (dpa) have been calculated in order to demonstrate the functionality and viability of the reactor design in guaranteeing tritium self-sufficiency, power efficiency, plasma confinement, and re-weldability and structural integrity of the components. The paper describes the neutronic design improvements of the DCLL reactor, obtaining results for both DEMO and power plant operational scenarios.

  5. Effect of Austenitic and Austeno-Ferritic Electrodes on 2205 Duplex and 316L Austenitic Stainless Steel Dissimilar Welds

    Science.gov (United States)

    Verma, Jagesvar; Taiwade, Ravindra V.

    2016-11-01

    This study addresses the effect of different types of austenitic and austeno-ferritic electrodes (E309L, E309LMo and E2209) on the relationship between weldability, microstructure, mechanical properties and corrosion resistance of shielded metal arc welded duplex/austenitic (2205/316L) stainless steel dissimilar joints using the combined techniques of optical, scanning electron microscope, energy-dispersive spectrometer and electrochemical. The results indicated that the change in electrode composition led to microstructural variations in the welds with the development of different complex phases such as vermicular ferrite, lathy ferrite, widmanstatten and intragranular austenite. Mechanical properties of welded joints were diverged based on compositions and solidification modes; it was observed that ferritic mode solidified weld dominated property wise. However, the pitting corrosion resistance of all welds showed different behavior in chloride solution; moreover, weld with E2209 was superior, whereas E309L exhibited lower resistance. Higher degree of sensitization was observed in E2209 weld, while lesser in E309L weld. Optimum ferrite content was achieved in all welds.

  6. An Efficient and Versatile Means for Assembling and Manufacturing Systems in Space

    Science.gov (United States)

    Dorsey, John T.; Doggett, William R.; Hafley, Robert A.; Komendera, Erik; Correll, Nikolaus; King, Bruce

    2012-01-01

    Within NASA Space Science, Exploration and the Office of Chief Technologist, there are Grand Challenges and advanced future exploration, science and commercial mission applications that could benefit significantly from large-span and large-area structural systems. Of particular and persistent interest to the Space Science community is the desire for large (in the 10- 50 meter range for main aperture diameter) space telescopes that would revolutionize space astronomy. Achieving these systems will likely require on-orbit assembly, but previous approaches for assembling large-scale telescope truss structures and systems in space have been perceived as very costly because they require high precision and custom components. These components rely on a large number of mechanical connections and supporting infrastructure that are unique to each application. In this paper, a new assembly paradigm that mitigates these concerns is proposed and described. A new assembly approach, developed to implement the paradigm, is developed incorporating: Intelligent Precision Jigging Robots, Electron-Beam welding, robotic handling/manipulation, operations assembly sequence and path planning, and low precision weldable structural elements. Key advantages of the new assembly paradigm, as well as concept descriptions and ongoing research and technology development efforts for each of the major elements are summarized.

  7. 提高小型镀铅锡合金焊接件抗氧化性的工艺研究%Process Research on Promoting Oxidation Resistance of Lead Tin Alloy Weldment

    Institute of Scientific and Technical Information of China (English)

    杜楠; 付明

    2012-01-01

    Some process experiments were made to solve the problem of lead tin alloy parts oxidation on surface after being stored a period of time. Based on these experiments, the protection film with anti-tarnish was made. The problems were solved that the lead tin alloy parts could not be heated melting treatment with glycerin, were easy to be oxidated and weldability decrease.%为解决镀铅锡零件在存放一定时间后其表面容易被氧化这一问题,进行了一系列工艺对比试验,保证镀层结晶细致、再加上化学钝化处理、并在此基础上试验出了防变色能力较好的保护膜,基本上解决了标准件镀铅锡合金后无法进行甘油热熔处理、镀层表面容易氧化,焊接性能下降的问题.

  8. Iron aluminide weld overlay coatings for boiler tube protection in coal-fired low NOx boilers

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center

    1997-12-01

    Iron aluminide weld overlay coatings are currently being considered for enhanced sulfidation resistance in coal-fired low NO{sub x} boilers. The use of these materials is currently limited due to hydrogen cracking susceptibility, which generally increases with an increase in aluminum concentration of the deposit. The overall objective of this program is to attain an optimum aluminum content with good weldability and improved sulfidation resistance with respect to conventional materials presently in use. Research has been initiated using Gas Tungsten Arc Welding (GTAW) in order to achieve this end. Under different sets of GTAW parameters (wire feed speed, current), both single and multiple pass overlays were produced. Characterization of all weldments was conducted using light optical microscopy, scanning electron microscopy, and electron probe microanalysis. Resultant deposits exhibited a wide range of aluminum contents (5--43 wt%). It was found that the GTAW overlays with aluminum contents above {approximately}10 wt% resulted in cracked coatings. Preliminary corrosion experiments of 5 to 10 wt% Al cast alloys in relatively simple H{sub 2}/H{sub 2}S gas mixtures exhibited corrosion rates lower than 304 stainless steel.

  9. Safety-relevant components made of low-iron, Al-base die-casting alloys; Sicherheitsbauteile aus eisenarmen Aluminium-Druckgusslegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Hielscher, U. [Aluminium Rheinfelden GmbH, Rheinfelden (Germany)

    1999-07-01

    The modern automotive engineering requirements to be met by die-casting aluminium alloys with respect to the microstructure, casting process, compatibility with operating media, and weldability are such that they cannot be met by conventional alloys. Therefore, there was a quest for novel alloys, which at the Aluminium Rheinfelden company has led to the development of two low-iron alloys: Silafont-36 (AlSi9MgMnSr), and Magsimal-59 (AlMg5Si2Mn). The materials properties and some applications are explained. (orig./MM) [German] Von der Automobilindustrie werden an die Aluminiumguss-Legierungen folgende Anforderungen gestellt: 1. sehr duktiles Gefuege, 2. gute Giessbarkeit fuer das Druckgiessverfahren, 3. Vertraeglichkeit mit den Eisenwerkstoffen der Giesswerkzeuge sowie Trenn- und Schmierstoffen, 4. gute Schweissbarkeit und gute Boerdelbarkeit. Die herkoemmlichen Gusslegierungen erfuellen diese Anforderungen nicht; der Aluminium Rheinfelden gelang die Entwicklung von zwei eisenarmen Legierungen: Silafont-36 (AlSi9MgMnSr) und Magsimal-59 (AlMg5Si2Mn). (orig.)

  10. PENGARUH BESAR ARUS LISTRIK DENGAN MENGGUNAKAN ELEKTRODA SMAW TERHADAP KEKUATAN SAMBUNGAN LAS BUTT JOINT PADA PLAT MILD STEEL

    Directory of Open Access Journals (Sweden)

    Sarjito Jokosisworo

    2012-03-01

    Full Text Available The influence of mechanic disposition, is one of the factor influence ship strength. This influence can be test by mechanical test in welding butt joint. The result test database analysis can be conclude that very helpful to increase safety and quality butt joint. With steel specification C= 0,15%, Si= 0,24%, Mn= 0,88%,P= 0,018%, S= 0,034%. This material give a 90, 110, 125 ampere with SMAW AC electrode diameter 3,2 mm x 350 mm with V root and 600 angle In the fabrication of mild steel products, components or equipment, manufacturers employ welding as the principal joining method. Mild steel are weldable materials, and a welded joint can provide optimum corrosion resistance, strength, and fabrication economy. However, designers should recognize that any metal, including stainless steels, may undergo certain changes during welding. It is necessary, therefore, to exercise a reasonable degree of care during welding to minimize or prevent any deleterious effects that may occur, and to preserve the same degree of corrosion resistance and strength in weld zone that is an intheren part of the base metal

  11. Progress in thermomechanical control of steel plates and their commercialization

    Science.gov (United States)

    Nishioka, Kiyoshi; Ichikawa, Kazutoshi

    2012-04-01

    The water-cooled thermomechanical control process (TMCP) is a technology for improving the strength and toughness of water-cooled steel plates, while allowing control of the microstructure, phase transformation and rolling. This review describes metallurgical aspects of the microalloying of steel, such as niobium addition, and discusses advantages of TMCP, for example, in terms of weldability, which is reduced upon alloying. Other covered topics include the development of equipment, distortions in steel plates, peripheral technologies such as steel making and casting, and theoretical modeling, as well as the history of property control in steel plate production and some early TMCP technologies. We provide some of the latest examples of applications of TMCP steel in various industries such as shipbuilding, offshore structures, building construction, bridges, pipelines, penstocks and cryogenic tanks. This review also introduces high heat-affected-zone toughness technologies, wherein the microstructure of steel is improved by the addition of fine particles of magnesium-containing sulfides and magnesium- or calcium-containing oxides. We demonstrate that thanks to ongoing developments TMCP has the potential to meet the ever-increasing demands of steel plates.

  12. Development of API 5L X70 and X80 in the Brazilian Vallourec and Mannesmann Tubes industry; Desenvolvimento de acos API 5L X70 e X80 na Vallourec e Mannesmann Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Julio M. Silveira e; Carvalho, Ricardo N. de [Vallourec and Mannesmann Tubes - V e M do Brasil, Belo Horizonte, MG (Brazil)

    2000-07-01

    The demand for seamless pipes with resistance higher than those for API 5L X60 and X65 grades has increased in the last years. They are traditionally used up to now for applications on rigid risers for production and exportation and line pipes for oil and gas. In the case of seamless pipes, the great challenge is to fulfill the requirements of mechanical properties for X70 and X80 grades, quenched and tempered, with values of carbon equivalent low enough to assure a good weldability. This paper presents the results obtained by Vallourec and Mannesmann Tubes - V and M do Brazil on producing seamless pipes of X70 and X80 API grades, with outside diameter lower than 8 5/8{sup (} 219,1 mm ) and wall thickness up to 0,562{sup (} 14,3 mm ). Results of tensile, Charpy notch impact resistance and hardness tests are shown. Hydrogen-Induced and Environmental Cracking tests were also carried out, since for some applications is required a good resistance to these kinds of embrittlement mechanisms. The mechanical properties, microstructure and physical characteristics of welded joints were also evaluated. The results obtained up to now are quite promising, showing good suitability to the aimed final applications. (author)

  13. Microstructures and properties of low-alloy fire resistant steel

    Indian Academy of Sciences (India)

    Bimal Kumar Panigrahi

    2006-02-01

    Microstructures and properties of weldable quality low-alloy fire resistant structural steels (YS: 287–415 MPa) and TMT rebar (YS: 624 MPa) have been investigated. The study showed that it is possible to obtain two-thirds of room temperature yield stress at 600°C with 0.20–0.25% Mo and 0.30–0.55% Cr in low carbon hot rolled structural steel. Microalloying the Cr–Mo steel by niobium or vanadium singly or in combination resulted in higher guaranteed elevated temperature yield stress (250–280 MPa). The final rolling temperature should be maintained above austenite recrystallization stop temperature (∼ 900° C) to minimize dislocation hardening. In a quenched and self-tempered 600 MPa class TMT reinforcement bar steel (YS: 624 MPa), low chromium (0.55%) addition produced the requisite yield stress at 600°C. The low-alloy fire resistant steel will have superior thermal conductivity up to 600°C (> 30 W/m.k) compared to more concentrated alloys.

  14. Weld repair of helium degraded reactor vessel material

    Energy Technology Data Exchange (ETDEWEB)

    Kanne, W.R. Jr.; Lohmeier, D.A.; Louthan, M.R. Jr.; Rankin, D.T.; Franco-Ferreira, E.A. (Westinghouse Savannah River Co., Aiken, SC (United States)); Bruck, G.J.; Madeyski, A.; Shogan, R.P.; Lessmann, G.G. (Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center)

    1990-01-01

    Welding methods for modification or repair of irradiated nuclear reactor vessels are being evaluated at the Savannah River Site. A low-penetration weld overlay technique has been developed to minimize the adverse effects of irradiation induced helium on the weldability of metals and alloys. This technique was successfully applied to Type 304 stainless steel test plates that contained 3 to 220 appm helium from tritium decay. Conventional welding practices caused significant cracking and degradation in the test plates. Optical microscopy of weld surfaces and cross sections showed that large surface toe cracks formed around conventional welds in the test plates but did not form around overlay welds. Scattered incipient underbead cracks (grain boundary separations) were associated with both conventional and overlay test welds. Tensile and bend tests were used to assess the effect of base metal helium content on the mechanical integrity of the low-penetration overlay welds. The axis of tensile specimens was perpendicular to the weld-base metal interface. Tensile specimens were machined after studs were resistance welded to overlay surfaces.

  15. Weld repair of helium degraded reactor vessel material

    Energy Technology Data Exchange (ETDEWEB)

    Kanne, W.R. Jr.; Lohmeier, D.A.; Louthan, M.R. Jr.; Rankin, D.T.; Franco-Ferreira, E.A. [Westinghouse Savannah River Co., Aiken, SC (United States); Bruck, G.J.; Madeyski, A.; Shogan, R.P.; Lessmann, G.G. [Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center

    1990-12-31

    Welding methods for modification or repair of irradiated nuclear reactor vessels are being evaluated at the Savannah River Site. A low-penetration weld overlay technique has been developed to minimize the adverse effects of irradiation induced helium on the weldability of metals and alloys. This technique was successfully applied to Type 304 stainless steel test plates that contained 3 to 220 appm helium from tritium decay. Conventional welding practices caused significant cracking and degradation in the test plates. Optical microscopy of weld surfaces and cross sections showed that large surface toe cracks formed around conventional welds in the test plates but did not form around overlay welds. Scattered incipient underbead cracks (grain boundary separations) were associated with both conventional and overlay test welds. Tensile and bend tests were used to assess the effect of base metal helium content on the mechanical integrity of the low-penetration overlay welds. The axis of tensile specimens was perpendicular to the weld-base metal interface. Tensile specimens were machined after studs were resistance welded to overlay surfaces.

  16. Durable anti-fogging effect and adhesion improvement on polymer surfaces

    Science.gov (United States)

    Moser, E. M.; Gilliéron, D.; Henrion, G.

    2010-01-01

    The hydrophobic properties of polymeric surfaces may cause fogging in transparent packaging and poor adhesion to printing colours and coatings. Novel plasma processes for durable functionalization of polypropylene and polyethylene terephthalate substrates were developed and analysed using optical emission spectroscopy. A worm-like nano pattern was created on the polypropylene surface prior to the deposition of thin polar plasma polymerised layers. For both substrates, highly polar surfaces exhibiting a surface tension of up to 69 mN/m and a water contact angle of about 10° were produced - providing the anti-fogging effect. The deposition of thin plasma polymerised layers protects the increased surface areas and enables to tailoring the surface energy of the substrate in a wide range. Wetting characteristics were determined by dynamic contact angle measurements. Investigations of the chemical composition of several layers using X-ray photoelectron spectroscopy and FT-infrared spectroscopy were correlated with functional testing. The surface topography was investigated using atomic force microscopy. The weldability and peeling-off characteristics of the plasma treated polymer films could be adjusted by varying the process parameters. Global and specific migration analyses were undertaken in order to ensure the manufacturing of plasma treated polymer surfaces for direct food contact purposes.

  17. Change of Hot Cracking Susceptibility in Welding of High Strength Aluminum Alloy AA 7075

    Science.gov (United States)

    Holzer, M.; Hofmann, K.; Mann, V.; Hugger, F.; Roth, S.; Schmidt, M.

    High strength aluminum alloys are known as hard to weld alloys due to their high hot crack susceptibility. However, they have high potential for applications in light weight constructions of automotive industry and therefore it is needed to increase weldability. One major issue is the high hot cracking susceptibility. Vaporization during laser beam welding leads to a change of concentration of the volatile elements magnesium and zinc. Hence, solidification range of the weld and therefore hot cracking susceptibility changes. Additionally, different welding velocities lead to changed solidification conditions with certain influence on hot cracking. This paper discusses the influence of energy per unit length during laser beam welding of AA 7075 on the change of element concentration in the weld seam and the resulting influence on hot cracking susceptibility. Therefore EDS-measurements of weld seams generated with different velocities are performed to determine the change of element concentration. These quantitative data is used to numerically calculate the solidification range in order to evaluate its influence on the hot cracking susceptibility. Besides that, relative hot crack length and mechanical properties are measured. The results increase knowledge about welding of high strength aluminum alloy AA 7075 and hence support further developing of the welding process.

  18. Soldadura de aleaciones de aluminio con láseres de Nd:YAG de alta potencia

    Directory of Open Access Journals (Sweden)

    García Orza, J. A.

    1998-04-01

    Full Text Available Aluminium alloys have good mechanical properties (high strength-to-weight ratio, corrosion resistance and good workability. Their applications are growing up, specially in the transportation industry. Weldability is however poorer than in other materials; recent advances in high power YAG lasers are the key to obtain good appearance welds and higher penetration, at industrial production rates. Results of the combination of high power YAG beams with small fiber diameters and specific filler wires are presented. It is also characterized the airborne particulated material, by-product of the laser process: emission rates, size distribution and chemical composition are given for several aluminium alloys.

    El uso del Al y sus aleaciones es creciente en la fabricación de vehículos de transporte. Su soldabilidad es menor que la de otros materiales y las aleaciones presentan cierta disminución de propiedades por pérdida de aleantes y/o de su tratamiento térmico. Se revisa brevemente el uso de láseres de Nd:YAG de potencia en soldeo de aleaciones de aluminio y se presentan resultados de la combinación de haces de potencia guiados por fibras de pequeño diámetro, con focos ligeramente superpuestos en la pieza. Finalmente, se caracterizan los humos producidos en la soldadura con láser continuo de 2 kW.

  19. Aeronautical requirements for Inconel 718 alloy

    Science.gov (United States)

    Elefterie, C. F.; Guragata, C.; Bran, D.; Ghiban, B.

    2017-06-01

    The project goal is to present the requirements imposed by aviation components made from super alloys based on Nickel. A significant portion of fasteners, locking lugs, blade retainers and inserts are manufactured from Alloy 718. The thesis describes environmental factors (corrosion), conditions of external aggression (salt air, intense heat, heavy industrial pollution, high condensation, high pressure), mechanical characteristics (tensile strength, yield strength and fatigue resistance) and loadings (tensions, compression loads) that must be satisfied simultaneously by Ni-based super alloy, compared to other classes of aviation alloys (as egg. Titanium alloys, Aluminum alloys). For this alloy the requirements are strength durability, damage tolerance, fail safety and so on. The corrosion can be an issue, but the fatigue under high-magnitude cyclic tensile loading it’s what limits the lifetime of the airframe. Also, the excellent malleability and weldability characteristics of the 718 system make the material physical properties tolerant of manufacturing processes. These characteristics additionally continue to provide new opportunities for advanced manufacturing methods.

  20. The Effect of Thermo-mechanical Treatment of Substrate Preparation and Carburizing Temperature on The Morphology and Hardness of Carburizing on Low Carbon Steel

    Science.gov (United States)

    Dadan Ramdan, Raden; Adetia, Andra; Suratman, Rochim

    2017-07-01

    Low carbon steel has a lot of applications in daily life because of its excellent properties. Among its excellent properties are good ductility, toughness, formability, and weldability. For the case of application that requires good wear resistant, carbon steel is not sufficient. For this case it is required to increase the hardness of carbon steel, such as by carburizing method. In this method one factor that affects the carburizing layer is metal substrate condition, i.e grain size. Another factor is temperature that could have significant role on the carburized layer characteristics. Therefore the present works focus in the correlation between degree of reduction of cold rolling and carburizing temperature on the carburized layer characteristic. Thermo-mechanical treatment was applied to the specimen with reduction of 0%, 30%, and 80% by mean of rolling before carburizing process. Carburizing processes were carried out at temperature of 850°C, 900°C, and 950°C. Examinations on carburized specimens were conducted by metallography and micro hardness test. The result showed that the specimen of 80% reduction giving the thickest layer and the hardest surface layer. In addition, at temperature of 900°C, the hardest layer was formed with the hardness at 1003 HV. However, the thickest layer was formed at the temperature of 950°C.

  1. Microstructural response to heat affected zone cracking of prewelding heat-treated Inconel 939 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, M.A., E-mail: mgonzalez@comimsa.com.mx [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Martinez, D.I., E-mail: dorairma@yahoo.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Perez, A., E-mail: betinperez@hotmail.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Guajardo, H., E-mail: hguajardo@frisa.com [FRISA Aerospace, S.A. de C.V., Valentin G. Rivero No. 200, Col. Los Trevino, C.P. 66150, Santa Caterina N.L. (Mexico); Garza, A., E-mail: agarza@comimsa.com [Corporacion Mexicana de Investigacion en Materiales S.A. de C.V. (COMIMSA), Ciencia y Tecnologia No.790, Saltillo 400, C.P. 25295 Saltillo Coah. (Mexico)

    2011-12-15

    The microstructural response to cracking in the heat-affected zone (HAZ) of a nickel-based IN 939 superalloy after prewelding heat treatments (PWHT) was investigated. The PWHT specimens showed two different microstructures: 1) spherical ordered {gamma} Prime precipitates (357-442 nm), with blocky MC and discreet M{sub 23}C{sub 6} carbides dispersed within the coarse dendrites and in the interdendritic regions; and 2) ordered {gamma} Prime precipitates in 'ogdoadically' diced cube shapes and coarse MC carbides within the dendrites and in the interdendritic regions. After being tungsten inert gas welded (TIG) applying low heat input, welding speed and using a more ductile filler alloy, specimens with microstructures consisting of spherical {gamma} Prime precipitate particles and dispersed discreet MC carbides along the grain boundaries, displayed a considerably improved weldability due to a strong reduction of the intergranular HAZ cracking associated with the liquation microfissuring phenomena. - Highlights: Black-Right-Pointing-Pointer Homogeneous microstructures of {gamma} Prime spheroids and discreet MC carbides of Ni base superalloys through preweld heat treatments. Black-Right-Pointing-Pointer {gamma} Prime spheroids and discreet MC carbides reduce the intergranular HAZ liquation and microfissuring of Nickel base superalloys. Black-Right-Pointing-Pointer Microstructure {gamma} Prime spheroids and discreet blocky type MC carbides, capable to relax the stress generated during weld cooling. Black-Right-Pointing-Pointer Low welding heat input welding speeds and ductile filler alloys reduce the HAZ cracking susceptibility.

  2. Crossed-Wire Laser Microwelding of Pt-10 Pct Ir to 316 LVM Stainless Steel: Part II. Effect of Orientation on Joining Mechanism

    Science.gov (United States)

    Huang, Y. D.; Pequegnat, A.; Zou, G. S.; Feng, J. C.; Khan, M. I.; Zhou, Y.

    2012-04-01

    With the increasing complexity of medical devices and with efforts to reduce manufacturing costs, challenges arise in joining dissimilar materials. In this study, the laser weldability of dissimilar joints between Pt-10 pct Ir and 316 low-carbon vacuum melted (LVM) stainless steel (SS) crossed wires was investigated by characterizing the weld geometry, joint strength, morphology of weld cross sections, and differences in joining behavior, depending on which material is subject to the incident laser beam. With the Pt-Ir alloy on top, a significant amount of porosity was observed on the surface of the welds as well as throughout the weld cross sections. This unique form of porosity is believed to be a result of preferential vaporization of 316 LVM SS alloying elements that become mixed with the molten Pt-10 pct Ir during welding. The joining mechanism documented in micrographs of cross-sectioned welds was found to transition from laser brazing to fusion welding. It is inferred that the orientation of the two dissimilar metals ( i.e., which material is subject to the incident laser beam) plays an important role in weld quality of crossed-wire laser welds.

  3. Prospective high strength steel utilizing TRIP effect; Hentai yuki sosei koka wo riyoshita jisedai kokyodo usukoban

    Energy Technology Data Exchange (ETDEWEB)

    Sakuma, Y.; Kimura, N.; Itami, a.; Hiwatashi, S.; Kawano, O.; Sakata, K. [Nippon Steel Corp., Tokyo (Japan)

    1994-11-29

    The transformation induced plasticity (TRIP) means the large extension of chemically unstable austenitic {gamma} phase when it is transformed into martensite by the addition of dynamic energy. The application of TRIP effect is promising to the auto-body use steel plate because thin stainless steel plates excelling in bulging properties are producible. The present paper explained the enlarging mechanism of elongation, principle of production, examples of production on the actual line, formability, weldability and fatigue durability. Than that of the different conventional steel plates, a better combination of both strength and elongation was recorded through the actual line trial production of cold and hot rolled steel plates which were 590 to 980N/mm{sup 2} in tensile strength. Their apparent superiority in bulging properties was confirmed in the vicinity of plain strain, while their deep drawability was also known to be good through a TZP test. The presently developed steel excelled the conventional high-strength steel in strength at spot welding, while its fatigue strength was higher even than that of the dual-phase steel so far regarded as the best in it. 13 refs., 12 figs., 4 tabs.

  4. Al-Li alloy AA2198's very high cycle fatigue crack initiation mechanism and its fatigue thermal effect

    Science.gov (United States)

    Xu, Luopeng; Cao, Xiaojian; Chen, Yu; Wang, Qingyuan

    2015-10-01

    AA2198 alloy is one of the third generation Al-Li alloys which have low density, high elastic modulus, high specific strength and specific stiffness. Compared With the previous two generation Al-Li alloys, the third generation alloys have much improved in alloys strength, corrosion resistance and weldable characteristic. For these advantages, the third generation Al-Li alloys are used as aircraft structures, such as C919 aviation airplane manufactured by China and Russia next generation aviation airplane--MS-21. As we know, the aircraft structures are usually subjected to more than 108 cycles fatigue life during 20-30 years of service, however, there is few reported paper about the third generation Al-Li alloys' very high cycle fatigue(VHCF) which is more than 108 cycles fatigue. The VHCF experiment of AA2198 have been carried out. The two different initiation mechanisms of fatigue fracture have been found in VHCF. The cracks can initiate from the interior of the testing material with lower stress amplitude and more than 108 cycles fatigue life, or from the surface or subsurface of material which is the dominant reason of fatigue failures. During the experiment, the infrared technology is used to monitor the VHCF thermal effect. With the increase of the stress, the temperature of sample is also rising up, increasing about 15 °C for every 10Mpa. The theoretical thermal analysis is also carried out.

  5. High-strength iron aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    McKamey, C.G.; Marrero-Santos, Y.; Maziasz, P.J.

    1995-06-01

    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile density due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications, despite their excellent corrosion properties. Improvements in room temperature tensile ductility have been realized mainly through alloying effects, changes in thermomechanical processing to control microstructure, and by control of the specimen`s surface condition. Ductilities of 10-20% and tensile yield strengths as high as 500 MPa have been reported. In terms of creep-rupture strength, small additions of Mo, Nb, and Zr have produced significant improvements, but at the expense of weldability and room-temperature tensile ductility. Recently an alloy containing these additions, designated FA-180, was shown to exhibit a creep-rupture life of over 2000 h after a heat treatment of 1 h at 1150{degrees}C. This study presents the results of creep-rupture tests at various test temperatures and stresses and discusses the results as part of our effort to understand the strengthening mechanisms involved with heat treatment at 1150{degrees}C.

  6. Effect of chromium and carbon contents in cast iron on bonded microstructure of copper brazed high chromium cast iron and mild steel. Braze ho ni yoru kokuromu chutetsu to ko hagane no setsugo soshiki ni oyobosu chutetsuchu kuromu oyobi tansoryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sasaguri, N.; Matsubara, Y. (Kurume College of Technology, Fukuoka (Japan)); Ogi, K. (Kyushu University, Fukuoka (Japan))

    1993-08-25

    For the purpose of enhancing toughness, workability and weldability of high chromium castiron, hypoeutectic, eutectic and hypereutectic high chromium cast irons containing 10 to 30mass% Cr and mild steel were bonded by the brazing method using pure copper filler. This paper describes the effect of chromium and carbon contents in cast iron on the microstructural variations and behaviors of alloying elements in the bonded zone. The length of rod-like crystal precipitated at the cast iron-copper interface and the width of bonded zone decreased with an increase in Cr/C value of cast iron. It was considered that this is because diffusion of iron from steel to cast iron becomes less due to the decrease of difference in chemical potential of iron between the cast iron and the steel sides. Furthermore, alloy phase was composed of Fe, Cr, Cu and C, and the iron concentration in the alloy phase decreased and the chromium concentration increased with increasing the Cr/C value. The copper concentration was almost constant independent of the Cr/C value. It was suggested that the growth of alloy phase occurs under the diffusion control. 9 refs., 10 figs., 1 tab.

  7. Effects of Process Conditions on the Mechanical Behavior of Aluminium Wrought Alloy EN AW-2219 (AlCu6Mn Additively Manufactured by Laser Beam Melting in Powder Bed

    Directory of Open Access Journals (Sweden)

    Michael Cornelius Hermann Karg

    2017-01-01

    Full Text Available Additive manufacturing is especially suitable for complex-shaped 3D parts with integrated and optimized functionality realized by filigree geometries. Such designs benefit from low safety factors in mechanical layout. This demands ductile materials that reduce stress peaks by predictable plastic deformation instead of failure. Al–Cu wrought alloys are established materials meeting this requirement. Additionally, they provide high specific strengths. As the designation “Wrought Alloys” implies, they are intended for manufacturing by hot or cold working. When cast or welded, they are prone to solidification cracks. Al–Si fillers can alleviate this, but impair ductility. Being closely related to welding, Laser Beam Melting in Powder Bed (LBM of Al–Cu wrought alloys like EN AW-2219 can be considered challenging. In LBM of aluminium alloys, only easily-weldable Al–Si casting alloys have succeeded commercially today. This article discusses the influences of boundary conditions during LBM of EN AW-2219 on sample porosity and tensile test results, supported by metallographic microsections and fractography. Load direction was varied relative to LBM build-up direction. T6 heat treatment was applied to half of the samples. Pronounced anisotropy was observed. Remarkably, elongation at break of T6 specimens loaded along the build-up direction exceeded the values from literature for conventionally manufactured EN AW-2219 by a factor of two.

  8. Microstructure stability: Optimisation of 263 Ni-based superalloy

    Directory of Open Access Journals (Sweden)

    Crozet Coraline

    2014-01-01

    Full Text Available To reduce CO2 emissions on coal-fired power plant, A-ultra supercritical (A-USC power plant whose steam conditions exceed 700 °C are being developed. At these elevated temperatures, the use of Ni-base superalloys becomes necessary. In this context and within the European project NextGenPower, focus is made on commercial Nimonic C-263 as a candidate material for turbine rotors. Nimonic C-263 is known to have low sensitivity to segregation, high workability and high weldability which are major properties for the manufacture of large shafts. Long-term creep strength is also required for this application and unfortunately Nimonic C-263 shows η-phase precipitation after long-time exposure between 700 °C–900 °C which is detrimental for long-term creep properties. The composition of Nimonic C-263 was thus optimised to overcome the formation of η-phase. Trial tests were made in order to study the effect of hardening contribution elements on microstructural and mechanical properties. Then, a 500 mm diameter forged rotor was made from optimised 263 alloy and shows promising properties.

  9. Laser Encapsulation of Organic Electronics with Adapted Diode Lasers in Flexible Production Processes

    Science.gov (United States)

    Brosda, Maximilian; Olowinsky, Alexander; Pelzer, Alexander

    Flexible organic electronics such as OLPV and OLED modules are highly sensitive against water and oxygen. To protect them against the environment and to ensure a long lifetime visual transparent ultra high barrier films are used for the encapsulation process. These multilayer films usually consist of a polymer substrate on which, depending on the requirements, various functional layers are applied. The organic device is then fully packed in this films. Instead of conventional joining these film with adhesive, a flexible laser based process can be an interesting alternative especially for roll2roll applications. According to a precise spectral analysis and a consideration of the interaction between the laser radiation and the individual layers of the film a suitable laser beam source is selected. With this laser beam source the weldability of the films is investigated. For analysis of the weldseam and the melted volume cross sections and scanning-electron-microscopy-images are prepared. The strength of the weld is determined by T-Peel tensile tests.

  10. NASA's Advanced solid rocket motor

    Science.gov (United States)

    Mitchell, Royce E.

    The Advanced Solid Rocket Motor (ASRM) will not only bring increased safety, reliability and performance for the Space Shuttle Booster, it will enhance overall Shuttle safety by effectively eliminating 174 failure points in the Space Shuttle Main Engine throttling system and by reducing the exposure time to aborts due to main engine loss or shutdown. In some missions, the vulnerability time to Return-to-Launch Site aborts is halved. The ASRM uses case joints which will close or remain static under the effects of motor ignition and pressurization. The case itself is constructed of the weldable steel alloy HP 9-4-0.30, having very high strength and with superior fracture toughness and stress corrosion resistance. The internal insulation is strip-wound and is free of asbestos. The nozzle employs light weight ablative parts and is some 5,000 pounds lighter than the Shuttle motor used to date. The payload performance of the ASRM-powered Shuttle is 12,000 pounds higher than that provided by the present motor. This is of particular benefit for payloads delivered to higher inclinations and/or altitudes. The ASRM facility uses state-of-the-art manufacturing techniques, including continuous propellant mixing and direct casting.

  11. Development of Fine-Grained, Low-Carbon Bainitic Steels with High Strength and Toughness Produced Through the Conventional Hot-Rolling and Air-Cooling

    Science.gov (United States)

    Dhua, Sanjay Kumar; Sarkar, Partha Pratim; Saxena, Atul; Jha, Bimal Kumar

    2016-09-01

    Low-carbon bainitic steels have created enormous interest among scientists across the world in the past few decades because of their high strength, toughness, and weldability replacing the conventional quenched and tempered medium-carbon steels. Three experimental steels with varying alloy additions were made in a 100-kg laboratory induction furnace and cast into 100-mm-diameter cylindrical ingots. These ingots were hot-rolled and air-cooled to 6-mm plates in an experimental rolling mill with selected thermomechanical parameters. Steels processed through this process provided an ultrafine low-carbon bainitic microstructure with maximum yield strength (YS) and ultimate tensile strength (UTS) 575 and 705 MPa, respectively. The Charpy impact toughness of the experimental steels was excellent, and at 253 K (-20 °C), it varied from 114 to 170 Joules. Cu-B-added steel was found to give an optimum combination of strength, YS-575 MPa, and toughness, 114 J at 253 K (-20 °C). Thus, fine-grained, low-carbon bainitic steels could be developed with a proper combination of alloying elements and thermomechanical parameters even by air-cooling.

  12. Thermomechanically-controlled Processing for Producing Ship-building Steels

    Directory of Open Access Journals (Sweden)

    B. Basu

    2005-01-01

    Full Text Available The thermomechanically-controlled processing of a newly developed high-strength lowalloy steel has been designed in such a way that the problems, normally faced in producing thequench and tempered steels, have been mitigated and the final product (steel plates are available in as rolled condition rather than quench and tempered steels.A low-carbon, low-alloy steel having nickel, chromium, copper, niobium, boron, has been designed for ease of welding, improved weldability over the conventional steels, and responsiveto the thermomechanically-controlled processing. A number of laboratory-scale batches of the alloy were made with different combinations of thermomechanically-controlled processingparameters. The different thermomechanically-controlled processing parameters studied include (i slab-reheating temperature,~ (ii. def.orm ation above recrvstallisation temperature, (iiideformation below recrystallisation temperature, and (iv finish-rolling temperature. The thermomechanically-processed steel plates, under certain combinations of  thermomechanically-controlled ~rocessi-ne.o arameters. showed excellent combination of imvact and tensile n.r on. erties. In this paper, the microstructure-property correlation has been made to throw light on the type of microstructure required to obtain such superior package of mechanical properties. Further, the optimised laboratory-scale thermomechanically-controlled processing parameters, which were used to process newer hatches of the steel made through industrial route, have delivered encouraging results.

  13. Influence of Al on the microstructure and carburization performance of a Ni-based alloy coating

    Energy Technology Data Exchange (ETDEWEB)

    Cangue, Feliciano Jose Ricardo, E-mail: fcangue@yahoo.com [Federal University of Parana, Centro Politecnico, s/n - Bairro Jardim das Americas, Curitiba, Parana, Cx P. 19011, CEP: 81531-990 (Brazil); D' Oliveira, Ana Sofia Climaco Monteiro, E-mail: sofmat@ufpr.br [Mechanical Engineering Department, Federal University of Parana, Centro Politecnico, s/n - Bairro Jardim das Americas, Curitiba, Parana, Cx P. 19011, CEP: 81531-990 (Brazil)

    2010-04-15

    Carburization is a degradation mechanism involving the diffusion of carbon into a metal alloy and its accumulation on the surface. Coke forms on the internal walls of crude oil refining equipment and adversely affects its efficiency and service life. In an attempt to enhance the service life of materials exposed to these aggressive environments, this work investigated the development of a protective coating to reduce the diffusion of carbon into the surfaces of components. Coatings were tailored by mixing the atomized Ni alloy (Hastealloy C) with 5 wt% and 15 wt% Al powders and deposited by Plasma Transferred Arc hardfacing. Pack carburizing was carried out at 650 deg. C and 850 deg. C for 6 h, and temperature stability was tested in an air furnace to evaluate the performance of the coatings. Characterization included measurement of Vickers microhardness profiles and microstructure analysis by optical and scanning electron microscopy and X-ray diffraction. The good weldability of the original Ni-based alloy was not altered by the presence of Al. Richer Al coatings developed ordered aluminide compounds in a Ni matrix and exhibited increased hardness and dilution. Exposure to temperatures of 650 deg. C and 850 deg. C in an air furnace and to a carburizing environment neither compromised coating hardness nor produced a carburizing layer, although carbides were identified at the top surface. Our results will be of benefit in the development of an alternative solution for the protection of components operating in carburizing environments.

  14. Replacement of Cobalt base alloys hardfacing by NOREM alloy; EDF experience and development, some metallurgical considerations. Valves application (CLAMA, RAMA)

    Energy Technology Data Exchange (ETDEWEB)

    Carnus, M. [EDF DPN UTO Direction Expertise Technique, Noisy le Grand (France); Confort, X. [VELAN SAS, Lyon (France)

    2011-07-01

    Cobalt base alloys, such as Stellite 6 and 21, are used extensively in applications where superior resistance to wear and corrosion are required. However the use of Cobalt alloys hardfacing materials, especially on valves, is a major contributor to the level of radioactive contamination of nuclear facilities. NOREM alloys, an iron base and cobalt free materials, have been developed through an Electric Power Research Institute (EPRI) long running program during the eighties as an alternative of Stellite. This alloy has relatively good weldability properties, it was developed initially for repairing Stellite hardfacing (deposit over existing hardfacing alloys). This alloy has good corrosion resistance properties associated with elevated hardness (HRC 36-42). Technological properties (such as galling resistance, wear resistance) have been evaluated through different testing programs led by EPRI, AECL(Atomic Energy of Canada Limited), Valves manufacturers, EDF and others during the nineties. More recently EDF (for replacement of globe valves) has carried out testing program focused on weld deposit chemistry and mechanical properties. NOREM is a candidate for replacement of stellite hardfacing on valves. However this alloy is not so versatile as stellite alloys regarding technological properties (such as wear resistance) at elevated temperature and under high contact pressure. As a consequence some limits have to be considered for application on valves operating at elevated temperature and under high contact pressure (> 20 Mpa). Examples of application on valves, from VELAN manufacturer, for EDF PWR equipment are given. The industrial feedback from installed equipment (CLAMA, RAMA) since 2006 on EDF PWR has been good

  15. Microstructural evaluation of a low carbon steel submitted to boriding treatment pre and post GTAW welding; Avaliacao microestrutural de um aco de baixo carbono submetido ao tratamento de boretacao pre e pos-soldagem GTAW

    Energy Technology Data Exchange (ETDEWEB)

    Pollnow, Edilson Nunes; Osorio, Alice Goncalves, E-mail: edilson.pollnow@hotmail.com, E-mail: osorio.alice@gmail.com [Universidade Federal de Pelotas (CDTec/UFPel), Pelotas, RS (Brazil). Centro de Desenvolvimento Tecnologico; Araujo, Douglas Bezerra de, E-mail: dbaraujo@ufu.br [Universidade Federal de Uberlandia (FEMEC/UFU), Uberlandia, MG (Brazil). Faculdade de Engenharia Mecanica; Passos, Thais Andrezza dos; Souza, Daniel, E-mail: thais.andrezza.passos@gmail.com, E-mail: danielsouza@furg.br [Universidade Federal do Rio Grande (EE/FURG), Rio Grande, RS (Brazil). Escola de Engenharia

    2017-04-15

    Studies on surface engineering area are given great importance due to the improvement that surface modifications provide to materials. With a global market that has the need to provide parts and equipment with extended service life and low cost, to support stringent requests and thus maintain its high performance, surface treatments may bring what was impossible into reality. Among the surface treatments that have received attention recently, we have the thermochemical process of boriding. The boriding process consists of saturate the surface of steels and metal alloys with boron. This saturation provides an increase in the surface properties not inherent to the base metal, such as hardness, resistance to abrasion and corrosion. Although the properties of boriding steels have already been studied, the effects that the boriding process perform on the steel during or after the welding processes are not known. Hence, it is the purpose of this study to evaluate the microstructure of a low carbon steel treated with boriding before and after GTAW welding. The results indicated poor metallurgical weldability of low carbon steel with boride layer, with the presence of solidification cracks. Nonetheless, the steel welded previous to boring treatment presented a more ductile nucleus, with harder surface. Although the values of hardness within the nucleus of the steel had dropped drastically at the welded zone after the boring, the surface of this steel showed higher values of hardness due to the boriding layer. This fact should be considered when applications where wear resistance is needed. (author)

  16. Russian aluminum-lithium alloys for advanced reusable spacecraft

    Science.gov (United States)

    Charette, Ray O.; Leonard, Bruce G.; Bozich, William F.; Deamer, David A.

    1998-01-01

    Cryotanks that are cost-affordable, robust, fuel-compatible, and lighter weight than current aluminum design are needed to support next-generation launch system performance and operability goals. The Boeing (McDonnell Douglas Aerospace-MDA) and NASA's Delta Clipper-Experimental Program (DC-XA) flight demonstrator test bed vehicle provided the opportunity for technology transfer of Russia's extensive experience base with weight-efficient, highly weldable aluminum-lithium (Al-Li) alloys for cryogenic tank usage. As part of NASA's overall reusable launch vehicle (RLV) program to help provide technology and operations data for use in advanced RLVs, MDA contracted with the Russian Academy of Sciences (RAS/IMASH) for design, test, and delivery of 1460 Al-Li alloy liquid oxygen (LO2) cryotanks: one for development, one for ground tests, and one for DC-XA flight tests. This paper describes the development of Al-Li 1460 alloy for reusable LO2 tanks, including alloy composition tailoring, mechanical properties database, forming, welding, chemical milling, dissimilar metal joining, corrosion protection, completed tanks proof, and qualification testing. Mechanical properties of the parent and welded materials exceeded expectations, particularly the fracture toughness, which promise excellent reuse potential. The LO2 cryotank was successfully demonstrated in DC-XA flight tests.

  17. The effect of fabrication on corrosion in aluminum 2195: Environmental and microstructural considerations

    Science.gov (United States)

    Walsh, Daniel W.

    1994-01-01

    Aluminum alloys containing lithium are particularly attractive to the aerospace structural designer. Lithium's density is only 0.53 g/cc, thus an addition of one weight percent lithium not only increases yield strength, but decreases the density by almost three percent while increasing the modulus by over six percent. The fact that lithium improves these physical properties simultaneously has led to intense study and development of the alloy system. Heretofore, problems in large scale alloy production have retarded commercial development. During the last fifteen years, advances in production technology have rekindled interest in Al-Li alloys, and aluminum suppliers have developed many candidate aerospace materials. However, if these alloys are to be employed successfully, a more complete understanding of their nonequilibrium metallurgy is required. Peel and Starke have each pointed out that an understanding of the weldability of these alloys is a critical step in their implementation. This study addresses the critical lack of information on the environmental compatibility of welded Al 2195 components. Corrosion data for these systems is incomplete, particularly for welded materials exposed to sea water or sea water condensate.

  18. Abrasive-assisted Nickel Electroforming Process with Moving Cathode

    Science.gov (United States)

    REN, Jianhua; ZHU, Zengwei; XIA, Chunqiu; QU, Ningsong; ZHU, Di

    2017-03-01

    In traditional electroforming process for revolving parts with complex profiles, the drawbacks on surface of deposits, such as pinholes and nodules, will lead to varying physical and mechanical properties on different parts of electroformed components. To solve the problem, compositely moving cathode is employed in abrasive-assisted electroforming of revolving parts with complicated profiles. The cathode translates and rotates simultaneously to achieve uniform friction effect on deposits without drawbacks. The influences of current density and translation speed on the microstructure and properties of the electroformed nickel layers are investigated. It is found that abrasive-assisted electroforming with compound cathode motion can effectively remove the pinholes and nodules, positively affect the crystal nucleation, and refine the grains of layer. The increase of current density will lead to coarse microstructure and lower micro hardness, from 325 HV down to 189 HV. While, faster translational linear speed produces better surface quality and higher micro hardness, from 236 HV up to 283 HV. The weld-ability of the electroformed layers are also studied through the metallurgical analysis of welded joints between nickel layer and 304 stainless steel. The electrodeposited nickel layer shows fine performance in welding. The novel compound motion of cathode promotes the mechanical properties and refines the microstructure of deposited layer.

  19. Abrasive-assisted Nickel Electroforming Process with Moving Cathode

    Science.gov (United States)

    REN, Jianhua; ZHU, Zengwei; XIA, Chunqiu; QU, Ningsong; ZHU, Di

    2017-03-01

    In traditional electroforming process for revolving parts with complex profiles, the drawbacks on surface of deposits, such as pinholes and nodules, will lead to varying physical and mechanical properties on different parts of electroformed components. To solve the problem, compositely moving cathode is employed in abrasive-assisted electroforming of revolving parts with complicated profiles. The cathode translates and rotates simultaneously to achieve uniform friction effect on deposits without drawbacks. The influences of current density and translation speed on the microstructure and properties of the electroformed nickel layers are investigated. It is found that abrasive-assisted electroforming with compound cathode motion can effectively remove the pinholes and nodules, positively affect the crystal nucleation, and refine the grains of layer. The increase of current density will lead to coarse microstructure and lower micro hardness, from 325 HV down to 189 HV. While, faster translational linear speed produces better surface quality and higher micro hardness, from 236 HV up to 283 HV. The weld-ability of the electroformed layers are also studied through the metallurgical analysis of welded joints between nickel layer and 304 stainless steel. The electrodeposited nickel layer shows fine performance in welding. The novel compound motion of cathode promotes the mechanical properties and refines the microstructure of deposited layer.

  20. Development of a rotor alloy for advanced ultra super critical turbine power generation system

    Energy Technology Data Exchange (ETDEWEB)

    Miyashita, Shigekazu; Yamada, Masayuki; Suga, Takeo; Imai, Kiyoshi; Nemoto, Kuniyoshi; Yoshioka, Youmei [Toshiba Corporation, Yokohama (Japan)

    2008-07-01

    A Ni-based superalloy ''TOS1X'', for the rotor material of the 700 class advanced ultra super critical (A-USC) turbine power generation system was developed. TOS1X is an alloy that is improved in the creep rupture strength of Inconel trademark 617 maintaining both forgeability and weldability. The 7 t weight model rotor made of TOS1X was manufactured by double melt process, vacuum induction melting and electro slag remelting, and forging. During forging process, forging cracks and any other abnormalities were not detected on the ingots. The metallurgical and the mechanical properties in this rotor were investigated. Macro and micro structure observation, and some mechanical tests were conducted. According to the metallurgical structure investigation, there was no remarkable segregation in whole area and the forging effect was reached in the center part of the rotor ingot. The results of tensile test and creep rupture test proved that proof stress and tensile stress of the TOS1X are higher than those of Inconel trademark 617 and creep rupture strength of TOS1X is much superior than that of Inconel trademark 617. (orig.)

  1. Evaluation of susceptibility of high strength steels to hydrogen delayed cracking

    Directory of Open Access Journals (Sweden)

    B. Świeczko-Żurek

    2006-08-01

    Full Text Available Purpose: Purpose of this paper is evaluation of susceptibility of high-strength structural steels to hydrogendelayed cracking.Design/methodology/approach: Susceptibility to hydrogen delayed cracking of high-strength alloy steels havebeen made under constant load in hydrogen generating environments. Test were carried out using round notchedspecimens subjected to axial tensile load being equivalence to 75-96% of maximum force obtained from atensile tests in air. Two constructional middle carbon steel – grades 26H2MF and 34HNM were tested in used(worn out mineral engine oil at temperature of 80°C. One low carbon weldable steel grade – 14HNMBCu wasinvestigated in sea-water under cathodic polarization at room temperature. Presence or lack of cracking within200 hours was chosen as a measure of susceptibility to hydrogen delayed cracking. Fracture modes of failedsamples were examined with the use of scanning electron microscope.Findings: All tested steels reveal high resistance to hydrogen degradation under constant load. Hydrogendelayed cracking does not occur until the load level is as high as flow stress (yield strength.Research limitations/implications: Further research should be taken to reveal the exact mechanism of crackinitiation.Practical implications: Tested steels could be safely utilized within elastic range of stress in hydrogengenerating environments.Originality/value: Under the critical load and hydrogen concentration notched samples premature failed andhydrogen-enhanced localised plasticity (HELP model is a viable degradation mechanism.

  2. Numerical modelling of thermal phenomenon in friction stir welding of aluminum plates

    Science.gov (United States)

    Vaira Vignesh, R.; Padmanaban, R.; Arivarasu, M.; Thirumalini, S.; Gokulachandran, J.; Sai Ram, Mutyala Sesha Satya

    2016-09-01

    Friction stir welding (FSW) is a solid state welding process with potential to join materials that are non weldable by conventional fusion welding techniques. The study of heat transfer in FSW aids in the identification of defects like flash, inadequate heat input, poor material flow and mixing etc. In this paper, transient temperature distribution during FSW of aluminum alloy AA6061-T6 was simulated using finite element modelling. The model was used to predict the peak temperature and analyse the thermal history during FSW. The effect of process parameters namely tool rotation speed, tool traverse speed (welding speed), shoulder diameter and pin diameter of tool on the temperature distribution was investigated using two level factorial design. The model results were validated using the experimental results from the published literature. It was found that peak temperature was directly proportional to tool rotation speed and shoulder diameter and inversely proportional to tool traverse speed. The effect of pin diameter on peak temperature was found to be trivial.

  3. A Study on Tooling and Its Effect on Heat Generation and Mechanical Properties of Welded Joints in Friction Stir Welding

    Science.gov (United States)

    Tikader, Sujoy; Biswas, Pankaj; Puri, Asit Baran

    2016-06-01

    Friction stir welding (FSW) has been the most attracting solid state welding process as it serves numerous advantages like good mechanical, metallurgical properties etc. Non weldable aluminium alloys like 5XXX, 7XXX series can be simply joined by this process. In this present study a mathematical model has been developed and experiments were successfully performed to evaluate mechanical properties of FSW on similar aluminium alloys i.e. AA1100 for different process parameters and mainly two kind of tool geometry (straight cylindrical and conical or cylindrical tapered shaped pin with flat shoulder). Tensile strength and micro hardness for different process parameters are reported of the welded plate sample. It was noticed that in FSW of similar alloy with tool made of SS-310 tool steel, friction is the major contributor for the heat generation. It was seen that tool geometry, tool rotational speed, plunging force by the tool and traverse speed have significant effect on tensile strength and hardness of friction stir welded joints.

  4. Havacılıkta Kullanılan 6013-T6 Alüminyum Alaşımının Sürtünme Karıştırma Kaynağıyla Birleştirilmesi

    Directory of Open Access Journals (Sweden)

    Haşim KAFALI

    2014-06-01

    Full Text Available Aluminum alloys are widely used in aircraft structures especially in the fuselage and wing fairings. For the joining of these structures, the traditional technique of riveting is used. However, riveting increases the structural weight of the aircraft and rivet holes cause stress concentration for the fatigue cracks. In traditional welding techniques, metal is heated up to the melting point for this reason the mechanical behavior of the material deteriorates. In recent years Friction Stir Welding (FSW has been used as an alternative joining technique. In this study; the weldability by FSW of 6013-T6, an aluminum alloy having an important place in aviation and space industries; the mechanical properties of the material after welding; and the changes in the internal structure have been examined. Along the course of this study, the raw material and the welded material have been tested by microhardness test and tensile test. The discontinuity and defect controls of the welded materials have been achieved by nondestructivetesting methods. And also the changes in the heat values have been observed and then results were interpreted

  5. Thermo-mechanical modelling of high temperature crack growth in electron beam welding of a CuCrZr alloy; Modelisation thermomecanique de la fissuration a chaud en soudage par faisceau d'electrons d'un alliage CuCrZr

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, J

    2009-03-15

    The aim of this research thesis is to find out which crack initiation criteria can be applied in the case of electron beam welding of CuCrZr alloy components. After a literature survey on the high temperature cracking phenomenon, the author describes its microscopic origins and presents the main high temperature crack growth criteria. He reports metallurgical, thermal and mechanical characterizations of the studied alloy performed by optical, scanning electronic and transmission electronic microscopy, crystallographic analysis, residual stress determination using the hole method, mechanical testing at room and high temperature (from room temperature to 1000 C), determination of solidification route and of thermal conductivity, and thermal expansion measurements. He describes electron beam weldability tests performed on the alloy. As these tests are performed on simple geometry samples, they allow the high temperature crack growth to be observed. These experiments are then modelled using two finite element codes, Castem and Calcosoft. Then, after a presentation of the main hypotheses used in these numerical models, the author applies the high temperature crack growth criteria. Results obtained for theses criteria are then analysed and discussed.

  6. Additive Manufacturing of IN100 Superalloy Through Scanning Laser Epitaxy for Turbine Engine Hot-Section Component Repair: Process Development, Modeling, Microstructural Characterization, and Process Control

    Science.gov (United States)

    Acharya, Ranadip; Das, Suman

    2015-09-01

    This article describes additive manufacturing (AM) of IN100, a high gamma-prime nickel-based superalloy, through scanning laser epitaxy (SLE), aimed at the creation of thick deposits onto like-chemistry substrates for enabling repair of turbine engine hot-section components. SLE is a metal powder bed-based laser AM technology developed for nickel-base superalloys with equiaxed, directionally solidified, and single-crystal microstructural morphologies. Here, we combine process modeling, statistical design-of-experiments (DoE), and microstructural characterization to demonstrate fully metallurgically bonded, crack-free and dense deposits exceeding 1000 μm of SLE-processed IN100 powder onto IN100 cast substrates produced in a single pass. A combined thermal-fluid flow-solidification model of the SLE process compliments DoE-based process development. A customized quantitative metallography technique analyzes digital cross-sectional micrographs and extracts various microstructural parameters, enabling process model validation and process parameter optimization. Microindentation measurements show an increase in the hardness by 10 pct in the deposit region compared to the cast substrate due to microstructural refinement. The results illustrate one of the very few successes reported for the crack-free deposition of IN100, a notoriously "non-weldable" hot-section alloy, thus establishing the potential of SLE as an AM method suitable for hot-section component repair and for future new-make components in high gamma-prime containing crack-prone nickel-based superalloys.

  7. Obtained and characterization of composite materials W-Cu for electrical contact; Obtencion y caracterizacion de materiales compuestos W-Cu para contactos electricos

    Energy Technology Data Exchange (ETDEWEB)

    Krivij, N.; Alfonso-Trujillo, E.; Garcia-Sanchez, L. L.; Villalonga, J. A.; Formoso-Prego, A.; Alguacil, E. J.; Corres-Sanchez, A.

    2003-07-01

    In the Cuban Metallurgical Research Center (CIME), are manufactured by powder metallurgy, shims of adjustment of a W-Cu composite material, that are used in the electrical contacts of the panels of control of the portico derricks that operate in the port of Havana City. The base material used has a composition of 70% in mass electrolytic copper powder and wolfram powder of (30%) that is obtained by reduction from the oxide from wolfram. The powders are submitted to the stages of mixed, pressed and agglomeration and is obtained a composite material with free particles of W occluded in a counterfoil of Cu matrix, that do not interact and they provide the following properties: high melting temperature, high electro and thermo conductivity and corrosion resistance, high mechanical and electrical strengtheners, decrease weldability and stability during their development. However, when not reacting the volframio particles with the copper, the compound material will begin to fuse to the temperature of the copper, on the other hand and for the same reason the resistance to the corrosion should be similar to that of the pure copper. The shims of adjustment are fixed to the bodies of high purity copper welding with a silver alloy, the one which provides the maximum qualities of the Cu, as elasticity, breaking strength, thermal and electrical conductivities, as well corrosion resistance. (Author) 36 refs.

  8. Deformation behavior of laser welds in high temperature oxidation resistant Fe-Cr-Al alloys for fuel cladding applications

    Science.gov (United States)

    Field, Kevin G.; Gussev, Maxim N.; Yamamoto, Yukinori; Snead, Lance L.

    2014-11-01

    Ferritic-structured Fe-Cr-Al alloys are being developed and show promise as oxidation resistant accident tolerant light water reactor fuel cladding. This study focuses on investigating the weldability and post-weld mechanical behavior of three model alloys in a range of Fe-(13-17.5)Cr-(3-4.4)Al (wt.%) with a minor addition of yttrium using modern laser-welding techniques. A detailed study on the mechanical performance of bead-on-plate welds using sub-sized, flat dog-bone tensile specimens and digital image correlation (DIC) has been carried out to determine the performance of welds as a function of alloy composition. Results indicated a reduction in the yield strength within the fusion zone compared to the base metal. Yield strength reduction was found to be primarily constrained to the fusion zone due to grain coarsening with a less severe reduction in the heat affected zone. For all proposed alloys, laser welding resulted in a defect free weld devoid of cracking or inclusions.

  9. Examination of mechanical properties of magnesium plates joined by friction stir welding

    Directory of Open Access Journals (Sweden)

    Aydın Şık

    2010-12-01

    Full Text Available The use of magnesium, which is the latest metal of our age, is increasing in parallel with the advances in industry and technology. Due to its lightness, durability and long life, its usage is increasing in the automotive and space-craft industries. As a result of the advances in magnesium use, there are innovations in welding methods as well. The desired mechanical properties can't be obtained after welding. While there are some difficulties in fusion welding of magnesium material and its alloys, some of them can't be joined by fusion welding at all. Weldability of a material is the property that plays an important role in enabling its wider use and determines the method of producing products out of this material. Magnesium plates were joined successfully by friction stir welding method. Welded joints are exposed to various mechanic stresses and especially to dynamic loads. Cracks are observed to occur due to dynamic loads. Plates were joined in butt position and the mechanical properties of the occurring joint are examined.

  10. Newly developed high performance structural steels for long span bridge construction; Chotaikyo ni shiyosareru shinkozai

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Y. [Nippon Steel Corp., Tokyo (Japan)

    1998-11-15

    This paper reports new steels for long span bridge construction with the thick steel plate as a main part. On the basis of the high-tension steel utilizing technology examined around 1965, a reheated, quenched-and-tempered martensitic steel plate (HT690) was used for the Onaruto Bridge and Seto Ohashi Bridge in a Honsyu-Shikoku linking project. Moreover, a larger number of quenched martensitic high-tension steel plates (HT670 and HT780) were used for the Yojima Bridge together with existing SM400, SM490, SM520, and SM570 steel plates. The lately built Akashi Kaikyo Ohashi Bridge that is 1990 m between struts is longest in the world. The newly developed steel plate (HT780) for a bridge girder of which weldability was improved for lightening was used actually. To reduce the welding cost or improve the welding environment, this steel plate decreased the preheating temperature for weld cracking prevention in a heat-affected zone from about 100degC to 50degC or less. A new wire (of 1800Mpa in tensile strength) was also used for a cable. In future, the bridge girder will be economically and rationally manufactured by the development of design and construction methods that fully draw the characteristics of the new steel. 33 refs., 9 figs., 2 tabs.

  11. Control of Microstructures and the Practical Properties of API X80 Grade Heavy-Wall High-Frequency Electric Resistance-Welded Pipe with Excellent Low-Temperature Toughness

    Science.gov (United States)

    Goto, Sota; Nakata, Hiroshi; Toyoda, Shunsuke; Okabe, Takatoshi; Inoue, Tomohiro

    2017-10-01

    This paper describes development of heavy-walled API X80 grade high-frequency electric resistance-welded (HFW) line pipes and conductor-casing pipes with wall thicknesses up to 20.6 mm. A fine bainitic-ferrite microstructure, which is preferable for low-temperature toughness, was obtained by optimizing the carbon content and applying the thermomechanical controlled hot-rolling process. As a result, the Charpy ductile-brittle transition temperature (DBTT) was well below 227 K (-46 °C) in the base metal of the HFW line pipe. When the controlled hot-rolling ratio (CR) was increased from 23 to 48 pct, the area average grain size decreased from 15 to 8 μm. The dependence of CTOD properties on CR was caused by the largest grain which is represented by the area average grain size. No texture development due to the increase of CR from 23 to 48 pct was observed. In addition, because controlled in-line heat treatment of the longitudinal weld seam also produced the fine bainitic-ferrite microstructure at the weld seam, DBTT was lower than 227 K (-46 °C) at the weld portion. The developed pipes showed good girth weldability without preheat treatment, and fracture in the tensile test initiated from the base metal in all cases.

  12. NASA's Advanced solid rocket motor

    Science.gov (United States)

    Mitchell, Royce E.

    1993-01-01

    The Advanced Solid Rocket Motor (ASRM) will not only bring increased safety, reliability and performance for the Space Shuttle Booster, it will enhance overall Shuttle safety by effectively eliminating 174 failure points in the Space Shuttle Main Engine throttling system and by reducing the exposure time to aborts due to main engine loss or shutdown. In some missions, the vulnerability time to Return-to-Launch Site aborts is halved. The ASRM uses case joints which will close or remain static under the effects of motor ignition and pressurization. The case itself is constructed of the weldable steel alloy HP 9-4-0.30, having very high strength and with superior fracture toughness and stress corrosion resistance. The internal insulation is strip-wound and is free of asbestos. The nozzle employs light weight ablative parts and is some 5,000 pounds lighter than the Shuttle motor used to date. The payload performance of the ASRM-powered Shuttle is 12,000 pounds higher than that provided by the present motor. This is of particular benefit for payloads delivered to higher inclinations and/or altitudes. The ASRM facility uses state-of-the-art manufacturing techniques, including continuous propellant mixing and direct casting.

  13. Investigation of Friction Stir Welding of Al Metal Matrix Composite Materials

    Science.gov (United States)

    Diwan, Ravinder M.

    2003-01-01

    The innovative process of Friction Stir Welding (FSW) has generated tremendous interest since its inception about a decade or so ago since the first patent in 1991 by TWI of Cambridge, England. This interest has been seen in many recent international conferences and publications on the subject and relevant published literature. Still the process needs both intensive basic study of deformation mechanisms during this FSW process and analysis and feasibility study to evaluate production methods that will yield high quality strong welds from the stirring action of the appropriate pin tool into the weld plate materials. Development of production processes is a complex task that involves effects of material thickness, materials weldability, pin tool design, pin height, and pin shoulder diameter and related control conditions. The frictional heating with rotational speeds of the pin tool as it plunges into the material and the ensuing plastic flow arising during the traverse of the welding faying surfaces provide the known special advantages of the FSW process in the area of this new advanced joining technology.

  14. Microstructures and properties of non-preheated hardfacing welding

    Institute of Scientific and Technical Information of China (English)

    Yang Shanglei; Zou Zengda; Lü Xueqin; Lou Songnian

    2007-01-01

    A new type of non-preheated hardfacing electrode was developed using H08A as the core and the coat contents including ferrotitanium, ferrovanadium, graphite, rutile etc. The microstructures and properties of hardfacing metal were systematically researched. The results show the hardness of hardfacing metal increases with increasing of ferrotitanium, ferrovanadium, graphite in the coat, but the crack resistance and processing weldability become worse. The carbides formed by arc metallurgic reaction are uniformly dispersed in the matrix structure. The phases of hardfacing metal consist of α-Fe, γ-Fe, VC, TiC and Fe3C. The carbides are compression aggregation of TiC and VC, and their appearances present irregular block. The matrix microstructure of hardfacing metal is lath martensite. The hardfacing layers with better crack resistance and wearability are achieved and no visible cracks occur when using non-preheated electrode in continuous welding process. Hardness of hardfacing metal is more than 60HRC, and its relative wearability is five times of wearability of D667 electrode in abrasive wear test.

  15. Characteristics in Paintability of Advanced High Strength Steels

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ha Sun [POSLAB, POSCO, Gwangyang (Korea, Republic of)

    2007-06-15

    It is expected that advanced high strength steels (AHSS) would be widely used for vehicles with better performance in automotive industries. One of distinctive features of AHSS is the high value of carbon equivalent (Ceq), which results in the different properties in formability, weldability and paintability from those of common grade of steel sheets. There is an exponential relation between Ceq and electric resistance, which seems also to have correlation with the thickness of electric deposition (ED) coat. higher value of Ceq of AHSS lower the thickness of ED coat of AHSS. Some elements of AHSS such as silicon, if it is concentrated on the surface, affect negatively the formation of phosphates. In this case, silicon itself doesn't affect the phosphate, but its oxide does. This phenomenon is shown dramatically in the welding area. Arc welding or laser welding melts the base material. In the process of cooling of AHSS melt, the oxides of Si and Mn are easily concentrated on the surface of boundary between welded and non welded area because Si and Mn cold be oxidized easier than Fe. More oxide on surface results in poor phosphating and ED coating. This is more distinctive in AHSS than in mild steel. General results on paintability of AHSS would be reported, being compared to those of mild steel

  16. Resistance spot welding and weldbonding of advanced high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Weber, G.; Gaul, H.; Rethmeier, M. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany). Div. V.5 ' ' Safety of Joined Components' ' ; Thommes, H.; Hahn, O. [Paderborn Univ. (Germany). Fakultaet fuer Maschinenbau

    2010-11-15

    The resistance spot welding procedure is one of the most important joining techniques in lightweight car body shell mass production. Especially for newly developed high strength multiphase steels, also called advanced high strength steels (AHSS), and ultra high strength steels (UHSS), this joining technique has more advantages than other thermal and mechanical joining procedures for thin steel sheets. Additionally, the technique of adhesive bonding and its combination with the technique of resistance spot welding called weldbonding becomes more and more important. One of the targets of the contribution is to show the influence of joined advanced high strength steels on the process reliability for both the resistance spot welding process and the weldbonding process. Based on welding current ranges and on results of electrode wear tests, statements concerning the resistance spot weldability of some special AHSS will be given. The mechanical behaviour of spot welded and weldbonded joints for different AHSS will be studied. Furthermore, some statements regarding the fracture behaviour, the hardness and the fatigue behaviour of both spot welded and weldbonded joints for different AHSS will be given. Finally, some results on the mechanical properties of spot welded and weldbounded joints under corrosive attacks with be discussed. (orig.)

  17. New Forming Technologies for Autobody at POSCO

    Science.gov (United States)

    Lee, Hong-Woo; Cha, Myung-Hwan; Choi, Byung-Keun; Kim, Gyo-Sung; Park, Sung-Ho

    2011-08-01

    As development of car body with light weight and enhanced safety became one of the hottest issues in the auto industry, the advanced high strength steels have been broadly applied to various automotive parts over the last few years. Corresponding to this trend, POSCO has developed various types of cold and hot rolled AHSSs such as DP, TRIP, CP and FB, and continues to develop new types of steel in order to satisfy the requirement of OEMs more extensively. To provide optimal technical supports to customers, POSCO has developed more advanced EVI concept, which includes the concept of CE/SE, VA/VE, VI and PP as well as the conventional EVI strategy. To realize this concept, POSCO not only supports customers with material data, process guideline, and evaluation of formability, weld-ability, paint-ability and performance but also provides parts or sub-assemblies which demand highly advanced technologies. Especially, to accelerate adoption of AHSS in autobody, POSCO has tried to come up with optimal solutions to AHSS forming. Application of conventional forming technologies has been restricted more and more by relatively low formability of AHSS with high tensile-strength. To overcome the limitation in the forming, POSCO has recently developed new forming technologies such as hydro-forming, hot press forming, roll forming and form forming. In this paper, tailored strength HPF, hydroformed torsion beam axle and multi-directional roll forming are introduced as examples of new forming technologies.

  18. 焊接工艺对40CrMnMo小齿轮补焊抗裂性的影响%The Influence of Welding Technology to CrackResistance of Forged Steel 40CrMnMo Pinion Defects Welding Repair

    Institute of Scientific and Technical Information of China (English)

    李家森; 赵宏明

    2014-01-01

    The cracks about forged steel 40CrMnMo pinion was introduced , and the weldability of 40CrMnMo was analyzed . Take defects welding repair of forged steel 40CrMnMo Pinion for example , the connection between the welding technology and the crack resistance was expounded .Pointed out that the welding technology has a direct impact to improve carack resistance , only compiled reasonable welding technology to ensure welding quality .%本文介绍了锻钢40CrMnMo 小齿轮裂纹情况,分析了40CrMnMo 的焊接性,以40CrMnMo小齿轮补焊为例,阐述了焊接工艺与抗裂性的关系。指出焊接工艺对提高抗裂性有直接影响,只有制定合理的焊接工艺才能确保焊接质量。

  19. Deign of Experiment and Optimization of Plasma Transferred Arc Hardfacing on Structural Steel with Titanium Carbide

    Directory of Open Access Journals (Sweden)

    S. Balamurugan

    2014-03-01

    Full Text Available The aim of the Plasma Transferred Arc (PTA hardfacing process is improving a technical surface locally with a dedicated material; Hardfacing became an issue of intense development related to wear resistant application. The hardfacing procedures can be differentiated by the intensity of mixture with the base body, which is usually increasing along with an increasing fusion efficiency rate. Nearly all kinds of weldable materials can be hardfaced and mostly all types of known wear resistant metals in combination can be used as hardfacing materials. The PTA hardfacing process has been widely employed due to several advantages such as higher volume of metal deposition rates and achieving very low dilution level. Heat input which influences dilution can be controlled by proper selection of PTA process parameters. In this study, an attempt has been made to analyze PTA hardfacing of IS: 2062 structural steel with Titanium Carbide (TiC. Experiments were conducted based on a fully replicable five-factor, five-level central composite rotatable design. Mathematical models were developed using response surface methodology to study the effects of PTA hardfacing process parameters such as welding current, welding speed ,powder feed rate, oscillation width and pre heat temperature on bead geometry parameters like penetration, reinforcement, bead width and dilution. Direct and interaction effects of PTA process parameters on bead geometry were analyzed. From mathematical model, the process parameters were optimized.

  20. Strength and toughness improvement of low-alloy steel for nuclear applications

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H. C.; Lee, S. H.; Ku, Y. M.; Lee, B. J. [Seoul National University, Seoul (Korea)

    2002-04-01

    Low carbon low alloy steels are used in nuclear power plants as pressure vessel, steam generator, etc. Nuclear pressure vessel material requires good combination of strength/ toughness, good weldability and high resistance to neutron irradiation and corrosion fatigue. For SA508III steels, most widely used in the production of nuclear power plant, attaining good toughness prior to service is one of the utmost designing goals. This work has been carried out by the combination of thermodynamic calculation, microstructural observation and evaluation of designed alloy, and the evaluation of HAZ characteristics. In this work, the means of alloy design developed in the previous study were adopted. Cr/Mo contents was controlled and Ni contents was increased to improve toughness. High toughness values were obtained in designed low carbon steels, with higher strength level than that of SA508III steels. A high CVN energy of 220J was obtained at -100 .deg. C, and a low DBTT of about-100 .deg. C was obtained in 60Cr alloy prepared in this work. 38 refs., 61 figs., 32 tabs. (Author)

  1. Development of Fine-Grained, Low-Carbon Bainitic Steels with High Strength and Toughness Produced Through the Conventional Hot-Rolling and Air-Cooling

    Science.gov (United States)

    Dhua, Sanjay Kumar; Sarkar, Partha Pratim; Saxena, Atul; Jha, Bimal Kumar

    2016-12-01

    Low-carbon bainitic steels have created enormous interest among scientists across the world in the past few decades because of their high strength, toughness, and weldability replacing the conventional quenched and tempered medium-carbon steels. Three experimental steels with varying alloy additions were made in a 100-kg laboratory induction furnace and cast into 100-mm-diameter cylindrical ingots. These ingots were hot-rolled and air-cooled to 6-mm plates in an experimental rolling mill with selected thermomechanical parameters. Steels processed through this process provided an ultrafine low-carbon bainitic microstructure with maximum yield strength (YS) and ultimate tensile strength (UTS) 575 and 705 MPa, respectively. The Charpy impact toughness of the experimental steels was excellent, and at 253 K (-20 °C), it varied from 114 to 170 Joules. Cu-B-added steel was found to give an optimum combination of strength, YS-575 MPa, and toughness, 114 J at 253 K (-20 °C). Thus, fine-grained, low-carbon bainitic steels could be developed with a proper combination of alloying elements and thermomechanical parameters even by air-cooling.

  2. Analysis of the influence of the multipass welding, welding preheat and welding post heat treatments on the behaviour of GMAW joints of HARDOX 400 microalloyed steel; Influencia de la tecnica de soldaduramultipasada y de los tratamientos termicos de precalentamiento y post-soldadura en el comportamiento de uniones GMAW de un acero microaleado HARDOX 400

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, A.; Miguel, V.; Coello, J.; Navarro, A.; Calatayud, A.; Manjabacas, M. C.

    2011-07-01

    The microalloyed steels may be supplied in a hardened state. In these cases, the weldability can be improved by pre-heat and/or post-heat welding treatments. In this paper, the effect of those treatments and the influence of multipass welding on GMAW joints behavior are analyzed for a Hardox 400 microalloyed steel. The microstructure evaluation of the different heat affected zones of the steel has been made and the mechanical properties of those zones are obtained for different conditions as it has been mentioned. The obtained results indicate that preheating the steel leads to a beneficial action that consists on the distance increasing from the bead to the zone in which the hardness is lowest. The post heat treatment strengthens that zone and improves the joint plasticity. This benefit is higher if the joint has been made with preheating. Multipass welding has not been found to have any advantage if it is compared to a single welding pass. (Author) 18 refs.

  3. Development of electromagnetic welding facility of flat plates for nuclear industry

    Science.gov (United States)

    Kumar, Rajesh; Sahoo, Subhanarayan; Sarkar, Biswanath; Shyam, Anurag

    2017-04-01

    Electromagnetic pulse welding (EMPW) process, one of high speed welding process uses electromagnetic force from discharged current through working coil, which develops a repulsive force between the induced current flowing parallel and in opposite direction. For achieving the successful weldment using this process the design of working coil is the most important factor due to high magnetic field on surface of work piece. In case of high quality flat plate welding factors such as impact velocity, angle of impact standoff distance, thickness of flyer and overlap length have to be chosen carefully. EMPW has wide applications in nuclear industry, automotive industry, aerospace, electrical industries. However formability and weldability still remain major issues. Due to ease in controlling the magnetic field enveloped inside tubes, the EMPW has been widely used for tube welding. In case of flat components control of magnetic field is difficult. Hence the application of EMPW gets restricted. The present work attempts to make a novel contribution by investigating the effect of process parameters on welding quality of flat plates. The work emphasizes the approaches and engineering calculations required to effectively use of actuator in EMPW of flat components.

  4. A Review of Similar and Dissimilar Micro-joining of Nitinol

    Science.gov (United States)

    Deepan Bharathi Kannan, T.; Ramesh, T.; Sathiya, P.

    2016-04-01

    NiTinol belongs to a class of smart materials which has a wide range of applications in the field of automotive, aerospace, biomedical, robotics, etc., owing to the growing trend in miniaturization of components. Micro-joining is becoming one of the important and familiar processes in the fabrication of miniaturized components. Recently, effective micro-joining of thin sheets has been gaining a lot of interest among researchers. In this article, the research and progress in micro-joining of NiTinol to itself and other metals are reviewed at different aspects. To date, laser welding, tungsten inert gas welding, and resistance welding have been used to a large extent in investigating the weldability of NiTinol alloys. Some important welding parameters used in micro joining by various researchers and their effects on weld qualities are detailed in this review. Metallurgical aspects, mechanical properties and corrosion aspects of micro-joined NiTinol sheets/wires are discussed. The aim of this report is to review the recent progress in micro-joining of NiTinol and to provide a basis for follow-on research.

  5. Secondary Austenite Morphologies in Fusion Zone of Welded Joint after Postweld Heat Treatment with a Continuous Wave Laser

    Institute of Scientific and Technical Information of China (English)

    Heping Liu; Xuejun Jin

    2012-01-01

    In order to improve the weldability of duplex stainless steels,obtaining more secondary austenite in the weld metal is an effective way.Therefore,optimizing the secondary austenite by changing its morphology,volume fraction and stability may be expected to enhance the ductility of the weld.The secondary austenite morphologies in the fusion zone of the laser continuously heat treated welds of 2205 duplex stainless steel were investigated.The secondary austenite morphologies were found to be influenced by different laser power level.The secondary austenite with penniform,freely grown and dendritic shape appeared in the course of 4,6 and 8 kW continuous heat treatment,respectively.It was found that there were three kinds of morphologies of secondary austenite in the fusion zone treated by different power,i.e.,widmannst¨atten austenite,grain boundary austenite and intragranular austenite.The results demonstrated that the mechanism of the secondary austenite formation was a displacement mechanism during the initial austenite lath formation and a diffusion mechanism during cooling.The nitrides provided the nitrogen for the transformation and at the same time acted as nucleation sites for the secondary austenite.

  6. Analysis and Comparison of Friction Stir Welding and Laser Assisted Friction Stir Welding of Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Sabina Luisa Campanelli

    2013-12-01

    Full Text Available Friction Stir Welding (FSW is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW is a combination in which the FSW is the dominant welding process and the laser pre-heats the weld. In this work FSW and LAFSW tests were conducted on 6 mm thick 5754H111 aluminum alloy plates in butt joint configuration. LAFSW is studied firstly to demonstrate the weldability of aluminum alloy using that technique. Secondly, process parameters, such as laser power and temperature gradient are investigated in order to evaluate changes in microstructure, micro-hardness, residual stress, and tensile properties. Once the possibility to achieve sound weld using LAFSW is demonstrated, it will be possible to explore the benefits for tool wear, higher welding speeds, and lower clamping force.

  7. Influence of pin geometry on mechanical and structural properties of butt friction stir welded 2024-T351 aluminum alloy

    Directory of Open Access Journals (Sweden)

    Radisavljević Igor Z.

    2015-01-01

    Full Text Available The aim of this work was to investigate the combined effect of small difference in pin geometry, together with rotation and welding speed on the weldability, mechanical and structural properties of FSW 2024-T351 Al plates. The only difference in tool pin design was the shape of thread: regular and rounded. Specimens were welded using rotation rate of 750 rev/min and welding speeds of 73 and 93 mm/min. In all four cases, specimens were defect free, with good or acceptable weld surface. Modification in pin design showed strong influence on macro structure and hardness distribution. Weak places are identified as low hardness zone, close to the nugget zone and are in good agreement with fracture location in tensile testing. Weld efficiency, as a measure of weld quality, are better in case of 310 tool, while UTS values can differ up to 13% for the equal welding parameters. Therefore, it can be assumed that small modification in tool design, particularly in pin geometry, can have great influence on weld formation and mechanical properties.

  8. Automatic welding technologies for long-distance pipelines by use of all-position self-shielded flux cored wires

    Directory of Open Access Journals (Sweden)

    Zeng Huilin

    2014-10-01

    Full Text Available In order to realize the automatic welding of pipes in a complex operation environment, an automatic welding system has been developed by use of all-position self-shielded flux cored wires due to their advantages, such as all-position weldability, good detachability, arc's stability, low incomplete fusion, no need for welding protective gas or protection against wind when the wind speed is < 8 m/s. This system consists of a welding carrier, a guide rail, an auto-control system, a welding source, a wire feeder, and so on. Welding experiments with this system were performed on the X-80 pipeline steel to determine proper welding parameters. The welding technique comprises root welding, filling welding and cover welding and their welding parameters were obtained from experimental analysis. On this basis, the mechanical properties tests were carried out on welded joints in this case. Results show that this system can help improve the continuity and stability of the whole welding process and the welded joints' inherent quality, appearance shape, and mechanical performance can all meet the welding criteria for X-80 pipeline steel; with no need for windbreak fences, the overall welding cost will be sharply reduced. Meanwhile, more positive proposals were presented herein for the further research and development of this self-shielded flux core wires.

  9. Effect of Notch Location on Fatigue Life Prediction of Strength Mismatched HSLA Steel Weldments

    Institute of Scientific and Technical Information of China (English)

    S. Ravi; V. Balasubramanian; S. Nemat Nasser

    2004-01-01

    Welding of high strength low alloy steels (HSLA) involves usage of Iow, even and high strength filler materials (electrodes) than the parent material depending on the application of the welded structures and the availability of the filler material. In the present investigation, the fatigue crack growth behaviour of weld metal (WM) and heat affected zone (HAZ) regions of under matched (UM), equal matched (EM) and over matched (OM)joints has been studied. The base material used in this investigation is HSLA-80 steel of weldable grade. Shielded metal arc welding (SMAW) process has been used to fabricate the butt joints. Centre cracked tension (CCT) specimen has been used to evaluate the fatigue crack growth behaviour of the welded joints. Fatigue crack growth experiments have been conducted using servo hydraulic controlled fatigue testing machine at constant amplitude loading (R=0). A method has been proposed to predict the fatigue life of HSLA steel welds using fracture mechanics approach by incorporating influences of mismatch ratio (MMR) and notch location.

  10. Hardness and microstructural characterization of API 5L X70 steel pipes welded by HF/ERW process; Caracterizacao microestrutural e de dureza em tubos de aco API 5L X70 soldados pelo processo HF/ERW

    Energy Technology Data Exchange (ETDEWEB)

    Calcada, Mauricio Vieira; Voorwald, Herman Jacobus Cornelis; Nascimento, Marcelino Pereira do [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia

    2010-07-01

    The materials that stand in the manufacture of steel pipes are called API, that should have, high mechanical resistance, high corrosion resistance, high fatigue resistance, good weldability, and other properties. Thus, the purpose of this project was to evaluate the microstructure and hardness of welded joints by the HF/ERW process of API 5L X70 steel pipes. The microstructural analysis was performed using a surface finish with grit sizes from 220 to 25 {mu}m e polishing with diamond paste from 9 {mu}m to 0.05 {mu}m; the revelation was made with 3% Nital attack. The Vickers hardness was performed across the welded joint by 33 points to indentation. The results were: 80.5 {+-} 3.4% of ferrite and 19.5 {+-} 3.4% of perlite for microanalysis. As for hardness, the values were: 215.69 HV10 for weld line, 218.65 HV10 for ZTA and 218.95 HV10 for base metal. (author)

  11. Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys

    Directory of Open Access Journals (Sweden)

    Thomas Gietzelt

    2016-11-01

    Full Text Available Normally, the weldability of aluminum alloys is ruled by the temperature range of solidification of an alloy according to its composition by the formation of hot cracks due to thermal shrinkage. However, for materials at nonequilibrium conditions, advantage can be taken by multiple phase formation, leading to an annihilation of temperature stress at the microscopic scale, preventing hot cracks even for alloys with extreme melting range. In this paper, several spray-compacted hypereutectic aluminum alloys were laser welded. Besides different silicon contents, additional alloying elements like copper, iron and nickel were present in some alloys, affecting the microstructure. The microstructure was investigated at the delivery state of spray-compacted material as well as for a wide range of welding speeds ranging from 0.5 to 10 m/min, respectively. The impact of speed on phase composition and morphology was studied at different disequilibrium solidification conditions. At high welding velocity, a close-meshed network of eutectic Al-Si-composition was observed, whereas the matrix is filled with nearly pure aluminum, helping to diminish the thermal stress during accelerated solidification. Primary solidified silicon was found, however, containing considerable amounts of aluminum, which was not expected from phase diagrams obtained at the thermodynamic equilibrium.

  12. Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

    Directory of Open Access Journals (Sweden)

    Koray Yurtisik

    2013-09-01

    Full Text Available Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure without compromising the welding efficiency. 11.1 mm-thick standard duplex stainless steel plates were joined in a single-pass using this novel technique. Same plates were also subjected to conventional gas metal arc and plasma arc welding processes, providing benchmarks for the investigation of the weldability of the material. In the first place, the hybrid welding process enabled us to achieve less heat input compared to gas metal arc welding. Consequently, the precipitation of secondary phases, which are known to be detrimental to the toughness and corrosion resistance of duplex stainless steels, was significantly suppressed in both fusion and heat affected zones. Secondly, contrary to other keyhole techniques, proper cooling time and weld metal chemistry were achieved during the process, facilitating sufficient reconstructive transformation of austenite in the ferrite phase.

  13. Overview on the welding technologies of CLAM steel and the DFLL TBM fabrication

    Directory of Open Access Journals (Sweden)

    Junyu Zhang

    2016-12-01

    Full Text Available Dual Functional Lithium Lead (DFLL blanket was proposed for its advantages of high energy exchange efficiency and on-line tritium extraction, and it was selected as the candidate test blanket module (TBM for China Fusion Engineering Test Reactor (CFETR and the blanket for Fusion Design Study (FDS series fusion reactors. Considering the influence of high energy fusion neutron irradiation and high heat flux thermal load on the blanket, China Low Activation Martensitic (CLAM steel was selected as the structural material for DFLL blanket. The structure of the blanket and the cooling internal components were pretty complicated. Meanwhile, high precision and reliability were required in the blanket fabrication. Therefore, several welding techniques, such as hot isostatic pressing diffusion bonding, tungsten inner gas welding, electron beam welding and laser beam welding were developed for the fabrication of cooling internals and the assembly of the blanket. In this work, the weldability on CLAM steel by different welding methods and the properties of as-welded and post-weld heat-treated joints were investigated. Meanwhile, the welding schemes and the assembly strategy for TBM fabrication were raised. Many tests and research efforts on scheme feasibility, process standardization, component qualification and blanket assembly were reviewed.

  14. Current situation and properties of ultra-high strength steel for automotive use in Japan; Situation actuelle et proprietes de l'acier a ultra haute resistance pour utilisation automobile au Japon

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, K. [Nippon Steel Corp., Tokyo (Japan)

    2003-08-01

    Ultra-high strength steels with a tensile strength of 1,000 MPa to 1,200 MPa have been used for bumper and door beam since 15 years in Japan. Recently, it has been tried to apply these steels to reinforcements such as B-pillars inner and so on. The application of these types of steel tends to spread. Their formability, weldability and fatigue properties are described. Formability of ultra-high strength steel is different from that of mild steel, and it is governed by local elongation or stretch flange-ability that can be evaluated by bend-ability. Local elongation or stretch flange-ability has a negative correlation with total elongation. When strength exceeds 1,000 MPa, delayed fracture tends to occur. However, when measures to avoid delayed fracture are taken, there are no application examples of ultra-high strength steel sheet with 1,500 MPa tensile strength restricted by the danger of delayed fracture. (author)

  15. Microstructural characteristics of the laser welded joint of ITER correction coil sub case

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Chao, E-mail: fangchao@ipp.ac.cn [ASIPP, Shushan Hu Road 350, Hefei, Anhui 230031 (China); Lappeenranta University of Technology, Skinnarilankatu 34, 53850 Lappeenranta (Finland); Song, Yuntao; Wei, Jing; Xin, Jijun [ASIPP, Shushan Hu Road 350, Hefei, Anhui 230031 (China); Wu, Huapeng; Handroos, Hekki; Salminen, Antti [Lappeenranta University of Technology, Skinnarilankatu 34, 53850 Lappeenranta (Finland); Li, Hongwei [ITER China, 15B Fuxing Road, Beijing 100862 (China); Libeyre, Paul; Dolgetta, Nello [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France)

    2015-10-15

    Highlights: • The multi-pass laser welding was developed for the ITER CC case manufacture. • The laser welding procedure was studied and optimized. • The microstructural characteristic of the welded joint was discussed. - Abstract: The ITER correction coil (CC) case reinforces the winding packs against the electromagnetic loads, minimizes stresses and deformations to the winding pack. The cases are made of high strength and high toughness austenitic stainless steel (316LN) hot rolled heavy plate and have a thickness of 20 mm. Considering the small cross-section and large dimensions of the case, deformation of the case when welding becomes a challenge in the case manufacturing. Therefore, laser welding was developed as the main welding technology for manufacturing. In this paper, multi-pass laser welding technology is used, the laser weldability of a 20 mm thick 316LN austenitic stainless steel plate is studied and the microstructure of the welded joint is analyzed. The welding experiment used an YLS-6000 fiber laser (IPG) and weld filler of 316LMn to match the base metal was used. The result shows that the welded joint has no obvious surface and internal defects based on the optimized welding parameters. The weld joint have a fine austenite microstructure and display columnar dendrites and cellular grains with strong directional characteristics. No apparent heat affected zone is observed and approximately 2 μm an austenite microstructure of the fusion line is clearly presented.

  16. PINCH WELD TESTING TO SUPPORT CHANGE IN MANUFACTURING OIL AT THE KCP

    Energy Technology Data Exchange (ETDEWEB)

    Korinko, P; David Maxwell, D

    2008-02-28

    This task supports the change from an oil mixture termed 50:50 oil (an equal parts mixture of Milpro 634 and Pennex N47) to a new oil mixture (Castrol Illocut 334). This change was necessitated by a KCP vendor no longer supplying the Pennex N47 component of the 50-50. In order to continue production of machined parts, a detailed process was followed to ensure that high quality parts could be manufactured and that the cutting oil selected would provide acceptable human performance characteristics, e.g., skin irritability, smell, etc. A prime consideration in changing the oil was that no apparent change in the pinch weldability of the fill stems fabricated using the new oil and process parameters, if any, be observed. A two part approach, as detailed in the plan shown in Appendix B, was used to qualify the effect of the process on pinch weld characteristics. In the first phase, ref. 1., the weld parameter window was defined using fill stems made from 304L, 21-6-9, and 316 stainless steel. These weld conditions were then subsequently used for the Castrol Illocut 334 machined fill stems. The results of this activity are reported in this document. A follow-on task of welding in the facility was requested by one of the design agencies and this will be completed and reported separately.

  17. Ta/TA6V heterogeneous welding. Study of the formation and the metallurgical properties of the melted zones; Soudage heterogene Ta/TA6V Etude de la formation et des proprietes metallurgiques des zones fondues

    Energy Technology Data Exchange (ETDEWEB)

    Malicrot, A.; Naudy, P.; Durut, L. [CEA Valduc, 21120 Is-sur-Tille (France); Grevey, D. [Pole Laser Creusot Bourgogne, 71200 Le Creusot (France); Daloz, D. [Ecole des Mines de Nancy, 54000 Nancy (France)

    2006-07-01

    The welding laboratory of the department of manufacturing and nuclear technologies is in charge to assemble prototype objects which appeal to a lot of materials as for instance titanium or tantalum. The autogenous weldability of these two materials is relatively well known nowadays, by laser beam or electrons beam. On the other hand, the heterogeneous welding is most difficult on account of the important differences of the thermophysical and metallurgical properties of the two involved materials. This work deals more particularly with the Nd:YAG laser welding of tantalum with the titanium alloy TA6V. Two modes of energy contribution are considered: impulsional and continuous. The aim of this work is to finely characterized, in a metallurgical point of view, the melted zones in order to control their composition (constitution and distribution of the phases in presence, identification of the eventual defects), as well as the reactional processes occurring in the liquid bath during and after the interaction of the laser beam with the matter. Thus, a first study has been carried out at the macroscopic scale in order to obtain global views of the melted zones. The magnification is then strongly increased for analyzing the weldings at the microstructure scale. (O.M.)

  18. Austenitic Steels at Low Temperature: Joint International Cryogenic Engineering Conference and International Cryogenic Materials Conference

    CERN Document Server

    Horiuchi, T; ICEC-ICMC

    1983-01-01

    The need for alternate energy sources has led to the develop­ ment of prototype fusion and MHD reactors. Both possible energy systems in current designs usually require the use of magnetic fields for plasma confinement and concentration. For the creation and maintenance of large 5 to 15 tesla magnetic fields, supercon­ ducting magnets appear more economical. But the high magnetic fields create large forces, and the complexities of the conceptual reactors create severe space restrictions. The combination of re­ quirements, plus the desire to keep construction costs at a mini­ mum, has created a need for stronger structural alloys for service at liquid helium temperature (4 K). The complexity of the required structures requires that these alloys be weldable. Furthermore, since the plasma is influenced by magnetic fields and since magnet­ ic forces from the use of ferromagnetic materials in many configur­ ations may be additive, the best structural alloy for most applica­ tions should be nonmagnetic. Thes...

  19. Efeito do tipo de revestimento na soldagem a ponto de aços galvanizados Effect of coating type on spot welding of galvanized steel

    Directory of Open Access Journals (Sweden)

    Tarcélio Anício da Silva

    2010-09-01

    -Cu (brass. Spot welding tests were carried out in IF steels coated in an industrial hot-dip galvanizing line with pure zinc (GI and a Zn-Fe alloy (GA. Three welding joints were evaluated: GA/GA, GI/GI and GA/GI. Dynamic weldability diagrams and electrode life were determined for each kind of joint. The results indicated that welding current increased more quickly with the number of welds for the GI/ GI joints. This result was associated with the fastest contamination of the electrode by zinc. For the GA/GI joints, welding current levels for adequate welding increased faster than for GA/GA joints but slower than for GI/GI joints. In general, the spot welding tests with GA/GI joints presented results closer to that of the GA/GA joints than to the spot welding tests with GI/GI joints. Such results showed the positive influence of the GA coating, even for joints including both coatings to improve the spot weldability of zinc coated steels.

  20. Uma breve revisão histórica do desenvolvimento da soldagem dos aços API para tubulações A brief history review of development on API steels welding for pipeline

    Directory of Open Access Journals (Sweden)

    Jaime Casanova Soeiro Junior

    2013-06-01

    Full Text Available Este trabalho enfoca o desenvolvimento dos aços API para tubulações desde o aço API 5L X42, desenvolvido em 1948, através de laminação a quente seguida de tratamento térmico. Desde então foram feitos diferentes desenvolvimentos visando aumentar a resistência mecânica e a tenacidade, além de melhorar a soldabilidade. Entre eles, a adição de elementos de liga, produzindo os aços ARBL e a utilização de rotas de processamento termomecânico durante a laminação. Inicialmente a rota utilizada era a laminação a quente controlada (TMCR, com utilização de elemento microligante como Nb para os aços X60 e o conjunto Nb e V para os aços X65 e X70, associado a uma redução do teor de carbono. Posteriormente foi implantada a rota de fabricação do aço por laminação controlada seguida de resfriamento controlado (TMCP, com redução de carbono e adição de Nb e Ti para os aços X80, e adições de Mo, Nb, Be Ti para os X100. A redução do carbono foi motivada também para melhorar a sua soldabilidade e, por este motivo, estes aços são soldados por diferentes processos de soldagem, como o eletrodo revestido. Desenvolvimentos recentes com raiz feita com MAG-TC e enchimento com arame tubular tem dado resultados animadores.This paper is a brief history on the development of pipelines steels since the API 5L X42 steel, developed in 1948 by hot rolling followed by heat treatment. Subsequently different developments were made to increase the strength and toughness of these materials, and to improve their weldability. Among them, the addition of microalloying elements, producing HSLA steels and thermomechanical processing routes during hot rolling. Initially the route used was the controlled hot rolling (TMCR, together with microalloying element such as Nb for X60 steel and Nb plus V for X65 and X70 steels, associated with a reduction in carbon content. Later, the thermomechanical controlled process (TMCP manufacturing route was

  1. Tungsten as an innovative alloy element in the development of seamless tubular steels; Wolfram als neuartiges Legierungselement bei der Entwicklung von nahtlosen Leitungsrohrstaehlen

    Energy Technology Data Exchange (ETDEWEB)

    Pardun, M. [Mannesmann Forschungsinstitut, Duisburg (Germany); Vallourec and Mannesmann Tubes, Muelheim (Germany); Kloster, G.; Koschlig, B.; Niederhoff, K. [Vallourec and Mannesmann Tubes, Duesseldorf (Germany)

    2002-07-01

    This article presents a new alloying concept, which has been developed by Vallourec and Mannesmann Tubes together with the Mannesmann Research Institute for seamless linepipe. The key role of this concept is played by the alloying element tungsten. The impulse for using tungsten, which is known to be a precipitation hardener, derived from its property to stabilise the yield strength at higher service temperatures. Different laboratory heats with tungsten contents between 0.25 and 0.50% and C-equivalents acc. to IIW between 0.33 and 0.42% were tested. Apart from the more general aspect of applicability of tungsten for seamless linepipe steels and its influence on the yield strength at elevated temperatures, special attention was paid to the following targets: Development of a steel for seamless linepipe of API Grade X60 to X70 with low Carbon equivalent (tungsten is not included in the common formulas), Investigation of the weldability of tungsten alloyed steels, Improvement of corrosion resistance under sour gas conditions (substitution of manganese, which is supposed to promote segregation, by tungsten) In this paper a comprehensive overview is given about the hole development work, from the laboratory step up to the first successful mill rolling at the Pilger mill Duesseldorf-Rath of the Vallourec and Mannesmann Tubes. Particular attention is paid not only to the production of pipes and description of mechanical properties but also to corrosion properties and weldability. (orig.) [German] Im vorliegenden Beitrag wird ueber ein neuartiges Legierungskonzept berichtet, das bei Vallourec and Mannesmann Tubes in Zusammenarbeit mit dem Mannesmann Forschungsinstitut MFI fuer nahtlos gewalzte Leitungsrohre entwickelt wurde. Dabei spielt das Legierungselement Wolfram eine entscheidende Rolle. Den Ahstoss fuer den Einsatz von Wolfram lieferte die Erkenntnis, dass das als ausscheidungshaertend bekannte Element Wolfram bei warmfesten Staehlen die Streckgrenze bei erhoehten

  2. Development of a High Chromium Ni-Base Filler Metal Resistant to Ductility Dip Cracking and Solidification Cracking

    Science.gov (United States)

    Hope, Adam T.

    Many nuclear reactor components previously constructed with Ni-based alloys containing 20 wt% Cr have been found to be susceptible to stress corrosion cracking. The nuclear power industry now uses high chromium (˜30wt%) Ni-based filler metals to mitigate stress corrosion cracking. Current alloys are plagued with weldability issues, either solidification cracking or ductility dip cracking (DDC). Solidification cracking is related to solidification temperature range and the DDC is related to the fraction eutectic present in the microstructure. It was determined that an optimal alloy should have a solidification temperature range less than 150°C and at least 2% volume fraction eutectic. Due to the nature of the Nb rich eutectic that forms, it is difficult to avoid both cracking types simultaneously. Through computational modeling, alternative eutectic forming elements, Hf and Ta, have been identified as replacements for Nb in such alloys. Compositions have been optimized through a combination of computational and experimental techniques combined with a design of experiment methodology. Small buttons were melted using commercially pure materials in a copper hearth to obtain the desired compositions. These buttons were then subjected to a gas tungsten arc spot weld. A type C thermocouple was used to acquire the cooling history during the solidification process. The cooling curves were processed using Single Sensor Differential Thermal Analysis to determine the solidification temperature range, and indicator of solidification cracking susceptibility. Metallography was performed to determine the fraction eutectic present, an indicator of DDC resistance. The optimal level of Hf to resist cracking was found to be 0.25 wt%. The optimal level of Ta was found to be 4 wt%. gamma/MC type eutectics were found to form first in all Nb, Ta, and Hf-bearing compositions. Depending on Fe and Cr content, gamma/Laves eutectic was sometimes found in Nb and Ta-bearing compositions, while

  3. Design and Fabrication Technique of the Key Components for Very High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jin; Song, Ki Nam; Kim, Yong Wan

    2006-12-15

    The gas outlet temperature of Very High Temperature Reactor (VHTR) may be beyond the capability of conventional metallic materials. The requirement of the gas outlet temperature of 950 .deg. C will result in operating temperatures for metallic core components that will approach very high temperature on some cases. The materials that are capable of withstanding this temperature should be prepared, or nonmetallic materials will be required for limited components. The Ni-base alloys such as Alloy 617, Hastelloy X, XR, Incoloy 800H, and Haynes 230 are being investigated to apply them on components operated in high temperature. Currently available national and international codes and procedures are needed reviewed to design the components for HTGR/VHTR. Seven codes and procedures, including five ASME Codes and Code cases, one French code (RCC-MR), and on British Procedure (R5) were reviewed. The scope of the code and code cases needs to be expanded to include the materials with allowable temperatures of 950 .deg. C and higher. The selection of compact heat exchangers technology depends on the operating conditions such as pressure, flow rates, temperature, but also on other parameters such as fouling, corrosion, compactness, weight, maintenance and reliability. Welding, brazing, and diffusion bonding are considered proper joining processes for the heat exchanger operating in the high temperature and high pressure conditions without leakage. Because VHTRs require high temperature operations, various controlled materials, thick vessels, dissimilar metal joints, and precise controls of microstructure in weldment, the more advanced joining processes are needed than PWRs. The improved solid joining techniques are considered for the IHX fabrication. The weldability for Alloy 617 and Haynes 230 using GTAW and SMAW processes was investigated by CEA.

  4. Non-contact inline monitoring of thermoplastic CFRP tape quality using air-coupled ultrasound

    Science.gov (United States)

    Essig, W.; Fey, P.; Meiler, S.; Kreutzbruck, M.

    2017-02-01

    Beginning with the aerospace industry, fiber reinforced plastics have spread towards many applications such as automotive, civil engineering as well as sports and leisure articles. Their superior strength and stiffness to mass ratio made them the number one material for achieving high performance. Especially continuous fiber reinforced plastics allow for the construction of structures which are custom tailored to their mechanical loads by adjusting the paths of the fibers to the loading direction. The two main constituents of CFRP are carbon fibers and matrix. Two possibilities for matrix material exist: thermosetting and thermoplastic matrix. While thermosetting matrix may yield better properties with respect to thermal loads, thermoplasticity opens a wide range of applications due to weldability, shapeability, and compatibility to e.g. injection molded thermoplastic materials. Thin (0.1 mm) thermoplastic continuous fiber CFRP tapes with a width of 100 mm were examined using air-coupled ultrasound. Transducers were arranged in reflection as well as transmission setup. By slanted incidence of the ultrasound on the tape surface, guided waves were excited in the material in fiber direction and perpendicular to the fiber direction. Artificial defects - fiber cuts, matrix cuts, circular holes, low velocity impacts from tool drop, and sharp bends - were produced. Experiments on a stationary tape showed good detectability of all artificial defects by guided waves. Also the effects of variation in material properties, fiber volume content and fiber matrix adhesion being the most relevant, on guided wave propagation were examined, to allow for quality assessment. Guided wave measurements were supported by destructive analysis. Also an apparatus containing one endless loop of CFRP tape was constructed and built to simulate inline testing of CFRP tapes, as it would be employed in a CFRP tape production environment or at a CFRP tape processing facility. The influences of tape

  5. Study on the Effect of Laser Welding Parameters on the Microstructure and Mechanical Properties of Ultrafine Grained 304L Stainless Steel

    Directory of Open Access Journals (Sweden)

    Reihane Nafar Dehsorkhi

    2016-12-01

    Full Text Available In the present study, an ultrafine grained (UFG 304L stainless steel with the average grain size of 300 nm was produced by a combination of cold rolling and annealing. Weldability of the UFG sample was studied by Nd: YAG laser welding under different welding conditions. Taguchi experimental design was used to optimize the effect of frequency, welding time, laser current and laser pulse duration on the resultant microstructure and mechanical properties. X-ray Diffraction (XRD, Optical Microscope (OM, Scanning Electron Microscope (SEM, Transmission Electron Microscope (TEM, microhardness measurements and tension tests were conducted to characterize the sample after thermomechanical processing and laser welding. The results showed that the ultrafine grained steel had the yield strength of 1000 Mpa and the total elongation of 48%, which were almost three times higher than those of the as-received sample. The microstructure of the weld zone was shown to be a mixture of austenite and delta ferrite. The microhardness of the optimized welded sample (315 HV0.5 was found to be close to the UFG base metal (350 HV. It was also observed that the hardness of the heat affected zone (HAZ was  lower than that of the weld zone, which was related to the HAZ grain growth during laser welding. The results of optimization also showed that the welding time was the most important parameter affecting the weld strength. Overall, the study showed that laser welding could be an appropriate and alternative welding technique for the joining of UFG steels.

  6. Vacuum Tight Threaded Junctions (VTTJ): A new solution for reliable heterogeneous junctions in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Agostinetti, P., E-mail: piero.agostinetti@igi.cnr.it; Palma, M. Dalla; Agostini, F. Degli; Marcuzzi, D.; Rizzolo, A.; Rossetto, F.; Sonato, P.; Zaccaria, P.

    2015-10-15

    Highlights: • Heterogeneous junctions represent a critical issue in Nuclear Fusion experiments. • We have developed a new technique for heterogeneous junctions, called VTTJ, whose main advantages are low cost, high reliability and easiness of construction. • The VTTJ junctions have passed all the tests required by ITER for the heterogeneous junctions of the divertor. • Further tests have demonstrated wide margins for operation (up to 700 °C and 500 bar). - Abstract: A new technique, called Vacuum Tight Threaded Junction (VTTJ), has been developed and patented by Consorzio RFX, permitting to obtain low-cost and reliable non-welded junctions, able to maintain vacuum tightness also in heavy loading conditions (high temperature and high mechanical loads). The technique can be applied also if the materials to be joint are not weldable and for heterogeneous junctions (for example, between steel and copper) and has been tested up to 500 bar internal pressure and up to 700 °C, showing excellent leak tightness in vacuum conditions and high mechanical resistance. The main advantages with respect to existing technologies (for example, friction welding and electron beam welding) are an easy construction, a low cost, a precise positioning of the junction and a high repeatability of the process. Due to these advantages, the new technique has been adopted for several components of the SPIDER experiment and it is proposed for ITER, in particular for the ITER Heat and Current Drive Neutral Beam Injector and for its prototype, the MITICA experiment, to be tested at Consorzio RFX. This paper gives a detailed description of the VTTJ technique, of the samples manufactured and of the qualification tests that have been carried out so far.

  7. Stress corrosion cracking of welded joints of super-martensitic stainless steel in H{sub 2}S free environment

    Energy Technology Data Exchange (ETDEWEB)

    Hoerner, Bertrand; Bayle, Bernard; Delafosse, David [Centre Science des Materiaux et des Structures - URA CNRS 5146, ENS Mines de Saint-Etienne, 158 Cours Fauriel, 42023 Saint-Etienne cedex 02 (France); Ligier, Vincent [CRMC, INDUSTEEL Creusot, 56, rue Clemenceau, BP 56 - 71 202 Le Creusot Cedex (France)

    2004-07-01

    Due to their combination of good weldability and good mechanical properties, low carbon super-martensitic stainless steels are good candidates for oil and gas flow line applications. These alloys have already been used in slightly sour environments containing chlorides, CO{sub 2} and H{sub 2}S. The properties of a welded joint whose composition is matching or superduplex that of the base metal are investigated. The base material is the super-martensitic stainless steels medium alloy: 13Cr-4.5Ni-1.5Mo. The Heat Affected Zone (HAZ) of girth welds may be sensitive to stress corrosion cracking and presents distinct features intergranular cracking when tested in four-point bending in a sour deaerated environment at temperatures around 100 deg. C. The electrochemical properties of the medium alloy and the matching welded joint + HAZ were determined in a chloride-containing environment without H{sub 2}S. A passive film is formed on polished samples. This film is less protective for the welded joint + HAZ samples than in the base metal. Moreover, the pitting corrosion resistance is strongly decreased in the HAZ. Slow strain rate tensile tests were conducted in a de-aerated solution without H{sub 2}S. They reproduce the same type of cracking as was observed in four point bending tests in a sour environment: initiation in the HAZ and an intergranular crack with a very brittle aspect and no significant trace of corrosion. The presence H{sub 2}S is not the prevailing factor for the occurrence of cracking. Furthermore, it is not necessary to have a specific surface condition for crack initiation to occur in slow strain rate tension, as it is the case four point bend tests where initiation appears to be controlled by the surface condition (chemical and / or geometrical). Finally, a simulated PWHT strongly increase the resistance to SSC. (authors)

  8. Repair by weld of steam and gas turbine rotors made of Cr-Mo-V steel; Reparacion por soldadura de rotores de turbinas de vapor y de gas fabricados con aceros al Cr-Mo-V

    Energy Technology Data Exchange (ETDEWEB)

    Mazur C, Zdzislaw; Hernandez R, Alejando [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Orozco S, Julian; Banuelos P, Jose E. [Comision Federal de Electricidad (Mexico)

    2003-07-01

    In this article an analysis is presented of the typical damages in steam and gas turbine rotors made of Cr-Mo-V low alloy steels. An analysis of the weldability of the Cr-Mo-V steel is carried out and a classification of the possible types of repairs of the turbine rotors is presented, starting off from the causes and ways of presentation of the faults/deterioration of the rotor materials during the operation of the turbine. With base on the damages detected in the rotor of a gas turbine of 20.65 MW, the development of the repairing technology carried out by weld in site is presented. After the repair process, the rotor was put again in operation. [Spanish] En este articulo se presenta un analisis de los danos tipicos en rotores de turbinas de vapor y de gas fabricados con aceros de baja aleacion al Cr-Mo-V. Se lleva a cabo un analisis de la soldabilidad de los aceros al Cr-Mo-V y se presenta una clasificacion de los posibles tipos de reparaciones de los rotores de turbinas, partiendo de las causas y modos de presentacion de las fallas/deterioro del material de los rotores durante la operacion de la turbina. Con base en los danos detectados en el rotor de una turbina de gas de 20.65 MW, se presenta el desarrollo de la tecnologia de reparacion por soldadura llevada a cabo en sitio. Despues del proceso de reparacion, el rotor fue puesto nuevamente en servicio.

  9. An experimental study of high-hydrogen welding processes

    Directory of Open Access Journals (Sweden)

    Fydrych, Dariusz

    2015-12-01

    Full Text Available This paper presents investigation results of determination of the diffusible hydrogen content in deposited metal obtained by means of two most often used methods-the glycerin method and the mercury method. Relation has been defined between results of those methods in the area characteristic of low-hydrogen as well as high-hydrogen welding processes. Relations available in the literature do not include the diffusible hydrogen content in deposited metal greater than 35 ml/100 g. Extending the scope of analysis of the diffusible hydrogen quantity to an 80 ml/100 g level considerably simplifies carrying out the steel weldability assessment with the use of high-hydrogen processes and with welding in water environment.Este trabajo presenta los resultados de una investigación sobre la determinación del contenido de hidrógeno difusible en el material aportado mediante dos métodos: el de la glicerina (el más utilizado y el del mercurio. El contenido de dicho hidrógeno se ha definido a partir de los resultados de esos métodos en una zona con bajo contenido en hidrógeno, así como procesos de soldadura con alto contenido en hidrógeno. No hay datos disponibles en la literatura para contenidos de hidrógeno difusible en metal depositado mayores de 35 ml/100 g. Ampliando el análisis de la cantidad de dicho hidrógeno hasta los 80 ml/100 g, se simplifica considerablemente la realización de ensayos de soldabilidad del acero en procesos de alto contenido en hidrógeno así como en la soldadura en medio acuoso.

  10. La soldadura eléctrica por resistencia en la construcción de estructuras metálicas

    Directory of Open Access Journals (Sweden)

    de Heredia, Rafael

    1963-02-01

    Full Text Available Spot resistance welding procedure has been used for a long time for the construction of light weight elements in metal structures. Very recently, this procedure has begun to be successfully used for joining thicknesses adding up to 40 or 50 mm. Thus a new joining method has appeared in the fabrication of steel structures. In this paper, the author studies the principles of spot resistance welding as well as those of the welding machines which are employed in this a technique when used for large thicknesses. A thorough review is also presented on the welded seam layout and the weldability conditions for the steels. The paper describes also some constructions where resistance welding has been used.El procedimiento de soldeo por resistencia por puntos se ha venido aplicando desde hace mucho tiempo en la ejecución de elementos ligeros de construcción metálica. Actualmente se ha comenzado con éxito su utilización para unir sumas de espesores de 40 ó 50 mm. De esta manera se ha dado entrada a este medio de unión en la construcción de estructuras metálicas. A lo largo del artículo se hace un estudio de los principios de la soldadura por puntos, así como también de las máquinas que se emplean en esta modalidad aplicada al soldeo de espesores grandes. Se pasa revista también a la disposición que deben adoptar las costuras y a las condiciones que han de cumplir los materiales en cuanto a su soldabilidad. Por último, se presentan algunas realizaciones obtenidas con esta técnica.

  11. Laser Welding Characterization of Kovar and Stainless Steel Alloys as Suitable Materials for Components of Photonic Devices Packaging

    Science.gov (United States)

    Fadhali, M. M. A.; Zainal, Saktioto J.; Munajat, Y.; Jalil, A.; Rahman, R.

    2010-03-01

    The weldability of Kovar and stainless steel alloys by Nd:YAG laser beam is studied through changing of some laser beam parameters. It has been found that there is a suitable interaction of the pulsed laser beam of low power laser pulse with both the two alloys. The change of thermophysical properties with absorbed energy from the laser pulse is discussed in this paper which reports the suitability of both Kovar and stainless steel 304 as the base materials for photonic devices packaging. We used laser weld system (LW4000S from Newport) which employs Nd:YAG laser system with two simultaneous beams output for packaging 980 nm high power laser module. Results of changing both laser spot weld width and penetration depth with changing both the pulse peak power density, pulse energy and pulse duration show that there are good linear relationships between laser pulse energy or peak power density and pulse duration with laser spot weld dimensions( both laser spot weld width and penetration depth). Therefore we concluded that there should be an optimization for both the pulse peak power and pulse duration to give a suitable aspect ratio (laser spot width to penetration depth) for achieving the desired welds with suitable penetration depth and small spot width. This is to reduce the heat affected zone (HAZ) which affects the sensitive optical components. An optimum value of the power density in the order of 105 w/cm2 found to be suitable to induce melting in the welded joints without vaporization. The desired ratio can also be optimized by changing the focus position on the target material as illustrated from our measurements. A theoretical model is developed to simulate the temperature distribution during the laser pulse heating and predict the penetration depth inside the material. Samples have been investigated using SEM with EDS. The metallographic measurements on the weld spot show a suitable weld yield with reasonable weld width to depth ratio.

  12. Effect of Welding Wire Composition on Microstructure and Mechanical Properties of Welded Joint of Dissimilar Armour Al Alloy%焊丝成分对异种装甲铝合金焊接接头组织与性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘文辉; 黄浩; 周凡; 胡忠举; 欧璇

    2013-01-01

    The 2519A and 7A52 aluminum alloy plates were welded using ER5356 and ER2319 welding wire by MIG welding,and the mechanical properties and microstructure of the welded joints were studied.The results show that the weldability of the 2519A/7A52 aluminum alloy plates with ER2319 welding wire is better than that with ER5356 welding wire,and the microstructure of the weld metal are more fine with ER2319 welding wire than that with ER5356.ER2319 contains a little Ti and Zr which formed Al3Ti and Al3Zr that provide the heterogeneous nucleation sites for α (Al) in the welding pool,which can result in refining grains of the weld metal.Then,the tensile strength and the elongation of the welded joint increase.%采用ER5356及ER2319焊丝对2519A和7A52铝合金异型板进行脉冲MIG焊,并对焊接接头的力学性能和焊缝组织进行了分析.结果表明:用ER2319焊丝焊接的接头力学性能高于ER5356,ER2319焊丝细化了焊缝区的组织,其强度比采用ER5356焊丝焊接的提高了13.3%,伸长率提高了39.3%.ER2319焊丝中的微量元素Ti和Zr在焊缝中形成Al3Ti和Al3Zr,促进α(Al)非均匀形核是提高接头强度和塑性的重要原因.

  13. Effect of Post-weld Heat Treatment on the Mechanical Properties of Supermartensitic Stainless Steel Deposit

    Science.gov (United States)

    Zappa, Sebastián; Svoboda, Hernán; Surian, Estela

    2017-02-01

    Supermartensitic stainless steels have good weldability and adequate tensile property, toughness and corrosion resistance. They have been developed as an alternative technology, mainly for oil and gas industries. The final properties of a supermartensitic stainless steel deposit depend on its chemical composition and microstructure: martensite, tempered martensite, ferrite, retained austenite and carbides and/or nitrides. In these steels, the post-weld heat treatments (PWHTs) are usually double tempering ones, to ensure both complete tempering of martensite and high austenite content, to increase toughness and decrease hardness. The aim of this work was to study the effect of post-weld heat treatments (solution treatment with single and double tempering) on the mechanical properties of a supermartensitic stainless steel deposit. An all-weld metal test coupon was welded according to standard ANSI/AWS A5.22-95 using a GMAW supermartensitic stainless steel metal cored wire, under gas shielding. PWHTs were carried out varying the temperature of the first tempering treatment with and without a second tempering one, after solution treatment. All-weld metal chemical composition analysis, metallurgical characterization, hardness and tensile property measurements and Charpy-V tests were carried out. There are several factors which can be affected by the PWHTs, among them austenite content is a significant one. Different austenite contents (0-42%) were found. Microhardness, tensile property and toughness were affected with up to 15% of austenite content, by martensite tempering and carbide precipitation. The second tempering treatment seemed not to have had an important effect on the mechanical properties measured in this work.

  14. Modelling the processing of aluminium alloys in the semi-solid state

    Energy Technology Data Exchange (ETDEWEB)

    Wahlen, A. [ARC Leichtmetallkompetenzzentrum Ranshofen GmbH, Ranshofen (Austria)

    2002-07-01

    Thixoforming, an innovative technique in which metals are formed in their semi-solid state, permits the cost-efficient production of components with improved properties and performance compared to conventional pressure die casting. Since this process is still relatively new, great technical advances can be expected in the near future. These advances should allow production of near-net-shape components with good mechanical properties, combined with low manufacturing cost. Due to the distinct thixotropic flow pattern of the semi-solid slurry, high production speeds similar to those of conventional pressure die casting can be achieved, yet the disadvantages of the latter are eliminated: thixoformed components possess a good combination of strength and ductility, and they are heat-treatable and weldable. The requirement for thixotropic flow behaviour is a particular microstructure in the semi-solid state. At the onset of forming, the solid phase of the material must exhibit a globular morphology, a feature that can be produced with a novel casting technique called new rheocasting (NRC). Cast billets of several aluminium alloys and resulting microstructures show the feasibility of the chosen process variant. Constitutive models for the distinct flow behaviour of thixotropic aluminium alloys in the semi-solid state are derived with respect to temperature, strain rate and microstructure. Experimental techniques such as deformation tests, backward extrusion experiments, differential thermal analysis and quantitative metallurgy provide the necessary data to calibrate the materials models. For the implementation in a special-purpose FE software package, constitutive models for the thixotropic flow stress, the specific thixotropic flow stress, the specific heat capacity and the thermal conductivity of cast and wrought aluminium alloys in the semi-solid state are provided. For the optimization of the thixoforming manufacturing process these models were implemented in the FE

  15. Non-destructive Residual Stress Analysis Around The Weld-Joint of Fuel Cladding Materials of ZrNbMoGe Alloys

    Directory of Open Access Journals (Sweden)

    Parikin

    2003-08-01

    Full Text Available The residual stress measurements around weld-joint of ZrNbMoGe alloy have been carried out by using X-ray diffraction technique in PTBIN-BATAN. The research was performed to investigate the structure of a cladding material with high temperature corrosion resistance and good weldability. The equivalent composition of the specimens (in %wt. was 97.5%Zr1%Nb1%Mo½%Ge. Welding was carried out by using TIG (tungsten inert gas technique that completed butt-joint with a current 20 amperes. Three region tests were taken in specimen while diffraction scanning, While diffraction scanning, tests were performed on three regions, i.e., the weldcore, the heat-affected zone (HAZ and the base metal. The reference region was determined at the base metal to be compared with other regions of the specimen, in obtaining refinement structure parameters. Base metal, HAZ and weldcore were diffracted by X-ray, and lattice strain changes were calculated by using Rietveld analysis program. The results show that while the quantity of minor phases tend to increase in the direction from the base metal to the HAZ and to the weldcore, the quantity of the ZrGe phase in the HAZ is less than the quantity of the ZrMo2 phase due to tGe element evaporation. The residual stress behavior in the material shows that minor phases, i.e., Zr3Ge and ZrMo2, are more dominant than the Zr matrix. The Zr3Ge and ZrMo2 experienced sharp straining, while the Zr phase was weak-lined from HAZ to weldcore. The hydrostatic residual stress ( in around weld-joint of ZrNbMoGe alloy is compressive stress which has minimum value at about -2.73 GPa in weldcore region

  16. U.S. program on materials technology for ultra-supercritical coal power plants

    Science.gov (United States)

    Viswanathan, R.; Henry, J. F.; Tanzosh, J.; Stanko, G.; Shingledecker, J.; Vitalis, B.; Purgert, R.

    2005-06-01

    The efficiency of conventional fossil power plants is a strong function of the steam temperature and pressure. Research to increase both has been pursued worldwide, since the energy crisis in the 1970s. The need to reduce CO2 emissions has recently provided an additional incentive to increase efficiency. More recently, interest has been evinced in advanced combustion technologies utilizing oxygen instead of air for combustion. The main enabling technology in achieving the above goals is the development of stronger high temperature materials. Extensive research-and-development programs have resulted in numerous high-strength alloys for heavy section piping and for tubing needed to build boilers. The study reported on here is aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired boilers that are capable of operating with steam at temperatures of 760 °C (1400 °F) and pressures of 35 MPa (5000 psi). The economic viability of such a plant has been explored. Candidate alloys applicable to various ranges of temperatures have been identified. Stress rupture tests have been completed on the base metal and on welds to a number of alloys. Steamside oxidation tests in an autoclave at 650 °C (1200 °F) and 800 °C (1475 °F) have been completed. Fireside corrosion tests have been conducted under conditions simulating those of waterwalls and superheater/reheater tubes. The weldability and fabricability of the alloys have been investigated. The capabilities of various overlay coatings and diffusion coatings have been examined. This article provides a status report on the progress achieved to date on this project.

  17. Section 3: Optimization of a 550/690-MPa high-performance bridge steel

    Energy Technology Data Exchange (ETDEWEB)

    Magee, A.B.; Gross, J.H.; Stout, R.D. [and others

    1997-04-01

    This project to develop a high-performance bridge steel was intended to avoid susceptibility of the steel to weld heat-affected-zone cracking and therefore minimize the requirement for preheat, and to increase its fracture toughness at service temperatures. Previous studies by the Lehigh University Center for Advanced Technology for Large Structural Systems have suggested that a Cu-Ni steels with the following composition was an excellent candidate for such a bridge steel: C/0.070; Mn/1.50; P/0.009; S/0.005; Si/0.25; Cu/1.00; Ni/0.75; Cr/0.50; Mo/0.50; V/0.06; Cb/0.010. To confirm that observation, 227-kg heats of the candidate steel were melted and processed to 25- and 50-mm-thick plate by various thermomechanical practices, and the weldability and mechanical properties determined. To evaluate the feasibility of reduced alloy content, two 227-kg heats of a lower hardenability steel were melted with C reduced to 0.06, Mn to 1.25, and Mo to 0.25 and similarly processed and tested. The results indicate that the steels were not susceptible to hydrogen-induced weld-heat-affected-zone cracking when welded without preheat. Jominy end-quench tests of the higher-hardenability steel indicate that a minimum yield-strength of 690 MPa should be readily attainable in thicknesses through 50 mm and marginally at 100 mm. The toughness of the steel readily met AASHTO specifications for Zone 3 in all conditions and thicknesses, and may be sufficiently tough so that the critical crack size will minimize fatigue-crack-extension problems.

  18. Localization of welding material on Q690E low alloy high strength steel for offshore drilling platform construction%海洋钻井平台中Q690E焊材的国产化

    Institute of Scientific and Technical Information of China (English)

    王博; 陈光亮; 盛万里; 李龙

    2012-01-01

    For the large floating crane and other marine products of Q690E high strength low alloy steel welding is easy to produce cold crack, heat affected zone by heating rate and cooling rate on formation of softening zone and brittle structure easy. Welding shall be used for preheating before welding, welding thermal insulation and heat input. Analyze the weldability of Q690E low alloy high strength steel, analyze and contrast of domestic and foreign welding materials in mechanical property and the mechanical property of deposited metal and weld metal,on the reliable welding craft standard condition,the foreign welding materials which is imported from outside the country can be completely replaced by the domestic welding materials.%用于大型浮吊等海工产品的Q690E低合金高强钢焊接时易产生冷裂纹,热影响区受加热速度和冷却速度的影响易形成软化带和脆性组织.焊接时应采用焊前预热、焊后保温和较小的热输入.对比分析国产焊材和国外焊材的化学成分、熔敷金属的力学性能和焊后焊缝金属的力学性能,在可靠的焊接工艺规范下,国产焊材是完全能够替代进口焊材的.

  19. Microstructural characterization and grain refinement of AA6082 gas tungsten arc welds by scandium modified fillers

    Energy Technology Data Exchange (ETDEWEB)

    Babu, N. Kishore, E-mail: nkishorebabu@gmail.com [Joining Technology Group, Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore); Talari, Mahesh Kumar [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Pan, D.; Sun, Z.; Wei, J. [Joining Technology Group, Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore); Sivaprasad, K. [Advanced Materials Processing Laboratory, Department of Metallurgical and Materials Engineering, National Institute of Technology, Tiruchirapalli 620015, Tamil Nadu (India)

    2012-12-14

    The refinement in weld metal grain size and shape results in both improved mechanical properties (ductility and toughness) as well as a significant improvement in weldability. In the present study, the influence of scandium (Sc) additions to the fillers on the structure and mechanical properties of AA6082 gas tungsten arc (GTA) weldments were investigated. Controlled amounts of scandium as grain refiner were introduced into the molten pool of AA6082 by pre-deposited cast inserts (AA4043 and AA5356) by GTA welding. Full penetration GTA welds were prepared using alternating current (AC). It was observed that grain size decreased with increasing amounts of scandium. The grain refinement is mainly caused by the Al{sub 3}Sc particles, which act as heterogeneous nucleation of {alpha}-Al grains. It has been shown that welds prepared with AA5356 cast insert exhibited high strength and ductility when compared with other welds. The observed grain refinement was shown to result in an appreciable increase in fusion zone hardness, strength and ductility. Post-weld aging treatment resulted in improved tensile strength and hardness of the weldments and this aging response could be attributed to the weld dilution from the base metal. The slow diffusion of Sc in Al matrix and stability of Al{sub 3}Sc precipitates at elevated temperatures were suggested to be responsible for the improved high temperature yield strength of welds made from Sc modified fillers. -- Highlights: Black-Right-Pointing-Pointer Primary Al{sub 3}Sc particles resulted in grain refinement by heterogeneous nucleation. Black-Right-Pointing-Pointer Weld metal strength and hardness improved due to grain refinement caused by Sc. Black-Right-Pointing-Pointer Weld metal responded to post-weld aging treatment due to dilution from base metal. Black-Right-Pointing-Pointer Sc addition improved the high temperature mechanical properties of welds.

  20. The Reusable Load Cell with Protection Applied for Online Monitoring of Overhead Transmission Lines Based on Fiber Bragg Grating.

    Science.gov (United States)

    Ma, Guoming; Mao, Naiqiang; Li, Yabo; Jiang, Jun; Zhou, Hongyang; Li, Chengrong

    2016-06-21

    Heavy ice coating of high-voltage overhead transmission lines may lead to conductor breakage and tower collapse causing the unexpected interrupt of power supply. The optical load cell applied in ice monitoring systems is immune to electromagnetic interference and has no need of a power supply on site. Therefore, it has become a hot research topic in China and other countries. In this paper, to solve the problem of eccentric load in measurement, we adopt the shearing structure with additional grooves to improve the strain distribution and acquire good repeatability. Then, the fiber Bragg grating (FBG) with a permanent weldable package are mounted onto the front/rear groove of the elastic element by spot welding, the direction deviation of FBGs is 90° from each other to achieve temperature compensation without an extra FBG. After that, protection parts are designed to guarantee high sensitivity for a light load condition and industrial safety under a heavy load up to 65 kN. The results of tension experiments indicate that the sensitivity and resolution of the load cell is 0.1285 pm/N and 7.782 N in the conventional measuring range (0-10 kN). Heavy load tension experiments prove that the protection structure works and the sensitivity and resolution are not changed after several high load (65 kN) cycles. In addition, the experiment shows that the resolution of the sensor is 87.79 N in the large load range, allowing the parameter to be used in heavy icing monitoring.

  1. 替代镀金的环境友好型工艺%Environment-friendly technology used for replacing gold plating

    Institute of Scientific and Technical Information of China (English)

    贾成林; 张宝根; 段练

    2015-01-01

    The solvent type SP-2085C and water-soluble LP-1087C electrical contact lubrication protective agents used for replacing gold plating on copper and copper alloy substrates were introduced. Their preparation and coating processes were described. Through corrosion resistance tests (damp-heat, sulfur dioxide atmosphere, and salt spray) and electrical property tests (dielectric strength, insulation resistance, contact resistance, microwave transmission, and weldability), it was showed that, compared with the substrates coated with gold and untreated ones, the two materials not only can substitute gold plating, but also provide better corrosion resistance for copper and copper alloy surfaces than gold plating, not affecting the electrical properties and microwave transmission of products. Besides, the two materials are more environmentally friendly with lower prices.%介绍了可代替铜及铜合金基体镀金用的保护材料──溶剂型SP-2085C和水溶性LP-1087C电接触润滑保护剂,说明了其制备方法与涂覆工艺。通过抗腐蚀性试验(湿热、SO2气氛和盐雾)及电气性能试验(抗电强度、绝缘电阻、接触电阻、微波性能和可焊性),并与镀金板以及未做处理的基材对比,证明这2种材料不仅能替代镀金,而且涂覆后的铜表面耐蚀性优于镀金表面,电气性能和微波传输性未受影响,对环境更友好,且成本更低。

  2. Materials

    Science.gov (United States)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  3. Influencia de la temperatura de austenización y tiempo de permanencia sobre el tamaño de grano en aceros ferrítico-martensíticos del tipo 9Cr1MoVNb utilizados en calderas supercríticas

    Directory of Open Access Journals (Sweden)

    Gutiérrez-Urrutia, L.

    2001-04-01

    Full Text Available The aim of the present work is to determine the influence of austenitizing temperature holding time and heating velocity on grain size of ferritic-martensitic type 9CrlMoVNb steels developed for Oak Ridge National Laboratories & Combustion Engineering, T91/P91[1] Steels (USA and X10CrMoVNb 9.1 (Europe. The potential benefits of this material, in term of high resistance, good ductily and oxidation resistance, weldability and in particular good high temperature creep strength, are now widely acknowledged, particulary by supercritical boilers (P = 300 bar, T = 550±50 °C. The studied steels have been produced in, high frecuency induction vacum furnaces and hot-rolled.

    Se estudia la influencia de la temperatura de austenización, tiempo de permanencia a esta temperatura y velocidad de calentamiento sobre el tamaño de grano de varios aceros ferrítico-martensíticos de última generación del tipo 9CrlMoVNb, desarrollados por Oak Ridge National Laboratories (ORNL conjuntamente con Combustion Enginering en USA, conocidos por ASME/ASTM por las designaciones T91/P91[1] y en Europa como X10CrMoVNb9.1. Son aceros ductiles y tenaces que presentan muy buenas propiedades de resistencia a fluencia, soldabilidad y conductividad térmica. Son cada vez más utilizados como tubos de alta temperatura (550±50 °C y presión (300 bar en calderas supercríticas para centrales térmicas avanzadas. Los aceros estudiados se han fabricado en hornos de inducción de alta frecuencia al vacío y laminados en caliente.

  4. Influence of the nitrogen gas addition in the Ar shielding gas on the erosion-corrosion of tube-to-tube sheet welds of hyper duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hye-Jin; Jeon, Soon-Hyeok; Kim, Soon-Tae; Lee, In-Sung; Park, Yong-Soo [Yonsei University, Seoul (Korea, Republic of)

    2014-03-15

    Duplex stainless steels with nearly equal fraction of the ferrite(α) phase and austenite(γ) phase have been increasingly used for various applications such as power plants, desalination facilities due to their high resistance to corrosion, good weldability, and excellent mechanical properties. Hyper duplex stainless steel (HDSS) is defined as the future duplex stainless steel with a pitting resistance equivalent (PRE= wt.%Cr+3.3(wt.%Mo+0.5wt.%W)+30wt.%N) of above 50. However, when HDSS is welded with gas tungsten arc (GTA), incorporation of nitrogen in the Ar shielding gas are very important because the volume fraction of α-phase and γ-phase is changed and harmful secondary phases can be formed in the welded zone. In other words, the balance of corrosion resistance between two phases and reduction of Cr{sub 2}N are the key points of this study. The primary results of this study are as follows. The addition of N{sub 2} to the Ar shielding gas provides phase balance under weld-cooling conditions and increases the transformation temperature of the α-phase to γ-phase, increasing the fraction of γ-phase as well as decreasing the precipitation of Cr2N. In the anodic polarization test, the addition of nitrogen gas in the Ar shielding gas improved values of the electrochemical parameters, compared to the Pure Ar. Also, in the erosion-corrosion test, the HDSS welded with shielding gas containing N{sub 2} decreased the weight loss, compared to HDSS welded with the Ar pure gas. This result showed the resistance of erosion-corrosion was increased due to increasing the fraction of γ-phase and the stability of passive film according to the addition N{sub 2} gas to the Ar shielding gas. As a result, the addition of nitrogen gas to the shielding gas improved the resistance of erosion-corrosion.

  5. Hybrid Laser-arc Welding of 17-4 PH Martensitic Stainless Steel

    Science.gov (United States)

    Liu, Wei; Ma, Junjie; Atabaki, Mehdi Mazar; Pillai, Raju; Kumar, Biju; Vasudevan, Unnikrishnan; Sreshta, Harold; Kovacevic, Radovan

    2015-06-01

    17-4 PH stainless steel has wide applications in severe working conditions due to its combination of good corrosion resistance and high strength. The weldability of 17-4 PH stainless steel is challenging. In this work, hybrid laser-arc welding was developed to weld 17-4 PH stainless steel. This method was chosen based on its advantages, such as deep weld penetration, less filler materials, and high welding speed. The 17-4 PH stainless steel plates with a thickness of 19 mm were successfully welded in a single pass. During the hybrid welding, the 17-4 PH stainless steel was immensely susceptible to porosity and solidification cracking. The porosity was avoided by using nitrogen as the shielding gas. The nitrogen stabilized the keyhole and inhibited the formation of bubbles during welding. Solidification cracking easily occurred along the weld centerline at the root of the hybrid laser-arc welds. The microstructural evolution and the cracking susceptibility of 17-4 PH stainless steel were investigated to remove these centerline cracks. The results showed that the solidification mode of the material changed due to high cooling rate at the root of the weld. The rapid cooling rate caused the transformation from ferrite to austenite during the solidification stage. The solidification cracking was likely formed as a result of this cracking-susceptible microstructure and a high depth/width ratio that led to a high tensile stress concentration. Furthermore, the solidification cracking was prevented by preheating the base metal. It was found that the preheating slowed the cooling rate at the root of the weld, and the ferrite-to-austenite transformation during the solidification stage was suppressed. Delta ferrite formation was observed in the weld bead as well no solidification cracking occurred by optimizing the preheating temperature.

  6. Analysis of PTA hardfacing with CoCrWC and CoCrMoSi alloys

    Directory of Open Access Journals (Sweden)

    Adriano Scheid

    2013-12-01

    Full Text Available CoCrWC alloys are widely used to protect components that operate under wear and high temperature environments. Enhanced performance has been achieved with the CoCrMoSi alloys but processing this alloy system is still a challenge due to the presence of the brittle Laves phase, particularly when welding is involved. This work evaluated Plasma Transferred Arc coatings processed with the Co-based alloy CoMoCrSi - Tribaloy T400, reinforced with Laves phase, comparing its weldability to the CoCrWC - Stellite 6, reinforced with carbides. Coatings were also analyzed regarding the response to temperature exposure at 600°C for 7 days and subsequent effect on microstructure and sliding abrasive wear. Coatings characterization was carried out by light and scanning electron microscopy, X-ray diffraction and Vickers hardness. CoCrWC coatings exhibited a Cobalt solid solution dendritic microstructure and a thin interdendritic region with eutectic carbides, while CoCrMoSi deposits exhibit a large lamellar eutectic region of Laves phase and Cobalt solid solution and a small fraction of primary Laves phase. Although phase stability was observed by X-ray diffraction, coarsening of the microstructure occurred for both alloys. CoCrMoSi showed thicker lamellar Laves phase and CoCrWC coarser eutectic carbides. Coatings stability assessed by wear tests revealed that although the wear rate of the as-deposited CoCrMoSi alloy was lower than that of CoCrWC alloy its increase after temperature exposure was more significant, 22% against 15%. Results were discussed regarding the protection of industrial components in particular, bearings in 55AlZn hot dip galvanizing components.

  7. Hardness analysis of welded joints of austenitic and duplex stainless steels

    Science.gov (United States)

    Topolska, S.

    2016-08-01

    Stainless steels are widely used in the modern world. The continuous increase in the use of stainless steels is caused by getting greater requirements relating the corrosion resistance of all types of devices. The main property of these steels is the ability to overlap a passive layer of an oxide on their surface. This layer causes that they become resistant to oxidation. One of types of corrosion-resistant steels is ferritic-austenitic steel of the duplex type, which has good strength properties. It is easily formable and weldable as well as resistant to erosion and abrasive wear. It has a low susceptibility to stress-corrosion cracking, to stress corrosion, to intercrystalline one, to pitting one and to crevice one. For these reasons they are used, among others, in the construction of devices and facilities designed for chemicals transportation and for petroleum and natural gas extraction. The paper presents the results which shows that the particular specimens of the ][joint representing both heat affected zones (from the side of the 2205 steel and the 316L one) and the weld are characterized by higher hardness values than in the case of the same specimens for the 2Y joint. Probably this is caused by machining of edges of the sections of metal sheets before the welding process, which came to better mixing of native materials and the filler metal. After submerged arc welding the 2205 steel still retains the diphase, austenitic-ferritic structure and the 316L steel retains the austenitic structure with sparse bands of ferrite σ.

  8. Use Of Dynamic Resistance And Dynamic Energy To Compare Two Resistance Spot Welding Equipments For Automotive Industry In Zinc Coated And Uncoated Sheets.

    Directory of Open Access Journals (Sweden)

    Márcio Batista

    2013-01-01

    Full Text Available Resistance spot welding is a fabrication process highly used in the structures assembly. This fact evidences the importance of this welding process control, due to its efficiency, productivity speediness and straightforward simple automation. This work aimed to study the weldability of zinc coated and uncoated steel sheets for automotive industry, comparing the performance of two welding equipments with two current outputkinds: alternating current (AC and medium frequency direct current (DC. The welding parameters were kept constant: 260 kgf (force, 150 ms (time and 7.0 kA (welding current, based upon an optimization parameters methodology. The joints were characterized using optical metallography (spot diameter, indentation depth and weld penetration depth, mechanical tensile-shear tests and electrical measurements: contact electrical resistance, dynamic resistance and dynamic energy. The results showed that welding in medium frequency direct current was more efficient in generating heat in zinc coated sheets and uncoated sheets than alternating current equipment. In welding using AC and DC equipments in zinc coated sheets, the spot weld time formation was 25ms longer than uncoated steel sheets spot weld time. The burn of zinc during welding did not damage the spot weld formation with AC or DC equipments. The electrical contact resistance increased with the roughnessand also presented 52% higher in uncoated sheets than in zinc coated sheets. Finally, the increase in dynamicresistance and dynamic energy augmented the spot weld diameter for both welding equipments. As a final conclusion, the medium frequency direct current equipment presented better results than wave alternating current

  9. Large-stroke and high-strength actuator materials for adaptive structures

    Science.gov (United States)

    Ullakko, Kari

    1996-04-01

    The most important actuator materials in adaptive structures are shape memory alloys, piezoelectric and magnetostrictive materials and electrorheological fluids. However, no such material is available which would produce rapid and large strokes with high forces. Shape memory alloys exhibit large strokes and forces but their response is slow. Piezoelectric materials and magnetostrictive intermetallics are rapid, but the strokes are small. In the present study, employment of magnetic control of shape memory effect as a principle for rapid large stroke actuator materials is discussed. In such materials, detwinning is controlled by an external magnetic field. Twins in favorable orientation to the magnetic field grow at the expense of other twins and cause a shape change of the actuator. Strokes can be as high as those in shape memory alloys, but response times are short due to magnetic control. Another method which may be applied in actuators is inducing the martensitic transformation and controlling the growth of the martensite plates by magnetostrictive distortions of giant magnetostrictive particles embedded in the shape memory alloy matrix. Magnetostrictive inclusions can also be used as stress sensors in shape memory materials. In pre-stressing and fastening applications, materials which exhibit large strokes and high recovery stresses are required. Nitrogen alloyed shape memory steels, developed for actuators for those applications, is the second topic of this study. In nitrogen alloyed shape memory steels, yield strengths over 1100 MPa and tensile strengths even 1600 MPa were attained. Recoverable strains can be over 4% and recovery stresses 330 MPa. Stresses over 700 MPa were achieved in fasteners at room temperature. Nitrogen alloyed shape memory steels possess good corrosion properties, machinability and weldability (even the welds exhibit shape memory effect). They are economical to manufacture and use and they are expected to have applications in many

  10. The effect of single and double quenching heat treatments on the mechanical properties of low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeongpil; Kim, Byung Jun; Lee, Sanghui; Jang, Jaeho; Nam, Daegeun [Korea Institute of Industrial Technology, Busan (Korea, Republic of); Sung, Gichan [Sehwa M and P Co., LTD, Ulsan (Korea, Republic of)

    2014-05-15

    Dry cask storage is a method of storing high-level radioactive waste, such as spent nuclear fuel that has already been cooled in the spent fuel pool for at least one year. For spent fuel storage, low alloy steel is widely used for shielding materials for dry storage cask of spent fuel because of their excellent mechanical properties, weldability and low price. However, they may suffer embrittlement by high levels of radiation and heat for a long period. Therefore, it is important to improve mechanical properties of low alloy steel for the integrity of structure materials. Generally, conventional single quenching and tempering (CQT) heat treatment process is used to improve the mechanical properties by controlling the temperature and time of heat treatment. In this study, the microstructure and mechanical properties of DQT heat treated specimens were investigated to improve the mechanical properties of low alloy steels comparing the CQT heat treated specimen. The following conclusions were obtained. The grain size of DQT process has a fine average grain size comparing the CQT process. A fine grain structure with DQT specimen affects the mechanical properties such as the reduction of hardness and increments of elongation. The DBTT after DQT process is shifted to lower temperatures. Especially, the DBTT of steel-3 is shifted to lower temperature about -40 .deg. C comparing the CQT specimen(Steel-1). The reason for the reduction of DBTT and USE after the DQT process is related to the changes of microstructure which are transformed from bainite to pearlite phase and the reduction of grain size with decreasing the temperature of heat treatment.

  11. Development of Welding and Instrumentation Technology for Nuclear Fuel Test Rod

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang Young; Ahn, Sung Ho; Heo, Sung Ho; Hong, Jin Tae; Kim, Ka Hye [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    It is necessary to develop various types of welding, instrumentation and helium gas filling techniques that can conduct TIG spot welding exactly at a pin-hole of the end-cap on the nuclear fuel rod to fill up helium gas. The welding process is one of the most important among the instrumentation processes of the nuclear fuel test rod. To manufacture the nuclear fuel test rod, a precision welding system needs to be fabricated to develop various welding technologies of the fuel test rod jointing the various sensors and end-caps on a fuel cladding tube, which is charged with fuel pellets and component parts. We therefore designed and fabricated an orbital TIG welding system and a laser welding system. This paper describes not only some experiment results from weld tests for the parts of a nuclear fuel test rod, but also the contents for the instrumentation process of the dummy fuel test rod installed with the C-type T. C. A dummy nuclear fuel test rod was successfully fabricated with the welding and instrumentation technologies acquired with various tests. In the test results, the round welding has shown a good weldability at both the orbital TIG welding system and the fiber laser welding system. The spot welding to fill up helium gas has shown a good welding performance at a welding current of 30A, welding time of 0.4 sec and gap of 1 mm in a helium gas atmosphere. The soundness of the nuclear fuel test rod sealed by a mechanical sealing method was confirmed by helium leak tests and microstructural analyses.

  12. 3D printing of high-strength aluminium alloys.

    Science.gov (United States)

    Martin, John H; Yahata, Brennan D; Hundley, Jacob M; Mayer, Justin A; Schaedler, Tobias A; Pollock, Tresa M

    2017-09-20

    Metal-based additive manufacturing, or three-dimensional (3D) printing, is a potentially disruptive technology across multiple industries, including the aerospace, biomedical and automotive industries. Building up metal components layer by layer increases design freedom and manufacturing flexibility, thereby enabling complex geometries, increased product customization and shorter time to market, while eliminating traditional economy-of-scale constraints. However, currently only a few alloys, the most relevant being AlSi10Mg, TiAl6V4, CoCr and Inconel 718, can be reliably printed; the vast majority of the more than 5,500 alloys in use today cannot be additively manufactured because the melting and solidification dynamics during the printing process lead to intolerable microstructures with large columnar grains and periodic cracks. Here we demonstrate that these issues can be resolved by introducing nanoparticles of nucleants that control solidification during additive manufacturing. We selected the nucleants on the basis of crystallographic information and assembled them onto 7075 and 6061 series aluminium alloy powders. After functionalization with the nucleants, we found that these high-strength aluminium alloys, which were previously incompatible with additive manufacturing, could be processed successfully using selective laser melting. Crack-free, equiaxed (that is, with grains roughly equal in length, width and height), fine-grained microstructures were achieved, resulting in material strengths comparable to that of wrought material. Our approach to metal-based additive manufacturing is applicable to a wide range of alloys and can be implemented using a range of additive machines. It thus provides a foundation for broad industrial applicability, including where electron-beam melting or directed-energy-deposition techniques are used instead of selective laser melting, and will enable additive manufacturing of other alloy systems, such as non-weldable nickel

  13. Reparación por soldadura de rotores de turbinas de vapor y de gas fabricados con aceros al Cr-Mo-V

    Directory of Open Access Journals (Sweden)

    Mazur, Z.

    1999-04-01

    Full Text Available An analysis of typical steam turbine and gas turbine rotor failures is carried out. On the base of the rotors different failure causes and their mode of occurring, an evaluation of the weldability of the Cr-Mo-V steels and the classification of the common turbine rotors repair possibilities is presented. The developing of specific in-situ welding repair process of the damaged 20.65 MW gas turbine rotor is described. After repair, the rotor was put back into service.

    Se presenta un análisis de daños típicos en rotores de turbinas de vapor y de gas fabricados con aceros de baja aleación al Cr-Mo-V. Partiendo de las causas y modos de presentación de los fallos y el deterioro del material de los rotores durante la operación de la turbina, se lleva a cabo un análisis de la soldabilidad de los aceros al Cr-Mo-V y se presenta una clasificación de los posibles tipos de reparaciones de los rotores de turbinas. Con base en los daños presentados en el rotor de la turbina de gas de 20,65 MW, se presenta el desarrollo de la tecnología de reparación por soldadura llevada a cabo in situ. El rotor fue puesto nuevamente en servicio después del proceso de reparación.

  14. Duplex Stainless Steels-An overview

    Directory of Open Access Journals (Sweden)

    Dr. Sunil D.Kahar

    2017-04-01

    Full Text Available Stainless steel is one of the most important materials in the engineering world. The material‟s wide applications in chemical, petrochemical, off-shore, and power generation plants prove that it is one of the most reliable materials. The Newest fast growing family of stainless steels is duplex alloys. The ferritic-austenitic grades have a ferrite matrix intermix with austenite and in other words island of austenite in a continuous matrix of highly alloyed ferrite commonly called „Duplex‟ stainless steel. Duplex stainless steel covers ferritic/austenitic Fe-Cr-Ni alloy with between 30% to 70 % Ferrite .Due to high level of Cr, Mo, and N steels shows high pitting & stress corrosion cracking resistance in chloride-containing environments. Hence it is frequently used in oilrefinery heat exchangers & typical applications where there is a risk for SCC and localized corrosion as a result of chloride-containing process streams, cooling waters or deposits. Modern duplex stainless steels have generally good Weldability. Due to a balanced composition, where nitrogen plays an important role, austenite formation in the heat affected zone (HAZ and weld metal is rapid. Under normal welding conditions a sufficient amount of austenite is formed to maintain good resistance to localized corrosion where as too rapid cooling may result in excessive amounts of ferrite, reducing the toughness. Therefore, welding with low heat input in thick walled materials should be avoided. Welding methods, such as resistance welding, laser welding and electron beam welding, which cause extremely rapid cooling should also be avoided or used with extreme caution. Too slow cooling can in the higher alloyed duplex grades cause formation of inter-metallic phases detrimental to corrosion resistance and toughness.

  15. Technological experiment research of superplastic welding of 1.6C%-UHCS/40Cr with preset interlayer%预置中间层的1.6C-UHCS/40Cr超塑性焊接工艺试验

    Institute of Scientific and Technical Information of China (English)

    衡中皓; 张柯柯; 邱然锋; 涂益民; 乔騻; 李臣阳

    2012-01-01

    The experiments without vacuum or protection atmosphere was conducted based on the optimized design of superplastic welding of 1.6C%-UHCS/40Cr with preset interlayer. The results showed that choosing rolled industrial pure iron as an interlayer could improve the 1.6C%-UHCS/40Cr interface's plastic deformation and their weldability effectively. When the initial pressure was 56.6 MPa, welding temperature was 750 XI, initial strain rate was 1.5x10- 4s-1, after 10 min welding, the joint tensile strength could reach 702 MPa, which was 35% larger than without interlayer and equal with the tensile strength of 40Cr base metal after thermodynamic cycle.%基于对预置中间层的1.6C-UHCS/40Cr超塑性焊接工艺方案的优化设计,在非真空及无保护气氛下,进行了超塑性焊接工艺试验.试验结果表明:选用轧制态工业纯铁中间层,能有效改善1.6C-UHCS/40Cr超塑焊界面区的塑性变形能力,提高焊接性.在预压应力56.6 MPa、焊接温度750℃、初始应变速率1.5×10-4/s的条件下,经10 min压接,接头抗拉强度为702 MPa,比不加中间层的接头强度提高35%,达相同热力循环下40Cr母材的抗拉强度.

  16. Joining of Dissimilar alloy Sheets (Al 6063&AISI 304 during Resistance Spot Welding Process: A Feasibility Study for Automotive industry

    Directory of Open Access Journals (Sweden)

    Reddy Sreenivasulu

    2014-12-01

    Full Text Available Present design trends in automotive manufacture have shifted emphasis to alternative lightweight materials in order to achieve higher fuel efficiency and to bring down vehicle emission. Although some other joining techniques are more and more being used, spot welding still remains the primary joining method in automobile manufacturing so far. Spot welds for automotive applications should have a sufficiently large diameter, so that nugget pullout mode is the dominant failure mode. Interfacial mode is unacceptable due to its low load carrying and energy absorption capability. Strength tests with different static loading were performed in, to reveal the failure mechanisms for the lap-shear geometry and the cross-tension geometry. Based on the literature survey performed, venture into this work was amply motivated by the fact that a little research work has been conducted to joining of dissimilar materials like non ferrous to ferrous. Most of the research works concentrated on joining of different materials like steel to steel or aluminium alloy to aluminium alloy by resistance spot welding. In this work, an experimental study on the resistance spot weldability of aluminium alloy (Al 6063 and austenitic stainless steel (AISI304 sheets, which are lap joined by using a pedestal type resistance spot welding machine. Welding was conducted using a 45-deg truncated cone copper electrode with 10-mm face diameter. The weld nugget diameter, force estimation under lap shear test and T – peel test were investigated using digital type tensometer attached with capacitive displacement transducer (Mikrotech, Bangalore, Model: METM2000ER1. The results shows that joining of Al 6063 and AISI 304 thin sheets by RSW method are feasible for automotive structural joints where the loads are below 1000N act on them, it is observed that by increasing the spots per unit length, then the joint with standing strength to oppose failure is also increased linearly incase of

  17. X80高Nb管线钢组织与性能分析%Analysis on Microstructure and Mechanical Properties of High-niobium Microalloyed X80 Pipeline Steel

    Institute of Scientific and Technical Information of China (English)

    严春妍; 黄健成; 田松亚; 白世武

    2013-01-01

    总结回顾了X80高Nb管线钢的研究和发展,对其冶金设计、化学成分、显微组织结构、各项力学性能以及应力腐蚀行为、焊接性等进行了分析,并讨论了X80高Nb管线钢在应用中需要进一步研究的几个技术问题.通过低C高Nb合金化设计,可获得细小的针状铁素体组织,保证材料成分的同时具有很高的强度和良好的韧性.高温轧制技术(high temperature processing,HTP)的采用,不仅满足X80管线钢的技术条件要求,而且可以显著降低生产成本,有利于实现石油天然气更加高效经济的输送.%Research and development status of high-niobium microalloyed X80 pipeline steel were summarized and reviewed.Metallurgical design,microstructures,mechanical properties,stress corrosion behavior and field weldability were analyzed,and several applicative technological problems requiring further study and exploration were discussed.A low carbon-high niobium alloy design is used to produce a refined acicular ferrite microstructure which provides a combination of high strength and excellent toughness.The employment of high temperature processing(HTP) enables an excellent combination of key material performance characteristics satisfying relative specifications for X80 pipeline steel.Moreover,the HTP design allows for a significant reduction of total cost to realize the economical and efficient transmission of oil and gas.

  18. Analysis of features of stainless steels in dissimilar welded joints in chloride inducted corrosion

    Science.gov (United States)

    Topolska, S.; Łabanowski, J.

    2017-08-01

    Stainless steels of femtic-austenitic microstructure that means the duplex Cr-Ni-Mo steels, in comparison with austenitic steel includes less expensive nickel and has much better mechanical properties with good formability and corrosion resistance, even in environments containing chloride ions. Similar share of high chromium ferrite and austenite, which is characterized by high ductility, determines that the duplex steels have good crack resistance at temperatures up to approximately -40°C. The steels containing approximately 22% Cr, 5% Ni, 3% Mo and 0.2% N crystallizes as a solid solution δ, partially transforming from the temperature of about 1200°C to 850°C into the phase α. The stable structure of considered steels, at temperatures above 850°C, is ferrite, and at lower temperatures the mixture of phase γ+α +σ. The two-phase structure α+γ the duplex steel obtains after hyperquenching at the temperature of stability of the mixture of α+γ phases, and the share of the phases depends on the hyper quenching attributes. Hyperquenching in water, with a temperature close to 1200°C, ensures the instance in the microstructure of the steel a large share of ferrite and a small share of the high chromium austenite. This causes the increase of strength properties and reducing the plasticity of the steel and its resistance ability to cracking and corrosion. Slower cooling from the mentioned temperature, for example in the air, enables the partial transformation of the a phase into the γ one (α → γ) and increasing the share of austenite in the steel structure. It leads to improvement of plasticity properties. In the paper are presented the results of investigations of heteronymous welded joints of duplex steel and austenitic one. The results include the relation between the chemical composition of steels and their weldability.

  19. ABSTRACTS WELDEL PIPE AND TUBE

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    pipe sizes normal production within Ф114-Ф325mm. Subject Terms:Pipe production line turbine driving gear-box Su Shutian (51) Analysis of the Standing Spiral Loop and Uncoiler Interlock This article introduces the interlock method of standing spiral loop and uncoiler in the modern auto cold bend-- welded pipe production line. It gives out the concept of end inspection and surplus detection, and solves a problem for realizing the whole line automatization. Subject Terms:electric welded pipe standing loop uncoiler interlock Zhang Fuxing(53) A New Kind of Pipe Wall Thickness Measure This article introduces a new kind of pipe wall thickness inspection measure---electric digital display wall thickness callipers, And points out its properties, advantage, main technical parameters as well as the application method. Through the actual inspection, it is find that the precision of this kind of callipers meet the national standard requirement of GB/T14899-1994 for electric digital display callipers. Subject Terms:wall thickness callipers pipe measurer Cao change compiler(55) Weldable 13% Chromium Line Pipe by High Power Laser Welding NKK has developed weldable 13% chromium line pipe by applying the high power laser welding process(NKK-HPLW). This laser welded pipe realizes thinner alloy line pipe which is commonly designed in flow line usage. Tensile properties of this developed laser welded alloy pipe show equivalent revel of API-X80 grade.On toughness and corrosion resistance, weld area test results show the same revel of base metal. It is confirmed that good characteristics as same as base metal are obtained by NKK-HPLW. And high power laser welded 13% chromium pipe will become an advantageous material for CO2 corrosive field development. Subject Terms:pipe line stainless pipe thin pipe weldability laser welding toughness corrosion resistance

  20. 节能型钢筋、线材的研发与生产实践%Development and practice of energy saving steel reinforcing bar and wire

    Institute of Scientific and Technical Information of China (English)

    麻晗; 王世芳

    2013-01-01

    The latest R&D outcomes on long products including rebar,high carbon steel,cold heading steel,and tire cord steel were introduced.The following achievements are highlighted,600 MPa grade hot rolled rebar exhibites even microstructure and better weldability,which meets the requirements for aseismatic rebar; anti-corrosion rebar shows an extraordinary corrosion resistance in sea water,whose erosion life is longer than that of conventional rebar by over 70% in neutral salt fog environment; S87A high carbon low-alloyed wire rod is with the average tensile strength up to 1420 MPa,the highest value in known industrial wire rods; 10B21 boron-bearing cold heading steel could omit the spheroidizing annealing before drawing,which is perfect for fastener with severe deformation; non-heat-treatment cold heading steel displays the energy saving character by omitting the quenching and high tempering process after forming.%介绍了节能型长材螺纹钢筋、高碳钢、冷镦钢、帘线钢等的最新研发成果.600 MPa级热轧螺纹钢筋具有组织均匀、可焊性好等优点,满足抗震钢筋的要求;耐蚀钢筋具备优良的耐海水腐蚀能力,在中性盐雾环境中的腐蚀寿命比普通螺纹钢筋高70%以上;S87A高碳合金钢盘条的平均抗拉强度为1420MPa,是已知强度最高的工业化盘条;10B21含硼冷镦钢可省略拉拔前的球化退火,特别适合制作大变形量的紧固件;非调质冷镦钢可省略成型后的调质处理,具有显著的节能特征.

  1. 汽车排气系统用超纯铁素体不锈钢的焊接%Welding of Ultra-pure Ferrite Stainless Steel for Automotive Exhaust System

    Institute of Scientific and Technical Information of China (English)

    薛春霞; 朱云龙

    2012-01-01

    分析了超纯铁素体不锈钢的焊接性,概括了汽车排气系统不锈钢管常用的焊接方法和焊接工艺.分析认为,超纯铁素体不锈钢焊接时的主要问题是焊接接头易产生晶间腐蚀和脆化,用超纯铁素体不锈钢制造汽车排气管,需要选择能量集中、热输入小、保护效果好的焊接方法和焊接参数.主要焊接方法有钨极氩弧焊、激光焊、高频焊和等离子弧焊.此外,组合焊接技术尤其是激光与其他热源复合加热的铁素体不锈钢管焊接研究等,是汽车排气管先进焊接方法的发展方向.%In this article, the weldability of ultra-pure ferrite stainless steel was analyzed, the welding methods and technologies which were commonly used on the stainless steel pipes for automotive exhaust system were summarized. The results indicated that the main problems which appear in welding of ultra-pure ferrite stainless steel are the intercrystalline corrosion and embrittlement in the welded joints. It should select some welding methods and welding parameters with the characteristics of energy concentration, low-heat input and good protective effect, such as argon tungsten arc welding, laser welding, high frequency welding and plasma arc welding to produce automotive exhaust system using ultra-pure ferrite stainless steel. In addition, the composite welding technologies are the developing direction of advanced welding methods used for automotive exhaust pipes, especially for the research on compound heating welding ferrite stainless steel pipes by laser and other heat sources.

  2. 1Cr5Mo珠光体耐热钢管的三种不同工艺研究%Research in three different welding technology of 1Cr5Mo pearlitic heat-resistant steel pipe

    Institute of Scientific and Technical Information of China (English)

    赵亮; 李宪臣; 刘海河

    2011-01-01

    Describes the three different welding technologies of applied to the steel currently by analyzing the weldability of Cr5Mo steel.It can be proposed that welding with the same materials as much as possible in order to avoid joints early failure in the operation and reduce welding cost when it has the availability of post weld heat treatment conditions and case of large-scale welding by comparing the performance differences of welded joints obtained and the implementation features with the three welding technology.If in the absence of heat treatment conditions or less maintenance in the field.it is also can be welded with different materials. However,we recommend using the new low-Cr high manganese AR617 weld rod to weld Cr5Mo so as to ensure that it will not low ductile fracture in the joints, the weld rod has excellent welding technology .Through joints sampling observation in the production practices and 44 000 hours service,performance is stable,fully meet the production requirements,the welding technology conditions is relatively simple.%通过分析1Cr5Mo钢的焊接性,介绍了当前应用于该钢种的三种不同的焊接工艺方法.通过比较三种焊接工艺方法所获得焊接接头性能差异和特点,提出在具备焊后热处理条件和大规模施焊情况下应尽可能采用同质材料进行焊接,以避免接头在运行中出现早期失效,降低焊接成本.在不具备热处理条件或现场维修量少的情况下,也可采用异质材料进行焊接.但是,为保证接头在长期高温运行下不出现低韧性脆性断裂,建议采用新型低铬高锰型AR617焊条焊接1Cr5Mo,该焊条焊接工艺性能优良,通过生产实践和对服役44000 h的接头取样观察,使用性能稳定,完全满足生产要求,其焊接工艺条件相对简单.

  3. Effect of minor Sc on microstructure and mechanical properties of Al–Zn–Mg–Zr alloy metal–inert gas welds

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xing [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Pan, Qinglin, E-mail: pql1964@126.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Bo [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiming; Huang, Zhiqi [Guangdong Fenglu Aluminium Co., Ltd, Foshan 528133 (China); Yin, Zhimin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2015-04-25

    Highlights: • The MIG weld-ability of Al–Zn–Mg–Sc–Zr sheet is evaluated. • Effect of Sc on microstructure and mechanical properties is investigated. • Width of EQZ increases with increasing of Sc content at the fusion boundary. • Grain refinement and properties improvement are attributed to Sc additions. - Abstract: 2.5 mm thick cold-rolled Al–Zn–Mg–Zr alloy plates with trace amount of Sc were subjected to metal–inert gas (MIG) welding with Al–Mg–Sc as the filler metal. The influence of Sc additions on microstructure and mechanical properties of the welded joints was investigated by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Vickers micro-hardness test and room temperature tensile test. Experimental results indicated that trace amount of Sc had significant effect on microstructure and mechanical properties of the joints. In both cases, base metal consisted of a typical fiber structure, different width of the equiaxed zones (EQZs) with fine grains were observed in the weld metal at the fusion boundary, fusion zones exhibited dendritic microstructure and average size of Al–Zn–Mg–0.10%Sc–Zr was 120 μm, while in Al–Zn–Mg–0.25%Sc–Zr, grain size decreased drastically to 50 μm. The grain refinement is mainly caused by the extremely fine, coherent Al{sub 3}(Sc, Zr) particles with L1{sub 2} structure, which act as heterogeneous nucleation. The observed grain refinement resulted in an appreciable increase in fusion zone strength and micro-hardness. Tensile strength of Al–Zn–Mg–0.25Sc–Zr alloy welded joint was 460 MPa, approximately 11% higher than Al–Zn–Mg–0.10Sc–Zr alloy welded joint. Micro-hardness in the center of fusion zone rose from 95 HV to 110 HV. The main strengthening mechanisms of Al–Zn–Mg–Sc–Zr MIG welded joints are precipitation strengthening derived from η′ precipitates, dispersion

  4. EB-welding of the copper canister for the nuclear waste disposal. Final report of the development programme 1994-1997

    Energy Technology Data Exchange (ETDEWEB)

    Aalto, H. [Outokumpu Oy Poricopper, Pori (Finland)

    1998-10-01

    During 1994-1997 Posiva Oy and Outokumpu Poricopper Oy had a joint project Development of EB-welding method for massive copper canister manufacturing. The project was part of the national technology program `Weld 2000` and it was supported financially by Technology Development Centre (TEKES). The spent fuel from Finnish nuclear reactors is planned to be encapsulated in thick-walled copper canisters and placed deep into the bedrock. The thick copper layer of the canister provides a long time corrosion resistance and prevents deposited nuclear fuel from contact with water. The quality requirements of the copper components are high because of the designed long lifetime of the canister. The EB-welding technology has proved to be applicable method for the production of the copper canisters and the EB-welding technique is needed at least when the lids of the copper canister will be closed. There are a number of parameters in EB-welding which affect weldability. However, the effect of the welding parameters and their optimization has not been extensively studied in welding of thick copper sections using conventional high vacuum EB-welding. One aim of this development work was to extensively study effect of welding parameters on weld quality. The final objective was to minimise welding defects in the main weld and optimize slope out procedure in thick copper EB-welding. Welding of 50 mm thick copper sections was optimized using vertical and horizontal EB-welding techniques. As a result two full scale copper lids were welded to a short cylinder successfully. The resulting weld quality with optimised welding parameters was reasonable good. The optimised welding parameters for horizontal and vertical beam can be applied to the longitudinal body welds of the canister. The optimal slope out procedure for the lid closure needs some additional development work. In addition of extensive EB-welding program ultrasonic inspection and creep strength of the weld were studied. According

  5. 国内汽车板的生产现状及对生产装备的需求%Domestic Current Status of Automobile Sheets and Demand on Production Equipment

    Institute of Scientific and Technical Information of China (English)

    黄彦峰; 范文斌; 孙立峰

    2014-01-01

    汽车板作为制造汽车用主要材料,应具备很好的刚性、成形性、耐蚀性、焊接性等特点。如今,消费者对汽车在安全、节能、耐用、外观等方面有了更高的要求,这其中,为了减重节能而大量采用高强度钢板和高强度变截面板,以及为提高耐蚀性而大量采用镀锌钢板等已成为汽车板今后发展的主要方向。与此相适应,用于生产汽车板的轧机生产线应具备更高的性能以适应生产高强钢的需要,而镀锌机组不但应具备生产高强度镀锌板的能力,而且应尽早实现电镀锌机组的国产化。%As a main material to build automobiles, the automobile sheet shall have high stiffness, formability, corrosion resistance and weldability. Today, customers have stricter requirement on the safety, energy-saving, service durability and appearance of automobiles. High-strength steel plates and high-strength variable cross-section steel plates used in a large amount to reduce the weight of automobiles and galvanized steel plates used in large amount to increase the corrosion resistance are main tendency of future automobile sheet development. For this purpose, the rolling mill to produce automobile sheets shall have suitable capacity to produce high-strength steel plates. The galvanizing plate mill shall not only have the capacity to produce high-strength galvanized plates but also be built independently by the builders in China.

  6. High nitrogen steels for internal combustion engines. Final report; Druckaufgestickte Staehle fuer Verbrennungsmotore. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Horn, H.; Knuth, L.U.

    1998-07-01

    The aim of the study was the investigation of the weldability of martensitic and austenitic high nitrogen steels (HNS) in the case of valve applications. Friction welding and surfacing with the plasma-transferred arc hardfacing process is necessary for these applications. Because friction welding is a welding process in the range of the upper forging temperature and a melting zone during the welding does not take place, the nitrogen content in the base alloy is not affected. Therefore, friction welds with good properties can be produced. During the plasma process the HNS were remelted with the effect of a decreasing nitrogen content and formation of pores in the surfacing layer. Surfacing with a mixed argon-nitrogen gas with a nitrogen content more than 40% leads to porefree weldments. On the other hand, the stability of the plasma arc and the durability of the tungsten electrode decreases rapidly. Alloying of the HNS with nitrogen-affined elements like Niob a.o. is conductive to get porefree weldments also with nitrogen poor (ca 5%) plasma gas. In this case the welding process is in a controlled and reproducible condition and the hardness of the surface layer is in accordance with the requirements. (orig.) [German] In dem Forschungsvorhaben wurde die Schweisseignung von druckaufgestickten austenitischen und martensitischen Staehlen fuer den Einsatz als Ventilwerkstoffe untersucht. Bestimmend fuer diesen Einsatzfall sind das Plasma-Pulver-Auftragschweissen und das Reibschweissen. Die Reibschweisseignung der genannten Staehle ist sowohl untereinander als auch mit konventionellen Ventilstaehlen gegeben. Bei dem Plasma-Pulver-Auftragschweissen werden die druckaufgestickten Grundwerkstoffe verfahrensbedingt wieder aufgeschmolzen. Dies fuehrt zum Austreten des zwangsgeloesten Stickstoffes und damit zur unzulaessigen Porenbildung in der Auftragschweissung. Durch die Zugabe von Stickstoff zu dem Plasmagas kann die Porenbildung deutlich reduziert und mit Stickstoffgehalten

  7. Micro-resistance Welding Technology and Its Application to Interconnection of Radar T/R Module%微电阻焊及其在雷达 T/R 组件互连中的应用

    Institute of Scientific and Technical Information of China (English)

    霍绍新; 解启林

    2015-01-01

    The micro-resistance welding technology is widely used in the manufacturing of electronics and me-chanical equipment for it′s mature and simple and convenient to operate.In this paper this technology is inno-vatively applied to the interconnection of the microwave modules such as the T/R module.The process and method of the micro-resistance welding in the microwave multichip modules are first analyzed.Then by means of this process the interconnection can be realized between the low-frequency connectors and its metal sub-strate, between different microwave circuits or the inner circuits on the RF connector joint.This process and technology can overcome the rigorous limits of surface weldability.The results show that the welding qualities of the metal wire and ribbon ( the copper wire plated with gold, gold ribbon and copper foil plated with gold) in the high frequency and RF circuits are reliable.%微电阻焊技术成熟且操作简便,被广泛应用于电子及机械制造领域。文中将其创新性地应用到了雷达T/R组件微波模块的内部互连中。文中首先分析了微波组件中电阻焊的实现工艺与方法,然后应用该技术分别实现了T/R组件的低频连接器与基板之间、射频电路模块之间以及高频连接器接头内部电路的互连。利用该工艺技术方法,可以突破常规引线键合时焊接面可焊性要求较高的限制,可以实现高频、射频电路中金属丝、带(如镀金铜丝、金带、镀金铜箔)的互连。初步验证表明,其焊接质量良好。

  8. The Development and Production of a Functionally Graded Composite for Pb-Bi Service

    Energy Technology Data Exchange (ETDEWEB)

    Ballinger, Ronald G

    2011-08-01

    A material that resists lead-bismuth eutectic (LBE) attack and retains its strength at 700°C would be an enabling technology for LBE-cooled reactors. No single alloy currently exists that can economically meet the required performance criteria of high strength and corrosion resistance. A Functionally Graded Composite (FGC) was developed with layers engineered to perform these functions. F91 was chosen as the structural layer of the composite for its strength and radiation resistance. Fe-12Cr-2Si, an alloy developed from previous work in the Fe-Cr-Si system, was chosen as the corrosion-resistant cladding layer because of its chemical similarity to F91 and its superior corrosion resistance in both oxidizing and reducing environments. Fe-12Cr-2Si experienced minimal corrosion due to its self-passivation in oxidizing and reducing environments. Extrapolated corrosion rates are below one micron per year at 700ï°C. Corrosion of F91 was faster, but predictable and manageable. Diffusion studies showed that 17 microns of the cladding layer will be diffusionally diluted during the three year life of fuel cladding. 33 microns must be accounted for during the sixty year life of coolant piping. 5 cm coolant piping and 6.35 mm fuel cladding preforms were produced on a commercial scale by weld-overlaying Fe-12Cr-2Si onto F91 billets and co-extruding them. An ASME certified weld was performed followed by the prescribed quench-and-tempering heat treatment for F91. A minimal heat affected zone was observed, demonstrating field weldability. Finally, corrosion tests were performed on the fabricated FGC at 700ï°C after completely breaching the cladding in a small area to induce galvanic corrosion at the interface. None was observed. This FGC has significant impacts on LBE reactor design. The increases in outlet temperature and coolant velocity allow a large increase in power density, leading to either a smaller core for the same power rating or more power output for the same size

  9. High-Temperature Extensometry and PdCr Temperature-Compensated Wire Resistance Strain Gages Compared

    Science.gov (United States)

    1997-01-01

    A detailed experimental evaluation is underway at the NASA Lewis Research Center to compare and contrast the performance of the PdCr/Pt dual-element temperature-compensated wire resistance strain gage with that of conventional high-temperature extensometry. The advanced PdCr gage, developed by researchers at Lewis, exhibits desirable properties and a relatively small and repeatable apparent strain to 800 C. This gage represents a significant advance in technology because existing commercial resistance strain gages are not reliable for quasi-static strain measurements above approx. 400 C. Various thermal and mechanical loading spectra are being applied by a high-temperature thermomechanical uniaxial testing system to evaluate the two strain-measurement systems. This is being done not only to compare and contrast the two strain sensors, but also to investigate the applicability of the PdCr strain gage to the coupon-level specimen testing environment typically employed when the high-temperature mechanical behavior of structural materials is characterized. Strain measurement capabilities to 800 C are being investigated with a nickel-base superalloy, Inconel 100 (IN 100), substrate material and application to TMC's is being examined with the model system, SCS-6/Ti-15-3. Furthermore, two gage application techniques are being investigated in the comparison study: namely, flame-sprayed and spot welding. The apparent strain responses of both the weldable and flame-sprayed PdCr wire strain gages were found to be cyclically repeatable on both IN 100 and SCS-6/Ti-15-3 [0]_8. In general, each gage exhibited some uniqueness with respect to apparent strain behavior. Gages mounted on the IN 100 specimens tended to show a repeatable apparent strain within the first few cycles, because the thermal response of IN 100 was stable. This was not the case, however, for the TMC specimens, which typically required several thermal cycles to stabilize the thermal strain response. Thus

  10. Study the microstructure of three and four component phases in Al-Ni-Fe-La alloys

    KAUST Repository

    Kolobylina, Natalia

    2016-12-21

    Aluminium alloys play a key role in modern engineering since they are the most used non-ferrous material. They have been widely used in automotive, aerospace, and construction engineering due to their good corrosion resistance, superior mechanical properties along with good machinability, weldability, and relatively low cost. The progress in practical application has been determined by intensive research and development works on the Al alloys. A new class of Al–REM–TM aluminum alloys (REM indicates rare earth metal and TM is transition metal) was revealed in the end of the last century. These alloys differ from conventional ones by their extraordinary ability to form metal glasses and nanoscale composites in a wide range of compositions. Having low density, these alloys possess unique mechanical characteristics and corrosion resistance. Two as received alloys, namely Al85Ni9Fe2La4 and Al85Ni7Fe4La4 were obtained in the form of ingots from melts of corresponding compositions upon cooling in air were studied by scanning/transmission electron microscopy (STEM), energy dispersive X-ray (EDX) microanalysis and X-ray diffraction (XRD). The microstructural analyses were performed in a aberration corrected TITAN 80-300 TEM/STEM (FEI, USA) attached with EDX spectrometer with ultrathin window (EDAX, USA). The specimens for transmission electron microscopy (TEM) were prepared by an electrochemical or ion etching. It was found that the received alloys exhibits along with fcc Al and Al4La (Al11La3) particles, these alloys contain a ternary phase Al3Ni1 Fe isostructural to the Al3Ni phase and a quaternary phase Al8Fe2 NiLa isostructural to the Al8Fe2Eu phase and monoclinic phase Al9(Fe,Ni)2 isostructural to the Al9Co2. The study by HRSTEM together with a new atomic resolution energy dispersive X-ray microanalysis method demonstrated that Fe and Ni atoms substituted one another in the Al8Fe2–NiLa quaternary compound. Besides, several types of defects were determined: first

  11. Improvement of bonding properties of laser transmission welded, dissimilar thermoplastics by plasma surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hopmann, Ch.; Weber, M.; Schöngart, M.; Sooriyapiragasam, S.; Behm, H.; Dahlmann, R. [Institute of Plastics Processing (IKV), RWTH Aachen University, Pontstrasse 49, 52062 Aachen (Germany)

    2015-05-22

    Compared to different welding methods such as ultrasonic welding, laser transmission welding is a relatively new technology to join thermoplastic parts. The most significant advantages over other methods are the contactless energy input which can be controlled very precisely and the low mechanical loads on the welded parts. Therefore, laser transmission welding is used in various areas of application, for example in medical technology or for assembling headlights in the automotive sector. However, there are several challenges in welding dissimilar thermoplastics. This may be due to different melting points on the one hand and different polarities on the other hand. So far these problems are faced with the intermediate layer technique. In this process a layer bonding together the two components is placed between the components. This means that an additional step in the production is needed to apply the extra layer. To avoid this additional step, different ways of joining dissimilar thermoplastics are investigated. In this regard, the improvement in the weldability of the dissimilar thermoplastics polyamide 6 (PA 6) and polypropylene (PP) by means of plasma surface modification and contour welding is examined. To evaluate the influence of the plasma surface modification process on the subsequent welding process of the two dissimilar materials, the treatment time as well as the storage time between treatment and welding are varied. The treatment time in pulsed micro wave excited oxygen plasmas with an electron density of about 1x10{sup 17} m{sup −3} is varied from 0.5 s to 120 s and the time between treatment and welding is varied from a few minutes up to a week. As reference, parts being made of the same polymer (PP and PA 6) are welded and tested. For the evaluation of the results of the welding experiments, short-time tensile tests are used to determine the bond strength. Without plasma treatment the described combination of PA 6/PP cannot be welded with

  12. Effect of gold thickness on ENIG PCB solder spread and joint reliability%金层厚度对沉金PCB焊锡延展性及焊点可靠性的影响

    Institute of Scientific and Technical Information of China (English)

    李伏; 李斌

    2015-01-01

    通过锡球延展性、常规可焊性、黑盘和焊盘拉脱强度测试验证了金层厚度对沉金(ENIG)印刷电路板(PCB)焊锡延展性的影响,并用扫描电镜评估了金属间化合物(IMC)。结果表明,金层越厚,焊锡延展性越好。但金层只起保护镍层的作用,沉金 PCB焊点的可靠性建立在IMC基础上,只要能在镍层与焊料之间能形成良好的金属间化合物,即可保证焊点的可靠性。另外,金层越厚,黑盘的风险越高,且有可能引起金脆问题,因此不能一味地追求沉金层的厚度以提高焊锡延展性。%The effect of gold thickness on solder spread of electroless nickel/immersion gold (ENIG) printed circuit board (PCB) was verified through solder ball spread test, normal weldability test, black pad test, and pad pull strength test. The intermetallic compounds (IMCs) were assessed by scanning electron microscope. The results showed that the solder spread gets better with increasing thickness of gold layer. However, gold layer is only used to protect the nickel layer. The reliability of solder joint is built on the basis of IMCs, and can be guaranteed as long as good IMC can be formed between nickel layer and solder. The thicker the gold layer, the higher risk of black pad will be, and gold embrittlement problem may be caused. The thickness of immersion gold should not be blindly pursued for improving the solder ductility.

  13. Study on High Strength Low Alloy Bainitic Steel Rails%低合金高强度贝氏体钢轨的试验研究

    Institute of Scientific and Technical Information of China (English)

    陈朝阳; 周清跃; 张银花; 刘丰收; 陈昕

    2013-01-01

    根据我国铁路技术装备发展的需要,开展低合金高强度贝氏体钢轨的实验室研究及工业性试制、显微组织及性能试验研究、焊接性能及铺设使用研究.结果表明:贝氏体钢轨具有优良的强韧性配合,室温抗拉强度达到1 240 MPa,断后伸长率15.3%,平均冲击功达到142 J,-20℃断裂韧性KIC为48 MPa.m1/2;钢轨全断面显微组织为无碳化物贝氏体;焊接性能研究结果表明:贝氏体钢轨具有良好的焊接性,其接触焊、气压焊和铝热焊接头的各项性能均达到我国铁路钢轨的铺设使用要求.试铺结果表明:贝氏体钢轨的耐磨性能与高强度热处理钢轨相当,抗接触疲劳伤损性能突出,综合使用性能优于珠光体型热处理钢轨及热轧钢轨.%To meet the dramatic growth needs of China railways,the systematic research work of bainitic steel rails was conducted,including laboratory study,trial production,microstruture and properties study and welding performance,laying & operation study.The results show as follows:At room temperature,the average tensile strength,tensile elongation and CUN impact toughness of rail cross section reach respectively 1240 MPa,15.3% and 142 J;the fracture toughness (KIC) at-20 ℃ was up to 48 MPa · m1/2 ; the microstructure of the whole rail section is carbon-free bainite;the bainitic rails possess good weldability,their performance with flash butt welding,gas pressure welding and thermit welding all satisfy requirements of laying and operation of rails of China railways;the bainitic rails have better spalling resistance and wear resistance than rolled and heat hardened pearlitic rails so that they provide better comprehensive operating characteristics.

  14. Process analysis and simulation of the processing methods for fiber reinforced thermoplastic semi-finished tape products; Prozessanalyse und -simulation von Verarbeitungsverfahren fuer faserverstaerkte thermoplastische Baendchenhalbzeuge

    Energy Technology Data Exchange (ETDEWEB)

    Latrille, M.

    2003-07-01

    The aerospace industry and the off-shore oil industry are facing the introduction and evolution of fiber reinforced thermoplastics. Performance enhancements as well as cost and weight savings are the drivers behind this development. The high level of requirements concerning the quality of components leads to a need for applicable manufacturing technologies. Filament winding and tape placement are examples for such processes. Both have been successfully industrialized for thermoset materials. Thermoset components for high temperature or primary structure applications are typically manufactured in a multi-step approach. After a geometry determining step consolidation and curing are introduced as further processing steps towards the final component, often using ovens or autoclaves. Being weldable, thermoplastics give the possibility to integrate these multi-step thermoset processes. Hence the complexity of thermoplastic processing is increased, but the potential of saving manufacturing time is obvious. This leads to the need of theoretic background know how about the physical, thermodynamical and chemical phenomena behind the thermoplastic manufacturing technologies. Due to that, since many years worldwide efforts are carried out concerning the understanding, abstraction and simulation of these processes. But, the developed models hardly have a direct relation to real processes. The present work overcomes the gap between simulation and experimental process development. Based on a widely used mathematical description of the thermodynamics within the processes, an energy balance equation, which is enhanced with radiative boundary conditions for the first time in this context, the present work describes the development of a process simulation tool. The newly developed finite-element program ProSimFRT, which is based on a non-linear discretization of the energy balance equation, serves as kernel of a modular process simulation environment. This package allows the

  15. The effect of retentive groove, sandblasting and cement type on the retentive strength of stainless steel crowns in primary second molars - An in vitro comparative study

    Directory of Open Access Journals (Sweden)

    M M Veerabadhran

    2012-01-01

    Full Text Available Purpose: This in vitro study was conducted to find out the effect of retentive groove, sand blasting and cement type on the retentive strength of stainless steel crowns in primary second molars. Materials and Methods: Thirty-two extracted intact human maxillary and mandibular primary second molars were embedded in aluminum blocks utilizing autopolymerising acrylic resin. After tooth preparation, the 3M stainless steel crown was adjusted to the prepared tooth. Then weldable buccal tubes were welded on the buccal and lingual surfaces of each crown as an attachment for the testing machine. A full factorial design matrix for four factors (retentive groove placement on the tooth, cement type, sandblasting and primary second molar at two levels each was developed and the study was conducted as dictated by the matrix. The lower and upper limits for each factor were without and with retentive groove placement on the tooth, GIC and RMGIC, without and with sandblasting of crown, maxillary and mandibular second primary molar. For those teeth for which the design matrix dictated groove placement, the retentive groove was placed on the middle third of the buccal surface of the tooth horizontally and for those crowns for which sandblasting of the crowns are to be done, sandblasting was done with aluminium oxide with a particle size of 250 mm. The crowns were luted with either GIC or RMGIC, as dictated by the design matrix. Then the retentive strength of each sample was evaluated by means of an universal testing machine. The obtained data was analyzed using ANOVA for statistical analysis of the data and ′t′- tests for pairwise comparison. Results: The mean retentive strength in kg/cm 2 stainless steel crowns luted with RMGIC was 19.361 and the mean retentive strength of stainless steel crowns luted with GIC was 15.964 kg/cm 2 with a mean difference of 3.397 kg/cm 2 and was statistically significant. The mean retentive strength in kg/cm 2 of stainless steel

  16. On the Possibility of using Alluminium-Magnesium Alloys with Improved Mechanical Characteristics for Body Elements of Zenit-2S Launch Vehicle Propellant Tanks

    Science.gov (United States)

    Sitalo, V.; Lytvyshko, T.

    2002-01-01

    Yuzhnoye SDO developed several generations of launch vehicles and spacecraft that are characterized by weight perfection, optimal cost, accuracy of output geometrical characteristics, stable strength characteristics, high tightness. The main structural material of launch vehicles are thermally welded non-strengthened aluminium- magnesium alloys. The aluminium-magnesium alloys in the annealed state have insufficiently high strength characteristics. Considerable increase of yield strength of sheets and plates can be reached by cold working but in this case, plasticity reduces. An effective way to improve strength of aluminium-magnesium alloys is their alloying with scandium. The alloying with scandium leads to modification of the structure of ingots (size reduction of cast grain) and formation of supersaturated solid solutions of scandium and aluminium during crystallization. During subsequent heatings (annealing of the ingots, heating for deformation) the solid solution disintegrates with the formation of disperse particles of Al3Sc type, that cause great strengthening of the alloy. High degree of dispersion and density of distribution in the matrix of secondary Al3Sc particles contribute to the considerable increase of the temperature of recrystallization of deformed intermediate products and to the formation of stable non-recrystallized structure. The alloying of alluminium-magnesium alloys with scandium increases their strength and operational characteristics, preserves their technological and corrosion properties, improves weldability. The alloys can be used within the temperature limits ­196-/+150 0C. The experimental structures of propellant tanks made of alluminium-magnesium alloys with scandium have been manufactured and tested. It was ascertained that the propellant tanks have higher margin of safety during loading with internal pressure and higher stability factor of the shrouds during loading with axial compression force which is caused by higher value

  17. Influencia de la técnica de soldadura multipasada y de los tratamientos térmicos de precalentamiento y post-soldadura en el comportamiento de uniones GMAW de un aceromicroaleado HARDOX 400

    Directory of Open Access Journals (Sweden)

    Manjabacas, M. C.

    2011-02-01

    Full Text Available The microalloyed steels may be supplied in a hardened state. In these cases, the weldability can be improved by pre-heat and/or post-heat welding treatments. In this paper, the effect of those treatments and the influence of multipass welding on GMAW joints behavior are analyzed for a Hardox 400 microalloyed steel. The microstructure evaluation of the different heat affected zones of the steel has been made and the mechanical properties of those zones are obtained for different conditions as it has been mentioned. The obtained results indicate that preheating the steel leads to a beneficial action that consists on the distance increasing from the bead to the zone in which the hardness is lowest. The postheat treatment strengthens that zone and improves the joint plasticity. This benefit is higher if the joint has been made with preheating. Multipass welding has not been found to have any advantage if it is compared to a single welding pass.

    Los aceros microaleados pueden suministrarse endurecidos. En estos casos, aunque el acero sea soldable, puede dar lugar a índices de soldabilidad que pueden ser mejorables con tratamientos térmicos de precalentamiento y/o tratamientos post-soldeo. En el presente trabajo se analiza el efecto del precalentamiento, soldeo multipasada y postcalentamiento en uniones GMAW del acero HARDOX 400. Se realizan análisis macro y microestructurales de las zonas características de la unión y del comportamiento mecánico de la misma en función de las variables indicadas. Los resultados obtenidos indican el efecto beneficioso del precalentamiento debido al alejamiento de la zona de menor dureza en la ZAT respecto al borde del cordón. También se demuestra que el precalentamiento aumenta el índice de heterogeneidad de la unión, lo que mejora su comportamiento a fatiga, tal y como demuestran algunos autores. El tratamiento térmico postsoldeo también presenta un efecto beneficioso ya que refuerza ligeramente la

  18. Development and Application of A New Generation High Strength-plasticity Steels%新一代高强塑性钢的开发与应用

    Institute of Scientific and Technical Information of China (English)

    李光瀛; 周积智

    2011-01-01

    为满足汽车、建筑、能源等工业对材料强度级别和使用性能不断提高的要求,世界钢铁业正在开发新一代高强塑性钢.基于先进高强度钢AHSS汽车板、高强度抗震建筑用钢和高等级管线钢的开发,讨论了新一代高强塑性钢的主要技术特征,包括使用性能(成形性、抗冲撞能力、抗震性能、抗皱能力、超载下的形变能力)对塑性指标(均匀延伸率、n值、屈强比)的要求、复相组织与残余奥氏体的强塑化机理、关键工艺技术以及新产品新技术的发展方向.同时考虑到对强韧性和焊接性能的要求,讨论了热变形奥氏体动力学模型、高韧性焊接热影响区HAZ的细化韧化以及硫含量的影响与控制.%To meet the increasing requirement of automotive, construction and energy industry on high strength and high performance of structural materials, a new generation of high strength-plasticity (HSP) steels has been developed by the steel industry in the world.Based on the development of advanced high strength steels AHSS, high strength steels for construction and high grade pipeline steels, the main features of HSP steels are discussed, including the requirement of performance (formability, crashworthiness, aseismic ability, buckling resistance and deformability) on plasticity index (uniform elongation, n-value, yield ratio), the strengtheningplasticizing mechanism with multiphase structure and retained austenite, key process and technology as well as the promised new products and new techniques.For the necessary toughness and weldability, the dynamic model for austenite recrystallization, high toughness welding HAZ refinement and toughening and the effect of sulfur content are also discussed.

  19. Improvement in creep-rupture life of 1Cr1Mo(1)/(4)V steel castings and their weld joints by addition of niobium

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Kulvir; Jaipal Reddy, G.; Reddy, K.S. [Corporate R and D, BHEL, Hyderabad (India). Metallurgy Dept.

    2008-07-01

    1Cr1Mo(1)/(4)V steel was cast with varying percentages of 0.04, 0.06 and 0.08% of niobium. The CrMoV cast steels having the above chemical composition, were subjected to a heat treatment by solutionising them to a temperature at 1040 C and subsequent cooling to room temperature, then, subjecting to a tempering at a temperature below the Ac1 point at 740 C. CrMoV electrodes were used for welding. Welding, as per the plant practices was carried out on the castings and weldability studies were conducted. Base metal and weld joint samples were subjected to hardness, impact, tensile, hot tensile and creep/ stress rupture testing. Creep/ stress rupture testing was carried out at 525, 550, 575 and 600 C and stresses varying from 100 - 300 MPa. Microstructural analysis including scanning and transmission electron microscopy was carried out on the as received as well as tested material. Room and high temperature tensile strength of 1Cr1Mo(1)/(4)V steel with Nb addition was higher than plain 1Cr1Mo(1)/(4)V steel. Among Nb added steels, creep-rupture and tensile strength of 0.06 and 0.08%Nb steel was found to be highest. The creep ductility of these casts is slightly lower than plain 1Cr1Mo(1)/(4)V steel but the cast with 0.08% Nb showed highest creep-rupture ductility. On the basis of creep-rupture test results on weld joint samples, the weld joints of steel with 0.08%Nb are found to be stronger than plain 1Cr1Mo(1)/(4)V steel as well as with 0.04 and 0.06%Nb. Creep-rupture ductility and impact strength of weld as well as HAZ region of 0.08% Nb steel were highest. 1Cr1Mo(1)/(4)V cast steel with Nb addition is envisaged to be used for steam turbine casing castings and valve castings. If turbine casings and valve castings are made of Nb containing steels, it is possible to increase the steam temperature and pressure and also the efficiency and reliability of the turbine. Substantial gains in terms of cost and life improvement can be made. (orig.)

  20. EB-welding of the copper canister for the nuclear waste disposal. Final report of the development programme 1994-1997

    Energy Technology Data Exchange (ETDEWEB)

    Aalto, H. [Outokumpu Oy Poricopper, Pori (Finland)

    1998-10-01

    During 1994-1997 Posiva Oy and Outokumpu Poricopper Oy had a joint project Development of EB-welding method for massive copper canister manufacturing. The project was part of the national technology program `Weld 2000` and it was supported financially by Technology Development Centre (TEKES). The spent fuel from Finnish nuclear reactors is planned to be encapsulated in thick-walled copper canisters and placed deep into the bedrock. The thick copper layer of the canister provides a long time corrosion resistance and prevents deposited nuclear fuel from contact with water. The quality requirements of the copper components are high because of the designed long lifetime of the canister. The EB-welding technology has proved to be applicable method for the production of the copper canisters and the EB-welding technique is needed at least when the lids of the copper canister will be closed. There are a number of parameters in EB-welding which affect weldability. However, the effect of the welding parameters and their optimization has not been extensively studied in welding of thick copper sections using conventional high vacuum EB-welding. One aim of this development work was to extensively study effect of welding parameters on weld quality. The final objective was to minimise welding defects in the main weld and optimize slope out procedure in thick copper EB-welding. Welding of 50 mm thick copper sections was optimized using vertical and horizontal EB-welding techniques. As a result two full scale copper lids were welded to a short cylinder successfully. The resulting weld quality with optimised welding parameters was reasonable good. The optimised welding parameters for horizontal and vertical beam can be applied to the longitudinal body welds of the canister. The optimal slope out procedure for the lid closure needs some additional development work. In addition of extensive EB-welding program ultrasonic inspection and creep strength of the weld were studied. According

  1. Cracking susceptibility of duplex stainless steel in the presence of H{sub 2}S-containing environments at an intermediate temperature

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado, Julio G.; Kane, Russell D. [InterCorr International, Inc., 14503 Bammel N. Houston, Suite 300, Houston, Texas 77014 (United States); Skogsberg, James W. [ChevronTexaco, 4800 Fournace Pl, Bellaire, Texas 77401 (United States)

    2004-07-01

    The use of duplex stainless steels in the oil and gas industry has received special consideration due to their good corrosion resistance, mechanical properties and weldability. Specifically, duplex stainless steels possess excellent chloride pitting resistance and stress corrosion cracking resistance. In this study, the cracking susceptibility of duplex stainless steel at 80 deg. C in the presence of H{sub 2}S containing environments was investigated. Specifically, environments containing 1,000 ppm and 100,000 ppm Cl- brines with a pH of 3 and 4.5, respectively, and with H{sub 2}S partial pressures of 1.5, 5 and 10 psia (10, 34 and 69 kPa abs) were employed for the evaluation. The cracking susceptibility of the duplex stainless steel material was only evaluated with respect to the solution-annealed condition. For the experimental work, sub-size tensile specimens of annealed 2205 duplex (UNS S31803/S32205) stainless steel under a sustained load, with the use of proving rings, were tested in triplicate with exposure durations of up to 90 days. Cyclic polarization scans were also conducted for each of the environments selected for the cracking susceptibility study. The electrochemical work was conducted to ascertain the differences in the breakdown potential, hence, pitting potential and resulting cracking susceptibility of the material under the environmental conditions evaluated. The results of this work indicated that duplex stainless steel in the solution-annealed condition was resistant to sulfide stress cracking up to a partial pressure of H{sub 2}S of 5 psia (34 kPa abs). Only one specimen in each of the two Cl-/pH combined conditions with an applied H{sub 2}S partial pressure of 10 psia (69 kPa abs) failed during the 90-day exposure. These results suggest a possible extension on the applicability of the material in terms of the maximum allowed H{sub 2}S partial pressure in the NACE MR0175 document. (authors)

  2. Welding state of art for Eurofer 97 application to Tritium Blanket Module for ITER Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, P. [CEA Saclay, Dept. Modelisation de Systemes et Structures (DEN/DANS/DM2S/DIR), 91 - Gif sur Yvette (France); Janin, F. [CEA Saclay, Dept. Modelisation de Systemes et Structures (DEN/DANS/DPC/SCP/Gerailp), 91 - Gif sur Yvette (France)

    2007-07-01

    Full text of publication follows: Eurofer weldability must be established for data base assessment and TBM manufacturing support. Electron Beam, Hybrid (Laser combined with MIG/MAG), Laser and Narrow Gap TIG processes have been carried out on Eurofer samples from 0.5 mm to 40 mm. Electron Beam produces very narrow fusion zone width, in the range of 3 to 4 mm, that yields brittle joints with (5-ferrite. This process is considered only for low penetration depth (cooling plates). The other processes produce similar results, with attenuation or enhanced effects, depending on cooling rates and weld penetration depth. Pre- and post-heating have been applied on hybrid and laser welds. High hardness values, increasing brittleness and softening effects in the Heat Affected Zone are observed for each welding configuration that could signal creep problems. The Fusion Zones are typically composed of martensite laths, with small grain sizes. In the Heat Affected Zones, martensite grains are observed with M23C6 carbide precipitation. Delta ferrite has been observed only in Electron Beam welds, due to very high cooling rate during the solidification phase, related to strong enhanced weld shape. Eurofer filler wire with optimized chemical composition is developed for producing welds with good properties. To restore properties after welding, PWHT seems is necessary and several treatments including one at 750 deg. C for 2 hours have been performed. Also tries is a re-austenisation treatment of 10 h at 1050 deg. C. affecting order to improve results, pre- and post-heating has been applied. The heating produced by the resistive heater was too low, and new welding tests are planned at higher temperatures (400 deg. C). However, the pre- and post-heating at higher temperatures will complicate manufacturing of TBM clamping For penetration depths below 10 mm, laser process is the reference method and TIG second. Distortion level performed by laser process is acceptable for manufacturing

  3. Evaluations of Mo-alloy for light water reactor fuel cladding to enhance accident tolerance

    Directory of Open Access Journals (Sweden)

    Cheng Bo

    2016-01-01

    Full Text Available Molybdenum based alloy is selected as a candidate to enhance tolerance of fuel to severe loss of coolant accidents due to its high melting temperature of ∼2600 °C and ability to maintain sufficient mechanical strength at temperatures exceeding 1200 °C. An outer layer of either a Zr-alloy or Al-containing stainless steel is designed to provide corrosion resistance under normal operation and oxidation resistance in steam exceeding 1000 °C for 24 hours under severe loss of coolant accidents. Due to its higher neutron absorption cross-sections, the Mo-alloy cladding is designed to be less than half the thickness of the current Zr-alloy cladding. A feasibility study has been undertaken to demonstrate (1 fabricability of long, thin wall Mo-alloy tubes, (2 formability of a protective outer coating, (3 weldability of Mo tube to endcaps, (4 corrosion resistance in autoclaves with simulated LWR coolant, (5 oxidation resistance to steam at 1000–1500 °C, and (6 sufficient axial and diametral strength and ductility. High purity Mo as well as Mo + La2O3 ODS alloy have been successfully fabricated into ∼2-meter long tubes for the feasibility study. Preliminary results are encouraging, and hence rodlets with Mo-alloy cladding containing fuel pellets have been under preparation for irradiation at the Advanced Test Reactor (ATR in Idaho National Laboratory. Additional efforts are underway to enhance the Mo cladding mechanical properties via process optimization. Oxidation tests to temperatures up to 1500 °C, and burst and creep tests up to 1000 °C are also underway. In addition, some Mo disks in close contact with UO2 from a previous irradiation program (to >100 GWd/MTU at the Halden Reactor have been subjected to post-irradiation examination to evaluate the chemical compatibility of Mo with irradiated UO2 and fission products. This paper will provide an update on results from the feasibility study and discuss the attributes of the

  4. Phenomena Elucidation of High Brightness Fiber Laser Welding of Stainless Steel

    Science.gov (United States)

    Kawahito, Yousuke; Mizutani, Masami; Katayama, Seiji

    A high-brigthness fiber laser can produce an ultra-high peak power density of MW/mm2 level corresponding to a focused electron beam, and is promising as one of the desirable heat sources for deep-penetration welding. The objectives of this research are to elucidate the factors affecting weld penetration and defects formation mechanisms, to obtain a fundamental knowledge of interaction between a fiber laser beam and the laser-induced plume, and to assess laser absorption with water-calorimetric method in bead-on-plate welding of Type 304 austenitic stainless steel plates with a 10 kW fiber laser beam. Concerning the weldablity and defects, the penetration depth reached 18 mm at the maximum. At 50 mm/s or lower welding speeds, porosity was generated under the conventionally-focused and tightly-focused conditions. X-ray transmission in-site observation images demonstrated that pores were formed not only at the tip of the keyhole but also near the upper part. The keyhole behavior was stabilized by using nitrogen shielding gas, which led to the porosity prevention. As for the interaction under the normal Ar shielding gas conditions, the temperature and ionization degree of the laser-induced plumes were calculated to be 6,000 K and 0.02, respectively, by the Bolzman plots and Saha's equation. It was also found that the attenuation and the refraction between the 10-kW fiber laser beam and the short weakly-ionized plume were too small to exert the reduction in weld penetration. The laser absorption of the stainless steel plate was approximately 85 % high at 10 kW laser power and 50 mm/s welding speed. Compared X-ray transmission observation images of the keyhole with the focusing feature of the fiber laser beam, most of the incident laser passed through the keyhole inlet, and the center part of the beam was delivered directly to the tip of the deep keyhole. Consequently, as far as the adquate welding procedures were utilized on the basis of eclucidation of the welding

  5. Avaliação da soldagem multipasse de chapas espessas de aços inoxidáveis lean duplex UNS S32304 soldadas pelos processos SMAW, GMAW e FCAW: parte 1: propriedades mecânicas Evaluation of multipass welding of thick lean duplex stainless steel UNS S32304 plates welded by SMAW, GMAW and FCAW: part 1: Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Ronaldo Cardoso Junior

    2012-12-01

    Full Text Available Os aços inoxidáveis duplex (AID vêm se apresentando como uma excelente alternativa para aplicações em que alta resistência à corrosão e alta resistência mecânica são requeridas. Contudo, os AID, incluindo os aços inoxidáveis lean duplex, apresentam soldabilidade inferior em relação aos aços inoxidáveis austeníticos. Nesse sentido, esse trabalho tem como objetivo a avaliação da soldagem multipasse de chapas 22 mm de espessura da liga inoxidável lean duplex UNS S32304, utilizando-se os processo SMAW, GMAW e FCAW e consumíveis com dois tipos de composição química, 22%Cr9%Ni3%Mo e 23%Cr7%Ni, totalizando seis experimentos. Foram empregados chanfros em V com 60º e suporte cerâmico para soldagem do passe de raiz, sendo que o aporte térmico foi mantido praticamente constante em 1,6 kJ.mm-1. Determinou-se os tempos de soldagem e a seqüência de passes, objetivando uma análise de produtividade, em seguida as juntas soldadas foram submetidas à END por raios x. Foram extraídos corpos de prova para ensaios de tração, dobramento, Charpy a -30 ºC e microdureza. A produtividade dos processos semi-automáticos se mostrou pelo menos 63 % maior que a do processo SMAW, enquanto o processo FCAW se mostrou de 6 a 18% mais rápido que o GMAW. Foram encontradas descontinuidades (porosidade consideradas aceitáveis segundo ASME B31.3 em alguns dos experimentos, que não influenciaram negativamente os resultados mecânicos, os quais se apresentaram acima requerimento do metal de base e especificado por normas de fabricação.The duplex stainless steels (DSS's have been placed as an excellent alternative for applications where high corrosion resistance and high mechanical strength are required. However, DSS's, including the lean duplex, present lower weldability than the austenitic stainless steels. Thus, this study aims to evaluate the multipass welding of 22 mm plates of lean duplex stainless steel alloy UNS S32304, using the process

  6. Solid State Joining of High Temperature Alloy Tubes for USC and Heat-Exchanger Systems

    Energy Technology Data Exchange (ETDEWEB)

    Bimal Kad

    2011-12-31

    The principal objective of this project was to develop materials enabling joining technologies for use in forward looking heat-exchanger fabrication in Brayton cycle HIPPS, IGCC, FutureGen concepts capable of operating at temperatures in excess of 1000{degree}C as well as conventional technology upgrades via Ultra Super-Critical (USC) Rankine-cycle boilers capable of operating at 760{degree}C (1400F)/38.5MPa (5500psi) steam, while still using coal as the principal fossil fuel. The underlying mission in Rankine, Brayton or Brayton-Rankine, or IGCC combined cycle heat engine is a steady quest to improving operating efficiency while mitigating global environmental concerns. There has been a progressive move to higher overall cycle efficiencies, and in the case of fossil fuels this has accelerated recently in part because of concerns about greenhouse gas emissions, notably CO{sub 2}. For a heat engine, the overall efficiency is closely related to the difference between the highest temperature in the cycle and the lowest temperature. In most cases, efficiency gains are prompted by an increase in the high temperature, and this in turn has led to increasing demands on the materials of construction used in the high temperature end of the systems. Our migration to new advanced Ni-base and Oxide Dispersion Strengthened (ODS) alloys poses significant fabrication challenges, as these materials are not readily weldable or the weld performs poorly in the high temperature creep regime. Thus the joining challenge is two-fold to a) devise appropriate joining methodologies for similar/dissimilar Ni-base and ODS alloys while b) preserving the near baseline creep performance in the welded region. Our program focus is on solid state joining of similar and dissimilar metals/alloys for heat exchanger components currently under consideration for the USC, HIPPS and IGCC power systems. The emphasis is to manipulate the joining methods and variables available to optimize joint creep

  7. Grain size control and superplasticity in 6013-type aluminum alloys

    Science.gov (United States)

    Troeger, Lillianne Plaster Whitelock

    Aluminum alloys have been the material of choice for aircraft construction since the 1930's. Currently, the automotive industry is also showing an increasing interest in aluminum alloys as structural materials. 6xxx aluminum alloys possess a combination of strength and formability which makes them attractive to both industries. In addition, 6xxx alloys are highly weldable, corrosion resistant, and low in cost as compared with the 2xxx and 7xxx aluminum alloys. Superplastic forming (SPF) is a manufacturing process which exploits the phenomenon of superplasticity in which gas pressure is used to form complex-shaped parts in a single forming operation. This reduces part counts and the need for fasteners and connectors, resulting in reduced product weight. Reduced product/vehicle weight improves fuel economy. Most alloys must be specially processed for superplasticity. Much research effort has been directed at the development of thermomechanical processes for the grain refinement of aluminum alloys by static or dynamic recrystallization. to induce superplasticity. While large numbers of studies have been conducted on 2xxx, 5xxx, 7xxx, and 8xxx aluminum alloys, very few studies have been focused on the grain refinement of 6xxx aluminum alloys for superplasticity. The current research describes a new thermomechanical process for application to 6xxx aluminum alloys for grain refinement and superplasticity. The process is shown to successfully refine and induce superplasticity in an Al-Mg-Si-Cu alloy which falls within the compositional limits of both 6013 and 6111. The grain refinement is by particle-stimulated nucleation of recrystallization. The microstructural evolution during the thermomechanical processing is characterized in terms of precipitate size, shape, distribution and composition; texture; recrystallization; and grain size, shape, and thermal stability. The new process produces a statically-stable, weakly-textured, equiaxed grain structure with an average

  8. Obtención y caracterización de materiales compuestos W-Cu para contactos eléctricos

    Directory of Open Access Journals (Sweden)

    Krivij, N.

    2003-08-01

    Full Text Available In the Cuban Metallurgical Research Center (CIME, are manufactured by powder metallurgy, shims of adjustment of a W-Cu composite material, that are used in the electrical contacts of the panels of control of the portico derricks that operate in the port of Havana City. The base material used has a composition of 70 % in mass electrolytic copper powder and wolfram powder of (30 % that is obtained by reduction from the oxide from wolfram. The powders are submitted to the stages of mixed, pressed and agglomeration and is obtained a composite material with free particles of W occluded in a counterfoil of Cu matrix, that do not interact and they provide the following properties: high melting temperature, high electro and thermo conductivity and corrosion resistance, high mechanical and electrical strengtheners, decrease weldability and stability during their development. However, when not reacting the volframio particles with the copper, the compound material will begin to fuse to the temperature of the copper, on the other hand and for the same reason the resistance to the corrosion should be similar to that of the pure copper. The shims of adjustment are fixed to the bodies of high purity copper welding with a silver alloy, the one which provides the maximum qualities of the Cu, as elasticity, breaking strength, thermal and electrical conductivities, as well corrosion resistance.

    En el Centro de Investigaciones Metalúrgicas (CIME, cubano, se fabrican por pulvimetalurgia, calzos de material compuesto volframio-cobre, que se utilizan en los contactos eléctricos de los paneles de control de las grúas pórtico que operan en el puerto de Ciudad de La Habana. El material base que se utiliza contiene un 70 % en masa de polvo de cobre electrolítico y polvo de volframio (30 %, que se obtiene por reducción del óxido de volframio. Los polvos se someten a las etapas de mezclado, prensado y sinterización obteniéndose un material compuesto con las

  9. PTA hardfacing of Nb/Al coatings Revestimentos Nb/Al depositados por PTA

    Directory of Open Access Journals (Sweden)

    Karin Graf

    2012-06-01

    Full Text Available Hardfacing is widely applied to components yet the majority of the welding techniques available restrain the variety of hard alloys that can be deposited. Plasma Transferred Arc hardfacing offsets this drawback by using powdered feedstock offering the ability to tailor the chemical composition of the coating and as a consequence its properties. The high strength and chemical inertia of aluminide alloys makes them very suitable to protect components. However, the strong interaction with the substrate during hardfacing requires analysis of each alloy system to optimize its properties and weldability. This work analyzed coatings processed with a cast and ground Nb40wt%Al alloy and the effect of Fe and C on the coatings features. It confirmed that sound Nb aluminide coatings can be processed by plasma Transferred arc hardfacing and will have a strong interaction with the substrate, which determines the final microstructure and properties of coatings. Final remarks point out that during Nb-Al coating tailoring the interaction with the substrate has to be considered at the early stages of design process.Revestimentos soldados são amplamente usados para proteger componentes mecânicos entretanto a maioria das técnicas de soldagem disponíveis restringe a variedade de ligas de alta resistência que podem ser depositadas. O processo de plasma por arco transferido permite ultrapassar esta limitação ao utilizar material de adição na forma de pó, oferecendo a possibilidade de se customizar a composição dos revestimentos e em consequências as suas propriedades. A elevada resistência mecânica e inercia química das ligas de aluminetos tornam estas ligas atrativas para a proteção de componentes diversos. Entretanto a grande interação com o substrato que ocorre quando do processamento exige que para a otimização das propriedades e soldabilidade seja realizada uma a análise de cada sistema liga e substrato. Neste trabalho foram processados e

  10. Niobium carbide and tin precipitation in continuously cast microalloyed steels

    Science.gov (United States)

    Stock, Julian

    With high yield strength, toughness and good weldability, microalloyed steels are widely used in the automotive, pipeline and transportation industries. Microalloying elements such as niobium (Nb), titanium (Ti) and vanadium (V) in concentrations of less than 0.1 wt. pct. are typical. For optimal benefits in the final product, it is usually desired for Ti to form fine precipitates during and after solidification and for Nb to be in solution prior to hot-rolling. Vanadium precipitates at lower temperatures and is less involved in the solidification/casting process. In one aspect of the investigation, the effects of cooling rate on the titanium nitride (TiN) precipitation size distribution were investigated in a Ti-added low-carbon steel. Prior research reported an inverse relationship between the average TiN precipitation size and the post-solidification cooling rate and the present work was undertaken to examine this behavior over a wider range of cooling rates. Using the GleebleRTM 3500's casting simulation capabilities along with controlled cooling rates, the TiN precipitation behavior in thick-slab, thin-slab and thin-strip material was simulated using a commercially produced 0.04C, 1.23Mn steel with near-stoichiometric Ti and N levels. Transmission electron microscopy (TEM) investigation of carbon extraction replicas was carried out to characterize the influence of cooling rates on precipitate size distributions. Decreasing particle sizes with increasing cooling rates were found. Average particle sizes as low as 6.7 nm were present in thin-strip simulations and might be of interest, as fine particles could contribute to strengthening of rapidly cooled steels. In a second aspect of the investigation, niobium carbide (NbC) precipitation during the compact strip production (CSP) process was investigated in two Nb-added low-carbon steels. Instead of industrial sampling, the GleebleRTM was used for casting simulations using two CMn(Nb) steels with high and low- Nb

  11. Estudo de viabilidade da soldagem de termoplásticos por "Friction Spot Welding" (FSpW Feasibility study of the Friction Spot Welding (FSpW process in thermoplastics

    Directory of Open Access Journals (Sweden)

    Pedro Henrique Freiria de Oliveira

    2012-06-01

    good processability, weldability, aging and chemical resistance. The welded samples were analyzed by optical microscopy and Vickers microhardness measurements and mechanically tested. Lap-shear testing showed ultimate shear resistance values of about 9,5 MPa, which were similar or higher than values obtained through current PMMA welding techniques, such as microwave welding, ultrasonic welding and thermal bonding. Therefore, the present work was able to demonstrate the potential of FSpW as an alternative welding process for thermoplastics.

  12. LENS repair and modification of metal NW components:materials and applications guide.

    Energy Technology Data Exchange (ETDEWEB)

    Smugeresky, John E. (Sandia National Laboratories, Livermore, CA); Gill, David Dennis; Oberhaus, Jason (BWXT Y-12); Adams, Thad (Savannah River National Laboratory); VanCamp, Chad (Kansas City Plant)

    2006-11-01

    Laser Engineered Net Shaping{trademark} (LENS{reg_sign}) is a unique, layer additive, metal manufacturing technique that offers the ability to create fully dense metal features and components directly from a computer solid model. LENS offers opportunities to repair and modify components by adding features to existing geometry, refilling holes, repairing weld lips, and many other potential applications. The material deposited has good mechanical properties with strengths typically slightly higher that wrought material due to grain refinement from a quickly cooling weld pool. The result is a material with properties similar to cold worked material, but without the loss in ductility traditionally seen with such treatments. Furthermore, 304L LENS material exhibits good corrosion resistance and hydrogen compatibility. This report gives a background of the LENS process including materials analysis addressing the requirements of a number of different applications. Suggestions are given to aid both the product engineer and the process engineer in the successful utilization of LENS for their applications. The results of testing on interface strength, machinability, weldability, corrosion resistance, geometric effects, heat treatment, and repair strategy testing are all included. Finally, the qualification of the LENS process is briefly discussed to give the user confidence in selecting LENS as the process of choice for high rigor applications. The testing showed LENS components to have capability in repair/modification applications requiring complex castings (W80-3 D-Bottle bracket), thin wall parts requiring metal to be rebuilt onto the part (W87 Firing Set Housing and Y-12 Test Rings), the filling of counterbores for use in reservoir reclamation welding (SRNL hydrogen compatibility study) and the repair of surface defects on pressure vessels (SRNL gas bottle repair). The material is machinable, as testing has shown that LENS deposited material machines similar to that of

  13. Fast-Response-Time Shape-Memory-Effect Foam Actuators

    Science.gov (United States)

    Jardine, Peter

    2010-01-01

    Bulk shape memory alloys, such as Nitinol or CuAlZn, display strong recovery forces undergoing a phase transformation after being strained in their martensitic state. These recovery forces are used for actuation. As the phase transformation is thermally driven, the response time of the actuation can be slow, as the heat must be passively inserted or removed from the alloy. Shape memory alloy TiNi torque tubes have been investigated for at least 20 years and have demonstrated high actuation forces [3,000 in.-lb (approximately equal to 340 N-m) torques] and are very lightweight. However, they are not easy to attach to existing structures. Adhesives will fail in shear at low-torque loads and the TiNi is not weldable, so that mechanical crimp fits have been generally used. These are not reliable, especially in vibratory environments. The TiNi is also slow to heat up, as it can only be heated indirectly using heater and cooling must be done passively. This has restricted their use to on-off actuators where cycle times of approximately one minute is acceptable. Self-propagating high-temperature synthesis (SHS) has been used in the past to make porous TiNi metal foams. Shape Change Technologies has been able to train SHS derived TiNi to exhibit the shape memory effect. As it is an open-celled material, fast response times were observed when the material was heated using hot and cold fluids. A methodology was developed to make the open-celled porous TiNi foams as a tube with integrated hexagonal ends, which then becomes a torsional actuator with fast response times. Under processing developed independently, researchers were able to verify torques of 84 in.-lb (approximately equal to 9.5 Nm) using an actuator weighing 1.3 oz (approximately equal to 37 g) with very fast (less than 1/16th of a second) initial response times when hot and cold fluids were used to facilitate heat transfer. Integrated structural connections were added as part of the net shape process, eliminating

  14. Research and development in welding and hardfacing towards construction of prototype fast breeder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Albert, S.K.; Bhaduri, A.K. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2012-07-01

    India's 500MWe Prototype Fast Breeder Reactor (PFBR) is in advanced stage of construction at Kalpakkam and this reactor is expected to be commissioned in the year 2013. Extensive research and development activities in various fields like material development, welding, forming, non-destructive testing etc. were undertaken before the actual construction of the reactor began. Many of these activities are still continuing with the objectives of conducting functional tests, generating data, validating the design and meeting the various regulatory requirements. In welding, initial challenge was to develop indigenous welding consumables with a specification more stringent than that is given in most of the national and international standards. The welding consumable specified for 316LN austenitic stainless steel is E316-15M with strict control on delta ferrite content, toughness requirement after 750 C/100 h ageing to ensure adequate resistance to embrittlement during prolonged high temperature exposure and good slag detachability. This consumable was successfully developed in collaboration with Indian consumable manufacturers and is being used for fabrication of almost all PFBR components and piping made of 316LN stainless steel. Similarly, electrodes of welding of modified 9Cr-1Mo steel (material of construction for PFBR steam generator) with requirement of RTNDT requirement of ≤ -5 C was also developed indigenously. Extensive studies were also carried out on weldability of various austenitic stainless steels and modified 9Cr-1Mo steel used in PFBR. Hot cracking susceptibility of alloy D9 (15Cr-15Ni-2Mo-Ti alloy), the material chosen for fuel clab tube and fuel sub-assembly, and 316LN stainless steel was extensively studied using varestraint testing and Gleeble simulation. Results from these steels were used in developing welding procedures for various reactor components. Hydrogen assisted cracking susceptibility (HAC) of modified 9Cr-1Mo steel was studied using

  15. Influence of composition on precipitation behavior and stress rupture properties in INCONEL RTM740 series superalloys

    Science.gov (United States)

    Casias, Andrea M.

    Increasing demands for energy efficiency and reduction in CO2 emissions have led to the development of advanced ultra-supercritical (AUSC) boilers. These boilers operate at temperatures of 760 °C and pressures of 35 MPa, providing efficiencies close to 50 pct. However, austenitic stainless steels typically used in boiler applications do not have sufficient creep or oxidation resistance. For this reason, nickel (Ni)-based superalloys, such as IN740, have been identified as potential materials for AUSC boiler tube components. However, IN740 is susceptible to heat-affected-zone liquation cracking in the base metal of heavy section weldments. To improve weldability, IN740H was developed. However, IN740H has lower stress rupture ductility compared to IN740. For this reason, two IN740H modifications have been produced by lowering carbon content and increasing boron content. In this study, IN740, IN740H, and the two modified IN740H alloys (modified 1 and 2) were produced with equiaxed grain sizes of 90 ìm (alloys IN740, IN740H, and IN740H modified 1 alloys) and 112 µm (IN740H modified 2 alloy). An aging study was performed at 800 °C on all alloys for 1, 3, 10, and 30 hours to assess precipitation behavior. Stress rupture tests were performed at 760 °C with the goal of attaining stress levels that would yield rupture at 1000 hours. The percent reduction in area was measured after failure as a measure of creep ductility. Light optical, scanning electron, and transmission electron microscopy were used in conjunction with X-ray diffraction to examine precipitation behavior of annealed, aged, and stress rupture tested samples. The amount and type of precipitation that occurred during aging prior to stress rupture testing or in-situ during stress rupture testing influenced damage development, stress rupture life, and ductility. In terms of stress rupture life, IN740H modified 2 performed the best followed by IN740H modified 1 and IN740, which performed similarly, and IN740

  16. Characterization of the hot cracking resistance using the Essential Work of Fracture (EWF: application to duplex stainless steels Caracterização da resistência ao trincamento a quente com base nos trabalhos esssenciais de mecânica da fratura: aplicação aos aços inoxidáveis duplex

    Directory of Open Access Journals (Sweden)

    Guilhem Martin

    2013-06-01

    Full Text Available Duplex stainless steels (DSS involve two ductile phases, i.e. ferrite and austenite, with a proportion of each phase around 50%. The main advantage in comparison with other austenitic and ferritic stainless steels is the excellent combination of high strength and corrosion resistance together with good formability and weldability. Unfortunately, DSS present in general a poor hot workability. Standard hot ductility tests like hot tensile or hot torsion tests are always helpful to compare the fracture resistance of two very ductile materials. A new method based on the essential work of fracture (EWF concept has been used in order to determine the hot cracking resistance. The EWF concept was introduced to address ductile fracture based on the entire load-displacement response up to the complete fracture of a specimen and not from the initiation measurements such as in classical fracture mechanics concepts. The aim of the method consists in separating, based on dimensional considerations, the work performed within the plastic zone from the total work of fracture in order to provide an estimate of the work spent per unit area within the fracture process zone to break the material. This method proved to be very well adapted to high temperature cracking. Two different duplex stainless steels have been characterized by the essential work of fracture method. Examination of the fracture micrographs and profiles match the EWF results. This method turns out to be a discriminating tool for quantifying hot cracking and to generate a physically relevant fracture index to guide the optimization of microstructures towards successful forming operations.Aços inoxidáveis duplex (AID envolvem duas fases dúcteis, isto é, ferrita e austenita, com uma proporção de cada fase de cerca de 50%. A principal vantagem, em comparação com outros austeníticos e aços inoxidáveis ferríticos, é a excelente combinação de alta resistência mecânica e resistência

  17. Developing and Characterizing Bulk Metallic Glasses for Extreme Applications

    Science.gov (United States)

    Roberts, Scott Nolan

    characterized. Ti 6Al-4V to pure vanadium was chosen for its combination of high strength and light weight on one end, and high melting point on the other. It was inspected by cross-sectional x-ray diffraction, and only the anticipated phases were present. 304L stainless steel to Invar 36 was created in both pillar and as a radial gradient. It combines strength and weldability along with a zero coefficient of thermal expansion material. Only the austenite phase is found to be present via x-ray diffraction. Coefficient of thermal expansion is measured for four compositions, and it is found to be tunable depending on composition.