WorldWideScience

Sample records for alloy steel

  1. Alloyed steel

    International Nuclear Information System (INIS)

    The composition and properties are listed of alloyed steel for use in the manufacture of steam generators, collectors, spacers, emergency tanks, and other components of nuclear power plants. The steel consists of 0.08 to 0.11% w.w. C, 0.6 to 1.4% w.w. Mn, 0.35 to 0.6% w.w. Mo, 0.02 to 0.07% w.w. Al, 0.17 to 0.37% w.w. Si, 1.7 to 2.7% w.w. Ni, 0.03 to 0.07% w.w. V, 0.005 to 0.012% w.w. N, and the rest is Fe. The said steel showed a sufficiently low transition temperature between brittle and tough structures, a greater depth of hardenability, and better weldability than similar steels. (B.S.)

  2. Plating on stainless steel alloys

    International Nuclear Information System (INIS)

    Quantitative adhesion data are presented for a variety of electroplated stainless steel type alloys. Results show that excellent adhesion can be obtained by using a Wood's nickel strike or a sulfamate nickel strike prior to final plating. Specimens plated after Wood's nickel striking failed in the deposit rather than at the interface between the substrate and the coating. Flyer plate quantitative tests showed that use of anodic treatment in sulfuric acid prior to Wood's nickel striking even further improved adhesion. In contrast activation of stainless steels by immersion or cathodic treatment in hydrochloric acid resulted in very reduced bond strengths with failure always occurring at the interface between the coating and substrate

  3. Cleanliness of Alloying Structural Steel

    Institute of Scientific and Technical Information of China (English)

    YU Hui-xiang; WANG Xin-hua; ZHANG Jing; LI Hai-bo; WANG Wan-jun

    2011-01-01

    Alloying structural steel used for mechanical structures has a high requirement for cleanliness because its failures are greatly affected by non-metallic inclusions and total oxygen content in steel.It has been reported by some steelmaking plants to have some problems in controlling total oxygen content and inclusions during alloying structural steel production.For this purpose,cleanliness control in 0.2C-0.3Si-0.6Mn-1Cr-0.2Mo steel was investigated.Firstly,low melting temperature zone(≤1873 K) of CaO-Al2O3-MgO system and formation condition of low melting temperature inclusions were investigated through thermodynamic equilibrium calculation.On this basis,industrial tests were carried out.Through sampling at different stages,transformation of oxide inclusions and change of total oxygen content in steel were studied.The results show that:in order to form CaO-Al2O3-MgO system inclusions with low melting temperature,mass percent of Al2O3,MgO and CaO in inclusions should be controlled from 37.6% to 70.8%,0 to 17.4% and 25.5% to 60.6%;For the condition of 1873 K and 0.05%(mass percent) dissolved aluminum in steel,the activities of dissolved oxygen,magnesium and calcium should be controlled as 0.298×10-4-2×10-4,0.1×10-5-40×10-5 and 0.8×10-8-180×10-8 respectively.With secondary refining proceeding,average total oxygen content and inclusion amount decrease,the type of most inclusions changes from Al2O3 after tapping to Al2O3-MgO after top slag is formed during ladle furnace refining and finally to CaO-Al2O3-MgO after RH treatment.In the final products,average total oxygen content was 12.7×10-6 and most inclusions were in spherical shape with size less than 5 μm.

  4. New structural high strength rationally alloyed steels

    International Nuclear Information System (INIS)

    New developments in high strength structural steels are reported. Properties and perspective fields of application are described for the following materials: austenitic chromium steels with ultra equilibrium nitrogen content, steels with nitrogen martensite structure, microalloyed ferritic-pearlitic steels with decreased concentrations of Mn and Ni, high ductility heat resisting steels, nonmagnetic chromium free Mn-Ni-Cu-V-C steels and iron powder alloys with superhard carbon phases. Steel 02Kh12G14N4YuM is recommended to be used for parts and assemblies of nuclear power plants

  5. 46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Carbon-steel or alloy-steel castings. 59.20-1 Section 59... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The...

  6. High-strength, low-alloy steels.

    Science.gov (United States)

    Rashid, M S

    1980-05-23

    High-strength, low-alloy (HSLA) steels have nearly the same composition as plain carbon steels. However, they are up to twice as strong and their greater load-bearing capacity allows engineering use in lighter sections. Their high strength is derived from a combination of grain refinement; precipitation strengthening due to minor additions of vanadium, niobium, or titanium; and modifications of manufacturing processes, such as controlled rolling and controlled cooling of otherwise essentially plain carbon steel. HSLA steels are less formable than lower strength steels, but dualphase steels, which evolved from HSLA steels, have ferrite-martensite microstructures and better formability than HSLA steels of similar strength. This improved formability has substantially increased the utilization potential of high-strength steels in the manufacture of complex components. This article reviews the development of HSLA and dual-phase steels and discusses the effects of variations in microstructure and chemistry on their mechanical properties. PMID:17772810

  7. Experience with ferrosilicoaluminum alloy during deoxidation of steel

    Directory of Open Access Journals (Sweden)

    A. Mekhtiyev

    2015-10-01

    Full Text Available The article describes the process of deoxidation quiet and low-alloyed steel alloy ferrosilicoaluminum complex in comparison the existing, and with steel deoxidation technology with conventional alloys - ferrosilicon and secondary aluminum. A comparative analysis of quality steel, non-metallic inclusions metallographic studies and studies of the mechanical properties of the resulting steel was done. On a large array of experimental steel proved cost-effectiveness and feasibility of ferrosilicoaluminum during deoxidation quiet and low-alloyed steel.

  8. Nitrogen-alloyed martensitic steels

    International Nuclear Information System (INIS)

    A report is presented on initial results with pressure-nitrided martensitic steels. In heat-resistant steels, thermal stability and toughness are raised by nitrogen. In cold work steel, there is a more favourable corrosion behaviour. (orig./MM)

  9. Compensative alloying of Cr-Si low-alloyed steels

    International Nuclear Information System (INIS)

    The principle of choosing alloy elements in order to suppress the embrittlement of solid solution strengthening is proposed. In the case of Cr-Si low-alloyed steels, the effects of compensative alloying are studied. The ultimate tensile strength and impact toughness of Cr-Si steels microalloyed with Mo, V, and Ti are determined to prove the aspects. The structure of these steels is studied using optical and transmission electron microscopy techniques after applying the optimum heat treatment. The kinetics of phase transformation after quenching and tempering have been examined by means of measurements of specific electrical resistance and magnetic parameters. It is shown that at the Si-content of about 1 wt% high values of tensile strength and impact toughness are simultaneously obtained. It is established by calculations that, for the indicated steel, long-range distortions of the crystal lattice become close to zero at the Si-content of about 1 wt%.

  10. A modification of 4330 alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Gogolewski, R.; Cunningham, B.J. (Lawrence Livermore National Lab., CA (USA)); Gentile, R.; Fleming, S. (Norton Defense Systems, Mahwah, NJ (USA))

    1990-08-01

    We have developed a modification of 4330 alloy steel which does not have an exact equivalent expressed in any standard specification. When we compare the ballistic performance of our modified cast steel in thicknesses of about 120 mm with that of stacked, 24 mm thick rolled 4340 alloy steel plates of comparable hardness and the same total thickness, we do not find a significant difference in terminal ballistic performance against either heavy metal kinetic energy penetrators or precision shaped charges. This result is surprising in relation to contemporary experience in which cast steel has been found to be ballistically inferior to rolled steel against either kinetic energy projectiles or shaped charge warheads. 1 ref., 9 figs.

  11. Low-alloy constructional cast steel

    Directory of Open Access Journals (Sweden)

    D. Bartocha

    2011-07-01

    Full Text Available Production of constructional casting competitive for welded structure of high-strength steel first of all required high metallurgical quality of cast steel. Assumptions, methodology and results of investigation which the aim was determination of the most advantageous: configuration and parameters of metallurgical treatments and ways to modify, in aspects of reach the low-alloy cast steel of the highest quality as possible, are presented. A series of low-alloy cast steel melts modeled on cast steel L20HGSNM was performed, the way of argoning in laboratory induction furnace with a capacity of 50kg was worked out, modifications with additions of FeNb, FeV and master alloy MgCe were performed. During each melts samples of cast steel direct from metal bath were get and series of experimental casting was made. Chemical compositions of melted cast steel, contents of O, N and H were determined as well as influence of additions on structure and nature of impact strength samples fracture were estimated.

  12. Machining of high alloy steels and heat resistant alloys

    International Nuclear Information System (INIS)

    The peculiarities of machining high alloy steels and heat resistant alloys on the base of nickel by cutting are described. The factors worsening the machining of heat resistant materials, namely, the low heat conductivity, strong reverting and high wearing capability, are pointed out. The resign and materials of cutting instruments, providing for high quality machining of heat resistant steels and alloys, are considered. The necessity of regulating thermal processes during cutting with cutting fluids and other coolants (e.g. air with a negative temperature) is noted. The recommended modes of cutting are presented. The efficiency of the conveyer-type method for sawing products and forged intermediate articles is demonstrated by the example of 5KhNM steel

  13. Experience with ferrosilicoaluminum alloy during deoxidation of steel

    OpenAIRE

    Mekhtiyev, A.; Akhmetov, A.; V. Yudakova; Bulatbayev, F.

    2016-01-01

    The article describes the process of deoxidation quiet and low-alloyed steel alloy ferrosilicoaluminum complex in comparison the existing, and with steel deoxidation technology with conventional alloys - ferrosilicon and secondary aluminum. A comparative analysis of quality steel, non-metallic inclusions metallographic studies and studies of the mechanical properties of the resulting steel was done. On a large array of experimental steel proved cost-effectiveness and feasibility of ferrosilic...

  14. Phase transformations in high alloy cold work tool steel

    OpenAIRE

    Šturm, Roman; Moravčík, Roman; Štefániková, Mária; Čička, Roman; Čaplovič, L'ubomír; Kocúrová, Karin

    2015-01-01

    Phase transformations in the alloy tool steels have a crucial effect on the final properties of the steels. High alloy systems have different solidification conditions compared to construction steels. This paper deals with the phase evolution in high alloy tool steel in quasi-equilibrium state. For analysis various methods such as differential thermal analysis, thermomagnetometry, light microscopy, scanning electron microscopy with energy dispersive analysis, X-ray diffraction analysis and di...

  15. Phase transformations in high alloy cold work tool steel:

    OpenAIRE

    Čaplovič, L'.; Čička, Roman; Kocúrová, Karin; Moravčík, Roman; Štefániková, Mária; Šturm, Roman

    2012-01-01

    Phase transformations in the alloy tool steels have a crucial effect on the final properties of the steels. High alloy systems have different solidification conditions compared to construction steels. This paper deals with the phase evolution in high alloy tool steel in quasi-equilibrium state. For analysis various methods such as differential thermal analysis, thermomagnetometry, light microscopy, scanning electron microscopy with energy dispersive analysis, X-ray diffraction analysis and di...

  16. Corrosion of alloy steels in oil field fluids

    International Nuclear Information System (INIS)

    Laboratory and field tests have been conducted on two low alloy and two higher alloy steels at a range of brine salinities and sulfide contents typical of oil well production fluids. AISI types 4130 and 4340 show the same behavior in these fluids as mild steel. AISI type 410 stainless steel and 9% chromium - 1% molybdenum steel corrode at rates as great as that of mild steel at higher chloride or sulfide concentrations. Special corrosion inhibitors are required for higher alloy steels when they are exposed to these conditions

  17. Progress in the development of niobium alloyed high speed steel

    International Nuclear Information System (INIS)

    The development of economy-grades of niobium alloyed high speed steel is described. Both the metallurgical concepts behind the steel design and the results of performance tests are presented. (Author)

  18. Crack stability analysis of low alloy steel primary coolant pipe

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.; Kameyama, M. [Kansai Electric Power Company, Osaka (Japan); Urabe, Y. [Mitsubishi Heavy Industries, Ltd., Takasago (Japan)] [and others

    1997-04-01

    At present, cast duplex stainless steel has been used for the primary coolant piping of PWRs in Japan and joints of dissimilar material have been applied for welding to reactor vessels and steam generators. For the primary coolant piping of the next APWR plants, application of low alloy steel that results in designing main loops with the same material is being studied. It means that there is no need to weld low alloy steel with stainless steel and that makes it possible to reduce the welding length. Attenuation of Ultra Sonic Wave Intensity is lower for low alloy steel than for stainless steel and they have advantageous inspection characteristics. In addition to that, the thermal expansion rate is smaller for low alloy steel than for stainless steel. In consideration of the above features of low alloy steel, the overall reliability of primary coolant piping is expected to be improved. Therefore, for the evaluation of crack stability of low alloy steel piping to be applied for primary loops, elastic-plastic future mechanics analysis was performed by means of a three-dimensioned FEM. The evaluation results for the low alloy steel pipings show that cracks will not grow into unstable fractures under maximum design load conditions, even when such a circumferential crack is assumed to be 6 times the size of the wall thickness.

  19. New Stainless Steel Alloys for Low Temperature Surface Hardening?

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Somers, Marcel A. J.

    2015-01-01

    The present contribution showcases the possibility for developing new surface hardenable stainless steels containing strong nitride/carbide forming elements (SNCFE). Nitriding of the commercial alloys, austenitic A286, and ferritic AISI 409 illustrates the beneficial effect of having SNCFE present...... in the stainless steel alloys. The presented computational approach for alloy design enables “screening” of hundreds of thousands hypothetical alloy systems by use of Thermo-Calc. Promising compositions for new stainless steel alloys can be selected based on imposed criteria, i.e. facilitating easy...

  20. Niobium in steels and alloys

    International Nuclear Information System (INIS)

    Data are presented on the reserves and processing of niobium raw materials followed by brief review of the current status and long-range trends in the commercial usage of niobium and its compounds. A survey is made of the physical properties of niobium and its chemical reactions with elements of direct concern in the manufacture of ferroalloys, quality steels and other products. Niobium minerals and ores, along with common ore processing practices are described briefly. Attention is paid to Brazilian niobium ores, and to the Araxa deposit specifically. Some emphasis has been given to methods of processing lean niobium ores not easily amenable to simple concentration. A systematic review is presented of the techniques used in the production of niobium ferroalloys. (E.G.)

  1. Amorphous Alloy Surpasses Steel and Titanium

    Science.gov (United States)

    2004-01-01

    In the same way that the inventions of steel in the 1800s and plastic in the 1900s sparked revolutions for industry, a new class of amorphous alloys is poised to redefine materials science as we know it in the 21st century. Welcome to the 3rd Revolution, otherwise known as the era of Liquidmetal(R) alloys, where metals behave similar to plastics but possess more than twice the strength of high performance titanium. Liquidmetal alloys were conceived in 1992, as a result of a project funded by the California Institute of Technology (CalTech), NASA, and the U.S. Department of Energy, to study the fundamentals of metallic alloys in an undercooled liquid state, for the development of new aerospace materials. Furthermore, NASA's Marshall Space Flight Center contributed to the development of the alloys by subjecting the materials to testing in its Electrostatic Levitator, a special instrument that is capable of suspending an object in midair so that researchers can heat and cool it in a containerless environment free from contaminants that could otherwise spoil the experiment.

  2. Fracture toughness of irradiated stainless steel alloys

    International Nuclear Information System (INIS)

    The postirradiation fracture toughness responses of Types 316 and 304 stainless steel (SS) wrought products, cast CF8 SS and Type 308 SS weld deposit were characterized at 4270C using J/sub R/-curve techniques. Fast-neutron irradiation of these alloys caused an order of magnitude reduction in J/sub c/ and two orders of magnitude reduction in tearing modulus at neutron exposures above 10 dpa, where radiation-induced losses in toughness appeared to saturate. Saturation J/sub c/ values for the wrought materials ranged from 28 to 31 kJ/m2; the weld exhibited a saturation level of 11 kJ/m2. Maximum allowable flaw sizes for highly irradiated stainless steel components stressed to 90% of the unirradiated yield strength are on the order of 3 cm for the wrought material and 1 cm for the weld. Electron fractographic examination revealed that irradiation displacement damage brought about a transition from ductile microvoid coalescence to channel fracture, associated with local separation along planar deformation bands. The lower saturation toughness value for the weld relative to that for the wrought products was attributed to local failure of ferrite particles ahead of the advancing crack which prematurely initiated channel fracture

  3. Implantation-plasma treatment of martensitic steel and titanium alloy

    International Nuclear Information System (INIS)

    One of the effective methods of deep modification of the surface of steels and alloys is the combination of ion implantation and plasma nitriding. In this work, the long-range effect is demonstrated in the case of combination of the effect of high- and low-energy ions of nitrogen on a martensitic steel for each ion implantation is usually not effective, and a titanium alloy used widely in industry

  4. Semidirect alloying of steel with vanadium-containing exothermic briquettes

    International Nuclear Information System (INIS)

    Exothermic vanadium-containing briquettes are designed and tested in practice. Briquettes allow introducing up to 0.15% V into the steel, vanadium recovery from converter slag being reached 94%. Ladle steel alloying by the briquettes decreases cost by 2-4% and aluminium consumption by a factor of 1.5. The briquettes consist of converter slag (15,54-19,65%V2O5), master alloy (6.18-6.95%V), aluminium and dolomite. 1 ref

  5. 48 CFR 252.225-7030 - Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate.

    Science.gov (United States)

    2010-10-01

    ... of Carbon, Alloy, and Armor Steel Plate. 252.225-7030 Section 252.225-7030 Federal Acquisition... Acquisition of Carbon, Alloy, and Armor Steel Plate. As prescribed in 225.7011-3, use the following clause: Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate (DEC 2006) (a) Carbon, alloy, and...

  6. Cracking in electron beam welding of low alloy steels

    International Nuclear Information System (INIS)

    The study of the cracking in electron beam welding of low alloy steel plates (steel ASTM-A387 gr 22) of high thickness shows that the welding speed to be the essential parameter. A low speed improves the resistance to cracking. The low segregation obtained with this process minimizes the effect of impurities

  7. Properties of Mo-alloyed sintered manganese steels

    International Nuclear Information System (INIS)

    Sintered alloy steels are needed for mostly PM structural parts. Powder metallurgy techniques provide a means of fabricating high quality steel parts with tailored mechanical properties. It is now possible to produce sintered steel parts with properties equal to an even superior to those of parts made by more traditional routes. Challenges arise both with the material selection and component fabrication. This work outlines the processing for high performance structural application. (author)

  8. Steel alloys having enhanced thermal neutron absorption properties

    International Nuclear Information System (INIS)

    Alloy steels having enhanced neutron absorption properties are formed by mixing a neutron absorption element (eg boron) in powder form with steel powder in a proportion sufficient to promote in the compacted, sintered, product a thermal neutron absorption fraction, expressed as a percentage of greater than 20% per mm of thickness. As an alternative to blending, the absorption element may be prealloyed into a steel melt prior to atomisation. (author)

  9. Comparison of Impact Properties for Carbon and Low Alloy Steels

    Institute of Scientific and Technical Information of China (English)

    O.H. Ibrahim

    2011-01-01

    The impact properties of hot rolled carbon steel (used for the manufacture of reinforcement steel bars) and the quenched & tempered (Q&T) low alloy steel (used in the pressure vessel industry) were determined. The microstructure of the hot rolled carbon steel contained ferrite/pearlite phases, while that of the quenched and tempered low alloy steel contained bainite structure. Impact properties were determined for both steels by instrumented impact testing at temperatures between -150 and 200℃. The impact properties comprised total impact energy, ductile to brittle transition temperature, crack initiation and propagation energy, brittleness transition temperature and cleavage fracture stress. The Q&T low alloy steel displayed much higher resistance to ductile fracture at high test temperatures, while its resistance to brittle fracture at low test temperatures was a little higher than that of the hot rolled carbon steel. The results were discussed in relation to the difference in the chemical composition and microstructure for the two steels.

  10. MODULATED STRUCTURES AND ORDERING STRUCTURES IN ALLOYING AUSTENITIC MANGANESE STEEL

    Institute of Scientific and Technical Information of China (English)

    L. He; Z.H. Jin; J.D. Lu

    2001-01-01

    The microstructure of Fe-10Mn-2Cr-1.5C alloy has been investigated with transmission electron microscopy and X-ray diffractometer. The superlattice diffraction spots and satellite reflection pattrens have been observed in the present alloy, which means the appearence of the ordering structure and modulated structure in the alloy. It is also proved by X-ray diffraction analysis that the austenite in the alloy is more stable than that in traditional austenitic manganese steel. On the basis of this investigation,it is suggested that the C-Mn ordering clusters exist in austenitic manganese steel and the chromium can strengthen this effect by linking the weaker C-Mn couples together,which may play an important role in work hardening of austenitic manganese steel.

  11. Milling and Drilling Evaluation of Stainless Steel Powder Metallurgy Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lazarus, L.J.

    2001-12-10

    Near-net-shape components can be made with powder metallurgy (PM) processes. Only secondary operations such as milling and drilling are required to complete these components. In the past and currently production components are made from powder metallurgy (PM) stainless steel alloys. process engineers are unfamiliar with the difference in machining properties of wrought versus PM alloys and have had to make parts to develop the machining parameters. Design engineers are not generally aware that some PM alloy variations can be furnished with machining additives that greatly increase tool life. Specimens from a MANTEC PM alloy property study were made available. This study was undertaken to determine the machining properties of a number of stainless steel wrought and PM alloys under the same conditions so that comparisons of their machining properties could be made and relative tool life determined.

  12. Performance of stainless steel treated by plasma niobium alloying

    International Nuclear Information System (INIS)

    Nb alloyed layer was prepared by plasma surface alloying technology on surface of stainless steel substrates. Microstructure morphology, depth profiling of the elemental composition and phase structure of the alloyed layer were analyzed. Corrosion performance of the Nb alloyed layer was investigated. The results show that the optimum parameters were: temperature, 1100 degree C; air pressure, 80 Pa, holding time 3 h, source voltage, 900-700 V; and cathode voltage, 600-450 V. The thickness of Nb alloyed layer was about 60 μm. The alloyed layer was mainly composed of NbC and Nb6C5, Cr2Nb and Fe2Nb. The surface Nb content was 50%, which decreased sharply in the first several microns of depths and then gradually in further depths. The Nb alloyed layer has improved resistance to intergranular corrosion and uniform corrosion. (authors)

  13. REVIEW AND PROSPECT OF HIGH STRENGTH LOW ALLOY TRIP STEEL

    Institute of Scientific and Technical Information of China (English)

    L. Li; P. Wollants; Y.L. He; B.C. De Cooman; X.C. Wei; Z.Y. Xu

    2003-01-01

    Research status of high strength low alloy TRIP (transformation induced plasticity)steels for automobile structural parts is briefly described. Composition and microstructure factors especially the morphology, size and volume fraction of retained austenite,which largely influence the strength and ductility of the steel, are reviewed and discussed one after another. Modelling of the inter-critical annealing and martempering processes as well as the designing of the TRIP steel aided by commercial software are introduced. Some special aspects of the dynamic mechanical properties of TRIP steel are firstly reported.

  14. High-strength shape memory steels alloyed with nitrogen

    International Nuclear Information System (INIS)

    Since shape memory effect in Fe-Mn-Si systems was observed, increasing attention has been paid to iron based shape memory alloys due to their great technological potential. Properties of Fe-Mn-Si shape memory alloys have been improved by alloying with Cr, Ni, Co and C. A significant improvement on shape memory, mechanical and corrosion properties is attained by introducing nitrogen in Fe-Mn-Si based systems. By increasing the nitrogen content, strength of the matrix increases and the stacking fault energy decreases, which promote the formation of stress induced martensite and decrease permanent slip. The present authors have shown that nitrogen alloyed shape memory steels exhibit recoverable strains of 2.5--4.2% and recovery stresses of 330 MPa. In some cases, stresses over 700 MPa were attained at room temperature after cooling a constrained sample. Yield strengths of these steels can be as high as 1,100 MPa and tensile strengths over 1,500 MPa with elongations of 30%. In the present study, effect of nitrogen alloying on shape memory and mechanical properties of Fe-Mn-Si, Fe-Mn-Si-Cr-Ni and Fe-Mn-Cr-Ni-V alloys is studied. Nitrogen alloying is shown to exhibit a beneficial effect on shape memory properties and strength of these steels

  15. Boric acid corrosion of low alloy steel

    International Nuclear Information System (INIS)

    In the last decade, the industry has been aware of a potential loss of coolant accident (LOCA) per the following scenario: primary water stress corrosion cracking (PWSCC) of a primary system component or weld leads to a coolant leak, the coolant corrodes a low alloy steel structural component (e.g., the reactor vessel (RV) or the reactor vessel head (RVH)), and corrosion degrades the pressure boundary leading to a loss of coolant accident. The industry has taken several steps to address this concern, including replacement of the most susceptible components (RVH replacement), enhanced inspection (both NDE of components and visual inspections for boric acid deposits), and safety analyses to determine appropriate inspection intervals. Although these measures are generally thought to have adequately addressed this issue, there have been some uncertainties in the safety analyses which the industry has sought to address in order to quantify the extent of conservatism in the safety analyses. Specifically, there has been some uncertainty regarding the rate of boric acid corrosion under various conditions which might arise due to a PWSCC leak and the extent to which boric acid deposits are retained near the leak under various geometries. This paper reviews the results of the Electric Power Research Institute (EPRI) Materials Reliability Program (MRP) boric acid corrosion (BAC) test programs conducted over the last 8 years, focusing on the most recent results of full-scale mockup testing of CRDM nozzle and bottom mounted nozzle (BMN) configurations. The main purpose of this presentation is to provide an overview of the latest understanding of the risk of boric acid corrosion as it is informed by the results of the testing conducted over the last eight years. The rate of boric acid corrosion has been found to be a function of many factors, including initial chemistry, the extent of concentration due to boiling, the temperature at which concentration takes place, the velocity

  16. Effect of alloy elements on the anti-corrosion properties of low alloy steel

    Indian Academy of Sciences (India)

    Baorong Hou; Yantao Li; Yanxu Li; Jinglei Zhang

    2000-06-01

    Effect of alloy elements on corrosion of low alloy steel was studied under simulated offshore conditions. The results showed that the elements Cu, P, Mo, W, V had evident effect on corrosion resistance in the atmosphere zone; Cu, P, V, Mo in the splash zone and Cr, Al, Mo in the submerged zone.

  17. Heat treatment of heavy section low alloy steel plates

    International Nuclear Information System (INIS)

    Heavy section low alloy steel plates are used for nuclear reactor and direct oil desulfurizing reactor pressure vessels, etc. High integrity is, therefore, required of these steel plates. The factors which affect the internal soundness and notch toughness of heavy section low alloy steel plates are discussed in relation to heat treatment after rolling. Precipitation behavior of aluminum nitride in A533B steel plates during heat treatment after rolling is described with respect to the austenite grain size and notch toughness of the plate after final rolling. Cooling down to 4000C before normalizing is recommended to obtain good notch toughness. Selection of temperature and time for dehydrogenation at the ferrite region is discussed and it is shown that the optimum temperature for dehydrogenation must be determined by taking microsegregation in the plate into consideration. (author)

  18. Cold cracks in the welding of alloy-treated steels

    International Nuclear Information System (INIS)

    Cold shortness is one of the most frequent causes of failure when alloy-treated steels are welded. It occurs in different forms, but distinguishes itself by the fact that its appearance is directly associated with the welding process and exhibits predominantly an intercrystalline form which shows a typical formation especially under a raster electron microscope. The purpose of this paper is to describe experience of the subject of cold shortness of alloy-treated steels, to explain the appearances of these cold cracks in their various forms, to elucidate the causes of the occurrence of such cracks and to postulate possible remedial measures. (orig.)

  19. Cold cracks in the welding of alloy-treated steels

    Energy Technology Data Exchange (ETDEWEB)

    Cerjak, H.; Breckwoldt, E.; Loehberg, R.; Schmidt, J.; Papouschek, F.

    1982-04-01

    Cold shortness is one of the most frequent causes of failure when alloy-treated steels are welded. It occurs in different forms, but distinguishes itself by the fact that its appearance is directly associated with the welding process and exhibits predominantly an intercrystalline form which shows a typical formation especially under a raster electron microscope. The purpose of this paper is to describe experience of the subject of cold shortness of alloy-treated steels, to explain the appearances of these cold cracks in their various forms, to elucidate the causes of the occurrence of such cracks and to postulate possible remedial measures.

  20. Laves intermetallics in stainless steel-zirconium alloys

    International Nuclear Information System (INIS)

    Laves intermetallics have a significant effect on properties of metal waste forms being developed at Argonne National Laboratory. These waste forms are stainless steel-zirconium alloys that will contain radioactive metal isotopes isolated from spent nuclear fuel by electrometallurgical treatment. The baseline waste form composition for stainless steel-clad fuels is stainless steel-15 wt.% zirconium (SS-15Zr). This article presents results of neutron diffraction measurements, heat-treatment studies and mechanical testing on SS-15Zr alloys. The Laves intermetallics in these alloys, labeled Zr(Fe,Cr,Ni)2+x, have both C36 and C15 crystal structures. A fraction of these intermetallics transform into (Fe,Cr,Ni)23Zr6 during high-temperature annealing; the authors have proposed a mechanism for this transformation. The SS-15Zr alloys show virtually no elongation in uniaxial tension, but exhibit good strength and ductility in compression tests. This article also presents neutron diffraction and microstructural data for a stainless steel-42 wt.% zirconium (SS-42Zr) alloy

  1. Mechanical properties of low alloy high phosphorus weathering steel

    OpenAIRE

    Jena B.K.; Gupta N; Singh B; Ahoo G.S.

    2015-01-01

    Mechanical behaviour of two low alloy steels (G11 and G12) was studied with respect to different phosphorus contents. Tensile strength and yield strength increased while percentage elongation at fracture decreased on increasing phosphorus content. The SEM and light optical photomicrograph of low phosphorus steel (G11) revealed ferrite and pearlite microstructure. On increasing phosphorus content from 0.25 wt.% to 0.42 wt.%, the morphology of grain changed f...

  2. Feasibility of underwater friction stir welding of hardenable alloy steel

    OpenAIRE

    Overfield, Norman E.

    2010-01-01

    Approved for public release; distribution is unlimited The objective of this thesis is to determine whether friction stir welding (FSW) is a feasible welding process for steels in an underwater environment. Specific benefits would be underwater weld repairs on steel alloy piping systems and/or structures, and crack repairs on control surfaces of submarines without the need for strict environment controls or in the submarine's case, for drydocking. A single tool made of polycrystaline cub...

  3. 76 FR 78882 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Affirmative Preliminary Determination of...

    Science.gov (United States)

    2011-12-20

    ... Steel Plate From Canada, 66 FR 7617, 7618 (January 24, 2001)) (Canadian Plate), and accompanying Issued... this order is certain hot-rolled products of carbon steel and alloy steel, in coils, of approximately... International Trade Administration Carbon and Certain Alloy Steel Wire Rod From Mexico: Affirmative...

  4. Kinetics of chemical interactions between zirconium alloys and stainless steels

    International Nuclear Information System (INIS)

    The chemical interaction kinetics of reactor core component zirconium alloys and stainless steels at high temperatures was examined. Interaction of as-received and preoxidized Zr1%Nb with X18H10T stainless steel used in WWER type nuclear reactors, and also that of Zircaloy-4 and AISI-316 stainless steel, for comparison, were investigated. The reaction rate measurements were supplemented with post-test metallographical examinations. Results are presented and evaluated, and compared with literature data. (author). 14 refs., 31 figs., 8 tabs

  5. Development of briquettes for steel semidirect alloying with vanadium

    International Nuclear Information System (INIS)

    Based on ferrovanadium type FS40Vd and vanadium-containing containing converter slag the briquettes for alloying steels type 20-60 KhN with vanadium were developed and commercially used. Component content ratios and desired granulometric composition which allow to recover 89-94 % V from a converter slag are determined. The master alloy with silicon concentration ranged within 45-50 % is considered to be optimum, bearing in mind the melting temperature, the density of initial and final alloys, aluminium consumption and vanadium yield from briquettes. 7 refs.; 3 figs.; 4 tabs

  6. Thermal treatment of PM-tool steel alloyed with niobium

    Energy Technology Data Exchange (ETDEWEB)

    Pavlickova, M.; Vojtech, D.; Novak, P.; Gemperlova, J.; Gemperle, A.; Zarubova, N.; Lejcek, P.; Jurci, P.; Stolar, P

    2003-09-15

    The work is aimed at describing the influence of thermal treatment on the properties of a tool steel containing (in wt.%) 2.5% C, 3.3% Si, 6.2% Cr, 2.2% Mo, 2.6% V, 2.6% Nb, 1.0% W prepared by the powder metallurgy process. Alloying with niobium positively affects the microstructure, the mechanical properties and the performance of the steel. The microstructure of the hardened steel is composed of a martensitic matrix, retained austenite and various types of carbide. During tempering of the hardened steel at the temperatures above 480 deg. C precipitation of very fine carbides occurs, which results in secondary hardening. The optimum thermal treatment of the steel is austenitisation at 1050-1100 deg. C, nitrogen cooling and tempering at 540 deg. C (3x1 h)

  7. Thermal treatment of PM-tool steel alloyed with niobium

    International Nuclear Information System (INIS)

    The work is aimed at describing the influence of thermal treatment on the properties of a tool steel containing (in wt.%) 2.5% C, 3.3% Si, 6.2% Cr, 2.2% Mo, 2.6% V, 2.6% Nb, 1.0% W prepared by the powder metallurgy process. Alloying with niobium positively affects the microstructure, the mechanical properties and the performance of the steel. The microstructure of the hardened steel is composed of a martensitic matrix, retained austenite and various types of carbide. During tempering of the hardened steel at the temperatures above 480 deg. C precipitation of very fine carbides occurs, which results in secondary hardening. The optimum thermal treatment of the steel is austenitisation at 1050-1100 deg. C, nitrogen cooling and tempering at 540 deg. C (3x1 h)

  8. Method for plastic working of low-alloy steel

    International Nuclear Information System (INIS)

    To obtain fine-grained structure and to increase plasticity, the method of treating low-alloyed steel (0.1-0.3% C) is suggested. The method includes heating up to temperatures Ac1-Ac1+30 deg C, deformation with the degree of 50-70% and the rate 10-3-10-1 c-1, short-time hold-up up to 30 s at this temperature. The 15KhSND steel is taken for example. The use of this method will permit to obtain fine-grained structure in steels with the grain size up to 5 μm, in this case the plasticity of steel is 3-4 times higher than after treatment according to the known method, and the steel flow stress is 1.5-2 times lower

  9. On the rational alloying of structural chromium-nickel steels

    International Nuclear Information System (INIS)

    A study was made on the influence of chromium nickel, phosphorus on the critical brittleness temperature of Cr-Ni-Mo-V structural steels. It is shown that the critical brittleness temperature of these steels increases at chromium content more over than 2% and nickel content more than 2% in the result of carbide transformations during tempering. Increase of nickel content in Cr-Ni-Mo-V-steels strengthens the tendency to embrittlement during slow cooling, from tempering temperature owing to development of process of phosphorus grain-boundary segregation. Two mentioned mechanisms of embrittlement determine principles of rational steel alloying. The extreme dependence of the critical brittleness temperature on chromium and nickel content, which enables to choose the optimum composition of Cr-Ni-Mo-V-steels, was established

  10. High specialty stainless steels and nickel alloys for FGD dampers

    Energy Technology Data Exchange (ETDEWEB)

    Herda, W.R.; Rockel, M.B.; Grossmann, G.K. [Krupp VDM GmbH, Werdohl (Germany); Starke, K. [Mannesmann-Seiffert GmbH, Beckum (Germany)

    1997-08-01

    Because of process design and construction, FGD installations normally have bypass ducts, which necessitates use of dampers. Due to corrosion from acid dew resulting from interaction of hot acidic flue gases and colder outside environments, carbon steel cannot be used as construction material under these specific conditions. In the past, commercial stainless steels have suffered by pitting and crevice corrosion and occasionally failed by stress corrosion cracking. Only high alloy specialty super-austenitic stainless steels with 6.5% Mo should be used and considered for this application. Experience in Germany and Europe has shown that with regard to safety and life cycle cost analysis as well as providing a long time warranty, a new specialty stainless steel, alloy 31--UNS N08031--(31 Ni, 27 Cr, 6.5 Mo, 0.2 N) has proven to be the best and most economical choice. Hundreds of tons in forms of sheet, rod and bar, as well as strip (for damper seals) have been used and installed in many FGD installations throughout Europe. Under extremely corrosive conditions, the new advanced Ni-Cr-Mo alloy 59--UNS N06059--(59 Ni, 23 Cr, 16 Mo) should be used. This paper describes qualification and workability of these alloys as pertains to damper applications. Some case histories are also provided.

  11. Opportunities and challenges of spray forming high-alloyed steels

    International Nuclear Information System (INIS)

    Spray forming has proven to be a useful tool for generating high-alloyed materials. The metallurgical advantages of high solidification rates are obvious. Shortening of process chains in comparison to powder metallurgy is often discussed. To approach to some of the remaining questions, especially on the influence of process gases on spray forming steels, within this study high-alloyed steels with melt weights up to 150 kg are spray formed and hot worked to semi-finished materials. Properties are analyzed in comparison to products available on the market. Cold-work tool steels with high carbon content can be spray formed to produce materials with good wear resistance and toughness. When reducing the carbon content and the amount of hard carbides, advantage of reduced segregation becomes more apparent. On the other hand, the influence of nitrogen as an alloying element is more effective and means of control are required. When corrosion or heat resistant steels with high non-carbide bonded chromium content or other nitride forming elements are part of the alloy, care has to be taken on controlling the dissolution of process gases and subsequent precipitation and degassing during compaction and further processing. Experiments where melt protection and atomization gas were changed from nitrogen to argon have shown significant influence of process gases on spray forming results and the mechanical properties of the materials in hot worked and finally heat treated condition

  12. Development of highest strength nitrogen alloyed austenitic steels

    International Nuclear Information System (INIS)

    This work deals with different possibilities to increase the strength of austenitic stainless steels. It may be interesting to the steel producer and to the steel user, because it shows ways to increase the strength of such steels. It may also be of interest to the metallurgist, because it analyzes the achieved results on the basis of physical metallurgy. It is shown that the increase of the nitrogen content in solid solution has a positive effect on the different hardening mechanisms. The investigation, therefore, focus on nitrogen alloyed steels. Grain boundary hardening, the increase of strength with decreasing strain size, is strongly pronounced in nitrogen alloyed steels. By means of an ultra rapid recrystallization heat treatment it is possible to produce a grain size as small as 2-3 microns. The yield strength reaches an unusually high value of 1030 MPa with an elongation of 48% and an area reduction of 63%. This completely recrystallized steel is free of any precipitation. From the Hall-Petch relation the yield strength may only be extrapolated down to a grain size of about 10 microns. The slope of the Hall-Petch plot, ky, decreases with decreasing grain size. This behavior may be explained by the different distribution of dislocation glide in fine and in coarse grained material. Strain hardening, the increase of strength due to deformation, was thoroughly investigated as a second hardening mechanism. The most important results for room temperature deformation are presented. Deformation at an increased temperature of about 300-400 oC was investigated as an alternative to room temperature deformation. The potentially useful results are also presented. Strain aging may further increase the strength of cold worked nitrogen alloys steels. A heat treatment between 300 and 500oC for a few minutes may lead to an increase in strength of more than 300 MPa. (author) 73 figs., refs

  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. Neutron irradiation creep in stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Schuele, Wolfgang (Commission of the European Union, Institute for Advanced Materials, I-21020 Ispra (Vatican City State, Holy See) (Italy)); Hausen, Hermann (Commission of the European Union, Institute for Advanced Materials, I-21020 Ispra (Vatican City State, Holy See) (Italy))

    1994-09-01

    Irradiation creep elongations were measured in the HFR at Petten on AMCR steels, on 316 CE-reference steels, and on US-316 and US-PCA steels varying the irradiation temperature between 300 C and 500 C and the stress between 25 and 300 MPa. At the beginning of an irradiation a type of primary'' creep stage is observed for doses up to 3-5 dpa after which dose the secondary'' creep stage begins. The primary'' creep strain decreases in cold-worked steel materials with decreasing stress and decreasing irradiation temperature achieving also negative creep strains depending also on the pre-treatment of the materials. These primary'' creep strains are mainly attributed to volume changes due to the formation of radiation-induced phases, e.g. to the formation of [alpha]-ferrite below about 400 C and of carbides below about 700 C, and not to irradiation creep. The secondary'' creep stage is found for doses larger than 3 to 5 dpa and is attributed mainly to irradiation creep. The irradiation creep rate is almost independent of the irradiation temperature (Q[sub irr]=0.132 eV) and linearly dependent on the stress. The total creep elongations normalized to about 8 dpa are equal for almost every type of steel irradiated in the HFR at Petten or in ORR or in EBR II. The negative creep elongations are more pronounced in PCA- and in AMCR-steels and for this reason the total creep elongation is slightly smaller at 8 dpa for these two steels than for the other steels. ((orig.))

  15. Neutron irradiation creep in stainless steel alloys

    Science.gov (United States)

    Schüle, Wolfgang; Hausen, Hermann

    1994-09-01

    Irradiation creep elongations were measured in the HFR at Petten on AMCR steels, on 316 CE-reference steels, and on US-316 and US-PCA steels varying the irradiation temperature between 300°C and 500°C and the stress between 25 and 300 MPa. At the beginning of an irradiation a type of "primary" creep stage is observed for doses up to 3-5 dpa after which dose the "secondary" creep stage begins. The "primary" creep strain decreases in cold-worked steel materials with decreasing stress and decreasing irradiation temperature achieving also negative creep strains depending also on the pre-treatment of the materials. These "primary" creep strains are mainly attributed to volume changes due to the formation of radiation-induced phases, e.g. to the formation of α-ferrite below about 400°C and of carbides below about 700°C, and not to irradiation creep. The "secondary" creep stage is found for doses larger than 3 to 5 dpa and is attributed mainly to irradiation creep. The irradiation creep rate is almost independent of the irradiation temperature ( Qirr = 0.132 eV) and linearly dependent on the stress. The total creep elongations normalized to about 8 dpa are equal for almost every type of steel irradiated in the HFR at Petten or in ORR or in EBR II. The negative creep elongations are more pronounced in PCA- and in AMCR-steels and for this reason the total creep elongation is slightly smaller at 8 dpa for these two steels than for the other steels.

  16. Neutron irradiation creep in stainless steel alloys

    International Nuclear Information System (INIS)

    Irradiation creep elongations were measured in the HFR at Petten on AMCR steels, on 316 CE-reference steels, and on US-316 and US-PCA steels varying the irradiation temperature between 300 C and 500 C and the stress between 25 and 300 MPa. At the beginning of an irradiation a type of ''primary'' creep stage is observed for doses up to 3-5 dpa after which dose the ''secondary'' creep stage begins. The ''primary'' creep strain decreases in cold-worked steel materials with decreasing stress and decreasing irradiation temperature achieving also negative creep strains depending also on the pre-treatment of the materials. These ''primary'' creep strains are mainly attributed to volume changes due to the formation of radiation-induced phases, e.g. to the formation of α-ferrite below about 400 C and of carbides below about 700 C, and not to irradiation creep. The ''secondary'' creep stage is found for doses larger than 3 to 5 dpa and is attributed mainly to irradiation creep. The irradiation creep rate is almost independent of the irradiation temperature (Qirr=0.132 eV) and linearly dependent on the stress. The total creep elongations normalized to about 8 dpa are equal for almost every type of steel irradiated in the HFR at Petten or in ORR or in EBR II. The negative creep elongations are more pronounced in PCA- and in AMCR-steels and for this reason the total creep elongation is slightly smaller at 8 dpa for these two steels than for the other steels. ((orig.))

  17. Liquid Phase Sintering of Highly Alloyed Stainless Steel

    DEFF Research Database (Denmark)

    Mathiesen, Troels

    1996-01-01

    calculations, made by use of the computer programme Thermo-Calc, were also correlated with the observed microstructure. Corrosion measurements by electrochemical techniques show no signs of intergranular corrosion in contrast to the case of AISI 316L based steel. Furthermore most of the material showed......Liquid phase sintering of stainless steel is usually applied to improve corrosion resistance by obtaining a material without an open pore system. The dense structure normally also give a higher strength when compared to conventional sintered steel. Liquid phase sintrering based on addition of...... boride to AISI 316L type steels have previously been studied, but were found to be sensitive to intergranular corrosion due to formation of intermetallic phases rich in chromium and molybdenum. In order to improve this system further, new investigations have focused on the use of higher alloyed stainless...

  18. PVD hard coatings on prenitrided low alloy steel

    International Nuclear Information System (INIS)

    The combination of traditional surface treatments such as nitriding with modern plasma-enhanced surface technologies reveals the possibility, particularly in the application to low alloy steels, of obtaining mechanical properties comparable with those of high alloy steels. Gas-nitrided samples of the hardened and tempered low alloy steels 30CrMoV9 and 17CrMoV10 were TiN coated by r.f. magnetron sputtering and ion plating. The requirements to obtain a nitrided substrate that can be coated were given special consideration. For this, various surface modifications of the nitrided substrates were realized by bright nitriding, nitriding with a compound layer and additional steps before coating, such as polishing, grinding and sputter cleaning. The properties of prenitrided coated steels essentially depend on the structure and properties of the outer part of the nitrided case. TiN on bright nitrided and nitrided substrates with the compound layer removed has a better adherence than on compound layers. The decomposition of the iron nitride during the plasma sputter cleaning of compound layers results in a lower surface hardness and lower adherence of TiN. The highest wear resistances in the Timken test were registered on samples where the compound layer had been removed before TiN coating. (orig.)

  19. Virtual examinations of alloying elements influence on alloy structural steels mechanical properties

    OpenAIRE

    L.A. Dobrzański; R. Honysz

    2011-01-01

    Purpose: The paper introduces analysis results of selected alloying elements influence on mechanical properties of alloy structural steels for quenching and tempering.Design/methodology/approach: Investigations were performed in virtual environment with use of materials science virtual laboratory. Virtual investigations results were verified in real investigative laboratory.Findings: Materials researches performed with use of material science virtual laboratory in range of determining the mec...

  20. 76 FR 45509 - Final Results of Antidumping Duty Changed Circumstances Review: Carbon and Certain Alloy Steel...

    Science.gov (United States)

    2011-07-29

    ... Circumstances Review: Carbon and Certain Alloy Steel Wire Rod from Mexico, 75 FR 67685 (November 3, 2010...: Carbon and Certain Alloy Steel Wire Rod From Mexico, 71 FR 27989 (May 15, 2006). Notification This notice... of the Order The merchandise subject to this order is certain hot-rolled products of carbon steel...

  1. Oxidation behavior of steels and Alloy 800 in supercritical water

    International Nuclear Information System (INIS)

    The oxidation behavior of a ferritic-martensitic steel T91 and a martensitic steel AISI 403 up to 750 h, and of AISI 316L and Alloy 800 up to 336 h in deaerated supercritical water, 450ºC-25 MPa, was investigated in this paper. After exposure up to 750 h, the weight gain data, for steels T91 and AISI 403, was fitted by ∆W=k tn, were n are similar for both steels and k is a little higher for T91. The oxide films grown in the steels were characterized using gravimetry, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction. The films were adherent and exhibited a low porosity. For this low oxygen content supercritical water exposure, the oxide scale exhibited a typical duplex structure, in which the scale is composed of an outer iron oxide layer of magnetite (Fe3O4) and an inner iron/chromium oxide layer of a non-stoichiometric iron chromite (Fe,Cr)3O4. Preliminary results, with AISI 316L and Alloy 800, for two exposure periods (168 and 336 h), are also reported. The morphology shown for the oxide films grown on both materials up to 336 h of oxidation in supercritical water, resembles that of a duplex layer film like that shown by stainless steels and Alloy 800 oxide films grown in a in a high temperature and pressure (220-350ºC) of a primary or secondary coolant of a plant. (author)

  2. Mechanical properties of low alloy high phosphorus weathering steel

    Directory of Open Access Journals (Sweden)

    Jena B.K.

    2015-01-01

    Full Text Available Mechanical behaviour of two low alloy steels (G11 and G12 was studied with respect to different phosphorus contents. Tensile strength and yield strength increased while percentage elongation at fracture decreased on increasing phosphorus content. The SEM and light optical photomicrograph of low phosphorus steel (G11 revealed ferrite and pearlite microstructure. On increasing phosphorus content from 0.25 wt.% to 0.42 wt.%, the morphology of grain changed from equiaxed shape to pan-cake shape and grain size also increased. The Charpy V notch (CVN impact energy of G11 and G12 steel at room temperature was 32 J and 4 J respectively and their fractographs revealed brittle rupture with cleavage facets for both the steels. However, the fractograph of G11 steel after tensile test exhibited ductile mode of fracture with conical equiaxed dimple while that of G12 steel containing 0.42 wt. % P exhibited transgranular cleavage fracture. Based on this study, G11 steel containing 0.25 wt. % P could be explored as a candidate material for weathering application purpose where the 20°C toughness requirement is 27 J as per CSN EN10025-2:2004 specification.

  3. Current Status of Development of High Nickel Low Alloy Steels for Commercial Reactor Pressure Vessel

    International Nuclear Information System (INIS)

    SA508 Gr.3 Mn-Mo-Ni low alloy steels have been used for nuclear reactor pressure vessel steels up to now. Currently, the design goal of nuclear power plant is focusing at larger capacity and longer lifetime. Requirements of much bigger pressure vessels may cause critical problems in the manufacturing stage as well as for the welding stage. Application of higher strength steel may be required to overcome the technical problems. It is known that a higher strength and fracture toughness of low alloy steels such as SA508 Gr.4N low alloy steel could be achieved by increasing the Ni and Cr contents. Therefore, SA508 Gr.4N low alloy steel is very attractive as eligible RPV steel for the next generation PWR systems. In this report, we propose the possibility of SA508 Gr.4N low alloy steel for an application of next generation commercial RPV, based on the literature research result about development history of the RPV steels and SA508 specification. In addition, we have surveyed the research result of HSLA(High Strength Low Alloy steel), which has similar chemical compositions with SA508 Gr.4N, to understand the problems and the way of improvement of SA508 Gr.4N low alloy steel. And also, we have investigated eastern RPV steel(WWER-1000), which has higher Ni contents compared to western RPV steel

  4. Current Status of Development of High Nickel Low Alloy Steels for Commercial Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Chul; Lee, B. S.; Park, S. G.; Lee, K. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-12-15

    SA508 Gr.3 Mn-Mo-Ni low alloy steels have been used for nuclear reactor pressure vessel steels up to now. Currently, the design goal of nuclear power plant is focusing at larger capacity and longer lifetime. Requirements of much bigger pressure vessels may cause critical problems in the manufacturing stage as well as for the welding stage. Application of higher strength steel may be required to overcome the technical problems. It is known that a higher strength and fracture toughness of low alloy steels such as SA508 Gr.4N low alloy steel could be achieved by increasing the Ni and Cr contents. Therefore, SA508 Gr.4N low alloy steel is very attractive as eligible RPV steel for the next generation PWR systems. In this report, we propose the possibility of SA508 Gr.4N low alloy steel for an application of next generation commercial RPV, based on the literature research result about development history of the RPV steels and SA508 specification. In addition, we have surveyed the research result of HSLA(High Strength Low Alloy steel), which has similar chemical compositions with SA508 Gr.4N, to understand the problems and the way of improvement of SA508 Gr.4N low alloy steel. And also, we have investigated eastern RPV steel(WWER-1000), which has higher Ni contents compared to western RPV steel.

  5. Microbial corrosion of high alloy steels in natural sea water

    International Nuclear Information System (INIS)

    The paper deals with an investigation into regularities of settlement and potential impact of microbial forms on the corrosion of 12Kh18N10T stainless steel depending on its microstructure. It is shown that inhomogeneity of the morphorological composition and quantitative distribution of microorganisms on the surface of alloyed steels is caused by the selectivity of bacterial cells settlement on the substrate structural elements. The corrosion destruction at microscopic level primarily starts in the zones of microorganism concentration. 19 refs.; 3 figs.; 2 tabs

  6. Thermodynamic Modeling as a Strategy for Casting High Alloy Steels

    Institute of Scientific and Technical Information of China (English)

    Peri Reddy V; S Raman Sankaranarayanan

    2009-01-01

    Strategies based on thermodynamic calculations can be used to overcome the problems associated with oxides encountered in steel plant operations, which can lead to certain difficulties in the process such as clogging of submerged entry nozzle during continuous casting. Approaches to producing high alloy steels by continuous casting have been taken. One of the strategies to avoid the oxidation of chromium is to add a small amount of other elements (subject to other constraints), which do not cause subsequent problems. The problem has been studied using the Thermo-CalcR software, with related databases; and the results obtained for different process conditions or generic com-positions have been presented.

  7. Preparation of ferritic 17%Cr ODS steel by mechanical alloying from prealloyed steel powder

    Czech Academy of Sciences Publication Activity Database

    Hadraba, Hynek; Husák, Roman; Kuběna, Ivo; Bureš, R.; Fáberová, M.; Strečková, M.

    2014-01-01

    Roč. 14, č. 4 (2014), s. 222-227. ISSN 1335-8987 R&D Projects: GA ČR(CZ) GA14-25246S Institutional support: RVO:68081723 Keywords : ODS steel * mechanical alloying * hot rolling Subject RIV: JG - Metallurgy

  8. Master alloy for manufacture of stainless and refractory steels and alloys

    International Nuclear Information System (INIS)

    The master alloy contains iron, 0.01 to 0.03% carbon, 0.1 to 2.0% manganese, 0.01 to 0.2% silicon, possibly impurities, such as traces of up to 0.015% sulphur, up to 0.01% phosphorus, 0.01%. nitrogen, 0.1% copper, up to 0.01% cobalt and traces of up to 0.05% arsenic, tin, lead, zinc or bismuth separate or in combination. The master alloy is used in the manufacture of steels and alloys for the chemical industry and for nuclear power. (B.S.)

  9. Testing and assessment of low alloy steel for marine application

    International Nuclear Information System (INIS)

    This paper is an account of the work carried out during the assessment of low alloy steel (WH-80) for marine application. The relevant acceptance criteria consulted during the process is DEFST AN 02-874 and a standard reference material. Assessment is based on the experimental results of the tests carried out for the steel. Testing comprised of mechanical (tensile, impact and hardness) tests, corrosion (immersion corrosion and stress corrosion cracking) tests, metallography test and weldability (weld joint strength, controlled thermal severity -CTS and Y -Groove) tests undertaken at various testing laboratories in Pakistan. The results obtained after testing have been compared with acceptance criteria (DEFSTAN 02-874 and standard reference material). Moreover results have been compared with contemporary steels used for marine applications. Results showed a reasonable agreement with results available in literature for other low alloy steels with respect to mechanical strength and weldability. Steel weldments qualified the weld joint strength tests and weldability tests. Toughness has been measured at various temperatures. Results revealed that the toughness of base metal is higher than heat affected zone (HAZ) and weld metal. In weldability tests, weld metal and HAZ were examined microscopically to investigate integrity of weld. No cracks have been observed in the weld which indicates complete diffusion in to the welding material. WH- 80 steel has exhibited comparatively high corrosion rate, reduction in tensile strength during SCC test and low Charpy energy values at -50 degree C. It is therefore concluded that the WH-80 steel is unsuitable for use in application at subzero (OC) temperatures and in highly corrosive environment. (author)

  10. Frictional conditions between alloy AA6060 aluminium and tool steel

    Science.gov (United States)

    Widerøe, Fredrik; Welo, Torgeir

    2011-05-01

    The frictional conditions in the new process of screw extrusion of aluminium have been investigated. The contact behaviour between the aluminum alloy and the tool steel in the extruder is vital for understanding the extrusion process. Using a compressive-rotational method for frictional measurements the conditions for unlubricated sticking friction between aluminum alloy AA6060 and tool steel at different combinations of temperatures and pressures have been investigated. In this method the samples in the form of disks are put under hydrostatic pressure while simultaneously being rotated at one end. Pins made from contrast material have been inserted into the samples to measure the deformation introduced. This approach along with 3D simulations form a method for determining the frictional conditions. The paper describes the test method and the results. It was found that the necessary pressure for sticking to occur between the aluminum AA6060 and the different parts of the extruder is heavily influenced by the temperature.

  11. Frictional conditions between alloy AA6060 aluminium and tool steel

    International Nuclear Information System (INIS)

    The frictional conditions in the new process of screw extrusion of aluminium have been investigated. The contact behaviour between the aluminum alloy and the tool steel in the extruder is vital for understanding the extrusion process. Using a compressive-rotational method for frictional measurements the conditions for unlubricated sticking friction between aluminum alloy AA6060 and tool steel at different combinations of temperatures and pressures have been investigated. In this method the samples in the form of disks are put under hydrostatic pressure while simultaneously being rotated at one end. Pins made from contrast material have been inserted into the samples to measure the deformation introduced. This approach along with 3D simulations form a method for determining the frictional conditions. The paper describes the test method and the results. It was found that the necessary pressure for sticking to occur between the aluminum AA6060 and the different parts of the extruder is heavily influenced by the temperature.

  12. Description Of Alloy Layer Formation On A Cast Steel Substrate

    Directory of Open Access Journals (Sweden)

    Szajnar J.

    2015-09-01

    Full Text Available A description of alloy layer formation on a steel substrate is presented. Two types of formation are considered: diffusion of carbon and chromium into the solid from the pad in the direction of the cast steel within the FeCrC (grains and diffusion in a layer of liquid chromium cast iron formed in a preceding step. The influence of silicon in the pad on the pad’s transformation into the liquid is also examined. Solidus and liquidus temperatures of high carbon ferrochromium are determined. The larger the content of Si is used in the experiment, the lower the solidus temperature of the FeCrC alloy is observed. This results from the higher intensity of the elements’ diffusion and faster formation of the liquid.

  13. 76 FR 67407 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Notice of Preliminary Results of Antidumping...

    Science.gov (United States)

    2011-11-01

    ... Alloy Steel Wire Rod from Mexico, (76 FR 45509 (July 29, 2011)). We preliminarily determine that, during... and Certain Alloy Steel Wire Rod from Mexico, 71 FR 27989 (May 15, 2006). Therefore, pursuant to... merchandise subject to this order is certain hot-rolled products of carbon steel and alloy steel, in coils,...

  14. 76 FR 16607 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Notice of Partial Rescission of Antidumping...

    Science.gov (United States)

    2011-03-24

    ... merchandise subject to this order is certain hot-rolled products of carbon steel and alloy steel, in coils, of... International Trade Administration Carbon and Certain Alloy Steel Wire Rod From Mexico: Notice of Partial... antidumping duty order on carbon and certain alloy steel wire rod from Mexico. See Antidumping...

  15. 75 FR 8650 - Carbon and Certain Alloy Steel Wire Rod from Trinidad and Tobago; Final Results of Antidumping...

    Science.gov (United States)

    2010-02-25

    ... this order is certain hot-rolled products of carbon steel and alloy steel, in coils, of approximately... International Trade Administration (A-274-804) Carbon and Certain Alloy Steel Wire Rod from Trinidad and Tobago... of the antidumping duty order on carbon and certain alloy steel wire rod from Trinidad and...

  16. 77 FR 13545 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Notice of Final Results of Antidumping Duty...

    Science.gov (United States)

    2012-03-07

    ... Changed Circumstances Review: Carbon and Certain Alloy Steel Wire Rod from Mexico, 76 FR 45509 (July 29... order is certain hot-rolled products of carbon steel and alloy steel, in coils, of approximately round... International Trade Administration Carbon and Certain Alloy Steel Wire Rod From Mexico: Notice of Final...

  17. Crystallisation mechanism of laser alloyed gradient layer on tool steel

    OpenAIRE

    M. Bonek; L.A. Dobrzański; M. Piec; E. Hajduczek; A. Klimpel

    2007-01-01

    Purpose: The objective of the present work was to study the modification of the microstructure of hot-work toolsteel X40CrMoV5-1 during the surface modifying by means of laser technology.Design/methodology/approach: The structural mechanism of surface layer development was determinedand the effect of alloying parameters and thickness of paste layer applied onto the steel surface on structurerefinement and influence of these factors on the crystallisation mechanism of surface layer was studied...

  18. Manifestations of DSA in austenitic stainless steels and inconel alloys

    International Nuclear Information System (INIS)

    The aim of the investigation was to examine and compare different types of DSA (Dynamic Strain Aging) manifestations in AISI 316 austenitic stainless steel (SS) and Inconel 600 and Inconel 690 alloys by means of slow strain rate tensile testing, mechanical loss spectrometry (internal friction) and transmission electron microscopy (TEM). Another aim was to determine differences in the resulting dislocation structures and internal friction response of materials showing and not showing DSA behaviour

  19. Corrosion of low alloy steels in natural seawater. Influence of alloying elements and bacteria

    International Nuclear Information System (INIS)

    Metallic infrastructures immersed in natural seawater are exposed to important corrosion phenomena, sometimes characterised as microbiologically influenced corrosion. The presence of alloying elements in low alloy steels could present a corrosion resistance improvement of the structures. In this context, tests are performed with commercial steel grades, from 0,05 wt pc Cr to 11,5 wt pc Cr. They consist in 'on site' immersion in natural seawater on the one hand, and in laboratory tests with immersion in media enriched with marine sulphide-producing bacteria on the other hand. Gravimetric, microbiological, electrochemical measurements and corrosion product analyses are carried out and show that corrosion phenomenon is composed of several stages. A preliminary step is the reduction of the corrosion kinetics and is correlated with the presence of sessile sulphide-producing bacteria and an important formation of sulphur-containing species. This phase is shorter when the alloying element content of the steel increases. This phase is probably followed by an increase of corrosion, appearing clearly after an 8-month immersion in natural seawater for some of the grade steels. Chromium and molybdenum show at the same time a beneficial influence to generalised corrosion resistance and a toxic effect on sulphide-producing bacteria. This multidisciplinary study reflects the complexity of the interactions between bacteria and steels; sulphide-producing bacteria seem to be involved in corrosion processes in natural seawater and complementary studies would have to clarify occurring mechanisms. (author)

  20. Dual Phase Heat Treatment of Low-Alloy Steel

    Institute of Scientific and Technical Information of China (English)

    HAN Jian-min; CUI Shi-hai; LI Wei-jing; MA Xiao-yan

    2005-01-01

    Dual phase heat treatment is an economical and effective way for improving the properties of low carbon steels and low-alloy steel materials. In this paper, the microstructures and mechanical properties of 20MnSi steel treated by different dual phase heat treatment have been studied. The results show that dual phase heat treatment with pre-quenching technique and then heating from room temperature to the critical zone can achieve finer and more homogeneous microstructure than that with pre-normalizing technique and then cooling from austenite zone to the critical zone. Among all factors affecting dual phase heat treatment, quenching temperature at the critical zone and tempering temperature play an important part in mechanical properties. Using proper dual phase heat treatment technique with computer-optimized parameters, the yield strength, the elongation and impact toughness of 20MnSi can reach 860 MPa, 16% and 207 MPa respectively.

  1. Neutron and deuteron irradiation creep in stainless steel alloys

    International Nuclear Information System (INIS)

    Irradiation rigs have been developed for HFR in Petten in which 49 specimens at a time can be irradiated in uniaxial tension. The creep elongations of AMCR type steels and of 20% cold-worked US 316 stainless steels were measured at intervals of irradiation for tensile stresses varying between 100 and 130 MPa and for temperatures between 350 and 4200C. Deuteron irradiation creep of 0.13 mm thick and 20% cold-worked 316 stainless steel alloys was investigated for an irradiation temperature of 3000C by means of a torsional creep facility installed at the Ispra Cyclotron. It was found that the creep rate increases linearly with the displacement rate in the range between 10-6 to 10-5 dpa.s-1. The stress dependence of the irradiation creep rate is quadratic for stresses between 50 and 100 MPa and linear for stresses ranging between 100 and 150 MPa

  2. Neutron and deuteron irradiation creep in stainless steel alloys

    International Nuclear Information System (INIS)

    Irradiation rigs have been developed for HFR in Petten in which 49 specimens at a time can be irradiated in uniaxial tension. The creep elongations of AMCR type steels and of 20% cold-worked US 316 stainless steels were measured at intervals of irradiation for tensile stresses varying between 100 and 130 MPa and or temperatures between 350 and 4200C. Deuteron irradiation creep of 0.13 mm thick and 20% cold-worked 316 stainless steel alloys was investigated for an irradiation temperature of 3000C by means of a torsional creep facility installed at the Ispra Cyclotron. It was found that the creep rate increases linearly with the displacement rate in the range between 10-6 to 10-5 dpa.s-1. The stress dependence of the irradiation creep rate is quadratic for stresses between 50 and 100 MPa and linear for stresses ranging between 100 and 150 MPa. (author)

  3. New alloys to conserve critical elements. [replacing chromium in steels

    Science.gov (United States)

    Stephens, J. R.

    1978-01-01

    Previous studies and surveys on availability of domestic reserves have shown that chromium is a most critical element within the U.S. metal industry. More precisely, the bulk of chromium is consumed in the production of stainless steels, specifically Type 304 stainless steel (304SS) which contains 18% Cr. The present paper deals with means of reducing chromium in commercial stainless steels by substituting more abundant or less expensive elements with the intent of maintaining the properties of 304SS. The discussion focuses on some of the oxidation and corrosion properties of new substitute stainless steels with only 12% Cr, which represents a potential saving of 33% of the chromium consumed in the production of 304SS. The alloying elements substituted for Cr in 304SS are selected according to their potential for protective oxide formation during high-temperature oxidation; these are Al, Si, Ti, Y, and misch metal which is 99.7% rare-earth metals containing 50 to 55% cerium. Other alloying elements to impart corrosion resistance are Mn, Mo, and V.

  4. Microstructural characterization of intercritically annealed low alloy PM steels

    Energy Technology Data Exchange (ETDEWEB)

    Gueral, A. [Materials Division, Technical Education Faculty, Metallurgy Education Department, Gazi University, 06500 Teknikokullar-Ankara (Turkey); Tekeli, S. [Materials Division, Technical Education Faculty, Metallurgy Education Department, Gazi University, 06500 Teknikokullar-Ankara (Turkey)]. E-mail: stekeli@gazi.edu.tr

    2007-07-01

    In this study, the applicability of intercritical annealing heat treatment, which is usually practiced to high strength low alloy ingot steels (HSLA), to low alloy powder metallurgy (PM) processed steels was investigated. With this heat treatment, it was intended to produce a dual-phase steel structure (ferrite + martensite) in PM steel. The effect of various amount of graphite addition on microstructure was also examined. For these purposes, atomized iron powder (Ancorsteel 1000) was mixed with 0.3 and 0.5 wt% graphite powder. The mixed powders were cold pressed at 700 MPa with single action and sintered at 1120 deg. C for 30 min under pure argon gas atmosphere. Some of the sintered specimens were directly annealed at intercritical heat treatment temperatures of 724, 735 and 760 deg. C and rapidly water quenched. Through these heat treatments, ferrite + martensite microstructure with coarse grain size were produced. The other sintered specimens were first austenitized at 890 deg. C for 12 min before intercritically annealing and then rapidly water quenched to produce fully martensitic structure. These specimens with fully martensitic microstructure were subsequently annealed at intercritical annealing temperatures of 724, 735 and 760 deg. C and rapidly water quenched. Ferrite + martensite microstructure with fine grain size was obtained by this route. The experimental results showed that martensite volume fraction increased with increasing intercritical annealing temperature as well as increasing graphite content. It is thought that mechanical properties of PM steels can be controlled by these heat treatments which are an alternative to traditional heat treatments of quenching + tempering applied usually to PM steels.

  5. High-strength low-alloy (HSLA) steels: Visokotrdna malolegirana (HSLA) konstrukcijska jekla:

    OpenAIRE

    Skobir Balantič, Danijela Anica

    2011-01-01

    Micro-alloyed, high-strength, low-alloy (HSLA) steels are important structural materials and contain small amounts of alloying elements, such as niobium, titanium, vanadium, and aluminium, which enhance the strength through the formation of stable carbides, nitrides or carbonitrides and have an effect on the hardenability. Such steels contain less than 0.1 % of the alloying additions, used individually or in combination. Yield strength increments of two or three times that of plain carbon-man...

  6. Superplastic solid state welding steel and copper alloy based on laser quenching of steel surface

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ke-ke; HAN Cai-xia; QUAN Shu-li; CHENG Guang-hui; YANG Jie; YANG Yun-lin

    2005-01-01

    Based on the feasibility of isothermal superplastic solid state welding of steel and copper alloy, the welded surface of steel surface was ultra-fined through laser quenching, and then the welding process tests between different base metals of 40Cr and QCr0.5 were made under the condition of non vacuum and non shield gas. The experimental results show that, with the sample surface of steel after laser quenching and that of copper alloy carefully cleaned, and under the pre-pressed stress of 56.6 -84.9 MPa, at the welding temperature of 750 -800 ℃ and at initial strain rate of (2.5 - 7.5) × 10-4 s-1 , the solid state welding can be finished in 120 - 180 s so that the strength of the joint is up to that of QCr0.5 base metal and the expansion rate of the joint does not exceed 6%. The plastic deformation of the joint was further analysed. The superplastic deformation of the copper alloy occurs in welding process and the deformation of steel are little.

  7. Experimental and Theoretical Investigations of Hot Isostatically Pressed-Produced Stainless Steel/High Alloy Tool Steel Compound Materials

    Science.gov (United States)

    Lindwall, Greta; Flyg, Jesper; Frisk, Karin; Sandberg, Odd

    2011-05-01

    Consolidation of tool steel powders and simultaneous joining to a stainless 316L steel are performed by hot isostatic pressing (HIP). Two tool steel grades are considered: a high vanadium alloyed carbon tool steel, and a high vanadium and chromium alloyed nitrogen tool steel. The boundary layer arising during diffusion bonding is in focus and, in particular, the diffusion of carbon and nitrogen over the joint. Measurements of the elemental concentration profiles and corrosion tests by the double loop-electrochemical potentiokinetic reactivation (DL-EPR) method are performed. Comparative calculations with the DICTRA software are performed and are found to be in agreement with the experimental results. It is found that the carbon tool steel grade has a more critical influence on the corrosion resistance of the stainless 316L steel in comparison to the nitrogen tool steel grade.

  8. Surface Nb-ALLOYING on 0.4C-13Cr Stainless Steel: Microstructure and Tribological Behavior

    Science.gov (United States)

    Yu, Shengwang; You, Kai; Liu, Xiaozhen; Zhang, Yihui; Wang, Zhenxia; Liu, Xiaoping

    2016-02-01

    0.4C-13Cr stainless steel was alloyed with niobium using double glow plasma surface alloying and tribological properties of Nb-alloyed steel such as hardness, friction and wear were measured. Effects of the alloying temperature on microstructure and the tribological behavior of the alloyed steel were investigated compared with untreated steel. Formation mechanisms of Nb-alloyed layers and increased wear resistance were also studied. The result shows that after surface Nb-alloying treatment, the 0.4C-13Cr steel exhibits a diffusion adhesion at the alloyed layer/substrate interface and improved tribological property. The friction coefficient of Nb-alloyed steel is decreased by about 0.3-0.45 and the wear rate after Nb-alloying is only 2-5% of untreated steel.

  9. Development of Zn50 Brazing Alloy for Joining Mild Steel to Mild Steel (SAE1018

    Directory of Open Access Journals (Sweden)

    S.C. Nwigbo

    2014-09-01

    Full Text Available This work has developed new brazing alloys for joining mild steel to mild steel (SAE1018 at a lower temperature. The alloys blends and error analysis were done by experimental design software (Design Expert 8.0.7.1. Design of experiments was done by Scheffe quadratic mixture method. The liquidus temperatures were predicted by calculation of phase diagrams of the alloying metals. The brazing alloys were produced by gravity technique and melted using silicon carbide graphite crucible. The quality of the brazing alloys was analyzed by optical microscopy (OM, atomic absorption spectroscopy (AAS and fourier transform infrared spectroscopy (FT-IR. Brazed joints were produced by torch method with a commercial flux. Brazing temperatures (liquidus were tracked by a digital infrared/laser pyrometer. Some mechanical properties studied were tensile strength and hardness. Finally, brazed joints produced from the developed brazing alloys were compared to that produced from muntz brass. Six (6 brazing alloys were successfully developed. Zinc and manganese were the main components, to which were added; 3 to 4 %wt silver and 11 to15 %wt modifying element. The microstructure showed a typical eutectic structure with zinc-rich phase distributed uniformly in the matrix with a combination of different sizes of dendrite, rounded blocks of compounds and hypoeutectic structures. AAS results indicated minimal out-gassing of zinc and FT-IR results indicated very low presence of atmospheric gas. The range of brazing temperature for best results was recorded from 690.90 to 735.10 0C. The joints produced from the developed brazing alloys had acceptable strengths with improved stress-strain behaviour compared to muntz brass.

  10. Current Developments of Alloyed Steels for Hot Strip Roughing Mills : Characterization of High-Chromium Steel and Semi-High Speed Steel

    OpenAIRE

    LECOMTE-BECKERS, Jacqueline; Sinnaeve, Mario; Tchuindjang, Jérôme Tchoufack

    2012-01-01

    Two alloys grades for work rolls used in the roughing stand of Hot Strip Mill - high chromium steel (HCS) and semi-high-speed steel (semi-HSS), In this paper, the new semi-high-speed steel grade is studied

  11. Application of nitrogen alloyed steels for Indian Fast Reactor programme

    International Nuclear Information System (INIS)

    Towards building fast reactors for fulfilling energy requirements through second stage of nuclear power program planned by Department of Atomic Energy, a 500 MWe Prototype Fast Breeder Reactor (PFBR) is under advanced stage of construction at Kalpakkam, a coastal site. Nitrogen alloyed types 304LN and 316LN austenitic Stainless Steels have been selected for out of core components except for the steam generator primarily due to inclusion in the design codes favourable effect of nitrogen on mechanical strength and sensitization, and excellent weldability. For the once through steam generator design selected from economics and safety, modified 9Cr-1 Mo (Gr 91) has been selected from inclusion in the design codes, adequate mechanical strength, sound industrial experience and carbon transfer considerations. The presentation highlights the application of nitrogen alloyed types 304LN and 316LN SS, as well as modified 9Cr-1Mo steel for PFBR, and the influence of increased nitrogen alloying on mechanical properties on SS 316L for application to future fast reactors. (author)

  12. Alloying element vaporization during laser spot welding of stainless steel

    International Nuclear Information System (INIS)

    Alloying element loss from the weld pool during laser spot welding of stainless steel was investigated experimentally and theoretically. The experimental work involved determination of work-piece weight loss and metal vapour composition for various welding conditions. The transient temperature and velocity fields in the weld pool were numerically simulated. The vaporization rates of the alloying elements were modelled using the computed temperature profiles. The fusion zone geometry could be predicted from the transient heat transfer and fluid flow model for various welding conditions. The laser power and the pulse duration were the most important variables in determining the transient temperature profiles. The velocity of the liquid metal in the weld pool increased with time during heating and convection played an increasingly important role in the heat transfer. The peak temperature and velocity increased significantly with laser power density and pulse duration. At very high power densities, the computed temperatures were higher than the boiling point of 304 stainless steel. As a result, evaporation of alloying elements was caused by both the total pressure and the concentration gradients. The calculations showed that the vaporization occurred mainly from a small region under the laser beam where the temperatures were very high. The computed vapour loss was found to be lower than the measured mass loss because of the ejection of tiny metal droplets owing to the recoil force exerted by the metal vapours. The ejection of metal droplets has been predicted by computations and verified by experiments

  13. Mechanism of Bainite Nucleation in Steel, Iron and Copper Alloys

    Institute of Scientific and Technical Information of China (English)

    Mokuang KANG; Ming ZHU; Mingxing ZHANG

    2005-01-01

    During the incubation period of isothermal treatment(or aging) within the bainitic transformation temperature range in a salt bath (or quenching in water) immediately after solution treatment, not only are the defects formed at high temperatures maintained, but new defects can also be generated in alloys, iron alloys and steels. Due to the segregation of the solute atoms near defects through diffusion, this leads to non-uniform distributions of solute atoms in the parent phase with distinct regions of both solute enrichment and solute depletion. It is proposed that when the Ms temperature at the solute depleted regions is equal to or higher than the isothermal (or aged) temperature,nucleation of bainite occurs within these solute depleted regions in the manner of martensitic shear. Therefore it is considered that, at least in steel, iron and copper alloy systems, bainite is formed through a shear mechanism within solute depleted regions, which is controlled and formed by the solute atoms diffusion in the parent phase.

  14. Hot Forging of Nitrogen Alloyed Duplex Stainless Steels

    Institute of Scientific and Technical Information of China (English)

    P.Chandramohan; S.S. Mohamed Nazirudeen; S.S. Ramakrishnan

    2007-01-01

    Duplex stainless steels are gaining global importance because of the need for a high strength corrosion resistant material. Three compositions of this group were selected with three different nitrogen contents viz, 0.15 wt pct (alloy 1), 0.23 wt pct (alloy 2) and 0.32 wt pct (alloy 3). The steels were melted in a high frequency induction furnace and hot forged to various reductions from 16% to 62%. In this work, the effect of hot forging on the ferrite content, hardness, yield strength, impact strength and grain orientation (texture) were studied. Fracture analysis on all the forged specimens using SEM reveals that a size reduction of 48% results in maximum ductility and impact strength as well as minimal ferrite content and grain size. Thus the mechanical properties are found to have a direct correlation to ferrite content and grain size. The highest impact strength was observed in specimens with the smallest grain size, which was observed in specimens forged to 48% reduction in size.

  15. Development of High Strength Low Alloy Steel for Nuclear Reactor Vessel

    International Nuclear Information System (INIS)

    SA508 Gr. 4N Ni-Cr-Mo low alloy steel has an improved strength and fracture toughness, compared to commercial low alloy steels such as SA508 Gr. 3 Mn-Mo-Ni low alloy steel. In this study, the microstructural observation and baseline test were carried out using SA508 Gr. 4N model alloy of 1 ton scale. Thermal embrittlement and neutron irradiation embrittlement behaviors of SA508 Gr. 4N model alloy were also evaluated. The yield strength of 540MPa, Charpy transition temperature, T41J of -132 .deg. C, Reference temperature, T0 of -146 .deg. C, and RTNDT of -105 .deg. C were obtained from large scale SA508 Gr. 3 low alloy steel. Effect of alloy elements on thermal embrittlement was carefully evaluated and embrittlement mechanism was characterized using small scale model alloys with various alloy composition. Neutron irradiation behavior at high fluence level up to 1.5x1020 n/cm2 corresponding over 80 years operation of RPV were investigated using irradiated samples from research reactor 'HANARO'. The irradiation embrittlement behavior of SA508 Gr. 4N model alloy was similar to that of commercial RPV steel. However, after neutron irradiation up to 1.3x1020 n/cm2, SA508 Gr. 4N model alloy shows lower transition temperature(T41J = -63 .deg. C) than unirradiated commercial RPV steel because it has a superior initial toughness

  16. 75 FR 69125 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China

    Science.gov (United States)

    2010-11-10

    ..., and by publishing the notice in the Federal Register on May 11, 2010 (75 FR 26273). The hearing was... COMMISSION Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China Determination... alloy steel standard, line, and pressure pipe (``seamless SLP pipe''), provided for in subheadings...

  17. 48 CFR 225.7011 - Restriction on carbon, alloy, and armor steel plate.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Restriction on carbon, alloy, and armor steel plate. 225.7011 Section 225.7011 Federal Acquisition Regulations System DEFENSE... on carbon, alloy, and armor steel plate....

  18. Compatibility of Austenitic Steel With Molten Lead-Bismuth-Tin Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui-qian; LI Yan; WANG Xiao-min

    2011-01-01

    The compatibility of the austenitic AISI 304 steel with Pb-Bi-Sn alloy was analyzed. The AISI 304 steels were immersed in stagnant molten Pb-33.3Bi-33. 3Sn alloy at 400, 500 and 600℃ for different exposure times (100-2 000 h) respectively. XRay diffractio

  19. 75 FR 21658 - Carbon and Certain Alloy Steel Wire Rod From Trinidad and Tobago

    Science.gov (United States)

    2010-04-26

    ... amended, 67 FR 68036 (Nov. 8, 2002). In accordance with sections 201.16(c) and 207.3 of the Commission's... COMMISSION Carbon and Certain Alloy Steel Wire Rod From Trinidad and Tobago AGENCY: United States... in the antidumping duty Investigation No. 731-TA-961 concerning carbon and certain alloy steel...

  20. The quality of the joint between alloy steel and unalloyed cast steel in bimetallic layered castings

    Directory of Open Access Journals (Sweden)

    T. Wróbel

    2012-01-01

    Full Text Available In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. ferritic-pearlitic unalloyed cast steel, whereas working part (layer is plate of austenitic alloy steel sort X2CrNi 18-9. The ratio of thickness between bearing and working part is 8:1. The aim of paper was assessed the quality of the joint between bearing and working part in dependence of pouring temperature and carbon concentration in cast steel. The quality of the joint in bimetallic layered castings was evaluated on the basis of ultrasonic non-destructive testing, structure and microhardness researches.

  1. Crack initiation mechanisms in IASCC of stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cookson, J.M.; Was, G.S. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering; Andresen, P.L. [GE Corporate Research and Development Labs., Schenectady, NY (United States)

    1995-12-31

    An abnormally high oxygen concentration was recently discovered in a high purity stainless steel alloy widely used in IASCC studies. This led to an investigation into the role of oxygen on the initiation of intergranular cracking in irradiated samples in high temperature water. The concentration of oxygen in the alloys correlated with the number of cracks initiated in the proton irradiated region of samples strained in water containing 0.5 {micro}S/cm H{sub 2}SO{sub 4} at 288 C. This suggests that the presence of oxygen, in the form of spinel oxide particles, can lead to a substantial increase in the likelihood of crack initiation. This effect is only observed in irradiated samples strained in water, not in either unirradiated (non-sensitized) samples strained in water or irradiated samples strained in argon This paper examines the possible role of oxides in promoting crack initiation and the implications for IASCC.

  2. Crack initiation mechanisms in IASCC of stainless steel alloys

    International Nuclear Information System (INIS)

    An abnormally high oxygen concentration was recently discovered in a high purity stainless steel alloy widely used in IASCC studies. This led to an investigation into the role of oxygen on the initiation of intergranular cracking in irradiated samples in high temperature water. The concentration of oxygen in the alloys correlated with the number of cracks initiated in the proton irradiated region of samples strained in water containing 0.5 microS/cm H2SO4 at 288 C. This suggests that the presence of oxygen, in the form of spinel oxide particles, can lead to a substantial increase in the likelihood of crack initiation. This effect is only observed in irradiated samples strained in water, not in either unirradiated (non-sensitized) samples strained in water or irradiated samples strained in argon This paper examines the possible role of oxides in promoting crack initiation and the implications for IASCC

  3. Alternative to Nitric Acid for Passivation of Stainless Steel Alloys

    Science.gov (United States)

    Lewis, Pattie L.; Kolody, Mark; Curran, Jerry

    2013-01-01

    Corrosion is an extensive problem that affects the Department of Defense (DoD) and National Aeronautics and Space Administration (NASA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. The DoD and NASA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and reduced operational cost. DoD and NASA agreed to collaborate to validate citric acid as an acceptable passivating agent for stainless steel. This paper details our investigation of prior work developing the citric acid passivation process, development of the test plan, optimization of the process for specific stainless steel alloys, ongoing and planned testing to elucidate the process' resistance to corrosion in comparison to nitric acid, and preliminary results.

  4. Creep equations for high-temperature steels and nickel alloys

    International Nuclear Information System (INIS)

    Phenomenological creep equations of a modified Garofalo type, including a description of plastic initial elongation and primary, secondary and tertiary creep can be applied to high-temperature steels and nickel base alloys for the whole range of temperatures, stresses, times and strains that is of practical interest. Deformation and damage under variable tensile pressure creep loads are described by constitutive 1D equations, which can be modelled on the basis of creep data from a phenomenological creep equation and can be integrated in a life prediction program

  5. Sorption of iodine on low-chromium-alloy steel

    International Nuclear Information System (INIS)

    The sorption behavior of iodine on the surfaces of 2 1/4% Cr-1% Mo steel was investigated as a part of the High Tmeperature Gas-Cooled Reactor (HTGR) Chemistry Program at Oak Ridge National Laboratory (ORNL). The primary objective of these tests was to determine the equilibrium sorptive capacity of this alloy, which comprises most of the cooler regions of HTGR coolant circuit, under representative conditions. The data will be used to improve the capability for predicting, with computer programs, iodine deposition as functions of temperature and location in the primary circuit

  6. 75 FR 22372 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's...

    Science.gov (United States)

    2010-04-28

    ... International Trade Administration Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe... determines that certain seamless carbon and alloy steel standard, line, and pressure pipe from the People's... imports of certain seamless carbon and alloy steel standard, line, and pressure pipe (``seamless...

  7. 75 FR 69050 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's...

    Science.gov (United States)

    2010-11-10

    ... International Trade Administration Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe... duty order on certain seamless carbon and alloy steel standard, line, and pressure pipe (``seamless... seamless pipe from the PRC. See Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure...

  8. 76 FR 36086 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-06-21

    ... Review: Certain Circular Welded Non-Alloy Steel Pipe and Tube from Mexico, 74 FR 41681 (August 18, 2009... Antidumping Duty Changed Circumstances Review: Certain Circular Welded Non-Alloy Steel Pipe from Mexico, 75 FR... Less Than Fair Value: Circular Welded Non- Alloy Steel Pipe From Mexico, 57 FR 42953 (September...

  9. Microstructure and properties of laser surface alloyed PM austenitic stainless steel

    OpenAIRE

    Z. Brytan; M. Bonek; L.A. Dobrzański

    2010-01-01

    Purpose: The purpose of this paper is to analyse the effect of laser surface alloying with chromium on the microstructural changes and properties of vacuum sintered austenitic stainless steel type AISI 316L (EN 1.4404).Design/methodology/approach: Surface modification of AISI 316L sintered austenitic stainless steel was carried out by laser surface alloying with chromium powder using high power diode laser (HPDL). The influence of laser alloying conditions, both laser beam power (between 0.7 ...

  10. [Analysis of alloy tool steel using X-ray fluorescence spectrometer].

    Science.gov (United States)

    Zhou, S; Cai, Y; Huang, Z

    2001-08-01

    This report briefly introduces the analysis of Mn, Cr, V, W, Ti, Nb, Co, Zr, Ni, Mo, S, P, Si and Cu in alloy tool steel with X-ray florescence spectrometer. After being polished with grinding well and being cleaned with ethly alcohol, the test samples can be directly measured, and the results agree well with the standard values of the laboratory standards. The precision of the method (RSD) is in the range of 0.13%-9.56% (n = 8) for all elements except W, Ti, Nb and Zr. The method can be applied to many kinds of steel, such as chrome vanadium steel, manganese steel, die steel, middle-low alloy steel, tool steel. The measure instrument should be rectified with two or three standard samples which the quantity contained is suitable. The standard samples include 1Cr18Ni9Ti, C17Ni2, 25CrMo1V, 30CrMnSiA, 3CrW8V, Gx-8, Cr12MoV, chrome vanadium steel, manganese-boron steel, middle-low alloy steel and other kinds of steel. If there is not conditions to make work curves for all kinds steel separately, sometimes we don't know what kind of steel for one complex sample, the more real way will be to make an overall work curves which contains more kinds of steel as far as possible. PMID:12945299

  11. Crystallisation mechanism of laser alloyed gradient layer on tool steel

    Directory of Open Access Journals (Sweden)

    M. Bonek

    2007-01-01

    Full Text Available Purpose: The objective of the present work was to study the modification of the microstructure of hot-work toolsteel X40CrMoV5-1 during the surface modifying by means of laser technology.Design/methodology/approach: The structural mechanism of surface layer development was determinedand the effect of alloying parameters and thickness of paste layer applied onto the steel surface on structurerefinement and influence of these factors on the crystallisation mechanism of surface layer was studied.Findings: Development of the surface layer was observed in which one can distinguish the remelted zone, heataffectedzone and the transient zone. The fine grained, dendritic structure occurs in the remelted and alloyedzone with the crystallization direction connected with the dynamical heat abstraction from the laser beaminfluence zone. The X40CrMoV5-1 conventionally heat treated steel was used as reference material.Practical implications: Laser surface modification has the important cognitive significance and gives grounds to thepractical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones.Originality/value: The outcome of the research is an investigation showing the structural mechanismsaccompanying laser alloying.

  12. Reactive Boride Brazing on Low-Alloy Automotive Grade Steel

    Science.gov (United States)

    Palanisamy, B.; Upadhyaya, A.

    2011-11-01

    Brazing is a widely used process to improve the performance of steels used in automotive applications. The substrate material is often exposed to harsh conditions in these applications and may affect the service life of the component. Reactive boride brazing aims to improve the mechanical properties of the substrate material by forming a ceramic-metal composite coating in a single-step process in situ. In this study, sintered Ancor 4300 low-alloy steel is used as the substrate with chromium-rich braze and chromium-lean braze materials. The mechanical properties of the brazed samples were studied in detail using microindentation hardness measurements and the transverse rupture test. The results indicate that the brazed superlayer has a 10 times higher hardness. There was a significant improvement in the transverse rupture strength of the steel brazed with the chromium-rich boride as compared to the pure substrate material. In an effort to reduce processing time, green compacts of the substrate were also directly brazed and yielded favorable results.

  13. Titanium-alloy enhances bone-pedicle screw fixation: mechanical and histomorphometrical results of titanium-alloy versus stainless steel

    OpenAIRE

    Christensen, F.B.; Dalstra, M.; Sejling, F.; Overgaard, S.; Bünger, C.

    2000-01-01

    Several types of pedicle screw systems have been utilized to augment lumbar spine fusion. The majority of these systems are made of stainless steel (Ss), but titanium-alloy (Ti-alloy) devices have recently been available on the market. Ti-alloy implants have several potential advantages over Ss ones. High bioactivity and more flexibility may improve bone ingrowth and mechanical fixation, and the material also offers superior magnetic resonance imaging (MRI) and computed tomography (CT) resolu...

  14. The abrasive wear behaviour of alloy cast steel in SiC-water slurry

    Directory of Open Access Journals (Sweden)

    R. Zapała

    2009-10-01

    Full Text Available The results of abrasive wear tests carried out in an environment of SiC-water slurry on four grades of cast steel, i.e. carbon cast steel with microadditions of vanadium, low-alloy L70H2GNM cast steel, and high-alloy L120G13 cast steels, without and with microadditions of vanadium, were discussed. Tests were carried out on a Miller machine. A measure of the abrasive wear resistance was the loss of mass in specimens during 16 hour test cycle. It has been proved that the L120G13 cast steel is definitely less resistant to abrasive wear than its L70H2GNM counterpart. On the other hand, no distinct differences in the abrasive wear resistance were noticed between the L120G13 cast steel without vanadium, and the L120G13 cast steel and carbon cast steel, both with microadditions of vanadium.

  15. Effect of amide type modified rapeseed oil as lubricating additive on friction and wear behavior of steel-steel and steel-aluminum alloy systems

    Institute of Scientific and Technical Information of China (English)

    FANG Jian-hua; CHEN Bo-shui; LIU Wei-min; DONG Lin; WANG Jiu

    2004-01-01

    A new type of environmentally friendly lube additive-amide type modified rapeseed oil was synthesized and characterized by infrared spectrum. Its effect on the friction and wear behavior of steel-steel and steel-aluminum alloy systems were investigated with a four-ball machine and an Optimol SRV friction and wear tester respectively.The morphographies of the worn surfaces were analyzed by means of scanning electron microscopy(SEM). The worn surfaces of the 2024Al alloy block were analyzed by means of X-ray photoelectron spectroscopy(XPS). The results show that the modified rapeseed oil as additives can obviously decrease the wear rate and friction coefficient of steel pair and steel-aluminum frictional pair. Its lubrication mechanism is inferred that a high strength complex protection films form on the worn surface of the Al alloy due to the adsorption or tribochemistry reaction of a long chain additive molecule and high reaction activity of N element.

  16. Effect of micro alloying elements on the interfacial reactions between molten aluminum alloy and tool steel

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, K.A. [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Shabestari, S.G. [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of)], E-mail: shabestari@iust.ac.ir

    2009-06-10

    The morphology and growth kinetics of intermetallic compounds that are formed in the interface of H13 tool steel and A380 molten aluminum has been investigated through immersion experiments. The effect of addition of micro alloying elements to the melt on the formation and thickness of intermetallic layer was also studied. Microstructural investigation showed that three intermetallic layers formed through the liquid-solid reaction during immersion of steel samples in the liquid aluminum at a temperature of 680 deg. C for the duration time of 2 min to 2.5 h. These intermetallic compounds are Al{sub 8}Fe{sub 2}Si, Al{sub 5}FeSi and Al{sub 12}Fe{sub 5}Si. The effect of nitride coating of the surface of H13 steel on the growth of intermetallic phases has also been studied. Micro alloying elements such as strontium and titanium have been used in the melt and their effects on the morphology of intermetallic compound and their growth rate have been investigated by the immersion experiments at the temperature of 680 deg. C for the time of 0.5-2.5 h. The results showed that two layers of Al{sub 8}Fe{sub 2}Si and Al{sub 5}FeSi formed at the interface and Al{sub 12}Fe{sub 5}Si layer was not observed. Nitride coating decreased the overall thickness of the intermetallic layer about 50% after immersion time of 0.5 h. Addition of micro alloying elements such as Sr (0.05 wt%) and Ti (0.2 wt%) to the melt decreased the total thickness of the intermetallic layer about 31% after immersion of steel for 0.5 h in the melt. Both nitride coating and addition of strontium (0.05 wt%) and titanium (0.2 wt%) micro alloying elements to the melt had the most influence on decreasing the overall thickness of the intermetallic layer. The thickness of the intermetallic layer decreased about 60% after immersion of steel for 2.5 h in the aluminum melt. The experimental results clearly indicate the beneficial effect of strontium on the kinetics of the formation and growth of the intermetallic layers.

  17. Effect of micro alloying elements on the interfacial reactions between molten aluminum alloy and tool steel

    International Nuclear Information System (INIS)

    The morphology and growth kinetics of intermetallic compounds that are formed in the interface of H13 tool steel and A380 molten aluminum has been investigated through immersion experiments. The effect of addition of micro alloying elements to the melt on the formation and thickness of intermetallic layer was also studied. Microstructural investigation showed that three intermetallic layers formed through the liquid-solid reaction during immersion of steel samples in the liquid aluminum at a temperature of 680 deg. C for the duration time of 2 min to 2.5 h. These intermetallic compounds are Al8Fe2Si, Al5FeSi and Al12Fe5Si. The effect of nitride coating of the surface of H13 steel on the growth of intermetallic phases has also been studied. Micro alloying elements such as strontium and titanium have been used in the melt and their effects on the morphology of intermetallic compound and their growth rate have been investigated by the immersion experiments at the temperature of 680 deg. C for the time of 0.5-2.5 h. The results showed that two layers of Al8Fe2Si and Al5FeSi formed at the interface and Al12Fe5Si layer was not observed. Nitride coating decreased the overall thickness of the intermetallic layer about 50% after immersion time of 0.5 h. Addition of micro alloying elements such as Sr (0.05 wt%) and Ti (0.2 wt%) to the melt decreased the total thickness of the intermetallic layer about 31% after immersion of steel for 0.5 h in the melt. Both nitride coating and addition of strontium (0.05 wt%) and titanium (0.2 wt%) micro alloying elements to the melt had the most influence on decreasing the overall thickness of the intermetallic layer. The thickness of the intermetallic layer decreased about 60% after immersion of steel for 2.5 h in the aluminum melt. The experimental results clearly indicate the beneficial effect of strontium on the kinetics of the formation and growth of the intermetallic layers.

  18. Economic stainless nitrided steels as an advanced substitute of light alloys

    International Nuclear Information System (INIS)

    Basic processing and mechanical properties of stainless steels with a structure of nitrogen-bearing martensite, in particular, steel type 0Kh16AN4B are under consideration. The advantages of such steels over light (aluminium, titanium) alloys in specific static and cyclic strength, hot and cold ductility, fracture toughness are revealed. Widespread manufacture of semiproducts and components of the steels at Russian metallurgical plants is considered to be actually possible

  19. Resistance of the alloy steel used in the fuel gas desulphurization installations

    International Nuclear Information System (INIS)

    The results have been presented of DC polarization and exposure investigations of alloy steels used as construction materials in flue gas desulphurization installations. on the base of analysis of composition of investigated steels and results of polarization studies, conditions have been discussed in which the pitting resistance equivalent (PRE) should be used. Among tested steels the significantly highest resistance to pitting corrosion is exhibited by 654SMO steel, classified as the super austenitic grade. (author). 14 refs, 3 figs, 2 tabs

  20. Highly alloyed stainless steels for sea water applications

    Energy Technology Data Exchange (ETDEWEB)

    Audouard, J.P.; Verneau, M. [Creusot-Loire Industrie, Le Creusot (France). Research Centre for Materials

    1996-10-01

    Natural sea water is known as a very aggressive environment which generates pitting and crevice corrosion on stainless steels. High chromium grades with sufficient molybdenum and nitrogen additions (PREN > 40) are generally recognized as resistant materials in natural sea water bu the material selection criteria must be improved to take into account the effect of climatic conditions and of biocide treatments which are widely used as anti-fouling agents in sea water circuits. The paper deals with the localized corrosion properties of conventional stainless steels (SS), duplex and superaustenitic alloys. The results of laboratory investigations conducted in more or less oxidizing chloride containing media are discussed. Then, immersion tests carried out in natural sea waters in different climatic conditions are presented and discussed. Finally, the effect of biocide addition on fouling and its consequences on corrosion is investigated. The results are interpreted taking into account the chemical composition of the stainless steels and biofilm criteria. The results showed the Mediterranean Sea to be slightly more aggressive than other European seas but a PREN value higher than 40 is sufficient for stainless steels to withstand localized corrosion in European natural sea waters. A residual chlorine level around 0.3--0.4 ppm was found to be very effective to limit the fouling and to avoid localized corrosion on SS. Nevertheless, due to difficulties in monitoring chlorine addition, PREN values higher than 50 are recommended to withstand localized corrosion in treated sea waters. As an example, the new super-austenitic grade 25Cr-22Ni-5.8Mo-1.5Cu-2W-0.45N with a PRENW value of 54 was found to be perfectly resistant to crevice corrosion with 0.5 ppm free chlorine at ambient temperature.

  1. Protective properties of epoxy coatings electrodeposited on steel electrochemically modified by Zn-Fe alloys

    OpenAIRE

    Bajat Jelena B.; Mišković-Stanković Vesna B.; Kačarević-Popović Zorica M.

    2004-01-01

    Epoxy coatings were electrodeposited on steel and steel modified by Zn-Fe alloys using the constant voltage method. Zn-Fe alloys were electrodeposited on steel at different current densities. The effect of the Zn-Fe alloy on the corrosion behavior of the epoxy coating was interpreted in terms of the electrochemical and transport properties. It was shown that the best properties, i.e. the largest values of the pore resistance and the smallest values of the coating capacitance, a longer period ...

  2. Temperature and environmentally assisted cracking in low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Auten, T.A.; Monter, J.V.

    1995-04-01

    Environmental assisted cracking (EAC) can be defined as the propagation of fatigue cracks in water at rates from 3 to over 40 times the growth rates in air. For low alloy steels with sulfur contents > 0.0125% by weight, EAC is normal behavior in the 240 to 290C range. However, literature yields mixed results for low alloy steels with compositions just below this sulfur level; some reports indicate EAC while others do not. Also, several authors have reported an increased tendency toward EAC when the water temperatures were lowered. In the present work, five ASTM A 508 Class 2 forgings with ladle and check analyses that ranged from 0.010 to 0.019 wt% S were tested in high purity deaerated water in the temperature range of 93 to 260C. At 260C these forgings did not exhibit EAC, reinforcing earlier results for two similar forgings. This broad sampling indicates strong resistance to EAC for this class of forging at 260C. On the other hand, EAC occurred consistently in the three of these forgings that were tested below 204C, provided the test conditions (loading frequency, {Delta}K, and R) were high enough to produce a high baseline fatigue crack growth rate (FCGR), where the baseline FCGR is that expected in air. At 149C, EAC occurred at test conditions that combined to yield a baseline FCGR greater than {approx}2E-6 mm/s. At 204, 121, and 93C, this critical crack growth rate appeared to shift to lower baseline values. The EAC that occurred at lower temperatures was a factor of 3 to 12 times higher than baseline air rates, which was not as strong as the effect for higher sulfur steels at 240 to 290C. Also, no plateau in the growth rates occurred as it does with the higher sulfur steels. In another approach, EAC was induced at 93 and at 260C by raising the dissolved oxygen content of the water from <10 to >15 ppb.

  3. Friction Welding of Aluminium and Aluminium Alloys with Steel

    Directory of Open Access Journals (Sweden)

    Andrzej Ambroziak

    2014-01-01

    Full Text Available The paper presents our actual knowledge and experience in joining dissimilar materials with the use of friction welding method. The joints of aluminium and aluminium alloys with the different types of steel were studied. The structural effects occurring during the welding process were described. The mechanical properties using, for example, (i microhardness measurements, (ii tensile tests, (iii bending tests, and (iv shearing tests were determined. In order to obtain high-quality joints the influence of different configurations of the process such as (i changing the geometry of bonding surface, (ii using the interlayer, or (iii heat treatment was analyzed. Finally, the issues related to the selection of optimal parameters of friction welding process were also investigated.

  4. Process to determine light elements content of steel and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Quintella, Cristina M.A.L.T.M.H.; Castro, Martha T.P.O. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica. LabLaser; Mac-Culloch, Joao N.L.M. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The present work reports a process to determine qualitatively and quantitatively elements of molar mass inferior to 23 within materials, by X rays spectra associated with multivariate data analysis, or chemometric analysis. The spectra is acquired between 5 keV and 22 keV when the materials are exposed to X radiation. Here is reported the direct determination of carbon content in steel and metallic alloys. The process is more effective when using spectral regions which are not usually used. From the analysis of these spectral regions which were not considered before, it was possible to detect light elements with molar mass lower than 23, which have low capacity of absorbing and emitting radiation, but have high capacity of scattering radiation. The process here reported has the advantage that X-Ray spectra obtained are calibrated multivariately, showing high potential for development in order to be used in a portable field equipment. (author)

  5. Programme for analysis of high alloy steel with emission spectrometer 'SPECTROLAB M3'

    International Nuclear Information System (INIS)

    The programme for analysis of high alloy steel is necessary addition to the programme for low and middle alloy steel which exists in almost every emission spectrometer of this type. It is now possible to determine the chemical composition of the most wide-spread kinds of steel by spectrometer without using another device. The corresponding standard samples for spectrometric analysis of the examined kinds of steel are used. The calibration curves for the analysed elements are built and the influence of the disturbing elements is established. The type and the value of the corrections eliminating this influence are determined. An estimation of the accuracy of the analysis is made. (author)

  6. Development of High Strength Low Alloy Steel for Nuclear Reactor Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, B. S.; Kim, M. C.; Yoon, J. H; Choi, K. J.; Kim, J. M.; Hong, J. H.

    2013-11-15

    SA508 Gr. 4N Ni-Cr-Mo low alloy steel has an improved strength and fracture toughness, compared to commercial low alloy steels such as SA508 Gr. 3 Mn-Mo-Ni low alloy steel. In this study, the microstructural observation and baseline test were carried out using SA508 Gr. 4N model alloy of 1 ton scale. Thermal embrittlement and neutron irradiation embrittlement behaviors of SA508 Gr. 4N model alloy were also evaluated. The yield strength of 540MPa, Charpy transition temperature, T{sub 41J} of -132 .deg. C, Reference temperature, T{sub 0} of -146 .deg. C, and RT{sub NDT} of -105 .deg. C were obtained from large scale SA508 Gr. 3 low alloy steel. Effect of alloy elements on thermal embrittlement was carefully evaluated and embrittlement mechanism was characterized using small scale model alloys with various alloy composition. Neutron irradiation behavior at high fluence level up to 1.5x10{sup 20} n/cm{sup 2} corresponding over 80 years operation of RPV were investigated using irradiated samples from research reactor 'HANARO'. The irradiation embrittlement behavior of SA508 Gr. 4N model alloy was similar to that of commercial RPV steel. However, after neutron irradiation up to 1.3x10{sup 20} n/cm{sup 2}, SA508 Gr. 4N model alloy shows lower transition temperature(T{sub 41J} = -63 .deg. C) than unirradiated commercial RPV steel because it has a superior initial toughness.

  7. Boric acid corrosion of carbon and low alloy steels

    International Nuclear Information System (INIS)

    Leakage of borated water from the reactor coolant system of pressurized water reactors (PWRs) and the resulting corrosion of carbon and low alloy steel components are concerns that have been addressed by utilities for many years. Significant corrosion has been observed in instances where such leakage has gone undetected for several months. In 1990, the B and W Owners Group (B and WOG) sponsored a test program to determine the levels of wastage that are possible when primary water leakage occurs. In this test program, carbon and stainless steel specimens were exposed to borated water at temperatures from 300 F to 550 F. Initial boric acid concentration was controlled within the limits of 13,000 to 15,000 ppm (as H3BO3) with 1.0--2.0 ppm lithium (as LiOH) added to duplicate the primary water chemistry. Testing was performed to determine the degree of attack caused by a leak traveling along a pipe both with and without insulation. These tests show the importance of temperature and boric acid concentrations on the wastage that can occur from such a leak

  8. Alloys influence in ferritic steels with hydrogen attack

    International Nuclear Information System (INIS)

    Materials exposed to a corrosive environment and high temperatures, are associated with a decrease of their mechanical properties and embitterment.At room temperatures atomic hydrogen diffuses easily through metals structure, it accumulates in lattice defects forming molecular hydrogen and generating cracking due to internal stresses.Under high temperatures the phenomenon is more complex.The steels in these conditions present different structures of precipitates, that the change under creep conditions period.In this work it is determined the influence of Cr and V alloys, the changes of ferritic steel resistance in a corrosive environment and high temperatures.1.25 Cr 1 Mo 0.25 V and 2.25Cr 1 Mo under different loads and temperatures previously attacked by hydrogen environment.The hydrogen is induced by the electrolytic technique, optimizing the choice of temperatures, current density, electrolyte, etc. In order to control an adequate cathode charge, a follow up procedure is carried out by electronic barrier microscopy.After the attack, the material is settled at room temperatures for certain period of time, to allow the hydrogen to leave and evaluate the residual damage.Creep by torsion assays, under constant load and temperature is used as an experimental technique.With the outcome data curves are drawn in order to study the secondary creep rate, with the applied load and temperature, determining the value of stress exponent n and the activation energy Q.Comparing to equal assays to the same ferritic steels but non attacked by hydrogen, these values allows the prediction of microstructure changes present during these tests

  9. Regularities of structure formation during hot deformation of austenite in alloy steels

    International Nuclear Information System (INIS)

    Regularities of substructure formation during hot working of austenite in 110Kh6 and 40Kh8G8 alloy steels, structural peculiarities and relations between structure development and a hot deformation curve were investigated. The possibility of structure formation modeling is also evaluated for deformation under commercial procedure conditions. Hot deformation during high temperatue thermomechanical treatment was carried out by rolling and compression. It is found that in alloy steel austenite during hot deformation up to 7-10% the processes of intensive strain hardening develop which result in formation of substructure with high density of dislocations either distributed uniformly or forming a cellular type substructure. Strain softening processes (dynamic polygonization) arise with a deformation degree increase. The relationship found between a hot deformation curve and structural changes during hot working of alloy steel austenite provides the option for conditions of high temperature thermomechanical treatment of commerical alloy steels softening according to a dynamic polygonization mechanism

  10. Nanosized controlled surface pretreatment of biometallic alloy 316L stainless steel.

    Science.gov (United States)

    Abdel-Fattah, Tarek M; Loftis, Derek; Mahapatro, Anil

    2011-12-01

    Stainless steel (AISI 316L) is a medical grade stainless steel alloy used extensively in medical devices and in the biomedical field. 316L stainless steel was successfully electropolished via an ecologically friendly and biocompatible ionic liquid (IL) medium based on Vitamin B4 (NB4) and resulting in nanosized surface roughness and topography. Voltammetry and chronoamperometry tests determined optimum polishing conditions for the stainless steel alloy while atomic force microscopy (AFM) and scanning electron microscopy (SEM) provided surface morphology comparisons to benchmark success of each electropolishing condition. Energy dispersive X-ray analysis (EDX) combined with SEM revealed significantly smoother surfaces for each alloy surface while indicating that the constituent metals comprising each alloy effectively electropolished at uniform rates. PMID:22416578

  11. Static Recrystallization Behavior of Hot Deformed Austenite for Micro-Alloyed Steel

    Institute of Scientific and Technical Information of China (English)

    Jie HUANG; Zhou XU; Xin XING

    2003-01-01

    Static recrystallization behavior of austenite for micro-alloyed steel during hot rolling was studied and the influence (τ-ε diagram) of holding time and deformation at different deformations and isothermal temperatures on microstructuralstate of austen

  12. Crack-Growth Behavior of Laser Surface-Alloyed Low-Carbon Steel

    Science.gov (United States)

    Šturm, Roman; Žnidaršič, Matjaž; Grum, Janez

    2013-09-01

    Crack-growth behavior of Nd:YAG laser surface-alloyed as-received low-carbon steel Fe360B was evaluated. Thin surface layer was alloyed with silicon carbide SiC. During laser surface alloying process SiC powder dissolved in the melted pool. The surface-alloyed layer had as-solidified structure composed mainly of dendrites of ferrite, fine martensite needles, and retained austenite. The micro-hardness of the laser surface-alloyed layer was about 850 HV0.1. In laser surface-alloyed layer compressive residual stresses of average amount of σ RS = -100 MPa were obtained. In crack-growth tests comparison between specimens of as-received low-carbon steel Fe360B and the same steel with laser-alloyed surface was made. As the crack propagation was perpendicular to the interface between the laser-alloyed layers and the base metal, laser surface-alloyed specimens exhibited higher crack-growth resistance in the low stress intensity factor range Δ K th than as-received steel specimens.

  13. Galvanic Interaction between Chalcopyrite and Pyrite with Low Alloy and High Carbon Chromium Steel Ball

    Directory of Open Access Journals (Sweden)

    Asghar Azizi

    2013-01-01

    Full Text Available This study was aimed to investigate the galvanic interaction between pyrite and chalcopyrite with two types of grinding media (low alloy and high carbon chromium steel ball in grinding of a porphyry copper sulphide ore. Results indicated that injection of different gases into mill altered the oxidation-reduction environment during grinding. High carbon chromium steel ball under nitrogen gas has the lowest galvanic current, and low alloy steel ball under oxygen gas had the highest galvanic current. Also, results showed that the media is anodic relative to pyrite and chalcopyrite, and therefore pyrite or chalcopyrite with a higher rest potential acted as the cathode, whilst the grinding media with a lower rest potential acted as the anode, when they are electrochemically contacted. It was also found that low alloy steel under oxygen produced the highest amount of EDTA extractable iron in the slurry, whilst high carbon chromium steel under nitrogen atmosphere led to the lowest amount.

  14. Design of a low-alloy high-strength and high-toughness martensitic steel

    Science.gov (United States)

    Zhao, Yan-jun; Ren, Xue-ping; Yang, Wen-chao; Zang, Yue

    2013-08-01

    To develop a high strength low alloy (HSLA) steel with high strength and high toughness, a series of martensitic steels were studied through alloying with various elements and thermodynamic simulation. The microstructure and mechanical properties of the designed steel were investigated by optical microscopy, scanning electron microscopy, tensile testing and Charpy impact test. The results show that cementite exists between 500°C and 700°C, M7C3 exits below 720°C, and they are much lower than the austenitizing temperature of the designed steel. Furthermore, the Ti(C,N) precipitate exists until 1280°C, which refines the microstructure and increases the strength and toughness. The optimal alloying components are 0.19% C, 1.19% Si, 2.83% Mn, 1.24% Ni, and 0.049% Ti; the tensile strength and the V notch impact toughness of the designed steel are more than 1500 MPa and 100 J, respectively.

  15. Interfacial study of semi-solid aluminum alloy and stainless steel sheathed extrusion

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-wei; GUO Cheng; LIU Xu-feng; SHAO Guang-jie

    2006-01-01

    Using sheathed extrusion technique, the bonding and forming of semi solid aluminum alloy with stainless steel sheath are successfully realized. The relationship between the interfacial shear strength and the solid fraction of semi solid aluminum alloy at different extrusion ratios is analyzed; the interfacial and fracture structure of the sheath material are studied by optical microscopy(OM) and scanning electric microscopy(SEM). The result shows that interfacial shear strength increases with the increase of extrusion ratio, the maximum value of the interfacial shear strength is obtained when solid fraction of aluminum alloy is 30%,solid phase and liquid phase of the semi solid aluminum alloy are bonded with stainless steel by turns along the interface, and the aluminum alloy can not be peeled from the stainless steel completely, which means nicer bonding occurs at the interface.

  16. Industrial Experience on the Caustic Cracking of Stainless Steels and Nickel Alloys - A Review

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B

    2005-10-09

    Caustic environments are present in several industries, from nuclear power generation to the fabrication of alkalis and alumina. The most common material of construction is carbon steel but its application is limited to a maximum temperature of approximately 80 C. The use of Nickel (Ni) alloys is recommended at higher temperatures. Commercially pure Ni is the most resistant material for caustic applications both from the general corrosion and the stress corrosion cracking (SCC) perspectives. Nickel rich alloys also offer a good performance. The most important alloying elements are Ni and chromium (Cr). Molybdenum (Mo) is not a beneficial alloying element and it dissolves preferentially from the alloy in presence of caustic environments. Austenitic stainless steels such as type 304 and 316 seem less resistant to caustic conditions than even plain carbon steel. Experimental evidence shows that the most likely mechanism for SCC is anodic dissolution.

  17. Effect of inter-critical quenching on mechanical properties of casting low-alloy steel

    OpenAIRE

    Liu Zhongli; Shang Yong

    2013-01-01

    For some casting low-alloy steels, traditional quenching and tempering heat treatments can improve the strength; however, sometimes the ductility is not satisfied. Therefore, some kind of effective heat treatment method seems necessary; one which could improve the ductility, but not seriously affect the strength. In this paper, the effect of inter-critical quenching (IQ) on the mechanical properties of casting low-alloy steel was studied. IQ was added between quenching and tempering heat trea...

  18. Microstructure and mechanical properties of a new type of austempered boron alloyed high silicon cast steel

    OpenAIRE

    Chen Xiang; Li Yanxiang

    2013-01-01

    In the present paper, a new type of austempered boron alloyed high silicon cast steel has been developed, and its microstructures and mechanical properties at different temperatures were investigated. The experimental results indicate that the boron alloyed high silicon cast steel comprises a dendritic matrix and interdendritic eutectic borides in as-cast condition. The dendritic matrix is made up of pearlite, ferrite, and the interdendritic eutectic boride is with a chemical formula of M2B (...

  19. Neutron irradiation test of copper alloy/stainless steel joint materials

    OpenAIRE

    山田 弘一; 河村 弘

    2006-01-01

    As a study about the joint technology of copper alloy and stainless steel for utilization as cooling piping in International Thermonuclear Experimental Reactor (ITER), Al2O3-dispersed strengthened copper or CuCrZr was joined to stainless steel by three kinds of joint methods (casting joint, brazing joint and friction welding method) for the evaluation of the neutron irradiation effect on joints. A neutron irradiation test was performed to three types of joints and each copper alloy. The avera...

  20. Comparison of Channel Segregation Formation in Model Alloys and Steels via Numerical Simulations

    Science.gov (United States)

    Cao, Y. F.; Chen, Y.; Li, D. Z.; Liu, H. W.; Fu, P. X.

    2016-06-01

    In the current study, the evolutions of channel segregations in several alloy systems, such as the typically used model alloys ( e.g., Ga-In, Sn-Pb, Sn-Bi, Al-Cu, and Ni-based superalloy) and some special steels, are numerically simulated in a cavity solidified unidirectionally. The simulations are based on a modified continuum macrosegregation model with an extension to the multicomponent systems. The results of model alloys and steels indicate that when the thermosolutal convection is strong enough, flow instability occurs, which in turn destabilizes the mushy zone. Subsequently, the channel segregation forms with the continuous interaction between solidification and flow. The formation behavior and severity of channel segregations in various systems are different owing to their distinct melt convection strengths and solidification natures. In the current simulations, channels are apparent for model alloys with high content of solutes, whereas they are slight in some special steels, such as 27SiMn steel, and totally disappear in carbon steels. These occurrence features of channel segregation in simulations of steels are consistent with the analyses by a modified Rayleigh number associated with alloying elements, and both outcomes are well supported by the fully sectioned steel ingots in experiments.

  1. The Influence of Post Weld Heat Treatment in Alloy 82/182 Dissimilar Metal Weld between Low Alloy Steel and 316L Stainless Steel

    International Nuclear Information System (INIS)

    Dissimilar metal welds (DMWs) using an Alloy 82/182 are widely used to join low alloy steel components and stainless steel pipes in pressurized water reactors (PWRs). It has been reported that tensile residual stress would be generated within DMWs during the welding processes. It is thought as main reason for primary water stress corrosion cracking (PWSCC) resulting in deterioration of long-term integrity. The application of post weld heat treatment (PWHT) has been considered to reduce the tensile residual stress after welding process. Meanwhile, the PWHT could affect the changes in microstructure, mechanical properties, and corrosion resistance. Therefore, in this study, the effects of PWHT on the microstructure, mechanical properties and corrosion behaviors of base metals of low alloy steel and stainless steel and welding materials of Alloy 82/182 are evaluated. The influence of PWHT in DMW has been investigated. SA 508 and 316L SS exhibited tempered bainite and austenitic grains with a few residual stringer type ferrite. Grain boundary carbides are not precipitated owing to low carbon and insufficient exposure time in 316L SS. The change of mechanicals properties in base metals is not observed. In case of Alloy 182, after PWHT, grain boundaries are covered with film-like continuous Cr-rich carbides

  2. Influence of alloying elements and nitrogen content on deformation resistance of chromium-nickel stainless steels

    International Nuclear Information System (INIS)

    Four groups of steels with a type Kh20N15 matrix differing in the contents of nitrogen and additional alloying element (Cu, Si, V or Nb) were studied for the influence of the alloying system on deformation resistance in hot rolling. The one-pass rolling was carried out at 900, 1000, 1100 and 1200 deg C with 20, 40 and 60 % reductions. Experimental data statistical processing showed that vanadium alloying results in a sharp increase of nitrogen content influence comparable with strain hardening. The hardening effect in copper- and silicon-containing alloys almost is independent of nitrogen concentration. Niobium-containing alloys lie between two above mentioned groups

  3. Design and identification of high performance steel alloys for structures subjected to underwater impulsive loading

    Science.gov (United States)

    Wei, Xiaoding; Latourte, Felix; Feinberg, Zack; Olson, Gregory; Espinosa, Horacio; Micro; Nanomechanics Laboratory Team; Olson Group Team

    2011-06-01

    To characterize the performance of naval structures, underwater blast experiments have been developed. Martensitic and austenitic steel alloys were designed to optimize the performance of structures subjected to impulsive loads. The deformation and fracture characteristics of the designed steel alloys were investigated experimentally and computationally. The experiments were based on an instrumented fluid structure interaction apparatus, in which deflection profiles were recorded. The computational study was based on a modified Gurson damage model able to accurately describe ductile failure under various loading paths. The model was calibrated for two high performance martensitic steels (HSLA-100 and BA-160) and an austenitic steel (TRIP-120). The martensitic steel (BA-160) was designed to maximize strength and fracture toughness while the austenitic steel (TRIP-120) was designed to maximize uniform ductility. The combined experimental-computational approach provided insight into the relationships between material properties and blast resistance of structures.

  4. RBF-Type Artificial Neural Network Model Applied in Alloy Design of Steels

    Institute of Scientific and Technical Information of China (English)

    YOU Wei; LIU Ya-xiu; BAI Bing-zhe; FANG Hong-sheng

    2008-01-01

    RBF model, a new type of artificial neural network model was developed to design the content of carbon in low-alloy engineering steels. The errors of the ANN model are. MSE 0. 052 1, MSRE 17. 85%, and VOF 1. 932 9. The results obtained are satisfactory. The method is a powerful aid for designing new steels.

  5. 77 FR 54926 - Certain Seamless Carbon and Alloy Steel; Standard, Line, and Pressure Pipe From Germany

    Science.gov (United States)

    2012-09-06

    ... FR 19711) and determined on July 6, 2012, that it would conduct an expedited review (77 FR 42763... COMMISSION Certain Seamless Carbon and Alloy Steel; Standard, Line, and Pressure Pipe From Germany... steel standard, line, and pressure pipe from Germany would be likely to lead to continuation...

  6. Friction Stir Lap Welding of Magnesium Alloy to Steel: A Preliminary Investigation

    Science.gov (United States)

    Jana, S.; Hovanski, Y.; Grant, G. J.

    2010-12-01

    An initial study was made to evaluate the feasibility of joining magnesium alloy AZ31 sheet to galvanized steel sheet in a lap configuration using friction stir welding (FSW). Two different automotive sheet steels were used for comparative evaluation of the dissimilar joining potential: a 0.8 mm thick, electrogalvanized (EG) mild steel, and a 1.5 mm thick hot-dipped galvanized (HDG) high-strength, low-alloy (HSLA) steel. These steels were joined to 2.33 mm thick AZ31B magnesium sheet. A single FSW tool design was used for both dissimilar welds, and the process parameters were kept the same. The average peak load for the AZ31-1.5 mm steel weld joint in lap shear mode was found to be 6.3 ± 1.0 kN. For the AZ31-0.8 mm steel weld, joint strength was 5.1 ± 1.5 kN. Microstructural investigation indicates melting of the Zn coating present on the steel sheets, and subsequent alloying with the Mg sheet resulted in the formation of a solidified Zn-Mg alloy layer.

  7. Friction Stir Lap Welding of Magnesium Alloy to Steel: A Preliminary Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Saumyadeep; Hovanski, Yuri; Grant, Glenn J.

    2010-12-01

    An initial study was made to evaluate the feasibility of joining Magnesium alloy AZ31 sheet to galvanized steel sheet in lap configuration using friction stir welding (FSW). Two different automotive sheet steels were used for comparative evaluation of the dissimilar joining potential; a 0.8mm thick, electro galvanized (EG) mild steel, and a 1.5mm thick hot dipped galvanized (HDG) high-strength, low-alloy steel (HSLA). These steels were joined to 2.33mm thick AZ31B magnesium sheet. A single FSW tool design was used for both dissimilar welds, and process parameters were kept the same. Average peak load for the AZ31-1.5 mm steel weld joint in lap shear mode was found to be 6.3 ± 1.0 kN. For the AZ31-0.8 mm steel weld, joint strength was 5.1 ± 1.5 kN. Microstructural investigation indicates melting of the Zn coating at the interface and subsequent alloying with the Mg sheet resulting in formation of solidified Zn-Mg alloy layer at AZ31/steel interface.

  8. Crystallization of Low-alloyed Construction Cast Steel Modified with V and Ti

    Directory of Open Access Journals (Sweden)

    A. Studnicki

    2013-07-01

    Full Text Available In this paper crystallization studies of low-alloyed construction cast steel were presented for different additions of chromium, nickel and molybdenum modified with vanadium and titanium. Studies were conducted using developed TDA stand, which additionally enabled evaluation of cooling rate influence on crystallization process of investigated alloys.

  9. Tensile and impact behaviour of BATMAN II steels, Ti-bearing reduced activation martensitic alloys

    Science.gov (United States)

    Filacchioni, G.; Casagrande, E.; De Angelis, U.; De Santis, G.; Ferrara, D.; Pilloni, L.

    Two series of Reduced Activation Ferrous alloys (RAF) have been produced and studied by Casaccia's Laboratories. These martensitic alloys are named BATMAN steels. They are among the few presently developed RAF materials to exploit Ti as a carbide forming and grain size stabilizing element instead of Ta. In this work their mechanical properties are illustrated.

  10. Effect of tempering temperature on the properties of low-alloy cast steel

    Directory of Open Access Journals (Sweden)

    D. Bartocha

    2011-07-01

    Full Text Available The mechanical properties of cast steel are primarily a function of chemical composition and solidification conditions i.e. primary structure, however, them can be change in a limited extent, by heat treatment. In the article the influence parameters of quenching on mechanical properties of low-alloy structural cast steel, modeled in terms of chemical composition, on the cast steel L20HGSNM, are presented. An attempt to quantify this relationship was made.

  11. Microstructure and properties of laser surface alloyed PM austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    Z. Brytan

    2010-05-01

    Full Text Available Purpose: The purpose of this paper is to analyse the effect of laser surface alloying with chromium on the microstructural changes and properties of vacuum sintered austenitic stainless steel type AISI 316L (EN 1.4404.Design/methodology/approach: Surface modification of AISI 316L sintered austenitic stainless steel was carried out by laser surface alloying with chromium powder using high power diode laser (HPDL. The influence of laser alloying conditions, both laser beam power (between 0.7 and 2.0 kW and powder feed rate (1.0-4.5 g/min at constant scanning rate of 0.5m/min on the width of alloyed surface layer, penetration depth, microstructure evaluated by LOM, SEM x-ray analysis, surface roughness and microhardness were presented.Findings: The microstructures of Cr laser alloyed surface consist of different zones, starting from the superficial zone rich in alloying powder particles embedded in the surface; these particles protrude from the surface and thus considerably increase the surface roughness. Next is alloyed zone enriched in alloying element where ferrite and austenite coexists. The following transient zone is located between properly alloyed material and the base metal and can be considered as a very narrow HAZ zone. The optimal microstructure homogeneity of Cr alloyed austenitic stainless steel was obtained for powder feed rate of 2.0 and 4.5 g/min and laser beam power of 1.4 kW and 2 kW.Practical implications: Laser surface alloying can be an efficient method of surface layer modification of sintered stainless steel and by this way the surface chromium enrichment can produce microstructural changes affecting mechanical properties.Originality/value: Application of high power diode laser can guarantee uniform heating of treated surface, thus uniform thermal cycle across treated area and uniform penetration depth of chromium alloyed surface layer.

  12. Sintered stainless steel surface alloyed with Si3N4 powder

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2011-07-01

    Full Text Available Purpose: The goal of this study was to investigate effects of laser surface alloying with Si3N4 powder on the microstructural changes and properties of vacuum sintered stainless steels, both austenitic X2CrNi17-12-2, ferritic X6Cr13 and duplex X2CrNiMo22-8-2.Design/methodology/approach: High power diode laser (HPDL was applied to surface modification of sintered stainless steels with Si3N4 powder. The influence of laser alloying conditions on the width, penetration depth of alloyed surface layer were studied and analysed via FEM simulation. The microstructure of alloyed layers was examined using light and scanning electron microscopy as well as X-ray diffraction. The microhardness and wear resistance of studied surface layers were also evaluated.Findings: The hardness increased with addition of Si3N4 due to strong solution hardening effect of nitrogen and silicon that dissolved in the steel matrix during laser alloying. The strong austenite stabilizer effect of nitrogen was observed in ferritic stainless steel that revealed duplex microstructure. The hardness increased with addition of Si3N4 due to strong solution hardening effect of nitrogen and silicon dissolved in the steel matrix during laser alloying. The hardening effect of Si3N4 was strongest in case of ferritic stainless steel where microhardness increased to 450 HV0.1 for 2.1 kW of laser beam power. The duplex stainless steel shows the regular microhardness on the whole penetration depth. Laser surface alloying with Si3N4 improved wear resistance of sintered stainless steels compared to not processed stainless steel as well as comparing layers prepared as machined grooves and surface with pre-coated paste.Practical implications: Laser surface alloying with Si3N4 powder can be an efficient method of surface layer hardening of sintered stainless steels and produce improvement of surface layer properties in terms of hardness and wear resistance. Moreover, application of high power diode

  13. Fatigue of carbon and low-alloy steels in LWR environments

    International Nuclear Information System (INIS)

    Fatigue tests have been conducted on A106-Gr B carbon steel and A533-Gr B low-alloy steel to evaluate the effects of an oxygenated-water environment on the fatigue life of these steels. For both steels, environmental effects are modest in PWR water at all strain rates. Fatigue data in oxygenated water confirm the strong dependence of fatigue life on dissolved oxygen (DO) and strain rate. The effect of strain rate on fatigue life saturates at some low value, e.g., between 0.0004 and 0.001%/s in oxygenated water with ∼0.8 ppm DO. The data suggest that the saturation value of strain rate may vary with DO and sulfur content of the steel. Although the cyclic stress-strain and cyclic-hardening behavior of carbon and low-alloy steels is distinctly different, the degradation of fatigue life of these two steels with comparable sulfur levels is similar. The carbon steel exhibits pronounced dynamic strain aging, whereas strain-aging effects are modest in the low-alloy steel. Environmental effects on nucleation of fatigue crack have also been investigated. The results suggest that the high-temperature oxygenated water has little or no effect on crack nucleation

  14. The study of quantitativeness in atom probe analysis of alloying elements in steel

    International Nuclear Information System (INIS)

    The quantitativeness in atom probe analysis of dilute solute alloying elements in steel was systematically investigated. The samples of binary Fe-Si, Fe-Ti, Fe-Cr, Fe-Cu, Fe-Mn and Fe-Mo alloys were prepared for present study. The apparent compositions of alloying elements were examined by three-dimensional atom probe (3DAP) under various experimental conditions. The temperature dependence of the apparent compositions varied largely with the alloys, which indicated that the degree of preferential evaporation or retention varied with the alloying elements. Furthermore, the analysis direction dependence of the apparent Mn composition was examined in the Fe-Mn alloy. The experimental results indicated that the order of the field evaporation rate of elements in steel was Cu>Cr>Mn∼Mo>Fe>Ti∼Si. The field evaporability of alloying elements in steel was discussed in terms of the solution enthalpy of the alloying elements and the phase types of the binary Fe alloys.

  15. Sintered stainless steel surface alloyed with Si3N4 powder

    OpenAIRE

    L.A. Dobrzański; Z. Brytan; W. Pakieła

    2011-01-01

    Purpose: The goal of this study was to investigate effects of laser surface alloying with Si3N4 powder on the microstructural changes and properties of vacuum sintered stainless steels, both austenitic X2CrNi17-12-2, ferritic X6Cr13 and duplex X2CrNiMo22-8-2.Design/methodology/approach: High power diode laser (HPDL) was applied to surface modification of sintered stainless steels with Si3N4 powder. The influence of laser alloying conditions on the width, penetration depth of alloyed surface l...

  16. Fatigue failure of micro-alloyed 23MnB4 steel

    Directory of Open Access Journals (Sweden)

    S. Rusz

    2008-12-01

    Full Text Available Purpose: In the following paper there have been the structure and fatigue properties of micro-alloyed 23MnB4 steel in initial state and after heat treatment evaluated.Design/methodology/approach: Fatigue test of micro-alloyed 23MnB4 steel was completed by metallographic and fracture analyses. For scope the methods of the light microscopy and SEM were used.Findings: Microstructure of examined alloy in initial state was characterized mostly by fine ferrite with pearlitic net and in state after heat treatment was formed by martensite or partly by bainite and after tempering was formed by tempered martensite. Objective of this work consisted in determination of fatigue characteristics of micro-alloyed 23MnB4 steel, including fracture analyze. Results of fatigue testing at various stress levels for the samples in initial state and after the heat treatment have confirmed that obtained values of cycles to rupture were at least 585 000 cycles. Change of fatigue properties in dependence on heat treatment of the used steel.Research limitations/implications: For define fracture area a samples must be provide with notch. The experiment was limited by occurrence a void in cast alloys.Practical implications: The results may be utilized for application of the investigated material in process of manufacturing.Originality/value: These results contribute to explanation of fracture mechanism of micro-alloyed 23MnB4 steel.

  17. Finite Element Simulation of Plastic Joining Processes of Steel and Aluminum Alloy Sheets

    International Nuclear Information System (INIS)

    Various high tensile strength steel sheets and an aluminum alloy sheet were joined with a self-piercing rivet. It is not easy to weld the aluminum alloy sheet and high tensile strength sheets by means of conventional resistance welding because of very different melting points. To obtain optimum joining conditions, joining defects were categorized into separation of the sheets and an inner fracture. The joining range of ultra high tensile strength steel and aluminum alloy sheets was extended by means of dies optimized by finite element simulation. The joint strength is greatly influenced by not only the strength of the sheets and rivets but also the ratio of the thickness of the lower sheet to the total thickness. In addition, mechanical clinching of high strength steel and aluminum alloy sheets was simulated

  18. TECHNOLOGICAL COMPLEX OF EQUIPMENT FOR REFINING AND CASTING OF STEEL AND ALLOYS IN THE FOUNDRY AND STEEL INDUSTRIES

    Directory of Open Access Journals (Sweden)

    V. I. Zolotukhin

    2015-05-01

    Full Text Available Vulcan TM is a small innovative company, specializing in the manufacture of steel and alloys casting systems and refractory accessories.Available for foundry and metallurgical industries, special technological equipment, designed and manufactured by LLC NPP “Vulkan-TM.”

  19. Parameters Optimization of Low Carbon Low Alloy Steel Annealing Process

    Institute of Scientific and Technical Information of China (English)

    Maoyu ZHAO; Qianwang CHEN

    2013-01-01

    A suitable match of annealing process parameters is critical for obtaining the fine microstructure of material.Low carbon low alloy steel (20CrMnTi) was heated for various durations near Ac temperature to obtain fine pearlite and ferrite grains.Annealing temperature and time were used as independent variables,and material property data were acquired by orthogonal experiment design under intercritical process followed by subcritical annealing process (IPSAP).The weights of plasticity (hardness,yield strength,section shrinkage and elongation) of annealed material were calculated by analytic hierarchy process,and then the process parameters were optimized by the grey theory system.The results observed by SEM images show that microstructure of optimization annealing material are consisted of smaller lamellar pearlites (ferrite-cementite)and refining ferrites which distribute uniformly.Morphologies on tension fracture surface of optimized annealing material indicate that the numbers of dimple fracture show more finer toughness obviously comparing with other annealing materials.Moreover,the yield strength value of optimization annealing material decreases apparently by tensile test.Thus,the new optimized strategy is accurate and feasible.

  20. Effect of Alloy 625 Buffer Layer on Hardfacing of Modified 9Cr-1Mo Steel Using Nickel Base Hardfacing Alloy

    Science.gov (United States)

    Chakraborty, Gopa; Das, C. R.; Albert, S. K.; Bhaduri, A. K.; Murugesan, S.; Dasgupta, Arup

    2016-04-01

    Dashpot piston, made up of modified 9Cr-1Mo steel, is a part of diverse safety rod used for safe shutdown of a nuclear reactor. This component was hardfaced using nickel base AWS ER NiCr-B alloy and extensive cracking was experienced during direct deposition of this alloy on dashpot piston. Cracking reduced considerably and the component was successfully hardfaced by application of Inconel 625 as buffer layer prior to hardface deposition. Hence, a separate study was undertaken to investigate the role of buffer layer in reducing the cracking and on the microstructure of the hardfaced deposit. Results indicate that in the direct deposition of hardfacing alloy on modified 9Cr-1Mo steel, both heat-affected zone (HAZ) formed and the deposit layer are hard making the thickness of the hard layer formed equal to combined thickness of both HAZ and deposit. This hard layer is unable to absorb thermal stresses resulting in the cracking of the deposit. By providing a buffer layer of Alloy 625 followed by a post-weld heat treatment, HAZ formed in the modified 9Cr-1Mo steel is effectively tempered, and HAZ formed during the subsequent deposition of the hardfacing alloy over the Alloy 625 buffer layer is almost completely confined to Alloy 625, which does not harden. This reduces the cracking susceptibility of the deposit. Further, unlike in the case of direct deposition on modified 9Cr-1Mo steel, dilution of the deposit by Ni-base buffer layer does not alter the hardness of the deposit and desired hardness on the deposit surface could be achieved even with lower thickness of the deposit. This gives an option for reducing the recommended thickness of the deposit, which can also reduce the risk of cracking.

  1. Study of austenitic stainless steel welded with low alloy steel filler metal. [tensile and impact strength tests

    Science.gov (United States)

    Burns, F. A.; Dyke, R. A., Jr.

    1979-01-01

    The tensile and impact strength properties of 316L stainless steel plate welded with low alloy steel filler metal were determined. Tests were conducted at room temperature and -100 F on standard test specimens machined from as-welded panels of various chemical compositions. No significant differences were found as the result of variations in percentage chemical composition on the impact and tensile test results. The weldments containing lower chromium and nickel as the result of dilution of parent metal from the use of the low alloy steel filler metal corroded more severely in a marine environment. The use of a protective finish, i.e., a nitrile-based paint containing aluminum powder, prevented the corrosive attack.

  2. Structure and properties of a layered steel/vanadium alloy/steel composite prepared by high-pressure torsion

    Science.gov (United States)

    Nikulin, S. A.; Rogachev, S. O.; Rozhnov, A. B.; Khatkevich, V. M.; Nechaikina, T. A.; Morozov, M. V.

    2016-04-01

    The microstructure and hardness of a layered steel 08Kh17T/V-10Ti-5Cr/steel 08Kh17T composite, which was prepared by torsion under a high hydrostatic pressure at temperatures of 20, 200, and 400°C, have been studied. Severe plastic deformation under used conditions is shown to provide good joining of layers, which is accompanied by their substantial hardening (from 2.0 to 3.5 times). During deformation at temperatures of 20 and 200°C, fragmentation of the vanadium alloy layer into thinner layers is observed; at 400°C, mainly a plane interface between the vanadium alloy and the steel layers is formed.

  3. Laser Alloyed Coatings of TiB2/Graphite on 9Cr18 Stainless Steel Surface

    Institute of Scientific and Technical Information of China (English)

    YING Li-xia; WANG Li-qin; JIA Xiao-mei; GU Le

    2007-01-01

    Modified coatings including carbide of iron, nickel, chromium, silicon, and titanium are obtained on 9Cr18 stainless steel surface by laser alloying. The processing method, the microstructure, the interface, the tribological properties, and the forming mechanisms of the coatings are analyzed. The results show that the microstructure of the alloyed coatings is mainly irregular FeC crystals. Carbides of chromium and iron are around the FeC crystals. Small granular TiC disperses in the alloyed coatings. The microhardness of the alloyed coatings is greatly improved because of the occurrence of carbide with high hardness. At the same time, the wear resistance of the alloyed coatings are higher than that of 9Cr18 stainless steel.

  4. Influence of kinetics of supercooled austenite decomposition on structure formation in sparingly-alloyed tool steel

    Science.gov (United States)

    Krylova, S. E.; Yakovleva, I. L.; Tereshchenko, N. A.; Priimak, E. Yu.; Kletsova, O. A.

    2013-10-01

    The decomposition of supercooled austenite in 70Kh3G2VTB steel under isothermal conditions and continuous cooling have been studied. The isothermal and continuous cooling tranformation curves of the decomposition of austenite in the experimental steel have been constructed. The effect of alloying elements on phase transformations in the steel under heating and cooling have been established. The features of the formation of a microstructure in the 70Kh3G2VTB steel after different regimes of heat treatment have been described. The optimal parameters of hardening heat treatment have been developed.

  5. High Carbon Alloy Steels with Multiple Types of Ultra-fine Carbides and Their Characteristics

    Institute of Scientific and Technical Information of China (English)

    MA Yong-qing; GAO Hong-tao; QI Yu-hong; ZHANG Zhan-ping; DAI Yu-mei; LIU Yan-xia

    2004-01-01

    Under normal forging and annealing conditions, there are different ultra fine carbides (M3C, M23C6, M7C3, M6C and MC) in high carbon alloy steels when alloy composition design is carried out properly. On the basis of carbides transformation orderliness, the alloy composition design of the high carbon alloy steels is conducted by phase-equilibrium thermodynamic calculation for Fe-Cr-W-Mo-V-C system. The nucleation and growth of new carbides, dissolution of previous partial carbides in these steels during annealing process, all these lead to ultra-fine distribution of carbides. Due to different crystal structures of carbides and different thermodynamics as well dynamics parameters of the carbides dissolution and precipitation, the range of quenching temperature of these steels is widened, and the good temper-resistance is obtained. The characteristics of heat treatment process and microstructure variance, and the carbides transformation for different temperature are explained by the phase-equilibrium component satisfactorily. Their bend and yield strength,flexibility and toughness all are advanced markedly comparing with that of kindred steels. Results of the applications have proved that the microstructure of ultra-fine carbides in these steels played importance roles in the enhancement of edginess and fatigue crack resistance of the die and knives.

  6. Modeling of Fe-Cr Martensitic Steels Corrosion in Liquid Lead Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Balbaud-Celerier, F.; Martinelli, L. [CEA Saclay, DEN, DPC, SCCME, Lab Etud Corros Non Aqueuse, F-91191 Gif Sur Yvette (France)

    2010-07-01

    Among the Generation IV systems, sodium fast reactors (SFRs) are promising and benefits of considerable technological experience. However, the availability and acceptability of the SFR are affected by the problems linked with the sodium-water reaction. One innovative solution to this problem is the replacement of the sodium in the secondary loops by an alternative liquid fluid. Among the fluids considered, lead-bismuth is at the moment being evaluated. Liquid lead-bismuth has been considerably studied in the frame of the research program on accelerator driven systems for transmutation applications. However, lead alloys are corrosive toward structural materials. The main parameters impacting the corrosion rate of Fe-Cr martensitic steels (considered as structural materials) are the nature of the steel (material side), temperature, liquid alloy velocity, and dissolved oxygen concentration (liquid alloy side). In this study, attention is focused on the behavior of Fe-9Cr steels, and more particularly, T91 martensitic steel. It has been shown that in the case of Fe-Cr martensitic steels, the corrosion process depends on the concentration of oxygen dissolved in Pb-Bi. For an oxygen concentration lower than the one necessary for magnetite formation (approximately {<=} 10{sup -8} wt % at T approximate to 500 degrees C for Fe-9Cr steels), corrosion proceeds by dissolution of the steel. For a higher oxygen content dissolved in Pb-Bi, corrosion proceeds by oxidation of the steel. These two corrosion processes have been experimentally and theoretically studied in CEA Saclay and also by other partners, leading to some corrosion modeling in order to predict the life duration of these materials as well as their limits of utilization. This study takes into account the two kinds of corrosion processes: dissolution and oxidation. In these two different processes, the lead alloy physico-chemical parameters are considered: the temperature and the liquid alloy velocity for both

  7. Effects of Nitrogen Content and Austenitization Temperature on Precipitation in Niobium Micro-alloyed Steels

    Institute of Scientific and Technical Information of China (English)

    Lei CAO; Zhong-min YANG; Ying CHEN; Hui-min WANG; Xiao-li ZHAO

    2015-01-01

    The influences of nitrogen content and austenitization temperature on Nb(C,N)precipitation in niobium micro-alloyed steels were studied by different methods:optical microscopy,tensile tests,scanning electron mi-croscopy,transmission electron microscopy,physicochemical phase analysis,and small-angle X-ray scattering. The results show that the strength of the steel with high nitrogen content is slightly higher than that of the steel with low nitrogen content.The increase in the nitrogen content does not result in the increase in the amount of Nb(C,N) precipitates,which mainly depends on the niobium content in the steel.The mass fraction of small-sized Nb(C,N) precipitates (1-10 nm)in the steel with high nitrogen content is less than that in the steel with low nitrogen con-tent.After austenitized at 1 150 ℃,a number of large cuboidal and needle-shaped particles are detected in the steel with high nitrogen content,whereas they dissolve after austenitized at 1 200 ℃ and the Nb(C,N)precipitates become finer in both steels.Furthermore,the results also show that part of the nitrogen in steel involves the formation of al-loyed cementite.

  8. Laser surface alloying of sintered stainless steels with SiC powder

    Directory of Open Access Journals (Sweden)

    Z. Brytan

    2011-07-01

    Full Text Available Purpose: The goal of this study is to investigate effects of laser surface alloying with SiC powder on microstructural changes and properties of vacuum sintered austenitic X2CrNiMo17-12-2, ferritic X6Cr13 and duplex X2CrNiMo22-8-2 stainless steels.Design/methodology/approach: Surface modification of sintered stainless steels was carried out by laser surface alloying with SiC powder using high power diode laser (HPDL. The influence of laser alloying conditions, the laser beam power (between 0.7 and 2.1 kW at constant scanning rate on the width of alloyed surface layer and penetration depth were studied. The resulting microstructure in laser alloyed surface layer was examined using light and scanning electron microscopy. Phase composition was determined by the X-ray diffraction method. The microhardness results of modified surface layer were also studied.Findings: The alloyed surface layer has a fine dendritic microstructure with iron-chromium carbides precipitations. The surface layer was enriched in silicon and carbon that produced microstructural changes and resulting microhardness increase. Beside studied stainless steels the duplex one revealed highest hardening effect by laser alloying with SiC powder, where related microhardness was about 500-600 HV.Practical implications: Laser surface alloying with SiC powder can be an efficient method of surface layer hardening of sintered stainless steels and produce significant improvement of surface layer properties in terms of hardness and wear resistance.Originality/value: Application of high power diode laser can guarantee uniform heating of treated surface, thus uniform thermal cycle across processed area and uniform penetration depth of alloyed surface layer.

  9. Alloy element redistribution during sintering of powder metallurgy steels

    OpenAIRE

    Tahir, Abdul Malik

    2014-01-01

    Homogenization of alloying elements is desired during sintering of powder metallurgy components. The redistribution processes such as penetration of liquid phase into the interparticle/grain boundaries of solid particles and subsequent solid-state  diffusion of alloy element(s) in the base powder, are important for the effective homogenization of alloy element(s) during liquid phase sintering of the mixed powders. The aim of this study is to increase the understanding of alloy element redistr...

  10. 77 FR 21968 - Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's Republic of...

    Science.gov (United States)

    2012-04-12

    ... International Trade Administration Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the... countervailing duty order on seamless carbon and alloy steel standard, line, and pressure pipe from the People's... Antidumping and Countervailing Duty Administrative Reviews and Request for Revocation in Part, 76 FR...

  11. 75 FR 29972 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe from the People's...

    Science.gov (United States)

    2010-05-28

    ... Determination, 75 FR 22372 (April 28, 2010) (``Preliminary Determination''). On May 3, 2010, Tianjin Pipe (Group... International Trade Administration Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe... antidumping duty investigation of certain seamless carbon and alloy steel standard, line, and pressure...

  12. 75 FR 6183 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe from the People's...

    Science.gov (United States)

    2010-02-08

    ... investigation on certain seamless carbon and alloy steel standard, line, and pressure pipe from the People's Republic of China. See Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's Republic of China: Initiation of Antidumping Duty Investigation, 74 FR 52744 (October 14,...

  13. 75 FR 57449 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe from the People's...

    Science.gov (United States)

    2010-09-21

    ... International Trade Administration Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe... determined that certain seamless carbon and alloy steel standard, line, and pressure pipe from the People's..., in Part, and Postponement of Final Determination, 75 FR 22372 (April 28, 2010)...

  14. 78 FR 34342 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Final Results and Partial Rescission of...

    Science.gov (United States)

    2013-06-07

    ... Fair Value: Certain Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453 (November 2, 1992) (Antidumping... Circular Welded Non-Alloy Steel Pipe from Mexico, 75 FR 82374 (December 30, 2010). Mueller submitted a ``no... Rescission of Antidumping Duty Administrative Review; 2010-11, 77 FR 73617 (December 11, 2012)...

  15. 75 FR 34980 - Circular Welded Non-Alloy Steel Pipe from the Republic of Korea: Final Results of the Antidumping...

    Science.gov (United States)

    2010-06-21

    ... Welded Non-Alloy Steel Pipe and Tube From Brazil, the Republic of Korea, Mexico, and Venezuela, 61 FR... Sales at Less Than Fair Value: Certain Circular Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453... Korea: Preliminary Results and Rescission in Part of the Antidumping Duty Administrative Review, 74...

  16. 76 FR 36089 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Final Results of the Antidumping...

    Science.gov (United States)

    2011-06-21

    ... Welded Non-Alloy Steel Pipe and Tube From Brazil, the Republic of Korea, Mexico, and Venezuela, 61 FR... Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453 (November 2, 1992). These deposit requirements shall... Republic of Korea: Preliminary Results of the Antidumping Duty Administrative ] Review, 75 FR...

  17. 46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

    Science.gov (United States)

    2010-10-01

    ... (incorporated by reference; see 46 CFR 54.01-1) for service temperatures below −425 °F., UHA-51(b)(1) through (5... 46 Shipping 2 2010-10-01 2010-10-01 false Low temperature operation-high alloy steels (modifies....25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a)...

  18. 75 FR 39917 - Circular Welded Non-Alloy Steel Pipe from the Republic of Korea: Extension of Time Limit for...

    Science.gov (United States)

    2010-07-13

    ... for Revocation in Part, 74 FR 68229 (December 23, 2009). The current deadline for the preliminary... International Trade Administration (A-580-809) Circular Welded Non-Alloy Steel Pipe from the Republic of Korea... non-alloy steel pipe from the Republic of Korea, covering the period November 1, 2008 through...

  19. 78 FR 60850 - Carbon and Certain Alloy Steel Wire Rod From Brazil: Final Results of the Expedited Second Sunset...

    Science.gov (United States)

    2013-10-02

    ... Alloy Steel Wire Rod from Brazil, 67 FR 55805 (August 30, 2002). \\2\\ See Initiation of Five-Year (``Sunset'') Review, 78 FR 33063 (June 3, 2013). On June 18, 2013, the Department received a notice of... International Trade Administration Carbon and Certain Alloy Steel Wire Rod From Brazil: Final Results of...

  20. 78 FR 63450 - Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and...

    Science.gov (United States)

    2013-10-24

    ... Act. See Initiation of Five-Year (``Sunset'') Reviews, 78 FR 33063 (June 3, 2013) (``Notice of... International Trade Administration, Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico... on carbon and certain alloy steel wire rod (``wire rod'') from Brazil, Indonesia, Mexico,...

  1. 78 FR 60316 - Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and...

    Science.gov (United States)

    2013-10-01

    ... both that the domestic interested party group response to its notice of institution (78 FR 33103, June... Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and Tobago, and Ukraine... determine whether revocation of the countervailing duty order on carbon and certain alloy steel wire...

  2. 77 FR 8808 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Extension of the Final Results...

    Science.gov (United States)

    2012-02-15

    ... From the Republic of Korea: Preliminary Results of the Antidumping Duty Administrative Review, 76 FR... International Trade Administration Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Extension of... antidumping duty administrative review of circular welded non-alloy steel pipe from the Republic of...

  3. Some aspects of the alloying theory of steels for turbine rotors and generators

    International Nuclear Information System (INIS)

    The alloying element effects on mechanical properties of Cr-Ni-Mo-V steels used for manufacture of main components of power plants are investigated. With the aim of selection of proper alloying a generalized diagram is built which relates the process of carbide formation and the content of chromium in a matrix to mean concentrations of alloying elements in the steel as well as to the duration of temper. New steels for manufacture of turbine rotors and generators are proposed (32KhM1A, 25Kh2MFA, 25Kh2MFAA, 20KhN2MFASh, 25Kh2N2MFAA, 20KhN3MA, 36KhN3MFAA, 15KhN4MFAA)

  4. Corrosion resistance of stainless steels and high Ni-Cr alloys to acid fluoride wastes

    International Nuclear Information System (INIS)

    TRUEX processing of Hanford Site waste will utilize potentially corrosive acid fluoride processing solutions. Appropriate construction materials for such a processing facility need to be identified. Toward this objective, candidate stainless steels and high Ni-Cr alloys have been corrosion tested in simulated acid fluoride process solutions at 333K. The high Ni-Cr alloys exhibited corrosion rates as low as 0.14 mm/y in a solution with an HF activity of about 1.2 M, much lower than the 19 to 94 mm/y observed for austenitic stainless steels. At a lower HF activity (about 0.008 M), stainless steels display delayed passivation while high Ni-Cr alloys display essentially no reaction

  5. An Automated System To Classify Alloy Steel Surface Using Contourlet Transform

    Directory of Open Access Journals (Sweden)

    Mr.N.Vimalraj

    2014-01-01

    Full Text Available Surface defect detection of metallic surfaces is a major challenge in any manufacturing industry. In this paper, an automated system to classify alloy steel surface based on contourlet transform is presented. As the contourlet transform is a multi resolution analysis, texture present in alloy steel surface is represented in various scales and directions. The image is decomposed at various scales and directions and the energy features are extracted. By analyzing the energies from the trained images, the best set that distinguishes the surface into defect or non defect is chosen for classification. The classification results are evaluated on the given set of images of alloy steel surface and the performance of the system is evaluated.

  6. Bonding evolution with sintering temperature in low alloyed steels with chromium

    Directory of Open Access Journals (Sweden)

    Fuentes-Pacheco L.

    2009-01-01

    Full Text Available At present, high performance PM steels for automotive applications follow a processing route that comprises die compaction of water-atomized powder, followed by sintering and secondary treatments, and finishing operations. This study examines Cr-alloyed sintered steels with two level of alloying. In chromium-alloyed steels, the surface oxide on the powder is of critical importance for developing the bonding between the particles during sintering. Reduction of this oxide depends mainly on three factors: temperature, dew point of the atmosphere, and carbothermic reduction provided by the added graphite. The transformation of the initial surface oxide evolves sequence as temperature increases during sintering, depending on the oxide composition. Carbothermic reduction is supposed to be the controlling mechanism, even when sintering in hydrogen-containing atmospheres. The effect of carbothermic reduction can be monitored by investigating the behavior of the specimens under tensile testing, and studying the resultant fracture surfaces.

  7. Characterization of Rust Layer Formed on Low Alloy Steel Exposed in Marine Atmosphere

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The iron rust phases formed on Iow alloy steels containing different quantities of Cr element have been characterizedusing EPMA, Raman spectroscopy, TEM, optical microscopy etc. The ion selective properties of synthesized rust filmswith the same phase constituent as the atmospheric corrosion products were investigated using self-made apparatus.The results showed that corrosion loss of steels exposed in marine atmosphere decreased rapidly as the Cr contentof the steel was increased. Cr-containing steels were covered by a uniform compacted rust layer composed of fineparticles with an average diameter of several nanometers. Inner rust layer of Cr-containing steel (2 mass fraction)was composed of α-CrxFel-xOOH, with Cr content of about 5 mass fraction. Such rust layer showed cation selectiveproperty, and could depress the penetration of Cl- to contact substrate steel directly.

  8. The effect of Fe-Mn-Al-C steel alloying with high-melting metal

    International Nuclear Information System (INIS)

    A study is made into the influence of strong carbide-forming elements (V and Nb), in amounts exceeding their solubility in a solid solution, on structure and properties of steels with a basic composition of Fe-29%Mn-9%Al-0.9%C. It is shown that the alloying with V and Nb which form thermally stable carbides promote an essential grain refinement. It is noted that it is advantageous to alloy manganese steels with more weak carbide-forming elements (W, Mo) within the limit of their solubility in a solid solution considering that carbon thermodynamic activity is suppressed, diffusion processes are retarded and the temperature of steel operation increases up to 500 deg C. Mechanical properties of various composition steels depending on heat treatment conditions are given

  9. Effect of thermal cycling on the alloy 800/2.25 Cr-1 Mo steel joint

    International Nuclear Information System (INIS)

    The critical part of the trimetallic transition joint (type 304 stainless steel/Alloy 800/2.25 Cr-1 Mo steel), the Alloy 800/2.25 Cr-1 Mo steel joint welded with Inconel 182, was subjected to thermal cycling between room temperature and 873 K. The thermal cycling test procedure used produces accelerated failures in transition joints similar to those observed in steam generators of operating power plants. On thermal cycling, precipitation at the weld/ferritic steel interface decreased on post-weld heat treatment. This precipitation increased with increased prior ageing and applied stress. The results of these tests indicated a considerable improvement in performance of the trimetallic transition joint compared to the direct (bimetallic) transition joint. (orig.)

  10. Fine structures in Fe3Al alloy layer of a new hot dip aluminized steel

    Indian Academy of Sciences (India)

    Li Yajiang; Wang Juan; Zhang Yonglan; X Holly

    2002-12-01

    The fine structure in the Fe–Al alloy layer of a new hot dip aluminized steel (HDA) was examined by means of X-ray diffractometry (XRD), electron diffraction technique, etc. The test results indicated that the Fe–Al alloy layer of the new aluminized steel mainly composed of Fe3Al, FeAl and -Fe (Al) solid solution. There was no brittle phase containing higher aluminum content, such as FeAl3 (59.18% Al) and Fe2Al7 (62.93% Al). The tiny cracks and embrittlement, formerly caused by these brittle phases in the conventional aluminum-coated steel, were effectively eliminated. There was no microscopic defect (such as tiny cracks, pores or loose layer) in the coating. This is favourable to resist high temperature oxidation and corrosion of the aluminized steel.

  11. Microstructure and corrosion behavior of shielded metal arc-welded dissimilar joints comprising duplex stainless steel and low alloy steel

    Science.gov (United States)

    Srinivasan, P. Bala; Muthupandi, V.; Sivan, V.; Srinivasan, P. Bala; Dietzel, W.

    2006-12-01

    This work describes the results of an investigation on a dissimilar weld joint comprising a boiler-grade low alloy steel and duplex stainless steel (DSS). Welds produced by shielded metal arc-welding with two different electrodes (an austenitic and a duplex grade) were examined for their microstructural features and properties. The welds were found to have overmatching mechanical properties. Although the general corrosion resistance of the weld metals was good, their pitting resistance was found to be inferior when compared with the DSS base material.

  12. Application of LIBS technique to interdiffusion between Zr-based alloys and martensitic stainless steels

    International Nuclear Information System (INIS)

    The following paper presents a breakthrough in the study of interdiffusion between a Zr2,5wt% Nb alloy and martensitic steel grade ASTM 410, which are important materials in the nuclear industry, in this case through the Laser Induced Breakdown Spectroscopy (LIBS) technique. The interdiffusion profiles obtained showed qualitatively a slow diffusion of zirconium and niobium in the steel matrix as well as a fast diffusion of Fe, C, Cr and Ni, in the matrix of the zirconium alloy. Besides the presence of intermetallic phases can also be detected through this technique, in agreement to optical and scanning electronic microscopy analysis

  13. Structure and properties of laser alloyed gradient surface layers of the hot-work tool steels

    OpenAIRE

    L.A. Dobrzański; M. Bonek; E. Hajduczek; K. Labisz; M. Piec; E. Jonda; A. Polok

    2008-01-01

    Purpose: The purpose of this research paper is focused on the 55NiCrMoV7, 32CrMoV12-28, X40CrMoV5-1, X38CrMoV5-3 hot work tool steels surface layers improvement properties using HPDL laser. The paper present laser surface technologies, investigation of structure and properties of the hot work tool steels alloying with ceramic particles using high power diode laser HPDL.Design/methodology/approach: Investigation indicate the influence of the alloying carbides on the structure and properties of...

  14. The mechanism of the surface alloy layer creation for cast steel

    Directory of Open Access Journals (Sweden)

    A. Walasek

    2012-01-01

    Full Text Available The paper presents a detailed description of the process of creation of a surface alloy layer (using high-carbon ferrochromium on the cast steel casting. The mechanism of the surface alloy layer is based on the known theories [5,6]. The proposed course of formation of the layers has been extended to decarburization stage of steel. The research included proving the presence of carbon-lean zone. The experiment included the analysis of the distribution of elements and microhardness measurement.

  15. Tribological Properties of WS2 Nanoparticles Lubricants on Aluminum-Silicon Alloy and Carbon Steels

    OpenAIRE

    Riyadh A. AL-SAMARAI; Yarub AL-DOURI; Haftirman HAFTIRMAN; Khiarel Rafzi AHMAD

    2013-01-01

    The rheological properties of nanometric tungsten disulphide (WS2) nanoparticles oil lubricants and its tribological performance with two hypereutectic Al-Si alloy and carbon steel are examined. These two oils are used to reduce wear and friction and to explore the actions via tribological pin-on-disk tests. The pin was made from hypereutectic Al-Si alloy on steel disk, taking into consideration the effect of loads (10, 20, 30 N) and different speed (200, 300, 400 rpm). Oils with and without ...

  16. Laser welding of AZ31B magnesium alloy to Zn-coated steel

    International Nuclear Information System (INIS)

    Highlights: ► Magnesium alloy was successfully laser welded to Zn-coated steel. ► The joint strength exceeded 6000 N on a 25 mm wide specimen. ► A 450 nm thick layer of Fe3Al was uniformly formed on the steel surface. -- Abstract: The characteristics of laser lap welding of AZ31B magnesium alloy to Zn-coated steel were investigated. Welding was difficult when the laser beam was irradiated onto the AZ31B alloy and the processing parameters were set to obtain a keyhole welding mode. The difference in the physical properties between the two materials resulted in unstable welding process particularly when the laser beam penetrated into the steel specimen and a keyhole was formed therein. By switching to a conduction mode, the process stability was improved and successful welding could be achieved because the liquid metal film remained unbroken and the laser beam did not penetrate into the material. A 25 mm wide joint failed in tensile shear testing at loads exceeding 6000 N. This high joint strength was attributed to the formation of a 450 nm thick layer of Fe3Al intermetallic compound on the steel surface as a result of the interaction between Al from the AZ31B alloy and Fe. The presence of Zn-coating layer was essential to eliminate the negative effects of oxides on the joining process.

  17. Characterization of steel 1035 hot-dip-aluminized in pure Al and Al-Cu alloys

    International Nuclear Information System (INIS)

    Medium carbon steel strips containing 0.35% carbon were hot-dip-aluminized in pure AI and AI-Cu alloys. An iron-aluminum interlayer, which is brittle in nature, developed at the interface between the melt and the steel substrate. Cu additions (4-16% by weight) in AI affected the growth rate of interlayer as well as the hardness and oxidation resistance of the aluminized surface. These effects were examined by using scanning electron microscopy, XRD 'X-Ray Diffraction'), and TGA (Thermal Gravimetric Analysis). In HAD (Hot Dip Aluminizing) with pure aluminum, the interlayer was 'thick' and exhibited a finger-like growth into steel substrate. While aluminizing in AI-Cu alloys, the thickness of the interlayer decreased consistently by gradually increasing the addition of Cu content in AI from 4-16%. Further, the addition of Cu beyond 12% transformed finger-like interface into nearly smooth interface. XRD analysis revealed that due to Cu addition, the tetragonal phases, Al/sub 2/ Cu and AI7Cu/sub 2/ Fe formed in surface coating in addition to FeAI/sub 3/ and Fe/sub 2/ Al/sub 5/ which generally form in steel HDA in pure Al. Their formation caused to reduce the growth of interlayer. Steel surface aluminized in AI-Cu alloys exhibited better hardness than of aluminized in pure AI and AI-Si alloys and also expressed excellent oxidation resistance up to 632 degree C. (author)

  18. Surface hardening of steels by alloying under laser heating with subsequent chemical thermal treatment

    International Nuclear Information System (INIS)

    The combination of laser alloying of carbon and low-chromium steels (20, 40, 45, 20Kh and 40Kh) with nitride-forming elements (V, Cr, Mo, Al) and subsequent nitriding is under consideration as a promising technology of enhancing wear resistance of steels. It is shown that the technology proposed permits increasing microhardness, wear resistance and favourable distribution of residual stresses in surface layers

  19. Cold worked high alloy ultra-high strength steels with aged martensite structure

    Directory of Open Access Journals (Sweden)

    H.J. Krztoń

    2009-09-01

    Full Text Available Purpose: The study on structure-property relations of heavily cold worked and aged martensite in two high-alloy structural steels was presented. The aim was to understand properties of the sheet products better and thus extend applications of the newly developed cobalt-free maraging and precipitation hardening stainless steels.Design/methodology/approach: Mechanical tests were performed on cold rolled and aged specimens. Microstructures were analyzed using TEM and SEM. The crystallographic texture was analyzed by means of X-ray diffraction and ADC method.Findings: In the process of cold working and ageing both high alloy steels studied could develop yield strength in excess of 1600 MPa. The main strengthening mechanism was precipitation hardening, while work hardening contribution to the strength was very limited. Overaging commences after prolonged treatment above 500ºC, and in both steels could be related to reverted austenite. The texture developed by cold working was the one known as rolling texture type.Research limitations/implications: In this study the advantage is taken of the high strength that is developed by cold working followed by ageing. Further research is needed for the sheet or strip produced by cold working and annealed before fabrication.Practical implications: The properties of the high alloy steels studied make them suitable for advanced sheet applications, e.g. as an airborne structural equipment. After welding, strength of the precipitation hardening steels could be largely restored by ageing, because their strength does not rely on strain hardening.Originality/value: Analysis of the cold worked properties, microstructure and texture, allowed for better understanding of the microstructure-property relationships in the low strain hardening high alloy sheet steels. The results obtained are of practical value for the development, production and manufacture of the ultra-high strength sheet steels.

  20. The Effect of Microstructure on the Abrasion Resistance of Low Alloyed Steels

    OpenAIRE

    Xu, X.

    2016-01-01

    The thesis attempts to develop advanced high abrasion resistant steels with low hardness in combination with good toughness, processability and low alloying additions. For this purpose, a novel multi-pass dual-indenter (MPDI) scratch test approach has been developed to approach the real continuous abrasion process and unravel abrasion damage formation in construction steels, i.e. carrying out scratch tests using a large indenter with different pre-loads to generate a wide pre-scratch with sta...

  1. The welding of austenitic-ferritic Mo-alloyed Cr-Ni-Steel

    International Nuclear Information System (INIS)

    This paper provides general information and guidance on the welding of austenitic-ferritic Mo-alloyed Cr-Ni stainless steel. Information is given on the various chemical compositions and on resistance to corrosion and on the mechanical and physical properties of commercially available steels. The effect of welding on the base metal and the selection of welding processes and welding consumables are described

  2. Effects of strain and trapping on hydrogen-induced cracking in high strength low alloy steels

    OpenAIRE

    Bosch, Cédric; Delafosse, David; Longaygue, Xavier

    2010-01-01

    International audience In pearlitic steels, hydrogen trapping at interphase boundaries may induce hydrogen- cracking in the absence of external applied stress such as in blistering and Hydrogen Induced Cracking. However, in low alloy steels containing a much lower density of such trapping sites and/or when hydrogen activity is reduced, most instances of hydrogen-induced cracking involve strong interactions between local plasticity and hydrogen effects. We investigated the effects of these ...

  3. Stress corrosion cracking and hydrogen embrittlement of thick section high strength low alloy steel.

    OpenAIRE

    Needham, William Donald

    1986-01-01

    An experimental study was conducted to evaluate the corrosion performance of weldments of a high strength low alloy(HSLA) steel in a simulated seawater environment. This steel, designated HSLA80, was developed by the United States Navy for use in ship structural applications. Stress corrosion CRACKING(SCC) and hydrogen embrittlement(HEM) were investigated by conducting 42 Wedge-Opening load(WOL) tests as a function of stress intensity and corrosion potential and 33 Slow Strain Rate(SSR) tests...

  4. Cold weld cracking susceptibility of high strength low alloyed (HSLA) steel NIONIKRAL 70

    OpenAIRE

    Tawengi, A. S.; A. Sedmak; Grabulov, V.

    2014-01-01

    In view of the importance of high strength low alloy (HSLA) steels, particularly for critical applications such as offshore plat forms, pipeline and pressure vessels, this paper reports on an investigation of how to weld this type of steel without cold cracking. Using manual metal arc welding process and Tekken test (Y - Grove test) has been carried out both to observe the cold cracking phenome non, and to investigate the influencing factors, such as preheating temperature and energy input, a...

  5. Optimization and Statistical Analysis of Machining Parameters for Tool Wear Rate on EN-19 Alloy Steel

    OpenAIRE

    Manish Vishwakarma; Vishal Parashar; V.K.Khare

    2012-01-01

    In this paper, an attempt has been made to machine the EN-19 alloy steel by using rectangular shaped copper electrode perform on electrical discharge machine. This work attempts to investigate the effects of input current, pulse on time, duty cycle, voltage gap and flushing pressure on electrode wear rate (EWR) of EN-19 alloy steelin EDM using copper electrode. A regression model for the electrode wear rate has been developed to develop relation between input and responses. Design of experime...

  6. The effect of dissolved stainless steel alloy elements on the activity and growth of SRB

    OpenAIRE

    F. A. Lopes; Morin, P.; Oliveira, Rosário; Melo, L. F.

    2000-01-01

    Sulphate reducing bacteria have an important role in the sulphur cycle, and therefore in wastewater treatment systems. They are able to form biofilms on metallic surfaces, leading to fouling and corrosion problems. These bacteria are among the micro-organisms most frequently implicated in microbial corrosion of iron and ferrous alloys. Alloying elements added to steels for the improvement of their corrosion resistance such as molybdenum and nickel can be dissolved in bulk liqui...

  7. LASER SURFACE ALLOYING OF A MILD STEEL FOR CORROSION RESISTANCE IMPROVEMENT

    OpenAIRE

    Fouquet, F.; Renaud, L.; Millet, J.; Mazille, H.

    1991-01-01

    Surface alloys were produced by laser melting of different predeposits into the outer part of a mild steel substrate. Three types of coatings were used : electroless nickel (containing phosphorous), electroless nickel in which chromium carbide particles were introduced during deposition and duplex coatings made of, first, a nickel layer (electroless or electrodeposited) and then, a chromium layer. The surface alloying treatments were performed using a cw high power CO2 laser and the multiple ...

  8. Surface Chemistry of Aluminium Alloy Slid against Steel Lubricated by Organic Friction Modifier in Hydrocarbon Oil

    OpenAIRE

    Ichiro Minami; Ayumi Sugibuchi

    2012-01-01

    The lubrication mechanism of aluminium alloy slid against steel was investigated from the standpoint of surface chemistry. Low friction and low wear were observed using glycerol mono-olate in a hydrocarbon as lubricant. Increase in the silicon content in the aluminium alloy during rubbing was observed by surface analyses using (1) Auger electron spectroscopy, (2) scanning electron microscopy along with energy dispersive X-ray spectroscopy, and (3) X-ray photoelectron spectroscopy. Mild remova...

  9. Comparative MRI compatibility of 316 L stainless steel alloy and nickel-titanium alloy stents.

    Science.gov (United States)

    Holton, Andrea; Walsh, Edward; Anayiotos, Andreas; Pohost, Gerald; Venugopalan, Ramakrishna

    2002-01-01

    The initial success of coronary stenting is leading to a proliferation in peripheral stenting. A significant portion of the stents used in a clinical setting are made of 316 low carbon stainless steel (SS). Other alloys that have been used for stent manufacture include tantalum, MP35N, and nickel-titanium (NiTi). The ferromagnetic properties of SS cause the production of artifacts in magnetic resonance imaging (MRI). The NiTi alloys, in addition to being known for their shape memory or superelastic properties, have been shown to exhibit reduced interference in MRI. Thus, the objective of this study was to determine the comparative MRI compatibility of SS and NiTi stents. Both gradient echo and spin-echo images were obtained at 1.5 and 4.1 T field strengths. The imaging of stents of identical geometry but differing compositions permitted the quantification of artifacts produced due to device composition by normalizing the radio frequency shielding effects. These images were analyzed for magnitude and spatial extent of signal loss within the lumen and outside the stent. B1 mapping was used to quantify the attenuation throughout the image. The SS stent caused significant signal loss and did not allow for visibility of the lumen. However, the NiTi stent caused only minor artifacting and even allowed for visualization of the signal from within the lumen. In addition, adjustments to the flip angle of standard imaging protocols were shown to improve the quality of signal from within the lumen. PMID:12549230

  10. Corrosion inhibition by naturally occurring Hibiscus sabdariffa plant extract on a mild steel alloy in HCl solution

    OpenAIRE

    AMEER, MAGDA ABDO MAHMOUD; FEKRY, AMANY MOHAMED

    2015-01-01

    The corrosion inhibition of mild steel alloys is of tremendous technological importance due to their increased industrial applications. Potentiodynamic polarization and electrochemical impedance spectroscopy techniques were used to establish the effect of different concentrations of HCl on the corrosion behavior of mild steel. A study was conducted on the inhibition of dissolution for a mild steel alloy in the most corrosive concentration of HCl (5 M) by adding different concentrations of aqu...

  11. Electronic Structures and Alloying Behaviors of Ferrite Phases in High Co-Ni Secondary Hardened Martensitic Steels

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The electronic structure of ferrite (tempered martensite phase) in high Co-Ni secondary hardened martensitic steel has been investigated. The local density of states (LDOS) of alloying elements in the steel displays the relationship between solid solubility and the shape of the LDOS. The bond order integral (BOI) between atoms in the steel shows that the directional bonding of the p orbital of Si or C leads to the brittleness of the steel. At last, ∑BOI between atoms demonstrate that C, Co, Mn, Cr, Mo, Si strengthen the alloyed steel through solid-solution effects.

  12. The development of Ti-alloyed high strength microalloy steel

    International Nuclear Information System (INIS)

    Microalloy steels are generally Nb, V, or Nb, V, Ti composite microalloyed. Because of the high price of niobium and vanadium, the development of titanium microalloyed steels is a very interesting subject. In this study, steels with different Ti contents were refined and forged. Tensile tests were conducted and microstructures of samples were analyzed. Fine precipitates were observed using a transmission electron microscope. The results show that nanoscale Ti precipitates is the main factor enhancing strength of steels. The strength of steels increases with the Ti content. The optimum content range of titanium is between 0.04 and 0.10 wt.% while below 0.04 wt.% and higher than 0.10 wt.%, Ti has little effect on the strength of steels.

  13. 78 FR 33809 - Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's Republic of...

    Science.gov (United States)

    2013-06-05

    ...In response to a request from an interested party, United States Steel Corporation (``U.S. Steel''), the Department of Commerce (``the Department'') initiated an administrative review of the antidumping duty order on seamless carbon and alloy steel standard, line, and pressure pipe from the People's Republic of China. The period of review is November 1, 2011, through October 31, 2012. Based on......

  14. Parallel between steels alloyed with chrome-nickel and Fe-Mn-Al-C steels, in their response to fracture and wear (Review)

    International Nuclear Information System (INIS)

    The big worldwide demand for chrome-nickel alloy steels ('conventional steel') leads to the need for advanced materials for applications in different engineering systems that operate at high temperatures and in aggressive environmental conditions, favoring research and development in alternate alloys. In this technological race in search of these new materials, the FeMnAlC alloys ('new steels') have attracted attention for their excellent mechanical and tribological properties as well as for their good performance in corrosive-oxide environments, which make them similar to conventional steel. There are two important similarities between these two steels. First, an agent that causes the passive film to become stainless appears in both steels: chrome in the conventional steel, and aluminum in the FeMnAl alloy. The second similarity is that a stabilizing agent of the austenitic phase (FCC) appears in both, so that excellent mechanical properties can be obtained: nickel in the conventional steel, and manganese in the FeMnAl alloy. In certain sectors, such as aeronautics, conventional steel is rarely used because it is a very heavy material. This conventional steel is almost three times heavier that aluminum (7.85/2.7). Two advantages that the new FeMnAIC steels have compared to the conventional steels are that they are about 13% lighter in weight and they are less expensive. The FeMnAl also have excellent mechanical properties and good corrosion-oxidation resistance, which generates big expectations for their application in a broad scientific spectrum. This work reports the state of the information currently available about FeMnAlC alloys, comparing the mechanical and tribological behaviors of conventional alloy steels with chrome and nickel alloys, specifying the scopes of their application. A condition that favors the steels' fragility is the high speed of deformation and impact, where the FCC crystalline structure materials do not have a fragile ductile transition

  15. Development of microstructure in high-alloy steel K390 using semi-solid forming

    Science.gov (United States)

    Opatova, K.; Aisman, D.; Rubesova, K.; Ibrahim, K.; Jenicek, S.

    2016-03-01

    Semi-solid processing of light alloys, namely aluminium and magnesium alloys, is a widely known and well-established process. By contrast, processing of powder steels which have high levels of alloying elements is a rather new subject of research. Thixoforming of high-alloy steels entails a number of technical difficulties. If these are overcome, the method can offer a variety of benefits. First of all, the final product shape and the desired mechanical properties can be obtained using a single forming operation. Semi-solid forming can produce unusual powder steel microstructures unattainable by any other route. Generally, the microstructures, which are normally found in thixoformed steels, consist of large fractions of globular or polygonal particles of metastable austenite embedded in a carbide network. An example is the X210Cr12 steel which is often used for semi-solid processing experiments. A disadvantage of the normal microstructure configuration is the brittleness of the carbide network, in which cracks initiate and propagate, causing low energy fractures. However, there is a newly-developed mini-thixoforming route which produces microstructures with an inverted configuration. Here, the material chosen for this purpose was K390 steel, in which the content of alloying elements is up to 24%. Its microstructure which was obtained by mini- thixoforming did not contain polyhedral austenite grains but hard carbides embedded in a ductile austenitic matrix. This provided the material with improved toughness. The spaces between the austenite grains were filled with a eutectic in which chromium, molybdenum and cobalt were distributed uniformly. After the processing parameters were optimized, complexshaped demonstration products were manufactured by this route. These products showed an extraordinary compressive strength and high wear resistance, thanks to the hardness of their microstructure constituents, predominantly the carbides.

  16. Effects of LWR environments on fatigue life of carbon and low-alloy steels

    International Nuclear Information System (INIS)

    SME Boiler and Pressure Vessel Code provides construction of nuclear power plant components. Figure I-90 Appendix I to Section III of the Code specifies fatigue design curves for structural materials. While effects of environments are not explicitly addressed by the design curves, test data suggest that the Code fatigue curves may not always be adequate in coolant environments. This paper reports the results of recent fatigue tests that examine the effects of steel type, strain rate, dissolved oxygen level, strain range, loading waveform, and surface morphology on the fatigue life of A 106-Gr B carbon steel and A533-Gr B low-alloy steel in water

  17. Tensile and impact behaviour of sinter-forged Cr, Ni and Mo alloyed powder metallurgy steels

    International Nuclear Information System (INIS)

    Sintered and forged low-alloy P/M steels containing Cr, Ni and Mo were subjected to tensile, hardness and impact tests, in order to understand the influence of the alloying elements and microstructure on their mechanical properties. Elemental powders of atomized iron, graphite, chromium, nickel and molybdenum were mixed in suitable proportions using a ball mill, compacted and sintered in order to yield the following alloy compositions: Fe-0.2%C, Fe-0.2%C-1%Cr, Fe-0.2%C-1%Cr-2%Ni, Fe-0.2%C-2%Ni and Fe-0.2%C-2%Ni-1.5%Mo. Cylindrical compacts of 24 mm diameter and 32 mm height were prepared from the powder mixes in a 1000 kN hydraulic press using suitable cylindrical die-punch combination. Sintering of the ceramic-coated cylindrical preforms was carried out at 1000 ± 10 oC in a muffle furnace for a period of 120 min. Immediately after sintering, the cylindrical compacts were hot upset forged and drawn into square cross-section bars of density values to near-theoretical using a 2000 kN friction screw press. The size of the bars was maintained as 10 x 10 x 110 mm for preparing tensile specimen and 12 x 12 x 70 mm for impact specimen. Standard tensile and impact specimens were machined off from the forged square rods. Standard procedure was followed for conducting tensile test and impact test on the forged alloys. Hardness of the hot forged alloys was also measured using Rockwell hardness tester. Microstructures of the alloys were examined for correlating with the mechanical properties. Fractographs of the fractured surfaces of the tensile specimens were obtained using a scanning electron microscope. From the present study, it is contended that the alloying elements Cr, Ni and Mo have strong influence on the tensile and impact properties of the low-alloy steels studied. Among all the five alloys considered, the steel with chromium addition has exhibited the highest tensile strength with the corresponding impact strength being the least. The same alloy has also been

  18. Surface microstructures and antimicrobial properties of copper plasma alloyed stainless steel

    International Nuclear Information System (INIS)

    Bacterial adhesion to stainless steel surfaces is one of the major reason causing the cross-contamination and infection in many practical applications. An approach to solve this problem is to enhance the antibacterial properties on the surface of stainless steel. In this paper, novel antibacterial stainless steel surfaces with different copper content have been prepared by a plasma surface alloying technique at various gas pressures. The microstructure of the alloyed surfaces was investigated using glow discharge optical emission spectroscopy (GDOES) and scanning electron microscopy (SEM). The viability of bacteria attached to the antibacterial surfaces was tested using the spread plate method. The antibacterial mechanism of the alloyed surfaces was studied by X-ray photoelectron spectroscopy (XPS). The results indicate that gas pressure has a great influence on the surface elements concentration and the depth of the alloyed layer. The maximum copper concentration in the alloyed surface obtained at the gas pressure of 60 Pa is about 7.1 wt.%. This alloyed surface exhibited very strong antibacterial ability, and an effective reduction of 98% of Escherichia coli (E. coli) within 1 h was achieved by contact with the alloyed surface. The maximum thickness of the copper alloyed layer obtained at 45 Pa is about 6.5 μm. Although the rate of reduction for E. coli of this alloyed surface was slower than that of the alloyed surface with the copper content about 7.1 wt.% over the first 3 h, few were able to survive more than 12 h and the reduction reached over 99.9%. The XPS analysis results indicated that the copper ions were released when the copper alloyed stainless steel in contact with bacterial solution, which is an important factor for killing bacteria. Based on an overall consideration of bacterial killing rate and durability, the alloyed surface with the copper content of 2.5 wt.% and the thickness of about 6.5 μm obtained at the gas pressure of 45 Pa is expected

  19. A new approach to alloy compensation in a thickness measurement of high-tensile steel

    International Nuclear Information System (INIS)

    In on-line manufacturing iron-making process, several kinds of element are mixed in iron in order to meet the required quality for a final product. In this paper, the results show that the alloy compensation method is needed to improve accuracy required at thickness gauge, that is, ±0.5% at the target thickness. In addition, the alloy compensation method in measurement will be proposed in the form of correction function of each element weight percentage to be alloyed using the analyzed result of MCNP simulation program. Finally, an automatic thickness compensation method applied to the high-tensile steel product during manufacturing is introduced. (authors)

  20. High-strength economically alloyed corrosion-resistant steels with the structure of nitrogen martensite

    Science.gov (United States)

    Bannykh, O.; Blinov, V.; Lukin, E.

    2016-04-01

    The use of nitrogen as the main alloying element allowing one both to increase the corrosion resistance and mechanical properties of steels and to improve their processability is a new trend in physical metallurgy of high-strength corrosion resistant steels. The principles of alloying, which are developed for high-nitrogen steel in IMET RAS, ensure the formation of the structure, which contains predetermined amounts of martensite (70-80%) and austenite (20-30%) and is free from δ-ferrite, σ-phase, and Cr23C6 carbide. These principles were used as the base for the creation of new high-strength corrosion-resistant weldable and deformable 0Kh16AN5B, 06Kh16AN4FD, 08Kh14AN4MDB, 09Kh16AN3MF, 27Kh15AN3MD2, 40Kh13AN3M2, and 19Kh14AMB steels, which are operative at temperatures ranging from - 70 to 400°C. The developed nitrogen-containing steels compared with similar carbon steels are characterized by a higher resistance to pitting and crevice corrosion and are resistant to stress corrosion cracking. The new steels successfully passed trial tests as heavy duty articles.

  1. Pb free Zn-Sn-Ni alloy coated steel sheet for electric devices; Denshi buhinyo namari furi Zn-Sn-Ni gokin mekki gohan

    Energy Technology Data Exchange (ETDEWEB)

    Yoshihara, R.; Wake, R.; Iwamoto, Y.; Uno, Y.

    1998-05-31

    Environmental problems in recent years are increasing demand for freedom from lead. Nippon Steel developed Zn-Sn-Ni alloy coated steel sheet that improves on the corrosion resistance and whisker formation of electrolytic tinplate traditionally used as coated steel for electronic parts. The zinc, tin, and nickel are sequentially applied to steel strip on an electrolytic tinning line and are subjected to a thermal diffusion alloying treatment by a reflow unit to form a Zn-Sn-Ni alloy mainly composed of Sn and Zn. The Zn-Sn-Ni alloy coated steel sheet features excellent corrosion resistance, solderability and whisker resistance as coated steel sheet for electronic parts. (author)

  2. Plastic behaviour and microstructure characterization high manganese aluminium alloyed steel for the automotive industry

    Directory of Open Access Journals (Sweden)

    D. Kuc

    2012-03-01

    Full Text Available Purpose: Automotive industry constantly demands high-strength steels which are characterized by the energy absorption possibilities during a collision. Such materials may, in the future, replace the currently used conventional steels. The groups of steels which meet these criteria are the austenitic steels and austenitic-ferritic steels with high manganese content (15-30% and high aluminium content (1-9%. Design/methodology/approach: Susceptibility of steel to cracking at high temperatures was tested on Gleeble 3800 simulator: zero resistance temperature was determined (TZW, zero plasticity temperature was determined (TZP, plasticity reversal temperature was determined (TNP. Research was completed by determination of steel plasticity and stress applying in next stage the deformation of samples in temperature from 850 to 1175°C. This temperature range corresponding with the field of parameters of plastic processing. For samples after tension the ultimate tensile strength was determined (Rm together with contraction (Z. Character of fractures of stretched samples was tested with the use of scanning microscope Hitachi S-4200.Findings: The tests show that the tested steel is characterised by relatively lower temperatures in comparison with low-alloyed steels. Tested steel has high plasticity in temperature wear to temperature of plastic processing 1150-800°C.Practical implications: The obtained steel is characterised by beneficial properties which outbalance the austenitic steels type TWIP and may be applied in vehicle construction on elements connected with safety.Originality/value: Conducted simulation will be helpful by elaboration of technology of continuous casting and the choice of the right parameters for plastic processing of high-manganese steel with aluminium.

  3. 75 FR 26273 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China

    Science.gov (United States)

    2010-05-11

    ... COMMISSION Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China AGENCY... pipe (``seamless SLP pipe''), provided for in subheadings 7301.19.10, 7304.19.50, 7304.31.60, 7304.39... China of seamless SLP pipe, and that such products are being sold in the United States at less than...

  4. Practical measurement of silicon in low alloy steels by differential pulse stripping voltammetry

    International Nuclear Information System (INIS)

    A sensitive differential pulse anodic stripping voltammetry has been adapted to allow the determination of Si in low-alloy steels using a hanging mercury drop electrode. The method has been qualified using certified ASTM standards and is now running in routine. The present report describes the experimental details, thereby allowing the reader to carry out the measurements precisely. (author)

  5. Inverse Processing of Undefined Complex Shape Parts from Structural High Alloyed Tool Steel

    Czech Academy of Sciences Publication Activity Database

    Monková, K.; Monka, P.; Hloch, Sergej

    -, č. 1 (2014), s. 1-11. ISSN 1687-8132 Institutional support: RVO:68145535 Keywords : 3D digitization * complex shape parts * high alloyed tool steel Subject RIV: JQ - Machines ; Tools Impact factor: 0.575, year: 2014 http://www.hindawi.com/journals/ame/aip/478748/

  6. Corrosion resistance of Zn-Co-Fe alloy coatings on high strength steel

    NARCIS (Netherlands)

    Lodhi, Z.F.; Mol, J.M.C.; Hovestad, A.; Hoen-Velterop, L. 't; Terryn, H.; Wit, J.H.W.de

    2009-01-01

    The corrosion properties of electrodeposited zinc-cobalt-iron (Zn-Co-Fe) alloys (up to 40 wt.% Co and 1 wt.% Fe) on steel were studied by using various electrochemical techniques and compared with zinc (Zn) and cadmium (Cd) coatings in 3.5% NaCl solution. It was found that with an increase in Co con

  7. Research and development of steel and alloy tubes and pipe for nuclear services

    International Nuclear Information System (INIS)

    This company has been engaged in the research and development of steel and alloy tubes and pipe for nuclear services, among which the results for four products will be described as follows: (1) Zircaloy tubes for nuclear fuel cladding : the improvement of manufacturing and inspection techniques, the research on improvement in quality of the product (corrosion resistance, texture, hydride precipitation characteristics, mechanical properties, etc.), and irradiation test. (2) Steam generator tubes for a high temperature gas cooled reactor for power generating : high temperature strength, structure change, and oxidation resistance and weldability of Fe-32Ni-20Cr-Ti-Al alloy. (3) Heat resistant alloys for heat exchanger tubes in nuclear steel-making : high temperature strength and oxidation resistance of several kinds of heat resistant alloys, and the introduction of newly installed helium circulating loop system for material testing. (4) Ultra-high strength steel pipe for manufacturing equipment of nuclear fuel material : results of research on improvement in quality of 300ksi and 350ksi grade maraging steels. (auth.)

  8. Study made of corrosion resistance of stainless steel and nickel alloys in nuclear reactor superheaters

    Science.gov (United States)

    Greenberg, S.; Hart, R. K.; Lee, R. H.; Ruther, W. E.; Schlueter, R. R.

    1967-01-01

    Experiments performed under conditions found in nuclear reactor superheaters determine the corrosion rate of stainless steel and nickel alloys used in them. Electropolishing was the primary surface treatment before the corrosion test. Corrosion is determined by weight loss of specimens after defilming.

  9. Time-temperature-precipitation diagrams of carbide evolution in low alloy steels

    Czech Academy of Sciences Publication Activity Database

    Janovec, J.; Svoboda, Milan; Výrostková, A.; Kroupa, Aleš

    2005-01-01

    Roč. 402, - (2005), s. 288-293. ISSN 0921-5093 Institutional research plan: CEZ:AV0Z20410507 Keywords : low alloy steels * carbides * transmission electron microscopy Subject RIV: JG - Metallurgy Impact factor: 1.347, year: 2005

  10. 78 FR 2658 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Rescission of Antidumping Duty...

    Science.gov (United States)

    2013-01-14

    ...; Opportunity To Request Administrative Review, 77 FR 59894 (October 1, 2012). \\2\\ See Letter from Nucor... Countervailing Duty Administrative Reviews and Request for Revocation in Part, 77 FR 71575 (December 3, 2012). \\4... International Trade Administration Carbon and Certain Alloy Steel Wire Rod From Mexico: Rescission...

  11. Alloy 31 - a high alloyed Ni-Cr-Mo-steel - properties and applications for the process industry: Alloy 31 - visoko legirano Ni-Cr-Mo jeklo - lastnosti in aplikacije za procesno industrijo:

    OpenAIRE

    Brill, U.; Mast, Ralph; Rommerskirchen, I.; Schambach, L.

    1998-01-01

    Alloy 31 (Nicrofer 3127 hMo) is an austentic nickel-chromium-molybdenum steel comprising about 0.2 wt-% nitrogen to stabilize the austenitic structure. The alloy was developed to fill the gap between the commercial stainless steels and the nickel-base alloys. It is a material for many high-severity applications where conventional stainless steels have proven unadequate. On the other hand, Alloy 31 shows a high resistance to pitting and crevice corrosion in neutral and acid aqueous solutions, ...

  12. Segregation of alloying elements in thermomechanically rolled medium-Mn multiphase steels

    Directory of Open Access Journals (Sweden)

    A. Grajcar

    2012-12-01

    Full Text Available Purpose: The aim of the paper is to assess the tendency of alloying elements to macro- and microsegregation during hot-forging and successive thermomechanical rolling of medium-Mn Al-bearing steel sheets.Design/methodology/approach: The macro- and microsegregation of alloying elements was assessed by EDS and WDS measurements across the thickness of the roughly-forged flats and thermomechanically processed 3.3 mm sheets. The microstructure was revealed using combined methods of optical microscopy (OM and scanning electron microscopy (SEM. Morphological features of microstructural constituents were discussed with focusing on retained austenite. Findings: It was found that the final multiphase microstructure is mainly dependent on the Mn content and the effect of Nb microaddition is relatively low. The 3Mn steels possess very fine bainite-based microstructures whereas the steels containing 5% Mn are characterized by lath bainitic-martensitic microstructures. All the steels contain retained austenite as fine granules or layers located between bainitic ferrite laths. Some fraction of martensite-austenite (M-A islands was also identified. The tendency of Mn and Al to macrosegregation was found after the initial hot-forging. It disappears after successive rough and thermomechanical rolling whereas thin martensite and martensite-austenite microbands as a result of Mn microsegregation locally occur.Research limitations/implications: Further investigations are required to quantify the local changes of chemical composition especially in formed microbands and X-ray quantitative phase analysis should be applied to assess a fraction of retained austenite.Practical implications: The knowledge of the macro- and microsegregation of alloying elements in advanced medium-Mn steels containing retained austenite can be useful in designing the thermomechanical rolling procedures of multiphase steel sheets.Originality/value: A problem of macro- and microsegregation of

  13. Corrosion of nickel alloys and stainless steels in polluted or confined PWR environments

    International Nuclear Information System (INIS)

    This document addresses the issue of corrosion of materials used in PWR nuclear reactors, notably in steam generators which have been particularly affected by this kind of degradation due to a progressive accumulation of impurities. The authors first present the different materials used in secondary circuit and in auxiliary circuits of PWRs: carbon steels and low alloyed steels, nickel alloys, stainless steels, and other materials. They discuss the degradation of steam generator tubes by corrosion: corrosion environments, types of corrosion (wastage, pitting, intergranular stress corrosion cracking), and influence of the environment and of the microstructure. They also propose a brief overview of modelling efforts in the case of the 600 alloy, and indicates measures to mitigate the tube degradation by corrosion (water treatment, better design of steam generators and secondary circuit, improvement of corrosion resistance). The next part addresses the degradation by stress corrosion cracking of stainless steels in polluted environments in PWRs reactors: return on experience, stress corrosion cracking in media contaminated by impurities (intergranular corrosion of sensitized or work hardened steels, transgranular corrosion by chloride ions, corrosion by diluted sulphate + chloride, corrosion in concentrated boric acid solutions)

  14. Mechanical Behavior of Two High Strength Alloy Steels Under Conditions of Cyclic Tension

    Science.gov (United States)

    Srivatsan, T. S.; Manigandan, K.; Sastry, S.; Quick, T.; Schmidt, M. L.

    2014-01-01

    The results of a recent study aimed at understanding the conjoint influence of load ratio and microstructure on the high cycle fatigue properties and resultant fracture behavior of two high strength alloy steels is presented and discussed. Both the chosen alloy steels, i.e., 300M and Tenax™ 310 have much better strength and ductility properties to offer in comparison with the other competing high strength steels having near similar chemical composition. Test specimens were precision machined from the as-provided stock of each steel. The machined specimens were deformed in both uniaxial tension and cyclic fatigue under conditions of stress control. The test specimens of each alloy steel were cyclically deformed over a range of maximum stress at two different load ratios and the number of cycles to failure recorded. The specific influence of load ratio on cyclic fatigue life is presented and discussed keeping in mind the maximum stress used during cyclic deformation. The fatigue fracture surfaces were examined in a scanning electron microscope to establish the macroscopic mode and to concurrently characterize the intrinsic features on the fracture surface. The conjoint influence of nature of loading, maximum stress, and microstructure on cyclic fatigue life is discussed.

  15. Cavitation erosion behavior of WC coatings on CrNiMo stainless steel by laser alloying

    Institute of Scientific and Technical Information of China (English)

    Xiao-bin Zhang; Chang-sheng Liu; Xiao-dong Liu; Jiang Dong; Bo Yu

    2009-01-01

    The WC powder was precoated on the surface of CrNiMo stainless steel and then made into an alloying layer by using the laser alloying technique.Phases in the layers were investigated by X-ray diffraction (XRD) analysis and surface morphologies after cavitation erosion were observed with the help of scanning electron microscopy (SEM).The cavitation erosion behavior of the CrNiMo stainless steel and WC laser alloying layer in distilled water was tested with the help of ultrasonic vibration cavitation ero-sion equipment.The results showed that the thickness of the laser alloying layer was about 0.13 mm.The layer had a dense micro-structure, metallurgically bonded to the substrate, and no crack had been found.The cavitation erosion mass loss rate of the laser al-loying layer was only 2/5 that of the CrNiMo stainless steel.The layer had better cavitation resistance properties because of its met-allurgical combination and the strengthening effects of the precipitate phases.

  16. Analysis Of The Austenite Grain Growth In Low-Alloy Boron Steel With High Resistance To Abrasive Wear

    OpenAIRE

    Białobrzeska B.; Dudziński W.

    2015-01-01

    Today low-alloy steels with boron achieve high resistance to abrasive wear and high strength. These features are obtained by using advanced technology of manufacturing. This makes boron steels increasingly popular and their application more diverse. Application of these steels can extend the lifetime of very expensive machine construction in many industries such as mining, the automotive, and agriculture industries. An interesting subgroup of these materials is steel with boron intended for h...

  17. Diffusion-controlled wear of steel friction stir welding tools used on aluminum alloys

    Science.gov (United States)

    Tarasov, S. Yu.; Kalashnikova, T. A.; Kalashnikov, K. N.; Rubtsov, V. E.; Eliseev, A. A.; Kolubaev, E. A.

    2015-10-01

    The worn surfaces of steel instruments used for friction stir welding on AMg5M aluminum alloy have been examined. An adhesion transfer layer resulted on the steel tool surface from welding the aluminum-magnesium alloy. Diffusion between this layer and steel base metal resulted in formation of an intermetallic Fe-Al layer (IMC). The hardness of the IMC has been measured using a nanohardness tester. It was found that the IMC layers maximum hardness changed from 998 to 1698 HV. The continuous IMC layers may serve as a wear-resistant coating, however, the IMC were also found in the shape of spikes directed into the tool's body, which created conditions for wear particle formation by fracture.

  18. Effects of milling process and alloying additions on oxide particle dispersion in austenitic stainless steel

    International Nuclear Information System (INIS)

    An oxide dispersion strengthened (ODS) austenitic stainless steel was developed by mechanical alloying (MA) of advanced SUS316 stainless steel. A nano-characterization was performed to understand details of the effect of minor alloying elements in the distribution of dispersoids. It is shown that Y2O3 particles dissolve into the austenitic matrix after the MA for 6 h. Annealing at 1073 K or higher temperatures result in a distribution of fine oxide particles in the recrystallized grains in the ODS austenitic stainless steel. Additions of Hafnium or Zirconium led to the distribution of finer oxide particles than in samples without these elements, resulting in an increase in the hardness of the samples. The most effective concentration of Hf and Zr to increase the hardness was 0.6 and 0.2–0.3 wt%, respectively

  19. MODELING OF AUSTENITE GRAIN SIZE IN LOW-ALLOY STEEL WELD METAL

    Institute of Scientific and Technical Information of China (English)

    A.G.Huang; Y.S.Wang; Z.Y.Li; J.G.Xiong; Q.Hu

    2004-01-01

    The size of austenite grain hassignificant effects on components and proportions of various ferrites in low-alloy steel weld metal.Therefore,it is important to determine the size of austenite grain in the weld metal.In this paper,a model based upon the carbon diffusion rate is developed for computing austenite grain size in low-alloy steel weld metal during continuous cooling.The model takes into account the effects of the weld thermal cycles,inclusion particles and various alloy elements on the austenite grain growth.The calculating results agree reasonably with those reported experimental observations.The model demonstrates a significant promise to understand the weld microstructure and properties based on the welding science.

  20. Simultaneous Co-deposition of Zn-Mg Alloy Layers on Steel Strip by PVD Process

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Yeob [POSCO Technical Research Laboratories, Gwangyang (Korea, Republic of); Goodenough, Mark [Strategic Marketing, Tata Steel, Warwickshire (United Kingdom)

    2011-12-15

    This is the first release of an interim report on the development of coating technology of Zn-Mg alloy layers on steel strip by EML-PVD (electromagnetic levitation - physical vapor deposition) process in an air-to-air type continuous PVD pilot plant. It intends to introduce a basic principle of the EML-PVD process together with the high speed PVD pilot plant built in Posco. Due to the agitation effect provided by the high frequency induction coil, simultaneous evaporation of Zn and Mg from a droplet could produce alloy coating layers with Mg content of 6% to 12% depending on the composition of the droplet inside the coil. For its superior corrosion resistance, Zn-Mg alloy coated steel would be a very promising material for automotive, electrical appliances, and construction applications.

  1. Nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel and stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Moore, D.G.; Sorensen, N.R.

    1998-02-01

    This report presents a nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel alloys from stainless steel alloys as well as an evaluation of cleaning techniques to remove a thermal oxide layer on aircraft exhaust components. The results of this assessment are presented in terms of how effective each technique classifies a known exhaust material. Results indicate that either inspection technique can separate inconel and stainless steel alloys. Based on the experiments conducted, the electrochemical spot test is the optimum for use by airframe and powerplant mechanics. A spot test procedure is proposed for incorporation into the Federal Aviation Administration Advisory Circular 65-9A Airframe & Powerplant Mechanic - General Handbook. 3 refs., 70 figs., 7 tabs.

  2. Aging of maraging steel welds during aluminium alloy die casting

    OpenAIRE

    Klobčar, Damjan; Pleterski, Matej; Taljat, Boštjan; Kosec, Ladislav; Tušek, Janez

    2015-01-01

    The aim of this study is to evaluate precipitation annealing of 18% Ni maraging steel repair welds during aluminium die casting and to predict the prolonged in-service tool life. The emphasis of this study is the influence ofpost-weld precipitation annealing heat treatment and aluminium die casting thermal cycling on metallurgical and mechanical properties. A series of specimens of 1.2344 tool steel is prepared to which 1.6356 maraging steel is GTA weld cladded. Analysis of weld microstructur...

  3. Influence of Hydrodynamic Structure on Mixing Time of Alloy Additions with Liquid Steel in One Strand Tundish

    Directory of Open Access Journals (Sweden)

    Cwudziński A.

    2016-03-01

    Full Text Available The knowledge of the hydrodynamic pattern aids in designing new and modernizing existing tundishes. The device under examination is an one-strand tundish of a capacity of 30 Mg. Computer simulation of the liquid steel flow, tracer and alloy addition behaviour in turbulent motion conditions was done using the Ansys-Fluent® computer program. The hydrodynamic conditions of steel flow were determined based on the distribution of the characteristics of tundish liquid steel residence time distribution (RTD. The alloy addition was introduced to the liquid steel by the pulse-step method. Based on computer simulations carried out, steel flow fields and RTD and mixing curves were obtained, and the shares of stagnant volume flow and active flow and the mixing time were computed. Dispersion of the alloy addition in liquid steel during its flow through the tundish is a dynamic process which is determined by the hydrodynamic conditions occurring in the tundish working space.

  4. Microstructures and mechanical property of laser butt welding of titanium alloy to stainless steel

    International Nuclear Information System (INIS)

    Highlights: • The laser direct butt welding of titanium alloy to stainless steel is realized. • The interfacial microstructures of the joints are confirmed. • The weldability is better when laser beam is offset toward titanium than steel. • The highest tensile strength of the joint reaches to 150 MPa. - Abstract: Laser butt welding of titanium alloy to stainless steel was performed. The effect of laser-beam offsetting on microstructural characteristics and fracture behavior of the joint was investigated. It was found that when the laser beam is offset toward the stainless steel side, it results in a more durable joint. The intermetallic compounds have a uniform thickness along the interface and can be divided into two layers. One consists of FeTi + α-Ti, and other consists of FeTi + Fe2Ti + Ti5Fe17Cr5. When laser beam is offset by 0 mm and 0.3 mm toward the titanium alloy side, the joints fracture spontaneously after welding. Durable joining is achieved only when the laser beam is offset by 0.6 mm toward the titanium alloy. From the top to the bottom of the joint, the thickness of intermetallic compounds continuously decreases and the following interfacial structures are found: FeAl + α-Ti/Fe2Ti + Ti5Fe17Cr5, FeAl + α-Ti/FeTi + Fe2Ti + Ti5Fe17Cr5 and FeAl + α-Ti, in that order. The tensile strength of the joint is higher when the laser beam is offset toward the stainless steel than toward the titanium alloy, the highest observed value being 150 MPa. The fracture of the joint occurs along the interface between two adjacent intermetallic layers

  5. Effect of microstructure on the susceptibility of low-alloy steels to hydrogen attack

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R.O.

    1981-08-01

    In an alloy steel in which one or more alloy additions stabilize the carbide phase, the carbon activity depends on the microstructure and the prior thermal history. The carbon activity is a major factor in the susceptibility of such steels to form internal methane bubbles when heated in high-pressure hydrogen. Thus one can expect to vary the susceptibility to hydrogen attack of a given steel by its prior treatment. The problem has two aspects. First, one needs to be able to calculate the equilibrium carbon activity when the steel is in internal equilibrium. A computer program in the appendix of this report takes care of part of this problem. When the thermodynamics of the mixed carbide phase is adequately modeled, then this problem can be solved. The second part is the rate of approach to equilibrium. An analysis of the rate of coarsening of carbides in such steels shows that this rate is enhanced by a fine carbide dispersion. Such a fine dispersion is also desirable for the maximum strength. Thus, we believe that under favorable circumstances the resistance to hydrogen attack can be enhanced by suitable thermal treatments of the steels used for the pressure vessels for hydrogen service. 12 figures.

  6. Plastic localization phenomena in a Mn-alloyed austenitic steel

    OpenAIRE

    Matteis, Paolo; Firrao, Donato; Scavino, Giorgio; Russo Spena, Pasquale

    2010-01-01

    A 0.5 wt pct C, 22 wt pct Mn austenitic steel, recently proposed for fabricating automotive body structures by cold sheet forming, exhibits plastic localizations (PLs) during uniaxial tensile tests, yet showing a favorable overall strength and ductility. No localization happens during biaxial Erichsen cupping tests. Full-thickness tensile and Erichsen specimens, cut from as-produced steel sheets, were polished and tested at different strain rates. During the tensile tests, the PL phenomena co...

  7. Influence of technetium on the microstructure of a stainless steel-zirconium alloy

    International Nuclear Information System (INIS)

    Stainless steel-zirconium alloys are being developed for the disposal of metallic waste generated during the electrometallurgical treatment of spent Experimental Breeder Reactor (EBR-II) fuel. The metallic waste contains the fission product technetium, which must be incorporated into a stable waste form matrix to prevent its release into the environment. The baseline waste form for metallic waste from EBR-II fuels is a stainless steel-15 wt% zirconium (SS-15Zr) alloy. The microstructure of SS-15Zr alloys containing 2 wt% technetium was characterized using a combination of microscopy, spectroscopy, diffraction, and chemical analysis techniques. Peaks corresponding to the iron solid solutions ferrite and austenite, ZrFe2-type Laves polytypes C36 and C15, and an Fe23Zr6-type intermetallic were identified in diffraction patterns of the alloy. Discrete technetium-rich phases were not observed either in diffraction patterns or in the microstructure; the element partitioned into various phases of the SS-15Zr alloy. Technetium favors ferrite and austenite over the Zr-based intermetallics. The lattice parameters of the Zr-based intermetallics are smaller than those in an alloy without technetium, which appears to substitute at the zirconium sites of the intermetallic lattice

  8. Oxidation kinetics of high strength low alloy steels at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Talekar, Anjali [Materials Science and Engineering, Chemical and Metallurgical Engineering Department, MS 388, University of Nevada, 1664 North Virginia Street, Reno, NV 89557 (United States); Chandra, Dhanesh [Materials Science and Engineering, Chemical and Metallurgical Engineering Department, MS 388, University of Nevada, 1664 North Virginia Street, Reno, NV 89557 (United States)], E-mail: dchandra@unr.edu; Chellappa, Raja [Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, Washington, DC 20015 (United States); Daemen, Jaak [Mining Engineering Department, University of Nevada, Reno, NV 89557 (United States); Tamura, Nobumichi; Kunz, Martin [Advanced Light Source, Lawrence Berkeley National Laboratories, MS 2R0222, Berkeley, CA 94720 (United States)

    2008-10-15

    High strength low alloy (HSLA) steels are candidate Rockbolt materials for use as underground roof supports at Yucca Mountain nuclear waste repository. Oxidation kinetics of International Rollforms Split Set Friction Rock Stabilizers (SS46), and Swellex Mn24 steels have been determined by temperature modulated thermogravimetry at temperatures ranging between 600 and 900 deg. C in pure oxygen atmosphere for 100 hr. The imposed sinusoidal temperature modulations ({+-}5 deg. C for a period of 1 cycle per 200 s) on the isothermal temperature did not have any noticeable effect on the weight gain characteristics during oxidation. Weight gain data on the steels indicate two distinct regions with different oxidation profiles, where a definite change in rates of oxidation is observed: a first oxidation regime where the steels followed a rate law y = kt{sup 0.40-0.63} (changing index of rate law depending upon steel and temperature) and a second stage oxidation regime that follows the parabolic law. The results of characterization of the oxide films using SEM/EDAX, X-ray diffraction and Synchrotron white beam X-ray microdiffraction are presented. The oxidation data of the steels presented here is expected to be useful for characterizing those steels for use in underground rock bolt system and as roof support for the DOE proposed Yucca Mountain Nuclear Waste Repository. To the best of our knowledge this is the first time thermogravimetric studies of this kind have been done on these steels.

  9. Compatibility studies of AISI type 316 stainless steel with lead-lithium eutectic alloy

    International Nuclear Information System (INIS)

    Spent fuel subassemblies from the Fast Breeder Test Reactor (FBTR) are to be stored in leak tight cotainers until they are required to be sent for reprocessing. Use of advanced fuels like uranium carbides and plutonium carbides, which are known to be highly chemically active with oxygen and moisture demands adequate leak tightness during long term storage to avoid undesirable chemical reactions. Use of low melting alloys which acts as liquid/solid sealants in the storage containers in which fuel subassemblies are to be kept is being considered for this purpose. Lead-lithium (0.7 wt % lithium) eutectic alloy was chosen as one of the candidate alloys for the purpose on the basis of theoretical assessments. The candidate sealing alloy should have good compatibility with the structural materials of fuel subassemblies as well as the fuel and fission products. AISI type 316 stainless steel in solution annealed, ten and twenty percent cold worked condition is the clad and wrapper material used for the fabrication of fuel pins and subassemblies. Compatibility studies between eutectic Pb-Li alloy and AISI type 316 stainless steel material in the above conditions were undertaken at different temperatures and time durations. The studies indicate that the tensile properties of AISI type 316 stainless steel are not subject to any serious jeopardisation through contact with this molten Pb-Li eutectic alloy for periods extending even upto 7000 hours at 873 K. Thus use of Pb-Li eutectic alloy would be suitable for the storage of irradiated fuel. (author). 16 refs., 38 figs., 3 tabs

  10. The research of modification process of steel Hadfield integrated alloy ferroalumisilicocalcium (Fe-Al-Si-Сa/FASC

    Directory of Open Access Journals (Sweden)

    A. Z. Issagulov

    2016-07-01

    Full Text Available There is article discusses the process of modification of high-manganese steel, Hadfield, which will significantly increase the yield of the casting at the stage of melting and casting the steel. The steel modification performed integrated alloy FASC (ferroalumisilicocalcium in an amount of 03 - 0,5% by weight of the metal. The integrated alloy unlike traditional methods of modification leads to globalizatsii and purification of steel from nonmetallic inclusions and for grinding grains of austenite, thereby greatly increases its mechanical properties.

  11. Formation of gradient surface layers on high speed steel by laser surface alloying process

    Directory of Open Access Journals (Sweden)

    M. Bonek

    2012-12-01

    Full Text Available Purpose: The purpose of this research paper is focused on the high speed steel HS6-5-3-8 surface layers improvement properties using HPDL laser. The paper present laser surface technologies, investigation of structure and properties of the high speed steel alloying with the WC, VC, TiC, SiC, Si3N4 and Al2O3 particles using high power diode laser HPDL.Design/methodology/approach: Investigation indicate the influence of the alloying elements on the structure and properties of the surface layer of investigated steel depending on the kind of alloying carbides, oxides, nitrides and power implemented laser (HPDL.Findings: Laser alloying of surface layer of investigated steel without introducing alloying additions into liquid molten metal pool, in the whole range of used laser power, causes size reduction of dendritic microstructure with the direction of crystallization consistent with the direction of heat carrying away from the zone of impact of laser beam. In the effect of laser alloying with powder of the WC, VC, TiC, SiC, Si3N4and Al2O3 particles occurs size reduction of microstructure as well as dispersion hardening through fused in but partially dissolved particles and consolidation through enrichment of surface layer in alloying additions coming from dissolving elements. Introduced particles of carbides, oxides, nitrides and in part remain undissolved, creating conglomerates being a result of fusion of undissolved powder grains into molten metal base. In effect of convection movements of material in the liquid state, conglomerates of carbides arrange themselves in the characteristic of swirl. Practical implications: Laser surface modification has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones.Originality/value: The structural mechanism was determined of surface layers development, effect was studied of alloying

  12. Influence of Alloying Elements Corrosion Resistance of Cold on Mechanical Properties and Rolled C-Mn-Si TRIP Steels

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ling-yun; WU Di; LI Zhuang

    2012-01-01

    The rust layer plays an important role in the corrosion of steel in chlorinated environments. Salt spray, po- tentiodynamic polarization curve and tensile test were conducted in laboratory for the specimens after two-stage heat treatment. The influence of the alloying elements on mechanical properties and corrosion resistance of three kinds of steels was investigated by observing the microstructure and the morphologies of rust layer. The results show that the highest value (29%) of total elongation for steel A is obtained. The mechanical property of the specimen for steel C exhibits best strength ductility balance (21 384 MPa ·%) because of the presence of the multiphase microstructures after a two-stage heat treatment and the addition of the alloying elements. The corrosion products are known to be a complex mixture of Fe3O4 , Fe2O3 and α-FeOOH for steel C. The presence of the alloying elements results in the for mation of compact and dense rust layers in steel B and C. Passive film protects the substrate of TRIP (transformation induced plasticity) steel containing a complex mix of multiphase. Superior corrosion performance is exhibited for steel C with low alloying contents due to the enrichment of alloying elements within the rust layers.

  13. Moessbauer study of the annealing effect on low-alloyed steels

    International Nuclear Information System (INIS)

    Structural analyses of Fe-Cr and Fe-Cr-Ni low-alloyed steels before and after annealing at 600 deg. C using Moessbauer spectrometry, X-ray diffraction and scanning electron microscopy are reported. At the received state, the two steels present a fine bainitic microstructure with equal hardness. From Moessbauer analysis, two iron sites are identified as substitutional by Cr, Mo, Ni atoms and as insertional by carbon in bainitic ferrite. Both sites are locally deformed by residual stresses. The presence of small quantities of retained austenite and ε carbide has been observed. Annealing for one hour at 600 deg. C causes a decrease in hardness for both steels with a decrease of retained austenite. After longer time of annealing, precipitation of (Fe,Ni)23C6 occurs in the Fe-Cr-Ni steel and increases hardness

  14. Alloying and heat treatment optimization of Fe/Cr/C steels for improved mechanical properties

    International Nuclear Information System (INIS)

    The effects of alloying elements and heat treatments on the microstructural changes and strength-toughness properties were investigated in optimization of vacuum melted Fe/Cr/C base steels. The structure of the steels in the as-quenched conditions consisted of highly dislocated autotempered lath martensite (strong phase) and thin continuous interlath films of retained austenite (tough phase). It has been emphasized again that the mechanical properties of the steels are sensitive to the amount and the stability of retained austenite. To increase the stability of retained austenite in the as-quenched condition 2 w/o Mn or 2 w/o Ni was added to the base steel, viz., Fe/3Cr/0.3C. Partial replacement of Cr by about 0.5 w/o Mo did not alter the beneficial microstructure

  15. Change of tensile behavior of a high-strength low-alloy steel with tempering temperature

    International Nuclear Information System (INIS)

    The tensile behavior of a high-strength low-alloy (HSLA) steel after tempering at different temperatures from 200 to 700 deg. C was investigated. The steel showed similar tensile behavior with almost no change in strength for tempering below 400 deg. C. However, when the tempering temperature was increased from 500 to 650 deg. C, the steel displayed not only a decrease in strength, but also gradually the upper yield points and lower strain-hardening ability. When the tempering temperature was increased up to 700 deg. C, the steel exhibited a 'round roof' shaped tensile curve and a high strain-hardening exponent. These interesting phenomena of tensile behavior are well explained in view of the interactions of mobile dislocations and dissolved C and N atoms and their effects on the strain-hardening exponent.

  16. Change of tensile behavior of a high-strength low-alloy steel with tempering temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yan Wei; Zhu Lin [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Sha Wei [Metals Research Group, School of Planning, Architecture and Civil Engineering, Queen' s University of Belfast, Belfast BT7 1NN (United Kingdom); Shan Yiyin, E-mail: yyshan@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Yang Ke [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2009-08-20

    The tensile behavior of a high-strength low-alloy (HSLA) steel after tempering at different temperatures from 200 to 700 deg. C was investigated. The steel showed similar tensile behavior with almost no change in strength for tempering below 400 deg. C. However, when the tempering temperature was increased from 500 to 650 deg. C, the steel displayed not only a decrease in strength, but also gradually the upper yield points and lower strain-hardening ability. When the tempering temperature was increased up to 700 deg. C, the steel exhibited a 'round roof' shaped tensile curve and a high strain-hardening exponent. These interesting phenomena of tensile behavior are well explained in view of the interactions of mobile dislocations and dissolved C and N atoms and their effects on the strain-hardening exponent.

  17. High temperature corrosion of low and high alloy steels under molten carbonate fuel cell conditions

    Energy Technology Data Exchange (ETDEWEB)

    Biedenkopf, P.; Spiegel, M.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    1997-08-01

    The corrosion behavior of eight low and high alloy steels was investigated under simulating the conditions at the cathode of a molten carbonate fuel cell at 650 C. Different Li-containing iron oxides (LiFeO{sub 2} and LiFe{sub 5}O{sub 8}) were formed in contact with the eutectic (Li, K)-carbonate melt depending on the Cr-content of the steel. These oxides show low solubility in the melt and protect the metallic material against further corrosive attack. Fast growing scales of Fe{sub 3}O{sub 4} and LiFe{sub 5}O{sub 8} were observed on the low alloy ferritic steel 10 CrMo 9 10. Higher alloy steels form LiFeO{sub 2} in contact with the melt and mixed Fe-Cr-spinels underneath. Steels with Cr-contents over 20 wt.% Cr form a mixed LiCr{sub 1-x}Fe{sub x}O{sub 2} and LiCrO{sub 2} layer in contact with the metal. Marker experiments on the commercial steel 1.4404 (X2 CrNiMo 17 13 2) show that the outer LiFeO{sub 2} layer grows mainly by outward diffusion of iron ions (Fe{sup 3+}), whereas the inner (Fe,Ni)Cr{sub 2}O{sub 4} spinel layer grows inward. After 500 hours, LiFe{sub 5}O{sub 8} was formed between the spinel and the LiFeO{sub 2} layer, but it had disappeared after several thousand hours of exposure as it was fully transformed to LiFeO{sub 2}. Co-containing LiFeO{sub 2} was found after 500 hours on the high Co-containing steel 1.4971 (X12 CrCoNi 21 20), but is not stable after several thousand hours exposure. Co diffuses outward to form a protective LiCoO{sub 2} layer of a few microns in thickness. Protective Cr{sub 2}O{sub 3} layers were not observed on steels with high Co-content ({>=}25 wt.% Cr) due to peroxide ions in the melt, which cause oxidation Cr{sub 2}O{sub 3} and flux to chromate, which is highly soluble in the melt. Further quantitative investigations on total corrosion considering the chromate formation have shown that high alloy steels with high amounts of Cr form mainly K{sub 2}CrO{sub 4}. (orig.) 22 refs.

  18. High temperature corrosion of low and high alloy steels under molten carbonate fuel cell conditions

    International Nuclear Information System (INIS)

    The corrosion behavior of eight low and high alloy steels was investigated under simulating the conditions at the cathode of a molten carbonate fuel cell at 650 C. Different Li-containing iron oxides (LiFeO2 and LiFe5O8) were formed in contact with the eutectic (Li, K)-carbonate melt depending on the Cr-content of the steel. These oxides show low solubility in the melt and protect the metallic material against further corrosive attack. Fast growing scales of Fe3O4 and LiFe5O8 were observed on the low alloy ferritic steel 10 CrMo 9 10. Higher alloy steels form LiFeO2 in contact with the melt and mixed Fe-Cr-spinels underneath. Steels with Cr-contents over 20 wt.% Cr form a mixed LiCr1-xFexO2 and LiCrO2 layer in contact with the metal. Marker experiments on the commercial steel 1.4404 (X2 CrNiMo 17 13 2) show that the outer LiFeO2 layer grows mainly by outward diffusion of iron ions (Fe3+), whereas the inner (Fe,Ni)Cr2O4 spinel layer grows inward. After 500 hours, LiFe5O8 was formed between the spinel and the LiFeO2 layer, but it had disappeared after several thousand hours of exposure as it was fully transformed to LiFeO2. Co-containing LiFeO2 was found after 500 hours on the high Co-containing steel 1.4971 (X12 CrCoNi 21 20), but is not stable after several thousand hours exposure. Co diffuses outward to form a protective LiCoO2 layer of a few microns in thickness. Protective Cr2O3 layers were not observed on steels with high Co-content (≥25 wt.% Cr) due to peroxide ions in the melt, which cause oxidation Cr2O3 and flux to chromate, which is highly soluble in the melt. Further quantitative investigations on total corrosion considering the chromate formation have shown that high alloy steels with high amounts of Cr form mainly K2CrO4. (orig.)

  19. Phase stability of laves intermetallics in a stainless steel-zirconium alloy

    International Nuclear Information System (INIS)

    Phase transformations occurring in a stainless steel-15 wt% zirconium (SS-15Zr) alloy were studied by in situ neutron diffraction. Neutron diffraction patterns as a function of time were obtained on alloys that were held at various elevated temperatures (1084-1275 C). As-cast SS-15Zr alloys contain ferrite, austenite, ZrFe2-type Laves polytypes C36 and C15, and small amounts of a Fe23Zr6-type intermetallic. Annealing at high temperatures resulted in an increase of the Fe23Zr6, intermetallic content. The C15 Laves polytype is the equilibrium phase for T ≤ 1230 C; C36 is the stable polytype at higher temperatures (∼1275 C). Phase changes were slow for temperatures <1100 C.These findings have important implications for use of the SS-15Zr alloy as a nuclear waste form

  20. X-ray photoelectron spectroscopy investigations of zinc-magnesium alloy coated steel

    International Nuclear Information System (INIS)

    The coating layer composition depth profiles and element chemical states of zinc-magnesium alloy coated steel were investigated by X-ray photoelectron spectroscopy depth profiling. Through the analysis of photoelectron signals and Auger signals of different elements on different depth planes of the coating layer, it can be found that the surface of the coating layer contains MgCO3, MgO, Mg(OH)2, metallic Mg, metallic Zn and some complex zinc compounds. Under the surface, there is a Zn2Mg alloy layer with the thickness of about 300 nm accompanied with MgO and Mg(OH)2 in the layer. There is a transitional layer with the thickness of about 200 nm between the Zn2Mg alloy layer and the pure Zn layer, whose components consist of zinc-magnesium alloy without fixed stoichiometry, a little MgO and a little Mg(OH)2.

  1. Study of the sensitisation of a highly alloyed austenitic stainless steel, Alloy 926 (UNS N08926), by means of scanning electrochemical microscopy

    OpenAIRE

    Leiva García, Rafael; Akid, R.; Greenfield, D.; Gittens, J.; Muñoz Portero, María José; García Antón, José

    2012-01-01

    The feedback mode of a scanning electrochemical microscope (SECM) was applied to study differences in the reactivity of a highly alloyed austenitic stainless steel, Alloy 926 (UNS N08926), in its unsensitised and sensitised state. Alloy 926 was heated at 825 °C for 1 h in an inert atmosphere in order to produce a sensitised metallurgical condition. Sensitisation was due to chromium carbide formation at the grain boundaries. The oxygen reduction reaction was used as an indicator to monitor the...

  2. Lean-alloyed austenitic stainless steel with high resistance against hydrogen environment embrittlement

    International Nuclear Information System (INIS)

    Highlights: · Hydrogen environment embrittlement of austenitic steel. · Novel alloying concept for austenitic stainless steel with improved HEE resistance. · Influence of austenite stability and strain-induced α-martensite on HEE. · Cost efficiency by reduced amounts of nickel and molybdenum. · Influence of silicon on HEE. - Abstract: To address the upcoming austenitic stainless steel market for automotive applications involving hydrogen technology, a novel lean - alloyed material was developed and characterized. It comprises lower contents of nickel and molybdenum compared to existing steels for high - pressure hydrogen uses, for instance 1.4435 (AISI 316L). Alloying with manganese and carbon ensures a sufficient stability of the austenite at 8 wt.% of nickel while silicon is added to improve resistance against embrittlement by dissolved hydrogen. Investigations were performed by tensile testing in air and 400 bar hydrogen at 25 deg. C, respectively. In comparison to a standard 1.4307 (AISI 304L) material, a significant improvement of ductility was found. The materials concept is presented in general and discussed with regard to austenite stability and microstructure.

  3. Electrochemical characterization of oxide formed on chromium containing mild steel alloys in LiOH medium

    International Nuclear Information System (INIS)

    Flow accelerated corrosion leads to wall thinning of outlet-feeder pipes in the primary heat transport system of pressurized heavy water reactors and can even necessitate enmasse feeder replacement. Replacement of carbon steel 106-grade-B (CS) with chromium containing carbon steel reduces the risk of this failure. This paper discusses the role of small additions of chromium in modifying the properties of the oxide film. CS and chromium containing mild steels viz., A333, 2.25Cr–1Mo and modified 9Cr–1Mo alloy were exposed to primary heat transport (PHT) system chemistry conditions. The oxide films formed were characterized by electrochemical and surface characterization techniques. Mott–Schottky analysis showed donor type of defects. The densities of defects in the oxides of chromium containing alloys were 3–15 times less than that in CS. In presence of ∼200 ppb of dissolved oxygen, the oxides formed were hematite with two orders of magnitude smaller concentration of defects as compared to that formed under reducing conditions. These results suggest that the presence of chromium lowers the defect density of the oxide film and thus ensures a reduced corrosion rate. - Graphical abstract: Display Omitted - Highlights: • High temperature oxides formed on Cr containing mild steels are less defective. • Defect densities of oxides decrease with increase in Cr content in the alloy. • O2 in solution greatly influences the nature and defect chemistry of oxides

  4. Evaluation of interfacial microstructures in dissimilar joints of aluminum alloys to steel using nanoindentation technique

    International Nuclear Information System (INIS)

    The characteristics of interfacial microstructures with additional elements in dissimilar 6000 system aluminum/steel joints were basically evaluated using tensile test, EPMA, TEM and nanoindentation. For Si (and Cu)-added alloy (S1 and SC), EPMA analysis showed that Si (and Cu) was enrichment in the reaction layers, which were formed during diffusion bonding. SAED pattern clarified that the reaction compounds at the interface changed from AlFe intermetalic compounds to AlFeSi intermetalic compounds by Si addition. Nanoindentation technique was successfully applied to the interfacial microstructures to understand directly the nanoscopic mechanical properties in the interfacial microstructures. The hardness and Young's modulus of Al3Fe intermetalic compounds was lower than those of Al2Fe5 intermetalic compounds. Moreover, the hardness and Young's modulus of AlFeSi(Cu) compounds were lower than those of Al3Fe, indicating that the crystal system changed from orthorhombic structure to cubic structure. Joint strength of SC/steel joints was higher than that of the aluminum alloy with no additional element (Base)/ steel joint, indicating that interfacial microstructure was modified by the addition of Si and Cu to the 6000 system aluminum alloy. These results suggest that the nanoscopic mechanical properties at the interface microstructures affect greatly the macroscopic deformation behavior of the aluminum /steel dissimilar joints.

  5. Influence of silicon addition on the mechanical properties and corrosion resistance of low-alloy steel

    Indian Academy of Sciences (India)

    M Hebda; H Dębecka; J Kazior

    2015-12-01

    The addition of silicon to low-alloy steel allows to modify the materials' microstructure and thus to improve their corrosion resistance and mechanical properties. The influence of adding different amounts of silicon on the properties (density, transverse rupture strength, microhardness and corrosion resistance) and microstructure of low-alloy steel was investigated. Samples were prepared via the mechanical alloying process, which is the most useful method to homogeneously introduce silicon to low-alloy steel. Sintering was performed by using the spark plasma sintering (SPS) technique. After the SPS process, half of each of the obtained samples was heat-treated in a vacuum furnace. The results show that high-density materials were achieved, and a homogeneous and fine microstructure was obtained. The investigated compositions containing 1 wt% of silicon had better corrosion resistance than samples with 3 wt% of silicon addition. Furthermore, corrosion resistance as well as the mechanical and plastic properties of the samples with 1 wt% of silicon can be further improved by applying heat treatment.

  6. Influence of microstructure and environment on the fatigue behaviour of duplex stainless steels alloyed with nitrogen

    International Nuclear Information System (INIS)

    The favourable effect of nitrogen on the mechanical properties and the resistance to corrosion, now recognised for the austenitic stainless steels, aroused the interest for the development of dual - phase stainless steels constituted by austenite and ferrite (also labelled duplex steels) with high nitrogen content of which the interest lies in the lowest quantities of expensive alloying elements. The main purpose of this work is the study of the low cycle fatigue (LCF) behaviour of new grades of duplex steels and the determination of the microstructural scale conferring the best properties. LCF tests carried out in air on two duplex steels, with 0.24 wt% and 0.4 wt% of nitrogen and phase proportions of 50%α/50%γ and 30%α/70%γ respectively, led to the conclusion of a dependence of materials behaviour as a function of the strain level. The observations of samples by scanning electron microscopy showed that, for the lowest amplitudes, the plastic deformation is essentially accommodate by the austenite. Beyond a certain deformation, both phases alternatively accommodate this plastic deformation. In the presence of corrosive media, a general decrease of material fatigue lives has been noticed, except for the 0.4 wt% nitrogen containing steel which is less sensible. In the same way, an ageing treatment at 475 C for 200 hours lowers considerably the fatigue lives of the 0.24 wt% nitrogen steel while the resistance of the 0.4% nitrogen alloy is nearly unchanged. Whatever the conditions, the reductions of fatigue lives were systematically attributed to the ferritic phase behaviour. Then, elaborating these grades of duplex steels with 0.4 wt% of nitrogen favours a structure with 70% of austenite and leads to a very interesting fatigue behaviour. (O.M.)

  7. Neutron irradiation creep experiments on austenitic stainless steel alloys

    International Nuclear Information System (INIS)

    Results of measurements of the neutron induced creep elongation on AMCR-steels (Mn-base), on 316 CE-reference steels, and on US 316 jand US PCA steels are reported. It was found that the stationary creep rate is not very sensitive to variations of the irradiation temperature between 300 and 400 degC and that the stress-exponent of plastically deformed and of annealed materials is n ≅ and n ≅ 1.59, respectively. A small primary creep stage is found in annealed materials. Deformed materials show a negative creep elongation at the beginning of the irradiation, which increases for decreasing stresses and decreases for increasing irradiation temperatures. (author). 7 refs.; 7 figs.; 1 tab

  8. Structure and properties of surface layers obtained by alloying of the hot work tool steels

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2006-04-01

    Full Text Available Purpose: The aim of the present work was to study the microstructure and properties produced after laser alloying of the 55NiCrMoV7 and X40CrMoV5-1 an alloy hot-work tool steels.Design/methodology/approach: Structure investigation was performed using the light microscope Leica MEF4A supplied by Zeiss. Phase composition and crystallographic structure were determined by the X-ray diffraction method using the DRON 2.0. The measurements of microhardness have been performed using Shimadzu microhardness intender equipped with electronic sensor that allows the direct readout of the hardness values.Findings: The metallographic investigations on light microscope show that steel after laser remelting can be characterized by a dendrite structure. Metallographic examinations on the scanning microscope with the EDX attachment confirm the occurrence of the niobium carbides in the surface layer of the investigated steels.Research limitations/implications: In order to evaluate with more detail the possibility of applying these surface layers in tools, further investigations should be concentrated on the determination of the thermal fatigue resistance of the layers.Practical implications: The surface layer of the hot work steel alloyed with ceramic powder have good properties and make possibility for uses it in various technical and industrial applications.Originality/value: The microstructure and properties of the surface layer of the 55NiCrMoV7 and X40CrMoV5-1 hot-work tool steels alloying with ceramic powder were compared.

  9. Corrosion of ferritic-martensitic steels and nickel-based alloys in supercritical water

    Science.gov (United States)

    Ren, Xiaowei

    The corrosion behavior of ferritic/martensitic (F/M) steels and Ni-based alloys in supercritical water (SCW) has been studied due to their potential applications in future nuclear reactor systems, fossil fuel power plants and waste treatment processes. 9˜12% chromium ferritic/martensitic steels exhibit good radiation resistance and stress corrosion cracking resistance. Ni-based alloys with an austenitic face-centered cubic (FCC) structure are designed to retain good mechanical strength and corrosion/oxidation resistance at elevated temperatures. Corrosion tests were carried out at three temperatures, 360°C, 500°C and 600°C, with two dissolved oxygen contents, 25 ppb and 2 ppm for up to 3000 hours. Alloys modified by grain refinement and reactive element addition were also investigated to determine their ability to improve the corrosion resistance in SCW. A duplex oxide structure was observed in the F/M steels after exposure to 25 ppb oxygen SCW, including an outer oxide layer with columnar magnetite grains and an inner oxide layer constituted of a mixture of spinel and ferrite phases in an equiaxed grain structure. An additional outermost hematite layer formed in the SCW-exposed samples when the oxygen content was increased to 2 ppm. Weight gain in the F/M steels increased with exposure temperatures and times, and followed parabolic growth kinetics in most of the samples. In Ni-based alloys after exposure to SCW, general corrosion and pitting corrosion were observed, and intergranular corrosion was found when exposed at 600°C due to formation of a local healing layer. The general oxide structure on the Ni-based alloys was characterized as NiO/Spinel/(CrxFe 1-x)2O3/(Fe,Ni). No change in oxidation mechanism was observed in crossing the critical point despite the large change in water properties. Corrosion resistance of the F/M steels was significantly improved by plasma-based yttrium surface treatment because of restrained outward diffusion of iron by the

  10. Reducing the content of alloying elements in high-speed steel during heating in salt baths

    International Nuclear Information System (INIS)

    Barium chloride salt baths are primarily used for the high-temperature quench heating of a tool formed from high-speed steels. If the barium chloride melt should have a decarbonizing effect on the surface components that are heated in it, the authors maintain that it may also affect the content of alloying elements in the surface layers of high-speed-steel components that are heated in it. Commercial salt baths with a rectifier -- chemically pure magnesium fluoride -was used for the investigation. Cooling was accomplished in a caustic melt. Analysis of the results of investigation of the molybdenum, tungsten, and cobalt distributions in steel R9M4K8 as well as the tungsten and cobalt distributions in steel R9K5 indicated that the cobalt content does not diminish on heating to 12300C. A decrease in molybdenum content occurs in the surface layers during the quench heating of a tool formed from high-speed tungsten-molybdenum steel in a barium chloride salt bath after the required heating time, while a decrease in the tungsten content takes place with more prolonged hold times. It is shown to be possible to reduce or completely eliminate loss of alloying elements in the surface layers of a high-speedsteel tool during heat treatment when magnesium fluoride in combination with silicon carbide additives is used as a rectifier

  11. The influence of nitrogen alloying on the pitting and crevice corrosion of austenitic and duplex stainless steels

    International Nuclear Information System (INIS)

    The effect of nitrogen alloying on the pitting corrosion resistance of duplex and austenitic stainless steels has been examined. In order to avoid alteration of the phase ratio as a result of nitrogen alloying of the duplex steels, a simultaneous decrease has been made in the nickel content. Austenitic alloys of compositions corresponding to the austenite phase of the duplex steels have been investigated and compared to the behaviour of austenitic steels in which the nitrogen content or the nickel content alone has been varied. Nitrogen has a beneficial effect on pitting and crevice corrosion resistance in all cases but the duplex stainless steel exhibit a lower resistance to pitting and a higher resistance to crevice corrosion than predicted from the austenite nitrogen content. (orig.)

  12. Mechanical and Electrochemical Behavior of a High Strength Low Alloy Steel of Different Grain Sizes

    Science.gov (United States)

    Ghosh, K. S.; Mondal, D. K.

    2013-08-01

    Various heat treatments applied to a fine-grained high strength low alloy (HSLA) steel resulted in producing different grain sizes. Optical and scanning electron microstructures of the different alloy states exhibited varying ferrite grains which have increased with the increase of annealing time and decrease of cooling rates. TEM structures of the as-received HSLA steel displayed characteristics microstructural features, distribution, and morphology of microalloy precipitates. Hardness and tensile strength values have decreased with the increase of grain sizes. Potentiodynamic electrochemical polarization of the different alloy states in 3.5 wt pct NaCl solution showed typical active metal/alloy behavior. Tensile specimens of the as-received and heat-treated alloy cathodically charged with hydrogen, followed by tensile testing, did not indicate any noticeable loss of ductility. FESEM fractographs of hydrogen-charged samples showed a few chain of voids in the presence of cup and cone ductile fracture features in tensile-tested samples without hydrogen charging as well.

  13. Structure and properties of hotwork tool steel alloyed by WC carbides by a use of high power diode laser

    OpenAIRE

    M. Bonek; L.A. Dobrzański; Klimpel, A

    2007-01-01

    Purpose: The paper presents the effect of alloying with tungsten carbide on properties of the X40CrMoV5-1 steel surface layer, using the high power diode laser (HPDL).Design/methodology/approach: The structural mechanism of surface layer development was determined and the effect of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer was studi...

  14. Quantitative consideration for the tempering effect during multi-pass thermal cycle in HAZ of low-alloy steel

    International Nuclear Information System (INIS)

    A new Thermal Cycle Tempering Parameter (TCTP) to deal with the tempering effect during multi-pass thermal cycles has been proposed by extending Larson-Miller parameter (LMP). Experimental result revealed that the hardness in synthetic HAZ of the low alloy steel subjected to multi tempering thermal cycles has a good linear relationship with TCTP. By using this relationship, the hardness of the low-alloy steel reheated with tempering thermal cycles can be predicted when the original hardness is known. (author)

  15. BORATING OF CARBON AND ALLOY STEEL IN BOILING LAYER

    Directory of Open Access Journals (Sweden)

    N. Koukhareva

    2012-01-01

    Full Text Available The paper describes how to obtain boride coatings on steel 20, 4X5MФС, X12M being treated in a boiling layer of metallothermic powder environment. Phase and chemical compositions, hardness and wear- resistance of boride coatings

  16. FERRITE STRUCTURE AND MECHANICAL PROPERTIES OF LOW ALLOY DUPLEX STEELS

    Energy Technology Data Exchange (ETDEWEB)

    Hoel, R.H.; Thomas, G.

    1981-04-01

    The purpose of this communication is threefold. 1) To confirm the presence of and to characterize the precipitates in the ferrite phase of the base + Nb and base + Mo steels, 2) to study any possible variation in precipitate density as the martensitic volume fraction is changed and 3) to determine the level of precipitation strengthening.

  17. Advances in development of refractory austenitic steels and nickel alloys for power engineering

    International Nuclear Information System (INIS)

    An evaluation is presented of the current state of knowledge of the properties and technologies of refractory austenitic steels and Ni alloys, this mainly of materials used in the temperature range of 600 to 1100 degC where the main causes of damage are creep, fatigue and high temperature corrosion. Attention is mainly devoted to the results of applied research. The problems of concrete applications in nuclear engineering were dealt with in the paper ''Assessment of long-term refractory properties of selected types of austenitic steels''. (J.B.)

  18. Effect of plasma nitrided layers on low- alloy steel on its hydrogen degradation

    OpenAIRE

    A. Zieliński; J. Ćwiek; B. Błaszkiewicz

    2006-01-01

    Purpose: Purpose of this paper is evaluation of susceptibility to hydrogen degradation of structural low-alloy steel, plasma nitrided in the atmosphere with various contents of N2 and H2.Design/methodology/approach: Susceptibility of 34CrAlNi7-10 steel and samples with various plasma nitrided layers have been evaluated under monotonically increasing load in 0.005 M H2SO4 solution. Slow-strain rate tensile test (SSRT) test was carried out under cathodic polarisation. Elongation, reduction in a...

  19. Assessment of the Low Alloy Cast Steel Inoculation Effects with Chosen Additives

    Directory of Open Access Journals (Sweden)

    D. Bartocha

    2012-04-01

    Full Text Available Structure, and thus the mechanical properties of steel are primarily a function of chemical composition and the solidification process which can be influenced by the application of the inoculation treatment. This effect depends on the modifier used. The article presents the results of studies designed to assess the effects of structural low alloy steel inoculation by selected modifying additives. The study was performed on nine casts modeled with different inoculants, assessment of the procedure impact was based on the macrostructure of made castings. The ratio of surface area equivalent to the axial zone of the crystals and columnar crystals zone was adopted as a measure of the inoculation effect.

  20. Dynamic Recrystallization and Grain Growth Behavior of 20SiMn Low Carbon Alloy Steel

    Institute of Scientific and Technical Information of China (English)

    DONG Lanfeng; ZHONG Yuexian; MA Qingxian; YUAN Chaolong; MA Lishen

    2008-01-01

    A senes of thermodynamics experiments were used to optimize the hot forging process of 20SiMn low-carbon alloy steel.A dynamic recrystallization and grain growth model was developed for the 20SiMn steel for common production conditions of heavy forgings by doing a nonlinear curve fit of the expenment data.Optimized forging parameters were developed based on the control of the dynamic recrystallization and the MnS secondary phase.The data shows that the initial grain size and the MnS secondary phase all affect the behavior of the 20SiMn dynamic recrystallization and grain growth.

  1. Cold weld cracking susceptibility of high strength low alloyed (HSLA steel NIONIKRAL 70

    Directory of Open Access Journals (Sweden)

    A. S. Tawengi

    2014-10-01

    Full Text Available In view of the importance of high strength low alloy (HSLA steels, particularly for critical applications such as offshore plat forms, pipeline and pressure vessels, this paper reports on an investigation of how to weld this type of steel without cold cracking. Using manual metal arc welding process and Tekken test (Y - Grove test has been carried out both to observe the cold cracking phenome non, and to investigate the influencing factors, such as preheating temperature and energy input, as well as electrode strength and diameter. How ever the results of the experiments show that there is a risk of cold cracking.

  2. Effect of Nitriding on Fatigue Characteristics of Cr-Mo Alloy Steel

    International Nuclear Information System (INIS)

    CrMo alloy steel was nitrided using two types of processing methods, ion-nitriding processing and nitrocarburizing. Both processes were conducted for a duration of 30 min. To compare the surface hardness of the alloys created by the different processes , microhardness tests were conducted, and fatigue tests of each material were performed by a cantilever rotary bending fatigue test machine (Yamamoto, YRB 200) in the very high cycle regime (N > 107cycle). Fractography of the fractured surfaces was conducted by scanning electron microscopy - to observe the fracture mechanisms of very high cycle fatigue and the effect of the nitriding process on the fatigue characteristics

  3. Effect of Nitriding on Fatigue Characteristics of Cr-Mo Alloy Steel

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Kwang Keun; Kim, Jae Hoon; Choi, Hoon Seok [Chungnam National University, Daejeon (Korea, Republic of)

    2015-06-15

    CrMo alloy steel was nitrided using two types of processing methods, ion-nitriding processing and nitrocarburizing. Both processes were conducted for a duration of 30 min. To compare the surface hardness of the alloys created by the different processes , microhardness tests were conducted, and fatigue tests of each material were performed by a cantilever rotary bending fatigue test machine (Yamamoto, YRB 200) in the very high cycle regime (N > 10{sup 7}cycle). Fractography of the fractured surfaces was conducted by scanning electron microscopy - to observe the fracture mechanisms of very high cycle fatigue and the effect of the nitriding process on the fatigue characteristics.

  4. Structure and properties of surface layers obtained by alloying of the hot work tool steels

    OpenAIRE

    L.A. Dobrzański; A. Polok; E. Jonda

    2006-01-01

    Purpose: The aim of the present work was to study the microstructure and properties produced after laser alloying of the 55NiCrMoV7 and X40CrMoV5-1 an alloy hot-work tool steels.Design/methodology/approach: Structure investigation was performed using the light microscope Leica MEF4A supplied by Zeiss. Phase composition and crystallographic structure were determined by the X-ray diffraction method using the DRON 2.0. The measurements of microhardness have been performed using Shimadzu microhar...

  5. Effects of alloy and solution chemistry on the fracture of passive films on austenitic stainless steel

    International Nuclear Information System (INIS)

    The Taguchi analysis method was used to simultaneously study the effects of alloy chemistry, pH, and halide ion concentrations on the fracture of electrochemically grown passive films using a nanoindentation technique. Three austenitic stainless steels, 304L, 316L, and 904L were potentiostatically polarized in hydrochloric acid solutions. The fracture load was dominated primarily by alloy chemistry. Passive films mechanically weaken as the atomic iron concentration increases in the film. Prolonged anodic ageing time increases the fracture load of passive films

  6. Effects of alloy and solution chemistry on the fracture of passive films on austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Alamr, A. [School of Mechanical and Materials Engineering, Washington State University, P.O. Box 642920, Pullman, WA 99164-2920 (United States)]. E-mail: alamrz@wsu.edu; Bahr, D.F. [School of Mechanical and Materials Engineering, Washington State University, P.O. Box 642920, Pullman, WA 99164-2920 (United States)]. E-mail: bahr@mail.wsu.edu; Jacroux, Michael [Department of Statistics, Washington State University, Pullman, WA 99164-3144 (United States) ]. E-mail: jacroux@wsu.edu

    2006-04-15

    The Taguchi analysis method was used to simultaneously study the effects of alloy chemistry, pH, and halide ion concentrations on the fracture of electrochemically grown passive films using a nanoindentation technique. Three austenitic stainless steels, 304L, 316L, and 904L were potentiostatically polarized in hydrochloric acid solutions. The fracture load was dominated primarily by alloy chemistry. Passive films mechanically weaken as the atomic iron concentration increases in the film. Prolonged anodic ageing time increases the fracture load of passive films.

  7. A thermostatistical theory for solid solution effects in the hot deformation of alloys: an application to low-alloy steels

    International Nuclear Information System (INIS)

    The hot deformation of low-alloy steels is described by a thermostatistical theory of plastic deformation. This is based on defining a statistical entropy term that accounts for the energy dissipation due to possible dislocation displacements. In this case, dilute substitutional and interstitial atom effects alter such paths. The dislocation population is described by a single parameter equation, with the parameter being the average dislocation density. Solute effects incorporate additional dislocation generation sources. They alter the energy barriers corresponding to the activation energies for dislocation recovery, grain nucleation and growth. The model is employed to describe work hardening and dynamic recrystallization softening in fifteen steels for a wide range of compositions, temperatures and strain rates. Maps for dynamic recrystallization occurrence are defined in terms of processing conditions and composition. (paper)

  8. Influence of additional alloying with nitrogen on structure and properties of high chromium steel Kh17 after hot rolling

    International Nuclear Information System (INIS)

    A study was made into the structure and mechanical properties of steel Kh17 with 0.16% N after hot rolling under various conditions. It is shown that nitrogen alloying promotes steel transition into a two-phase state (α+γ) in heating above 850 deg C and affects mechanical properties of the steel in a hot rolled state. Impact strength is at its maximum in nitrogen containing steel kh17 if the rolling is in the temperature range of α-phase solid solution. Depending on the temperatures of hot rolling beginning and completion the distinctions in steel microstructure are investigated

  9. Mechanical properties and microstructure of copper alloys and copper alloy-stainless steel laminates for fusion reactor high heat flux applications

    Science.gov (United States)

    Leedy, Kevin Daniel

    A select group of copper alloys and bonded copper alloy-stainless steel panels are under consideration for heat sink applications in first wall and divertor structures of a planned thermonuclear fusion reactor. Because these materials must retain high strengths and withstand high heat fluxes, their material properties and microstructures must be well understood. Candidate copper alloys include precipitate strengthened CuNiBe and CuCrZr and dispersion strengthened Cu-Alsb2Osb3 (CuAl25). In this study, uniaxial mechanical fatigue tests were conducted on bulk copper alloy materials at temperatures up to 500sp°C in air and vacuum environments. Based on standardized mechanical properties measurement techniques, a series of tests were also implemented to characterize copper alloy-316L stainless steel joints produced by hot isostatic pressing or by explosive bonding. The correlation between mechanical properties and the microstructure of fatigued copper alloys and the interface of copper alloy-stainless steel laminates was examined. Commercial grades of these alloys were used to maintain a degree of standardization in the materials testing. The commercial alloys used were OMG Americas Glidcop CuAl25 and CuAl15; Brush Wellman Hycon 3HP and Trefimetaux CuNiBe; and Kabelmetal Elbrodur and Trefimetaux CuCrZr. CuAl25 and CuNiBe alloys possessed the best combination of fatigue resistance and microstructural stability. The CuAl25 alloy showed only minimal microstructural changes following fatigue while the CuNiBe alloy consistently exhibited the highest fatigue strength. Transmission electron microscopy observations revealed that small matrix grain sizes and high densities of submicron strengthening phases promoted homogeneous slip deformation in the copper alloys. Thus, highly organized fatigue dislocation structure formation, as commonly found in oxygen-free high conductivity Cu, was inhibited. A solid plate of CuAl25 alloy hot isostatically pressed to a 316L stainless steel

  10. Laser surface alloying of carbon steel and α-Fe with CrB2 particles

    International Nuclear Information System (INIS)

    A continuous wave, 2.5kW CO2 laser was used to surface alloy AISI 1045 steel and α-Fe with CrB2 by the powder injection method. CrB2 particles (100-150μ size) were injected into the molten bath of the substrate. The particles were partially dissolved in the bath, forming a melted layer of Fe-Cr-B-C. The solidification resulted in the formation of iron borides and undissolved CrB2 in the case of Armco iron and additional α-ferrite, γ-austenite and chromium carbides in the SAE 1045 steel. The hardness was high, 1250 HV in both cases, caused mainly by the borides. The overlap of the laser passes did not affect the hardness distribution throughout the alloyed layer. The structure and properties of the layers were studied using X-ray diffraction, Auger electron spectroscopy, scanning electron microscopy and optical microscopy. (orig.)

  11. Characterization of atom clusters in irradiated pressure vessel steels and model alloys

    International Nuclear Information System (INIS)

    In order to characterize the microstructural evolution of the iron solid solution under irradiation, two pressure vessel steels irradiated in service conditions and, for comparison, low copper model alloys irradiated with neutrons and electrons have been studied. The characterization has been carried out mainly thanks to small angle neutron scattering and atom probe experiments. Both techniques lead to the conclusion that clusters develop with irradiations. In Fe-Cu model alloys, copper clusters are formed containing uncertain proportions of iron. In the low copper industrial steels, the feature is more complex. Solute atoms like Ni, Mn and Si, sometimes associated with Cu, segregate as ''clouds'' more or less condensed in the iron solid solution. These silicides, or at least Si, Ni, Mn association, may facilitate the copper segregation although the initial iron matrix contains a low copper concentration. (authors). 24 refs., 3 figs., 2 tabs

  12. Literature Survey on the Stress Corrosion Cracking of Low-Alloy Steels in High Temperature Water

    International Nuclear Information System (INIS)

    The present report is a summary of a literature survey on the stress corrosion cracking (SCC) behaviour/ mechanisms in low-alloy steels (LAS) in high-temperature water with special emphasis to primary-pressure-boundary components of boiling water reactors (BWR). A brief overview on the current state of knowledge concerning SCC of low-alloy reactor pressure vessel and piping steels under BWR conditions is given. After a short introduction on general aspects of SCC, the main influence parameter and available quantitative literature data concerning SCC of LAS in high-temperature water are discussed on a phenomenological basis followed by a summary of the most popular SCC models for this corrosion system. The BWR operating experience and service cracking incidents are discussed with respect to the existing laboratory data and background knowledge. Finally, the most important open questions and topics for further experimental investigations are outlined. (author)

  13. Influence of Boron on transformation behavior during continuous cooling of low alloyed steels

    Energy Technology Data Exchange (ETDEWEB)

    Terzic, A., E-mail: Adnan.Terzic@imf.tu-freiberg.de [Technische Universität Bergakademie Freiberg, Institute of Metal Forming, Bernhard-von-Cotta-Str. 4, 09596 Freiberg (Germany); Calcagnotto, M. [Salzgitter Mannesmann Forschung GmbH, Eisenhüttenstr. 99, 38239 Salzgitter (Germany); Guk, S. [Technische Universität Bergakademie Freiberg, Institute of Metal Forming, Bernhard-von-Cotta-Str. 4, 09596 Freiberg (Germany); Schulz, T. [Salzgitter Mannesmann Forschung GmbH, Eisenhüttenstr. 99, 38239 Salzgitter (Germany); Kawalla, R. [Technische Universität Bergakademie Freiberg, Institute of Metal Forming, Bernhard-von-Cotta-Str. 4, 09596 Freiberg (Germany)

    2013-11-01

    Abstracts: The phase transformation behavior during continuous cooling of low-carbon (LC) Boron-treated steels was studied. Furthermore, the influence of combining Boron with Nb or Ti or V on transformation kinetics was investigated. Additions of Boron to LC steels have a strong influence on the ferrite transformation. By adding 30 ppm Boron to a Boron-free reference alloy the suppressing effect on the ferrite transformation is most pronounced, whereas 10 ppm Boron has almost no effect and 50 ppm Boron the same effect as 30 ppm Boron. Thereby the critical Boron concentration for transformation kinetics in this alloying concept is 30 ppm. The combination of Boron with Ti shifts the phase fields to shorter times and increase the ferrite start temperature, whereas the combination of B+V and B+Nb only affects the ferrite start temperature. Hardness values are mostly influenced by the presence of Boron and strongly depend on the cooling rate.

  14. Oxidation and corrosion behavior of modified-composition, low-chromium 304 stainless steel alloys

    International Nuclear Information System (INIS)

    The effects of substituting less strategic elements than Cr on the oxidation and corrosion resistance of AISI 304 stainless steel were investigated. Cyclic oxidation resistance was evaluated at 870 C. Corrosion resistance was determined by exposure of specimens to a boiling copper-rich solution of copper sulfate and sulfuric acid. Alloy substitutes for Cr included Al, Mn, Mo, Si, Ti, V, Y, and misch metal. A level of about 12% Cr was the minimum amount of Cr required for adequate oxidation and corrosion resistance in the modified composition 304 stainless steels. This represents a Cr saving of at least 33%. Two alloys containing 12% Cr and 2% Al plus 2% Mo and 12% Cr plus 2.65% Si were identified as most promising for more detailed evaluation

  15. Mechanical and Microstructural Properties of Low Alloy-Treated Steel Used in Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    F. Niang

    2012-03-01

    Full Text Available The aim of this communication is a comparative study of various types of reinforcements made of mild steel used in reinforced concretes in Senegal and Benin, in order to evaluate their standards. This benchmarking is based on the study of the mechanical and microstructural properties of the various selected products. The results obtained show that the ferrous alloys, used as reinforcing bars in Senegal and Benin, do not respect the performance criteria recommended in the building sector (standard NF has 35-016. In fact, the yield point, the elongation at rupture as well as the geometrical tolerances remain overall lower than the recommended values. The conclusions proposed prospects for heat treatments that should ensure optimization of the properties of the low alloy-treated steel used in the building sector.

  16. Literature Survey on the Stress Corrosion Cracking of Low-Alloy Steels in High Temperature Water

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, H.P

    2002-02-01

    The present report is a summary of a literature survey on the stress corrosion cracking (SCC) behaviour/ mechanisms in low-alloy steels (LAS) in high-temperature water with special emphasis to primary-pressure-boundary components of boiling water reactors (BWR). A brief overview on the current state of knowledge concerning SCC of low-alloy reactor pressure vessel and piping steels under BWR conditions is given. After a short introduction on general aspects of SCC, the main influence parameter and available quantitative literature data concerning SCC of LAS in high-temperature water are discussed on a phenomenological basis followed by a summary of the most popular SCC models for this corrosion system. The BWR operating experience and service cracking incidents are discussed with respect to the existing laboratory data and background knowledge. Finally, the most important open questions and topics for further experimental investigations are outlined. (author)

  17. Application and trend of development of steel and alloy for nuclear power plant

    International Nuclear Information System (INIS)

    The development of nuclear power plant (NPP) is for electricity production now in the long stagnation time after the Chernobyl accident. New developments are mostly based on smaller reactor designs, with less dependence on safety-protection system, lower capital cost, and short construction times. One route is through a new advanced pressurizer-water reactor (APWR) and advanced boiling-water reactor (ABWR) designs that are based on the existing systems. A more radical and exciting prospects is a South African-led pebble bed modular reactor (PMBR) design, based on the high temperature reactor concept as developed in Germany. Such new designs need also a new material for the calculation of the concept. In this paper, present steels and alloys at the NPP and future trend of material and the prospects of the advanced material and the possibility steel and alloy research for NPP in BATAN

  18. Research on CMT welding of nickel-based alloy with stainless steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Cold Metal Transfer (CMT) welding technique is a new welding technique introduced by Fronius company. CMT welding of nickel-based alloy with stainless steel was carried out using CuSi3 filler wire in this paper. Effects of welding parameters, including welding current, welding speed, etc, on weld surface appearance were tested. Microstructure and mechanical properties of CMT weld were studied. The results show that the thickness of interface reaction layer of the nickel-based alloy is 14.3μm, which is only 4.33% of base material. The weld is made up of two phases,α-copper and iron-based solid solution. Rupture occurs initially at the welded seam near the edge of stainless steel in shear test. The maximum shear strength of the CuSi3 welded joint is 184.9MPa.

  19. Effect Mo Addition on Corrosion Property and Sulfide Stress Cracking Susceptibility of High Strength Low Alloy Steels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woo Yong; Koh, Seong Ung; Kim, Kyoo Young [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2005-04-15

    The purpose of this work is to understand the effect of Mo addition on SSC susceptibility of high strength low alloy steels in terms of microstructure and corrosion property. Materials used in this study are high strength low alloy (HSLA) steels with carbon content of 0.04wt% and Mo content varying from 0.1 to 0.3wt%. The corrosion property of steels was evaluated by immersion test in NACE-TM01-77 solution A and by analyzing the growth behavior of surface corrosion products. SSC resistance of steels was evaluated using constant load test. Electrochemical test was performed to investigate initial corrosion rate. Addition of Mo increased corrosion rate of steels by enhancing the porosity of surface corrosion products. however, corrosion rate was not directly related to SSC susceptibility of steels

  20. 77 FR 43806 - Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's Republic of...

    Science.gov (United States)

    2012-07-26

    ... International Trade Administration Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the... Administrative Reviews and Request for Revocation in Part, 76 FR 82268 (December 30, 2011). The review covers 32... Charging Development Co., Ltd.; Wuxi Resources Steel Making Co., Ltd.; Wuxi Seamless Special Pipe Co.,...

  1. The influence of chemical constitution on abrasive wear of alloy cast steel Cr, Mo, V, Cu, Ni type

    International Nuclear Information System (INIS)

    In the work were presented some elements of a wide research programme of the influence of alloying element contents such as Cr, Mo, V on the abrasive wear of hot working cast steel. The dependence between the mass decrement quantity and the element contents on cast steel structure were shown. (author)

  2. The diffusion of chromium in a duplex alloy steel

    International Nuclear Information System (INIS)

    Diffusion of chromium in a duplex stainless steel containing approximately 8% ferrite has been investigated in the temperature range 600 to 10000C using the standard serial sectioning technique. The resulting concentration profiles exhibited up to four distinct regions. The two main regions are attributed to volume diffusion in the austenite and ferrite phases, the other zones being due to short circuiting paths. Volume diffusion in the austenite phase is in good agreement with chromium diffusion in Type 316 steel. The chromium diffusion coefficient in the ferrite phase of approximate composition 25 wt % Cr, 5 wt % Ni is given by: Dsub(α) = (6.0(+11,-3)) x 10-6 exp - ((212+-5)/RT) m2s-1 the activation energy being expressed in kJ.mol-1. Little evidence was found for enhanced chromium diffusion along austenite/ferrite interface boundaries. (author)

  3. Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel

    Science.gov (United States)

    Wang, Jing; Lu, Min-xu; Zhang, Lei; Chang, Wei; Xu, Li-ning; Hu, Li-hua

    2012-06-01

    To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by energy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corrosion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG welding. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints produced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.

  4. Influence of alloying elements on the corrosion properties of shape memory stainless steels

    International Nuclear Information System (INIS)

    Highlights: ► The corrosion properties of three Fe–Mn–Si–Cr–Ni–(Co) shape-memory stainless steels (SMSSs) were compared with those of a type 304 (SS 304) austenitic stainless steel. ► A considerably high Si content (about 40 at%) is present in the anodic passive films formed on SMSSs in 0.5 M H2SO4 solution. ► The high protectiveness of the anodic passive film formed on SMSSs in 0.5 M H2SO4 solution results from a protective film consisting of a (Fe, Cr)–mixed silicate. ► The SMSSs exhibited higher corrosion resistance than SS 304 in highly oxidizing environments. ► The SMSSs showed poor corrosion resistance in 3.5% NaCl solution compared to that of SS 304. - Abstract: The corrosion properties of three Fe–Mn–Si–Cr–Ni–(Co) shape memory stainless steels were studied based on X-ray photoelectron spectroscopy (XPS) analyses, immersion and polarization tests. The test results were compared with those of a type 304 austenitic stainless steel. The XPS analyses indicated substantial Si content in the anodic passive films formed on shape memory stainless steels in sulfuric acid solution and that the high protectiveness of these films results from a protective film consisting of a (iron, chromium)–mixed silicate. The corrosion rate of the shape memory stainless steels in boiling nitric acid solution was lower than that of austenitic stainless steel. The high silicon content was found to play an important role in the corrosion behavior of these shape memory alloys in highly oxidizing environments. Due to their high manganese content, the shape memory stainless steels showed poor corrosion behavior in 3.5% sodium chloride solution when compared with austenitic stainless steel.

  5. SAW surfacing of low-alloyed steel with super-ferrite additional material

    OpenAIRE

    Klimpel, A; T. Kik; J. Górka; A. Czupryński; P. Sitarz

    2009-01-01

    Purpose: of these researches was to investigate influence of heat input in SAW surfacing of low-alloyed steel with super-ferrite filler material on quality of deposits.Design/methodology/approach: the quality of single and multilayer, stringer beads was assessed by metallographic examinations, stresses measurements and hardness tests.Findings: due to the fact that it was used at automated surfacing stand, the analysis of properties of the deposits was performed for single and multilayer, str...

  6. BEHAVIOUR OF COPPER AND ALUMINIUM ELECTRODES ON EDM OF EN-8 ALLOY STEEL

    OpenAIRE

    DHANANJAY PRADHAN; Dr. S. C. JAYSWAL

    2011-01-01

    Electrical discharge machining (EDM) has been recognized as an efficient production method for precision machining of electrically conducting hardened materials. Copper and aluminium are used as electrode materials in this process with Kerosene oil as the dielectric medium. In this work, the behavior of copper and aluminium electrodes on electric discharge machining of EN-8 alloy steel had been studied. Keeping all other machining parameters same, the hardened work material was machined with ...

  7. Low stacking fault energy steels in the context of manganese-rich iron-based alloys

    International Nuclear Information System (INIS)

    The role of stacking fault energy on defining the work-hardening behavior of manganese-rich iron-based alloys was highlighted by the tensile deformation of four high-manganese steels designed using thermodynamic mechanism maps. The flow behavior and work-hardening rate diagrams, together with the activity of different deformation mechanisms (deformation-induced martensitic transformations and deformation twinning), were evaluated in conjunction with the microstructural investigations using electron backscattering diffraction.

  8. Automated equipment for determining the magnetic susceptibility of steels and alloys

    Directory of Open Access Journals (Sweden)

    G. V. Snizhnoi

    2012-10-01

    Full Text Available Automated equipment for determining the susceptibility of steels and alloys proposed. The principle of operation of equipment units and their main characteristics are presented. Microprocessor system with AVR microcontrollers from ATMEL for equipment used. The algorithm of the program a microprocessor system for automatic operation of equipment considered. Dependence of the current compensation of the current force field as a text file on your computer equipment can be formed.

  9. Fracture toughness of welded joints of a high strength low alloy steel

    International Nuclear Information System (INIS)

    The fracture toughness of the different regions of welded joints of a high strength low alloy steel, Niocor 2, was evaluated at different temperatures and compared with the toughness of the base metal. The studied regions were: the weld metal, fusion boundary and heat affected zone. The welding process used was the manual metal arc. It is shown that the weld metal region has the highest toughness values. (Author)

  10. Development of welding consumables for wet underwater welding of high-alloy corrosion-resistant steel

    OpenAIRE

    Kakhovskyi, Yurij; Kakhovskyi, Mykola

    2015-01-01

    This paper discusses a technology of mechanized wet underwater welding of high-alloy corrosion-resistance steel. The main aim of the investigation is development of self-shielded flux-cored wire for wet underwater welding for the first time in the world practice. A mathematical method of experiment design was used for determination of quantity and quality characteristics. Besides, quantitive and qualitative indices of welding-technological characteristics such as weld metal gas saturation, st...

  11. Microstructure evolution during laser-aided direct metal deposition of alloy tool steel

    International Nuclear Information System (INIS)

    Laser-aided direct metal deposition has been used to form an alloy tool steel coating. The microstructure of the deposited material was analyzed by means of scanning electron microscopy and transmission electron microscopy. The formation relationships among martensite, ε-carbide, cementite and austenite in the coating are discussed. The effect of rapid solidification associated with direct metal deposition on lattice parameters is also reported.

  12. Investigations for assessing the proneness to dynamic strain ageing of low alloy steels

    International Nuclear Information System (INIS)

    Plastic deformation of four low-alloy steels (four basic materials and two welding materials) for pipeline construction was investigated with regard to the influence of dynamic strain ageing on the localisation of deformation. First, the materials were classified in terms of ageing resistance on the basis of mechanical materials tests. After this, plastic strain was induced in the materials, and local deformations were analyzed. The deformation process was analyzed in detail

  13. Theoretical calculation of the impact work in the alloying non-quenched and tempered steel

    Institute of Scientific and Technical Information of China (English)

    LIU; Zhilin; LIN; Cheng

    2006-01-01

    Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel, the calculations of the finishing rolling impact work in the alloying non-quenched and tempered steel with the elements of Cr, Ni, Mo, W, Cu, V, Nb and Ti are studied with the covalent electron number nA of the strongest bond in alloying phases, the smallest electron density difference △ρ of phase interfaces, and the number of atom states σ(σ') which keep the interface electron density continuous. The calculated results show that the finishing rolling impact work of the alloying non-quenched and tempered steel intensely depends on strengthening mechanisms. The solution strengthening, interface strengthening, precipitation strengthening of pearlite, and dispersion strengthening will result in the decrease of the finishing rolling impact work; the refinement strengthening, the precipitation strengthening of V, Nb and Ti in o-Fe-C-V(Nb, Ti), and the residual austenite containing Ni on the boundary of α-Fe-C-Ni will increase the impact work; and the increments or decrements can be calculated with nA, △ρ, σ(σ') and weights of alloying elements. The calculation formulas of the finishing rolling impact work in this paper are intergraded with the suggested ones of the finishing rolling tensile strength, yield strength, and elongation of the non-quenched and tempered steel. The calculated results agree well with the measured ones.

  14. Studies of oxide reduction and nitrogen uptake in sintering of chromium-alloyed steel powder

    OpenAIRE

    Bergman, Ola

    2008-01-01

    The powder metallurgy (PM) process route is very competitive for mass production of structural steel components with complex shape, due to efficient material utilisation, low energy consumption, and short overall production time. The most commonly used alloying elements are the processing friendly metals Cu, Ni and Mo. However, the prices for these metals are today high and volatile, which threatens to make the PM process less competitive compared to conventional metal forming processes. Cons...

  15. Hydrogen trapping in bearing steels: mechanisms and alloy design

    OpenAIRE

    Szost, Blanka Angelika

    2013-01-01

    Hydrogen embrittlement is a problem that offers challenges both to technology and to the theory of metallurgy. In the presence of a hydrogen rich environment, applications such as rolling bearings display a significant decrease in alloy strength and accelerated failure due to rolling contact fatigue. In spite of these problems being well recognised, there is little understanding as to which mechanisms are present in hydrogen induced bearing failure. The objective of this thesis are twofold...

  16. Mechanical and tribological properties of the surface layer of the hot work tool steel obtained by laser alloying

    OpenAIRE

    K. Lukaszkowicz; A. Kriz; E. Jonda; L.A. Dobrzański

    2007-01-01

    Purpose: The paper presents results on the mechanical and tribological properties examinations of the X40CRMoV5-1 hot work alloy tool steel alloyed with carbide powders using the high power diode laser (HPDL).Design/methodology/approach: Metallographic examinations of the material structures after laser alloying of their surface layer were made on light microscope. The tribological wear relationships using pin-on-disc test were specified for surface layers subject to laser treatment, determi...

  17. Fatigue strain-life behavior of carbon and low-alloy steels, austenitic stainless steels, and Alloy 600 in LWR environments

    International Nuclear Information System (INIS)

    The existing fatigue strain vs. life (S-N) data, foreign and domestic, for carbon and low-alloy steels, austenitic stainless steels, and Alloy 600 used in the construction of nuclear power plant components have been compiled and categorized according to material, loading, and environmental conditions. Statistical models have been developed for estimating the effects of the various service conditions on the fatigue life of these materials. The results of a rigorous statistical analysis have been used to estimate the probability of initiating a fatigue crack. Data in the literature were reviewed to evaluate the effects of size, geometry, and surface finish of a component on its fatigue life. The fatigue S-N curves for components have been determined by adjusting the probability distribution curves for smooth test specimens for the effect of mean stress and applying design margins to account for the uncertainties due to component size/geometry and surface finish. The significance of the effect of environment on the current Code design curve and on the proposed interim design curves published in NUREG/CR-5999 is discussed. Estimations of the probability of fatigue cracking in sample components from BWRs and PWRs are presented

  18. Synthesis of electric discharge alloyed nickel–tungsten coating on tool steel and its tribological studies

    International Nuclear Information System (INIS)

    Highlights: • Electrical discharge alloying/coating made on AISI D2 tool steel. • The hardness of EDA layer is three to four time higher than the base material. • The dry sliding wear tests performed on EDA layer at different temperatures. • The alloyed layer acts as a self-lubricant at higher temperature. - Abstract: The present study examines the method of depositing nickel and tungsten on die steel surface by means of dispersing these elements in dielectric fluid in an electrical discharge alloying (EDA) process. The modified surface was mechanically and metallurgically characterized using Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), microhardness tester and Pin-on-disc tribometer. The phase transformations that occurred during EDA process were evaluated by XRD. The deposition of Ni and W on die steel surfaces yielded minimal cracks with excellent metallurgical bonding. Higher hardness (∼1059 HV0.3) with little brittleness resulted in superior wear resistance properties, a property which was retained even at elevated temperature

  19. Formation Energies and Electronic Properties of Vanadium Carbides Found in High Strength Steel Alloys

    Science.gov (United States)

    Limmer, Krista; Medvedeva, Julia

    2013-03-01

    Carbide formation and stabilization in steels is of great interest owing to its effect on the microstructure and properties of the Fe-based alloys. The appearance of carbides with different metal/C ratios strongly depends on the carbon concentration, alloy composition as well as the heat treatment. Strong carbide-forming elements such as Ti, V, and Nb have been used in microalloyed steels; with VC showing an increased solubility in the iron matrix as compared with TiC and NbC. This allows for dissolution of the VC into the steel during heating and fine precipitation during cooling. In addition to VC, the primary vanadium carbide with cubic structure, a wide range of non-stoichiometric compositions VCy with y varying from 0.72 to 0.88, has been observed. This range includes two ordered compounds, V8C7 and V6C5. In this study, first-principles density functional theory (DFT) is employed to examine the stability of the binary carbides by calculating their formation energies. We compare the local structures (atomic coordination, bond distances and angles) and the density of states in optimized geometries of the carbides. Further, the effect of alloying additions, such as niobium and titanium, on the carbide stabilization is investigated. We determine the energetically preferable substitutional atom location in each carbide and study the impurity distribution as well as its role in the carbide formation energy and electronic structure.

  20. Corrosion behaviour of stainless steel alloys in molten (Na,K)NO{sub 3} eutectic mixture

    Energy Technology Data Exchange (ETDEWEB)

    Attia, A.A. [Zagazik Univ. (Egypt). Chem. Dept.; Ali, A.-H.; Masri, A.N.A.; Baraka, A.M. [High Technological Inst., Ramadan Tenth City (Egypt)

    1999-09-01

    In the present article it is aimed to study the corrosion (oxidation) behaviour of two types of stainless steel alloys, ferritic (15.03% Cr) and austenitic (20.45% Cr, 8.37% Ni), in molten (Na, K)NO{sub 3} mixture at different temperatures ranging from 400-600 C. In this investigation the technique of potential-time and current-time under the open-circuit conditions is employed. The variation of potential with time at different temperatures was explained in terms of propagation and thickening of oxide film with a rate which depends on the temperature. It is assumed that the oxide film thickens according to a solid state mechanism under high field strength. The activation energy of the corrosion process was estimated using Arrhenius plots. The calculated values are found to be 21.36 KJ/mol for the ferritic stainless steel alloy and 23.3 KJ/mol for the austenitic one. The low value of activation energy signifies diffusion controlled process occurring in the oxide matrix. The corrosion products formed on the surface of stainless steel alloys are identified by X-ray diffraction analysis. Also the melt is chemically analysed to detect the amount of Fe, Cr and Ni in the melt after the completion of experiment. (orig.)

  1. Flow Stress Analysis and Hot Bending of P11 Alloy Steel

    Science.gov (United States)

    Ma, Fu-ye; Jin, Kai; Wang, Hui; Pei, Wen-Jiao; Tang, Xiao-Bin; Tao, Jie; Guo, Xun-Zhong

    2016-07-01

    Based on the growing application value of the P11 alloy steel in the nuclear power field, its dynamic recrystallization (DRX) behavior was firstly investigated by means of isothermal hot compression experiments, under the conditions of a testing temperature range between 800 and 950 °C, and a strain rate range between 0.01 and 2/s. Furthermore, optical microscopy and transmission electron microscopy were also employed to analyze the effect of the mechanism of the strain rate on DRX. The results indicated that the grain size could be significantly refined with the increase of strain rate. Also, the recrystallized volume fraction was increased and the dislocation density decreased with the decrease of strain rate, for the same strain values. Subsequently, numerical simulations, under the assistance of experimental results on DRX behavior, were successfully used to study the hot push bending process and simultaneously obtain the processing parameters of the actual work-pieces. Finally, some comparative analyses were performed and discussed in parallel with the deformed actual work-pieces. The EBSD results on the deformed P11 alloy steel were emphasized for exploring the forming properties of this alloy steel.

  2. Nickel-coated Steel Stud to Aluminum Alloy Joints Made by High Frequency Induction Brazing

    Institute of Scientific and Technical Information of China (English)

    GE Jiaqi; WANG Kehong; ZHANG Deku; WANG Jian

    2015-01-01

    Nickel-coated 45 steel studs and 6061 aluminum alloy with 4047 Al alloy foil asfi ller metal were joined by using high frequency induction brazing. The microstructure of Fe/Al brazed joint was studied by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD). Results showed that 45 steel stud and 6061 aluminum alloy could be successfully joined by high frequency induction brazing with proper processing parameters. The bonding strength of the joint was of the order of 88 MPa. Ni coating on steel stud successfully avoided the generation of Fe-Al intermetallic compound which is brittle by blocking the contact between Al and Fe. Intermetallic compounds, i e,Al3Ni2, Al1.1Ni0.9 and Al0.3Fe3Si0.7 presented in Al side, FeNi and Fe-Al-Ni ternary eutectic structure were formed in Fe side. The micro-hardness in intermetallic compound layer was 313 HV. The joint was brittle fractured in the intermetallic compounds layer of Al side, where plenty of Al3Ni2 intermetallic compounds were distributed continuously.

  3. Boronization and Carburization of Superplastic Stainless Steel and Titanium-Based Alloys

    Directory of Open Access Journals (Sweden)

    Masafumi Matsushita

    2011-07-01

    Full Text Available Bronization and carburization of fine-grain superplastic stainless steel is reviewed, and new experimental results for fine grain Ti88.5Al4.5V3Fe2Mo2 are reported. In superplastic duplex stainless steel, the diffusion of carbon and boron is faster than in non-superplastic duplex stainless steel. Further, diffusion is activated by uniaxial compressive stress. Moreover, non-superplastic duplex stainless steel shows typical grain boundary diffusion; however, inner grain diffusion is confirmed in superplastic stainless steel. The presence of Fe and Cr carbides or borides is confirmed by X-ray diffraction, which indicates that the diffused carbon and boron react with the Fe and Cr in superplastic stainless steel. The Vickers hardness of the carburized and boronized layers is similar to that achieved with other surface treatments such as electro-deposition. Diffusion of boron into the superplastic Ti88.5Al4.5V3Fe2Mo2 alloy was investigated. The hardness of the surface exposed to boron powder can be increased by annealing above the superplastic temperature. However, the Vickers hardness is lower than that of Ti boride.

  4. Laser Surface Alloying of 316L Stainless Steel with Ru and Ni Mixtures

    Directory of Open Access Journals (Sweden)

    M. B. Lekala

    2012-01-01

    Full Text Available The surfaces of AISI 316L stainless steel were laser alloyed with ruthenium powder and a mixture of ruthenium and nickel powders using a cw Nd:YAG laser set at fixed operating parameters. The microstructure, elemental composition, and corrosion characteristics of the alloyed zone were analyzed using optical and scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDX, and corrosion potential measurements. The depth of alloyed zone was measured using the AxioVision program and found to be approximately 1.8 mm for all the alloyed specimens. Hardness profile measurements through the surface-substrate interface showed a significant increase from 160 HV for the substrate to a maximum of 247 HV for the alloyed layer. The sample laser alloyed with 80 wt% Ni-20 wt% presented the most noble corrosion potential (Ecorr of −0.18 V and the lowest corrosion current density (icorr.

  5. Effect of Cr content on the corrosion performance of low-Cr alloy steel in a CO2 environment

    Science.gov (United States)

    Xu, Lining; Wang, Bei; Zhu, Jinyang; Li, Wei; Zheng, Ziyi

    2016-08-01

    Low-Cr alloy steel demonstrates lower corrosion rate than does C steel in a high-temperature and high-pressure CO2-containing environment. This study aimed to clarify the role of the Cr content in mitigating corrosion and reports the performance of 1%Cr, 2%Cr, 3%Cr, 4%Cr, 5%Cr, and 6.5%Cr steels. The results show that low-Cr alloy steel in CO2 at 80 °C and 0.8 MPa possesses spontaneous prepassivation characteristics when the Cr content is 3% or higher. Furthermore, the formation and peel-off of a prepassivation film on 3%Cr-6.5%Cr steels surfaces during polarization demonstrate that adequate amount of Cr in the steel substrate can cause protective layer. The main component of prepassivation film on 3%Cr steel is Cr(OH)3. Thus, the role of Cr is revealed. An adequate amount of Cr in the steel substrate causes the formation of protective Cr(OH)3 layer, which helps low-Cr steel to possess prepassivation characteristics. Prepassivation is the reason why low-Cr steel has a lower corrosion rate than C steel.

  6. The measurement of phosphorus in low alloy steels by electrochemical methods

    International Nuclear Information System (INIS)

    The oscillo-polarographic method reported by Chen for the determination of phosphorus in silicates, iron ores, carbonates and tea leaves has been thoroughly studied and enhanced in view of the determination of P in various steels. Together with a carefully selected sample dissolution method, the chromatographic separation reported by Hanada et al. for eliminating the matrix has also been examined. The results of these investigations allowed finding out a path towards the successful electrochemical measurement of P in low alloy ferritic steels without eliminating the matrix. The limit of detection is 5.2 micro gram-1 in the metal. The precision ranges between 5 and 15 % relative to the mean measured values. The finely tuned method has been successfully validated using five NIST standard steels. The chromatographic method remains an option for addressing other metals in the future, should they contain unacceptable levels of possibly interfering elements.. Detailed experimental procedures are given.

  7. Mechanism of laser welding on dissimilar metals between stainless steel and W-Cu alloy

    Institute of Scientific and Technical Information of China (English)

    Kai Chen; Zhiyong Wang; Rongshi Xiao; Tiechuan Zuo

    2006-01-01

    @@ CO2 laser is employed to join a piece of powder metallurgical material (PMM) to a stainless steel in butt joint welding mode. The powder Ni35, as a filler powder, is used. The weld metal comes from three parts of stainless steel, powder Ni35, and Cu in W-Cu PMM. It is indicated that some parts of the W-Cu base metal are heated by laser and the metal Cu at the width of 0.06-0.12 mm from the edge is melted into the melting pool in the laser welding process. The formation of firm weld joint is just because that the melting liquid metal could fill the position occupied by metal Cu and surround the metal W granules fully. The analysis results indicate that the mechanism of the laser welding for stainless steel and W-Cu alloy is a special mode of fusion-brazing welding.

  8. Intergranular brittle fracture of a low alloy steel. Global and local approaches

    International Nuclear Information System (INIS)

    The intergranular brittle fracture of a low alloy steel (A533B.Cl1) is studied: an embrittlement heat treatment is used to develop two brittle 'states' that fail through an intergranular way at low temperatures. This mode of fracture leads to an important shift of the transition temperature (∼ 165 deg C) and a decrease in the fracture toughness. The local approach to fracture, developed for cleavage, is applied to the case of intergranular fracture. Modifications are proposed. The physical supports of these models are verified by biaxial (tension-torsion) tests. From the local approaches developed for intergranular fracture, the static and dynamic fracture toughness of the embrittled steel is predicted. The local approach applied to a structural steel, which presents mixed modes of fracture (cleavage and intergranular), showed that this mode of fracture seems to be controlled by intergranular loss of cohesion

  9. Origin and dispersion strengthening of carbonitrides in a commercial hot strip micro alloyed niobium steel

    International Nuclear Information System (INIS)

    Throughout this work, a study on niobium carbonitrides formation and its hardening effect in a commercial hot strip micro alloyed steel is presented. Optic and electron micrographs were obtained while mechanical tests and indirect models allow to predict samples yield strength, taking into account the steel composition and its structural characteristics. The results showed an extended precipitation on austenite boundary cells during the last thermomechanical processing stages, which probably achieved a considerable contribution to the hardening by dispersion in the material studied. Otherwise, no evidence of precipitation in ferrite by means of transmission electron microscopy (TEM) was observed. A poor interphase precipitation was detected in about 10 per cent of the total observed zones with no appreciated contribution to the steel hardness. (Author) 28 refs

  10. The measurement of phosphorus in low alloy steels by electrochemical methods

    Energy Technology Data Exchange (ETDEWEB)

    Rahier, A.; Campsteyn, A.; Verheyen, E.; Verpoucke, G.

    2008-08-15

    The oscillo-polarographic method reported by Chen for the determination of phosphorus in silicates, iron ores, carbonates and tea leaves has been thoroughly studied and enhanced in view of the determination of P in various steels. Together with a carefully selected sample dissolution method, the chromatographic separation reported by Hanada et al. for eliminating the matrix has also been examined. The results of these investigations allowed finding out a path towards the successful electrochemical measurement of P in low alloy ferritic steels without eliminating the matrix. The limit of detection is 5.2 micro gram{sup -1} in the metal. The precision ranges between 5 and 15 % relative to the mean measured values. The finely tuned method has been successfully validated using five NIST standard steels. The chromatographic method remains an option for addressing other metals in the future, should they contain unacceptable levels of possibly interfering elements.. Detailed experimental procedures are given.

  11. Microstructure and mechanical properties of a new type of austempered boron alloyed high silicon cast steel

    Directory of Open Access Journals (Sweden)

    Chen Xiang

    2013-05-01

    Full Text Available In the present paper, a new type of austempered boron alloyed high silicon cast steel has been developed, and its microstructures and mechanical properties at different temperatures were investigated. The experimental results indicate that the boron alloyed high silicon cast steel comprises a dendritic matrix and interdendritic eutectic borides in as-cast condition. The dendritic matrix is made up of pearlite, ferrite, and the interdendritic eutectic boride is with a chemical formula of M2B (M represents Fe, Cr, Mn or Mo which is much like that of carbide in high chromium white cast iron. Pure ausferrite structure that consists of bainitic ferrite and retained austenite can be obtained in the matrix by austempering treatment to the cast steel. No carbides precipitate in the ausferrite structure and the morphology of borides remains almost unchanged after austempering treatments. Secondary boride particles precipitate during the course of austenitizing. The hardness and tensile strength of the austempered cast steel decrease with the increase of the austempering temperature, from 250 篊 to 400 篊. The impact toughness is 4-11 J昪m-2 at room temperature and the impact fracture fractogragh indicates that the fracture is caused by the brittle fracture of the borides.

  12. Systematic investigation of the fatigue performance of a friction stir welded low alloy steel

    International Nuclear Information System (INIS)

    Highlights: • The fatigue behaviour of a friction stir welded low alloy steel has been assessed. • The welds’ fatigue lives outperform the International Institute of Welding’s recommendations for fusion welds. • The slow weld exhibits the best fatigue performance of the investigated welds. • Fracture surface analysis shows that minor embedded flaws do not offer crack initiation sites. • Process-related surface breaking flaws have a significant effect on the fatigue life. - Abstract: A comprehensive fatigue performance assessment of friction stir welded DH36 steel has been undertaken to address the relevant knowledge gap for this process on low alloy steel. A detailed set of experimental procedures specific to friction stir welding has been put forward, and the consequent study extensively examined the weld microstructure and hardness in support of the tensile and fatigue testing. The effect of varying welding parameters was also investigated. Microstructural observations have been correlated to the weldments’ fatigue behaviour. The typical fatigue performance of friction stir welded steel plates has been established, exhibiting fatigue lives well above the weld detail class of the International Institute of Welding even for tests at 90% of yield strength, irrespective of minor instances of surface breaking flaws which have been identified. An understanding of the manner in which these flaws impact on the fatigue performance has been established, concluding that surface breaking irregularities such as these produced by the tool shoulder’s features on the weld top surface can be the dominant factor for crack initiation under fatigue loading

  13. Effect of Mn Content and Solution Annealing Temperature on the Corrosion Resistance of Stainless Steel Alloys

    Directory of Open Access Journals (Sweden)

    Ihsan-ul-Haq Toor

    2014-01-01

    Full Text Available The corrosion behavior of two specially designed austenitic stainless steels (SSs having different Nickel (Ni and Manganese (Mn contents was investigated. Prior to electrochemical tests, SS alloys were solution-annealed at two different temperatures, that is, at 1030°C for 2 h and 1050°C for 0.5 h. Potentiodynamic polarization (PD tests were carried out in chloride and acidic chloride, whereas linear polarization resistance (LPR and electrochemical impedance spectroscopy (EIS was performed in 0.5 M NaCl solution at room temperature. SEM/EDS investigations were carried out to study the microstructure and types of inclusions present in these alloys. Experimental results suggested that the alloy with highest Ni content and annealed at 1050°C/0.5 hr has the highest corrosion resistance.

  14. Electroless plating of Ni-Zn(Fe)-P alloy on carbon steel sheets

    Institute of Scientific and Technical Information of China (English)

    WANG Sen-lin; WU Hui-huang

    2004-01-01

    The autocatalytic deposition of Ni-Zn(Fe)-P alloys were carried out on carbon steel sheets from bath containing nickel sulfate, zinc sulfate, sodium hypophosphite, sodium citrate and boric acid. The effects of pH and mole ratio of NiSO4/ZnSO4 on the deposition rate and the composition of deposit were studied. It is found that the presence of zinc sulfate in the bath has an inhibitory effect on the alloy deposition. As a consequence, the mole fraction of zinc in the deposits never reaches high value, which is less than 18.0%. The structure and surface morphology of Ni-Zn(Fe)-P coatings were charactered by XRD and SEM. The alloys plated at all conditions consist of amorphous phase coexisting with a crystalline cubic Ni phase. The surface morphology of coating is dependent on the deposition parameters.

  15. ATR-A1 irradiation experiment on vanadium alloys and low activation steels

    Energy Technology Data Exchange (ETDEWEB)

    Tasi, H.; Strain, R.V.; Gomes, I.; Hins, A.G.; Smith, D.L.

    1996-04-01

    To study the mechanical properties of vanadium alloys under neutron irradiation at low temperatures, an experiment was designed and constructed for irradiation in the Advanced Test Reactor (ATR). The experiment contained Charpy, tensile, compact tension, TEM, and creep specimens of vanadium alloys. It also contained limited low-activation ferritic steel specimens as part of the collaborative agreement with Monbusho of Japan. The design irradiation temperatures for the vanadium alloy specimens in the experiment are {approx}200 and 300{degrees}C, achieved with passive gap-gap sizing and fill gas blending. To mitigate vanadium-to-chromium transmutation from the thermal neutron flux, the test specimens are contained inside gadolinium flux filters. All specimens are lithium-bonded. The irradiation started in Cycle 108A (December 3, 1995) and is expected to have a duration of three ATR cycles and a peak influence of 4.4 dpa.

  16. Atom probe study of the microstructural evolution induced by irradiation in Fe-Cu ferritic alloys and pressure vessel steels

    International Nuclear Information System (INIS)

    Pressure vessel steels used in pressurized water reactors are low alloyed ferritic steels. They may be prone to hardening and embrittlement under neutron irradiation. The changes in mechanical properties are generally supposed to result from the formation of point defects, dislocation loops, voids and/or copper rich clusters. However, the real nature of the irradiation induced-damage in these steels has not been clearly identified yet. In order to improve our vision of this damage, we have characterized the microstructure of several steels and model alloys irradiated with electrons and neutrons. The study was performed with conventional and tomographic atom probes. The well known importance of the effects of copper upon pressure vessel steel embrittlement has led us to study Fe-Cu binary alloys. We have considered chemical aging as well as aging under electron and neutron irradiations. The resulting effects depend on whether electron or neutron irradiations ar used for thus. We carried out both kinds of irradiation concurrently so as to compare their effects. We have more particularly considered alloys with a low copper supersaturation representative of that met with the French vessel alloys (0.1% Cu). Then, we have examined steels used on French nuclear reactor pressure vessels. To characterize the microstructure of CHOOZ A steel and its evolution when exposed to neutrons, we have studied samples from the reactor surveillance program. The results achieved, especially the characterization of neutron-induced defects have been compared with those for another steel from the surveillance program of Dampierre 2. All the experiment results obtained on model and industrial steels have allowed us to consider an explanation of the way how the defects appear and grow, and to propose reasons for their influence upon steel embrittlement. (author). 3 appends

  17. The microstructural, mechanical, and fracture properties of austenitic stainless steel alloyed with gallium

    Science.gov (United States)

    Kolman, D. G.; Bingert, J. F.; Field, R. D.

    2004-11-01

    The mechanical and fracture properties of austenitic stainless steels (SSs) alloyed with gallium require assessment in order to determine the likelihood of premature storage-container failure following Ga uptake. AISI 304 L SS was cast with 1, 3, 6, 9, and 12 wt pct Ga. Increased Ga concentration promoted duplex microstructure formation with the ferritic phase having a nearly identical composition to the austenitic phase. Room-temperature tests indicated that small additions of Ga (less than 3 wt pct) were beneficial to the mechanical behavior of 304 L SS but that 12 wt pct Ga resulted in a 95 pct loss in ductility. Small additions of Ga are beneficial to the cracking resistance of stainless steel. Elastic-plastic fracture mechanics analysis indicated that 3 wt pct Ga alloys showed the greatest resistance to crack initiation and propagation as measured by fatigue crack growth rate, fracture toughness, and tearing modulus. The 12 wt pct Ga alloys were least resistant to crack initiation and propagation and these alloys primarily failed by transgranular cleavage. It is hypothesized that Ga metal embrittlement is partially responsible for increased embrittlement.

  18. Solid particle erosion of steels and nickel based alloys candidates for USC steam turbine blading

    Energy Technology Data Exchange (ETDEWEB)

    Cernuschi, Federico; Guardamagna, Cristina; Lorenzoni, Lorenzo [ERSE SpA, Milan (Italy); Robba, Davide [CESI, Milan (Italy)

    2010-07-01

    The main objective of COST536 Action is to develop highly efficient steam power plant with low emissions, from innovative alloy development to validation of component integrity. In this perspective, to improve the operating efficiency, materials capable of withstanding higher operating temperatures are required. For the manufacturing of components for steam power plants with higher efficiency steels and nickel-based alloys with improved oxidation resistance and creep strength at temperature as high as 650 C - 700 C have to be developed. Candidate alloys for manufacturing high pressure steam turbine diaphragms, buckets, radial seals and control valves should exhibit, among other properties, a good resistance at the erosion phenomena induced by hard solid particles. Ferric oxide (magnetite) scales cause SPE by exfoliating from boiler tubes and steam pipes (mainly super-heaters and re-heaters) and being transported within the steam flow to the turbine. In order to comparatively study the erosion behaviour of different materials in relatively short times, an accelerated experimental simulation of the erosion phenomena must be carried out. Among different techniques to induce erosion on material targets, the use of an air jet tester is well recognised to be one of the most valid and reliable. In this work the results of SPE comparative tests performed at high temperatures (550 C, 600 C and 650 C) at different impaction angles on some steels and nickel based alloys samples are reported. (orig.)

  19. Structure and mechanical properties of the three-layer material based on a vanadium alloy and corrosion-resistant steel

    Science.gov (United States)

    Nikulin, S. A.; Rozhnov, A. B.; Nechaikina, T. A.; Rogachev, S. O.; Zavodchikov, S. Yu.; Khatkevich, V. M.

    2014-10-01

    The quality of three-layer pipes has been studied; they are manufactured by hot pressing of a three-layer assembly of tubular billets followed by forging and cold rolling. The operating core is made from a V-4Ti-4Cr alloy. The protective claddings are made from corrosion-resistant steels of two grades, 08Kh17T and 20Kh13. The results of investigation into the structure and microhardness of the junction zone of steel and the vanadium alloy, which includes a contact zone and a transition diffusion layer, are reported. The 08Kh17T steel is shown to be a preferred cladding material.

  20. Crack growth kinetics across weld interface between Alloy 182 and low Alloy steel and that between Alloy 182 and metals to simulate weld dilution zone

    International Nuclear Information System (INIS)

    Crack growth kinetics across weld interface between Alloy 182 and LAS (Low Alloy Steel) and that between Alloy 182 and Metals to simulate weld dilution zone was investigated by CBB (Creviced Bent Beam) test. The main objective of this study is to investigate dynamic influence for a crack initiated in Alloy 182 to propagate into LAS. Specimens were subjected to CBB tests for 2000 h each in simulated BWR water with 8 ppm of dissolved oxygen. Mechanics conditions were described by equivalent stress intensity factor KJ values which are J values from elasto-plastic analysis. In small-sized specimens of 2 mm in thickness, cracks which initiated in Alloy 182 propagated into Metal21-4 (20%Ni, 4%Cr), while they did not into Metal21-5 (10%Ni, 2%Cr). In moderate-sized specimens of 10 mm in thickness, cracks did advance into Metals and LAS under KJ values more than 80 MPa·m1/2. (author)

  1. Laser surface treatment of the hot work tool steel alloyed with TaC and VC carbide powders

    OpenAIRE

    L.A. Dobrzański; E. Jonda; Klimpel, A

    2009-01-01

    Purpose: The paper presents investigation results of the structure and properties of alloying surface layer of the X40CrMoV5-1 hot work tool steel, using the high power diode laser HPDL. Tantalum and vanadium carbides powders were used for alloying and the X40CrMoV5-1 conventionally heat treated steel was used as reference material.Design/methodology/approach: Metallographic examinations of the material structures after laser alloying surface layer were made on light microscope and transmissi...

  2. Neutron irradiation test of copper alloy/stainless steel joint materials

    International Nuclear Information System (INIS)

    As a study about the joint technology of copper alloy and stainless steel for utilization as cooling piping in International Thermonuclear Experimental Reactor (ITER), Al2O3-dispersed strengthened copper or CuCrZr was jointed to stainless steel by three kinds of joint methods (casting joint, brazing joint and friction welding method) for the evaluation of the neutron irradiation effect on joints. A neutron irradiation test was performed to three types of joints and each copper alloy. The average value of fast neutron fluence in this irradiation test was about 2 x 1024n/m2(E>1 MeV), and the irradiation temperature was about 130degC. As post-irradiation examinations, tensile tests, hardness tests and observation of fracture surface after the tensile tests were performed. All type joints changed to be brittle by the neutron irradiation effect like each copper alloy material, and no particular neutron irradiation effect due to the effect of joint process was observed. On the casting and friction welding, hardness of copper alloy near the joint boundary changed to be lower than that of each copper alloy by the effect of joint procedure. However, tensile strength of joints was almost the same as that of each copper alloy before/after neutron irradiation. On the other hand, tensile strength of joints by brazing changed to be much lower than CuAl-25 base material by the effect of joint process before/after neutron irradiation. Results in this study showed that the friction welding method and the casting would be able to apply to the joint method of piping in ITER. This report is based on the final report of the ITER Engineering Design Activities (EDA). (author)

  3. Enhancement of mechanical properties of alloy steels on hot forging

    International Nuclear Information System (INIS)

    The paper present the results of an investigation into the effects of the basic parameters of high-temperature thermomechanical treatment (HTTMT) under hot forging. It is shown that forging in open dies of 45Kh, 20Kh13 and 08Kh18N10T steel blanks following the established HTTMT modes improves the ultimate strength by 46, 56 and 2% respectively, and yield limit - by 65, 66 and 14%, as compared with their production in compliance with factory modes, preserving the level of ductility and impact strength

  4. Mechanical properties and hot-rolled microstructures of a low carbon bainitic steel with Cu-P alloying

    Energy Technology Data Exchange (ETDEWEB)

    Cui, W.F., E-mail: wenfangcui@yahoo.com.cn [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China); Zhang, S.X. [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China); Technology Center of Laiwu Iron and Steel (Group) Co. Ltd., Laiwu 271104 (China); Jiang, Y. [School of Chemical Engineering, University of Queensland, Brisbane 4072 (Australia); Dong, J. [Technology Center of Laiwu Iron and Steel (Group) Co. Ltd., Laiwu 271104 (China); Liu, C.M. [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China)

    2011-08-15

    Highlights: {yields} Mechanical properties and microstructures of low carbon bainite steel are examined. {yields} Cu-P alloying promotes strengthening and uniform plastic deformation. {yields} Cu-P alloying delays recovery process during rolling interval. {yields} Lowering rolling temperature is favorable to increasing toughness. - Abstract: A low carbon bainitic steel with Cu-P alloying was developed. The new steel aims to meet the demand of high strength, high toughness and resistance to chloride ion corrosion for the components used in the environment of sea water and oceanic atmosphere. Mechanical properties of the steel were tested and strengthening and toughening mechanisms were analyzed by comparing hot-rolled microstructures of the low carbon bainitic steels with and without Cu-P alloying. The results show that Cu-P alloying provided strong solution strengthening with weak effect on ductility. The toughness loss caused by Cu-P alloying could be balanced by increasing the amount of martensite/remained austenite (M/A island) at lower finishing temperature. The static recovery process during rolling interval was delayed by the interaction of phosphorous, copper atoms with dislocations, which was favorable to the formation of bainitic plates. Super-fine Nb(C, N) particles precipitated on dislocations had coherency with bainite ferrite at 830 deg. C finishing temperature. Raising finishing temperature to 880 deg. C, Nb(C, N) particles were prone to coarsening and losing coherency. It was also found that no accurate lattice match relationship among retained austenite, martensite and bainite in granular bainitic microstructure.

  5. Mechanical properties and hot-rolled microstructures of a low carbon bainitic steel with Cu-P alloying

    International Nuclear Information System (INIS)

    Highlights: → Mechanical properties and microstructures of low carbon bainite steel are examined. → Cu-P alloying promotes strengthening and uniform plastic deformation. → Cu-P alloying delays recovery process during rolling interval. → Lowering rolling temperature is favorable to increasing toughness. - Abstract: A low carbon bainitic steel with Cu-P alloying was developed. The new steel aims to meet the demand of high strength, high toughness and resistance to chloride ion corrosion for the components used in the environment of sea water and oceanic atmosphere. Mechanical properties of the steel were tested and strengthening and toughening mechanisms were analyzed by comparing hot-rolled microstructures of the low carbon bainitic steels with and without Cu-P alloying. The results show that Cu-P alloying provided strong solution strengthening with weak effect on ductility. The toughness loss caused by Cu-P alloying could be balanced by increasing the amount of martensite/remained austenite (M/A island) at lower finishing temperature. The static recovery process during rolling interval was delayed by the interaction of phosphorous, copper atoms with dislocations, which was favorable to the formation of bainitic plates. Super-fine Nb(C, N) particles precipitated on dislocations had coherency with bainite ferrite at 830 deg. C finishing temperature. Raising finishing temperature to 880 deg. C, Nb(C, N) particles were prone to coarsening and losing coherency. It was also found that no accurate lattice match relationship among retained austenite, martensite and bainite in granular bainitic microstructure.

  6. Effect of Aluminum and Silicon on Atmospheric Corrosion of Low-alloying Steel under Containing NaHSO3 Wet/dry Environment

    International Nuclear Information System (INIS)

    The atmospheric corrosion performance of Al-alloying Si-alloying and Al-Si-alloying steel were studied by wet/dry cyclic corrosion tests (CCT) at 30 .deg. C and 60% relative humidity (RH). The corrosion electrolyte used for CCT was 0.052 wt% NaHSO3 (pH∼4) solution. The result of gravimetry demonstrated that Al-Si-bearing steels showed lower corrosion resistance than other rusted steels. But the rusted 0.7%Si-alloying steel showed a better corrosion resistance than rusted mild steel. Polarization curves demonstrated that Al-/Si-alloying and Al-Si-alloying improved the rest potential of steel at the initial stage: and accelerated the cathodic reduction and anodic dissolution after a rust layer formed on the surfaces of steels. XRD results showed that Al-Si-alloying decreased the volume fraction of Fe3O4 and α-FeOOH. The recycle of acid accelerated the corrosion of steel at the initial stage. After the rust layer formed on the steel, the leak of rust destabilized the rust layer due to the dissolution of compound containing Al (such as FeAl2O4, (Fe, Si)2(Fe, Al)O4). Al-Si-alloying is hence not suitable for improving the anti-corrosion resistance of steel in industrial atmosphere

  7. Effect of Aluminum and Silicon on Atmospheric Corrosion of Low-alloying Steel under Containing NaHSO{sub 3} Wet/dry Environment

    Energy Technology Data Exchange (ETDEWEB)

    Xinhua, Chen; Junhua, Dong; Enhou, Han; Wei, Ke [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China)

    2008-12-15

    The atmospheric corrosion performance of Al-alloying Si-alloying and Al-Si-alloying steel were studied by wet/dry cyclic corrosion tests (CCT) at 30 .deg. C and 60% relative humidity (RH). The corrosion electrolyte used for CCT was 0.052 wt% NaHSO{sub 3} (pH{approx}4) solution. The result of gravimetry demonstrated that Al-Si-bearing steels showed lower corrosion resistance than other rusted steels. But the rusted 0.7%Si-alloying steel showed a better corrosion resistance than rusted mild steel. Polarization curves demonstrated that Al-/Si-alloying and Al-Si-alloying improved the rest potential of steel at the initial stage: and accelerated the cathodic reduction and anodic dissolution after a rust layer formed on the surfaces of steels. XRD results showed that Al-Si-alloying decreased the volume fraction of Fe{sub 3}O{sub 4} and {alpha}-FeOOH. The recycle of acid accelerated the corrosion of steel at the initial stage. After the rust layer formed on the steel, the leak of rust destabilized the rust layer due to the dissolution of compound containing Al (such as FeAl{sub 2}O{sub 4}, (Fe, Si){sub 2}(Fe, Al)O{sub 4}). Al-Si-alloying is hence not suitable for improving the anti-corrosion resistance of steel in industrial atmosphere.

  8. Stainless steel-zirconium alloy waste forms for metallic fission products and actinides during treatment of spent nuclear fuel

    International Nuclear Information System (INIS)

    Stainless steel-zirconium waste form alloys are being developed for the disposal of metallic wastes recovered from spent nuclear fuel using an electrometallurgical process developed by Argonne National Laboratory. The metal waste form comprises the fuel cladding, noble metal fission products and other metallic constituents. Two nominal waste form compositions are being developed: (1) stainless steel-15 wt% zirconium for stainless steel-clad fuels. The noble metal fission products are the primary source of radiation and their contribution to the waste form radioactivity has been calculated. The disposition of actinide metals in the waste alloys is also being explored. Simulated waste form alloys were prepared to study the baseline alloy microstructures and the microstructural distribution of noble metals and actinides, and to evaluate corrosion performance

  9. Compatibility of graphite with a martensitic-ferritic steel, an austenitic stainless steel and a Ni-base alloy up to 1250 C

    International Nuclear Information System (INIS)

    To study the chemical interactions between graphite and a martensitic-ferritic steel (1.4914), an austenitic stainless steel (1.4919; AISI 316), and a Ni-base alloy (Hastelloy X) isothermal reaction experiments were performed in the temperature range between 900 and 1250 C. At higher temperatures a rapid and complete liquefaction of the components occurred as a result of eutectic interactions. The chemical interactions are diffusion-controlled processes and can be described by parabolic rate laws. The reaction behavior of the two steels is very similar. The chemical interactions of the steels with graphite are much faster above 1100 C than those for the Ni-base alloy. Below 1000 C the effect is opposite. (orig.)

  10. Alloying effects on microstructure formation of dual phase steels

    International Nuclear Information System (INIS)

    In dual-phase (DP) steels, inherited microstructures and elemental distributions affect the kinetics and morphology of phase transformation phenomena and the mechanical properties of the final material. In order to study the inheritance process, we selected two model materials with the same average DP steel composition but with different initial microstructures, created by coiling at different temperatures after hot rolling. These samples were submitted to a DP-steel heat treatment consisting of a short isothermal annealing in the pure austenite region and a quenching process. The evolution of microstructure, chemical composition and mechanical properties (hardness) during this treatment was investigated. The initial samples had a bainitic–martensitic (B + M) microstructure for the material coiled at lower temperature and a ferritic–pearlitic (P + F) microstructure for that coiled at higher temperature. The P + F microstructure had a much more inhomogeneous distribution of substitutional elements (in particular of Mn) and of carbon. After complete heat treatment, both materials showed a typical DP microstructure (martensite islands embedded in ferrite) but the P + F material showed lower hardness compared to the B + M material. It was found that the inhomogeneous elemental distribution prevailed in the P + F material. The inheritance process was studied by combining measurements of the elemental distribution by Wavelength-Dispersive X-ray spectroscopy (WDX), simulations of the evolution of the elemental composition via the DICTRA (diffusion-controlled reactions) computer programme, dilatometry to observe the kinetics of phase transformation, and observation and quantification of the microstructures by Electron Backscatter Diffraction (EBSD) measurements. For the P + F material it was found that the α–γ transformation during annealing is slowed down in regions of lower Mn content and is therefore not completed. During the subsequent cooling the incompletely

  11. Role of alloyed molybdenum in austenitic stainless steels in the inhibition of pitting in neutral halide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, K.; Sawada, Y.

    1976-09-01

    In the passive region of austenitic stainless steels alloyed with Mo, the formation of MoO/sub 4//sup 2 -/ ions can be expected in neutral halide solutions by the transpassive dissolution of Mo. It has been shown that MoO/sub 4//sup 2 -/ ions added to neutral NaCl solutions act as an effective inhibitor against pitting of austenitic stainless steels with and without Mo. The interaction between alloyed Mo in the steels and added MoO/sub 4//sup 2 -/ ions in the solutions is appreciable. It is likely that the inhibition of pit growth by the adsorption of MoO/sub 4//sup 2 -/ ions which are thought to result from the dissolution of the steels at the initial stage of pitting leads to increased pitting resistance of austenitic stainless steels containing Mo.

  12. Influence of alloying on hydrogen-assisted cracking and diffusible hydrogen content in Cr–Mo steel welds

    Indian Academy of Sciences (India)

    S K Albert; V Ramasubbu; N Parvathavarthini; T P S Gill

    2003-06-01

    Study of hydrogen-assisted cracking and measurement of diffusible hydrogen content in different Cr–Mo steel welds shows that under identical conditions, susceptibility to cracking increased and diffusible hydrogen content decrease with increase in alloy content. Hydrogen permeation studies show that hydrogen diffusivity decreases and solubility increases with increase in alloy content. Thus decrease in diffusible hydrogen content with increase in alloying is attributed to increase in apparent solubility and decrease in apparent diffusivity of hydrogen. Analysis of the results indicates that variation of diffusible hydrogen content and apparent diffusivity of hydrogen with alloy content can be represented as a function of carbon equivalent CE1 originally proposed to predict the hardness in the heat-affected zone of alloy steel welds.

  13. Fatigue crack propagation in carburized high alloy bearing steels

    Science.gov (United States)

    Averbach, B. L.; Lou, Bingzhe; Pearson, P. K.; Fairchild, R. E.; Bamberger, E. N.

    1985-07-01

    Fatigue cracks were propagated through carburized cases in M-50NiL (0.1 C,4 Mo, 4 Cr, 1.3 V, 3.5 Ni) and CBS-1000M (0.1 C, 4.5 Mo, 1 Cr, 0.5 V, 3 Ni) steels at constant stress intensity ranges, ΔK, and at a constant cyclic peak load. Residual compressive stresses of the order of 140 MPa (20 Ksi) were developed in the M-50NiL cases, and in tests carried out at constant ΔK values it was observed that the fatigue crack propagation rates, da/dN, slowed significantly. In some tests, at constant peak loads, cracks were stopped in regions with high compressive stresses. The residual stresses in the cases in CBS-1000M steel were predominantly tensile, probably because of the presence of high retained austenite contents, and da/dN was accelerated in these cases. The effects of residual stress on the fatigue crack propagation rates are interpreted in terms of a pinched clothespin model in which the residual stresses introduce an internal stress intensity, Ki where Ki, = σid{i/1/2} (σi = internal stress, di = characteristic distance associated with the internal stress distribution). The effective stress intensity becomes Ke = Ka + Ki where Ka is the applied stress intensity. Values of Ki were calculated as a function of distance from the surface using experimental measurements of σi and a value of di = 11 mm (0.43 inch). The resultant values of Ke were taken to be equivalent to effective ΔK values, and da/dN was determined at each point from experimental measurements of fatigue crack propagation obtained separately for the case and core materials. A reasonably good fit was obtained with data for crack growth at a constant ΔK and at a constant cyclic peak load. The carburized case depths were approximately 4 mm, and the possible effects associated with the propagation of short cracks were considered. The major effects were observed at crack lengths of about 2 mm, but the contributions of short crack phenomena were considered to be small in these experiments, since the

  14. On fracture toughness decrease in low alloy steel under irradiation

    International Nuclear Information System (INIS)

    Mechanism of fracture toughness decrease under the effect of irradiation in steels 15Kh2MFA and 15Kh3NMFA-A has been investigated. Samples with cracks irradiated in BOR-60 and WWR-M type reactos were tested for eccentric tension at the temperature from - 196 deg C to 100 deg C. A decrease in the value KIcmin under the effect of irradiation, which agrees with the notions on relation of the phenomenon to the relaxation of residual stresses in the crack vertex, is detected. Resumption of KIcmin value can not be attained even in the case of radiation embrittlement elimination by annealing. The value can be increased only by means of loading up to KI > KIcmin in the temperature region of ductile fracture

  15. Improvement of resistance to oxidation by laser alloying on a tool steel

    Energy Technology Data Exchange (ETDEWEB)

    Gemellli, E.; Gallerie, A.; Caillet, M.

    1998-10-13

    The goal of this work is to improve the resistance to oxidation at high temperature of a tool steel (D2) without degrading its satisfactory tribologic properties. In a recent paper, the authors showed that the combination in the same coating, of chromium and silicon can provide increased resistance to oxidation at high temperature, a combination which until then had been used only in massive alloys. The present investigation deals with a steel initially having 12% chromium. The addition of silicon to the steel surface should improve the resistance to oxidation to the minimum levels required by the steel high operating temperatures. On the other hand, it has also been shown that the chromium and carbon addition leads to the formation o hard phases [(Fe,Cr){sub 7}C{sub 3}] necessary for a good anti-wear behavior. The increase of the chromium concentration in solid solution and the presence of carbide in the coating, obtained by the addition of Cr{sub 3}C{sub 2}, should then increase not only the resistance to oxidation, but also the resistance to wear. The possibility of obtaining the same effects by the addition o silicon carbide or chromium carbide to the D2 steel surface has also been investigated.

  16. Study of interactions between liquid lead-lithium alloy and austenitic and martensitic steels

    International Nuclear Information System (INIS)

    In the framework of Fusion Technology, the behaviour of structural materials in presence of liquid alloy Pb17Li is investigated. First, the diffusion coefficients of Fe and Cr have been determined at 500 deg C. Then mass transfer experiments in Pb17Li have been conducted in an anisothermal container with pure metals (Fe, Cr, Ni), Fe-Cr steels and austenitic steels. These experiments showed a very high loss of Nickel, which is an accordance with its high solubility, and Cr showed mass-losses one order of magnitude higher than for pure iron, as the diffusion coefficient of Cr is three orders of magnitude higher than for pure Fe. The corrosion rate of binary Fe-Cr and pure Fe are identical. In austenitic steels, the gamma lattice allows a higher mass-transfer of Cr than the alpha lattice, the presence of Cr slows downs the dissolution of Ni, and the porosity of corrosion layers results of losses of Cr and Ni. Finally, a review of our results and those of other laboratories allowed an identification of the corrosion limiting step. In the case of 1.4914 martensitic steel it is the diffusion of Fe in Pb17Li, while in the case of 316L austenitic steel it is the diffusion of Cr in Pb17Li

  17. Effects of alloying elements on sticking occurring during hot rolling of ferritic stainless steels

    International Nuclear Information System (INIS)

    In this study, effects of alloying elements on the sticking occurring during hot rolling of five kinds of ferritic STS430J1L stainless steels were investigated by analyzing high-temperature hardness and oxidation behavior of the rolled steels. Hot-rolling simulation tests were conducted by a high-temperature wear tester which could simulate actual hot rolling. The simulation test results revealed that the sticking process proceeded with three stages, i.e., nucleation, growth, and saturation. Since the hardness continuously decreased as the test temperature increased, whereas the formation of Fe-Cr oxides in the rolled steel surface region increased, the sticking of five stainless steels was evaluated by considering both the high-temperature hardness and oxidation effects. The addition of Zr, Cu, or Si had a beneficial effect on the sticking resistance, while the Ni addition did not show any difference in the sticking. Particularly in the case of the Si addition, Si oxides formed first in the initial stage of high-temperature oxidation, worked as initiation sites for Fe-Cr oxides, accelerated the formation of Fe-Cr oxides, and thus raised the sticking resistance by about 10 times in comparison with the steel without Si content

  18. Alternative Fabrication Routes toward Oxide-Dispersion-Strengthened Steels and Model Alloys

    Science.gov (United States)

    Bergner, Frank; Hilger, Isabell; Virta, Jouko; Lagerbom, Juha; Gerbeth, Gunter; Connolly, Sarah; Hong, Zuliang; Grant, Patrick S.; Weissgärber, Thomas

    2016-07-01

    The standard powder metallurgy (PM) route for the fabrication of oxide-dispersion-strengthened (ODS) steels involves gas atomization to produce a prealloyed powder, mechanical alloying (MA) with fine oxide powders, consolidation, and finally thermal/thermomechanical treatment (TMT). It is well established that ODS steels with superior property combinations, for example, creep and tensile strength, can be produced by this PM/MA route. However, the fabrication process is complex and expensive, and the fitness for scaling up to the industrial scale is limited. At the laboratory scale, production of small amounts of well-controlled model systems continues to be desirable for specific purposes, such as modeling-oriented experiments. Thus, from the laboratory to industrial application, there is growing interest in complementary or alternative fabrication routes for ODS steels and related model systems, which offer a different balance of cost, convenience, properties, and scalability. This article reviews the state of the art in ODS alloy fabrication and identifies promising new routes toward ODS steels. The PM/AM route for the fabrication of ODS steels is also described, as it is the current default process. Hybrid routes that comprise aspects of both the PM route and more radical liquid metal (LM) routes are suggested to be promising approaches for larger volumes and higher throughput of fabricated material. Although similar uniformity and refinement of the critical nanometer-sized oxide particles has not yet been demonstrated, ongoing innovations in the LM route are described, along with recent encouraging preliminary results for both extrinsic nano-oxide additions and intrinsic nano-oxide formation in variants of the LM route. Finally, physicochemical methods such as ion beam synthesis are shown to offer interesting perspectives for the fabrication of model systems. As well as literature sources, examples of progress in the authors' groups are also highlighted.

  19. Effects of temperature, dissolved oxygen and material factor on SCC behavior of low alloy steels in high temperature water

    International Nuclear Information System (INIS)

    Stress corrosion cracking (SCC) susceptibility of heavy-thick low alloy steels was investigated by slow strain rate tensile (SSRT) tests in high temperature water containing various levels of dissolved oxygen (DO) at temperature of 373 K to 593 K. Rolled steels with high sulfur content had SCC susceptibility in the wide region of temperature-DO concentration combination, even in DO<0.005 ppm at 473 K. A forged steel with extremely low sulfur content was almost immune to SCC. SCC maps as functions of temperature and DO concentration were proposed for each steel from the SSRT tests results. (author)

  20. Low-cycle fatigue properties of stainless steels and aluminum alloys at liquid helium temperature

    International Nuclear Information System (INIS)

    Axial-strain controlled fatigue tests of stainless steels (SUS 304 L, SUS 316 L and WM-X) and aluminum alloys (A 5083-O and A 5356) were conducted at 4 K with the strain rate of 0.4 %/s and the strain ratio of -1. The fatigue tests at 77 and 300 K were also conducted for comparison. The TIG weld metal of stainless steel (WM-X) showed cyclic strain-hardening at 4 and 77 K, and cyclic strain-softening at 300 K, although other materials showed cyclic strain-hardening at 4, 77 and 300 K. It seemed that the strain-induced martensitic transformation influenced the cyclic stress responce of stainless steel. In the fatigue life range of 1000 cycles or more, the fatigue resistance, that means the strain capability at given cycles of fatigue life, of SUS 304 L, SUS 316 L, WM-X and A 5083-O at 4 K were nearly equal to or a bit higher than that at 77 K. At 4 K, the fatigue resistance of SUS 316 L was higher than that of SUS 304 L, but lied in the middle of a scatter band by a factor of 2 among base metals of stainless steels in literatures. The fatigue resistance of A 5083-O was the lowest in a scatter band by a factor of 1.4 among base metals of aluminum alloys in literatures. At 4 K, the fatigue resistance of WM-X was almost equivalent to that of SUS 304 L and was lower than that of SUS 316 L by 20 %, being away below that of base metals of stainless steels at 300 K. However, the fatigue resistance of the MIG weld metal of aluminum alloy (A 5356) was lower than that of A 5083-O by 45 %, being closer to that of base metals of aluminum alloy at 300 K. One must be careful to use the weld metal A 5356 at 4 K. (author)

  1. Effect of alloying elements on the electronic properties of thin passive films formed on carbon steel, ferritic and austenitic stainless steels in a highly concentrated LiBr solution

    International Nuclear Information System (INIS)

    The influence of alloying elements on the electrochemical and semiconducting properties of thin passive films formed on several steels (carbon steel, ferritic and austenitic stainless steels) has been studied in a highly concentrated lithium bromide (LiBr) solution at 25 °C, by means of potentiodynamic tests and Mott–Schottky analysis. The addition of Cr to carbon steel promoted the formation of a p-type semiconducting region in the passive film. A high Ni content modified the electronic behaviour of highly alloyed austenitic stainless steels. Mo did not modify the electronic structure of the passive films, but reduced the concentration of defects. - Highlights: • The addition of Cr to carbon steel promotes p-type semiconductivity. • Passive films formed on stainless steels are made up of complex spinel oxides. • Ni modifies the electronic behaviour of highly alloyed austenitic stainless steels

  2. Ductile-to-brittle transition in a low alloy steel

    International Nuclear Information System (INIS)

    The mechanical properties of pressure vessel steel (and above all its resistance to brittle fracture) are a decisive factor in the complex safety assessment of nuclear power plants. The monitoring of neutron induced embrittlement is provided using Charpy impact tests on standard V-notch specimens due to their small size. Material's ductile-to-brittle transition temperature (DBTT) can be easily characterised using this test. However, Charpy impact energy cannot be immediately used for safety assessment, since fracture toughness is required. Some empirical formulas have been developed, but no direct relationship was still found. When the specimens are tested in the ductile-to-brittle transition region, cleavage crack initiation is preceded by ductile crack growth giving a large scatter to the values of fracture toughness and/or Charpy impact energy. Even if the cleavage initiation and propagation in steels containing isolated spheroidic carbides are qualitatively well understood, no one from existing models can explain the sharp upturn in ductile-to-brittle transition region. In the present work, French tempered bainitic steel 16MND5 (considered as equivalent to the American standard A508 Cl.3) is studied: The large fractographic analysis of CT and Charpy specimens broken in the DBTT range is undertaken to account for the evolution of cleavage fracture mechanisms. In addition to classical scanning electron microscopy, transmission electron microscopy and EBSD technique are used in order to study the propagation of cleavage crack. The classical fracture mechanics using KIc or Jc concepts can hardly describe the unstable brittle fracture in the DBTT range. Hence, the local approach, which aims to predict the fracture of any structural component using local criteria, providing that the mechanical fields in the structure are known, is used. The probability of cleavage fracture in the DBTT range is predicted using the Beremin model based on weakest link theory, e.g. 2

  3. Effect of inter-critical quenching on mechanical properties of casting low-alloy steel

    Directory of Open Access Journals (Sweden)

    Liu Zhongli

    2013-07-01

    Full Text Available For some casting low-alloy steels, traditional quenching and tempering heat treatments can improve the strength; however, sometimes the ductility is not satisfied. Therefore, some kind of effective heat treatment method seems necessary; one which could improve the ductility, but not seriously affect the strength. In this paper, the effect of inter-critical quenching (IQ on the mechanical properties of casting low-alloy steel was studied. IQ was added between quenching and tempering heat treatment; and the microstructure and mechanical properties were compared to the same steel with the traditional quenching and tempering treatments. The experimental results show that the microstructure comprises small-size ferrite and martensite when the IQ is adopted; and that different temperatures can control the ferrite quantity and distribution, and, as a result, influence the mechanical properties. In the case of IQ, the tensile strength decreases just a little, but the ductility increases a lot; and the strength-ductility product (its value is the arithmetic product of elongation and tensile strength increases by between 6% and 10%, which means the IQ heat treatment can improve comprehensive mechanical properties.

  4. Study of electroless Ni-W-P alloy coating on martensitic stainless steel

    Science.gov (United States)

    Nikitasari, Arini; Mabruri, Efendi

    2016-04-01

    Electroless nickel phospor (Ni-P) is widely used in many industries due to their corrosion and wear resistance, coating uniformity, and ability to coat non-conductive surfaces. The unique properties of tungsten such as high hardness, higher melting point, lower coefficient of linear thermal expansion, and high tensile strength have created a lot of interest in developing ternary Ni-W-P alloys. This article presents the study of electroless Ni-W-P alloys coating using acid or alkaline bath on martensitic stainless steel. Nickel sulfate and sodium tungstate were used as nickel and tungsten sources, respectively, and sodium hypophosphite was used as a reducing agent. Acid or alkaline bath refer to bath pH condition was adjusted by adding sulfuric acid. Martensitic stainless steel was immersed in Ni-W-P bath for 15, 30, and 60 minutes. The substrate of martensitic stainless steel was subjected to pre-treatment (polishing and cleaning) and activation prior to electroless plating. The plating characteristics were investigated for concentration ratio of nickel and hypophosphite (1:3), sodium tungstate concentration 0,1 M, immersion time (15 min, 30 min, 60 min), and bath condition (acid, alkaline). The electroless Ni-W-P plating was heat treated at 400°C for 1 hour. Deposits were characterized using scanning electron microscope (SEM) and corrosion measurement system (CMS).

  5. Analysis of micro-mechanical properties and microstructure of low-alloy steel using indentation technique

    International Nuclear Information System (INIS)

    Low alloy steels for nuclear reactor are degraded progressively through microstructural changes due to high operation temperature and irradiation. Strength properties are the most important factors for the selection of materials and the determination of degradation degree. Interfacial properties affected by strengthening particles with the range of nm size and strength distribution in microstructures could not be tested by the conventional mechanical testing methods. Microindentation and nanoindentation technique have been studied as a alternative of conventional methods. Specially, nanoindentation technique with a μN load range and a nm residual indent size range has been highlightened as a tool which is very useful to determine those properties. Since each phase composing microstructure of steels has a characteristic hardness value, it is possible to characterize phase on the basis of that character. In this study, by using of microindentation and nanoindentation technique can be evaluated microstructural mechanical properties of low alloy steels manufactured under 7 different kinds of processes. Through the study, we verified potentialities whether or not indentation technique can be used as a method to determine degree of degradation

  6. Welding of thin sheets of high strength zinc alloy coated steels

    International Nuclear Information System (INIS)

    Zinc alloy coated, high strength (G550) sheet steels are important materials in automobile manufacture, building and construction. Spot or arc welding is typically required in the component manufacturing process, but these processes result in localised softening because of the weld thermal cycle. As a consequence, the strength is normally downgraded significantly for design purposes to values typical of the annealed Zn or Zn alloy grades (G250 or G300). The investigation described in this paper involved the examination of the effect of the welding process and welding variables on butt welding on 1mm thick Zn-coated and Zn-Al-coated sheet steels. It has been demonstrated that these sheet steels can be successfully welded by both FCAW and GMAW methods using appropriately low welding heat inputs. However, strength loss below the minimum specified 5.50 MPa tensile strength did occur because of transformation and recrystallisation of the recovery annealed base metal structure as a result of the heat input of the welding process. The extent of the strength loss increased with increasing nominal weld heat input due to an increased width of the softened heat affected zone (HAZ) regions and grain growth in the grain refined and recrystallised regions. The maximum loss in yield strength at the highest heat input of 130 J/mm was about 150 MPa, suggesting that a minimum yield stress of 400 MPa can be safely used for structural design calculations.

  7. Thermal Diffusivity and Thermal Conductivity of Five Different Steel Alloys in the Solid and Liquid Phases

    Science.gov (United States)

    Wilthan, B.; Schützenhöfer, W.; Pottlacher, G.

    2015-08-01

    The need for characterization of thermophysical properties of steel and nickel-based alloys was addressed in the FFG-Bridge Project 810999 in cooperation with a partner from industry, Böhler Edelstahl GmbH & Co KG. To optimize numerical simulations of production processes, such as remelting or plastic deformation, additional, and more accurate data were necessary for the alloys under investigation. With a fast ohmic pulse heating circuit system, the temperature-dependent specific electrical resistivity, density, and specific heat capacity for a set of five high alloyed steels were measured. Hence, using the Wiedemann-Franz law with a Lorenz number of , the thermal diffusivity and thermal conductivity could be calculated for the solid and liquid phases up to temperatures of 2500 K. This experimental approach is limited by the following requirements for the specimens: they have to be electrically conducting, the melting point has to be high enough for the implemented pyrometric temperature measurement, and one has to be able to draw wires of the material. The latter restriction is technologically challenging with some of the materials being very brittle. For all samples, electrical and temperature signals are recorded and a fast shadowgraph method is used to measure the volume expansion. For each material under investigation, a set of data including the chemical composition, the density at room temperature, solidus and liquidus temperatures, and the change of enthalpy, resistivity, density, thermal conductivity, and thermal diffusivity as a function of temperature is reported.

  8. Shake table tests and analytical simulations of a steel structure with shape memory alloy dampers

    International Nuclear Information System (INIS)

    This study uses the pseudoelastic properties of Ni–Ti shape memory alloy wires for attenuation of the seismic response of a steel structure and evaluates its effectiveness and applicability in seismic response control. In this paper, shake table tests, carried out on a model of a steel structure with and without wire-based shape memory alloy dampers, are discussed in detail. Shake table tests, comprised of free vibration tests and spectrum compatible time history tests, were carried out. The former were used for the evaluation of the frequency and damping, and the later were used to prove the efficacy of the shape memory alloy dampers. Further analytical simulations are carried out using detailed time history analysis utilizing a thermomechanical model of an SMA and taking into account the residual martensite accumulation, which is irreversibly due to cyclic forward/reverse martensitic transformation. Moreover, a simple iterative response spectrum (IRS) method with equivalent damping and stiffness is also used to evaluate the response of the structure with SMA dampers, and it is proved that the method can be conservatively used by designers. (paper)

  9. Wear characterization of a tool steel surface modified by melting and gaseous alloying

    International Nuclear Information System (INIS)

    Hot forging dies are subjected to laborious service conditions and so there is a need to explore means of improving die life to increase productivity and quality of forgings. Surface modification in order to produce wear resistant surface is an attractive method as it precludes the need to use expensive and highly alloyed steels. In this study, a novel, inexpensive surface modification technique is used to improve the tri biological properties of an H13 tool steel. Surface melting was achieved using a tungsten heat source and gaseous alloying produced under a shield of argon, carbon dioxide, carbon dioxide-argon mixture and nitrogen gases. The change in wear behaviour was compared through micro-hardness indentation measurements and using a dry sliding pin-on-plate wear testing machine. This study shows superior wear behaviour of the modified surfaces when compared to the untreated surfaces. The increase in wear resistance is attributed to the formation of carbides when surfaces are melted under a carbon dioxide shield. However, in the case of nitrogen and argon gaseous alloying, an increase in wear resistance can be attributed to an increase in surface hardness which in turn effects surface deformation behaviour. (author)

  10. Study of ultrasonically assisted turning of stainless steel and brass alloys

    International Nuclear Information System (INIS)

    Ultrasonically assisted turning (UAT) is a hybrid machining technique employing high-frequency small-amplitude vibration superimposed on the tool movement during turning. It is superior to conventional turning (CT) with regard to cutting forces, surface quality and machining accuracy. The aim of this study is to investigate the effect of different machining parameters on stainless steel and brass alloys, during both UAT and CT, and evaluate improvements of cutting forces, surface roughness, surface integrity, and machining accuracy. An experimental setup for UAT at Loughborough University was used to accomplish this investigation. This setup used a Picoscope data acquisition add-on with Kistler three-component dynamometer, Seco DNMG cutting inserts were utilized, a surface tester from Taylor Hobson was used to evaluate surface roughness, Alicona Infinite Focus microscope was used to evaluate surface roughness and surface integrity, while Metris CMM with Renishaw probe was employed to evaluate machining accuracy. Cylindrical workpieces of steel and brass alloys were turned under CT and UAT conditions; cutting forces, surface roughness, and machining accuracy produced with both techniques where compared. Significant improvements were noticed in the ultrasonically assisted machining when compared to the CT for both alloys

  11. Effect of gradient thermal distribution on butt joining of magnesium alloy to steel with Cu–Zn alloy interlayer by hybrid laser–tungsten inert gas welding

    International Nuclear Information System (INIS)

    Highlights: ► The gradient thermal distribution is put forward to affect butt joining. ► Butt joining of Mg alloy to steel is realized by hybrid welding with interlayer. ► The joint fracture happens in the Mg weld seam instead of the Mg/Fe interface. ► Metallurgical bonding is achieved. ► The tensile strength attains 203 MPa. -- Abstract: Experimental investigations on butt welding of magnesium alloy to steel by hybrid laser–tungsten inert gas (TIG) welding with Cu–Zn alloy interlayer are carried out. The results show that the gradient thermal distribution of hybrid laser–TIG welding, controlled by offset adjustment, has a noticeable effect on mechanical properties and microstructure of the joints. Particularly, at the offset of 0.2 mm, defect-free joints are obtained, and the tensile strength could attain a maximum value of 203 MPa. Moreover, the fracture of the joint with the 0.2 mm offset happens in the weld seam of Mg alloy instead of the Mg/Fe interface. Owning to the addition of the Cu–Zn alloy interlayer, a metallurgical bonding between Mg alloy and steel is achieved based on the formation of intermetallic compounds of CuMgZn and solid solutions of Cu and Al in Fe. Meanwhile, the same element distribution tendency of Fe and Al indicates the intimate interaction between Fe and Al in current experimental conditions.

  12. A novel active fire protection approach for structural steel members using NiTi shape memory alloy

    International Nuclear Information System (INIS)

    A novel active fire protection approach, based on integrating a shape memory alloy, NiTi, with a steel structure, was proposed to satisfy the fire resistance requirements in structural design. To demonstrate the principles of this approach, a simple structure in the form of a simply supported steel beam was used. The internal action of the beam due to a transverse applied load was reduced by utilizing the shape memory effect in the NiTi alloy at rising temperatures. As a result, the net internal action from the load design was kept below the deteriorated load capacity of the beam during the fire scenario for period of time that was longer than that of the original beam without the NiTi alloy. By integrating the NiTi alloy into the beam system, the structure remained stable even though the steel temperature exceeded the critical temperature which may have caused the original beam structure to collapse. Prior to testing the composite NiTi–steel beam under simulated fire conditions, the NiTi alloy specimens were characterized at high temperatures. At 300 °C, the stiffness of the specimens increased by three times and its strength by four times over that at room temperature. The results obtained from the high-temperature characterization highlighted the great potential of the alloy being used in fire engineering applications. (paper)

  13. Formation Mechanism of Spinel-Type Inclusions in High-Alloyed Stainless Steel Melts

    Science.gov (United States)

    Park, Joo Hyun

    2007-08-01

    Fundamental thermodynamics of the relationship between high-alloyed stainless steel melts (Fe-20 mass pct Cr-13 mass pct Ni-3 mass pct Si) and the inclusions were investigated. The formation mechanism of the inclusions containing the spinel crystals was developed based on the experimental results and from the compositions of the inclusions in the steel samples taken during plant operations. The molar content of alumina in the inclusions was found to be linearly proportional to the increase of aluminum content, indicating that the inclusions could contain alumina even with less than about 200 ppm aluminum in the steel melt, e.g., steel melts that were mainly deoxidized by silicon. Furthermore, the composition of the inclusions is shown to be a function of the activity of the deoxidizers such as aluminum and silicon in the steel melt. From the analysis of the plant samples, it was found that the contents of MgO and Al2O3 in the calcium silicate type inclusions increased continuously as the steel melt transfers from the argon oxygen decarburization (AOD) converter to the tundish. This composition change in the inclusions originated from the reduction of MgO and Al2O3 in the slags or refractories by silicon in the steel melt. Increases of MgO and Al2O3 contents were prominent in tundish samples, and thus, the spinel phase could be crystallized in the calcium silicate inclusion matrix in the tundish; and finally the spinel crystals grew during cooling of the steel melt through the continuous casting (CC) mold and in the slabs. On the other hand, manganese silicate type inclusions containing chromium oxide were observed after tapping of the molten steel to the ladle. The MnO and Cr2O3 in these inclusions was initially reduced by silicon in the steel melt in the ladle treatment (LT) process, followed by further reduction by aluminum through the LT to the CC mold. The fractions of inclusions containing spinel crystals in cast slabs were negligible at the alumina content of

  14. Critical Aspects of Alloying of Sintered Steels with Manganese

    Science.gov (United States)

    Hryha, Eduard; Dudrova, Eva; Nyborg, Lars

    2010-11-01

    This study examines the sintering behavior and properties of Fe-0.8Mn-0.5C manganese powder metallurgy steels. The study focuses on the influence of mode of alloying—admixing using either high-purity electrolytic manganese or medium carbon ferromanganese as well as the fully prealloying of water-atomized powder. Three main aspects were studied during the whole sintering process—microstructure development, interparticle necks evolution, and changes in the behavior of manganese carrier particles during both heating and sintering stages. The prealloyed powder shows considerable improvement in carbon homogenization and interparticle neck development in comparison with admixed materials. The first indication of pearlite for the fully prealloyed material was registered at ~1013 K (740 °C) in comparison with ~1098 K (825 °C) in the case of the admixed systems. The negative effect of the oxidized residuals of manganese carrier particles and high microstructure inhomogeneity, which is a characteristic feature of admixed systems, is reflected in the lower values of the mechanical properties. The worst results in this respect were obtained for the system admixed with electrolytic manganese because of more intensive manganese sublimation and resulting oxidation at lower temperatures. According to the results of X-ray photoelectron spectroscopy and high-resolution scanning electron microscopy and energy dispersive X-ray analyses, the observed high brittleness of admixed materials is connected with intergranular decohesion failure associated with manganese oxide formation on the grain boundaries.

  15. Changes of inclusion, texture and magnetic property of non-oriented Si steel treated by Ca alloy

    Science.gov (United States)

    Lv, X.; Zhang, F.; Chen, X.

    2015-04-01

    Based on the industrial production of non-oriented Si steel, Ca treatment by Ca alloy adding during the RH refining process was studied. The changes of inclusion, crystal texture and microstructure, and its effect on magnetic properties of final steel sheets were analyzed. The results showed that, in present work, Ca treatment can improve the texture proportion of {110} and {111} significantly, and the formation of MnS and AlN inclusions were restrained. Meanwhile, the recrystallization effects of hot rolled strip get bad and the fiber structure enhanced obviously. The grain size of finished steel sheets increased as the increase of Ca alloy adding amount quickly, and then decreased. Compared with the non-Ca treatment charge, the numbers of inclusions whose size below 1.0μm will decrease by 68.06%, 87.50% and 94.94%, the texture proportion of {110} and {111} was 30.3%, 39.1%, 17.6% and 2.8%, 5.5%, 20.6%, while the correspondent Ca alloy adding amount is 0.67 kg/t steel, 1.00 kg/t steel and 1.67 kg/t steel, respectively. In addition, the core loss gradually decreases to a stable level as the increasing of Ca added, and the magnetic induction decreases quickly after slow increasing, respectively. The optimal Ca treatment mode depends on the chemical compositions of steel grades.

  16. Effect of antimony on the corrosion behavior of low-alloy steel for flue gas desulfurization system

    International Nuclear Information System (INIS)

    The alloying effect of Sb in a new low-alloy steel for the purpose of FGD materials was investigated by potentiodynamic polarization, linear polarization resistance measurement, electrochemical impedance spectroscopy (EIS) and weight loss measurements in an aggressive solution of 16.9 vol.% H2SO4 + 0.35 vol.% HCl (modified green death solution) at 60 deg. C, pH -0.3. All measurements confirmed the marked improvement in the corrosion behavior of the low-alloy steel via the addition of a small amount of Sb, particularly for the 0.10Sb steel. Pitting corrosion was detected by scanning electron microscopy (SEM) on the surface of blank steel and 0.05Sb steel, but not 0.10Sb steel, after weight loss measurements. X-ray photoelectron spectroscopy (XPS) analysis of the corroded surfaces after EIS and linear polarization measurements showed that the decrease in corrosion rates was due to the formation of a protective Sb2O5 oxide film on the surface of the Sb-containing steels. Moreover, the addition of 0.10% Sb stimulated the development of high corrosion inhibiting, Cu-containing compounds which further inhibited the anodic and cathodic reactions

  17. Tensile and pack compressive tests of some sheets of aluminum alloy, 1025 carbon steel, and chromium-nickel steel

    Science.gov (United States)

    Atchison, C S; Miller, James A

    1942-01-01

    Tensile and compressive stress-strain curves, stress-deviation curves, and secant modulus-stress curves are given for longitudinal and transverse specimens of 17S-T, 24S-T, and 24S-RT aluminum-alloy sheet in thicknesses from 0.032 to 0.081 inch, 1025 carbon steel sheet in thicknesses of 0.054 and 0.120 inch, and chromium-nickel steel sheet in thicknesses form 0.020 to 0.0275 inch. Significant differences were found between the tensile and the compressive stress-strain curves, and also the corresponding corollary curves; similarly, differences were found between the curves for the longitudinal and transverse directions. These differences are of particular importance in considering the compressive strength of aircraft structures made of thin sheet. They are explored further for the case of compression by giving tangent modulus-stress curves in longitudinal and transverse compression and dimensionless curves of the ratio of tangent modulus to Young's modulus and of the ratio of reduced modulus for a rectangular section to Young's modulus, both plotted against the ratio of stress to secant yield strength.

  18. Influence of heat input on weld bead geometry using duplex stainless steel wire electrode on low alloy steel specimens

    Directory of Open Access Journals (Sweden)

    Ajit Mondal

    2016-12-01

    Full Text Available Gas metal arc welding cladding becomes a popular surfacing technique in many modern industries as it enhances effectively corrosion resistance property and wear resistance property of structural members. Quality of weld cladding may be enhanced by controlling process parameters. If bead formation is found acceptable, cladding is also expected to be good. Weld bead characteristics are often assessed by bead geometry, and it is mainly influenced by heat input. In this paper, duplex stainless steel E2209 T01 is deposited on E250 low alloy steel specimens with 100% CO2 gas as shielding medium with different heats. Weld bead width, height of reinforcement and depth of penetration are measured. Regression analysis is done on the basis of experimental data. Results reveal that within the range of bead-on-plate welding experiments done, parameters of welding geometry are on the whole linearly related with heat input. A condition corresponding to 0.744 kJ/mm heat input is recommended to be used for weld cladding in practice.

  19. Surface Modification of Micro-Alloyed High-Strength Low-Alloy Steel by Controlled TIG Arcing Process

    Science.gov (United States)

    Ghosh, P. K.; Kumar, Ravindra

    2015-02-01

    Surface modification of micro-alloyed HSLA steel plate has been carried out by autogenous conventional and pulse current tungsten inert gas arcing (TIGA) processes at different welding parameters while the energy input was kept constant. At a given energy input the influence of pulse parameters on the characteristics of surface modification has been studied in case of employing single and multi-run procedure. The role of pulse parameters has been studied by considering their summarized influence defined by a factor Φ. The variation in Φ and pulse frequency has been found to significantly affect the thermal behavior of fusion and accordingly the width and penetration of the modified region along with its microstructure, hardness and wear characteristics. It is found that pulsed TIGA is relatively more advantageous over the conventional TIGA process, as it leads to higher hardness, improved wear resistance, and a better control over surface characteristics.

  20. High Power Laser Welding. [of stainless steel and titanium alloy structures

    Science.gov (United States)

    Banas, C. M.

    1972-01-01

    A review of recent developments in high power, carbon dixoide laser welding is presented. Deep penetration welding in stainless steel to 0.5-in. thick, high speed welding in thin gage rimmed steel and gas shielded welding in Ti-6Al-4V alloy are described. The effects of laser power, power density, focusing optics, gas-shielding techniques, material properties and weld speed on weld quality and penetration are discussed. It is shown that laser welding performance in thin materials is comparable to that of electron beams. It is further shown that high quality welds, as evidenced by NDT, mechanical and metal-lographic tests, can be achieved. The potential of the laser for industrial welding applications is indicated.

  1. Standard guide for estimating the atmospheric corrosion resistance of low-alloy steels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This guide presents two methods for estimating the atmospheric corrosion resistance of low-alloy weathering steels, such as those described in Specifications A242/A242M, A588/A588M, A606 Type 4, A709/A709M grades 50W, HPS 70W, and 100W, A852/A852M, and A871/A871M. One method gives an estimate of the long-term thickness loss of a steel at a specific site based on results of short-term tests. The other gives an estimate of relative corrosion resistance based on chemical composition. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  2. Dissimilar ultrasonic spot welding of Mg-Al and Mg-high strength low alloy steel

    Directory of Open Access Journals (Sweden)

    V.K. Patel

    2014-01-01

    Full Text Available Sound dissimilar lap joints were achieved via ultrasonic spot welding (USW, which is a solid-state joining technique. The addition of Sn interlayer during USW effectively blocked the formation of brittle al12Mg17 intermetallic compound in the Mg-Al dissimilar joints without interlayer, and led to the presence of a distinctive composite-like Sn and Mg2Sn eutectic structure in both Mg-Al and Mg-high strength low alloy (HSLA steel joints. The lap shear strength of both types of dissimilar joints with a Sn interlayer was significantly higher than that of the corresponding dissimilar joints without interlayer. Failure during the tensile lap shear tests occurred mainly in the mode of cohesive failure in the Mg-Al dissimilar joints and in the mode of partial cohesive failure and partial nugget pull-out in the Mg-HSLA steel dissimilar joints.

  3. Fine structure and resistance to fracture of low-alloyed steel with vanadium and boron

    International Nuclear Information System (INIS)

    An attempt to evaluate the effect of recovery recrystallization and precipitation processes of dispersion phases on the nature of heat-treating steel resistance to fracture is made. A low-alloy steel of industrial melting with the following content of components, weight %: C-0.18; Mn-1.4; Si-0.3; V-0.06; B-0.003; Al-0.04 and Ti-0.015 has been chosen. It is shown that vanadium carbide precipitation during tempering essentially contributes to the weakening processes. The main contribution to strength is made by the most dispersive carbide phase with the dimensions less than 0.03 mkm delaying weakening during tempering

  4. Dynamic deformation and fragmentation response of maraging steel linear cellular alloy

    Science.gov (United States)

    Jakus, Adam E.; Fredenberg, David A.; McCoy, Tammy; Thadhani, Naresh; Cochran, Joe K.

    2012-03-01

    The dynamic deformation and fragmentation response of 25% dense 9-cell linear cellular alloy (LCA) made of unaged 250 maraging steel, fabricated using a direct reduction and extrusion technique, is investigated. Explicit finite element simulations were implemented using AUTODYN finite element code. The maraging steel properties were defined using a Johnson-Cook strength model with previously validated parameters. Rod-on-anvil impact tests were performed using the 7.6mm helium gas gun and the transient deformation and fragmentation response was recorded with highspeed imaging. Analysis of observed deformation states of specimens and finite element simulations reveal that in the case of the 9-cell LCA, dissipation of stress and strain occurs along the interior cell wells resulting in significant and ubiquitous buckling prior to confined fragmentation.

  5. Oxidation behavior of nickel-base superalloys and High Strength Low Alloy (HSLA) steels at elevated temperatures

    Science.gov (United States)

    Talekar, Anjali S.

    Alloy C-22 (UNS N06022) and High Strength Low Alloy (HSLA) steels are candidate materials for use in outer layer of waste storage packages and as rock bolts in the underground roof supports at Yucca Mountain nuclear waste repository respectively. Oxidation kinetics of three Ni-base Superalloys and two HSLA Steels, Split Set Friction Rock Stabilizers (SS-46) and Swellex Mn-24, have been determined by isothermal high temperature continuous measurement thermogravimetry at temperatures ranging between 600°C to 1100°C in pure oxygen atmosphere for predetermined periods of exposures (48 hours for the Superalloys and 100 hours for HSLA steels). The two other Ni-base Superalloys selected were Alloy-263 (UNS N07263) and Alloy-282. These are similar in their Cr composition to Alloy C-22 and have variations in the contents of other alloying elements namely Co and Mo. The alloys were selected for comparison of their oxidation resistance with C-22 as a baseline material. All three Superalloys are known chromia formers. All the superalloys were evaluated for determining their kinetic parameters and the activation energies for the superalloys were also calculated. The activation energy for the parabolic regime of Alloy-282 is found to be 232 kJ/mol. The slope of the curves on a plot of kp as a function of (1/T) show Alloy-282 to have better oxidation resistance up to 980°C and thereafter the rate constants are similar for all three alloys, but when activation energies over the whole temperature range are calculated, Alloy-263 shows the best average oxidation resistance. Surface characterization by means of microscopy as well as X-ray photoelectron spectroscopy showed the nature of oxides formed. Based on the kinetics and the characterization, proposed mechanisms for oxidation of these alloys at high temperatures are put forth. Temperature modulated thermogravimetry was used for studies on HSLA steels. The imposed sinusoidal temperature modulations on the isothermal temperature

  6. Influence of zirconium on microstructure and toughness of low-alloy steel weld metals

    Science.gov (United States)

    Trindade, V. B.; Mello, R. S. T.; Payão, J. C.; Paranhos, R. P. R.

    2006-06-01

    The influence of zirconium on microstructure and toughness of low-alloy steel weld metal was studied. Weld metals with different zirconium contents were obtained adding iron-zirconium alloy in the welding flux formulation. Weld metal chemical composition proved that zirconium was able to be transferred from the flux to the weld metal. The addition of zirconium refined the weld metal microstructure, increasing the acicular ferrite content. Weld metal toughness, determined by means of impact Charpy-V tests, showed that the zirconium addition is beneficial up to a content of 0.005 wt.%. Above this level, zirconium was not able to produce further microstructure refinement, although the toughness was reduced, possibly due to the formation of microconstituent such as the martensite-austenite constituent (M-A), which is considered to be deleterious to the weld metal toughness.

  7. Excimer laser processing of tool steel: Tribological effects of multiple pulse processing and titanium alloying

    Energy Technology Data Exchange (ETDEWEB)

    Jervis, T.R.; Nastasi, M.; Griffin, A.J. Jr.; Zocco, T.G.; Taylor, T.N.; Foltyn, S.R.

    1995-12-01

    Excimer lasers were used to modify the surface of AISI type A-7 tool steel, a high C, high V, high Cr material used in many cutting applications. Multiple pulses of laser radiation at 248 nm were used to alter the composition of the surface alloy. Hardness and modulus were not significantly affected by the treatment, but friction in dry sliding against an alumina pin was reduced. The reduction was small but persistent for multiply melted and resolidified surfaces. These surfaces showed a marked increase in the surface Cr concentration. Greater reductions in friction were obtained from a Ti rich surface layer formed by laser mixing an evaporated Ti layer into the material. The friction coefficient of the Ti alloyed surface deteriorated after approximately 1000 cycles, indicating wear=through of the modified surface. The observed properties will be discussed in terms of the excimer laser modification process and the microstructure and composition of the resulting surfaces.

  8. Spark Plasma Sintering of Low Alloy Steel Modified with Silicon Carbide

    Directory of Open Access Journals (Sweden)

    Hebda M.

    2016-06-01

    Full Text Available The influence of adding different amounts of silicon carbide on the properties (density, transverse rupture strength, microhardness and corrosion resistance and microstructure of low alloy steel was investigated. Samples were prepared by mechanical alloying (MA process and sintered by spark plasma sintering (SPS technique. After the SPS process, half of each of obtained samples was heat-treated in a vacuum furnace. The results show that the high-density materials have been achieved. Homogeneous and fine microstructure was obtained. The heat treatment that followed the SPS process resulted in an increase in the mechanical and plastic properties of samples with the addition 1wt. % of silicon carbide. The investigated compositions containing 1 wt.% of SiC had better corrosion resistance than samples with 3 wt.% of silicon carbide addition. Moreover, corrosion resistance of the samples with 1 wt.% of SiC can further be improved by applying heat treatment.

  9. Microstructural and mechanical characteristics of laser deposited Ni-Mo-Cr-Si alloy on stainless steel

    International Nuclear Information System (INIS)

    Microstructural characterization is important for controlling the quality of the laser cladding as well as to understand the metallurgical interaction between the substrate and the clad. Ni-Mo-Cr-Si alloy coatings deposited on stainless steel 316L substrate using laser cladding process were extensively characterized for microstructural, microchemical and micromechanical properties of the coating cross section using optical microscopy, scanning electron and transmission electron microscopy, chemical analysis (EDS microanalysis), microhardness and nanoindentation technique. Variation in solidification rate, cooling rate and compositional variation resulted in the heterogeneous microstructure. Different solidification morphology were seen in the clad cross section. Majority of the region was found to consist of eutectic of molybdenum and silicon rich intermetallic phase and nickel rich fcc solid solution phases. The observed changes in microstructure, microchemistry and hardness have been understood based on the phase transitions of the Ni-Mo-Cr alloy during solidification and cooling on the substrate. (author)

  10. Dynamic strain ageing of deformed nitrogen-alloyed AISI 316 stainless steels

    International Nuclear Information System (INIS)

    Intergranular stress corrosion cracking has occurred in BWR environment in non-sensitized, deformed austenitic stainless steel materials. The affecting parameters are so far not fully known, but deformation mechanisms may be decisive. The effect of deformation and nitrogen content on the behaviour of austenitic stainless steels was investigated. The materials were austenitic stainless steels of AISI 316L type with different amounts of nitrogen (0.03 - 0.18%) and they were mechanically deformed 0, 5 and 20%. The investigations are focused on the dynamic strain ageing (DSA) behaviour. A few crack growth rate measurements are performed on nuclear grade AISI 316NG material with different degrees of deformation (0, 5 and 20%). The effects of DSA on mechanical properties of these materials are evaluated based on peaks in ultimate tensile strength and strain hardening coefficient and minimum in ductility in the DSA temperature range. Additionally, internal friction measurements have been performed in the temperature range of -100 to 600 deg. C for determining nitrogen interactions with other alloying elements and dislocations (cold-worked samples). The results show an effect of nitrogen on the stainless steel behaviour, e.g. clear indications of dynamic strain ageing and changes in the internal friction peaks as a function of nitrogen content and amount of deformation. (authors)

  11. Characterization of microstructure obtained by quenching and partitioning process in low alloy martensitic steel

    International Nuclear Information System (INIS)

    Microstructure of low alloy martensitic steel treated by quenching and partitioning (Q and P) process was characterized by means of SEM, TEM, EBSD and XRD. Mechanical properties of steel processed by Q and P and the same steel processed by quenching and tempering (Q and T) were measured by uniaxial tensile test. The study suggests that microstructure is mainly composed of three phases, i.e. initial martensite, fresh martensite and retained austenite. The initial martensite formed at the first quenching step is easily etched; the fresh martensite is formed at the final quenching step and looks like 'blocky' type phase with size about 0.2-3 μm, and the retained austenite is mainly located on the packet boundary and initial austenite grain boundary. The measured volume fractions and carbon contents of these phases were slightly different from those predicted by the constrained paraequilibrium (CPE) model proposed by Speer, which was interpreted by the effects of the different grain sizes of the untransformed austenite after first quenching. Mechanical properties of steels processed by Q and P assume much higher strength and ductility than those processed by Q and T. It is concluded that Q and P process is a promising approach to control the multiphase structure with hard matrix and a ductile retained austenite, which gives an excellent combination of strength and ductility.

  12. 'FOURCRACK' - An investigation of the creep performance of advanced high alloy steel welds

    International Nuclear Information System (INIS)

    Creep failure by 'Type IV' cracking in the weld heat-affected zone (HAZ) is likely to be the life-limiting failure mechanism in high-alloy steel components for advanced power plant. A UK collaborative project, 'FOURCRACK', has therefore been carried out to investigate and compare the cross-weld creep rupture performance of several casts of the advanced steels E911, P92, and P122, and the established steel P91. The experimental matrix included both stress and temperature variations while minimising the testing required to characterise the comparative performance of different welded materials. The results clarify the interplay between weld metal and HAZ failure mechanisms, the relationships between parent material and cross-weld creep strength, and the relative merits of the alternative steels. Finally, problems which arise in the assessment of cross-weld creep test data are discussed, and recommendations put forward to address the risks of biased assessment when failure can take place in different locations within the weldment

  13. Effect of mechanical alloying parameters on irradiation damage in oxide dispersion strengthened ferritic steels

    International Nuclear Information System (INIS)

    Issues for developing oxide dispersion strengthened (ODS) steel are anisotropic mechanical properties due to the bamboo-like structure, impurity pick up during the mechanical alloying (MA) process, stability of oxide particles, heat-treatment condition and chemical composition. Several ODS steels were fabricated with a changing gas environment during MA, heat-treatment condition and chemical composition, and were electron-irradiated to 12 dpa at 673-748 K in a high-voltage electron microscope. An ODS martensitic steel (M-Ar) with high dislocation density showed very good swelling resistance. Swelling levels of ODS ferritic steels depended on the gas environment during MA and the recrystallization condition. These indicated that a helium gas environment during MA was more effective to suppress swelling than an argon gas environment and that cold working after recrystallization reduced void formation and swelling. The effect of MA parameters, such as the gas environment, heat-treat condition and cold working on the swelling behavior was evaluated

  14. Dynamic strain ageing of deformed nitrogen-alloyed AISI 316 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Ehrnsten, U.; Toivonen, A. [Materials and Structural Integrity, VTT Technical Research Centre of Finland, Kemistintie 3, P.O. Box 1704, FIN-02044 VTT (Finland); Ivanchenko, M.; Nevdacha, V.; Yagozinskyy, Y.; Haenninen, H. [Department of Mechanical Engineering, Helsinki University of Technology Puumiehenkuja 3, P.O. Box 4200, FIN-02015 HUT (Finland)

    2004-07-01

    Intergranular stress corrosion cracking has occurred in BWR environment in non-sensitized, deformed austenitic stainless steel materials. The affecting parameters are so far not fully known, but deformation mechanisms may be decisive. The effect of deformation and nitrogen content on the behaviour of austenitic stainless steels was investigated. The materials were austenitic stainless steels of AISI 316L type with different amounts of nitrogen (0.03 - 0.18%) and they were mechanically deformed 0, 5 and 20%. The investigations are focused on the dynamic strain ageing (DSA) behaviour. A few crack growth rate measurements are performed on nuclear grade AISI 316NG material with different degrees of deformation (0, 5 and 20%). The effects of DSA on mechanical properties of these materials are evaluated based on peaks in ultimate tensile strength and strain hardening coefficient and minimum in ductility in the DSA temperature range. Additionally, internal friction measurements have been performed in the temperature range of -100 to 600 deg. C for determining nitrogen interactions with other alloying elements and dislocations (cold-worked samples). The results show an effect of nitrogen on the stainless steel behaviour, e.g. clear indications of dynamic strain ageing and changes in the internal friction peaks as a function of nitrogen content and amount of deformation. (authors)

  15. Improvement of Laser Deposited High Alloyed Powder Metallurgical Tool Steel by a Post-tempering Treatment

    Science.gov (United States)

    Leunda, J.; Navas, V. García; Soriano, C.; Sanz, C.

    Laser cladding process of a high alloyed powder metallurgical tool steel was studied for die repairing purposes. The low hardness obtained after the deposition process was improved by later tempering cycles, achieving crack free coatings with hardness well above 700 HV. The effect of different post tempering cycles was investigated in order to determine the optimal temperature range. The microstructure of the samples was studied using optical and scanning electron microscope and the volumetric ratio of retained austenite was determined by X-ray diffraction. The tempering effect was mainly evaluated through cross-section microhardness profiles.

  16. Inertia and friction welding of aluminum alloy 1100 to type 316 stainless steel

    International Nuclear Information System (INIS)

    The inertia and friction-welding processes were evaluated for joining aluminum alloy 1100-H14 and Type 316 vacuum-induction melted, vacuum-arc remelted (VIM VAR) stainless steel. While both processes consistently produced joints in which the strength exceeded the strength of the aluminum base metal, 100 percent bonding was not reliably achieved with inertia welding. The deficiency points out the need for development of nondestructive testing techniques for this type of joint. Additionally, solid-state volume diffusion did not appear to be a satisfactory explanation for the inertia and friction-welding bonding mechanism

  17. Stress corrosion cracking of carbon and low alloy steels in high temperature water

    International Nuclear Information System (INIS)

    A new set of fracture mechanics stress corrosion crack growth rate data is presented for transgranular cracking of carbon and low alloy steels exposed to high temperature water. The essential observations are as follows. Fast stress corrosion crack growth rates between 10-9 and 10-8 m/s may be observed down to 400 ppb dissolved oxygen at water conductivities of 0.5 microS/cm in refreshed autoclaves. There is no effect of specimen thickness on the stress corrosion crack growth rates. Temperature, however, clearly is a major influential parameter on stress corrosion cracking

  18. The effects of dynamic load on behaviour of welded joint A-387 Gr. 11 alloyed steel

    Directory of Open Access Journals (Sweden)

    O. Popović

    2013-01-01

    Full Text Available The in-service behaviour of alloyed steel A-387 Gr. 11 Class 1, for pressure vessels, used for high temperature applications, depends on the properties of its welded joint, with parent metal (BM, heat-affected-zone (HAZ and weld metal (WM, as constituents. Charpy testing of BM, WM and HAZ, together with, determination of the parameters of fatigue-crack growth and fatigue threshold ΔKth was used, in order to understand, how heterogeneity of structure and different mechanical properties of welded joint constituents affect on crack initiation and propagation.

  19. Effects of heat treatment on properties of multi-element low alloy wear-resistant steel

    Directory of Open Access Journals (Sweden)

    SONG Xu-ding

    2007-02-01

    Full Text Available The paper has studied the mechanical properties and heat treatment effects on multi-element low alloy wear-resistant steel (MLAWS used as a material for the liner of rolling mill torii. The results show that when quenched at 900-920℃ and tempered at 350-370℃, the MLAWS has achieved hardness above 60 HRC, tensile strength greater than 1 600 MPa, impact toughness higher than 18J/cm2 and fracture toughness greater than 37 MPa

  20. Effect of Nitrogen Partitioning on Yield Strength in Nitrogen-Alloyed Duplex Stainless Steel During Annealing

    Science.gov (United States)

    Jang, Min-Ho; Moon, Joonoh; Lee, Tae-Ho; Park, Seong-Jun; Han, Heung Nam

    2014-04-01

    Nitrogen partitioning and its effect on the yield strength in nitrogen-alloyed duplex stainless steel during annealing were investigated at different annealing temperatures. The decrease in the austenite fraction with an increase in the annealing temperature promoted nitrogen partitioning into austenite. When the nitrogen content in austenite was low, the yield strength decreased with an increase in the annealing temperature due to grain growth, while when it was higher than 0.5 wt pct, the yield strength increased with an increase in the annealing temperature, because the austenite became noticeably hard.

  1. Some microstructural characterisations in a friction stir welded oxide dispersion strengthened ferritic steel alloy

    International Nuclear Information System (INIS)

    The goal of this study is to characterize microstructure of a friction stir welded oxide dispersion strengthened alloy. The welded material is constituted by two sheets of an yttria-dispersion-strengthened PM 2000 ferritic steel. Different areas of the friction stir welded product were analyzed using field emission gun secondary electron microscopy (FEG-SEM) and electron microprobe whereas nanoindentation was used to evaluate mechanical properties. The observed microstructural evolution, including distribution of the yttria dispersoids, after friction stir welding process is discussed and a correlation between the microstructure and the results of nanoindentation tests is established.

  2. Some microstructural characterisations in a friction stir welded oxide dispersion strengthened ferritic steel alloy

    Energy Technology Data Exchange (ETDEWEB)

    Legendre, F. [CEA Saclay, DEN/DANS/DMN/SRMP, 91191 Gif-sur-Yvette cedex (France)], E-mail: flegendre@cea.fr; Poissonnet, S.; Bonnaillie, P.; Boulanger, L. [CEA Saclay, DEN/DANS/DMN/SRMP, 91191 Gif-sur-Yvette cedex (France); Forest, L. [CEA Saclay, DEN/DANS/DM2S/SEMT/LTA, 91191 Gif-sur-Yvette cedex (France)

    2009-04-30

    The goal of this study is to characterize microstructure of a friction stir welded oxide dispersion strengthened alloy. The welded material is constituted by two sheets of an yttria-dispersion-strengthened PM 2000 ferritic steel. Different areas of the friction stir welded product were analyzed using field emission gun secondary electron microscopy (FEG-SEM) and electron microprobe whereas nanoindentation was used to evaluate mechanical properties. The observed microstructural evolution, including distribution of the yttria dispersoids, after friction stir welding process is discussed and a correlation between the microstructure and the results of nanoindentation tests is established.

  3. Some microstructural characterisations in a friction stir welded oxide dispersion strengthened ferritic steel alloy

    Science.gov (United States)

    Legendre, F.; Poissonnet, S.; Bonnaillie, P.; Boulanger, L.; Forest, L.

    2009-04-01

    The goal of this study is to characterize microstructure of a friction stir welded oxide dispersion strengthened alloy. The welded material is constituted by two sheets of an yttria-dispersion-strengthened PM 2000 ferritic steel. Different areas of the friction stir welded product were analyzed using field emission gun secondary electron microscopy (FEG-SEM) and electron microprobe whereas nanoindentation was used to evaluate mechanical properties. The observed microstructural evolution, including distribution of the yttria dispersoids, after friction stir welding process is discussed and a correlation between the microstructure and the results of nanoindentation tests is established.

  4. Dissimilar ultrasonic spot welding of Mg-Al and Mg-high strength low alloy steel

    OpenAIRE

    Patel, V K; D. L. Chen; S.D. Bhole

    2014-01-01

    Sound dissimilar lap joints were achieved via ultrasonic spot welding (USW), which is a solid-state joining technique. The addition of Sn interlayer during USW effectively blocked the formation of brittle al12Mg17 intermetallic compound in the Mg-Al dissimilar joints without interlayer, and led to the presence of a distinctive composite-like Sn and Mg2Sn eutectic structure in both Mg-Al and Mg-high strength low alloy (HSLA) steel joints. The lap shear strength of both types of dissimilar join...

  5. Dualism of precipitation morphology in high strength low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Chih-Yuan, Chen, E-mail: chen6563@gmail.com [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Chien-Chon, Chen [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Jer-Ren, Yang, E-mail: jryang@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2015-02-25

    While the role of microalloying elements on precipitation strengthening in ferrite matrix during austenite/ferrite transformation is quite clear, some uncertainty still exists concerning the variability of the microhardness distribution of ferrite grains in the isothermal holding condition. The objective of the present study was to clarify the intrinsic characteristics of carbide precipitation morphology in the ferrite matrix under different processing temperatures and times and to correlate it with austenite decomposition kinetics to elucidate why a large microhardness distribution occurs at low isothermal holding temperature. Better understanding of carbide precipitation behavior can help researchers to determine the root cause of variation in microhardness distribution, which would allow metallurgists to produce high quality steels. Measurement with a Vickers hardness indenter revealed that, in specimens isothermally held at 625 °C, the range of Vickers hardness distribution was 240–420 after 5 min of isothermal holding, and 270–340 after 60 min. For specimens isothermally held at 725 °C, the range of Vickers hardness distribution was 200–330 for 5 min of isothermal holding, and 200–250 for 60 min. Therefore, the average microhardness decreased with the isothermal holding temperature and time, and a larger range of distribution occurred with short isothermal holding times. Transmission electron microscopy (TEM) images showed that interface precipitation and random precipitation can occur within the same ferrite grain. The reason is that the austenite decomposition rate varies with transformation temperature and time. An excessively fast austenite/ferrite interface movement velocity, which usually happens in small ferrite grains, would cause these ferrite grains with microalloying elements to exceed their solubility. Furthermore, these microalloying elements will be precipitated randomly after isothermal holding at longer times. Consequently, a large

  6. Dualism of precipitation morphology in high strength low alloy steel

    International Nuclear Information System (INIS)

    While the role of microalloying elements on precipitation strengthening in ferrite matrix during austenite/ferrite transformation is quite clear, some uncertainty still exists concerning the variability of the microhardness distribution of ferrite grains in the isothermal holding condition. The objective of the present study was to clarify the intrinsic characteristics of carbide precipitation morphology in the ferrite matrix under different processing temperatures and times and to correlate it with austenite decomposition kinetics to elucidate why a large microhardness distribution occurs at low isothermal holding temperature. Better understanding of carbide precipitation behavior can help researchers to determine the root cause of variation in microhardness distribution, which would allow metallurgists to produce high quality steels. Measurement with a Vickers hardness indenter revealed that, in specimens isothermally held at 625 °C, the range of Vickers hardness distribution was 240–420 after 5 min of isothermal holding, and 270–340 after 60 min. For specimens isothermally held at 725 °C, the range of Vickers hardness distribution was 200–330 for 5 min of isothermal holding, and 200–250 for 60 min. Therefore, the average microhardness decreased with the isothermal holding temperature and time, and a larger range of distribution occurred with short isothermal holding times. Transmission electron microscopy (TEM) images showed that interface precipitation and random precipitation can occur within the same ferrite grain. The reason is that the austenite decomposition rate varies with transformation temperature and time. An excessively fast austenite/ferrite interface movement velocity, which usually happens in small ferrite grains, would cause these ferrite grains with microalloying elements to exceed their solubility. Furthermore, these microalloying elements will be precipitated randomly after isothermal holding at longer times. Consequently, a large

  7. Alloy Shrinkage factors for the investment casting of 17-4PH stainless steel parts

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, Adrian S [ORNL; Porter, Wallace D [ORNL

    2008-01-01

    In this study, the alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively. Dimensions of the die tooling, wax pattern, and casting were measured using a Coordinate Measurement Machine. For all the properties, the experimental data available in the literature did not cover the entire temperature range necessary for process simulation. A comparison between the predicted material property data measured property data is made. It was found that most material properties were accurately predicted over the most of the temperature range of the process. Several assumptions were made in order to obtain a complete set of mechanical property data at high temperatures. Thermal expansion measurements for the 17-4PH alloy were conducted at heating and cooling. As a function of temperature, the thermal expansion for both the alloy and shell mold materials showed different evolution at heating and cooling. Thus, one generic simulation were performed with thermal expansion obtained at heating and another one with thermal expansion obtained at cooling. The alloy dimensions were obtained from numerical simulation results of solidification, heat transfer, and deformation phenomena. As compared with experimental results, the numerical simulation results for the shrinkage factors were slightly over-predicted.

  8. X-ray photoelectron spectroscopy investigations of zinc-magnesium alloy coated steel

    Energy Technology Data Exchange (ETDEWEB)

    Chen Sheng, E-mail: chen_sheng@baosteel.com [Research Institute of Baoshan Iron and Steel Co. Ltd., 655 Fujin Road, Baoshan District, Shanghai 201900 (China); Yan Fei; Xue Fei; Yang Lihong; Liu Junliang [Research Institute of Baoshan Iron and Steel Co. Ltd., 655 Fujin Road, Baoshan District, Shanghai 201900 (China)

    2010-11-01

    The coating layer composition depth profiles and element chemical states of zinc-magnesium alloy coated steel were investigated by X-ray photoelectron spectroscopy depth profiling. Through the analysis of photoelectron signals and Auger signals of different elements on different depth planes of the coating layer, it can be found that the surface of the coating layer contains MgCO{sub 3}, MgO, Mg(OH){sub 2}, metallic Mg, metallic Zn and some complex zinc compounds. Under the surface, there is a Zn{sub 2}Mg alloy layer with the thickness of about 300 nm accompanied with MgO and Mg(OH){sub 2} in the layer. There is a transitional layer with the thickness of about 200 nm between the Zn{sub 2}Mg alloy layer and the pure Zn layer, whose components consist of zinc-magnesium alloy without fixed stoichiometry, a little MgO and a little Mg(OH){sub 2}.

  9. High Temperature Sulfidation Behavior of Laser Alloying with Al Flame Sprayed Coating on Mild Steel

    International Nuclear Information System (INIS)

    A mild steel substrate was coated with Al wire by flame spraying and irradiated with CO2 laser to produce surface modification layer. The isothermal sulfidation behavior on CO2 laser surface alloyed layers were investigated at high temperature(1123k) in sulfidation environment (Ps2= 10-3 Pa) for 48 hours. Generally, surface alloyed layers were uniformed and their porosities were little. These structures were α Fe-Al, since Al concentration was analyzed from 36.3 to 48.5 percentages. The sulfidation kinetics of surface alloyed layers were shown to follow parabolic rate law during isothermal sulfidation, however the sulfidation rate of FA13(13 mm/min, 36% Al) specimen was approximately decreased from one-fifth lower than FA25(25 mm/min, 39% Al) and FA50(50 mm/min, 48% Al) specimen. Interface of FA50 surface alloyed layer was existed to the Al2S3 sulfide and Al2O3 oxide. By calculating partial pressure of impurity oxygen contained in H2S/H2 gas, the Al2O3 oxide formation could be explained using Fe-Al-S-O thermodynamical stability diagram

  10. Microstructural characterization of a friction stir welded oxide dispersion strengthened ferritic steel alloy

    International Nuclear Information System (INIS)

    Full text of publication follows: The fusion and fission reactors are faced with important challenges, notably in the field of materials. A class of materials, susceptible to resist to the required severe environments, is the ODS family (Oxide Dispersion Strengthened), who are metallic alloys strengthened by a very fine oxide dispersion. An obstacle to the development of these materials is their weldability because conventional fusion welding methods can disturb the fine oxide dispersion in the alloy that leads to a degradation of the high temperature behavior. Consequently, the Friction Stir Welding (FSW), which is a solid-state joining process, could be an alternative way to weld ODS alloys while keeping the fine microstructure. In this framework, the goal of this study is to make a microstructural characterization of a friction stir welded ODS alloy. The welded material is constituted by two plates of a yttria dispersion-strengthened PM 2000 ferritic steel. Different areas (non welded, heat affected zone and nugget) of the FSW welded product are analyzed by using field emission gun secondary electron microscopy (FEG-SEM), electron microprobe and transmission electron microscopy (TEM). The observed evolution of the microstructure, as the modification of the size and the repartition of the yttria dispersoids, after friction stir welding process is discussed and a correlation between the microstructural examinations and the results of nano-indentation tests is established. (authors)

  11. Effect of welding thermal cycle on the structure and properties of new effective alloying chromium-manganese-nickel steels

    International Nuclear Information System (INIS)

    The structure and properties of efficiently alloyed chromium-manganese-nickel steels of three experimental meltings with variable content of manganese - 2% (meltings 1 and 2) and 10% (melting 3). Steel of melting 3 was additionally alloyed with molybdenum and vanadium, and that of melting 2 - with nitrogen. The effect of different cooling rates (5, 25, 100 deg C) corresponding to electroslag, automatic flux-shielded and manual arc weldings on the structure and properties of HAZ metal of the experimental melting steels. It is shown that to decrease grain growth and intensive carbide formation, when developing technology of the steel welding attempts should be made to decrease the duration of HAZ metal maintaining at high temperature and to increase cooling rate

  12. Effect of grain size on mechanical electrochemical and hydrogen embrittlement behaviour of a micro-alloy steel

    International Nuclear Information System (INIS)

    A fine grain micro-alloy steel subjected to various annealing treatments resulted in microstructure with different grain sizes. Optical, scanning and transmission electron microscopes are used for microstructural characterizations. Hardness measurement, tensile testing, electrochemical polarisation and hydrogen embrittlement (HE) studies have been carried out to assess the mechanical and corrosion behaviour of the steel. Annealing treatment resulted in increase of grain sizes with the increase of holding time, decrease of cooling rate; and an associated decrease of hardness and strength. TEM study of the steel showed the characteristics morphology and distribution of precipitates. Tensile specimens of different grain sizes of the steel cathodically charged in an electrochemical cell, followed by tensile testing did not exhibit appreciable loss of ductility. FESEM fractographs of hydrogen charged samples showed a few chain of voids along with the ductile cup-cone features for other states as well and a quasi-cleavage features in the coarse ferrite grains alloy.

  13. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

    Science.gov (United States)

    Howard, Stanley R.; Korinko, Paul S.

    2008-05-27

    A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated layers for brazing alloy, and the stainless steel tube are heated and cooled in a vacuum furnace at controlled rates, forming a bond of the copper foam rings to the stainless steel tube that improves heat transfer between the tube and the copper foam.

  14. Assessment of hydrogen cracking sensitivity of interfaces in welds between stainless and low alloy steels by a tensile separation test

    International Nuclear Information System (INIS)

    In PWR the primary coolant circuit is coated with 23 CN 20-10 and intermediary alloys are used for welds between main components (pressure vessel, steam generators, pressurizers) made of low alloy steels and stainless steel pipes. After description of the chemical and structural particularities of the bonding zone and evidencing of the interface sensitivity to H2 induced cracking, the paper presents the implementation of the tensile shearing test: preparation, procedure, evaluation, results achieved. The prominent role of the stress relief treatment is highlighted

  15. Calculation of the end-rolling strength in Q235 strip steel by the alloying electron structure parameters

    Institute of Scientific and Technical Information of China (English)

    LIU Zhilin; LIN Cheng; LIU Yan; GUO Yanchang

    2005-01-01

    Combined with the phase transformations in rolling, the phase configuration, the tensile strength, and the yield strength with different terminal rolling grain sizes in Q235 strip steel have been theoretically calculated using the covalent electron number (nA) of the strongest bond in phase cells and the interface electron density difference (Ap) in alloys. The calculated results agree well with the results of real production. Therefore, the calculation method of terminal rolling tensile and yield strength in the non-quenched-tempered steel containing pearlite is given by the alloying electron structure parameters.

  16. Effect of chloride and sulfate additions on corrosion of low alloy steel in high-temperature water

    International Nuclear Information System (INIS)

    The present paper investigates the effect of chloride and sulfate additions on corrosion of low-alloyed steel in a cladding flaw of a nuclear reactor pressure vessel using in-situ electrochemical impedance spectroscopy coupled to ex-situ characterization of the oxides by surface analytical techniques. Impedance data are interpreted by the mixed-conduction model for oxide films to yield estimates for the main kinetic and transport parameters of the corrosion process. It can be concluded that the effect of chloride/sulfate transients on low-alloyed steel oxides is moderate, concerns mostly the processes at the inner layer/coolant interface and is to a certain extent reversible

  17. Tempering of martensitic steel for fasteners: Effects of micro-alloying on microstructure and mechanical property evolution

    OpenAIRE

    Öhlund, C.E.I.C.

    2015-01-01

    The research presented in this thesis aims to deepen our understanding of the effect of micro-alloying on the microstructure and mechanical property evolution during tempering of martensitic steel for fasteners. The ongoing trend of engine down-sizing has led to the need for stronger and more temperature resistant fasteners than currently available according to international standards. A new martensitic fastener steel called KNDS4 has been developed, that combines higher strength with improve...

  18. Modeling of primary dendrite arm spacing variations in thin-slab casting of low carbon and low alloy steels

    OpenAIRE

    Mehrara, H; Santillana, B; Eskin, DG; Boom, R; Katgerman, L; Abbel, G

    2011-01-01

    Solidification structure of a High Strength Low Alloy (HSLA) steel, in terms of dendrite arm spacing distribution across the shell thickness, is studied in a breakout shell from a thin-slab caster at Tata Steel in IJmuiden. Columnar dendrites were found to be the predominant morphology throughout the shell with size variations across the shell thickness. Primary Dendrite Arm Spacing (PDAS) increases by increasing the distance from meniscus or slab surface. Subsequently, a model is proposed to...

  19. Effect of welding processes on mechanical and microstructural characteristics of high strength low alloy naval grade steel joints

    OpenAIRE

    S. Ragu Nathan; V. Balasubramanian; S. Malarvizhi; Rao, A G

    2015-01-01

    Naval grade high strength low alloy (HSLA) steels can be easily welded by all types of fusion welding processes. However, fusion welding of these steels leads to the problems such as cold cracking, residual stress, distortion and fatigue damage. These problems can be eliminated by solid state welding process such as friction stir welding (FSW). In this investigation, a comparative evaluation of mechanical (tensile, impact, hardness) properties and microstructural features of shielded metal ar...

  20. Influence of the pulsed plasma treatment on the corrosion resistance of the low-alloy steel plated by Ni-based alloy

    Science.gov (United States)

    Dzhumaev, P.; Yakushin, V.; Kalin, B.; Polsky, V.; Yurlova, M.

    2016-04-01

    This paper presents investigation results of the influence of high temperature pulsed plasma flows (HTPPF) treatment on the corrosion resistance of low-alloy steel 0.2C-Cr-Mn- Ni-Mo cladded by the rapidly quenched nickel-based alloy. A technique that allows obtaining a defect-free clad layer with a good adhesion to the substrate was developed. It is shown that the preliminary treatment of steel samples by nitrogen plasma flows significantly increases their corrosion resistance in the conditions of intergranular corrosion test in a water solution of sulfuric acid. A change of the corrosion mechanism of the clad layer from intergranular to uniform corrosion was observed as a result of sub-microcrystalline structure formation and homogeneous distribution of alloying elements in the plasma treated surface layer thus leading to the significant increase of the corrosion resistance.

  1. Alloying the X40CrMoV5-1 steel surface layer with tungsten carbide by the use of a high power diode laser

    International Nuclear Information System (INIS)

    The paper presents the effect of alloying with tungsten carbide on properties of the X40CrMoV5-1 steel surface layer, using the high power diode laser (HPDL). Selection of laser operating conditions is discussed, as well as thickness of the alloying layer, and their influence on structure and chemical composition of the steel. Analysis of the influence of the process conditions on the thicknesses of the alloyed layer and heat-affected zone is presented

  2. Alloying the X40CrMoV5-1 steel surface layer with tungsten carbide by the use of a high power diode laser

    Energy Technology Data Exchange (ETDEWEB)

    Dobrzanski, L.A. [Institute of Engineering Materials and Biomaterials, Silesian University of Technology, 44-100 Gliwice, Konarskiego St. 18A (Poland); Bonek, M. [Institute of Engineering Materials and Biomaterials, Silesian University of Technology, 44-100 Gliwice, Konarskiego St. 18A (Poland)]. E-mail: mb@zmn.mt.polsl.gliwice.pl; Hajduczek, E. [Institute of Engineering Materials and Biomaterials, Silesian University of Technology, 44-100 Gliwice, Konarskiego St. 18A (Poland); Klimpel, A. [Welding Department, Silesian University of Technology, 44-100 Gliwice, Konarskiego St. 18A (Poland)

    2005-07-15

    The paper presents the effect of alloying with tungsten carbide on properties of the X40CrMoV5-1 steel surface layer, using the high power diode laser (HPDL). Selection of laser operating conditions is discussed, as well as thickness of the alloying layer, and their influence on structure and chemical composition of the steel. Analysis of the influence of the process conditions on the thicknesses of the alloyed layer and heat-affected zone is presented.

  3. Comparison of the thermal fatigue surface layers of the X40CrMoV5-1 hot work tool steels laser alloyed

    OpenAIRE

    L.A. Dobrzański; E. Jonda; A. Polok; A. Klimpel

    2007-01-01

    Purpose: The comparison of thermal fatigue and mechanical properties of the hot work tool steels alloyed with carbide powders has been presented. The effect of laser alloying with powders on the surface layers alloying with HPDL was evaluated.Design/methodology/approach: In this paper the result of laser surface alloying is discussed. The material used for investigation were hot work tool steels X40CrMoV5-1 and 55NiCrMoV7 alloyed with TiC or TaC using high power diode laser.Findings: Th...

  4. Development of Semi-Stochastic Algorithm for Optimizing Alloy Composition of High-Temperature Austenitic Stainless Steels (H-Series) for Desired Mechanical and Corrosion Properties.

    Energy Technology Data Exchange (ETDEWEB)

    Dulikravich, George S.; Sikka, Vinod K.; Muralidharan, G.

    2006-06-01

    The goal of this project was to adapt and use an advanced semi-stochastic algorithm for constrained multiobjective optimization and combine it with experimental testing and verification to determine optimum concentrations of alloying elements in heat-resistant and corrosion-resistant H-series stainless steel alloys that will simultaneously maximize a number of alloy's mechanical and corrosion properties.

  5. Mechanical properties of low-alloy-steels with bainitic microstructures and varying carbon content

    Science.gov (United States)

    Weber, A.; Klarner, J.; Vogl, T.; Schöngrundner, R.; Sam, G.; Buchmayr, B.

    2016-03-01

    Materials used in the oilfield industry are subjected to special conditions. These requirements for seamless steel tubes are between the priorities of strength, toughness and sour gas resistance. Steels with bainitic microstructure provide a great opportunity for those harsh environmental conditions. With different morphologies of bainite, like carbide free, upper or lower bainite, the interaction of high tensile strength and elongation is assumed to be better than with tempered martensite. To form carbide free bainite two ways of processing are proposed, isothermal holding with accurate time control or controlled continuous cooling. Both require knowledge of time-temperature transformation behaviour, which can be reached through a detailed alloying concept, focused on the influence of silicon to supress the carbide nucleation and chromium to stabilize the austenite fraction. The present work is based on three alloys with varying silicon and chromium contents. The carbide free microstructure is obtained by a continuous cooling path. Additionally different heat treatments were done to compare the inherent performance of the bainitic morphologies. The bainitic structures were characterized metallographically for their microstructure and the primary phase by means of transmission electron microscopy. The mechanical properties of carbide-free structures were analysed with quasi-static tensile tests and Charpy impact tests. Moreover, investigations about hydrogen embrittlement were done with focus on the effect of retained austenite. The results were ranked and compared qualitatively.

  6. Low temperature mechanical properties, fractographic and metallographic evaluation of several alloy steels

    Science.gov (United States)

    Montano, J. W.

    1973-01-01

    The mechanical properties are presented of alloy steels, 4130, 4140, 4340, 6150, and 8740. Test specimens were manufactured from approximately 1.00 inch (2.54 cm) diameter bar stock which had been heat treated to two different hardness levels. The following mechanical tests were performed at temperatures of 80 F (+26.7 C), 0 F (-17.8 C), -100 F (-73 C), and -200 F (-129 C): (1) tensile test (Ultimate, yield, modulus, elongation, and reduction of area), (2) notched tensile test, (3) charpy V-notched impact test (impact energy), and (4) double shear strength test (ultimate and yield). The test data indicate excellent tensile strength, notched/unnotched tensile ratios, ductility, impact, and shear properties at all test temperatures, except at -200 F (-129 C) where the impact strength of the higher strength group of alloy steels, 4130 (Rc-37) and 4140 (Rc-44) decreased to approximately 9 ft. lbs. (12 joules) and 6 ft. lbs. (8 joules), respectively. Chemical, metallographic, and fractographic analyses were also performed to evaluate microstructure, microhardness and the effect of decrease in temperature on the ductile to brittle failure transition.

  7. Strain-induced Precipitation in Ti Micro-alloyed Interstitial-free Steel

    Institute of Scientific and Technical Information of China (English)

    Ya-jun HUI; Yang YU; Lin WANG; Chang WANG; Wen-yuan LI; Bin CHEN

    2016-01-01

    Stress relaxation method was carried out on a Ti micro-alloyed interstitial-free (IF)steel at the tempera-ture ranging from 800 to 1 000 ℃.The results show that the softening kinetics curves of deformed austenite can be divided into three stages.At the first stage,the stress has a sharp drop due to the onset of recrystallization.At the second stage,a plateau appears on the relaxation curves indicating the start and finish of strain-induced precipitation. At the third stage,the stress curves begin to descend again because of coarsening of precipitates.Precipitation-time-temperature (PTT)diagram exhibited a “C”shape,and the nose point of the PTT diagram is located at 900 ℃ and the start precipitation time of 10 s.The theoretical calculation shows that the strain-induced precipitates were con-firmed as almost pure TiC particles.The TiC precipitates were heterogeneously distributed in either a chain-like or cell-like manner observed by transmission electron microscopy (TEM),which indicates the precipitates nucleated on dislocations or dislocation substructures.In addition,a thermodynamic analytical model was presented to describe the precipitation in Ti micro-alloyed IF steel,which shows a good agreement between the experimental observation and the predictions of the model.

  8. High corrosion resistance of austenitic stainless steel alloyed with nitrogen in an acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Metikos-Hukovic, M., E-mail: mmetik@fkit.h [Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 100000 Zagreb (Croatia); Babic, R. [Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 100000 Zagreb (Croatia); Grubac, Z. [Department of General and Inorganic Chemistry, Faculty of Chemistry and Technology, University of Split, 21000 Split (Croatia); Petrovic, Z. [Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 100000 Zagreb (Croatia); Lajci, N. [Faculty of Mine and Metallurgy, University of Prishtina, 10000 Prishtina, Kosovo (Country Unknown)

    2011-06-15

    Highlights: {yields} ASS alloyed with nitrogen treated at 1150 {sup o}C exhibits microstructure homogeneity. {yields} Passivation peak of ASS corresponds to oxidation of metal and absorbed hydrogen. {yields} Transfer phenomena and conductivity depend on the film formation potential. {yields} Electronic structure of the passive film and its corrosion resistance correlate well. {yields} Passive film on ASS with nitrogen is low disordered and high corrosion resistant. - Abstract: Passivity of austenitic stainless steel containing nitrogen (ASS N25) was investigated in comparison with AISI 316L in deareated acid solution, pH 0.4. A peculiar nature of the passivation peak in a potentiodynamic curve and the kinetic parameters of formation and growth of the oxide film have been discussed. The electronic-semiconducting properties of the passive films have been correlated with their corrosion resistance. Alloying austenitic stainless steel with nitrogen increases its microstructure homogeneity and decreases the concentration of charge carriers, which beneficially affects the protecting and electronic properties of the passive oxide film.

  9. High corrosion resistance of austenitic stainless steel alloyed with nitrogen in an acid solution

    International Nuclear Information System (INIS)

    Highlights: → ASS alloyed with nitrogen treated at 1150 oC exhibits microstructure homogeneity. → Passivation peak of ASS corresponds to oxidation of metal and absorbed hydrogen. → Transfer phenomena and conductivity depend on the film formation potential. → Electronic structure of the passive film and its corrosion resistance correlate well. → Passive film on ASS with nitrogen is low disordered and high corrosion resistant. - Abstract: Passivity of austenitic stainless steel containing nitrogen (ASS N25) was investigated in comparison with AISI 316L in deareated acid solution, pH 0.4. A peculiar nature of the passivation peak in a potentiodynamic curve and the kinetic parameters of formation and growth of the oxide film have been discussed. The electronic-semiconducting properties of the passive films have been correlated with their corrosion resistance. Alloying austenitic stainless steel with nitrogen increases its microstructure homogeneity and decreases the concentration of charge carriers, which beneficially affects the protecting and electronic properties of the passive oxide film.

  10. Tribological Properties of WS2 Nanoparticles Lubricants on Aluminum-Silicon Alloy and Carbon Steels

    Directory of Open Access Journals (Sweden)

    Riyadh A. AL-SAMARAI

    2013-06-01

    Full Text Available The rheological properties of nanometric tungsten disulphide (WS2 nanoparticles oil lubricants and its tribological performance with two hypereutectic Al-Si alloy and carbon steel are examined. These two oils are used to reduce wear and friction and to explore the actions via tribological pin-on-disk tests. The pin was made from hypereutectic Al-Si alloy on steel disk, taking into consideration the effect of loads (10, 20, 30 N and different speed (200, 300, 400 rpm. Oils with and without WS2 nanoparticles reveal the loss rate due to friction. The results show that WS2 nanoparticles oil-dispersed lubricants are capable of reducing wear, improved by a mechanism which was characterized not only by the viscosity of the WS2 nanoparticles suspensions but also the promotion of contact’s surface as combined anti-corrosion, as well as effective reduction of friction on the surface film. Therefore, a lubricant added to nanoparticles can protect the piston surface.

  11. Corrosion of aluminium, stainless steels and AISI 680 nickel alloy in nitrogen-based fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kap, I.; Starostin, M.; Shter, G.E.; Grader, G.S. [Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa (Israel)

    2012-07-15

    Nitrogen-based compounds can potentially be used as alternative non-carbon or low-carbon fuels. Nevertheless, the corrosion of construction materials at high temperatures and pressures in the presence of such fuel has not been reported yet. This work is focused on the corrosion of AISI Al 6061, 1005 carbon steel (CS), 304, 316L, 310 austenitic stainless steels (SS) and 680 nickel alloy in highly concentrated water solution of ammonium nitrate and urea (ANU). The corrosion at 50 C and ambient pressure and at 350 C and 20 bar was investigated to simulate storage and working conditions. Sodium chloride was added to the fuel (0-5 wt%) to simulate industrial fertilizers and accelerated corrosion environment. Heavy corrosion of CS was observed in ANU solution at 50 C, while Al 6061, 304 and 316L SS showed high resistance both to uniform and pitting corrosion in ANU containing 1% of sodium chloride. Addition of 5% sodium chloride caused pitting of Al 6061 but had no influence on the corrosion of SS. Tests in ANU at 350 C and 20 bar showed pitting on SS 304 and 316L and 680 nickel alloy. The highest corrosion resistance was found for SS 310 due to formation of stable oxide film on its surface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Fracture Toughness (K1C) evaluation for dual phase medium carbon low alloy steels using circumferential notched tensile (CNT) specimens

    OpenAIRE

    Kenneth Kanayo Alaneme

    2011-01-01

    The fracture behavior of dual phase medium carbon low alloy steels produced using two different chemical compositions (A - 0.34C, 0.75Mn, 0.12Cr, 0.13Ni steel and B - 0.3C, 0.97Mn, 0.15Cr steel) was investigated using circumferential notched tensile (CNT) specimens. Intercritical treatments were performed on samples with composition A by 1) austenitizing at 860 °C for 1 hour cooling in air, then treating at 770 °C for 30 minutes before oil quenching; 2) austenitizing at 860 °C for 1 hour quen...

  13. Structure–property-correlation in laser surface alloyed AISI 304 stainless steel with WC + Ni + NiCr

    International Nuclear Information System (INIS)

    Highlights: ► Optimization of process parameters for development of WC dispersed composite with Ni + NiCr as binder. ► Development of fine grained γ-stainless steel with the dispersion of very fine carbides (WC, W2C, M6C and M23C6). ► A significantly improved microhardness of the top surface (to 700–1350 VHN) as compared to as-received matrix (220 VHN) and its correlation with microstructures. ► Detailed microstructural evolution of the alloyed zone and its correlation with process parameters. ► Graded hardness distribution is achieved when lased with a low scan speed. - Abstract: The present study concerns a detailed investigation of the characteristics and properties of the alloyed zone formed in laser surface alloyed AISI 304 stainless steel with WC + Ni + NiCr (in the ratio of 70:15:15). Laser surface alloying has been carried out using a 5 kW continuous wave (CW) Nd:YAG laser (at a beam diameter of 4 mm), with the output power ranging from 1 to 3 kW and scan speed from 0.005 m/s to 0.1 m/s by simultaneous feeding of precursor powder (at a flow rate of 20 mg/s) and using Ar shroud at a gas flow rate of 5 l/min. The effect of laser power and scan speed on the characteristics of the surface alloyed layer (microstructures, phases and composition) and property (microhardness) have been investigated in details. Laser surface alloying leads to development of fine grained γ-stainless steel with the dispersion of WC, W2C, M6C and M23C6. The microhardness of the alloyed zone is significantly improved to a maximum value of 1350 VHN as compared to 220 VHN of as-received γ-stainless steel. The optimum parameters for laser processing were derived.

  14. Growth of creep life of type-347H austenitic stainless steel by micro-alloying elements

    International Nuclear Information System (INIS)

    Research highlights: → B, Ce and N can improve the creep life significantly at high temperature. → The precipitate of B element at the grain boundaries can improve the creep life. → The removing O through Ce provided the steel with longer creep life. → N increased the creep life by stabilizing austenite and solid solution strengthening. - Abstract: The creep life of type-347H austenitic stainless steel modified with B, Ce and N was measured, and microstructures were analyzed by optical microscope, X-ray diffraction, scanning electron microscope and transmission electron microscope equipped with energy dispersive spectroscopy. The results indicate that B, Ce and N can improve the creep life significantly at high temperature. The growth of creep life was mainly due to the precipitate of B in the elemental form at the grain boundaries and the removing O through Ce. N addition made for solid solution strengthening and effectively suppressed the precipitate of δ-ferrite at high temperature. The micro-alloying elements have a beneficial effect on creep life of type-347H austenitic stainless steel at high temperature.

  15. Galvanic corrosion between carbon steel 1018 and Alloy 600 in crevice with boric acid solution

    International Nuclear Information System (INIS)

    This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 .deg. C and 2000∼10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperature while the corrosion rate increased with boron concentration. The experimental results obtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightly soluble boric acid phase. Moreover the galvanic corrosion rate calculated using initial galvanic coupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor

  16. Effects of LWR coolant environments on fatigue design curves of carbon and low-alloy steels

    International Nuclear Information System (INIS)

    The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. Figures I-9.1 through I-9.6 of Appendix I to Section III of the code specify fatigue design curves for structural materials. While effects of reactor coolant environments are not explicitly addressed by the design curves, test data indicate that the Code fatigue curves may not always be adequate in coolant environments. This report summarizes work performed by Argonne National Laboratory on fatigue of carbon and low-alloy steels in light water reactor (LWR) environments. The existing fatigue S-N data have been evaluated to establish the effects of various material and loading variables such as steel type, dissolved oxygen level, strain range, strain rate, temperature, orientation, and sulfur content on the fatigue life of these steels. Statistical models have been developed for estimating the fatigue S-N curves as a function of material, loading, and environmental variables. The results have been used to estimate the probability of fatigue cracking of reactor components. The different methods for incorporating the effects of LWR coolant environments on the ASME Code fatigue design curves are presented

  17. Effect of plasma nitrided layers on low- alloy steel on its hydrogen degradation

    Directory of Open Access Journals (Sweden)

    A. Zieliński

    2006-04-01

    Full Text Available Purpose: Purpose of this paper is evaluation of susceptibility to hydrogen degradation of structural low-alloy steel, plasma nitrided in the atmosphere with various contents of N2 and H2.Design/methodology/approach: Susceptibility of 34CrAlNi7-10 steel and samples with various plasma nitrided layers have been evaluated under monotonically increasing load in 0.005 M H2SO4 solution. Slow-strain rate tensile test (SSRT test was carried out under cathodic polarisation. Elongation, reduction in area, fracture energy and tensile strength were chosen as measures of susceptibility to hydrogen embrittlement. Fracture modes of failed samples were examined with the use of scanning electron microscope (SEM.Findings: All tested samples revealed susceptibility to hydrogen degradation under hydrogenation. Samples with nitrided layer have lower lost of reduction in are than base metal samples. The nitrided layer established in standard atmosphere 30% H2 and 70% N2 has the highest resistance to hydrogen degradation.Research limitations/implications: Further research should be taken to reveal the exact mechanism of increased plasticity of nitided layer with absorbed hydrogen.Practical implications: Plasma nitriding may prevent hydrogen charging of machines and vehicles parts in hydrogen generating environments, and thus decreasing susceptibility to hydrogen embrittlement.Originality/value: Under the increasing load and hydrogen generating environments plasma nitrided layers are effective barriers to hydrogen entry into a bulk of steel, and additionally increased plasticity of nitrided layers with absorbed hydrogen was observed.

  18. Microstructure and formability of ZnNi alloy electrodeposited sheet steel

    Energy Technology Data Exchange (ETDEWEB)

    Lin, C.S.; Lee, H.B.; Hsieh, S.H.

    2000-02-01

    ZnNi alloy electrodeposited sheet steels were made from a chloride bath using a high-speed flow cell. A Ni-rich flash coating was deposited first, upon which the ZnNi coating, with Ni contents ranging from 8 to 16 wt pct, was subsequently electrodeposited. It is demonstrated that the Ni content of the coating affects the forming properties and microstructure of the ZnNi coatings. The hardness of the ZnNi coating increased with Ni content, leading to poor formability and inferior adhesion of the coated steels, as evident from the large amount of coating loss during swift cupping and coating peel-off during low-temperature adhesion tests. On the other hand, the friction force between the coated steel and cupping die decreased with increasing Ni content. At low Ni contents of 8 wt pct, the coating had a porous equiaxed grain structure. As the Ni content increased, the coating surface changed to dense faceted morphologies. A pyramid morphology was observed for 16 wt pct ZnNi coatings. An X-ray diffraction (XRD) analysis showed that all coatings containing up to 16 wt pct Ni contained only {gamma} phase. Transmission electron microscopy (TEM) observations showed the 8 wt pct Ni coating to have a fine-grained structure, which changed to a columnar structure at 16 wt pct Ni. The formation of the columnar structure is explained by the smaller amount of hydrogen discharge as the bath Ni ion concentration increased.

  19. Effects of LWR coolant environments on fatigue design curves of carbon and low-alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, O.K.; Shack, W.J. [Argonne National Lab., IL (United States)

    1998-03-01

    The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. Figures I-9.1 through I-9.6 of Appendix I to Section III of the code specify fatigue design curves for structural materials. While effects of reactor coolant environments are not explicitly addressed by the design curves, test data indicate that the Code fatigue curves may not always be adequate in coolant environments. This report summarizes work performed by Argonne National Laboratory on fatigue of carbon and low-alloy steels in light water reactor (LWR) environments. The existing fatigue S-N data have been evaluated to establish the effects of various material and loading variables such as steel type, dissolved oxygen level, strain range, strain rate, temperature, orientation, and sulfur content on the fatigue life of these steels. Statistical models have been developed for estimating the fatigue S-N curves as a function of material, loading, and environmental variables. The results have been used to estimate the probability of fatigue cracking of reactor components. The different methods for incorporating the effects of LWR coolant environments on the ASME Code fatigue design curves are presented.

  20. Low-Temperature Toughening Mechanism in Thermomechanically Processed High-Strength Low-Alloy Steels

    Science.gov (United States)

    Hwang, Byoungchul; Lee, Chang Gil; Kim, Sung-Joon

    2011-03-01

    High-strength low-alloy (HSLA) steels were fabricated by varying thermomechanical processing conditions such as rolling and cooling conditions in the intercritical region, and the low-temperature toughening mechanism was investigated in terms of microstructure and the associated grain boundary characteristics. The steels acceleratedly cooled to relatively higher temperature had lower tensile strength than those acceleratedly cooled to room temperature due to the increased volume fraction of granular bainite or polygonal ferrite (PF) irrespective of rolling in the intercritical region, while the yield strength was dependent on intercritical rolling, and start and finish cooling temperatures, which affected the formation of PF and low-temperature transformation phases. The steel rolled in the intercritical region and cooled to 673 K (400 °C) provided the best combination of high yield strength and excellent low-temperature toughness because of the presence of fine PF and appropriate mixture of various low-temperature transformation phases such as granular bainite, degenerate upper bainite (DUB), lower bainite (LB), and lath martensite (LM). Despite the high yield strength, the improvement of low-temperature toughness could be explained by the reduction of overall effective grain size based on the electron backscattered diffraction (EBSD) analysis data, leading to the decrease in ductile-to-brittle transition temperature (DBTT).

  1. Friction stir weld assisted diffusion bonding of 5754 aluminum alloy to coated high strength steels

    International Nuclear Information System (INIS)

    Highlights: • Successful lap joints of Al 5754 sheet to coated DP600 and 22MnB5 steels. • Negligible effect of welding speed on mechanical properties of Al 5754/22MnB5 joints. • Lower strength of Al 5754/22MnB5 joints compared with Al 5754/DP600 joints. - Abstract: In the present paper friction stir-induced diffusion bonding is used for joining sheets of 5754 aluminum alloy to coated high strength steels (DP600 and 22MnB5) by promoting diffusion bonding in an overlap configuration. Mechanical performance and microstructures of joints were analyzed by overlap shear testing, metallography, and X-ray diffraction. Our results show that the strength of joint is dependent upon tool travel speed and the depth of the tool pin relative to the steel surface. The thickness and types of intermetallic compounds formed at the interface play a significant role in achieving a joint with optimum performance. That is, the formation of high aluminum composition intermetallic compounds (i.e. Al5Fe2) at the interface of the friction stir lap joint appeared to have a more negative effect on joint strength compared to the presence of high iron composition intermetallic phases (i.e. FeAl). This is in agreement with previously reported findings that FeAl intermetallic can improve the fracture toughness and interface strength in Al/St joints

  2. Quantitative observations of hydrogen-induced, slow crack growth in a low alloy steel

    Science.gov (United States)

    Nelson, H. G.; Williams, D. P.

    1973-01-01

    Hydrogen-induced slow crack growth, da/dt, was studied in AISI-SAE 4130 low alloy steel in gaseous hydrogen and distilled water environments as a function of applied stress intensity, K, at various temperatures, hydrogen pressures, and alloy strength levels. At low values of K, da/dt was found to exhibit a strong exponential K dependence (Stage 1 growth) in both hydrogen and water. At intermediate values of K, da/dt exhibited a small but finite K dependence (Stage 2), with the Stage 2 slope being greater in hydrogen than in water. In hydrogen, at a constant K, (da/dt) sub 2 varied inversely with alloy strength level and varied essentially in the same complex manner with temperature and hydrogen pressure as noted previously. The results of this study provide support for most of the qualitative predictions of the lattice decohesion theory as recently modified by Oriani. The lack of quantitative agreement between data and theory and the inability of theory to explain the observed pressure dependence of slow crack growth are mentioned and possible rationalizations to account for these differences are presented.

  3. Effect of superheat on macrostructure and macrosegregation in continuous cast low-alloy steel slabs

    Science.gov (United States)

    Pikkarainen, T.; Vuorenmaa, V.; Rentola, I.; Leinonen, M.; Porter, D.

    2016-03-01

    The effect of superheat on grain sedimentation and macrosegregation has been investigated using experimental castings of a low-alloyed steel grade. With a high superheat of ∼ 40 °C, the central equiaxed parts of the slabs consisted of randomly oriented fine dendrites but with a low superheat of ∼ 10 °C, coarse globular structures formed. The mean carbon content measured with optical emission spectroscopy was of the order of 15% smaller with coarse globular structures than in fine equiaxed dendritic structures. Electron probe microanalysis of other alloying elements indicates that the negative segregation in the slab central zones is caused by sedimentation of globulites. With superheat in the range ∼ 20 - 40 °C, the equiaxed zone is bordered by a columnar to equiaxed transition (CET) zone. In this region a positive macrosegregation of carbon and other alloying elements was observed. These phenomena are important when considering the through-thickness properties of the slabs and final products.

  4. 75 FR 57444 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe from the People's...

    Science.gov (United States)

    2010-09-21

    ... Standard, Line, and Pressure Pipe From China, 74 FR 57521 (November 6, 2009) and Certain Seamless Carbon... export restraints, the GOC is providing inputs to downstream producers of seamless pipe. \\8\\ See 75 FR at... International Trade Administration Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure...

  5. 75 FR 9163 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's...

    Science.gov (United States)

    2010-03-01

    ... Pipe from the People's Republic of China: Initiation of Countervailing Duty Investigation, 74 FR 52945..., 73 FR 70961 (November 24, 2008) (``Line Pipe from the PRC''). In that case, the Department determined... International Trade Administration Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure...

  6. 75 FR 69052 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's...

    Science.gov (United States)

    2010-11-10

    ... International Trade Administration Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe..., and pressure pipe (``seamless pipe'') from the People's Republic of China (``PRC''). In addition, the... value in the antidumping duty investigation of seamless pipe from the PRC. See Certain Seamless...

  7. 78 FR 25253 - Seamless Carbon and Alloy Steel Standard, Line, and Pressure From the People's Republic of China...

    Science.gov (United States)

    2013-04-30

    ...The Department of Commerce (``the Department'') is rescinding the administrative review of the countervailing duty order on certain seamless carbon and alloy steel standard, line, and pressure pipe (``seamless pipe'') from the People's Republic of China (``PRC'') for the period January 1, 2011, through December 31,...

  8. 77 FR 56809 - Certain Small Diameter Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From...

    Science.gov (United States)

    2012-09-14

    ..., seamless pipes are seamless carbon and alloy (other than stainless) steel pipes, of circular cross-section... produced in non- standard wall thicknesses are commonly referred to as tubes. The seamless pipes subject to.... Seamless line pipes are produced to the API 5L specification. Seamless pipes are commonly produced...

  9. 75 FR 13255 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe from the People's...

    Science.gov (United States)

    2010-03-19

    ... Pressure Pipe From the People's Republic of China: Initiation of Antidumping Duty Investigation, 74 FR... International Trade Administration Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe..., line, and pressure pipe (``seamless pipe'') from the People's Republic of China (``PRC'') with...

  10. Assessment of The Cracking Properties of Stainless Steel Alloys and their Usability for Laser Welding in Production

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther

    2001-01-01

    Methods to assess stainless steel alloys’ cracking properties and usability for laser welding has been studied. Also tests to assess alloys’ susceptibility to hot cracking has been conducted. Among these is the so-called Weeter test which assesses the alloy by executing a number of spot welds to ...

  11. Computer simulation of the influence of the alloying elements on secondary hardness of the high-speed steels

    International Nuclear Information System (INIS)

    The paper presents the method of modelling of high-speed steels' (HSS) properties, being basing on chemical composition and heat treatment parameters, employing neural networks. An example of its application possibility the computer simulation was made of the influence of the particular alloying elements on hardness and obtained results are presented. (author)

  12. Tempering of martensitic steel for fasteners: Effects of micro-alloying on microstructure and mechanical property evolution

    NARCIS (Netherlands)

    Öhlund, C.E.I.C.

    2015-01-01

    The research presented in this thesis aims to deepen our understanding of the effect of micro-alloying on the microstructure and mechanical property evolution during tempering of martensitic steel for fasteners. The ongoing trend of engine down-sizing has led to the need for stronger and more temper

  13. A ferric-austenitic CrNiMoN steel alloy to be used as material to manufacture welded components

    International Nuclear Information System (INIS)

    A chromium-nickel-molybdenum-nitrogen steel alloy (ferritic-austenite) is used to manufacture welded articles which without thermal treatment are resistant to pitting corrosion, intergranular corrosion (Monypenny-Stauss test) or boiling in 65% nitric acid with subsequent cross-breaking test. (IHOE)

  14. Comparison of the corrosion behavior and surface morphology of NiTi alloy and stainless steels in sodium chloride solution

    Directory of Open Access Journals (Sweden)

    Kožuh S.

    2016-01-01

    Full Text Available The corrosion behavior of NiTi alloy and stainless steels (AISI 316L and X2CrNiMoN22-5-3 in 0.9% sodium chloride (0.154 moll-1 solution was investigated using open circuit potential measurements, potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Microstructural analyses before and after electrochemical tests were performed with the scanning electron microscopy (SEM equipped with energy dispersive spectrometry (EDS. The lowest corrosion current density has NiTi alloy and the extent of the passive range increased in the order AISI 316L stainless steel < NiTi alloy < X2CrNiMoN22-5-3 duplex stainless steel. The oxide film formed on all samples has a double-layer structure consisting of a barrier-type inner layer and a porous outer layer. Oxide films formed on the surface of steels mainly contains iron oxides and chromium oxide, while the surface film of the NiTi alloy mainly contains TiO2 oxide.

  15. 76 FR 49437 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2011-08-10

    ..., natural gas, and other liquids and gases in plumbing and heating systems, air conditioning units... Circumstances Review: Certain Circular Welded Non-Alloy Steel Pipe From Mexico, 75 FR 82374 (December 30, 2010... Venezuela and Amendment to Final Determination of Sales at Less Than Fair Value: Certain Welded...

  16. 75 FR 78216 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2010-12-15

    ... questionnaire response at Exhibit S-5. While TUNA had a general knowledge that some of its pipe would be... Mexico, 75 FR 67685 (November 3, 2010). Therefore, we are continuing to refer to this entity as TUNA for... Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453 (November 2, 1992) (Antidumping Duty Order)....

  17. 76 FR 76369 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Preliminary Results of the...

    Science.gov (United States)

    2011-12-07

    ... Less Than Fair Value: Certain Circular Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453 (November 2...: Light- Walled Rectangular Pipe and Tube From Mexico, 73 FR 5515, 5522 (January 30, 2008) (``LWR Pipe... Rectangular Pipe and Tube from Mexico, 73 FR 35649 (June 24, 2008). In particular, we analyze...

  18. 75 FR 44763 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico; Extension of Time Limit for Preliminary...

    Science.gov (United States)

    2010-07-29

    ... and Request for Revocation in Part, 74 FR 68229 (December 23, 2009). The current deadline for the... International Trade Administration Certain Circular Welded Non-Alloy Steel Pipe From Mexico; Extension of Time... Department) received a timely request from domestic interested parties Allied Tube and Conduit...

  19. 76 FR 66899 - Certain Circular Welded Non-Alloy Steel Pipe From Brazil, Mexico, the Republic of Korea, and...

    Science.gov (United States)

    2011-10-28

    ...-Alloy Steel Pipe and Tube from Mexico, 74 FR 41681 (August 18, 2009). \\3\\ The Department found that Yieh... (``Sunset'') Review, 76 FR 38613 (July 1, 2011) (Notice of Initiation). The Department received a notice of... Circumstance Review, 70 FR 71802 (November 30, 2005). This notice also serves as the only reminder to...

  20. 78 FR 76653 - Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and...

    Science.gov (United States)

    2013-12-18

    ... reviews were such that full reviews pursuant to section 751(c)(5) of the Act should proceed (78 FR 60316... Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and Tobago, and Ukraine Scheduling of full five-year reviews concerning the countervailing duty order on carbon and certain...

  1. 76 FR 34044 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Extension of Time Limits for the Preliminary...

    Science.gov (United States)

    2011-06-10

    ... Countervailing Duty Administrative Reviews, 75 FR 73036 (November 29, 2010) (``Initiation Notice''). The..., 70 FR 24533 (May 10, 2005). The final results continue to be due 120 days after the publication of... International Trade Administration Carbon and Certain Alloy Steel Wire Rod From Mexico: Extension of Time...

  2. 78 FR 78336 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Preliminary Results and Partial...

    Science.gov (United States)

    2013-12-26

    ...: Certain Circular Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453 (November 2, 1992). Notification to..., 77 FR 77017 (December 31, 2012). DATES: Effective Date: December 26, 2013. FOR FURTHER INFORMATION... Assessment Rate in Certain Antidumping Duty Proceedings; Final Modification, 77 FR 8101, 8102 (February...

  3. 75 FR 77838 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Preliminary Results of the...

    Science.gov (United States)

    2010-12-14

    ...: Certain Circular Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453 (November 2, 1992) (``CWP Order... Antidumping and Countervailing Duty Administrative Reviews and Request for Revocation in Part, 74 FR 68229... of 1930, as amended (``the Act''). See Initiation Notice, 74 FR at 68229. On January 6, 2010,...

  4. 76 FR 52636 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Partial Rescission of...

    Science.gov (United States)

    2011-08-23

    ... Administrative Review, 75 FR 67079 (November 1, 2010). In accordance with 19 CFR 351.213(b), on November 30, 2010... Revocation in Part, 75 FR 81565 (December 28, 2010). Wheatland withdrew its request for a review of Husteel... International Trade Administration Circular Welded Non-Alloy Steel Pipe From the Republic of Korea:...

  5. 76 FR 15941 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Extension of the Final Results...

    Science.gov (United States)

    2011-03-22

    ... From the Republic of Korea: Preliminary Results of the Antidumping Duty Administrative Review, 75 FR... the Tariff Act of 1930, As Amended, 70 FR 24533 (May 10, 2005). Accordingly, the deadline for... International Trade Administration Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Extension...

  6. 77 FR 34344 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Final Results of the Antidumping...

    Science.gov (United States)

    2012-06-11

    ...-Alloy Steel Pipe from Korea, 57 FR 49453 (November 2, 1992). These deposit requirements shall remain in... the Antidumping Duty Administrative Review, 76 FR 76369, 76374 (December 7, 2011) (``Preliminary... Results of the Antidumping Duty Administrative Review, 77 FR 8808 (February 15, 2012). We received...

  7. 77 FR 73015 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2012-12-07

    ...: Certain Circular Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453 (November 2, 1992). Notification to... Administrative Review, 63 FR 32833 (June 16, 1998), remains dispositive. Partial Rescission of Administrative...: Assessment of Antidumping Duties, 68 FR 23954 (May 6, 2003). For Husteel and HYSCO, we intend to...

  8. 77 FR 66954 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2012-11-08

    ... of Sales at Less Than Fair Value: Carbon and Certain Alloy Steel Wire Rod From Mexico, 67 FR 55800..., Trinidad and Tobago, and Ukraine, 67 FR 65945 (October 29, 2002), remains dispositive. On October 1, 2012... Rod from Mexico: Affirmative Final Determination of Circumvention of the Antidumping Duty Order, 77...

  9. Highly corrosion-resistant Zn-Mg alloy galvanized steel sheet for building construction materials; Kenzaiyo kotaishokusei yoyu Zn-Mg gokin mekki gohan 'daimajinku'

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, K.; Kato, K.; Shindo, H.

    1998-05-31

    The microstructure and corrosion product structure characteristics of the coating of highly corrosion-resistant Zn-Mg alloy galvanized steel sheet, designated 'Dymazinc' and developed to prolong the service life of civil engineering and building construction materials, are described. The magnesium is abundantly distributed near dendrites in the coating and forms a Zn-Mg intermetallic compound. This is the reason that the Zn-Mg alloy coating is harder than galvanized steel and provides superior sliding performance. The corrosion products of the Zn-Mg alloy coated steel are structurally denser than the galvanized steel and mainly inhibit the cathode reaction among the corrosion reactions. Coupled with the behavior of magnesium, the corrosion products are considered to be responsible for the high corrosion resistance of the Zn-Mg alloy galvanized steel sheet 'Dymazinc'. (author)

  10. Pack cementation Cr-Al coating of steels and Ge-doped silicide coating of Cr-Nb alloy

    Energy Technology Data Exchange (ETDEWEB)

    He, Y.R.; Zheng, M.H.; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States)

    1995-08-01

    Carbon steels or low-alloy steels used in utility boilers, heat exchangers, petrochemical plants and coal gasification systems are subjected to high temperature corrosion attack such as oxidation, sulfidation and hot corrosion. The pack cementation coating process has proven to be an economical and effective method to enhance the corrosion resistance by modifying the surface composition of steels. With the aid of a computer program, STEPSOL, pack cementation conditions to produce a ferrite Cr-Al diffusion coating on carbon-containing steels by using elemental Cr and Al powders have been calculated and experimentally verified. The cyclic oxidation kinetics for the Cr-Al coated steels are presented. Chromium silicide can maintain high oxidation resistance up to 1100{degrees}C by forming a SiO{sub 2} protective scale. Previous studies at Ohio State University have shown that the cyclic oxidation resistance of MOSi{sub 2} and TiSi{sub 2} can be further improved by Ge addition introduced during coating growth. The halide-activated pack cementation process was modified to produce a Ge-doped silicide diffusion coating in a single processing step for the ORNL-developed Cr-Nb advanced intermetallic alloy. The oxidation behavior of the silicide-coated Cr-Nb alloy was excellent: weight gain of about 1 mg/cm{sup 2} upon oxidation at 1100{degrees}C in air for 100 hours.

  11. Structure and properties of hotwork tool steel alloyed by WC carbides by a use of high power diode laser

    Directory of Open Access Journals (Sweden)

    M. Bonek

    2007-10-01

    Full Text Available Purpose: The paper presents the effect of alloying with tungsten carbide on properties of the X40CrMoV5-1 steel surface layer, using the high power diode laser (HPDL.Design/methodology/approach: The structural mechanism of surface layer development was determined and the effect of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer was studied.Findings: Selection of laser operating conditions is discussed, as well as thickness of the alloying layer, and their influence on structure and chemical composition of the steel. Analysis of the process conditions influence on thicknesses of the alloyed layer and heat-affected zone is presented.Practical implications: Laser surface modification has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones.Originality/value: The outcome of the research is an investigation showing the structural mechanisms accompanying laser alloying.

  12. Corrosion of high Ni-Cr alloys and Type 304L stainless steel in HNO3-HF

    International Nuclear Information System (INIS)

    Nineteen alloys were evaluated as possible materials of construction for steam heating coils, the dissolver vessel, and the off-gas system of proposed facilities to process thorium and uranium fuels. Commercially available alloys were found that are satisfactory for all applications. With thorium fuel, which requires HNO3-HF for dissolution, the best alloy for service at 1300C when complexing agents for fluoride are used is Inconel 690; with no complexing agents at 1300C, Inconel 671 is best. At 950C, six other alloys tested would be adequate: Haynes 25, Ferralium, Inconel 625, Type 304L stainless steel, Incoloy 825, and Haynes 20 (in order of decreasing preference); based on composition, six untested alloys would also be adequate. The ions most effective in reducing fluoride corrosion were the complexing agents Zr4+ and Th4+; Al3+ was less effective. With uranium fuel, modestly priced Type 304L stainless steel is adequate. Corrosion will be most severe in HNO3-HF used occasionally for flushing and in solutions of HNO3 and corrosion products (ferric and dichromate ions). HF corrosion can be minimized by complexing the fluoride ion and by passivation of the steel with strong nitric acid. Corrosion caused by corrosion products can be minimized by operating at lower temperatures

  13. Resistance of the alloy steel used in the fuel gas desulphurization installations; Odpornosc na korozje wzerowa stali stopowych stosowanych w instalacjach odsiarczania spalin

    Energy Technology Data Exchange (ETDEWEB)

    Krakowiak, S.; Darowski, K. [Politechnika Gdanska, Gdansk (Poland)

    1996-12-31

    The results have been presented of DC polarization and exposure investigations of alloy steels used as construction materials in flue gas desulphurization installations. on the base of analysis of composition of investigated steels and results of polarization studies, conditions have been discussed in which the pitting resistance equivalent (PRE) should be used. Among tested steels the significantly highest resistance to pitting corrosion is exhibited by 654SMO steel, classified as the super austenitic grade. (author). 14 refs, 3 figs, 2 tabs.

  14. Effect of aluminum on the corrosion resistance of low-alloy steel in 10 wt% sulfuric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Nam, N.D.; Kim, W.C.; Kim, J.G. [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon 440-746 (Korea, Republic of)

    2012-11-15

    The aqueous corrosion behavior of low-alloy steel with aluminum contents was examined in a 10 wt% H{sub 2}SO{sub 4} (pH 0.13) solution using electrochemical techniques and surface analyses. The corrosion resistance of the new alloy steel was evaluated in terms of electrochemical parameters, such as passive current density, film, and charge transfer resistances. The results showed that a high Al content in the steel imparted better passivation behavior resulting in a lower corrosion rate. It related to the enrichment of iron carbonate and hydrocarbon by the dissolution of the carbide phase. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Calculation of the yield and tensile strength in the alloying non quenched-tempered steel by the electron structure parameters

    Institute of Scientific and Technical Information of China (English)

    LIU Zhilin; LIN Cheng; LIU Yan; GUO Yanchang

    2005-01-01

    Based on the phase transformations and strengthening mechanisms during roiling, the strength increments △σb under different strengthening mechanisms are calculated with the covalent electron number nA of the strongest bond in phase cells of alloys and the interface electron density difference △ρ matching the interface stress in alloys. The calculation method of the finishing rolling yield strength is proposed, and it is integrated with the proposed calculation formulas of strength of non quenched-tempered steel. Therefore,the general formulas to simultaneously calculate both the finishing rolling strength and the yield strength of the continuous casting-rolling and non quenched-tempered steel are given. Taken the pipeline steel X70 as an example, the predictions of properties and technological parameters are performed before production or online.

  16. Modeling of primary dendrite arm spacing variations in thin-slab casting of low carbon and low alloy steels

    Science.gov (United States)

    Mehrara, H.; Santillana, B.; Eskin, D. G.; Boom, R.; Katgerman, L.; Abbel, G.

    2012-01-01

    Solidification structure of a High Strength Low Alloy (HSLA) steel, in terms of dendrite arm spacing distribution across the shell thickness, is studied in a breakout shell from a thin-slab caster at Tata Steel in IJmuiden. Columnar dendrites were found to be the predominant morphology throughout the shell with size variations across the shell thickness. Primary Dendrite Arm Spacing (PDAS) increases by increasing the distance from meniscus or slab surface. Subsequently, a model is proposed to describe the variation of the PDAS with the shell thickness (the distance from slab surface) under solidifiction conditions experienced in the primary cooling zone of thin-slab casting. The proposed relationship related the PDAS to the shell thickness and, hence, can be used as a tool for predicting solidifcation structure and optimizing the thin-slab casting of low alloy steels.

  17. Effect of mechanical alloying atmosphere on the microstructure and Charpy impact properties of an ODS ferritic steel

    International Nuclear Information System (INIS)

    Two types of oxide dispersion strengthened (ODS) ferritic steels, with the composition of Fe-14Cr-2W-0.3Ti-0.3Y2O3 (in weight percent), have been produced by mechanically alloying elemental powders of Fe, Cr, W, and Ti with Y2O3 particles either in argon atmosphere or in hydrogen atmosphere, degassing at various temperatures, and compacting the mechanically alloyed powders by hot isostatic pressing. It was found in particular that mechanical alloying in hydrogen yields a significant reduction in oxygen content in the materials, a lower dislocation density, and a strong improvement in the fast fracture properties of the ODS ferritic steels, as measured by Charpy impact tests.

  18. Effects of alloying elements and thermomechanical treatment on 9Cr Reduced Activation Ferritic–Martensitic (RAFM) steels

    International Nuclear Information System (INIS)

    RAFM steels are one of the candidate structural materials for fusion reactors, in which tantalum (Ta) and tungsten (W) are alloyed to replace niobium (Nb) and molybdenum (Mo) in conventional FM steels, respectively. This paper, using three RAFM heats, presents the effects of Ta and the primary austenite stabilizer carbon (C) on microstructure and strength. Thermomechanical treatment (TMT) was also applied to the heats, leading to significant increases in strength, attributable to the TMT-refined sub-grains and precipitates. The Ta-alloying favored the formation of (V, Ta)(N, C) and (Ta, V)C and exhibited greater strength. Fractographs also revealed the beneficial effects of TMT and Ta-alloying. However, extra C content, favoring a larger amount of M23C6 precipitates, did not show strengthening effect

  19. Effects of alloying elements and thermomechanical treatment on 9Cr Reduced Activation Ferritic–Martensitic (RAFM) steels

    Energy Technology Data Exchange (ETDEWEB)

    Tan, L., E-mail: tanl@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Yang, Y.; Busby, J.T. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2013-11-15

    RAFM steels are one of the candidate structural materials for fusion reactors, in which tantalum (Ta) and tungsten (W) are alloyed to replace niobium (Nb) and molybdenum (Mo) in conventional FM steels, respectively. This paper, using three RAFM heats, presents the effects of Ta and the primary austenite stabilizer carbon (C) on microstructure and strength. Thermomechanical treatment (TMT) was also applied to the heats, leading to significant increases in strength, attributable to the TMT-refined sub-grains and precipitates. The Ta-alloying favored the formation of (V, Ta)(N, C) and (Ta, V)C and exhibited greater strength. Fractographs also revealed the beneficial effects of TMT and Ta-alloying. However, extra C content, favoring a larger amount of M{sub 23}C{sub 6} precipitates, did not show strengthening effect.

  20. Evaluation of Stress Corrosion Cracking Susceptibility Using Fracture Mechanics Techniques, Part 1. [environmental tests of aluminum alloys, stainless steels, and titanium alloys

    Science.gov (United States)

    Sprowls, D. O.; Shumaker, M. B.; Walsh, J. D.; Coursen, J. W.

    1973-01-01

    Stress corrosion cracking (SSC) tests were performed on 13 aluminum alloys, 13 precipitation hardening stainless steels, and two titanium 6Al-4V alloy forgings to compare fracture mechanics techniques with the conventional smooth specimen procedures. Commercially fabricated plate and rolled or forged bars 2 to 2.5-in. thick were tested. Exposures were conducted outdoors in a seacoast atmosphere and in an inland industrial atmosphere to relate the accelerated tests with service type environments. With the fracture mechanics technique tests were made chiefly on bolt loaded fatigue precracked compact tension specimens of the type used for plane-strain fracture toughness tests. Additional tests of the aluminum alloy were performed on ring loaded compact tension specimens and on bolt loaded double cantilever beams. For the smooth specimen procedure 0.125-in. dia. tensile specimens were loaded axially in constant deformation type frames. For both aluminum and steel alloys comparative SCC growth rates obtained from tests of precracked specimens provide an additional useful characterization of the SCC behavior of an alloy.

  1. Hydrogen adsorption and diffusion, and subcritical-crack growth in high-strength steels and nickel base alloys

    Science.gov (United States)

    Wei, R. P.; Klier, K.; Simmons, G. W.

    1974-01-01

    Coordinated studies of the kinetics of crack growth and of hydrogen adsorption and diffusion were initiated to develop information that is needed for a clearer determination of the rate controlling process and possible mechanism for hydrogen enhanced crack growth, and for estimating behavior over a range of temperatures and pressures. Inconel 718 alloy and 18Ni(200) maraging steel were selected for these studies. 18Ni(250) maraging steel, 316 stainless steel, and iron single crystal of (111) orientation were also included in the chemistry studies. Crack growth data on 18Ni(250) maraging steel from another program are included for comparison. No sustained-load crack growth was observed for the Inconel 718 alloy in gaseous hydrogen. Gaseous hydrogen assisted crack growth in the 18Ni maraging steels were characterized by K-independent (Stage 2) extension over a wide range of hydrogen pressures (86 to 2000 torr or 12 kN/m2 to 266 kN/m2) and test temperatures (-60 C to +100 C). The higher strength 18Ni(250) maraging steel was more susceptible than the lower strength 200 grade. A transition temperature was observed, above which crack growth rates became diminishingly small.

  2. Combined effects of phosphorus segregation and partial intergranular fracture on the ductile-brittle transition temperature in structural alloy steels

    International Nuclear Information System (INIS)

    Research highlights: → Effective P segregation was proposed by segregated P and intergranular fracture. → The DBTT of aged and irradiated steel was analyzed by effective P segregation. → The DBTT of two classes of steels are controlled by differing mechanisms. → Hardening strongly influenced the embrittling potency of segregated P. - Abstract: This article introduced effective P segregation in terms of the product of the amount of segregated P and partial intergranular fracture to account for the combined effects on the ductile-brittle transition temperature (DBTT) measured by dynamic and static notched bar tests on several alloy steels. Effective P segregation characterized a DBTT shift caused by thermal ageing and/or neutron irradiation in various A533B and 2.25Cr-1Mo steels, while P segregation controlled the DBTT independent of the fraction of intergranular fracture in thermally aged 3.5Ni-1.7Cr steels with and without Mo and V. These DBTT behaviors of the two classes of steels are related to differing brittle fracture mechanisms. The present analysis enables one to investigate how the embrittling potency of segregated P in association with partial intergranular fracture is influenced by the differing plasticity and the addition of several alloying elements under dynamic and static loading conditions.

  3. Microstructures and mechanical properties of magnesium alloy and stainless steel weld-joint made by friction stir lap welding

    International Nuclear Information System (INIS)

    Highlights: → Friction stir lap welding technology with cutting pin was successfully employed to form lap joint of magnesium and steel. → The cutting pin made the lower steel participate in deformation and the interface was no longer flat. → A saw-toothed structure formed due to a mechanical mixing of the magnesium and steel was found at the interface. → A high-strength joint was produced which fractured in the magnesium side. -- Abstract: Friction stir lap welding was conducted on soft/hard metals. A welding tool was designed with a cutting pin of rotary burr made of tungsten carbide, which makes the stirring pin possible to penetrate and cut the surface layer of the hard metal. Magnesium alloy AZ31 and stainless steel SUS302 were chosen as soft/hard base metals. The structures of the joining interface were analyzed by scanning electron microscopy (SEM). The joining strength was evaluated by tensile shear test. The results showed that flower-like interfacial morphologies were presented with steel flashes and scraps, which formed bonding mechanisms of nail effect by long steel flashes, zipper effect by saw-tooth structure and metallurgical bonding. The shear strength of the lap joint falls around the shear strength of butt joint of friction stir welded magnesium alloy.

  4. Effects of austenite grain size and cooling rate on Widmanstaetten ferrite formation in low-alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Bodnar, R.L.; Hansen, S.S. (Bethlehem Steel Corp., PA (United States). Hot Rolled Products Div.)

    1994-04-01

    Deformation dilatometry is used to simulate the hot rolling of 0.20 pct C-1.10 pct Mn steels over a product thickness range of 6 to 170 mm. In addition to a base steel, steels with additions of 0.02 pct Ti, 0.06 pct V, or 0.02 pct Nb are included in the study. The transformation behavior of each steel is explored for three different austenite grain sizes, nominally 30, 55, and 100 [mu]m. In general, the volume fraction of Widmanstaetten ferrite increases in all four steels with increasing austenite grain size and cooling rate, with austenite grain size having the more significant effect. The Nb steel has the lowest transformation temperature range and the greatest propensity for Widmanstaetten ferrite formation, while the amount of Widmanstaetten ferrite is minimized in the Ti steel (as a result of intragranular nucleation of polygonal ferrite on coarse TiN particles). The data emphasize the importance of a refined austenite grain size in minimizing the formation of a coarse Widmanstaetten structure. With a sufficiently fine prior austenite grain size (e.g., [le]30 [mu]m), significant amounts of Widmanstaetten structure can be avoided, even in a Nb-alloyed steel.

  5. BEHAVIOUR OF COPPER AND ALUMINIUM ELECTRODES ON EDM OF EN-8 ALLOY STEEL

    Directory of Open Access Journals (Sweden)

    DHANANJAY PRADHAN

    2011-07-01

    Full Text Available Electrical discharge machining (EDM has been recognized as an efficient production method for precision machining of electrically conducting hardened materials. Copper and aluminium are used as electrode materials in this process with Kerosene oil as the dielectric medium. In this work, the behavior of copper and aluminium electrodes on electric discharge machining of EN-8 alloy steel had been studied. Keeping all other machining parameters same, the hardened work material was machined with the two electrodes at different values of peak current, pulse-on time & duty factor according to 23 full factorial design. It has been found that copper shows better results than aluminium in term of surface finish (μm in same dielectric media. Therefore, copper is recommended as a good electrode material.

  6. Influence of Post Weld Heat Treatment on the HAZ of Low Alloy Steel Weldments

    Directory of Open Access Journals (Sweden)

    S. Rasool Mohideen

    2010-06-01

    Full Text Available The heterogeneous nature of weldments demands an additional processing to retain and/or improve the joint properties. Heat Affected Zone, the zone Adjacent to the weld metal zone is critically affected by the sudden dissipation of heat from weld metal during welding. Toughness of this zone becomes weak as the grains get coarsened and the interface between the two regions is more prone to fracture. Post weld heat treatment is thus generally carried out on the weldments to relive the thermal residual stresses and to enhance the properties of welded joints. This paper discusses about the influence of post weld heat treatment on the fracture toughness of low alloy steel weldments. Fracture toughness of heat treated weldments was determined using standard CTOD test and the results were correlated.

  7. Direct Metal Deposition of H13 Tool Steel on Copper Alloy Substrate: Parametric Investigation

    Science.gov (United States)

    Imran, M. Khalid; Masood, S. H.; Brandt, Milan

    2015-12-01

    Over the past decade, researchers have demonstrated interest in tribology and prototyping by the laser aided material deposition process. Laser aided direct metal deposition (DMD) enables the formation of a uniform clad by melting the powder to form desired component from metal powder materials. In this research H13 tool steel has been used to clad on a copper alloy substrate using DMD. The effects of laser parameters on the quality of DMD deposited clad have been investigated and acceptable processing parameters have been determined largely through trial-and-error approaches. The relationships between DMD process parameters and the product characteristics such as porosity, micro-cracks and microhardness have been analysed using scanning electron microscope (SEM), image analysis software (ImageJ) and microhardness tester. It has been found that DMD parameters such as laser power, powder mass flow rate, feed rate and focus size have an important role in clad quality and crack formation.

  8. Pitting and crevice corrosion behaviour of high alloy stainless steels in chloride-fluoride solutions

    International Nuclear Information System (INIS)

    The localised corrosion resistance (pitting and crevice corrosion) of two high alloy stainless steels, namely superduplex (SD) and superaustenitic (SA), has been studied in chloride-fluoride solutions at pH values ranging from 2 to 6.5. The pitting potential (Epit) and crevice potential (Ecre) have been calculated for these test media using electrochemical techniques (continuous current). The critical pitting temperature (CPT) and critical crevice temperature (CCT) are in both materials lower then the room temperature. In spite of this fact and due to the high repassivation rate, the resistance of these materials to localised corrosion is high in the tested media. At the highest tested concentration of aggressive anions and pH 6.5 both materials undergo a generalised attack. (orig.)

  9. Thermal property characterization of a titanium modified austenitic stainless steel (alloy D9)

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Aritra [Physical Metallurgy Section, Materials Characterisation Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Raju, S. [Physical Metallurgy Section, Materials Characterisation Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)]. E-mail: sraju@igcar.ernet.in; Divakar, R. [Physical Metallurgy Section, Materials Characterisation Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Mohandas, E. [Physical Metallurgy Section, Materials Characterisation Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Panneerselvam, G. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Antony, M.P. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2005-12-01

    The temperature dependence of lattice parameter and enthalpy increment of alloy D9, a titanium modified nuclear grade austenitic stainless steel were studied using high temperature X-ray diffraction and inverse drop calorimetry techniques, respectively. A smooth variation of the lattice parameter of the austenite with temperature was found. The instantaneous and mean linear thermal expansion coefficients at 1350 K were estimated to be 2.12 x 10{sup -5} K{sup -1} and 1.72 x 10{sup -5} K{sup -1}, respectively. The measured enthalpy data were made use of in estimating heat capacity, entropy and Gibbs energy values. The estimated isobaric heat capacity C {sub p} at 298 K was found to be 406 J kg{sup -1} K{sup -1}. An integrated theoretical analysis of the thermal expansion and enthalpy data was performed to obtain approximate values of bulk modulus as a function of temperature.

  10. Analysis of copper alloy to stainless steel bonded panels for ITER first wall applications

    International Nuclear Information System (INIS)

    The mechanical performance of bi-layer copper alloy (Gildcop CuA115) to 316L stainless steel panels was examined. This work was to analyze potential bonding methodologies for the fabrication of ITER first wall structures, to verify the bond integrity of the fabricated panels, and to establish some mechanical performance parameters for panel structural performance. Two bonding routes were examined: explosively bonding and hot isostatically pressed (HIP) bonding. Following fabrication, the panels were mechanically loaded in tensile and fatigue tests. The mechanical performance test verified that the bond integrity was excellent, and that the primary mode of failure of the bonded panels was related to failure in the base materials rather than lack of adequate bond strength

  11. Special Features of Fracture of a Solid-State Titanium Alloy - Nickel - Stainless Steel Joint

    Science.gov (United States)

    Khazgaliev, R. G.; Mukhametrakhimov, M. Kh.; Imaev, M. F.; Shayakhmetov, R. U.; Mulyukov, R. R.

    2015-10-01

    Microstructure, nanohardness, and special features of fracture of three-phase titanium alloy and stainless steel joint through a nanostructural nickel foil are investigated. Uniformly distributed microcracks are observed in Ti2Ni and TiN3 layers joined at temperatures above T = 700°C, whereas no microcracks are observed in the TiNi layer. This suggests that the reason for microcracking is an anomalously large change in the linear expansion coefficient of the TiNi layer during austenitic-martensitic transformation. Specimens subjected to mechanical tests at T = 20°C are fractured along different layers of the material, namely, in the central part of the specimen they are fractured along the Ti2Тi/TiNi interface, whereas at the edge they are fractured along the TiNi/TiNi3 interface.

  12. Predicting the creep life and failure mode of low-alloy steel weldments

    Energy Technology Data Exchange (ETDEWEB)

    Brear, J.M.; Middleton, C.J.; Aplin, P.F. [ERA Technology Ltd., Leatherhead (United Kingdom)

    1998-12-31

    This presentation reviews and consolidates experience gained through a number of research projects and practical plant assessments in predicting both the life and the likely failure mode and location in low alloy steel weldments. The approach adopted begins with the recognition that the relative strength difference between the microstructural regions is a key factor controlling both life and failure location. Practical methods based on hardness measurement and adaptable to differing weld geometries are presented and evidence for correlations between hardness ratio, damage accumulation and strain development is discussed. Predictor diagrams relating weld life and failure location to the service conditions and the hardness of the individual microstructural constituents are suggested and comments are given on the implications for identifying the circumstances in which Type IV cracking is to be expected. (orig.) 6 refs.

  13. Alloying element losses in pulsed Nd : YAG laser welding of stainless steel 316

    International Nuclear Information System (INIS)

    Experimental studies of pulsed laser welding of stainless steel 316 in keyhole mode were done to examine a vaporization model based on the kinetic theory of gases and the thermodynamic laws. Undesirable loss of volatile elements affects the weld metal composition and properties. The profile of the keyhole was simulated as a function of time from a 'hydrodynamic' physical model. The power density and pulse duration were the main investigated variables. The model predicts that loss of alloying elements increases at higher peak powers and longer pulse durations. Accordingly, the concentrations of iron, chromium, nickel and manganese were determined in the weld pool by means of the proton-induced x-ray emission and energy dispersive x-ray/wavelength dispersive x-ray analysis. It was shown that the composition alteration, predicted by the model due to varying laser parameters, accords well with the corresponding experimental data.

  14. Development and industrial mastering hot rolling procedure for low-ductile steels and alloys

    International Nuclear Information System (INIS)

    The technique for the development of the sheet hot rolling procedure for low-ductile steels and alloys (0Kh17N14M2, 12Kh21N5T, 20Kh25N20C2,40Kh13, 36NKhTYu etc.) is proposed, using plastometer which permits to obtain the data on the deformation resistance in the wide range of temperatures (800-1300 deg C), of deformation degrees (0.1-0.3) and deformation rates (0.001-300 c-1). With the help of the plastometric data processed on the computer the calculation of the rolling regimes for the sheet with improved surface quality is carried out at the more uniform loading on the mill stands

  15. Iodine sorption/desorption from low-alloy steel and graphite. Draft

    International Nuclear Information System (INIS)

    Tests have been performed at Oak Ridge National Laboratory on the sorptive behavior of iodine on two prominent HTGR primary circuit materials - type H-451 graphite, which is the selected core graphite, and a low-alloy steel (T-22), a type which is employed in the lower temperature regions of the primary system. The main emphasis of the work is the determination of equilibrium sorptive capacities for very low iodine partial pressures. Toward this goal, the test procedures allow on-line determination of sorptive capacity down to iodine partial pressures of approx. 10-11 bar in helium at a total pressure of 1 atm. The apparatus employed is of the helium flow-through type. Detectors monitor the degree of sorption on specimens and traps, which, together with the helium flowrate and source vapor pressure, yield a continuous determination of iodine mass transport

  16. Iodine sorption and desorption from low-alloy steel and graphite

    International Nuclear Information System (INIS)

    Tests have been performed at Oak Ridge National Laboratory on the sorptive behaviour of iodine on two prominent HTGR primary circuit materials - type H-451 graphite, which is the selected core graphite, and a low-alloy steel (T-22), which is employed in the lower temperature regions of the primary system. The determination of equilibrium sorptive capacities at very low iodine partial pressures is emphasized in this work. Toward this goal, our test procedures allow on-line determination of the sorptive capacity down to iodine partial pressures of approximately 10-11 bar in helium at a total pressure of 1 bar. The apparatus employed is of the helium flow-through type. Detectors monitor the degree of sorption on specimens and traps, which, together with the helium flow rate and source vapor pressure, yields a continuous determination of iodine mass transport

  17. Status of ATR-A1 irradiation experiment on vanadium alloys and low-activation steels

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Strain, R.V.; Gomes, I.; Smith, D.L. [Argonne National Lab., IL (United States); Matsui, H. [Tohoku Univ. (Japan)

    1996-10-01

    The ATR-A1 irradiation experiment was a collaborative U.S./Japan effort to study at low temperature the effects of neutron damage on vanadium alloys. The experiment also contained a limited quantity of low-activation ferritic steel specimens from Japan as part of the collaboration agreement. The irradiation started in the Advanced Test Reactor (ATR) on November 30, 1995, and ended as planned on May 5, 1996. Total exposure was 132.9 effective full power days (EFPDs) and estimated neutron damage in the vanadium was 4.7 dpa. The vehicle has been discharged from the ATR core and is scheduled to be disassembled in the next reporting period.

  18. The effects of tempering reactions on temper embrittlement of alloy steels

    Science.gov (United States)

    Qu, Z.; McMahon, C. J.

    1983-06-01

    The effects of tempering reactions which produce molybdenum-rich carbides on the temper embrittlement of NiCrMo, NiCrMoV, CrMo, and CrMoV steels, particularly embrittlement due to phosphorus segregation, are reviewed. Molybdenum can act as an effective scavenger for phosphorus and other embrittling impurities, but the scavenging is lost when the molybdenum is precipitated in carbides as a result of continued tempering during service at elevated temperatures. This leads to very slow embrittlement, controlled by the rates of alloy carbide formation, rather than by the diffusion of phosphorus, for example. The presence of vanadium apparently retards the embrittlement process even more by interfering with the formation of the molybdenum-rich carbides. Observations of the temper embrittlement behavior, and of the effects of service exposure, in three CrMoV steam turbine rotors are also reported and are shown to be consistent with the previous results.

  19. Quantatitive fractographic details of low alloy pressure vessel steels fatigued in light water reactor environments

    International Nuclear Information System (INIS)

    The present paper attempts to describe the related environment assisted crack, EAC, growth and the quantitative fractography of the fatigue fracture surfaces observed during some fatigue tests on low alloy pressure vessel steels in high temperature aqueous environments which essentially simulated light water reactor, LWR, waters. It has been demonstrated that when EAC growth occurred it was associated with the development of static failure facets upon the fatigue fracture surfaces. In the present material-environment system the predominant static failure mode was fan-shaped, cleavage like, growth while a few instances of microvoid coalescence were also recorded. Indeed a strong relationship between the level of EAC growth and the area fraction of fan-shaped growth measured upon the fatigue fracture surface was clearly demonstrated

  20. Hydrogen permeation inhibition by zinc-nickel alloy plating on steel XC68

    International Nuclear Information System (INIS)

    The inhibition of hydrogen permeation and barrier effect by zinc-nickel plating was investigated using the Devanathan-Stachurski permeation technique. The hydrogen permeation and hydrogen diffusion for the zinc-nickel (12-15%) plating on steel XC68 is compared with zinc and nickel. Hydrogen permeation and hydrogen diffusion were followed as functions of time at current density applied (cathodic side) and potential permanent (anodic side). The hydrogen permeation inhibition for zinc-nickel is intermediate to that of nickel and zinc. This inhibition was due to nickel-rich layer effects at the Zn-Ni alloy/substrate interface, is shown by GDOES. Zinc-nickel plating inhibited the hydrogen diffusion greater as compared to zinc. This diffusion resistance was due to the barrier effect caused by the nickel which is present at the interface and transformed the hydrogen atomic to Ni2H compound, as shown by GIXRD.