Student Material for Competency-Based Education Curriculum for Welding.

Science.gov (United States)

Associated Educational Consultants, Inc., Pittsburgh, PA.

This student welding competency-based education curriculum consists of six units dealing with general areas related to trade occupations and nine units covering specific aspects of working with welding equipment and performing welding operations. Topics covered in the first six units are welding opportunities, human relations, safety, basic…

76 FR 68208 - Circular Welded Carbon-Quality Steel Pipe From India, Oman, United Arab Emirates, and Vietnam...

Science.gov (United States)

2011-11-03

... (Preliminary)] Circular Welded Carbon-Quality Steel Pipe From India, Oman, United Arab Emirates, and Vietnam... carbon-quality steel pipe from India, Oman, United Arab Emirates, and Vietnam, provided for in... Governments of India, Oman, United Arab Emirates, and Vietnam. Unless the Department of Commerce extends the...

Gas Metal Arc Welding. Welding Module 5. Instructor's Guide.

Science.gov (United States)

Missouri Univ., Columbia. Instructional Materials Lab.

This guide is intended to assist vocational educators in teaching an eight-unit module in gas metal arc welding. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The following topics are covered in the module: safety and testing, gas metal arc…

Friction Stir Welding

Science.gov (United States)

Nunes, Arthur C., Jr.

2008-01-01

Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and promises to be an important welding process for any industries where welds of optimal quality are demanded. This article provides an introduction to the FSW process. The chief concern is the physical effect of the tool on the weld metal: how weld seam bonding takes place, what kind of weld structure is generated, potential problems, possible defects for example, and implications for process parameters and tool design. Weld properties are determined by structure, and the structure of friction stir welds is determined by the weld metal flow field in the vicinity of the weld tool. Metal flow in the vicinity of the weld tool is explained through a simple kinematic flow model that decomposes the flow field into three basic component flows: a uniform translation, a rotating solid cylinder, and a ring vortex encircling the tool. The flow components, superposed to construct the flow model, can be related to particular aspects of weld process parameters and tool design; they provide a bridge to an understanding of a complex-at-first-glance weld structure. Torques and forces are also discussed. Some simple mathematical models of structural aspects, torques, and forces are included.

Welding.

Science.gov (United States)

Cowan, Earl; And Others

The curriculum guide for welding instruction contains 16 units presented in six sections. Each unit is divided into the following areas, each of which is color coded: terminal objectives, specific objectives, suggested activities, and instructional materials; information sheet; transparency masters; assignment sheet; test; and test answers. The…

76 FR 78615 - Circular Welded Carbon-Quality Steel Pipe From India, the Sultanate of Oman, the United Arab...

Science.gov (United States)

2011-12-19

...-810] Circular Welded Carbon-Quality Steel Pipe From India, the Sultanate of Oman, the United Arab..., the Sultanate of Oman (``Oman''), The United Arab Emirates (``the UAE''), and the Socialist Republic... Oman, the United Arab Emirates, and the Socialist Republic of Vietnam: Initiation of Countervailing...

Tensile strength of laser welded cobalt-chromium alloy with and without an argon atmosphere.

Science.gov (United States)

Tartari, Anna; Clark, Robert K F; Juszczyk, Andrzej S; Radford, David R

2010-06-01

The tensile strength and depth of weld of two cobalt chromium alloys before and after laser welding with and without an argon gas atmosphere were investigated. Using two cobalt chromium alloys, rod shaped specimens (5 cm x 1.5 mm) were cast. Specimens were sand blasted, sectioned and welded with a pulsed Nd: YAG laser welding machine and tested in tension using an Instron universal testing machine. A statistically significant difference in tensile strength was observed between the two alloys. The tensile strength of specimens following laser welding was significantly less than the unwelded controls. Scanning electron microscopy showed that the micro-structure of the cast alloy was altered in the region of the weld. No statistically significant difference was found between specimens welded with or without an argon atmosphere.

76 FR 72173 - Circular Welded Carbon-Quality Steel Pipe From India, the Sultanate of Oman, the United Arab...

Science.gov (United States)

2011-11-22

...-552-810] Circular Welded Carbon-Quality Steel Pipe From India, the Sultanate of Oman, the United Arab... Steel Pipe from India, Oman, the United Arab Emirates, and Vietnam, dated October 26, 2011 (hereinafter... pipe from India, the Sultanate of Oman (``Oman''), the United Arab Emirates (``the UAE''), and the...

49 CFR 179.300-9 - Welding.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.300-9 Section 179.300-9... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-9 Welding. (a) Longitudinal... fusion welded on class DOT-110A tanks. Welding procedures, welders and fabricators must be approved in...

Friction Stir Welding Process: A Green Technology

OpenAIRE

Esther T. Akinlabi; Stephen A. Akinlabi

2012-01-01

Friction Stir Welding (FSW) is a solid state welding process invented and patented by The Welding Institute (TWI) in the United Kingdom in 1991 for butt and lap welding of metals and plastics. This paper highlights the benefits of friction stir welding process as an energy efficient and a green technology process in the field of welding. Compared to the other conventional welding processes, its benefits, typical applications and its use in joining similar and dissimilar materia...

Effect of Manganese on the Mechanical Properties of Welded As-Cast Aluminium Joint

Directory of Open Access Journals (Sweden)

Isiaka Oluwole OLADELE

2013-11-01

Full Text Available The effects of manganese on the mechanical properties of welded and un-weld as-cast 6063 aluminium alloy has been studied. Alloys of varying percentage of manganese from 0.019 to 0.24 were sand cast. A wooden pattern of dimensions 200×100×100mm was used, the aluminium (500g was charged into an induction furnace and heated to 750°C for 15 minutes, this was followed by the addition of weighed powdered manganese, stirred and heated at the same temperature for another 5 minutes and thereafter poured into the already prepared sand mould at a temperature of 690°C. The as-cast aluminium samples, were sectioned into two equal parts of 45mm each using power hack saw; a weld groove was created between the sides of the samples using an electric hand grinding machine, the groove served as the path along which the filler metal was deposited on the aluminium, a single v butt joint was produced from each sample and Metal Inert Gas Welding process was carried out to produce the required joint design. The different cast samples were machined to the different test pieces after which they were assessed to determine their mechanical properties (impact, hardness (welded joint and heat affected zone and tensile tests. The microstructures of the welded samples were also studied. From the results, it was observed that Sample F, which has 0.172% Mn, has the best hardness and impact strength while sample C with 0.160% Mn has the highest ultimate tensile strength.

76 FR 72164 - Circular Welded Carbon-Quality Steel Pipe From India, the Sultanate of Oman, the United Arab...

Science.gov (United States)

2011-11-22

...-811] Circular Welded Carbon-Quality Steel Pipe From India, the Sultanate of Oman, the United Arab... Emirates, and Vietnam), or Angelica Mendoza (Oman), AD/CVD Operations, Office 7, Import Administration... Sultanate of Oman (Oman), the United Arab Emirates (UAE), and the Socialist Republic of Vietnam (Vietnam...

Automatic reel controls filler wire in welding machines

Science.gov (United States)

Millett, A. V.

1966-01-01

Automatic reel on automatic welding equipment takes up slack in the reel-fed filler wire when welding operation is terminated. The reel maintains constant, adjustable tension on the wire during the welding operation and rewinds the wire from the wire feed unit when the welding is completed.

Measurement of residual stresses in welded sample of dissimilar materials

International Nuclear Information System (INIS)

Mansur, Tanius Rodrigues; Gomes, Paulo de Tarso Vida; Scaldaferri, Denis Henrique Bianchi; Martins, Geraldo Antonio Scoralick; Atanazio Filho, Nelson do Nascimento

2008-01-01

The welding of dissimilar metals has several applications in the industry. Especially in the nuclear industry, this joint type, common between carbon steel and stainless steel, it is always reason of analysis and special cares tends in view the need to maintain the integrity of the equipment. Residual stresses are introduced in the material as a result of processes as welding, machining, sanding and polishing that can to produce deformation in the proximities of the surface of the material. Residual compressive stresses can be introduced in the material through the jetting process (bombardment of the surface for small glass spheres, dry sand or steel). That procedure allows a fine subsurface layer to suffer yielding, compressing the superficial layer and reducing the formation of areas of concentration of traction stresses, increasing the resistance of the material to the fatigue. The welding process introduces residual stresses due to the geometry resulting from the fusion of the material welded and of the heterogeneous cooling. Besides the microstructural alteration and chemical composition of the material in the affected area for the heat, introduced by the welding, it is also had the effect of the discontinuity of the passes and the formation of bubbles and emptiness that can contribute to the cracks nucleation, reducing the resistance to the fatigue. In the great majority of the times residual stresses are harmful and there are many documented cases which US these stresses went predominant factors for the failure for fatigue. A particularly dangerous aspect of the residual stresses is that their presence is not usually observed, what usually happens with an applied load to the structure. The knowledge of the surface residual stresses is important to predict the emergence of failure when the component or structure is requested. In nuclear power plants it is common to welding of piping of stainless steels with mouthpieces of carbon steel of pressure vases of

Effect of tool shape and welding parameters on mechanical properties and microstructure of dissimilar friction stir welded aluminium alloys

OpenAIRE

Chetan Aneja; Amit Handa

2016-01-01

In the present experimental study, dissimilar aluminum alloy AA5083 and AA6082 were friction stir welded by varying tool shape, welding speed and rotary speed of the tool in order to investigate the effect of varying tool shape and welding parameters on the mechanical properties as well as microstructure. The friction stir welding (FSW) process parameters have great influence on heat input per unit length of weld. The outcomes of experimental study prove that mechanical properties increases w...

Sturdy on Orbital TIG Welding Properties for Nuclear Fuel Test Rod

International Nuclear Information System (INIS)

Joung, Changyoung; Hong, Jintae; Kim, Kahye; Huh, Sungho

2014-01-01

We developed a precision TIG welding system that is able to weld the seam between end-caps and a fuel cladding tube for the nuclear fuel test rod and rig. This system can be mainly classified into an orbital TIG welder (AMI, M-207A) and a pressure chamber. The orbital TIG welder can be independently used, and it consists of a power supply unit, a microprocessor, water cooling unit, a gas supply unit and an orbital weld head. In this welder, the power supply unit mainly supplies GTAW power for a welding specimen and controls an arc starting of high frequency, supping of purge gas, arc rotation through the orbital TIG welding head, and automatic timing functions. In addition, the pressure chamber is used to make the welded surface of the cladding specimen clean with the inert gas filled inside the chamber. To precisely weld the cladding tube, a welding process needs to establish a schedule program for an orbital TIG welding. Therefore, the weld tests were performed on a cladding tube and dummy rods under various conditions. This paper describes not only test results on parameters of the purge gas flow rates and the chamber gas pressures for the orbital TIG welding, but also test results on the program establishment of an orbital TIG welding system to weld the fuel test rods. Various welding tests were performed to develop the orbital TIG welding techniques for the nuclear fuel test rod. The width of HAZ of a cladding specimen welded with the identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a weld end-point because of heat accumulation. The welding effect of the PGFR and CGP shows a relatively large difference for FSS and LSS. Each hole on the cladding specimens was formed in the 1bar CGP with the 20L/min PGFR but not made in the case of the PGFR of 10L/min in the CGP of 2bar. The optimum schedule program of the orbital TIG welding system to weld the nuclear fuel test rod was established through the program

Sturdy on Orbital TIG Welding Properties for Nuclear Fuel Test Rod

Energy Technology Data Exchange (ETDEWEB)

Joung, Changyoung; Hong, Jintae; Kim, Kahye; Huh, Sungho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

We developed a precision TIG welding system that is able to weld the seam between end-caps and a fuel cladding tube for the nuclear fuel test rod and rig. This system can be mainly classified into an orbital TIG welder (AMI, M-207A) and a pressure chamber. The orbital TIG welder can be independently used, and it consists of a power supply unit, a microprocessor, water cooling unit, a gas supply unit and an orbital weld head. In this welder, the power supply unit mainly supplies GTAW power for a welding specimen and controls an arc starting of high frequency, supping of purge gas, arc rotation through the orbital TIG welding head, and automatic timing functions. In addition, the pressure chamber is used to make the welded surface of the cladding specimen clean with the inert gas filled inside the chamber. To precisely weld the cladding tube, a welding process needs to establish a schedule program for an orbital TIG welding. Therefore, the weld tests were performed on a cladding tube and dummy rods under various conditions. This paper describes not only test results on parameters of the purge gas flow rates and the chamber gas pressures for the orbital TIG welding, but also test results on the program establishment of an orbital TIG welding system to weld the fuel test rods. Various welding tests were performed to develop the orbital TIG welding techniques for the nuclear fuel test rod. The width of HAZ of a cladding specimen welded with the identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a weld end-point because of heat accumulation. The welding effect of the PGFR and CGP shows a relatively large difference for FSS and LSS. Each hole on the cladding specimens was formed in the 1bar CGP with the 20L/min PGFR but not made in the case of the PGFR of 10L/min in the CGP of 2bar. The optimum schedule program of the orbital TIG welding system to weld the nuclear fuel test rod was established through the program

Comparative estimation of the properties of heat resisting nickel alloy welded joints made by electron-beam and arc welding

International Nuclear Information System (INIS)

Morochko, V.P.; Sorokin, L.I.; Yakushin, B.F.; Moryakov, V.F.

1977-01-01

As compared to argon arc welding of refractory nickel alloys at 15 m/hour rate, electron beam welding decreases energy consumption per unit length (from 4300 to 2070 cal/cm), the weld area (from 108 to 24 mm 2 ), and the length of the thermal effect zone (from 0.9-1.8 to 0.4-0.8 mm). Electron beam welding also provides for better resistance to hot cracking in the weld metal and in the near-weld zone, as compared to automatic argon arc welding and manual welding with addition of the basic metal. However, this advantage is observed only at welding rates less than 45 m/hour. Electron beam welded joints of refractory nickel alloys with intermetallide reinforcement have higher strength, plasticity and impact strength, and lower scattering of these properties than arc welded joints

Fracture mechanics characterisation of the WWER-440 reactor pressure vessel beltline welding seam of Greifswald unit 8

International Nuclear Information System (INIS)

Viehrig, Hans-Werner; Schuhknecht, Jan

2008-01-01

WWER-440 second generation (V-213) reactor pressure vessels (RPV) were produced by IZHORA in Russia and by SKODA in the former Czechoslovakia. The surveillance Charpy-V and fracture mechanics SE(B) specimens of both producers have different orientations. The main difference is the crack extension direction which is through the RPV thickness and circumferential for ISHORA and SKODA RPV, respectively. In particular for the investigation of weld metal from multilayer submerged welding seams the crack extension direction is of importance. Depending on the crack extension direction in the specimen there are different welding beads or a uniform structure along the crack front. The specimen orientation becomes more important when the fracture toughness of the weld metal is directly determined on surveillance specimens according to the Master Curve (MC) approach as standardised in the ASTM Standard Test Method E1921. This approach was applied on weld metal of the RPV beltline welding seam of Greifswald Unit 8 RPV. Charpy size SE(B) specimens from 13 locations equally spaced over the thickness of the welding seam were tested. The specimens are in TL and TS orientation. The fracture toughness values measured on the SE(B) specimens with both orientations follow the course of the MC. Nearly all values lie within the fracture toughness curves for 5% and 95% fracture probability. There is a strong variation of the reference temperature T 0 though the thickness of the welding seam, which can be explained with structural differences. The scatter is more pronounced for the TS SE(B) specimens. It can be shown that specimens with TS and TL orientation in the welding seam have a differentiating and integrating behaviour, respectively. The statistical assumptions behind the MC approach are valid for both specimen orientations even if the structure is not uniform along the crack front. By comparison crack extension, JR, curves measured on SE(B) specimens with TL and TS orientation show

Toxoplasmosis in sand cats (Felis margarita) and other animals in the Breeding Centre for Endangered Arabian Wildlife in the United Arab Emirates

Science.gov (United States)

The Sand cat (Felis margarita) is a small-sized felid occurring in the United Arab Emirates (UAE). The Sand cat captive breeding program at the Breeding Centre for Endangered Arabian Wildlife (BCEAW), Sharjah, UAE, has experienced high newborn mortality rates, and congenital toxoplasmosis was recent...

Thermal recovery characteristics of Kori-unit 1 linde 80 weld

International Nuclear Information System (INIS)

Chi, S. H.; Hong, J. H.; Kuk, I. H.; Kim, I. S.

1997-01-01

The recovery activation energy, the order of reaction and the characteristic recovery rate constant were determined by isochronal (573K -823K) and isothermal (723K - 775K) annealing experiments on specimens made from a broken half of a Kori-Unit 1 surveillance weld specimen (fluence: 1.21 x 10 23 n/m 2 , E (1MeV, Cu: 0.29 wt%) to investigate the recovery characteristics of a high copper weld of neutron-irradiated reactor pressure vessel (RPV). Vickers microhardness tests were conducted to trace the recovery behavior after heat treatments. The results were analyzed in terms of recovery stages, behavior of responsible defects and recovery kinetics. It was shown that recovery occurred through two annealing stages (stage I: 673K - 753K, stage II: 753K - 823K) with recovery activation energies of 2.68 eV and 2.83 eV for stage I and II, respectively. The isothermal hardness recovery at 723 K and 775 K coincided with the ratio of the characteristic rate constant for each recovery stage. The order of reaction was 2 for both recovery stages. The recovery activation energies of present specimens are approximately equal to that of copper diffusion in α-iron in the presence of vacancies, suggesting that recovery may occur through the diffusion of copper atoms. The present results strongly support the copper precipitate coarsening model. (author)

Emissions of chromium (VI) from arc welding.

Science.gov (United States)

Heung, William; Yun, Myoung-Jin; Chang, Daniel P Y; Green, Peter G; Halm, Chris

2007-02-01

The presence of Cr in the +6 oxidation state (Cr[VI]) is still observed in ambient air samples in California despite steps taken to reduce emissions from plating operations. One known source of emission of Cr(VI) is welding, especially with high Cr-content materials, such as stainless steels. An experimental effort was undertaken to expand and update Cr(VI) emission factors by conducting tests on four types of arc-welding operations: gas-metal arc welding (GMAW), shielded metal arc welding (SMAW), fluxcore arc welding, and pulsed GMAW. Standard American Welding Society hood results were compared with a total enclosure method that permitted isokinetic sampling for particle size-cut measurement, as well as total collection of the aerosol. The fraction of Cr(VI) emitted per unit mass of Cr electrode consumed was determined. Consistent with AP-42 data, initial results indicate that a significant fraction of the total Cr in the aerosol is in the +6 oxidation state. The fraction of Cr(VI) and total aerosol mass produced by the different arc welding methods varies with the type of welding process used. Self-shielded electrodes that do not use a shield gas, for example, SMAW, produce greater amounts of Cr(VI) per unit mass of electrode consumed. The formation of Cr(VI) from standard electrode wires used for welding mild steel was below the method detection limit after eliminating an artifact in the analytical method used.

Resistance welding equipment manufacturing capability for exports

Energy Technology Data Exchange (ETDEWEB)

Sastry, V.S.; Raju, Y.S.; Somani, A.K.; Setty, D.S.; Rameswara Raw, A.; Hermantha Rao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderbad (India)

2010-07-01

Indian Pressurised Heavy Water Reactor (PHWR) fuel bundle is fully welded and is unique in its design. Appendage welding, end closure welding, and end plate welding is carried out using resistance welding technique. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. Nuclear Fuel Complex (NFC), an industrial unit is established in Hyderabad, under the aegis of the Dept of Atomic Energy to manufacture fuel for Pressurised Heavy Water Reactors. From inception, NFC has given importance for self-reliance and indigenization with respect to manufacturing process and equipment. Sintering furnaces, centreless grinders, appendage-welding machines, end-closure welding equipment and end-plate welding equipments, which were initially imported, are either indigenized or designed and manufactured in house. NFC has designed, manufactured a new appendage-welding machine for manufacturing 37 element fuel bundles. Recently NFC has bagged an order from IAEA through international bidding for design, manufacture, supply, erection and commissioning of end-closure welding equipment. The paper gives in detail the salient features of these welding equipment. (author)

The application of TIG-welding to the manufacture of modern boiler units. Chapter 3

International Nuclear Information System (INIS)

Dick, N.T.

1978-01-01

Stringent weld acceptance standards are necessary in nuclear installations. Mechanised TIG-welding is being used exclusively in the manufacture of the boiler pods for the Hartlepool and Heysham nuclear generating stations. The choice of a TIG welding process is discussed. Reliability, access, welding position, tube dimensions and weld profile were important as was the desirability of having ferrite control because in the austenitic stainless steel used, the acceptance standard does not permit microfissuring. Development of the technique and production equipment and conditions are given for tube butt welding, tube-to-tubeplate bore welding and tube-to-tubeplate face welding in AGR applications. (U.K.)

Orbital friction stir welding of aluminium pipes

International Nuclear Information System (INIS)

Engelhard, G.; Hillers, T.

2002-01-01

Friction stir welding (FSW) was originally developed for flat plates. This contribution shows how it can be applied to the welding of aluminium pipes. Pipes made of AlMG 3 (EN5754), AlMg 4.5Mn (EN5083) and AlMgSi 0.5 (EN6106) with dimensions of Da 600 and 520 x 10-8 mm were welded. The FSW orbital system comprises an annular cage with integrated FSW head, a hydraulic system, and a control unit. The welds were tested successfully according to EN 288. The mechanical and technical properties of the welds were somewhat better than with the TIG orbital process, and welding times were about 40 percent shorter [de

Nd:YAG laser welding of aerospace grade ZE41A magnesium alloy: Modeling and experimental investigations

International Nuclear Information System (INIS)

Al-Kazzaz, H.; Medraj, M.; Cao, X.; Jahazi, M.

2008-01-01

Keyhole formation as well as the geometry of weld profiles during Nd:YAG laser welding of ZE41A-T5 were studied through combining various models and concepts. The results indicated that weld width and fusion area decrease with increasing welding speed. In the case of partially penetrated welding, penetration depth decreases with increasing welding speed. Also, the model predicted that excessive decrease in laser power or increase in defocusing distance decreases surface power density, thereby changing the welding mode from fully penetrated keyhole, to partially penetrated keyhole, and then to the conduction mode. The predicted conditions for keyhole stability and welding modes as well as the weld profiles for various processing conditions were validated by some selected welding experiments. These experiments included studying the effects of welding speed, laser power, joint gap and laser defocusing on the weld geometry of 2- and 6-mm butt joints or bead-on-plates of ZE41A-T5 sand castings using a continuous wave 4 kW Nd:YAG laser system and 1.6-mm EZ33A-T5 filler wire. Good agreements were found between the model predictions and experimental results indicating the validity of the assumptions made for the development of the model

Metal Working and Welding Operations.

Science.gov (United States)

Marine Corps Inst., Washington, DC.

This student guide, one of a series of correspondence training courses designed to improve the job performance of members of the Marine Corps, deals with the skills needed by metal workers and welders. Addressed in the six individual units of the course are the following topics: weldable metals and their alloys, arc welding, gas welding,…

Welding of the A1 reactor pressure vessel

International Nuclear Information System (INIS)

Becka, J.

1975-01-01

As concerns welding, the A-1 reactor pressure vessel represents a geometrically complex unit containing 1492 welded joints. The length of welded sections varies between 10 and 620 mm. At an operating temperature of 120 degC and a pressure of 650 N/cm 2 the welded joints in the reactor core are exposed to an integral dose of 3x10 18 n/cm 2 . The chemical composition is shown for pressure vessel steel as specified by CSN 413090.9 modified by Ni, Ti and Al additions, and for the welding electrodes used. The requirements are also shown for the mechanical properties of the base and the weld metals. The technique and conditions of welding are described. No defects were found in ultrasonic testing of welded joints. (J.B.)

Repair procedure used in removing corroded pits in the distillation towers of the Getulio Vargas Refinery Unit 2100

Energy Technology Data Exchange (ETDEWEB)

Lordelos, H.M.; Santin, J.L.

1977-07-01

A description is given of the corrosion pits on ASTM A240, Type 405 steel cladded to carbon steel plates used in Petroleo Brasileiro S.A.'s Getulio Vargas Refinery Unit 2100 distillation towers; the repair procedure used, including sand blasting of the corroded surfaces, grinding of the pits, and welding of those pits whose depth was above a maximum limit, and the use of liquid penetrant to check the repairs made; and hydrostatic testing of the T2201 catalytic cracking unit, which used also cladded metals and on which the pits were much smaller in size and number than those on the distillation units.

Standard practice for ultrasonic testing of the Weld Zone of welded pipe and tubing

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This practice describes general ultrasonic testing procedures for the detection of discontinuities in the weld and adjacent heat affected zones of welded pipe and tubing by scanning with relative motion between the search unit and pipe or tube. When contact or unfocused immersion search units are employed, this practice is intended for tubular products having specified outside diameters ≥2 in. (≥50 mm) and specified wall thicknesses of 1/8to 11/16 in. (3 to 27 mm). When properly focused immersion search units are employed, this practice may also be applied to material of smaller diameter and thinner wall. Note 1—When contact or unfocused immersion search units are used, precautions should be exercised when examining pipes or tubes near the lower specified limits. Certain combinations of search unit size, frequency, thin–wall thicknesses, and small diameters could cause generation of unwanted sound waves that may produce erroneous examination results. 1.2 All surfaces of material to be examined in ...

The Carolina Sandhills: Quaternary eolian sand sheets and dunes along the updip margin of the Atlantic Coastal Plain province, southeastern United States

Science.gov (United States)

Swezey, Christopher; Fitzwater, Bradley A.; Whittecar, G. Richard; Mahan, Shannon; Garrity, Christopher P.; Aleman Gonzalez, Wilma B.; Dobbs, Kerby M.

2016-01-01

The Carolina Sandhills is a physiographic region of the Atlantic Coastal Plain province in the southeastern United States. In Chesterfield County (South Carolina), the surficial sand of this region is the Pinehurst Formation, which is interpreted as eolian sand derived from the underlying Cretaceous Middendorf Formation. This sand has yielded three clusters of optically stimulated luminescence ages: (1) 75 to 37 thousand years ago (ka), coincident with growth of the Laurentide Ice Sheet; (2) 28 to 18 ka, coincident with the last glacial maximum (LGM); and (3) 12 to 6 ka, mostly coincident with the Younger Dryas through final collapse of the Laurentide Ice Sheet. Relict dune morphologies are consistent with winds from the west or northwest, coincident with modern and inferred LGM January wind directions. Sand sheets are more common than dunes because of effects of coarse grain size (mean range: 0.35–0.59 mm) and vegetation. The coarse grain size would have required LGM wind velocities of at least 4–6 m/sec, accounting for effects of colder air temperatures on eolian sand transport. The eolian interpretation of the Carolina Sandhills is consistent with other evidence for eolian activity in the southeastern United States during the last glaciation.

Small Bore Piping Socket Weld Evaluation System

International Nuclear Information System (INIS)

Lee, Dong Min; Cho, Hong Seok; Choi, Sang Hoon; Cho, Ki Hyun; Lee, Jang Wook

2009-01-01

Kori unit 3 had stopped operation due to leakage at Steam Generator drain line socket weld on June 6, 2008. The Cause of socket weld damage was known as a fatigue crack. According to this case, all socket welds located in RCS pressure boundary are carrying out Radiographic Testing. But to inspect socket welds by RT has some problems. The result of EPRI study showed that RT has limitation to find flaws at socket welds.The orientation of flaws has big influence on RT inspection capability and there is not enough space at socket welds for RT, dose problems as well. Although the gap between coupling and pipe at socket welds must follow up code, surface inspection can't inspect the gap. If there is absence of the gap, socket welds are damaged during operation. The gap should be identified by RT but the distance of gap can't be measured. As this paper, the ultrasonic inspection system was introduced to figure out indication and gap in the socket welds

Welding robot package; Arc yosetsu robot package

Energy Technology Data Exchange (ETDEWEB)

Nishikawa, S. [Yaskawa Electric Corp., Kitakyushu (Japan)

1998-09-01

For the conventional high-speed welding robot, the welding current was controlled mainly for reducing the spatters during short circuits and for stabilizing the beads by the periodic short circuits. However, an increase of deposition amount in response to the speed is required for the high-speed welding. Large-current low-spatter welding current region control was added. Units were integrated into a package by which the arc length is kept in short without dispersion of arc length for welding without defects such as undercut and unequal beads. In automobile industry, use of aluminum parts is extended for the light weight. The welding is very difficult, and automation is not so progressing in spite of the poor environment. Buckling of welding wire is easy to occur, and supply of wire is obstructed by the deposition of chipped powders on the torch cable, which stay within the contact chip resulting in the deposition. Dislocation of locus is easy to occur at the corner of rectangular pipe during the welding. By improving these troubles, an aluminum MIG welding robot package has been developed. 13 figs.

Developing new markets for oil sands products

International Nuclear Information System (INIS)

Crandall, G.

2004-01-01

This paper presents a review by Purvin and Gertz of western Canadian crude oil supply. This energy consulting firm provides advise to the energy sector. It suggests that oil sands production will surpass declining conventional production. Oil sands supply includes bitumen, synthetic crude oil (SCO), and diluent. It is forecasted that oil sands will increase from 42 per cent of western supply in 2002 to 78 per cent in 2015. The potential of Alberta's oil sands was discussed along with a recent study of refined products and petrochemicals from bitumen. Upgrading, refining and petrochemical case studies were presented. The author examined if a Canadian oil sands upgrading project with high capital costs can be competitive with competing projects in the United States and internationally. In addition to supply and demand issues, the presentation examined infrastructure capability and market potential in the United States. The economic potential and risks of preferred business cases compared to upgrading to SCO were also evaluated. 15 figs

A Brief Introduction to the Theory of Friction Stir Welding

Science.gov (United States)

Nunes, Arthur C., Jr.

2008-01-01

Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and is already an important welding process for the aerospace industry, where welds of optimal quality are demanded. The structure of welds determines weld properties. The structure of friction stir welds is determined by the flow field in the weld metal in the vicinity of the weld tool. A simple kinematic model of the FSW flow field developed at Marshall Space Flight Center, which enables the basic features of FSW microstructure to be understood and related to weld process parameters and tool design, is explained.

Effect of tool shape and welding parameters on mechanical properties and microstructure of dissimilar friction stir welded aluminium alloys

Directory of Open Access Journals (Sweden)

Chetan Aneja

2016-07-01

Full Text Available In the present experimental study, dissimilar aluminum alloy AA5083 and AA6082 were friction stir welded by varying tool shape, welding speed and rotary speed of the tool in order to investigate the effect of varying tool shape and welding parameters on the mechanical properties as well as microstructure. The friction stir welding (FSW process parameters have great influence on heat input per unit length of weld. The outcomes of experimental study prove that mechanical properties increases with decreasing welding speed. Furthermore mechanical properties were also found to improve as the rotary speed increases and the same phenomenon was found to happen while using straight cylindrical threaded pin profile tool. The microstructure of the dissimilar joints revealed that at low welding speeds, the improved material mixing was observed. The similar phenomenon was found to happen at higher rotational speeds using straight cylindrical threaded tool.

Welding of large-size embelled fittings in NPP construction

International Nuclear Information System (INIS)

Semenov, N.A.; Savinov, O.A.

1988-01-01

Drawbacks of the accepted technology for peoducing embedded fittings are considered. Activities on modernization of the standard ADF-2001 automatic welding machine are described. Results of testing the samples of welded joints performed using the modernized automatic welding machine, and economic effect caused by its introduction at the balakovo NPP second unit construction are presented

Soldadura (Welding). Spanish Translations for Welding.

Science.gov (United States)

Hohhertz, Durwin

Thirty transparency masters with Spanish subtitles for key words are provided for a welding/general mechanical repair course. The transparency masters are on such topics as oxyacetylene welding; oxyacetylene welding equipment; welding safety; different types of welds; braze welding; cutting torches; cutting with a torch; protective equipment; arc…

Underwater laser beam welding of Alloy 690

International Nuclear Information System (INIS)

Hino, Takehisa; Tamura, Masataka; Kono, Wataru; Kawano, Shohei; Yoda, Masaki

2009-01-01

Stress Corrosion Clacking (SCC) has been reported at Alloy 600 welds between nozzles and safe-end in Pressurized Water Reactor (PWR) plant. Alloy 690, which has higher chromium content than Alloy 600, has been applied for cladding on Alloy 600 welds for repairing damaged SCC area. Toshiba has developed Underwater Laser Beam Welding technique. This method can be conducted without draining, so that the repairing period and the radiation exposure during the repair can be dramatically decreased. In some old PWRs, high-sulfur stainless steel is used as the materials for this section. It has a high susceptibility of weld cracks. Therefore, the optimum welding condition of Alloy 690 on the high-sulfur stainless steel was investigated with our Underwater Laser Beam Welding unit. Good cladding layer, without any crack, porosity or lack of fusion, could be obtained. (author)

MAGNETIC ARC WELDING STABILIZATION USING NON-CONSUMABLE ELECTRODE

Directory of Open Access Journals (Sweden)

Павло Юрійович Сидоренко

2017-06-01

Full Text Available Results of development torch to magnetically operated   welding arc are defined. Changing the design of the electrode unit is provided the ability to create within the area of the arc magnetic field and induction given configuration without additional equipment. The features of the arc in an axial magnetic field which make it possible to avoid the welding process of unsteady abnormalities resulted in the inappropriate formation of defects in welds. Significant increase in the depth of  weld penetration is connected with the more concentrated magnetically operated   welding arc transmission energy to the product. It is concluded about the feasibility of using a designed torch for the implementation of modern technological processes non-consumable electrode welding.

Oxide induced corrosion on the welded stainless steels SS 2352 and 2353

International Nuclear Information System (INIS)

Stroem, S.; Li Huiqin.

1991-01-01

The pitting corrosion properties have been investigated in welded and unwelded condition by polarization tests in sodium chloride solutions. The two steels were TIG welded without adding welding material and as shielding on the bottom side argon gas containing 2, 26 or 99 ppm oxygen was used. In some tests low breakthrough potentials were received, without discovering any pitting corrosion in the specimen surfaces. The unwelded SS 2352 steel had a critical (lowest) pitting temperature (CPT) of 5 degrees C in the more concentrated solution. For the same steel with weld pitting corrosion was obtained at 5 degrees C, which was the lowest temperature for the tests. Thus the CPT value was lower than 5 degrees C, but by looking at the pitting corrosion potentials the following conclusion could be drawn: Welding with higher oxygen content in the shielding gas implied lower pitting corrosion resistance. For the SS 2353 steel the CPT values were 25 and 27.5 degrees C for material without weld, in contact with the more concentrated and the more dilute solution respectively. Welded material was all through more sensitive to pitting corrosion, and the CPT values were 15-17.5, 15 and 5-10 degrees C for welded areas which had been gas shielded with argon containing 2, 26 and 99 ppm oxygen respectively. The result thus showed that welding with shielding gas containing maximum about 30 ppm oxygen does not substantially affect the pitting corrosion properties. Post treatment of the welding areas increased the pitting corrosion resistance. Acid pickling implied the highest pitting corrosion resistance with 15 degrees C as CPT value for the 2353 steel in the more concentrated solution. Steel brushing implied an obvious increase to the pitting corrosion resistance compared to untreated weld areas and the same statement could be done for sand blasted surfaces. (10 refs., 16 tabs., 11 figs.)

Western Gas Sands Project. Status report, 1 March 1979--31 March 1979

Energy Technology Data Exchange (ETDEWEB)

None

1979-01-01

Progress of the government-sponsored projects directed toward increasing gas production from low-permeability gas sands of the western United States is summarized. During March, National Laboratories and Energy Technology Centers generally progressed on schedule. Bartlesville Energy Technology Center continued work on fracture conductivity, rock-fluid interaction, and log evaluation techniques. Theoretical and experimental work on hydraulic fracturing mechanics and analysis of well test data continued at Lawrence Livermore Laboratory. Sandia Laboratories completed preparations for the NTS evaluation test of the borehole seismic system. M.D. Wood, Inc. monitored the formation of a hydraulic fracture in the Wattenburg gas field, Weld County, Colorado. Measurement of bottom-hole pressure in the Miller No. 1 and Sprague No. 1 wells for the CIG cyclic gas injection project continued. The Mitchell Energy Corporation Muse--Duke No. 1 was flowing 4,000 MCFD in March. Efforts to clean out Mobil's PCU F31-13G well continued.

Direct Chlorination of Zircon Sand

International Nuclear Information System (INIS)

Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

2002-01-01

It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

Ultrasonic testing of electron beam closure weld on pressure vessel

International Nuclear Information System (INIS)

Andrews, R.W.

1975-01-01

One of the special products manufactured at the General Electric Neutron Devices Department (GEND) is a small stainless steel vessel designed to hold a component under high pressure for long periods. The vessel is a thick-walled cylinder with a threaded receptacle into which a plug is screwed and welded after receiving the unit to be tested. The test cavity is then pressurized through a small diameter opening in the bottom and that opening is welded closed. When x-ray inspection techniques did not reveal defective welds at the threaded plug in a pressured vessel, occasional ''leakers'' occurred. With normal equipment tolerances, the electron beam spike tends to wander from the desired path, particularly at the root of the weld. Ultrasonic techniques were used to successfully inspect the weld. The testing technique is based on the observation that ultrasonic energy is reflected from the unwelded screw threads and not from the regions where the threads are completely fused together by welding. Any gas pore or any threaded region outside the weld bead can produce an echo. The units are rotated while the ultrasonic transducer travels in a direction parallel to the axis of rotation and toward the welded end. This produces a helical scan which is converted to a two-dimensional presentation in which incomplete welds can be noted. (U.S.)

Structure and properties of fixed joints formed by ultrasonic-assisted friction-stir welding

Energy Technology Data Exchange (ETDEWEB)

Fortuna, S. V., E-mail: s-fortuna@ispms.ru; Ivanov, K. V., E-mail: ikv@ispms.ru; Eliseev, A. A., E-mail: alan@ispms.ru [Institute of Strength Physics and Materials ScienceTomsk, 634055 (Russian Federation); Tarasov, S. Yu., E-mail: tsy@ispms.ru; Ivanov, A. N., E-mail: ivan@ispms.ru; Rubtsov, V. E., E-mail: rvy@ispms.ru; Kolubaev, E. A., E-mail: eak@ispms.ru [Institute of Strength Physics and Materials ScienceTomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

2015-10-27

This paper deals with structure and properties of aluminum alloy 7475 and its joints obtained by friction stir welding including under ultrasonic action. Microhardness measurements show that ultrasonic action increases strength properties of the joints. Optical and transmission electron microscopy reveals that this effect is related to the precipitation of tertiary coherent S-and T-phase particles.

Sand and Gravel Operations

Data.gov (United States)

Department of Homeland Security — This map layer includes sand and gravel operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...

Mineral Resource Assessment of Marine Sand Resources in Cape- and Ridge-Associated Marine Sand Deposits in Three Tracts, New York and New Jersey, United States Atlantic Continental Shelf

Science.gov (United States)

Bliss, James D.; Williams, S. Jeffress; Arsenault, Matthew A.

2009-01-01

Demand is growing in the United States and worldwide for information about the geology of offshore continental shelf regions, the character of the seafloor, and sediments comprising the seafloor and subbottom. Interest in locating sand bodies or high quality deposits that have potential as sources for beach nourishment and ecosystem restoration is especially great in some regions of the country. The Atlantic coast, particularly New York and New Jersey, has been the focus of these studies for the past 40 years with widely varying results. This study is the first attempt at applying probability statistics to modeling Holocene-age cape-and ridge-associated sand deposits and thus focuses on distinct sand body morphology. This modeling technique may have application for other continental shelf regions that have similar geologic character and late Quaternary sea-level transgression history. An estimated volume of 3.9 billion m3 of marine sand resources is predicted in the cape-and ridge-associated marine sand deposits in three representative regions or tracts on the continental shelf offshore of New York and New Jersey. These estimates are taken from probabilistic distributions of sand resources and are produced using deposit models and Monte Carlo Simulation (MCS) techniques. The estimated sand resources presented here are for only three tracts as described below and for Holocene age sand resources contained in cape-and ridge-associated marine sand deposit types within this area. Other areas may qualify as tracts for this deposit type and other deposit types and geologic ages (for example, paleo-stream channels, blanket and outwash deposits, ebb-tide shoals, and lower sea level-stand deltas), which are present on the New Jersey and New York continental shelf area but are not delineated and modeled in this initial evaluation. Admittedly, only a portion of these probable sand resources will ultimately be available and suitable for production, dependent largely on

Nondestructive testing of welds on thin-walled tubing

Science.gov (United States)

Hagemaier, D. J.; Posakony, G. J.

1969-01-01

Special ultrasonic search unit, or transducer assembly, reliably inspects the quality of melt-through welds of fusion welded tubing couplers for hydraulic lines. This instrumentation can also be used to detect faulty braze bonds in thin-walled, small diameter joints and wall thickness of thin-walled metal tubing.

Alberta oil sands royalty regime

International Nuclear Information System (INIS)

Asgarpour, S.

2004-01-01

The long term objective of the Oil Sands Business Unit of Alberta Energy is to pave the way for Alberta's bitumen production to reach 3 million barrels per day by 2020. This presentation described the national government's role in resource development. It was emphasized that since the Crown is the owner of the oil sands resource, it would benefit by providing strategic leadership and by generating a larger royalty base. The oil sands fiscal regime was described with reference to generic royalty, risk sharing, investment, and project economics. Business rule principles were also outlined along with criteria for project expansions. Both upstream and downstream challenges and opportunities were listed. 4 figs

Value of Canadian oil sands... to the United States

International Nuclear Information System (INIS)

Pugliaresi, Lucian

2011-01-01

Since the beginning of the recession in late 2007, the American economy has been subject to great change, affecting the way energy is produced and consumed. The structure of oil imports and exports has changed significantly and U.S. imports are now primarily from Canada. The current study shows how and why the U.S. has become dependent on imports of oil from the Canadian oil sands. Oil from Canadian oil sands is transported to different Petroleum Administration for Defense Districts (PADD) via the Keystone pipeline. As imports from Canada increased, the U.S. refinery sector was restructured. Small refineries were closed while larger refineries were expanded and investment was made to increase their processing capacity. The increased import and processing of oil from the Canadian oil sands led to an advantageous decrease in oil prices. If the Keystone XL project were to be approved, the pipeline would increase the area with access to the means of transporting oil, allowing the increasing demand for oil to be met and, potentially, stabilizing world oil prices.

Effects on the efficiency of activated carbon on exposure to welding fumes

Energy Technology Data Exchange (ETDEWEB)

Ghosh, D. [Southern Company Services, Inc., Birmingham, AL (United States)

1995-02-01

It is the intention of this paper to document that certain types of welding fumes have little or no effect on the effectiveness of the carbon filter air filtration efficiency when directly exposed to a controlled amount of welding fumes for a short-term period. The welding processes studied were restricted to shielded metal arc welding (SMAW), flux cored arc welding (FCAW), gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) processes. Contrary to the SMAW and FCAW processes, the GTAW (or TIG) and the GMAW (or MIG) welding processes do not require the use of flux as part of the overall process. Credit was taken for these processes occurring in inert gas environments and producing minimal amount of smoke. It was concluded that a study involving the SMAW process would also envelop the effects of the TIG and MIG welding processes. The quantity of welding fumes generated during the arc welding process is a function of the particular process, the size and type of electrode, welding machine amperage, and operator proficiency. For this study, the amount of welding for specific testing was equated to the amount of welding normally conducted during plant unit outages. Different welding electrodes were also evaluated, and the subsequent testing was limited to an E7018 electrode which was judged to be representative of all carbon and stainless steel electrodes commonly used at the site. The effect of welding fumes on activated charcoal was tested using a filtration unit complete with prefilters, upstream and downstream high efficiency particulate air (HEPA) filters, and a carbon adsorber section. The complete system was field tested in accordance with ANSI N510 standards prior to exposing the filters and the adsorber bed to welding fumes. The carbon samples were tested at an established laboratory using ASTM D3803-1989 standards.

Titanium mineral resources in heavy-mineral sands in the Atlantic coastal plain of the southeastern United States

Science.gov (United States)

Van Gosen, Bradley S.; Ellefsen, Karl J.

2018-04-16

This study examined titanium distribution in the Atlantic Coastal Plain of the southeastern United States; the titanium is found in heavy-mineral sands that include the minerals ilmenite (Fe2+TiO3), rutile (TiO2), or leucoxene (an alteration product of ilmenite). Deposits of heavy-mineral sands in ancient and modern coastal plains are a significant feedstock source for the titanium dioxide pigments industry. Currently, two heavy-mineral sands mining and processing operations are active in the southeast United States producing concentrates of ilmenite-leucoxene, rutile, and zircon. The results of this study indicate the potential for similar deposits in many areas of the Atlantic Coastal Plain.This study used the titanium analyses of 3,457 stream sediment samples that were analyzed as part of the U.S. Geological Survey’s National Geochemical Survey program. This data set was analyzed by an integrated spatial modeling technique known as Bayesian hierarchical modeling to map the regional-scale, spatial distribution of titanium concentrations. In particular, clusters of anomalous concentrations of titanium occur: (1) along the Fall Zone, from Virginia to Alabama, where metamorphic and igneous rocks of the Piedmont region contact younger sediments of the Coastal Plain; (2) a paleovalley near the South Carolina and North Carolina border; (3) the upper and middle Atlantic Coastal Plain of North Carolina; (4) the majority of the Atlantic Coastal Plain of Virginia; and (5) barrier islands and stretches of the modern shoreline from South Carolina to northeast Florida. The areas mapped by this study could help mining companies delimit areas for exploration.

Advances in automatic welding control

International Nuclear Information System (INIS)

White, D.; Woodacre, A.; Taylor, A.F.

1972-01-01

The development at the Reactor Fuel Element Laboratories, UKAEA Springfields, of a computer-based welding process control system, was aimed initially at the TIG welding of the end seals of nuclear fuel elements. The system provides for mixed multi-station operation with on-line real-time capability and can be used either as a research tool or for production requirements at competitive costs. The operation of the control system, the form of power source, and the servo motor control units are described. Typically, continuous or pulse-arc welding sequences can be digitally programmed on 0.1 sec increments, with current in 0.5 A increments up to a maximum of 256 A; up to three servo motors can be operated with speeds selected in 0.1 percent increments of their maximum. Up to six welding parameters can be monitored digitally at speeds from once every 10 msec. Some applications are described and it is shown that the equipment has wider uses outside the nuclear fuel element field. High quality industrial welding requirements can also be met and the system is not limited to the TIG process

Advances in automatic welding control

International Nuclear Information System (INIS)

White, D.; Woodacre, A.; Taylor, A.F.

1972-01-01

The development at the Reactor Fuel Element Laboratories, UKAEA Springfields, of a computer-based welding process control system, was aimed initially at the TIG welding of the end seals of nuclear fuel elements. The system provides for mixed multi-station operation with on-line real-time capability and can be used either as a research tool or for production requirements at competitive costs. The operation of the control system, the form of power source and servo motor control units are described. Typically, continuous or pulse-arc welding sequences can be digitally programmed on 0.1 sec increments, with current in 0.5 A increments up to a maximum of 256 A; up to three servo motors can be operated with speeds selected in 0.1% increments of their maximum. Up to six welding parameters can be monitored digitally at speeds from once every 10 msec. Some applications are described and it is shown that the equipment has wider uses outside the nuclear fuel element field. High quality industrial welding requirements can also be met and the system is not limited to the TIG process. (author)

FRICTION - WELDING MACHINE AUTOMATIC CONTROL CIRCUIT DESIGN AND APPLICATION

OpenAIRE

Hakan ATEŞ; Ramazan BAYINDIR

2003-01-01

In this work, automatic controllability of a laboratory-sized friction-welding machine has been investigated. The laboratory-sized friction-welding machine was composed of motor, brake, rotary and constant samples late pliers, and hydraulic unit. In automatic method, welding parameters such as friction time, friction pressure, forge time and forge pressure can be applied sensitively using time relays and contactors. At the end of the experimental study it's observed that automatic control sys...

Occupational noise-induced hearing loss in auto part factory workers in welding units in Thailand.

Science.gov (United States)

Sriopas, Apiradee; Chapman, Robert S; Sutammasa, Saravudh; Siriwong, Wattasit

2017-01-24

Most workers in auto part factories in Thailand are usually exposed to excessive noise in their workplace. This study aimed to assess the level of occupational noise-induced hearing loss and investigate risk factors causing hearing loss in auto part factory workers in the welding units in Thailand. This was a cross-sectional study. One hundred eighty subjects were recruited from 356 workers in the welding unit of three factories. Sixty eligible subjects in each factory were selected by systemic random sampling. The subjects were interviewed using a face-to-face questionnaire. Noise exposure levels and audiograms were measured by a noise dosimeter and an audiometer, respectively. The findings confirmed that noise exposure levels of 86-90 dB (A) and exceeding 90 dB (A) significantly increased the risk of hearing loss in either ear. A noise exposure level exceeding 90 dB (A) significantly increased the prevalence of hearing loss in both ears. Regarding, a 10-pack-year smoking history increased the prevalence of hearing loss in either ear or both ears. In addition, subjects with employment duration exceeding 10 years significantly developed hearing loss in either ear. The engineering control or personal control by wearing hearing protection device should be used to decrease noise exposure levels lower than 85 dB (A) for 8 h. Moreover, if the exposure level reaches 85 dB (A) for 8 h, the employer needs to implement a hearing conservation program in the workplace.

Appraisal of the tight sands potential of the Sand Wash and Great Divide Basins

International Nuclear Information System (INIS)

1993-08-01

The volume of future tight gas reserve additions is difficult to estimate because of uncertainties in the characterization and extent of the resource and the performance and cost-effectiveness of stimulation and production technologies. Ongoing R ampersand D by industry and government aims to reduce the risks and costs of producing these tight resources, increase the certainty of knowledge of their geologic characteristics and extent, and increase the efficiency of production technologies. Some basins expected to contain large volumes of tight gas are being evaluated as to their potential contribution to domestic gas supplies. This report describes the results of one such appraisal. This analysis addresses the tight portions of the Eastern Greater Green River Basin (Sand Wash and Great Divide Subbasins in Northwestern Colorado and Southwestern Wyoming, respectively), with respect to estimated gas-in-place, technical recovery, and potential reserves. Geological data were compiled from public and proprietary sources. The study estimated gas-in-place in significant (greater than 10 feet net sand thickness) tight sand intervals for six distinct vertical and 21 areal units of analysis. These units of analysis represent tight gas potential outside current areas of development. For each unit of analysis, a ''typical'' well was modeled to represent the costs, recovery and economics of near-term drilling prospects in that unit. Technically recoverable gas was calculated using reservoir properties and assumptions about current formation evaluation and extraction technology performance. Basin-specific capital and operating costs were incorporated along with taxes, royalties and current regulations to estimate the minimum required wellhead gas price required to make the typical well in each of unit of analysis economic

Residual Stress Evaluation of Weld Inlay Process on Reactor Vessel Nozzles

Energy Technology Data Exchange (ETDEWEB)

Cho, Kihyun; Cho, Hong Seok [KEPCO KPS, Naju (Korea, Republic of)

2015-10-15

Weld overlay, weld inlay and stress improvement are mitigation technologies for butt joints. Weld overlay is done on pressurizer nozzles which are the highest potential locations occurring PWSCC due to high temperature in Korea. Reactor vessel nozzles are other big safety concerns for butt joints. Weld overlay and stress improvement should be so difficult to apply to those locations because space is too limited. Weld inlay should be one of the solutions. KEPCO KPS has developed laser welding system and process for reactor nozzles. Welding residual stress analysis is necessary for flaw evaluation. United States nuclear regulatory commission has calculated GTAW(Gas Tungsten Arc Welding) residual stress using ABAQUS. To confirm effectiveness of weld inlay process, welding residual stress analysis was performed. and difference between GTAW and LASER welding process was compared. Evaluation of weld inlay process using ANSYS and ABAQUS is performed. All of the both results are similar. The residual stress generated after weld inlay was on range of 450-500 MPa. Welding residual stresses are differently generated by GTAW and LASER welding. But regardless of welding process type, residual tensile stress is generated on inside surface.

Prediction of Weld Residual Stress of Narrow Gap Welds

International Nuclear Information System (INIS)

Yang, Jun Seog; Huh, Nam Su

2010-01-01

The conventional welding technique such as shield metal arc welding has been mostly applied to the piping system of the nuclear power plants. It is well known that this welding technique causes the overheating and welding defects due to the large groove angle of weld. On the other hand, the narrow gap welding(NGW) technique has many merits, for instance, the reduction of welding time, the shrinkage of weld and the small deformation of the weld due to the small groove angle and welding bead width comparing with the conventional welds. These characteristics of NGW affect the deformation behavior and the distribution of welding residual stress of NGW, thus it is believed that the residual stress results obtained from conventional welding procedure may not be applied to structural integrity evaluation of NGW. In this paper, the welding residual stress of NGW was predicted using the nonlinear finite element analysis to simulate the thermal and mechanical effects of the NGW. The present results can be used as the important information to perform the flaw evaluation and to improve the weld procedure of NGW

Hydrogeologic characteristics and water quality of a confined sand unit in the surficial aquifer system, Hunter Army Airfield, Chatham County, Georgia

Science.gov (United States)

Gonthier, Gerard

2012-01-01

An 80-foot-deep well (36Q397, U.S. Geological Survey site identification 320146081073701) was constructed at Hunter Army Airfield to assess the potential of using the surficial aquifer system as a water source to irrigate a ballfield complex. A 300-foot-deep test hole was drilled beneath the ballfield complex to characterize the lithology and water-bearing characteristics of sediments above the Upper Floridan aquifer. The test hole was then completed as well 36Q397 open to a 19-foot-thick shallow, confined sand unit contained within the surficial aquifer system. A single-well, 24-hour aquifer test was performed by pumping well 36Q397 at a rate of 50 gallons per minute during July 13-14, 2011, to characterize the hydrologic properties of the shallow, confined sand unit. Two pumping events prior to the aquifer test affected water levels. Drawdown during all three pumping events and residual drawdown during recovery periods were simulated using the Theis formula on multiple changes in discharge rate. Simulated drawdown and residual drawdown match well with measured drawdown and residual drawdown using values of horizontal hydraulic conductivity and specific storage, which are typical for a confined sand aquifer. Based on the hydrologic parameters used to match simulated drawdown and residual drawdown to measured drawdown and residual drawdown, the transmissivity of the sand was determined to be about 400 feet squared per day. The horizontal hydraulic conductivity of the sand was determined to be about 20 feet per day. Analysis of a water-quality sample indicated that the water is suitable for irrigation. Sample analysis indicated a calcium-carbonate type water having a total dissolved solids concentration of 39 milligrams per liter. Specific conductance and concentrations of all analyzed constituents were below those that would be a concern for irrigation, and were below primary and secondary water-quality criteria levels.

Investigation on mechanical properties of welded material under different types of welding filler (shielded metal arc welding)

Science.gov (United States)

Tahir, Abdullah Mohd; Lair, Noor Ajian Mohd; Wei, Foo Jun

2018-05-01

The Shielded Metal Arc Welding (SMAW) is (or the Stick welding) defined as a welding process, which melts and joins metals with an arc between a welding filler (electrode rod) and the workpieces. The main objective was to study the mechanical properties of welded metal under different types of welding fillers and current for SMAW. This project utilized the Design of Experiment (DOE) by adopting the Full Factorial Design. The independent variables were the types of welding filler and welding current, whereas the other welding parameters were fixed at the optimum value. The levels for types of welding filler were by the models of welding filler (E6013, E7016 and E7018) used and the levels for welding current were 80A and 90A. The responses were the mechanical properties of welded material, which include tensile strength and hardness. The experiment was analyzed using the two way ANOVA. The results prove that there are significant effects of welding filler types and current levels on the tensile strength and hardness of the welded metal. At the same time, the ANOVA results and interaction plot indicate that there are significant interactions between the welding filler types and the welding current on both the hardness and tensile strength of the welded metals, which has never been reported before. This project found that when the amount of heat input with increase, the mechanical properties such as tensile strength and hardness decrease. The optimum tensile strength for welded metal is produced by the welding filler E7016 and the optimum of hardness of welded metal is produced by the welding filler E7018 at welding current of 80A.

Development of underwater YAG laser repair welding robots for tanks

International Nuclear Information System (INIS)

Miwa, Yasuhiro; Satoh, Syuichi; Ito, Kosuke; Kochi, Tsutomu; Kojima, Toshio; Ohwaki, Katsura; Morita, Ichiro

1999-01-01

A remote-controlled repair welding robot which uses YAG laser welding technology in underwater environment was developed. This is an underwater robot technology combined with a laser welding technology. This report will describe the structure and performance of this robot, and the welding test results. The repair welding robot consists of two parts. The one is driving equipment, and the other is welding unit. It can swim in the tank, move around the tank wall, and stay on the welding area. After that it starts YAG laser repair welding. The target of this technology is inner surface repair of some tanks made of austenitic stainless steel, for example RW (Radioactive Waste) tanks. A degradation by General Corrosion and so on might be occurred at inner surface of these tanks in BWR type nuclear power plants. If the damaged area is wide, repair welding works are done. Some workers go into the tank and set up scaffolding after full drainage. In many cases it spends too much time for draining water and repair welding preparation. If the repair welding works can be done in underwater environment, the outage period will be reduced. This is a great advantage. (author)

FRICTION - WELDING MACHINE AUTOMATIC CONTROL CIRCUIT DESIGN AND APPLICATION

Directory of Open Access Journals (Sweden)

Hakan ATEŞ

2003-02-01

Full Text Available In this work, automatic controllability of a laboratory-sized friction-welding machine has been investigated. The laboratory-sized friction-welding machine was composed of motor, brake, rotary and constant samples late pliers, and hydraulic unit. In automatic method, welding parameters such as friction time, friction pressure, forge time and forge pressure can be applied sensitively using time relays and contactors. At the end of the experimental study it's observed that automatic control system has been worked successfully.

Influence green sand system by core sand additions

Directory of Open Access Journals (Sweden)

N. Špirutová

2012-01-01

Full Text Available Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?”This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition. Ratio of active betonite by Methylene blue test was also determined.

The optimal parameter design for a welding unit of manufacturing industry by Taguchi method and computer simulation

Energy Technology Data Exchange (ETDEWEB)

Zahraee, S.M.; Chegeni, A.; Toghtamish, A.

2016-07-01

Manufacturing systems include a complicated combination of resources, such as materials, labors, and machines. Hence, when the manufacturing systems are faced with a problem related to the availability of resources it is difficult to identify the root of the problem accurately and effectively. Managers and engineers in companies are trying to achieve a robust production line based on the maximum productivity. The main goal of this paper is to design a robust production line, taking productivity into account in the selected manufacturing industry. This paper presents the application of Taguchi method along with computer simulation for finding an optimum factor setting for three controllable factors, which are a number of welding machines, hydraulic machines, and cutting machines by analyzing the effect of noise factors in a selected manufacturing industry. Based on the final results, the optimal design parameter of welding unit of in the selected manufacturing industry will be obtained when factor A is located at level 2 and B and C are located at level 1. Therefore, maximum productive desirability is achieved when the number of welding machines, hydraulic machines, and cutting machines is equal to 17, 2, and 1, respectively. This paper has a significant role in designing a robust production line by considering the lowest cost and timely manner based on the Taguchi method. (Author)

The optimal parameter design for a welding unit of manufacturing industry by Taguchi method and computer simulation

Directory of Open Access Journals (Sweden)

Seyed Mojib Zahraee

2016-05-01

Full Text Available Purpose: Manufacturing systems include a complicated combination of resources, such as materials, labors, and machines. Hence, when the manufacturing systems are faced with a problem related to the availability of resources it is difficult to identify the root of the problem accurately and effectively. Managers and engineers in companies are trying to achieve a robust production line based on the maximum productivity. The main goal of this paper is to design a robust production line, taking productivity into account in the selected manufacturing industry. Design/methodology/approach: This paper presents the application of Taguchi method along with computer simulation for finding an optimum factor setting for three controllable factors, which are a number of welding machines, hydraulic machines, and cutting machines by analyzing the effect of noise factors in a selected manufacturing industry. Findings and Originality/value: Based on the final results, the optimal design parameter of welding unit of in the selected manufacturing industry will be obtained when factor A is located at level 2 and B and C are located at level 1. Therefore, maximum productive desirability is achieved when the number of welding machines, hydraulic machines, and cutting machines is equal to 17, 2, and 1, respectively. This paper has a significant role in designing a robust production line by considering the lowest cost and timely manner based on the Taguchi method.

Microhardness Testing of Aluminum Alloy Welds

Science.gov (United States)

Bohanon, Catherine

2009-01-01

A weld is made when two pieces of metal are united or fused together using heat or pressure, and sometimes both. There are several different types of welds, each having their own unique properties and microstructure. Strength is a property normally used in deciding which kind of weld is suitable for a certain metal or joint. Depending on the weld process used and the heat required for that process, the weld and the heat-affected zone undergo microstructural changes resulting in stronger or weaker areas. The heat-affected zone (HAZ) is the region that has experienced enough heat to cause solid-state microstructural changes, but not enough to melt the material. This area is located between the parent material and the weld, with the grain structure growing as it progresses respectively. The optimal weld would have a short HAZ and a small fluctuation in strength from parent metal to weld. To determine the strength of the weld and decide whether it is suitable for the specific joint certain properties are looked at, among these are ultimate tensile strength, 0.2% offset yield strength and hardness. Ultimate tensile strength gives the maximum load the metal can stand while the offset yield strength gives the amount of stress the metal can take before it is 0.2% longer than it was originally. Both of these are good tests, but they both require breaking or deforming the sample in some way. Hardness testing, however, provides an objective evaluation of weld strengths, and also the difference or variation in strength across the weld and HAZ which is difficult to do with tensile testing. Hardness is the resistance to permanent or plastic deformation and can be taken at any desired point on the specimen. With hardness testing, it is possible to test from parent metal to weld and see the difference in strength as you progress from parent material to weld. Hardness around grain boundaries and flaws in the material will show how these affect the strength of the metal while still

Weld Nugget Temperature Control in Thermal Stir Welding

Science.gov (United States)

Ding, R. Jeffrey (Inventor)

2014-01-01

A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

Automatic weld joint X-ray inspection

International Nuclear Information System (INIS)

Richter, H.U.; Linke, D.; Siems, K.D.; Kruse, H.; Schuetze, E.

1990-01-01

A gantry mounted robotic x-ray inspection unit has been developed for the series testing of small and medium sized welded components (pipe bends and nozzles). The unit features computer controlled positioning of the x-ray tube and x-ray image amplifier. Image quality classes 2 and even 1 could be achieved without difficulty. (author)

Transition welds in welding of two-ply steels

International Nuclear Information System (INIS)

Fartushnyj, V.G.; Evsyukov, Yu.G.

1977-01-01

Studied were physico-mechanical properties of welds made by various welding wires of chromium-nickel and nickel-chromium steels in submerged arc welding of double-layer steels with main layer of the VSt.3sp. carbon steel. It is shown that service-reliable structures welded of two-layer steels are obtained by providing the content from 11 to 20 % Ni in the automatically welded transition layer

Weld controller for automated nuclear service welding

International Nuclear Information System (INIS)

Barfield, K.L.; Strubhar, P.M.; Green, D.I.

1995-01-01

B and W Nuclear Technologies (BWNT) uses many different types of weld heads for automated welding in the commercial nuclear service industry. Some weld heads are purchased as standard items, while others are custom designed and fabricated by BWNT requiring synchronized multiaxis motion control. BWNT recently completed a development program to build a common weld controller that interfaces to all types of weld heads used by BWNT. Their goal was to construct a system that had the flexibility to add different modules to increase the capability of the controller as different application needs become necessary. The benefits from having a common controller are listed. This presentation explains the weld controller system and the types of applications to which it has been applied

Continuous fields of land cover for the conterminous United States using Landsat data: First results from the Web-Enabled Landsat Data (WELD) project

Science.gov (United States)

Hansen, M.C.; Egorov, Alexey; Roy, David P.; Potapov, P.; Ju, J.; Turubanova, S.; Kommareddy, I.; Loveland, Thomas R.

2011-01-01

Vegetation Continuous Field (VCF) layers of 30 m percent tree cover, bare ground, other vegetation and probability of water were derived for the conterminous United States (CONUS) using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data sets from the Web-Enabled Landsat Data (WELD) project. Turnkey approaches to land cover characterization were enabled due to the systematic WELD Landsat processing, including conversion of digital numbers to calibrated top of atmosphere reflectance and brightness temperature, cloud masking, reprojection into a continental map projection and temporal compositing. Annual, seasonal and monthly WELD composites for 2008 were used as spectral inputs to a bagged regression and classification tree procedure using a large training data set derived from very high spatial resolution imagery and available ancillary data. The results illustrate the ability to perform Landsat land cover characterizations at continental scales that are internally consistent while retaining local spatial and thematic detail.

Use of servo controlled weld head for end closure welding

Energy Technology Data Exchange (ETDEWEB)

Pathak, S.K.; Setty, D.S.; Rameswara Rao, A.; Hemantha Rao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderabad (India)

2010-07-01

In the PHWR fuel fabrication line resistance welding processes are used for joining various zirconium based alloy components to fuel tube of similar material. The quality requirement of these welding processes is very stringent and has to meet all the product requirements. At present these welding processes are being carried out by using standard resistance welding machines. In the resistance welding process in addition to current and time, force is one of the critical and important parameter, which influences the weld quality. At present advanced feed back type fast response medium frequency weld controllers are being used. This has upslope/down slope, constant and repetitive weld pattern selection features makes this critical welding process more reliable. Compared to weld controllers, squeeze force application devices are limited and normally standard high response pneumatic cylinders are used in the welding process. With this type of devices the force is constant during welding process and cannot be varied during welding process as per the material deformation characteristics. Similarly due to non-availability of feed back systems in the squeeze force application systems restricts the accuracy and quality of the welding process. In the present paper the influence of squeeze force pattern on the weld quality using advanced feed back type servo based force control system was studied. Different squeeze forces were used during pre and post weld heat periods along with constant force and compared with the weld quality. (author)

Effect of process parameters on optimum welding condition of DP590 steel by friction stir welding

Energy Technology Data Exchange (ETDEWEB)

Kim, Young Gon; Kim, Ji Sun; Kim, In Ju [Korea Institute of Industrial Technology, Gwangju (Korea, Republic of)

2014-12-15

In the automotive industry, vehicle weight reduction techniques have been actively studied to improve the rate of fuel consumption and to cope with the regulation restricting exhaust gas. For this reason, advanced high-strength steel (AHSS) is preferred in the automobile industry as its tensile strength is 590 MPa and over. In this study, to obtain the optimum welding condition, the friction stir welding (FSW) process applied to AHSS was considered. The FSW experiment was performed on a stir plate using a Si{sub 3}N{sub 4} tool and a 1.4-mm thick DP590 steel sheet manufactured by cold rolling. In addition, to investigate the temperature distribution of the advancing and retreating sides in the welding state, the tool rotation speed of 800 rpm, and the welding speed of 180 mm/min, a K-type thermocouple was inserted in the backing plate, and the peak temperature was evaluated at each point. Especially, the correlation between the heat input per unit length and the formation of the FSW zone was minutely analyzed.

Effect of process parameters on optimum welding condition of DP590 steel by friction stir welding

International Nuclear Information System (INIS)

Kim, Young Gon; Kim, Ji Sun; Kim, In Ju

2014-01-01

In the automotive industry, vehicle weight reduction techniques have been actively studied to improve the rate of fuel consumption and to cope with the regulation restricting exhaust gas. For this reason, advanced high-strength steel (AHSS) is preferred in the automobile industry as its tensile strength is 590 MPa and over. In this study, to obtain the optimum welding condition, the friction stir welding (FSW) process applied to AHSS was considered. The FSW experiment was performed on a stir plate using a Si 3 N 4 tool and a 1.4-mm thick DP590 steel sheet manufactured by cold rolling. In addition, to investigate the temperature distribution of the advancing and retreating sides in the welding state, the tool rotation speed of 800 rpm, and the welding speed of 180 mm/min, a K-type thermocouple was inserted in the backing plate, and the peak temperature was evaluated at each point. Especially, the correlation between the heat input per unit length and the formation of the FSW zone was minutely analyzed.

Contribution to the metallurgy of welding processes in stainless ferritic-austenitic (duplex) steels

International Nuclear Information System (INIS)

Perteneder, E.; Toesch, J.; Rabensteiner, G.

1989-01-01

Duplex steels have a ferritic austenitic structure. Therefore, to obtain a successful welding, special metallurgical regulations must be observed. The effect of energy per unit length and plate thickness onto the heat influence zone in case of manual arc welding is examined. Practice-oriented instructions for the welding technique to be applied are deduced from the results. Finally, the effect of the alloy composition onto the welding capacity of duplex steels is examined. (orig.) [de

Welding hazards

International Nuclear Information System (INIS)

Khan, M.A.

1992-01-01

Welding technology is advancing rapidly in the developed countries and has converted into a science. Welding involving the use of electricity include resistance welding. Welding shops are opened in residential area, which was causing safety hazards, particularly the teenagers and children who eagerly see the welding arc with their naked eyes. There are radiation hazards from ultra violet rays which irritate the skin, eye irritation. Welding arc light of such intensity could damage the eyes. (Orig./A.B.)

75 FR 53714 - Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan

Science.gov (United States)

2010-09-01

...)] Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan AGENCY: United States International... stainless steel butt-weld pipe fittings from Japan, Korea, and Taiwan. SUMMARY: The Commission hereby gives... butt-weld pipe fittings from Japan, Korea, and Taiwan would be likely to lead to continuation or...

Advanced Welding Concepts

Science.gov (United States)

Ding, Robert J.

2010-01-01

Four advanced welding techniques and their use in NASA are briefly reviewed in this poster presentation. The welding techniques reviewed are: Solid State Welding, Friction Stir Welding (FSW), Thermal Stir Welding (TSW) and Ultrasonic Stir Welding.

Resistance seam welding

International Nuclear Information System (INIS)

Schueler, A.W.

1977-01-01

The advantages and disadvantages of the resistance seam welding process are presented. Types of seam welds, types of seam welding machines, seam welding power supplies, resistance seam welding parameters and seam welding characteristics of various metals

Monitoring conterminous United States (CONUS) land cover change with Web-Enabled Landsat Data (WELD)

Science.gov (United States)

Hansen, M.C.; Egorov, Alexey; Potapov, P.V.; Stehman, S.V.; Tyukavina, A.; Turubanova, S.A.; Roy, David P.; Goetz, S.J.; Loveland, Thomas R.; Ju, J.; Kommareddy, A.; Kovalskyy, Valeriy; Forsyth, C.; Bents, T.

2014-01-01

Forest cover loss and bare ground gain from 2006 to 2010 for the conterminous United States (CONUS) were quantified at a 30 m spatial resolution using Web-Enabled Landsat Data available from the USGS Center for Earth Resources Observation and Science (EROS) (http://landsat.usgs.gov/WELD.php). The approach related multi-temporal WELD metrics and expert-derived training data for forest cover loss and bare ground gain through a decision tree classification algorithm. Forest cover loss was reported at state and ecoregional scales, and the identification of core forests' absent of change was made and verified using LiDAR data from the GLAS (Geoscience Laser Altimetry System) instrument. Bare ground gain correlated with population change for large metropolitan statistical areas (MSAs) outside of desert or semi-desert environments. GoogleEarth™ time-series images were used to validate the products. Mapped forest cover loss totaled 53,084 km2 and was found to be depicted conservatively, with a user's accuracy of 78% and a producer's accuracy of 68%. Excluding errors of adjacency, user's and producer's accuracies rose to 93% and 89%, respectively. Mapped bare ground gain equaled 5974 km2 and nearly matched the estimated area from the reference (GoogleEarth™) classification; however, user's (42%) and producer's (49%) accuracies were much less than those of the forest cover loss product. Excluding errors of adjacency, user's and producer's accuracies rose to 62% and 75%, respectively. Compared to recent 2001–2006 USGS National Land Cover Database validation data for forest loss (82% and 30% for respective user's and producer's accuracies) and urban gain (72% and 18% for respective user's and producer's accuracies), results using a single CONUS-scale model with WELD data are promising and point to the potential for national-scale operational mapping of key land cover transitions. However, validation results highlighted limitations, some of which can be addressed by

Revegetation and management of tailings sand slopes from tar sand extraction: 1978 results

Energy Technology Data Exchange (ETDEWEB)

Rowell, M J

1979-01-01

The results are reported of research into the revegetation of two areas on a steeply sloping dike composed of tailings sand from tar sand extraction at the Great Canadian Oil Sand Limited plant at Fort McMurray, Alberta. One area was seeded with three pasture grasses and two legumes in 1971 after the slope surface had been mixed with peat to a depth of 15 cm. A second area had been amended with peat or peat and overburden and differing rates of fertilizer added. A mix containing nine grasses, four legumes, and oats, as a companion crop, was seeded in July 1976. The objectives of the research were to study methods for the establishment of a stable vegetative cover that would prevent erosion of the slope and, in time, might become a self maintaining unit. Tillage of soil amendments to a depth of 15 cm and 30 cm were compared in promoting deeper rooting and stabilizing of the slope.

Fundamentals of Welding. Teacher Edition.

Science.gov (United States)

Fortney, Clarence; And Others

These instructional materials assist teachers in improving instruction on the fundamentals of welding. The following introductory information is included: use of this publication; competency profile; instructional/task analysis; related academic and workplace skills list; tools, materials, and equipment list; and 27 references. Seven units of…

Welding method, and welding device for use therein, and method of analysis for evaluating welds

NARCIS (Netherlands)

Aendenroomer, A.J.; Den Ouden, G.; Xiao, Y.H.; Brabander, W.A.J.

1995-01-01

Described is a method of automatically welding pipes, comprising welding with a pulsation welding current and monitoring, by means of a sensor, the variations occurring in the arc voltage caused by weld pool oscillations. The occurrence of voltage variations with only frequency components below 100

Comparison of Welding Residual Stresses of Hybrid Laser-Arc Welding and Submerged Arc Welding in Offshore Steel Structures

DEFF Research Database (Denmark)

Andreassen, Michael Joachim; Yu, Zhenzhen; Liu, Stephen

2016-01-01

In the offshore industry, welding-induced distortion and tensile residual stresses have become a major concern in relation to the structural integrity of a welded structure. Particularly, the continuous increase in size of welded plates and joints needs special attention concerning welding induced...... residual stresses. These stresses have a negative impact on the integrity of the welded joint as they promote distortion, reduce fatigue life, and contribute to corrosion cracking and premature failure in the weld components. This paper deals with the influence and impact of welding method on the welding...... induced residual stresses. It is also investigated whether the assumption of residual stresses up to yield strength magnitude are present in welded structures as stated in the design guidelines. The fatigue strength for welded joints is based on this assumption. The two welding methods investigated...

Oxyacetylene Welding and Oxyfuel Cutting. Third Edition. Teacher Edition [and] Student Edition [and] Student Workbook.

Science.gov (United States)

Knapp, John; Harper, Eddie

This Oklahoma curriculum guide, which includes a teacher edition, a student edition, and a student workbook, provides three units for a course on oxyacetylene welding, oxyfuel cutting, and cutting done with alternative fuels such as MAPP, propane, and natural gas. The three units are: "Oxyacetylene Welding"; "Oxyfuel Cutting";…

Influence of Processing Parameters on the Flow Path in Friction Stir Welding

Science.gov (United States)

Schneider, J. A.; Nunes, A. C., Jr.

2006-01-01

Friction stir welding (FSW) is a solid phase welding process that unites thermal and mechanical aspects to produce a high quality joint. The process variables are rpm, translational weld speed, and downward plunge force. The strain-temperature history of a metal element at each point on the cross-section of the weld is determined by the individual flow path taken by the particular filament of metal flowing around the tool as influenced by the process variables. The resulting properties of the weld are determined by the strain-temperature history. Thus to control FSW properties, improved understanding of the processing parameters on the metal flow path is necessary.

Welding technology transfer task/laser based weld joint tracking system for compressor girth welds

Science.gov (United States)

Looney, Alan

1991-01-01

Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

Mississippi Curriculum Framework for Welding (Program CIP: 48.0508--Welder/Welding Technologist). Secondary Programs.

Science.gov (United States)

Mississippi Research and Curriculum Unit for Vocational and Technical Education, State College.

This document, which reflects Mississippi's statutory requirement that instructional programs be based on core curricula and performance-based assessment, contains outlines of the instructional units required in local instructional management plans and daily lesson plans for welding I and II. Presented first are a program description and course…

Numerical analysis of weld pool oscillation in laser welding

Energy Technology Data Exchange (ETDEWEB)

Cho, Jung Ho [Chungbuk National University, Cheongju (Korea, Republic of); Farson, Dave F [The Ohio State University, Columbus (United States); Hollis, Kendall; Milewski, John O. [Los Alamos National Laboratory, Los Alamos (United States)

2015-04-15

Volume of fluid (VOF) numerical simulation was used to investigate melt flow and volumetric oscillation of conduction-mode pulsed laser weld pools. The result is compared to high speed video stream of titanium laser spot welding experiment. The total simulation time is 10ms with the first 5 ms being heating and melting under constant laser irradiation and the remaining 5 ms corresponding to resolidification of the weld pool. During the melting process, the liquid pool did not exhibit periodic oscillation but was continually depressed by the evaporation recoil pressure. After the laser pulse, the weld pool was excited into volumetric oscillation by the release of pressure on its surface and oscillation of the weld pool surface was analyzed. The simulation model suggested adjusting thermal diffusivity to match cooling rate and puddle diameter during solidification which is distinguishable from previous weld pool simulation. The frequency continuously increased from several thousand cycles per second to tens of thousands of cycles per second as the weld pool solidified and its diameter decreased. The result is the first trial of investigation of small weld pool oscillation in laser welding although there have been several reports about arc welding.

Alternate Welding Processes for In-Service Welding

Science.gov (United States)

2009-04-24

Conducting weld repairs and attaching hot tap tees onto pressurized pipes has the advantage of avoiding loss of service and revenue. However, the risks involved with in-service welding need to be managed by ensuring that welding is performed in a rep...

Hybrid laser-TIG welding, laser beam welding and gas tungsten arc welding of AZ31B magnesium alloy

International Nuclear Information System (INIS)

Liu Liming; Wang Jifeng; Song Gang

2004-01-01

Welding of AZ31B magnesium alloy was carried out using hybrid laser-TIG (LATIG) welding, laser beam welding (LBW) and gas tungsten arc (TIG) welding. The weldability and microstructure of magnesium AZ31B alloy welded using LATIG, LBW and TIG were investigated by OM and EMPA. The experimental results showed that the welding speed of LATIG was higher than that of TIG, which was caught up with LBW. Besides, the penetration of LATIG doubles that of TIG, and was four times that of LBW. In addition, arc stability was improved in hybrid of laser-TIG welding compared with using the TIG welding alone, especially at high welding speed and under low TIG current. It was found that the heat affect zone of joint was only observed in TIG welding, and the size of grains in it was evidently coarse. In fusion zone, the equiaxed grains exist, whose size was the smallest welded by LBW, and was the largest by TIG welding. It was also found that Mg concentration of the fusion zone was lower than that of the base one by EPMA in three welding processes

Development of Managing Program for Small Bore Piping Socket Weld on the Secondary System of NPP

International Nuclear Information System (INIS)

Lee, Dong Min; Ryu, Jong Myeong; Cho, Hong Seok; Cho, Ki Hyun; Choi, Sang Hoon; Kim, Man Hee

2011-01-01

Kori unit 3 had stopped operation due to leakage at steam generator drain line socket weld on June 6th, 2008. The cause of socket weld damage was known as welding defect and fatigue by vibration under normal operation. With above reason, the government has been required developing management program for small bore piping socket weld. Therefore, we have developed the socket weld management program to secure reliability and soundness of socket welds which are located at all domestic NPPs

Closing the weld gap with laser/mig hybrid welding process

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove; Wiwe, Bjarne David

2003-01-01

In this article, laboratory tests are demonstrated that systematically accesses the critical gap distance when welding CMn 2.13 mm steel with a 2.6 kW CO2 laser, combined with a MIG energy source. In the work, the welding speed is varied at gap distances from 0 to 0.8 mm such that the limits...... for obtaining sound welds are identified. The welds are quality assessed according to ISO 13.919-1 and EN25817, transversal hardness measurements are made and the heat input to the workpiece is calculated. The results show that the critical gap is 0.1 mm for a laser weld alone. With hybrid welding, this can...... be increased to 0.6 mm, even at a welding speed of 3.5 m/min. The maximum welding speed with the hybrid process is comparable to laser welding alone, 4.5 m/min. The measured hardness is comparable to MIG welding, and this corresponds to a 33 percent reduction compared to laser welding alone. The heat input...

Estimation of work capacity of welded mounting joints of pipelines of heat resisting steel

International Nuclear Information System (INIS)

Gorynin, I.V.; Ignatov, V.A.; Timofeev, B.T.; Blyumin, A.A.

1982-01-01

The analysis of a work capacity of circular welds made for the Dsub(y)850 pipeline connection with high pressure vessels of heat resisting steel of the 15Kh1NMFA type has been carried out on the base of test results with small samples and real units. Welds were performed using the manual electric arc welding without the following heat treatment. It has been shown that residual stresses in such welds do not produce an essential effect on the resistance of weld metal and heat affected zone on the formation and developments of cracks

LASER WELDING WITH MICRO-JET COOLING FOR TRUCK FRAME WELDING

Directory of Open Access Journals (Sweden)

Jan PIWNIK

2017-12-01

Full Text Available The aim of this paper is to analyse the mechanical properties of the weld steel structure of car body truck frames after laser welding. The best welding conditions involve the use of proper materials and alloy elements in steel and filer materials, in addition to welding technology, state of stress and temperature of exploitation. We present for the first time the properties of steel track structures after laser welding with micro-jet cooling. Therefore, good selection of both welding parameters and micro-jet cooling parameters is very important to achieve a proper steel structure. In this study, the metallographic structure, tensile results and impact toughness of welded joints have been analysed in terms of welding parameters.

Forming Completely Penetrated Welded T-joints when Pulsed Arc Welding

Science.gov (United States)

Krampit, N. Yu; Krampit, M. A.; Sapozhkov, A. S.

2016-04-01

The paper is focused on revealing the influence of welding parameters on weld formation when pulsed arc welding. As an experimental sample a T-joint over 10 mm was selected. Welding was carried out in flat position, which required no edge preparation but provided mono-directional guaranteed root penetration. The following parameters of welding were subjected to investigation: gap in the joint, wire feed rate and incline angles of the torch along and across the weld axis. Technological recommendations have been made with respect to pulsed arc welding; the cost price of product manufacturing can be reduced on their basis due to reduction of labor input required by machining, lowering consumption of welding materials and electric power.

In situ recovery of oil from Utah tar sand: a summary of tar sand research at the Laramie Energy Technology Center

Energy Technology Data Exchange (ETDEWEB)

Marchant, L.C.; Westhoff, J.D.

1985-10-01

This report describes work done by the United States Department of Energy's Laramie Energy Technology Center from 1971 through 1982 to develop technology for future recovery of oil from US tar sands. Work was concentrated on major US tar sand deposits that are found in Utah. Major objectives of the program were as follows: determine the feasibility of in situ recovery methods applied to tar sand deposits; and establish a system for classifying tar sand deposits relative to those characteristics that would affect the design and operation of various in situ recovery processes. Contents of this report include: (1) characterization of Utah tar sand; (2) laboratory extraction studies relative to Utah tar sand in situ methods; (3) geological site evaluation; (4) environmental assessments and water availability; (5) reverse combustion field experiment, TS-1C; (6) a reverse combustion followed by forward combustion field experiment, TS-2C; (7) tar sand permeability enhancement studies; (8) two-well steam injection experiment; (9) in situ steam-flood experiment, TS-1S; (10) design of a tar sand field experiment for air-stream co-injection, TS-4; (11) wastewater treatment and oil analyses; (12) economic evaluation of an in situ tar sand recovery process; and (13) appendix I (extraction studies involving Utah tar sands, surface methods). 70 figs., 68 tabs.

Resistance welding

DEFF Research Database (Denmark)

Bay, Niels; Zhang, Wenqi; Rasmussen, Mogens H.

2003-01-01

Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has changed...... this enabling prediction of the welding performance in details. The paper describes the programme in short and gives examples on industrial applications. Finally investigations of causes for failure in a complex industrial joint of two dissimilar metals are carried out combining numerical modelling...

Cu-Fe welding techniques by electromagnetic and electron beam welding processes

International Nuclear Information System (INIS)

Kumar, Satendra; Saroj, P.C.; Kulkarni, M.R.; Sharma, A.; Rajawat, R.K.; Saha, T.K.

2015-01-01

Electromagnetic welding being a solid state welding process has been found suitable for welding Copper and Iron which are conventionally very tricky. Owing to good electrical conductivity of both copper and iron, they are best suited combination for EM welding. For the experimental conditions presented above, 1.0 mm wall thickness of Cu tube was lap welded to Fe disc. A heavy duty four disc stainless steel coil was used for electromagnetic welding of samples. MSLD of the welded samples indicated leak proof joints. Metallographic examination of the welds also revealed defect free interfaces. Electron beam welding is also a non-conventional welding process used for joining dissimilar materials. Autogenous welding of the above specimen was carried out by EBW method for the sake of comparison. A characterization analysis of the above mentioned joining processes will be discussed in the paper. (author)

Deconvoluting the Friction Stir Weld Process for Optimizing Welds

Science.gov (United States)

Schneider, Judy; Nunes, Arthur C.

2008-01-01

In the friction stir welding process, the rotating surfaces of the pin and shoulder contact the weld metal and force a rotational flow within the weld metal. Heat, generated by the metal deformation as well as frictional slippage with the contact surface, softens the metal and makes it easier to deform. As in any thermo-mechanical processing of metal, the flow conditions are critical to the quality of the weld. For example, extrusion of metal from under the shoulder of an excessively hot weld may relax local pressure and result in wormhole defects. The trace of the weld joint in the wake of the weld may vary geometrically depending upon the flow streamlines around the tool with some geometry more vulnerable to loss of strength from joint contamination than others. The material flow path around the tool cannot be seen in real time during the weld. By using analytical "tools" based upon the principles of mathematics and physics, a weld model can be created to compute features that can be observed. By comparing the computed observations with actual data, the weld model can be validated or adjusted to get better agreement. Inputs to the model to predict weld structures and properties include: hot working properties ofthe metal, pin tool geometry, travel rate, rotation and plunge force. Since metals record their prior hot working history, the hot working conditions imparted during FSW can be quantified by interpreting the final microstructure. Variations in texture and grain size result from variations in the strain accommodated at a given strain rate and temperature. Microstructural data from a variety of FSWs has been correlated with prior marker studies to contribute to our understanding of the FSW process. Once this stage is reached, the weld modeling process can save significant development costs by reducing costly trial-and-error approaches to obtaining quality welds.

Effects of Fusion Tack Welds on Self-Reacting Friction Stir Welds

Science.gov (United States)

Nunes, A. C., Jr.; Pendleton, M. L.; Brooke, S. A.; Russell, C. K.

2012-01-01

In order to know whether fusion tack welds would affect the strength of self-reacting friction stir seam welds in 2195-T87 aluminum alloy, the fracture stresses of 144 tensile test coupons cut from 24 welded panels containing segments of friction stir welds were measured. Each of the panels was welded under unique processing conditions. A measure of the effect of the tack welds for each panel was devised. An analysis of the measures of the tack weld effect supported the hypothesis that fusion tack welds do not affect the strength of self-reacting friction stir welds to a 5% level of confidence.

Residual stress reduction in the penetration nozzle weld joint by overlay welding

International Nuclear Information System (INIS)

Jiang, Wenchun; Luo, Yun; Wang, B.Y.; Tu, S.T.; Gong, J.M.

2014-01-01

Highlights: • Residual stress reduction in penetration weld nozzle by overlay welding was studied. • The overlay weld can decrease the residual stress in the weld root. • Long overlay welding is proposed in the actual welding. • Overlay weld to decrease residual stress is more suitable for thin nozzle. - Abstract: Stress corrosion cracking (SCC) in the penetration nozzle weld joint endangers the structural reliability of pressure vessels in nuclear and chemical industries. How to decrease the residual stress is very critical to ensure the structure integrity. In this paper, a new method, which uses overlay welding on the inner surface of nozzle, is proposed to decrease the residual stresses in the penetration joint. Finite element simulation is used to study the change of weld residual stresses before and after overlay welding. It reveals that this method can mainly decrease the residual stress in the weld root. Before overlay welding, large tensile residual stresses are generated in the weld root. After overlay weld, the tensile hoop stress in weld root has been decreased about 45%, and the radial stress has been decreased to compressive stress, which is helpful to decrease the susceptibility to SCC. With the increase of overlay welding length, the residual stress in weld root has been greatly decreased, and thus the long overlay welding is proposed in the actual welding. It also finds that this method is more suitable for thin nozzle rather than thick nozzle

Welding processes handbook

CERN Document Server

Weman, Klas

2011-01-01

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

Welding Curriculum.

Science.gov (United States)

Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

This competency-based curriculum guide is a handbook for the development of welding trade programs. Based on a survey of Alaskan welding employers, it includes all competencies a student should acquire in such a welding program. The handbook stresses the importance of understanding the principles associated with the various elements of welding.…

Laser beam welding of titanium additive manufactured parts

OpenAIRE

Wits, Wessel Willems; Jauregui Becker, Juan Manuel

2015-01-01

In this paper the joinability of titanium Additive Manufactured (AM) parts is explored. Keyhole welding, using a pulsed laser beam, of conventionally produced parts is compared to AM parts. Metal AM parts are notorious for having remaining porosities and other non-isotropic properties due to the layered manufacturing process. This study shows that due to these deficiencies more energy per unit weld length is required to obtain a similar keyhole geometry for titanium AM parts. It is also demon...

LASER WELDING WITH MICRO-JET COOLING FOR TRUCK FRAME WELDING

OpenAIRE

Jan PIWNIK; Bożena SZCZUCKA-LASOTA; Tomasz WĘGRZYN; Wojciech MAJEWSKI

2017-01-01

The aim of this paper is to analyse the mechanical properties of the weld steel structure of car body truck frames after laser welding. The best welding conditions involve the use of proper materials and alloy elements in steel and filer materials, in addition to welding technology, state of stress and temperature of exploitation. We present for the first time the properties of steel track structures after laser welding with micro-jet cooling. Therefore, good selection of both welding paramet...

Thermal Stir Welding: A New Solid State Welding Process

Science.gov (United States)

Ding, R. Jeffrey

2003-01-01

Thermal stir welding is a new welding process developed at NASA's Marshall Space Flight Center in Huntsville, AL. Thermal stir welding is similar to friction stir welding in that it joins similar or dissimilar materials without melting the parent material. However, unlike friction stir welding, the heating, stirring and forging elements of the process are all independent of each other and are separately controlled. Furthermore, the heating element of the process can be either a solid-state process (such as a thermal blanket, induction type process, etc), or, a fusion process (YG laser, plasma torch, etc.) The separation of the heating, stirring, forging elements of the process allows more degrees of freedom for greater process control. This paper introduces the mechanics of the thermal stir welding process. In addition, weld mechanical property data is presented for selected alloys as well as metallurgical analysis.

Sustainability of Welding Process through Bobbin Friction Stir Welding

Science.gov (United States)

Sued, M. K.; Samsuri, S. S. M.; Kassim, M. K. A. M.; Nasir, S. N. N. M.

2018-03-01

Welding process is in high demand, which required a competitive technology to be adopted. This is important for sustaining the needs of the joining industries without ignoring the impact of the process to the environment. Friction stir welding (FSW) is stated to be benefitting the environment through low energy consumption, which cannot be achieved through traditional arc welding. However, this is not well documented, especially for bobbin friction stir welding (BFSW). Therefore, an investigation is conducted by measuring current consumption of the machine during the BFSW process. From the measurement, different phases of BFSW welding process and its electrical demand are presented. It is found that in general total energy in BFSW is about 130kW inclusive of all identified process phases. The phase that utilise for joint formation is in weld phase that used the highest total energy of 120kWs. The recorded total energy is still far below the traditional welding technology and the conventional friction stir welding (CFSW) energy demand. This indicates that BFSW technology with its vast benefit able to sustain the joining technology in near future.

Enabling high speed friction stir welding of aluminum tailor welded blanks

Science.gov (United States)

Hovanski, Yuri

Current welding technologies for production of aluminum tailor-welded blanks (TWBs) are utilized in low-volume and niche applications, and have yet to be scaled for the high-volume vehicle market. This study targeted further weight reduction, part reduction, and cost savings by enabling tailor-welded blank technology for aluminum alloys at high-volumes. While friction stir welding (FSW) has traditionally been applied at linear velocities less than one meter per minute, high volume production applications demand the process be extended to higher velocities more amenable to cost sensitive production environments. Unfortunately, weld parameters and performance developed and characterized at low to moderate welding velocities do not directly translate to high speed linear friction stir welding. Therefore, in order to facilitate production of high volume aluminum FSW components, parameters were developed with a minimum welding velocity of three meters per minute. With an emphasis on weld quality, welded blanks were evaluated for post-weld formability using a combination of numerical and experimental methods. Evaluation across scales was ultimately validated by stamping full-size production door inner panels made from dissimilar thickness aluminum tailor-welded blanks, which provided validation of the numerical and experimental analysis of laboratory scale tests.

Fully Automatic Spot Welding System for Application in Automotive Industry

Directory of Open Access Journals (Sweden)

Peter Puschner

2015-12-01

Full Text Available Abstract A Virtual Machine has led to a fully automatic spot welding system. All necessary parameters are created by measuring systems and algorithms running in the Virtual Machine. A hybrid operating circuit allows the Virtual Machine to read the exact process voltage between the tips of the electrodes every 50 µs. Actual welding voltage and current allow for the first time reading process impedance, electric power and total energy being transferred to the spot weld. Necessary energy input is calculated by a calorimetric model after measuring the total thickness of the materials to be welded as soon as the welding gun is positioned at the workpiece. A precision potentiometer implemented in the gun delivers the total material thickness within the 0.1 mm range during the pre-pressure phases. The internal databank of the Virtual Machine controls all essential parameters to guide the total welding process. Special generator characteristics of the welding power unit are created by the Virtual Machine just during the upslope and the welding phases. So the process will be initialized in differentiating the kind of material, mild steel or high strengthen steel. This will affect the kind of energy input and current decrease during the upslope and downslope phases.

Ultrasonic Real-Time Quality Monitoring Of Aluminum Spot Weld Process

Science.gov (United States)

Perez Regalado, Waldo Josue

The real-time ultrasonic spot weld monitoring system, introduced by our research group, has been designed for the unsupervised quality characterization of the spot welding process. It comprises the ultrasonic transducer (probe) built into one of the welding electrodes and an electronics hardware unit which gathers information from the transducer, performs real-time weld quality characterization and communicates with the robot programmable logic controller (PLC). The system has been fully developed for the inspection of spot welds manufactured in steel alloys, and has been mainly applied in the automotive industry. In recent years, a variety of materials have been introduced to the automotive industry. These include high strength steels, magnesium alloys, and aluminum alloys. Aluminum alloys have been of particular interest due to their high strength-to-weight ratio. Resistance spot welding requirements for aluminum vary greatly from those of steel. Additionally, the oxide film formed on the aluminum surface increases the heat generation between the copper electrodes and the aluminum plates leading to accelerated electrode deterioration. Preliminary studies showed that the real-time quality inspection system was not able to monitor spot welds manufactured with aluminum. The extensive experimental research, finite element modelling of the aluminum welding process and finite difference modeling of the acoustic wave propagation through the aluminum spot welds presented in this dissertation, revealed that the thermodynamics and hence the acoustic wave propagation through an aluminum and a steel spot weld differ significantly. For this reason, the hardware requirements and the algorithms developed to determine the welds quality from the ultrasonic data used on steel, no longer apply on aluminum spot welds. After updating the system and designing the required algorithms, parameters such as liquid nugget penetration and nugget diameter were available in the ultrasonic data

The Influence of Friction Stir Weld Tool Form and Welding Parameters on Weld Structure and Properties: Nugget Bulge in Self-Reacting Friction Stir Welds

Science.gov (United States)

Schneider, Judy; Nunes, Arthur C., Jr.; Brendel, Michael S.

2010-01-01

Although friction stir welding (FSW) was patented in 1991, process development has been based upon trial and error and the literature still exhibits little understanding of the mechanisms determining weld structure and properties. New concepts emerging from a better understanding of these mechanisms enhance the ability of FSW engineers to think about the FSW process in new ways, inevitably leading to advances in the technology. A kinematic approach in which the FSW flow process is decomposed into several simple flow components has been found to explain the basic structural features of FSW welds and to relate them to tool geometry and process parameters. Using this modelling approach, this study reports on a correlation between the features of the weld nugget, process parameters, weld tool geometry, and weld strength. This correlation presents a way to select process parameters for a given tool geometry so as to optimize weld strength. It also provides clues that may ultimately explain why the weld strength varies within the sample population.

Sediment Source Fingerprinting of the Lake Urmia Sand Dunes.

Science.gov (United States)

Ahmady-Birgani, Hesam; Agahi, Edris; Ahmadi, Seyed Javad; Erfanian, Mahdi

2018-01-09

Aeolian sand dunes are continuously being discovered in inner dry lands and coastal areas, most of which have been formed over the Last Glacial Maximum. Presently, due to some natural and anthropogenic implications on earth, newly-born sand dunes are quickly emerging. Lake Urmia, the world's second largest permanent hypersaline lake, has started shrinking, vast lands comprising sand dunes over the western shore of the lake have appeared and one question has been playing on the minds of nearby dwellers: where are these sand dunes coming from, What there was not 15 years ago!! In the present study, the determination of the source of the Lake Urmia sand dunes in terms of the quantifying relative contribution of each upstream geomorphological/lithological unit has been performed using geochemical fingerprinting techniques. The findings demonstrate that the alluvial and the fluvial sediments of the western upstream catchment have been transported by water erosion and they accumulated in the lower reaches of the Kahriz River. Wind erosion, as a secondary agent, have carried the aeolian sand-sized sediments to the sand dune area. Hence, the Lake Urmia sand dunes have been originating from simultaneous and joint actions of alluvial, fluvial and aeolian processes.

Automatic orbital GTAW welding: Highest quality welds for tomorrow's high-performance systems

Science.gov (United States)

Henon, B. K.

1985-01-01

Automatic orbital gas tungsten arc welding (GTAW) or TIG welding is certain to play an increasingly prominent role in tomorrow's technology. The welds are of the highest quality and the repeatability of automatic weldings is vastly superior to that of manual welding. Since less heat is applied to the weld during automatic welding than manual welding, there is less change in the metallurgical properties of the parent material. The possibility of accurate control and the cleanliness of the automatic GTAW welding process make it highly suitable to the welding of the more exotic and expensive materials which are now widely used in the aerospace and hydrospace industries. Titanium, stainless steel, Inconel, and Incoloy, as well as, aluminum can all be welded to the highest quality specifications automatically. Automatic orbital GTAW equipment is available for the fusion butt welding of tube-to-tube, as well as, tube to autobuttweld fittings. The same equipment can also be used for the fusion butt welding of up to 6 inch pipe with a wall thickness of up to 0.154 inches.

Influence of Welding Process and Post Weld Heat Treatment on Microstructure and Pitting Corrosion Behavior of Dissimilar Aluminium Alloy Welds

Science.gov (United States)

Venkata Ramana, V. S. N.; Mohammed, Raffi; Madhusudhan Reddy, G.; Srinivasa Rao, K.

2018-03-01

Welding of dissimilar Aluminum alloy welds is becoming important in aerospace, shipbuilding and defence applications. In the present work, an attempt has been made to weld dissimilar aluminium alloys using conventional gas tungsten arc welding (GTAW) and friction stir welding (FSW) processes. An attempt was also made to study the effect of post weld heat treatment (T4 condition) on microstructure and pitting corrosion behaviour of these welds. Results of the present investigation established the differences in microstructures of the base metals in T4 condition and in annealed conditions. It is evident that the thickness of the PMZ is relatively more on AA2014 side than that of AA6061 side. In FS welds, lamellar like shear bands are well noticed on the top of the stir zone. The concentration profile of dissimilar friction stir weld in T4 condition revealed that no diffusion has taken place at the interface. Poor Hardness is observed in all regions of FS welds compared to that of GTA welds. Pitting corrosion resistance of the dissimilar FS welds in all regions was improved by post weld heat treatment.

A control system for uniform bead in fillet arc welding on tack welds

International Nuclear Information System (INIS)

Kim, Jae Woong; Lee, Jun Young

2008-01-01

Positioning a workpiece accurately and preventing weld distortion, tack welding is often adopted before main welding in the construction of welded structures. However, this tack weld deteriorates the final weld bead profile, so that the grinding process is usually performed for a uniform weld bead profile. In this study, a control system for uniform weld bead is proposed for the fillet arc welding on tack welds. The system consists of GMA welding machine, torch manipulator, laser vision sensor for measuring the tack weld size and the database for optimal welding conditions. Experiments have been performed for constructing the database and for evaluating the control capability of the system. It has been shown that the system has the capability to smooth the bead at the high level of quality

Torque Measurement of Welding of Endplug-Endplate using Multi-pin Remote Welding System

Energy Technology Data Exchange (ETDEWEB)

Koo, Dae-Seo; Kim, Soo-Sung; Park, Geun-Il; Lee, Jung-Won; Song, Kee-Chan [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

2006-07-01

As fuel bundles in PHWR irradiates, inner pressure in claddings of fuel rods increases owing to outer pressure and fission products of nuclear fissions. Because of leak possibility of welding between cladding and end plug, this welding part connects with safety of nuclear fuel rods. Because of importance of this welding part, weldability of end plug-cladding of nuclear fuel rods is continually researched. Welding method for research and commercialization is classified as melting, solid type welding or resistance welding. End plug cladding welding of nuclear fuel rods in PHWR takes advantage of resistance upset butt welding using multicycle mode. This method makes weld flash and shapes re-entrant corner owing to welding heat due to resistivity, contact resistance of cladding-end plug, and inelasticity deformation due to pressure. Welding part between cladding and end plug receives stresses and makes small cracks. In this study, remote welding system for multi-pin assembly was designed, fabricated and welding specimens of end plug-endplate were made using electrical resistance method. The torques of welding between end plug and endplate were measured. These results on welding current, pressure of main electrode and pressure of branch electrode were analyzed. Weldability between end plug and endplate was confirmed through metallographic examinations. In the future, optimal welding examinations due to welding current, welding pressure and welding time will be performed to improve weldability of end plug-endplate.

Advantages of new micro-jet welding technology on weld microstructure control

Directory of Open Access Journals (Sweden)

Jan PIWNIK

2013-01-01

Full Text Available An innovative apparatus to welding process with micro-jet cooling of the weld made it possible to carry out technological tests, which have proved theoretical considerations about this problem. This project gives real opportunities for professional development in the field of welding with controlling the parameters of weld structure. These tests have proved that the new micro-jet technology has the potential for growth. It may be great achievement of welding technology in order to increase weld metal strength. The new technology with micro-jet cooling may have many practical applications in many fields, for example such as in the transport industry or to repair damaged metal elements. The advantages of the new device over the traditional system are the ability to control the structure of the weld, the weld mechanical performance increases and improve the quality of welded joints.

Weld repair issues in thick section austenitic pipework

International Nuclear Information System (INIS)

Goodwin, S.J.; Price, A.T.

1989-03-01

Thick section austenitic Type 316 Stainless steel, in the solution treated condition, has been used in Central Electricity Generating Board plant in the United Kingdom for some three decades and has given good service. Repair and replacement of this material after long term service is becoming a requirement and is complicated by the precipitation hardening and sensitisation of the materials. This paper summarises the compositional, microstructural and ageing characteristics of the wrought material and weld metals and the consequences for materials properties. Post weld heat treatment options are outlined and sensitisation to stress corrosion cracking is discussed. Finally, some examples of cracking that has occurred in plant after long term operation are given and weld repair research requirements are noted. (author)

Boat sampling and inservice inspections of the reactor pressure vessel weld No. 4 at Kozloduy NPP, Unit 1

International Nuclear Information System (INIS)

Cvitanovic, M.; Oreb, E.; Mudronja, V.; Zado, V.; Bezlaj, H.; Petkov, M.; Gledatchev, J.; Radomirski, S.; Ribarska, T.; Kroes, B.

1999-01-01

The paper deals with reactor pressure vessel (RPV) boat sampling performed at Kozloduy Nuclear Power Plant, Unit 1, from August to November 1996. Kozloduy NPP, Unit 1 has no reactor vessel material surveillance program. Changes in the material fracture toughness resulting from the fast neutron irradiation which cannot be monitored without removal of the vessel material. Therefore, the main objective of the project was to cut samples from the RPV wall in order to obtain samples of the RPV material for further structural analyses. The most critical area, i.e. weld No. 4 was determined as a location for boat sampling. Replication technique was applied in order to obtain precise determination of the weld geometry necessary for positioning of the cutting tool prior to boat sampling, and determination of divot depth left after boat sampling and grinding of sample sites. Boat sampling was performed by electrical discharge machining (EDM). Grinding of sample sites was implemented to minimize stress concentration effects on sample sites, to eliminate surface irregularities resulting from EDM process, and to eliminate recast layer on the surface of the EDM cut. Ultrasonic, liquid penetrant, magnetic particles, and visual examinations were performed after grinding to establish baseline data in the boat sampling area. The project preparation activities, apart from EDM process, and the site organization lead was entrusted to INETEC. The activities were funded by the PHARE program of the European Commission. (orig.)

TECHNOLOGICAL ISSUES IN MECHANISED FEED WIG/TIG WELDING SURFACING OF WELDING

Directory of Open Access Journals (Sweden)

BURCA Mircea

2016-09-01

manual welding tests in the light of using the process for welding surfacing being known that in such applications mechanised operations are recommended whenever possible given the latter strengths i.e. increased productivity and quality deposits. The research also aims at achieving a comparative a study between wire mechanised feed based WIG manual welding and the manual rod entry based manual welding in terms of geometry deposits, deposits aesthetics, operating technique, productivity, etc . In this regard deposits were made by means of two welding procedures, and subsequently welding surfacing was made with the optimum values of the welding parameters in this case.

Online quality monitoring of welding processes by means of plasma optical spectroscopy

Science.gov (United States)

Ferrara, Michele; Ancona, Antonio; Lugara, Pietro M.; Sibilano, Michele

2000-02-01

An optical monitoring system for the welding process has been developed; it is based on the study of the optical emission of the welding plasma plume, created during the welding of stainless steels and other iron-based materials. In the first approach a continuous wave CO2 laser of 2500-Watt maximum power, available at the INFM Research Unit labs in Bari University, has been used as welding source. A detailed spectroscopic study of the visible and UV welding plasma emission has been carried out; many transition lines corresponding to the elements composing the material to be welded have been found. By means of an appropriate selection of these lines and suitable algorithms, the electronic temperature of the plasma plume has been calculated and its evolution recorded as a function of several welding parameters. The behavior of the registered signal has resulted to be correlated to the welded joint quality. These findings have allowed to design and assemble a portable, non-intrusive and real-time welding quality optical sensor which has been successfully tested for laser welding of metals in different geometrical configurations; it has been capable of detecting a wide range of weld defects normally occurring during industrial laser metal-working. This sensor has also been tested in arc welding industrial processes (TIG) with promising results.

76 FR 76437 - Certain Welded Stainless Steel Pipe From Korea and Taiwan

Science.gov (United States)

2011-12-07

... Welded Stainless Steel Pipe From Korea and Taiwan Determination On the basis of the record \\1\\ developed... antidumping duty orders on certain welded stainless steel pipe from Korea and Taiwan would be likely to lead to continuation or recurrence of material injury to an industry in the United States within a...

High-Powered, Ultrasonically Assisted Thermal Stir Welding

Science.gov (United States)

Ding, Robert

2013-01-01

This method is a solid-state weld process capable of joining metallic alloys without melting. The weld workpieces to be joined by thermal stir welding (TSW) are drawn, by heavy forces, between containment plates past the TSW stir tool that then causes joining of the weld workpiece. TSW is similar to friction stir welding (FSW) in that material is heated into a plastic state (not melted) and stirred using a stir rod. The FSW pin tool is an integrated geometrical structure consisting of a large-diameter shoulder, and a smaller-diameter stir pin protruding from the shoulder. When the pin is plunged into a weld workpiece, the shoulder spins on the surface of the weld workpiece, thus inducing frictional heat into the part. The pin stirs the fraying surfaces of the weld joint, thus joining the weld workpiece into one structure. The shoulder and stir pin of the FSW pin tool must rotate together at a desired rotational speed. The induced frictional energy control and stir pin control of the pin tool cannot be de-coupled. The two work as one integrated unit. TSW, on the other hand, de-couples the heating and stirring of FSW, and allows for independent control of each process element. A uniquely designed induction coil heats the weld workpiece to a desired temperature, and once heated, the part moves into a stir rod whose RPM is also independently controlled. As the weld workpiece moves into the stir rod, the piece is positioned, or sandwiched, between upper and lower containment plates. The plate squeezes together, thus compressing the upper and lower surfaces of the weld workpiece. This compressive force, also called consolidation force, consolidates the plastic material within the weld nugget material as it is being stirred by the stir rod. The stir rod is positioned through the center of the top containment plate and protrudes midway through the opposite lower containment plate where it is mechanically captured. The upper and lower containment plates are separated by a

Welding Penetration Control of Fixed Pipe in TIG Welding Using Fuzzy Inference System

Science.gov (United States)

Baskoro, Ario Sunar; Kabutomori, Masashi; Suga, Yasuo

This paper presents a study on welding penetration control of fixed pipe in Tungsten Inert Gas (TIG) welding using fuzzy inference system. The welding penetration control is essential to the production quality welds with a specified geometry. For pipe welding using constant arc current and welding speed, the bead width becomes wider as the circumferential welding of small diameter pipes progresses. Having welded pipe in fixed position, obviously, the excessive arc current yields burn through of metals; in contrary, insufficient arc current produces imperfect welding. In order to avoid these errors and to obtain the uniform weld bead over the entire circumference of the pipe, the welding conditions should be controlled as the welding proceeds. This research studies the intelligent welding process of aluminum alloy pipe 6063S-T5 in fixed position using the AC welding machine. The monitoring system used a charge-coupled device (CCD) camera to monitor backside image of molten pool. The captured image was processed to recognize the edge of molten pool by image processing algorithm. Simulation of welding control using fuzzy inference system was constructed to simulate the welding control process. The simulation result shows that fuzzy controller was suitable for controlling the welding speed and appropriate to be implemented into the welding system. A series of experiments was conducted to evaluate the performance of the fuzzy controller. The experimental results show the effectiveness of the control system that is confirmed by sound welds.

Versatile Friction Stir Welding/Friction Plug Welding System

Science.gov (United States)

Carter, Robert

2006-01-01

A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

Environmental Impacts of Sand Exploitation. Analysis of Sand Market

Directory of Open Access Journals (Sweden)

Marius Dan Gavriletea

2017-06-01

Full Text Available Sand is an indispensable natural resource for any society. Despite society’s increasing dependence on sand, there are major challenges that this industry needs to deal with: limited sand resources, illegal mining, and environmental impact of sand mining. The purpose of this paper is twofold: to present an overview of the sand market, highlighting the main trends and actors for production, export and import, and to review the main environmental impacts associated with sand exploitation process. Based on these findings, we recommend different measures to be followed to reduce negative impacts. Sand mining should be done in a way that limits environmental damage during exploitation and restores the land after mining operations are completed.

Effect of Welding Parameters on Dilution and Weld Bead Geometry in Cladding

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The effect of pulsed gas metal arc welding (GMAW) variables on the dilution and weld bead geometry in cladding X65 pipeline steel with 316L stainless steel was studied. Using a full factorial method, a series of experiments were carried out to know the effect of wire feed rate, welding speed, distance between gas nozzle and plate, and the vertical angle of welding on dilution and weld bead geometry. The findings indicate that the dilution of weld metal and its dimension i.e. width, height and depth increase with the feed rate, but the contact angle of the bead decreases first and then increases. Meantime, welding speed has an opposite effect except for dilution. There is an interaction effect between welding parameters at the contact angle. The results also show forehand welding or decreasing electrode extension decrease the angle of contact. Finally,a mathematical model is contrived to highlight the relationship between welding variables with dilution and weld bead geometry.

Test work of sand compaction pile method on coal ash soil foundation. Sekitanbai jiban ni okeru sand compaction pile koho no shiken seko

Energy Technology Data Exchange (ETDEWEB)

Goto, K.; Maeda, S.; Shibata, T. (The Kansai Electric Power Co. Inc., Osaka (Japan))

1992-01-25

As an electric power supply source after the 1990 {prime}s, Nos. 5 and 6 units are additionally being constructed by Kansai Electric Power in its Himeji Power Station No.1 which is an exclusively LNG burning power station. The additional construction site of those units is of soil foundation reclaimed with coal ash which was used residual product in the existing No.1 through No.4 units. As a result of soil foundation survey, the coal ash layer and sand layer were known to be of material to be possibly liquidized at the time of earthquake. As measures against the liquidization, application was basically made of a sand compaction pile (SCP) method which is economical and abundant in record. However, that method was so short of record in the coal ash layer that its evaluation was difficult in soil reforming effect. Therefore, its applicability was evaluated by a work test on the site, which resulted in a confirmation that the coal ash as well as the sand can be sufficiently reformed by the SCP method. Started in September, 1991, the additional construction of Nos. 5 and 6 units in Himeji Power Station No.1 uses a 1.5m pitch SCP method to reform the soil foundation. 3 refs., 10 figs., 1 tab.

Study of Slow Sand Filtration in Removing Total Coliforms and E.Coli

Directory of Open Access Journals (Sweden)

Ekha Yogafanny

2015-08-01

Full Text Available This study was aimed to evaluate the performance of SSF in removing bacteria (Total Coliforms and E. Coli in regard to grain size distribution and grain shape intermittently. Two methodological approaches used in this reasearch were literature review and laboratory work. Bacteria removal was analyzed considering two different filter media (Rhine sand-spherical shape and Lava sand-angular shape with three different grain size distributions. The best performance was attained by filter column F4 which consisted of Lava sand and had the configuration C2 (d10 = 0.07 mm; Cu = 4.2. This filter column achieved 4.7log-units removal of Total Coliforms and 5.0log-units removal of E. coli. The results show that a smaller grain size and an angular shape of sand grain lead to an increase in bacteria removal.

The fracture mechanics of steam turbine electron beam welded rotors

International Nuclear Information System (INIS)

Coulon, P.A.

1987-01-01

Increased steam turbine unit ratings presupposes that steelmakers are capable of manufacturing larger and larger rotor components. However, there are few steelmakers in the world capable of manufacturing monobloc rotors for high rated turbines, which limits the choice of supplier. Most nuclear turbine rotors have a composite arrangement and are made either by shrinking discs on a shaft or using elements welded together. Those in favour of welding have applied a classical socalled ''submerged'' method using a filler metal. However welding can also be performed by using an Electron Beam in a vacuum room without a filler metal. This technique has many advantages: mechanical characteristics of the joint are identical to those of the base material after tempering without heat affected zones. Moreover, parts are only very slightly deformed during welding. Two steam turbine rotors have been produced in this way. This paper described the destructive tests carried out in the four Electron Beam (EB) welds (two on each rotor)

Modeling of welded bead profile for rapid prototyping by robotic MAG welding

Institute of Scientific and Technical Information of China (English)

CAO Yong; ZHU Sheng; WANG Tao; WANG Wanglong

2009-01-01

As a deposition technology, robotic metal active gas(MAG) welding has shown new promise for rapid prototyping (RP) of metallic parts. During the process of metal forming using robotic MAG welding, sectional profile of single-pass welded bead is critical to formed accuracy and quality of metal pans. In this paper, the experiments of single-pass welded bead for rapid prototyping using robotic MAG welding were carried out. The effect of some edge detectors on the cross-sectional edge of welded bead was discussed and curve fitting was applied using leat square fitting. Consequently, the mathematical model of welded bead profile was developed. The experimental results show that good shape could be obtained under suitable welding parameters. Canny operawr is suitable to edge detection of welded bead profile, and the mathematical model of welded bead profile developed is approximately parabola.

Sedimentology and composition of sands injected during the seismic crisis of May 2012 (Emilia, Italy): clues for source layer identification and liquefaction regime

Science.gov (United States)

Fontana, D.; Lugli, S.; Marchetti Dori, S.; Caputo, R.; Stefani, M.

2015-07-01

In May 2012 widespread sand blows formed along buried channels in the eastern sector of the Po Plain (Northern Italy) as a consequence of a series of seismic events with main shocks of Mw 6.1 and 5.9. At San Carlo (Ferrara) a trench dug a few week after the earthquakes exposed sand dikes cutting through an old Reno River channel-levee system that was diverted in the 18th century and was deposited starting from the 14th century (unit A). This sequence overlies a Holocene muddy floodplain deposits and contains scattered sandy channel deposits (unit B) and a Pleistocene channel sand unit (unit C). Sands with inverse and normal grading, concave layering and vertical lamination coexisting along the dikes suggest multiple rhythmic opening and closing of the fractures that were injected and filled by a slurry of sand during the compression pulses, and emptied during the extension phase. The pulse mechanism may have lasted for several minutes and formed well stratified sand volcanoes structures that formed at the top of the fractures. Sands from dikes and from the various units show well defined compositional fields from lithoarenitic to quartz-feldspar-rich compositions. Sands from the old Reno levee and channel fill (unit A) have abundant lithic fragments derived from the erosion of Apennine sedimentary carbonate and terrigenous successions. Composition of the sand filling the dikes show clear affinities with sand layers of the old Reno River channel (Unit A) and clearly differ from any sand from deeper Holocene and Pleistocene layers (Unit B and C), which are richer in quartz and feldspar and poorer in sedimentary lithic fragments. Sorting related to sediment flux variations did not apparently affect the sand composition across the sedimentary structures. Textural and compositional data indicate that the liquefaction processes originated from a relatively shallow source consisting of channel sands located within Unit A at 6.8.to 7.5 m depth.

Fusion welding process

Science.gov (United States)

Thomas, Kenneth C.; Jones, Eric D.; McBride, Marvin A.

1983-01-01

A process for the fusion welding of nickel alloy steel members wherein a ferrite containing pellet is inserted into a cavity in one member and melted by a welding torch. The resulting weld nugget, a fusion of the nickel containing alloy from the members to be welded and the pellet, has a composition which is sufficiently low in nickel content such that ferrite phases occur within the weld nugget, resulting in improved weld properties. The steel alloys encompassed also include alloys containing carbon and manganese, considered nickel equivalents.

Metal Cutting Theory and Friction Stir Welding Tool Design

Science.gov (United States)

Payton, Lewis N.

2003-01-01

Friction Stir Welding (FSW) is a relatively new industrial process that was invented at The Weld Institute (TWI, United Kingdom) and patented in 1992 under research funded by in part by the National Aeronautics and Space Administration (NASA). Often quoted advantages of the process include good strength and ductility along with minimization of residual stress and distortion. Less well advertised are the beneficial effects of this solid state welding process in the field of occupational and environmental safety. It produces superior weld products in difficult to weld materials without producing any toxic fumes or solid waste that must be controlled as hazardous waste. In fact, it reduces noise pollution in the workspace as well. In the early days of FSW, most welding was performed on modified machine tools, in particular on milling machines with modified milling cutters. In spite of the obvious milling heritage of the process, the techniques and lessons learned from almost 250 years of successful metalworking with milling machines have not been applied in the field of modern Friction Stir Welding. The goal of the current research was to study currently successful FSW tools and parameterize the process in such a way that the design of new tools for new materials could be accelerated. Along the way, several successful new tooling designs were developed for current issues at the Marshall Space Flight Center with accompanying patent disclosures

MAG narrow gap welding - an economic way to minimize welding expenses

International Nuclear Information System (INIS)

Kast, W.; Scholz, E.; Weyland, F.

1982-01-01

The thicker structural components are, the more important it is to take measures to reduce the volume of the weld. The welding process requiring the smallest possible weld section is the so-called narrow gap process. In submerged arc narrow gap welding as well as in MAG narrow gap welding different variants are imaginable, some of them already in practical use. With regard to efficiency and weld quality an optimum variant of the MAG narrow gap welding process is described. It constitutes a two wire system in which two wire electrodes of 1.2 mm diameter are arranged one behind the other. In order to avoid lack of fusion, the wire guides are slightly pointed towards each groove face. Thus, by inclining the two arcs burning one behind the other in the direction of weld progress, it is achieved that two separately solidifying weld pools and two beads per layer are simultaneously formed. Welding parameters are selected in such a way that a heat input of 16-20 kJ/cm and a deposition rate of 11-16 kgs/h are obtained. In spite of this comparatively high deposition rate, good impact values are found both in the weld and HAZ (largely reduced coarse-grain zone) which is due to an optimum weld build-up. With the available welding equipment the process can be applied to structural members having a thickness of 40-400 mm. The width of gap is 13 mm (root section) with a bevel angle of 1 0 . As filler metal, basic flux-cored wires are used which, depending on the base metal to be welded and the required tensile properties, can be of the Mn-, MnMo-, MnCrMo-, MnNi-, or MnNiMo-alloyed types. (orig.)

AWS and ASME welding problems in the nuclear industry

International Nuclear Information System (INIS)

Reedy, R.F.; Borter, W.H.

1984-01-01

The cost of nuclear power plant construction in the United States far exceeds the expectations of ten years ago, even considering high interest rates and inflation. The largest portion of the increased direct construction costs is related to delays and unnecessary repairs and rework. Most of these repairs and rework are related to welding. There is a way to start controlling these costs now, but it involves revising specifications and educating engineers regarding materials and welding

Advanced Welding Applications

Science.gov (United States)

Ding, Robert J.

2010-01-01

Some of the applications of advanced welding techniques are shown in this poster presentation. Included are brief explanations of the use on the Ares I and Ares V launch vehicle and on the Space Shuttle Launch vehicle. Also included are microstructural views from four advanced welding techniques: Variable Polarity Plasma Arc (VPPA) weld (fusion), self-reacting friction stir welding (SR-FSW), conventional FSW, and Tube Socket Weld (TSW) on aluminum.

WELDING METHOD

Science.gov (United States)

Cornell, A.A.; Dunbar, J.V.; Ruffner, J.H.

1959-09-29

A semi-automatic method is described for the weld joining of pipes and fittings which utilizes the inert gasshielded consumable electrode electric arc welding technique, comprising laying down the root pass at a first peripheral velocity and thereafter laying down the filler passes over the root pass necessary to complete the weld by revolving the pipes and fittings at a second peripheral velocity different from the first peripheral velocity, maintaining the welding head in a fixed position as to the specific direction of revolution, while the longitudinal axis of the welding head is disposed angularly in the direction of revolution at amounts between twenty minutas and about four degrees from the first position.

Friction stir welding tool and process for welding dissimilar materials

Science.gov (United States)

Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

2013-05-07

A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

Estimates of hydraulic fracturing (Frac) sand production, consumption, and reserves in the United States

Science.gov (United States)

Bleiwas, Donald I.

2015-01-01

The practice of fracturing reservoir rock in the United States as a method to increase the flow of oil and gas from wells has a relatively long history and can be traced back to 1858 in Fredonia, New York, when a gas well situated in shale of the Marcellus Formation was successfully fractured using black powder as a blasting agent. Nearly all domestic hydraulic fracturing, often referred to as hydrofracking or fracking, is a process where fluids are injected under high pressure through perforations in the horizontal portion of a well casing in order to generate fractures in reservoir rock with low permeability (“tight”). Because the fractures are in contact with the well bore they can serve as pathways for the recovery of gas and oil. To prevent the fractures generated by the fracking process from closing or becoming obstructed with debris, material termed “proppant,” most commonly high-silica sand, is injected along with water-rich fluids to maintain or “prop” open the fractures. The first commercial application of fracking in the oil and gas industry took place in Oklahoma and Texas during the 1940s. In 1949, over 300 wells, mostly vertical, were fracked (ALL Consulting, LLC, 2012; McGee, 2012; Veil, 2012) and used silica sand as a proppant (Fracline, 2011). The resulting increase in well productivity demonstrated the significant potential that fracking might have for the oil and gas industry.

Latest MIG, TIG arc-YAG laser hybrid welding systems for various welding products

Science.gov (United States)

Ishide, Takashi; Tsubota, Shuho; Watanabe, Masao

2003-03-01

Laser welding is capable of high-efficiency low-strain welding, and so its applications are started to various products. We have also put the high-power YAG laser of up to 10 kW to practical welding use for various products. On the other hand the weakest point of this laser welding is considered to be strict in the welding gap aiming allowance. In order to solve this problem, we have developed hybrid welding of TIG, MIG arc and YAG laser, taking the most advantages of both the laser and arc welding. Since the electrode is coaxial to the optical axis of the YAG laser in this process, it can be applied to welding of various objects. In the coaxial MIG, TIG-YAG welding, in order to make irradiation positions of the YAG laser beams having been guided in a wire or an electrode focused to the same position, the beam transmitted in fibers is separated to form a space between the separated beams, in which the laser is guided. With this method the beam-irradiating area can be brought near or to the arc-generating point. This enables welding of all directions even for the member of a three-dimensional shape. This time we carried out welding for various materials and have made their welding of up to 1 mm or more in welding groove gap possible. We have realized high-speed 1-pass butt welding of 4m/min in welding speed with the laser power of 3 kW for an aluminum alloy plate of approximately 4 mm thick. For a mild steel plate also we have realized butt welding of 1m/min with 5 kW for 6 mm thick. Further, in welding of stainless steel we have shown its welding possibility, by stabilizing the arc with the YAG laser in the welding atmosphere of pure argon, and shown that this welding is effective in high-efficiency welding of various materials. Here we will report the fundamental welding performances and applications to various objects for the coaxial MIG, TIG-YAG welding we have developed.

Ultrasonic testing of austenitic welds and its dependency on the welding process

International Nuclear Information System (INIS)

Tabatabaeipour, S.M.; Honarvar, F.

2009-01-01

This paper describes the ultrasonic testing of austenitic welds prepared by two different welding processes. The tests were carried out by the ultrasonic Time-of-Flight Diffraction (ToFD) technique. Shielded Metal Arc Welding (SMAW) and Gas Tungsten Arc Welding (GTAW) are the welding processes used for preparing the specimens. Identical artificial defects were implanted in both welds during the welding process. Both specimens were examined by the ToFD technique under similar conditions. Metallographic images were also obtained from the cross sectional plane of both the SMA and GTA welds. These images show that the grain orientation in the two welded specimens are different. D-scan images obtained by the ToFD technique from these welds indicates that inspecting the specimens prepared by the SMAW process is easier than the one made by the GTAW process. The results also show that the D-scan images cannot reveal the small vertical drilled holes implanted in the specimens. (author)

Friction Stir Welding of Tapered Thickness Welds Using an Adjustable Pin Tool

Science.gov (United States)

Adams, Glynn; Venable, Richard; Lawless, Kirby

2003-01-01

Friction stir welding (FSW) can be used for joining weld lands that vary in thickness along the length of the weld. An adjustable pin tool mechanism can be used to accomplish this in a single-pass, full-penetration weld by providing for precise changes in the pin length relative to the shoulder face during the weld process. The difficulty with this approach is in accurately adjusting the pin length to provide a consistent penetration ligament throughout the weld. The weld technique, control system, and instrumentation must account for mechanical and thermal compliances of the tooling system to conduct tapered welds successfully. In this study, a combination of static and in-situ measurements, as well as active control, is used to locate the pin accurately and maintain the desired penetration ligament. Frictional forces at the pin/shoulder interface were a source of error that affected accurate pin position. A traditional FSW pin tool design that requires a lead angle was used to join butt weld configurations that included both constant thickness and tapered sections. The pitch axis of the tooling was fixed throughout the weld; therefore, the effective lead angle in the tapered sections was restricted to within the tolerances allowed by the pin tool design. The sensitivity of the FSW process to factors such as thickness offset, joint gap, centerline offset, and taper transition offset were also studied. The joint gap and the thickness offset demonstrated the most adverse affects on the weld quality. Two separate tooling configurations were used to conduct tapered thickness welds successfully. The weld configurations included sections in which the thickness decreased along the weld, as well as sections in which the thickness increased along the weld. The data presented here include weld metallography, strength data, and process load data.

The technology and welding joint properties of hybrid laser-tig welding on thick plate

Science.gov (United States)

Shenghai, Zhang; Yifu, Shen; Huijuan, Qiu

2013-06-01

The technologies of autogenous laser welding and hybrid laser-TIG welding are used on thick plate of high strength lower alloy structural steel 10CrNiMnMoV in this article. The unique advantages of hybrid laser-TIG welding is summarized by comparing and analyzing the process parameters and welding joints of autogenous laser welding laser welding and hybrid laser-TIG welding. With the optimal process parameters of hybrid welding, the good welding joint without visible flaws can be obtained and its mechanical properties are tested according to industry standards. The results show that the hybrid welding technology has certain advantages and possibility in welding thick plates. It can reduce the demands of laser power, and it is significant for lowering the aspect ratio of weld during hybrid welding, so the gas in the molten pool can rise and escape easily while welding thick plates. Therefore, the pores forming tendency decreases. At the same time, hybrid welding enhances welding speed, and optimizes the energy input. The transition and grain size of the microstructure of hybrid welding joint is better and its hardness is higher than base material. Furthermore, its tensile strength and impact toughness is as good as base material. Consequently, the hybrid welding joint can meet the industry needs completely.

Effects of post weld heat treatment and weld overlay on the residual stress and mechanical properties in dissimilar metal weld

International Nuclear Information System (INIS)

Campos, Wagner R.C.; Ribeiro, Vladimir S.; Vilela, Alisson H.F.; Almeida, Camila R.O.; Rabello, Emerson G.

2017-01-01

The object of this work is a dissimilar metal weld (DMW) pipe joint between carbon steel (A-106 Gr B) and stainless steel (A-312 TP316L) pipes and filler metals of Nickel alloy (82/182), which find wide application in the field of chemical, oil, petroleum industries, fossil fuel and nuclear power plant. A lot of the failures that have occurred in dissimilar metal welded are affected greatly by residual stresses. Residual stress is often a cause of premature failure of critical components under normal operation of welded components. Several methods have been tested and developed for removing the tensile residual stresses. The aim of the methods is to reduce the tensile stress state or to create compressive stresses at a predefined area, such as the inner surface of a welded pipe joint. Post weld heat treatment (PWHT) and weld overlay (WOL) are two of the residual stress mitigation methods which reduce the tensile residual stress, create compressive stresses and arrest crack initiation and crack growth. The technique used to substantially minimized or eliminated this failure development in the root weld is the post weld heat treatments (stress relief heat treatment) or the weld overlay. In this work was studied the effectiveness in reducing internal residual stress in dissimilar metal welded pipe joints subjected to post weld heat treatment and weld overlay, measurement by hole-drilling strain-gage method of stress relaxation. Also held was mechanical characterization of the welded pipe joint itself. (author)

Effects of post weld heat treatment and weld overlay on the residual stress and mechanical properties in dissimilar metal weld

Energy Technology Data Exchange (ETDEWEB)

Campos, Wagner R.C.; Ribeiro, Vladimir S.; Vilela, Alisson H.F.; Almeida, Camila R.O.; Rabello, Emerson G., E-mail: wrcc@cdtn.br, E-mail: camilarezende.cr@gmail.com, E-mail: egr@cdtn.br, E-mail: vladimirsoler@hotmail.com, E-mail: ahfv02@outlook.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

The object of this work is a dissimilar metal weld (DMW) pipe joint between carbon steel (A-106 Gr B) and stainless steel (A-312 TP316L) pipes and filler metals of Nickel alloy (82/182), which find wide application in the field of chemical, oil, petroleum industries, fossil fuel and nuclear power plant. A lot of the failures that have occurred in dissimilar metal welded are affected greatly by residual stresses. Residual stress is often a cause of premature failure of critical components under normal operation of welded components. Several methods have been tested and developed for removing the tensile residual stresses. The aim of the methods is to reduce the tensile stress state or to create compressive stresses at a predefined area, such as the inner surface of a welded pipe joint. Post weld heat treatment (PWHT) and weld overlay (WOL) are two of the residual stress mitigation methods which reduce the tensile residual stress, create compressive stresses and arrest crack initiation and crack growth. The technique used to substantially minimized or eliminated this failure development in the root weld is the post weld heat treatments (stress relief heat treatment) or the weld overlay. In this work was studied the effectiveness in reducing internal residual stress in dissimilar metal welded pipe joints subjected to post weld heat treatment and weld overlay, measurement by hole-drilling strain-gage method of stress relaxation. Also held was mechanical characterization of the welded pipe joint itself. (author)

On use of weld zone temperatures for online monitoring of weld quality in friction stir welding of naturally aged aluminium alloys

International Nuclear Information System (INIS)

Imam, Murshid; Biswas, Kajal; Racherla, Vikranth

2013-01-01

Highlights: • FSWs for 6063-T4 AA are done at different process parameters and sheet thicknesses. • Weld nugget zone and heat affected zone temperatures are monitored for each case. • Microstructural and mechanical characterisation of welds is done in all cases. • Weld ductility is found to be particularly sensitive to weld zone temperatures. • Strong correlation is found between WNZ and HAZ temperatures and weld properties. - Abstract: 6063-T4 aluminium alloy sheets of 3 and 6 mm thicknesses were friction stir butt welded using a square tool pin at a wide range of tool rotational speeds. Properties of obtained welds were characterised using tensile tests, optical micrographs, X-ray diffraction, and transmission electron microscopy. Shape, size, and distribution of precipitates in weld zones, and strength and ductility of welds were seen to directly correlate with peak temperatures in weld nugget and heat affected zones, independent of sheet thickness. In addition, fluctuations in measured temperature profiles, for 3 mm sheets, were seen to correlate with an increase in scatter of weld nugget zone properties for 3 mm sheets. Optimal weld strength and ductility were obtained for peak weld nugget zone temperatures of around 450 °C and corresponding peak heat affected zone temperatures of around 360–380 °C. Results obtained suggest that, at least for naturally aged aluminium alloys, nature of temperature evolution and magnitudes of peak temperatures in weld nugget and heat affected zones provide information on uniformity of properties in weld zones, overaging of heat affected zones, and formation of tunnel defects from improper material mixing at low weld zone temperatures

Microcontroller based automation system for end plug welding of test fuel pins in solgel facility

International Nuclear Information System (INIS)

Prabhakar Rao, J.; Srinivas, K.C.; Prabhu, T.V.; Ravi, N.

2010-01-01

A microcontroller based stepper motor control and driver Unit for 'XY' positioning system is designed and developed to perform the 'pick-place' of fuel tube to pre-determined coordinates. This Unit provides a fine movement of the fuel tube to get perfect position for welding. The Graphical User Interface software running on PC displays the absolute position of the XY system and provides all the required control buttons to achieve the accurate positioning. The welding of clad tube with end plug is carried out in a high precision welding fixture by operating it remotely. This paper discusses about the Hardware and Software features and implementation of the instrumentation. (author)

Electromagnetic characteristic of twin-wire indirect arc welding

Science.gov (United States)

Shi, Chuanwei; Zou, Yong; Zou, Zengda; Wu, Dongting

2015-01-01

Traditional welding methods are limited in low heat input to workpiece and high welding wire melting rate. Twin-wire indirect arc(TWIA) welding is a new welding method characterized by high melting rate and low heat input. This method uses two wires: one connected to the negative electrode and another to the positive electrode of a direct-current(DC) power source. The workpiece is an independent, non-connected unit. A three dimensional finite element model of TWIA is devised. Electric and magnetic fields are calculated and their influence upon TWIA behavior and the welding process is discussed. The results show that with a 100 A welding current, the maximum temperature reached is 17 758 K, arc voltage is 14.646 V while maximum current density was 61 A/mm2 with a maximum Lorene force of 84.5 μN. The above mentioned arc parameters near the cathode and anode regions are far higher than those in the arc column region. The Lorene force is the key reason for plasma velocity direction deviated and charged particles flowed in the channel formed by the cathode, anode and upper part of arc column regions. This led to most of the energy being supplied to the polar and upper part of arc column regions. The interaction between electric and magnetic fields is a major determinant in shaping TWIA as well as heat input on the workpiece. This is a first study of electromagnetic characteristics and their influences in the TWIA welding process, and it is significant in both a theoretical and practical sense.

Measuring weld heat to evaluate weld integrity

Energy Technology Data Exchange (ETDEWEB)

Schauder, V., E-mail: schauder@hks-prozesstechnik.de [HKS-Prozesstechnik GmbH, Halle (Germany)

2015-11-15

Eddy current and ultrasonic testing are suitable for tube and pipe mills and have been used for weld seam flaw detection for decades, but a new process, thermography, is an alternative. By measuring the heat signature of the weld seam as it cools, it provides information about weld integrity at and below the surface. The thermal processes used to join metals, such as plasma, induction, laser, and gas tungsten arc welding (GTAW), have improved since they were developed, and they get better with each passing year. However, no industrial process is perfect, so companies that conduct research in flaw detection likewise continue to develop and improve the technologies used to verify weld integrity: ultrasonic testing (UT), eddy current testing (ET), hydrostatic, X-ray, magnetic particle, and liquid penetrant are among the most common. Two of these are used for verifying the integrity of the continuous welds such as those used on pipe and tube mills: UT and ET. Each uses a transmitter to send waves of ultrasonic energy or electrical current through the material and a receiver (probe) to detect disturbances in the flow. The two processes often are combined to capitalize on the strengths of each. While ET is good at detecting flaws at or near the surface, UT penetrates the material, detecting subsurface flaws. One drawback is that sound waves and electrical current waves have a specific direction of travel, or an alignment. A linear defect that runs parallel to the direction of travel of the ultrasonic sound wave or a flaw that is parallel to the coil winding direction of the ET probe can go undetected. A second drawback is that they don't detect cold welds. An alternative process, thermography, works in a different fashion: It monitors the heat of the material as the weld cools. Although it measures the heat at the surface, the heat signature provides clues about cooling activity deep in the material, resulting in a thorough assessment of the weld's integrity It

Maintenance service for major component of PWR plant. Replacement of pressurizer safe end weld

International Nuclear Information System (INIS)

Miyoshi, Yoshiyuki; Kobayashi, Yuki; Yamamoto, Kazuhide; Ueda, Takeshi; Suda, Naoki; Shintani, Takashi

2017-01-01

In October 2016, MHI completed the replacement of safe end weld of pressurizer (Pz) of Ringhals unit 3, which was the first maintenance work for main component of pressurized water reactor (PWR) plant in Europe. For higher reliability and longer lifetime of PWR plant, MHI has conducted many kinds of maintenance works of main components of PWR plants in Japan against stress corrosion cracking due to aging degradation. Technical process for replacement of Pz safe end weld were established by MHI. MHI has experienced the work for 21 PWR units in Japan. That of Ringhals unit 3 was planned and conducted based on the experiences. In this work, Alloy 600 used for welds of nozzles of Pz was replaced with Alloy 690. Alloy 690 is more corrosive-resistant than Alloy 600. Specially designed equipment and technical process were developed and established by MHI to replace safe end weld of Pz and applied for the Ringhals unit 3 as a first application in Europe. The application had been performed in success and achieved the planned replacement work duration and total radiation dose by using sophisticated machining and welding equipment designed to meet the requirements to be small, lightweight and remote-controlled and operating by well skilled MHI personnel experienced in maintenance activities for major components of PWR plant in Japan. The success shows that the experience, activities and technology developed in Japan for main components of PWR plant shall be applicable to contribute reliable operations of nuclear power plants in Europe and other countries. (author)

The effect of post-welding conditions in friction stir welds: From weld simulation to Ductile Failure

DEFF Research Database (Denmark)

Hattel, Jesper Henri; Nielsen, Kim Lau; Tutum, Cem Celal

2012-01-01

software ANSYS, a thermo-mechanical model is employed to predict the thermally induced stresses and strains during welding, while an in-house finite element code is used to study the plastic flow localization and failure in a subsequent structural analysis. The coupling between the two models is made......The post-welding stress state, strain history and material conditions of friction stir welded joints are often strongly idealized when used in subsequent modeling analyses, typically by neglecting one or more of the features above. But, it is obvious that the conditions after welding do influence......, showed the largest influence of the post-welding conditions, even though significant relaxation of the residual stress state was predicted....

Nitrogen And Oxygen Amount In Weld After Welding With Micro-Jet Cooling

Directory of Open Access Journals (Sweden)

Węgrzyn T.

2015-06-01

Full Text Available Micro-jet cooling after welding was tested only for MIG welding process with argon, helium and nitrogen as a shielded gases. A paper presents a piece of information about nitrogen and oxygen in weld after micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given main information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was presented in terms of nitrogen and oxygen amount in WMD (weld metal deposit.

A study of weld quality in ultrasonic spot welding of similar and dissimilar metals

International Nuclear Information System (INIS)

Al-Sarraf, Z; Lucas, M

2012-01-01

Several difficulties are faced in joining thinner sheets of similar and dissimilar materials from fusion welding processes such as resistance welding and laser welding. Ultrasonic metal welding overcomes many of these difficulties by using high frequency vibration and applied pressure to create a solid-state weld. Ultrasonic metal welding is an effective technique in joining small components, such as in wire bonding, but is also capable of joining thicker sheet, depending on the control of welding conditions. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal welding device. The ultrasonic welding horn is modelled using finite element analysis and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. Control of the vibration amplitude profile through the weld cycle is used to enhance weld strength and quality, providing an opportunity to reduce part marking. Optical microscopic examination and scanning electron microscopy (SEM) were employed to investigate the weld quality. The results show how the weld quality is particularly sensitive to the combination of clamping force and vibration amplitude of the welding tip.

Welding and cutting

International Nuclear Information System (INIS)

Drews, P.; Schulze Frielinghaus, W.

1978-01-01

This is a survey, with 198 literature references, of the papers published in the fields of welding and cutting within the last three years. The subjects dealt with are: weldability of the materials - Welding methods - Thermal cutting - Shaping and calculation of welded joints - Environmental protection in welding and cutting. (orig.) [de

Simplified welding distortion analysis for fillet welding using composite shell elements

Directory of Open Access Journals (Sweden)

Mingyu Kim

2015-05-01

Full Text Available This paper presents the simplified welding distortion analysis method to predict the welding deformation of both plate and stiffener in fillet welds. Currently, the methods based on equivalent thermal strain like Strain as Direct Boundary (SDB has been widely used due to effective prediction of welding deformation. Regarding the fillet welding, however, those methods cannot represent deformation of both members at once since the temperature degree of freedom is shared at the intersection nodes in both members. In this paper, we propose new approach to simulate deformation of both members. The method can simulate fillet weld deformations by employing composite shell element and using different thermal expansion coefficients according to thickness direction with fixed temperature at intersection nodes. For verification purpose, we compare of result from experiments, 3D thermo elastic plastic analysis, SDB method and proposed method. Compared of experiments results, the proposed method can effectively predict welding deformation for fillet welds.

Welding Technician

Science.gov (United States)

Smith, Ken

2009-01-01

About 95% of all manufactured goods in this country are welded or joined in some way. These welded products range in nature from bicycle handlebars and skyscrapers to bridges and race cars. The author discusses what students need to know about careers for welding technicians--wages, responsibilities, skills needed, career advancement…

Orbital welding technique

International Nuclear Information System (INIS)

Hoeschen, W.

2003-01-01

The TIG (Tungsten-inert gas) orbital welding technique is applied in all areas of pipe welding. The process is mainly used for austenitic and ferritic materials but also for materials like aluminium, nickel, and titanium alloys are commonly welded according to this technique. Thin-walled as well as thick-walled pipes are welded economically. The application of orbital welding is of particular interest in the area of maintenance of thick-walled pipes that is described in this article. (orig.) [de

Welding stresses

International Nuclear Information System (INIS)

Poirier, J.; Barbe, B.; Jolly, N.

1976-01-01

The aim is to show how internal stresses are generated and to fix the orders of magnitude. A realistic case, the vertical welding of thick plates free to move one against the other, is described and the deformations and stresses are analyzed. The mathematical model UEDA, which accounts for the elastic modulus, the yield strength and the expansion coefficient of the metal with temperature, is presented. The hypotheses and results given apply only to the instantaneous welding of a welded plate and to a plate welded by a moving electrode [fr

Reduction of Biomechanical and Welding Fume Exposures in Stud Welding.

Science.gov (United States)

Fethke, Nathan B; Peters, Thomas M; Leonard, Stephanie; Metwali, Mahmoud; Mudunkotuwa, Imali A

2016-04-01

The welding of shear stud connectors to structural steel in construction requires a prolonged stooped posture that exposes ironworkers to biomechanical and welding fume hazards. In this study, biomechanical and welding fume exposures during stud welding using conventional methods were compared to exposures associated with use of a prototype system that allowed participants to weld from an upright position. The effect of base material (i.e. bare structural beam versus galvanized decking) on welding fume concentration (particle number and mass), particle size distribution, and particle composition was also explored. Thirty participants completed a series of stud welding simulations in a local apprenticeship training facility. Use of the upright system was associated with substantial reductions in trunk inclination and the activity levels of several muscle groups. Inhalable mass concentrations of welding fume (averaged over ~18 min) when using conventional methods were high (18.2 mg m(-3) for bare beam; 65.7 mg m(-3) for through deck), with estimated mass concentrations of iron (7.8 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), zinc (0.2 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), and manganese (0.9 mg m(-3) for bare beam; 1.5 mg m(-3) for through deck) often exceeding the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLVs). Number and mass concentrations were substantially reduced when using the upright system, although the total inhalable mass concentration remained above the TLV when welding through decking. The average diameters of the welding fume particles for both bare beam (31±17 nm) through deck conditions (34±34 nm) and the chemical composition of the particles indicated the presence of metallic nanoparticles. Stud welding exposes ironworkers to potentially high levels of biomechanical loading (primarily to the low back) and welding fume. The upright system used in this study improved exposure

High-Speed Friction-Stir Welding to Enable Aluminum Tailor-Welded Blanks

Science.gov (United States)

Hovanski, Yuri; Upadhyay, Piyush; Carsley, John; Luzanski, Tom; Carlson, Blair; Eisenmenger, Mark; Soulami, Ayoub; Marshall, Dustin; Landino, Brandon; Hartfield-Wunsch, Susan

2015-05-01

Current welding technologies for production of aluminum tailor-welded blanks (TWBs) are utilized in low-volume and niche applications, and they have yet to be scaled for the high-volume vehicle market. This study targeted further weight reduction, part reduction, and cost savings by enabling tailor-welded blank technology for aluminum alloys at high volumes. While friction-stir welding (FSW) has been traditionally applied at linear velocities less than 1 m/min, high-volume production applications demand the process be extended to higher velocities more amenable to cost-sensitive production environments. Unfortunately, weld parameters and performance developed and characterized at low-to-moderate welding velocities do not directly translate to high-speed linear FSW. Therefore, to facilitate production of high-volume aluminum FSW components, parameters were developed with a minimum welding velocity of 3 m/min. With an emphasis on weld quality, welded blanks were evaluated for postweld formability using a combination of numerical and experimental methods. An evaluation across scales was ultimately validated by stamping full-size production door inner panels made from dissimilar thickness aluminum TWBs, which provided validation of the numerical and experimental analysis of laboratory-scale tests.

Estimation of weld nugget temperature by thermography method in resistance projection welding process

International Nuclear Information System (INIS)

Setty, D.S.; Rameswara Roa, A.; Hemantha Rao, G.V.S.; Jaya Raj, R.N.

2008-01-01

In the Pressurized Heavy Water Reactor (PHWR) fuel manufacturing, zirconium alloy appendages like spacer and bearing pads are welded to the thin wall zirconium alloy fuel tubes by using resistance projection welding process. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. In the fuel assembly, spacer pads are used to get the required inter-element spacing and Bearing pads are used to get the required load-bearing surface for the fuel assembly. Performance of the fuel assembly in the reactor is greatly influenced by these weld joint's quality. Phase transformation from α to β phase is not acceptable while welding these tiny appendages. At present only destructive metallography test is available for this purpose. This can also be achieved by measuring weld nugget temperature where in the phase transformation temperature for zirconium alloy material is 853 o C. The temperature distribution during resistance welding of tiny parts cannot be measured by conventional methods due to very small space and short weld times involved in the process. Shear strength, dimensional accuracy and weld microstructures are some of the key parameters used to measure the quality of appendage weld joints. Weld parameters were optimized with the help of industrial experimentation methodology. Individual projection welding by split electrode concept, and during welding on empty tube firm support is achieved on inner side of the tube by using expandable pneumatic mandrel. In the present paper, an attempt was made to measure the weld nugget temperature by thermography technique and is correlated with standard microstructures of zirconium alloy material. The temperature profiles in the welding process are presented for different welding conditions. This technique has helped in measuring the weld nugget temperature more accurately. It was observed that in the present appendage welding

Influence of Loading Direction and Weld Reinforcement on Fatigue Performance of TIG Weld Seam

Directory of Open Access Journals (Sweden)

HUI Li

2018-02-01

Full Text Available The influence of loading direction and weld reinforcement on fatigue performance of TC2 titanium alloy TIG weld seam was investigated via fatigue experiments and SEM fracture observation. The results show that the fatigue life of retaining weld reinforcement specimens is lower than that of removing one in the same weld direction. The fatigue life of oblique weld specimens is higher than that of straight one with the same weld reinforcement treatment. The initiation of removing weld reinforcement specimens' fatigue crack sources is in the hole defect, but the weld reinforcement specimen initiate at the weld toes. During the early stage of fatigue crack propagation, the cracks all grow inside the weld seam metal with obvious fatigue striation. And the fatigue cracks of oblique weld specimens pass through the weld seam into the base with a typical toughness fatigue striation during the last stage of fatigue crack propagation. The dimple of straight weld specimens is little and shallow in the final fracture zone. The oblique weld specimens broke in the base metal area, and the dimple is dense.

The energy efficiency of oil sands extraction: Energy return ratios from 1970 to 2010

International Nuclear Information System (INIS)

Brandt, Adam R.; Englander, Jacob; Bharadwaj, Sharad

2013-01-01

It has been argued that the oil sands industry is not energy efficient: comparatively large energy inputs are required per unit of energy output from oil sands operations. Unfortunately, quantitative work to date in this area has suffered from poor data availability and uncertain methods. We apply a new methodology and new dataset to compute ERRs (energy return ratios) for the oil sands industry. We collected monthly oil sands energy consumption and output data from 1970 to 2010. Current oil sands operations have mine mouth NERs (net energy returns) of about 6 GJ output per GJ of energy consumed and point of use energy returns of about 3 GJ/GJ. Long-term trends show oil sands operations becoming significantly more efficient: point of use NER increased from about 1 GJ/GJ in 1970 to 3 GJ/GJ in 2010. These energy returns are lower than those observed in historical conventional oil operations, but low energy returns are not likely to hinder development of oil sands operations due to the large resource in place and the ability for largely self-fueled pathways to return significant amounts of energy to society for every unit of external energy supplied. - Highlights: • Oil sands operations have become significantly more energy efficient over the history of the industry. • Oil sands production is largely fueled with energy from the bitumen resource itself, making external energy returns high. • Oil sands production is still significantly less efficient than conventional oil production

Nitrogen And Oxygen Amount In Weld After Welding With Micro-Jet Cooling

OpenAIRE

Węgrzyn T.; Piwnik J.

2015-01-01

Micro-jet cooling after welding was tested only for MIG welding process with argon, helium and nitrogen as a shielded gases. A paper presents a piece of information about nitrogen and oxygen in weld after micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given main information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was pr...

Hardness prediction for the repair welding of 2.25Cr-1Mo pressure vessels

International Nuclear Information System (INIS)

Oddy, A.S.; Chandel, R.S.

1991-01-01

Reactor vessels used for the hydrotreating of heavy oils and tar sand bitumen are frequently made of 2.25Cr-1Mo steel in thicknesses of 150 to 300 nm. Defects developed during installation or service are often repaired by welding. For practical reasons, postweld heat treatment of the repair welds is undesirable. This has led to continued effort to develop weld repair techniques that do not involve postweld heat treatment. Recently a six-layer automatic gas tungsten arc welding (GTAW) technique has been proposed for the repair welding of nuclear reactor vessels made of SA508 Class 2 Steel. In this technique, the second and third passes refine the microstructure of the first pass, and the last three passes temper the first pass. Alberry has developed a set of empirical rules predicting the hardness after each pass in multipass welds made in SA508 Class 2 Steels. This algorithm has been used to predict the number of layers required to achieve desired hardness. A transformation and tempering algorithm for 2.25Cr-1Mo, similar to that of the above steel, is presented. The tempering algorithm of Alberry suffers from several minor problems and can be improved. A mathematically correct method for the calculation of the tempering occurring in an anisothermal cycle is demonstrated. In addition, the rules used to relate the softening that occurs during temperature are heuristic. Separate rules are proposed for the kinetics of softening depending on the peak temperature. A re-examination of those rules reveals that they can be recast in the form of a single rule for the material examined. Reassessing the basic data presented by Alberry leads to a single softening rule with better theoretical justification

Influence of weld structure on cross-weld creep behavior in P23 steel

Energy Technology Data Exchange (ETDEWEB)

Allen, D.J.; Degnan, C.C. [E.ON Engineering (United Kingdom); Brett, S.J. [RWE npower (United Kingdom); Buchanan, L.W. [Doosan Babcock (United Kingdom)

2010-07-01

A thick section pipe weld in low alloy steel P23 has been characterised by cross-weld creep rupture testing at a range of stresses, together with all-weld-metal and parent material testing, under the auspices of the UK High Temperature Power Plant Forum. The results generally show that the weld metal can be weak when tested in the transverse (cross-weld) orientation, and can fail with limited overall ductility by cracking in the zone of refined weld metal beneath the fusion boundary of the superposed weld bead. However, one specimen showed a much superior performance, which could be understood in terms of its locally more creep resistant weld macrostructure. The implications for P23 performance and weld manufacture are discussed. (orig.)

Welded joints integrity analysis and optimization for fiber laser welding of dissimilar materials

Science.gov (United States)

Ai, Yuewei; Shao, Xinyu; Jiang, Ping; Li, Peigen; Liu, Yang; Liu, Wei

2016-11-01

Dissimilar materials welded joints provide many advantages in power, automotive, chemical, and spacecraft industries. The weld bead integrity which is determined by process parameters plays a significant role in the welding quality during the fiber laser welding (FLW) of dissimilar materials. In this paper, an optimization method by taking the integrity of the weld bead and weld area into consideration is proposed for FLW of dissimilar materials, the low carbon steel and stainless steel. The relationships between the weld bead integrity and process parameters are developed by the genetic algorithm optimized back propagation neural network (GA-BPNN). The particle swarm optimization (PSO) algorithm is taken for optimizing the predicted outputs from GA-BPNN for the objective. Through the optimization process, the desired weld bead with good integrity and minimum weld area are obtained and the corresponding microstructure and microhardness are excellent. The mechanical properties of the optimized joints are greatly improved compared with that of the un-optimized welded joints. Moreover, the effects of significant factors are analyzed based on the statistical approach and the laser power (LP) is identified as the most significant factor on the weld bead integrity and weld area. The results indicate that the proposed method is effective for improving the reliability and stability of welded joints in the practical production.

75 FR 76025 - Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan

Science.gov (United States)

2010-12-07

... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 731-TA-376 and 563-564 (Third Review)] Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan AGENCY: United States International... steel butt-weld pipe fittings from Japan, Korea, and Taiwan would be likely to lead to continuation or...

Laser Welding Test Results with Gas Atmospheres in Welding Chamber

Energy Technology Data Exchange (ETDEWEB)

Joung, Chang-Young; Hong, Jin-Tae; Ahn, Sung-Ho; Heo, Sung-Ho; Jang, Seo-Yun; Yang, Tae-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

The weld beads of specimens welded under identical conditions in the helium and argon gas were cleaner, more regular, and steadier than those in a vacuum. The penetration depth of the FZ in the vacuum was much deeper than those in the helium and argon gas. To measure the irradiation properties of nuclear fuel in a test reactor, a nuclear fuel test rod instrumented with various sensors must be fabricated with assembly processes. A laser welding system to assemble the nuclear fuel test rod was designed and fabricated to develop various welding technologies of the fuel test rods to joint between a cladding tube and end-caps. It is an air-cooling optical fiber type and its emission modes are a continuous (CW) mode of which the laser generates continuous emission, and pulse (QCW) mode in which the laser internally generates sequences of pulses. We considered the system welding a sample in a chamber that can weld a specimen in a vacuum and inert gas atmosphere, and the chamber was installed on the working plate of the laser welding system. In the chamber, the laser welding process should be conducted to have no defects on the sealing area between a cladding tube and an end-cap.

Welding of Thin Steel Plates by Hybrid Welding Process Combined TIG Arc with YAG Laser

Science.gov (United States)

Kim, Taewon; Suga, Yasuo; Koike, Takashi

TIG arc welding and laser welding are used widely in the world. However, these welding processes have some advantages and problems respectively. In order to improve problems and make use of advantages of the arc welding and the laser welding processes, hybrid welding process combined the TIG arc with the YAG laser was studied. Especially, the suitable welding conditions for thin steel plate welding were investigated to obtain sound weld with beautiful surface and back beads but without weld defects. As a result, it was confirmed that the shot position of the laser beam is very important to obtain sound welds in hybrid welding. Therefore, a new intelligent system to monitor the welding area using vision sensor is constructed. Furthermore, control system to shot the laser beam to a selected position in molten pool, which is formed by TIG arc, is constructed. As a result of welding experiments using these systems, it is confirmed that the hybrid welding process and the control system are effective on the stable welding of thin stainless steel plates.

Hybrid laser-arc welding

DEFF Research Database (Denmark)

Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

[New welding processes and health effects of welding].

Science.gov (United States)

La Vecchia, G Marina; Maestrelli, Piero

2011-01-01

This paper describes some of the recent developments in the control technology to enhance capability of Pulse Gas Metal Arc Welding. Friction Stir Welding (FSW) processing has been also considered. FSW is a new solid-state joining technique. Heat generated by friction at the rotating tool softens the material being welded. FSW can be considered a green and energy-efficient technique without deleterious fumes, gas, radiation, and noise. Application of new welding processes is limited and studies on health effects in exposed workers are lacking. Acute and chronic health effects of conventional welding have been described. Metal fume fever and cross-shift decline of lung function are the main acute respiratory effects. Skin and eyes may be affected by heat, electricity and UV radiations. Chronic effects on respiratory system include chronic bronchitis, a benign pneumoconiosis (siderosis), asthma, and a possible increase in the incidence of lung cancer. Pulmonary infections are increased in terms of severity, duration, and frequency among welders.

Plug-welding of ODS cladding tube for BOR-60 irradiation. Welding condition setting. Device remodeling and welding

International Nuclear Information System (INIS)

Seki, Masayuki; Ishibashi, Fujio; Kono, Syusaku; Hirako, Kazuhito; Tsukada, Tatsuya

2003-04-01

Irradiation test in BOR-60 at RIAR to judge practical use prospect of ODS cladding tube at early stage is planned as Japan-Russia a joint research. RIAR does fuel design of fuel pin used for this joint research. JNC manufactures ODS cladding tube and bar materials (two steel kind of martensite and ferrite), upper endplug production. They are welded by pressurized resistance welding, and are inspected in JNC Tokai, transported to RIAR. And RIAR manufactures vibration packing fuel pin. On the upper endplug welding by pressurized resistance welding method, we worded on the problems such as decision of welding condition by changing the size and crystallization of cladding tube and the design of endplug, and the chucking device remodeling to correspond to the long scale cladding tube welding system (included handling) and of quality assurance method. Especially, use of long scale cladding tube caused problem that bending transformation occurred in cladding tube by welding pressure. However, we solved this problem by shortening the distance of cladding tube colette chuck and pressure receiving, and by putting the sleeve in an internal space of welding machine, losing the bending of cladding tube. Moreover, welding defects were occurred by the difference of an inside state, an inside defect and recrystallization of cladding tube. We solved the problem by inside grinding for the edge of tube, angle beam method by ultrasonic wave, and ultrasonic wave form confirmation. Manufacturing process with long scale cladding tube including heat-treatment to remove combustion return and remaining stress was established besides, Afterwards, welding of ODS cladding tube and upper endplug. As the quality assurance system, we constructed [Documented procedure (referred to JOYO)] based on [Document of the QA plan] by OEC. Welding and inspection were executed by the document procedure. It is thought that the quality assurance method become references for the irradiation test in JOYO in the

Weld analysis and control system

Science.gov (United States)

Kennedy, Larry Z. (Inventor); Rodgers, Michael H. (Inventor); Powell, Bradley W. (Inventor); Burroughs, Ivan A. (Inventor); Goode, K. Wayne (Inventor)

1994-01-01

The invention is a Weld Analysis and Control System developed for active weld system control through real time weld data acquisition. Closed-loop control is based on analysis of weld system parameters and weld geometry. The system is adapted for use with automated welding apparatus having a weld controller which is capable of active electronic control of all aspects of a welding operation. Enhanced graphics and data displays are provided for post-weld analysis. The system provides parameter acquisition, including seam location which is acquired for active torch cross-seam positioning. Torch stand-off is also monitored for control. Weld bead and parent surface geometrical parameters are acquired as an indication of weld quality. These parameters include mismatch, peaking, undercut, underfill, crown height, weld width, puddle diameter, and other measurable information about the weld puddle regions, such as puddle symmetry, etc. These parameters provide a basis for active control as well as post-weld quality analysis and verification. Weld system parameters, such as voltage, current and wire feed rate, are also monitored and archived for correlation with quality parameters.

Fine tuning of dwelling time in friction stir welding for preventing material overheating, weld tensile strength increase and weld nugget size decrease

Directory of Open Access Journals (Sweden)

Mijajlović Miroslav M.

2016-01-01

Full Text Available After successful welding, destructive testing into test samples from Al 2024-T351 friction stir butt welds showed that tensile strength of the weld improve along the joint line, while dimensions of the weld nugget decrease. For those welds, both the base material and the welding tool constantly cool down during the welding phase. Obviously, the base material became overheated during the long dwelling phase what made conditions for creation of joints with the reduced mechanical properties. Preserving all process parameters but varying the dwelling time from 5-27 seconds a new set of welding is done to reach maximal achievable tensile strength. An analytical-numerical-experimental model is used for optimising the duration of the dwelling time while searching for the maximal tensile strength of the welds

Optimum welding condition of 2017 aluminum similar alloy friction welded joints

Energy Technology Data Exchange (ETDEWEB)

Tsujino R.; Ochi, H. [Osaka Inst. of Tech., Osaka (Japan); Morikawa, K. [Osaka Sangyo Univ., Osaka (Japan); Yamaguchi, H.; Ogawa, K. [Osaka Prefecture Univ., Osaka (Japan); Fujishiro, Y.; Yoshida, M. [Sumitomo Metal Technology Ltd., Hyogo (Japan)

2002-07-01

Usefulness of the statistical analysis for judging optimization of the friction welding conditions was investigated by using 2017 aluminum similar alloy, where many samples under fixed welding conditions were friction welded and analyzed statistically. In general, selection of the optimum friction welding conditions for similar materials is easy. However, it was not always the case for 2017 aluminum alloy. For optimum friction welding conditions of this material, it is necessary to apply relatively larger upset pressure to obtain high friction heating. Joint efficiencies obtained under the optimum friction welding conditions showed large shape parameter (m value) of Weibull distribution as well as in the dissimilar materials previously reported. The m value calculated on the small number of data can be substituted for m value on the 30 data. Therefore, m value is useful for practical use in the factory for assuming the propriety of the friction welding conditions. (orig.)

Dual wire welding torch and method

Science.gov (United States)

Diez, Fernando Martinez; Stump, Kevin S.; Ludewig, Howard W.; Kilty, Alan L.; Robinson, Matthew M.; Egland, Keith M.

2009-04-28

A welding torch includes a nozzle with a first welding wire guide configured to orient a first welding wire in a first welding wire orientation, and a second welding wire guide configured to orient a second welding wire in a second welding wire orientation that is non-coplanar and divergent with respect to the first welding wire orientation. A method of welding includes moving a welding torch with respect to a workpiece joint to be welded. During moving the welding torch, a first welding wire is fed through a first welding wire guide defining a first welding wire orientation and a second welding wire is fed through a second welding wire guide defining a second welding wire orientation that is divergent and non-coplanar with respect to the first welding wire orientation.

TIG welding method and TIG welding device

International Nuclear Information System (INIS)

Yoneda, Eishi

1998-01-01

The present invention provides a method of TIG welding for members having different heat capacities including a cladding tube and an end plug of a fuel rod to be used, for example, in a reactor, and a device therefor. Namely, in the TIG welding method, the flow rate of a sealed gas to the side of a member having smaller heat capacity is made greater than that on the side of the member having greater heat capacity bordered on the top end of a welding electrode. Since the sealed gas is jetted being localized relative to the welding electrode, arc is restricted in a region of the member having smaller heat capacity and is increased at a region having a larger heat capacity. As a result, the arc is localized, so that the heat input amount to the region having a large heat capacity is increased, and then a plurality of members at the abutting portion are melted uniformly thereby capable of obtaining a uniform molten pool. A bead is formed at the abutting portion thereby capable of obtaining a welded portion with less unevenness and having large strength. (I.S.)

Sand transportation and reverse patterns over leeward face of sand dune

Science.gov (United States)

Jiang, Hong; Dun, Hongchao; Tong, Ding; Huang, Ning

2017-04-01

Sand saltation has complex interactions with turbulent flow and dune form. Most models of wind-blown sand consider ideal circumstances such as steady wind velocity and a flat surface, and the bulk of data on wind flow and sand transport over an individual dune has focused mostly on the influence of dune shape or inter-dune space on the wind flow, neglecting the effect of morphology on sand saltation, particularly airflow and sand transportation over the leeward slope. Wind flow structures over the leeward slope of sand dunes have a fundamental influence on the organization of sand dunes. In order to understand sand dune dynamics, lee face airflow and sediment transportation should be paid more attention. Previous field observations could not measure turbulent flow structure well because of the limited observation points and the influence of experiment structure on wind field. In addition, the reverse sand particles over leeward face could not be collected by sand trap in field. Numerous field observations could not measure turbulent flow structure because of the limited observation points and the influence of experimental structures on the wind field. In addition, the reverse transport of sand particles over leeward face could not be collected by sand traps in field. Therefore, this paper aims to investigate the turbulent flow structure and sand transport pattern over the leeward slope. A numerical model of sand saltation over slope terrain is constructed, which also considers the coupling effects between air flow and sand particles. The large eddy simulation method is used to model turbulent flow. Sand transport is simulated by tracking the trajectory of each sand particle. The results show that terrain significantly alters the turbulent air flow structure and wind-blown sand movement, especially over the leeward slope. Here, mass flux increases initially and then decreases with height in the reversed flow region in the direction of wind flow, and the mass flux

Experimental investigation on the weld pool formation process in plasma keyhole arc welding

Science.gov (United States)

Van Anh, Nguyen; Tashiro, Shinichi; Van Hanh, Bui; Tanaka, Manabu

2018-01-01

This paper seeks to clarify the weld pool formation process in plasma keyhole arc welding (PKAW). We adopted, for the first time, the measurement of the 3D convection inside the weld pool in PKAW by stereo synchronous imaging of tungsten tracer particles using two sets of x-ray transmission systems. The 2D convection on the weld pool surface was also measured using zirconia tracer particles. Through these measurements, the convection in a wide range of weld pools from the vicinity of the keyhole to the rear region was successfully visualized. In order to discuss the heat transport process in a weld pool, the 2D temperature distribution on the weld pool surface was also measured by two-color pyrometry. The results of the comprehensive experimental measurement indicate that the shear force due to plasma flow is found to be the dominant driving force in the weld pool formation process in PKAW. Thus, heat transport in a weld pool is considered to be governed by two large convective patterns near the keyhole: (1) eddy pairs on the surface (perpendicular to the torch axis), and (2) eddy pairs on the bulk of the weld pool (on the plane of the torch). They are formed with an equal velocity of approximately 0.35 m s-1 and are mainly driven by shear force. Furthermore, the flow velocity of the weld pool convection becomes considerably higher than that of other welding processes, such as TIG welding and GMA welding, due to larger plasma flow velocity.

Study on the stress and strain during welding of plate-to-pipe joint

Energy Technology Data Exchange (ETDEWEB)

Na, S.J.; Kim, H.W.

1986-09-01

In manufacturing of pipe walls for boiler units, distortion can result in pipe-to-pipe joints from the nonuniform expansion and contraction of the weld metal and the adjacent base metal during heating and cooling cycle of the welding process. In this study, the stresses and strains during longitudinal welding of the plate-to-pipe joint were investigated. Using the method of sucessive elastic solution, longitudinal stresses and strains during and after welding were calculated from the information of temperature distributions obtained by Rosenthal's equations. In order to confirm the validity of the numerical results, the temperature and residual stress distributions were measured and compared with the calculated results. In spite of some assumptions, the one-dimensional analytical results of residual stresses were in fairly good agreement with the experimental ones. The residual stresses due to welding of plate-to-pipe joints are tensile near the weld line and compressive in the base metal as in the welding of plates. The amount and distribution of residual stresses were deeply dependent on the heat input ratio of the plate and pipe.

LMFBR steam generators in the United Kingdom

International Nuclear Information System (INIS)

Anderson, R.; Hayden, O.

2002-01-01

Experience has been gained in the UK on the operation of LMFBR Steam Generator Units (SGU) over a period of 20 years from the Dounreay Fast Reactor (DFR) and the Prototype Fast Reactor (PFR). The DFR steam generator featured a double barrier and therefore did not represent a commercial design. PFR, however, faced the challenge of a single wall design and it is experience from this which is most valuable. The PFR reactor went critical in March 1974 and the plant operating history since then has been dominated by experience with leaks in the tube to tube plate welds of the high performance U-tubes SGU's. Operation at high power using the full complement of three secondary sodium circuits was delayed until July 1976 by the occurrence of leaks in the tube to tube plate welds of the superheater and reheater units which are fabricated in stainless steel. Repairs were carried out to the two superheaters and they were returned to service. The reheater tube bundle was removed from circuit after sodium was found to have entered the steam side. When the sodium had been removed and inspection carried out it was decided not to recover the unit. Since 1976 the remaining five stainless steel units have operated satisfactorily. This year a replacement reheater unit has been installed. This is of a new design in 9-Cr-Mo ferritic steel using a sleeve through which the steam tube passes to eliminate the tube to tube plate weld. Despite a few early leaks in evaporator tube to tube plate welds up to 1979, these failures did not initially present a major problem. However, in 1980 the rate of evaporator weld failures increased and despite the successful application of a shot peening process to eliminate stress corrosion failures from the water side of the weld, failures traced to the sodium side continued. A sleeving process was developed for application to complete evaporator units on a production basis with the objective of bypassing the welds at each end of the 500 tubes. The decision

Automatization of welding

International Nuclear Information System (INIS)

Iwabuchi, Masashi; Tomita, Jinji; Nishihara, Katsunori.

1978-01-01

Automatization of welding is one of the effective measures for securing high degree of quality of nuclear power equipment, as well as for correspondence to the environment at the site of plant. As the latest ones of the automatic welders practically used for welding of nuclear power apparatuses in factories of Toshiba and IHI, those for pipes and lining tanks are described here. The pipe welder performs the battering welding on the inside of pipe end as the so-called IGSCC countermeasure and the succeeding butt welding through the same controller. The lining tank welder is able to perform simultaneous welding of two parallel weld lines on a large thin plate lining tank. Both types of the welders are demonstrating excellent performance at the shops as well as at the plant site. (author)

Development and tests of large nuclear turbo-generator welded rotors

International Nuclear Information System (INIS)

Colombie, H.; Thiery, M.; Rotzinger, R.; Pelissou, C.; Tabacco, C.; Fernagut, V.

2015-01-01

Turbo-generators require large forgings for the rotor and it is a worldwide practice to manufacture turbo-generator rotor bodies as single piece forgings. Rotors for nuclear applications (4-pole rotors design, 1500/1800 rpm) require forgings of up to 2.0 m diameter and ultra large ingots with weight more than 500 tons. Nowadays only few forge masters can deliver such forgings in the world. Based on the large welding experience Alstom has gained over decades on steam and gas turbines and Alstom's multi piece shrunk turbo-generator rotors, it was suggested to manufacture 4-pole turbo-generator rotors by welding the shaft from aligned cylindrical forgings. Compared to turbine welded rotors, the shaft of a turbo-generator rotor presents differences linked to dimensions/weight, weld depth and electrical application. The manufacture of a 2 disc model allowed to prove through electrical and mechanical analysis the reliability of the concept as well as the reliability of the manufacturing processes through material tests, micro sections, electrical component tests, weld geometry, welding processes (TIG,SAW,...), weld inspection (Ultrasonic testing, radiographic inspection,...) weld heat treatments and machining. Then a full rotor able to replace a single forging rotor was manufactured in order to validate and prove to potential customers the validity of the welded rotor technology. During the first order from EDF of a welded 900 MW spare rotor, the procedure for the Non Destructive Test on a slotted rotor was developed upon EDF request in order to compare future Non Destructive Testing with the finger print of the new rotor. This complete rotor was delivered to EDF in January 2013. This rotor is in operation in a nuclear unit since November 2013. (authors)

Electric arc welding gun

Science.gov (United States)

Luttrell, Edward; Turner, Paul W.

1978-01-01

This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

A novel weld seam detection method for space weld seam of narrow butt joint in laser welding

Science.gov (United States)

Shao, Wen Jun; Huang, Yu; Zhang, Yong

2018-02-01

Structured light measurement is widely used for weld seam detection owing to its high measurement precision and robust. However, there is nearly no geometrical deformation of the stripe projected onto weld face, whose seam width is less than 0.1 mm and without misalignment. So, it's very difficult to ensure an exact retrieval of the seam feature. This issue is raised as laser welding for butt joint of thin metal plate is widely applied. Moreover, measurement for the seam width, seam center and the normal vector of the weld face at the same time during welding process is of great importance to the welding quality but rarely reported. Consequently, a seam measurement method based on vision sensor for space weld seam of narrow butt joint is proposed in this article. Three laser stripes with different wave length are project on the weldment, in which two red laser stripes are designed and used to measure the three dimensional profile of the weld face by the principle of optical triangulation, and the third green laser stripe is used as light source to measure the edge and the centerline of the seam by the principle of passive vision sensor. The corresponding image process algorithm is proposed to extract the centerline of the red laser stripes as well as the seam feature. All these three laser stripes are captured and processed in a single image so that the three dimensional position of the space weld seam can be obtained simultaneously. Finally, the result of experiment reveals that the proposed method can meet the precision demand of space narrow butt joint.

Narrow gap mechanised arc welding in nuclear components manufactured by AREVA NP

International Nuclear Information System (INIS)

Peigney, A.

2007-01-01

Nuclear components require welds of irreproachable and reproducible quality. Moreover, for a given welding process, productivity requirements lead to reduce the volume of deposited metal and thus to use narrow gap design. In the shop, narrow gap Submerged Arc Welding process (SAW) is currently used on rotating parts in flat position for thicknesses up to 300 mm. Welding is performed with one or two wires in two passes per layer. In Gas Tungsten Arc Welding process (GTAW), multiple applications can be found because this process presents the advantage of allowing welding in all positions. Welding is performed in one or two passes per layer. The process is used in factory and on the nuclear sites for assembling new components but also for replacing components and for repairs. Presently, an increase of productivity of the process is sought through the use of hot wire and/or two wires. Concerning Gas Metal Arc Welding process (GMAW), its use is growing for nuclear components, including narrow gap applications. This process, limited in its applications in the past on account of the defects it generated, draws benefit from the progress of the welding generators. Then it is possible to use this efficient process for high security components such as those of nuclear systems. It is to be noted that the process is applicable in the various welding positions as it is the case for GTAW, while being more efficient than the latter. This paper presents the state of the art in the use of narrow gap mechanised arc welding processes by AREVA NP units. (author) [fr

Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

Energy Technology Data Exchange (ETDEWEB)

R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

2011-12-01

The U.S. Department of Energy selected the high temperature gas-cooled reactor as the basis for the Next Generation Nuclear Plant (NGNP). The NGNP will demonstrate the use of nuclear power for electricity, hydrogen production, and process heat applications. The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. An intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding. This report describes the preliminary results of a scoping study that evaluated the diffusion welding process parameters and the resultant mechanical properties of diffusion welded joints using Alloy 800H. The long-term goal of the program is to progress towards demonstration of small heat exchanger unit cells fabricated with diffusion welds. Demonstration through mechanical testing of the unit cells will support American Society of Mechanical Engineers rules and standards development, reduce technical risk, and provide proof of concept for heat exchanger fabrication methods needed to deploy heat exchangers in several potential NGNP configurations.1 Researchers also evaluated the usefulness of modern thermodynamic and diffusion computational tools (Thermo-Calc and Dictra) in optimizing the parameters for diffusion welding of Alloy 800H. The modeling efforts suggested a temperature of 1150 C for 1 hour with an applied pressure of 5 MPa using 15 {micro}m nickel foil as joint filler to reduce chromium oxidation on the welded surfaces. Good agreement between modeled and experimentally determined concentration gradients was achieved

Investigation into Variations of Welding Residual Stresses and Redistribution Behaviors for Different Repair Welding Widths

International Nuclear Information System (INIS)

Park, Chiyong; Lee, Hweesueng; Huh, Namsu

2014-01-01

In this study, we investigated the variations in welding residual stresses in dissimilar metal butt weld due to width of repair welding and re-distribution behaviors resulting from similar metal welding (SMW) and mechanical loading. To this end, detailed two-dimensional axi-symmetric finite element (FE) analyses were performed considering five different repair welding widths. Based on the FE results, we first evaluated the welding residual stress distributions in repair welding. We then investigated the re-distribution behaviors of the residual stresses due to SMW and mechanical loads. It is revealed that large tensile welding residual stresses take place in the inner surface and that its distribution is affected, provided repair welding width is larger than certain value. The welding residual stresses resulting from repair welding are remarkably reduced due to SMW and mechanical loading, regardless of the width of the repair welding

Certification of a weld produced by friction stir welding

Science.gov (United States)

Obaditch, Chris; Grant, Glenn J

2013-10-01

Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

Laser beam welding and friction stir welding of 6013-T6 aluminium alloy sheet

International Nuclear Information System (INIS)

Braun, R.; Dalle Donne, C.; Staniek, G.

2000-01-01

Butt welds of 1.6 mm thick 6013-T6 sheet were produced using laser beam welding and friction stir welding processes. Employing the former joining technique, filler powders of the alloys Al-5%Mg and Al-12%Si were used. Microstructure, hardness profiles, tensile properties and the corrosion behaviour of the welds in the as-welded condition were investigated. The hardness in the weld zone was lower compared to that of the base material in the peak-aged temper. Hardness minima were measured in the fusion zone and in the thermomechanically affected zone for laser beam welded and friction stir welded joints, respectively. Metallographic and fractographic examinations revealed pores in the fusion zone of the laser beam welds. Porosity was higher in welds made using the filler alloy Al-5%Mg than using the filler metal Al-12%Si. Transmission electron microscopy indicated that the β '' (Mg 2 Si) hardening precipitates were dissolved in the weld zone due to the heat input of the joining processes. Joint efficiencies achieved for laser beam welds depended upon the filler powders, being about 60 and 80% using the alloys Al-5%Mg and Al-12%Si, respectively. Strength of the friction stir weld approached over 80% of the ultimate tensile strength of the 6013-T6 base material. Fracture occurred in the region of hardness minima unless defects in the weld zone led to premature failure. The heat input during welding did not cause a degradation of the corrosion behaviour of the welds, as found in continuous immersion tests in an aqueous chloride-peroxide solution. In contrast to the 6013-T6 parent material, the weld zone was not sensitive to intergranular corrosion. Alternate immersion tests in 3.5% NaCl solution indicated high stress corrosion cracking resistance of the joints. For laser beam welded sheet, the weld zone of alternately immersed specimens suffered severe degradation by pitting and intergranular corrosion, which may be associated with galvanic coupling of filler metal and

Process for quality assurance of welded joints for electrical resistance point welding

International Nuclear Information System (INIS)

Schaefer, R.; Singh, S.

1977-01-01

In order to guarantee the reproducibility of welded joints of even quality (above all in the metal working industry), it is proposed that before starting resistance point welding, a preheating current should be allowed to flow at the site of the weld. A given reduction of the total resistance at the site of the weld should effect the time when the preheating current is switched over to welding current. This value is always predetermined empirically. Further possibilities of controlling the welding process are described, where the measurement of thermal expansion of the parts is used. A standard welding time is given. The rated course of electrode movement during the process can be predicted and a running comparison of nominal and actual values can be carried out. (RW) [de

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

DEFF Research Database (Denmark)

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

2015-01-01

Weldability of a new lightweight sandwich material, LITECOR®, by resistance spot welding is analyzed by experiments and numerical simulations. The spot welding process is accommodated by a first pulse squeezing out the non-conductive polymer core of the sandwich material locally to allow metal......–metal contact. This is facilitated by the use of a shunt tool and is followed by a second pulse for the actual spot welding and nugget formation. A weldability lobe in the time-current space of the second pulse reveals a process window of acceptable size for automotive assembly lines. Weld growth curves...... with experimental results in the range of welding parameters leading to acceptable weld nugget sizes. The validated accuracy of the commercially available software proves the tool useful for assisting the choice of welding parameters....

Validation of Weld Residual Stress Modeling in the NRC International Round Robin Study

International Nuclear Information System (INIS)

Mullins, Jonathan; Gunnars, Jens

2013-01-01

Weld residual stresses (WRS) have a large influence on the behavior of cracks growing under normal operation loads and on the leakage flow from a through-wall crack. Accurate prediction on weld residual stresses is important to make proper decisions when cracks in weld joints are detected. During the latest years, there has been a strong development in both analytical procedures to numerically determine WRS and experimental measurements of WRS. The USNRC (United States Nuclear Regulatory Commission) has formed a program for validation of WRS predictions through comparison of numerically calculated residual stress fields in dissimilar welds measured by different methods. The present report describes the results of the project with special focus on the contribution from Inspecta Technology. Objectives: The principal objective of the project is to compare different WRS predictions for a dissimilar pipe weld with careful measurements on a mock-up weld. The results of the project will make it possible to make recommendations on computational procedures for WRS in dissimilar metal welds. Results: It is concluded that numerical analysis of weld residual stresses using the finite element method is very useful for the estimation of weld residual stresses in complex geometries and dissimilar metal welds. The validation study increases the understanding of uncertainties associated with different modeling approaches and helps to identify the most sensitive parameters

Residual stress by repair welds

International Nuclear Information System (INIS)

Mochizuki, Masahito; Toyoda, Masao

2003-01-01

Residual stress by repair welds is computed using the thermal elastic-plastic analysis with phase-transformation effect. Coupling phenomena of temperature, microstructure, and stress-strain fields are simulated in the finite-element analysis. Weld bond of a plate butt-welded joint is gouged and then deposited by weld metal in repair process. Heat source is synchronously moved with the deposition of the finite-element as the weld deposition. Microstructure is considered by using CCT diagram and the transformation behavior in the repair weld is also simulated. The effects of initial stress, heat input, and weld length on residual stress distribution are studied from the organic results of numerical analysis. Initial residual stress before repair weld has no influence on the residual stress after repair treatment near weld metal, because the initial stress near weld metal releases due to high temperature of repair weld and then stress by repair weld regenerates. Heat input has an effect for residual stress distribution, for not its magnitude but distribution zone. Weld length should be considered reducing the magnitude of residual stress in the edge of weld bead; short bead induces high tensile residual stress. (author)

Standard practice for examination of welds using the alternating current field measurement technique

CERN Document Server

American Society for Testing and Materials. Philadelphia

2007-01-01

1.1 This practice describes procedures to be followed during alternating current field measurement examination of welds for baseline and service-induced surface breaking discontinuities. 1.2 This practice is intended for use on welds in any metallic material. 1.3 This practice does not establish weld acceptance criteria. 1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each system might not be exact equivalents; therefore, each system shall be used independently of the other. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Handbook of Plastic Welding

DEFF Research Database (Denmark)

Islam, Aminul

The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plastic...... materials and provides an extensive knowhow on the industrial plastic welding process. The objectives of the report include: - Provide the general knowhow of laser welding for the beginners - Summarize the state-of-the-art information on the laser welding of plastics - Find the technological limits in terms...... of design, materials and process - Find the best technology, process and machines adaptive to Sonion’s components - Provide the skills to Sonion’s Design Engineers for successful design of the of the plastic components suitable for the laser welding The ultimate goal of this report is to serve...

Boosting Active Contours for Weld Pool Visual Tracking in Automatic Arc Welding

DEFF Research Database (Denmark)

Liu, Jinchao; Fan, Zhun; Olsen, Søren Ingvor

2015-01-01

Detecting the shape of the non-rigid molten metal during welding, so-called weld pool visual sensing, is one of the central tasks for automating arc welding processes. It is challenging due to the strong interference of the high-intensity arc light and spatters as well as the lack of robust...... approaches to detect and represent the shape of the nonrigid weld pool. We propose a solution using active contours including an prior for the weld pool boundary composition. Also, we apply Adaboost to select a small set of features that captures the relevant information. The proposed method is applied...... to weld pool tracking and the presented results verified its feasibility....

Analysis of welding distortion due to narrow-gap welding of upper port plug

International Nuclear Information System (INIS)

Biswas, Pankaj; Mandal, N.R.; Vasu, Parameswaran; Padasalag, Shrishail B.

2010-01-01

Narrow-gap welding is a low distortion welding process. This process allows very thick plates to be joined using fewer weld passes as compared to conventional V-groove or double V-groove welding. In case of narrow-gap arc welding as the heat input and weld volume is low, it reduces thermal stress leading to reduction of both residual stress and distortion. In this present study the effect of narrow-gap welding was studied on fabrication of a scaled down port plug in the form of a trapezoidal box made of 10 mm thick mild steel (MS) plates using gas tungsten arc welding (GTAW). Inherent strain method was used for numerical prediction of resulting distortions. The numerical results compared well with that of the experimentally measured distortion. The validated numerical scheme was used for prediction of weld induced distortion due to narrow-gap welding of full scale upper port plug made of 60 mm thick SS316LN material as is proposed for use in ITER project. It was observed that it is feasible to fabricate the said port plug keeping the distortions minimum within about 7 mm using GTAW for root pass welding followed by SMAW for filler runs.

Welding processes handbook

CERN Document Server

Weman, Klas

2003-01-01

Deals with the main commercially significant and commonly used welding processes. This title takes the student or novice welder through the individual steps involved in each process in an easily understood way. It covers many of the requirements referred to in European Standards including EN719, EN 729, EN 729 and EN 287.$bWelding processes handbook is a concise, explanatory guide to the main commercially significant and commonly-used welding processes. It takes the novice welder or student through the individual steps involved in each process in a clear and easily understood way. It is intended to provide an up-to-date reference to the major applications of welding as they are used in industry. The contents have been arranged so that it can be used as a textbook for European welding courses in accordance with guidelines from the European Welding Federation. Welding processes and equipment necessary for each process are described so that they can be applied to all instruction levels required by the EWF and th...

Performance of sand filters for the separations areas at the Savannah River Laboratory

International Nuclear Information System (INIS)

Orth, D.A.; Sykes, G.H.; McKibben, J.M.

1981-01-01

Two new large sand filters, 30.5 by 100 m, were constructed and put into service at the Savannah River Plant (SRP) in 1975 and 1976. These units were designed to provide final filtration of process air - one for each of the two separations areas. Eventual flow will be 4950 m 3 /min (205,000 scfm) on each unit when all facilities are connected. They were built as replacements for the original sand filters that began operation in 1954 and 1955. The new filters have been operated in parallel with the old units following partial failure of the old units from acid attack and erosion of the concrete support structure for the sand beds. The design of the new units was based on extensive tests at SRP on characteristics of different sands. The performance of the new filters meets criteria for pressure drop, flow capacity, and efficiency. The efficiencies measured by DOP test are greater than 99.98%. Parallel operation reduces air velocity through the beds, which increases efficiency. A characteristic of sand filter performance has been low apparent efficiency at low input; efficiency increases as the activity input rises. This is attributed to a small entrainment release from the large amount of activity already sorbed on the filter; this release controls and lowers the calculated efficiency at low input. An analysis of efficiency as a function of input activity projects efficiencies greater than 99.99% for large inputs that might be characteristic of large internal accidents. The data indicate that DOP efficiencies can be used in hazards analyses to determine accident consequences. Routine evaluation of filter releases can be used for surveillance to establish that performance is normal at other times

Ultrasonic Stir Welding

Science.gov (United States)

Nabors, Sammy

2015-01-01

NASA Marshall Space Flight Center (MSFC) developed Ultrasonic Stir Welding (USW) to join large pieces of very high-strength metals such as titanium and Inconel. USW, a solid-state weld process, improves current thermal stir welding processes by adding high-power ultrasonic (HPU) energy at 20 kHz frequency. The addition of ultrasonic energy significantly reduces axial, frictional, and shear forces; increases travel rates; and reduces wear on the stir rod, which results in extended stir rod life. The USW process decouples the heating, stirring, and forging elements found in the friction stir welding process allowing for independent control of each process element and, ultimately, greater process control and repeatability. Because of the independent control of USW process elements, closed-loop temperature control can be integrated into the system so that a constant weld nugget temperature can be maintained during welding.

The effects of welded joint characteristics on its properties in HDPE thermal fusion welding

Science.gov (United States)

Dai, Hongbin; Peng, Jun

2017-05-01

In this paper, PE100 pipes with the diameter of 200 mm and the thickness of 11.9 mm were used as material. The welded joints were obtained in different welding pressures with the optimal welding temperature of 220∘C. Reheating process on the welded joints with the temperature of 130∘C was carried out. The joints exhibited X-type, and the cause of X-type joints was discussed. The temperature field in the forming process of welded joints was measured, and tensile and bending tests on welded joints were carried out. The fracture surface of welded joints was observed by scanning electron microscopy (SEM), and crystallinity calculation was taken by X-ray diffraction (XRD). The mechanism of X-type weld profile effects on welded joints properties was analyzed. It was concluded that the mechanical properties of welded joints decrease with the reduced X distance between lines.

Recent advances in the TIG welding process and the application of the welding of nuclear components

International Nuclear Information System (INIS)

Lucas, W.; Males, B.O.

1982-01-01

Recent advances in the field of precision arc welding techniques and infacilities for production of nuclear power plant components arc presented. Of the precision welding techniques, pulsed TIG welding, pulsed plasma arc welding, hot-wire TIG welding, and pulsed inert-gas metal-arc welding. In the field of weld cladding, GMA plasma welding is cited as an alternative to submerged-arc welding with a strip electrode. Transistors and computer-controlled welding systems get a special mention. Applications of TIG welding in the UK are cited, e.g. welding of components for the AGR nuclear power plant and construction of equipment for repair work in feedwater pipes of the MAGNOX reactor. (orig.) [de

WELDING TORCH

Science.gov (United States)

Correy, T.B.

1961-10-01

A welding torch into which water and inert gas are piped separately for cooling and for providing a suitable gaseous atmosphere is described. A welding electrode is clamped in the torch by a removable collet sleeve and a removable collet head. Replacement of the sleeve and head with larger or smaller sleeve and head permits a larger or smaller welding electrode to be substituted on the torch. (AEC)

Welding procedure specification for arc welding of St 52-3N steel plates with covered electrodes

International Nuclear Information System (INIS)

Cvetkovski, S.; Slavkov, D.; Magdeski, J.

2003-01-01

In this paper the results of approval welding technology for arc welding of plates made of St 52-3N steel are presented. Metal arc welding with covered electrode is used welding process. Test specimens are butt welded in different welding positions P A , P F , P C and P D . Before start welding preliminary welding procedure was prepared. After welding of test specimens non destructive and destructive testing was performed. Obtained results were compared with standard DIN 17100 which concerns to chemical composition and mechanical properties of base material. It was confirmed that in all cases mechanical properties of welded joint are higher than those of base material, so preliminary welding procedure (pWTS) can be accepted as welding procedure specification WPS for metal arc welding of St52-3N steel. (Original)

Variant selection of martensites in steel welded joints with low transformation temperature weld metals

International Nuclear Information System (INIS)

Takahashi, Masaru; Yasuda, Hiroyuki Y.

2013-01-01

Highlights: ► We examined the variant selection of martensites in the weld metals. ► We also measured the residual stress developed in the butt and box welded joints. ► 24 martensite variants were randomly selected in the butt welded joint. ► High tensile residual stress in the box welded joint led to the strong variant selection. ► We discussed the rule of the variant selection focusing on the residual stress. -- Abstract: Martensitic transformation behavior in steel welded joints with low transformation temperature weld (LTTW) metal was examined focusing on the variant selection of martensites. The butt and box welded joints were prepared with LTTW metals and 980 MPa grade high strength steels. The residual stress of the welded joints, which was measured by a neutron diffraction technique, was effectively reduced by the expansion of the LTTW metals by the martensitic transformation during cooling after the welding process. In the LTTW metals, the retained austenite and martensite phases have the Kurdjumov–Sachs (K–S) orientation relationship. The variant selection of the martensites in the LTTW metals depended strongly on the type of welded joints. In the butt welded joint, 24 K–S variants were almost randomly selected while a few variants were preferentially chosen in the box welded joint. This suggests that the high residual stress developed in the box welded joint accelerated the formation of specific variants during the cooling process, in contrast to the butt welded joint with low residual stress

Corrosion resistance of «tube – tubesheet» weld joint obtained by friction welding

Directory of Open Access Journals (Sweden)

RIZVANOV Rif Garifovich

2017-08-01

Full Text Available Shell-and-tube heat exchangers are widely applied for implementation of various processes at ventures of fuel and energy complex. Cost of production and reliability of heat exchangers of this type is to a wide extent determined by corresponding characteristics of tube bundle, «tube – tubesheet» is its typical joint in particular when welding operations are used in order to attach tubes to tubesheet in addition to expansion. When manufacturing such equipment of heat-resistant chrome-bearing or chromium-molybdenum steels including steel 15H5M, the process of fixed joint manufacturing gets significantly more complicated and costly due to the necessity to use thermal treatment before, during and after welding (this problem is particularly applicable for manufacturing of large-size equipment. One of the options to exclude thermal treatment from manufacturing process is to use «non-arc» welding methods – laser welding, explosion welding as well as friction welding. Use of each of the welding methods mentioned above during production of heat-exchange equipment has its process challenges and peculiarities. This article gives a comparative analysis of weld structure and distribution of electrode potentials of welded joints and parent metal of the joints simulating welding of tube to tubesheet of steel 15H5M using the following welding methods: shielded manual arc welding, tungsten-arc inert-gas welding and friction welding. Comparative analysis of macro- and microstructures of specific zones of the studied welded joints showed that the joints produced by arc welding methods do not exhibit evident inhomogeneity of the structure after application of thermal treatment which is explained by the correctness of thermal treatment. Joints obtained via friction welding are characterized by structural inhomogeneity of the welded joint zone metal microstructure. The ultra-fine-grained structure obtained as a result of friction welding makes it possible to

The Effect of Weld Reinforcement and Post-Welding Cooling Cycles on Fatigue Strength of Butt-Welded Joints under Cyclic Tensile Loading.

Science.gov (United States)

Araque, Oscar; Arzola, Nelson; Hernández, Edgar

2018-04-12

This research deals with the fatigue behavior of butt-welded joints, by considering the geometry and post-welding cooling cycles, as a result of cooling in quiet air and immersed in water. ASTM A-36 HR structural steel was used as the base metal for the shielded metal arc welding (SMAW) process with welding electrode E6013. The welding reinforcement was 1 mm and 3 mm, respectively; axial fatigue tests were carried out to determine the life and behavior in cracks propagation of the tested welded joints, mechanical characterization tests of properties in welded joints such as microhardness, Charpy impact test and metallographic analysis were carried out. The latter were used as input for the analysis by finite elements which influence the initiation and propagation of cracks and the evaluation of stress intensity factors (SIF). The latter led to obtaining the crack propagation rate and the geometric factor. The tested specimens were analyzed, by taking photographs of the cracks at its beginning in order to make a count of the marks at the origin of the crack. From the results obtained and the marks count, the fatigue crack growth rate and the influence of the cooling media on the life of the welded joint are validated, according to the experimental results. It can be concluded that the welded joints with a higher weld reinforcement have a shorter fatigue life. This is due to the stress concentration that occurs in the vicinity of the weld toe.

Distortion Control during Welding

NARCIS (Netherlands)

Akbari Pazooki, A.M.

2014-01-01

The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ

Arc-weld pool interactions

International Nuclear Information System (INIS)

Glickstein, S.S.

1978-08-01

The mechanisms involved in arc-weld pool interactions are extremely complex and no complete theory is presently available to describe much of the phenomena observed during welding. For the past several years, experimental and analytical studies have been undertaken at the Bettis Atomic Power Laboratory to increase basic understanding of the gas tungsten arc welding process. These studies have included experimental spectral analysis of the arc in order to determine arc temperature and analytical modeling of the arc and weld puddle. The investigations have been directed toward determining the cause and effects of variations in the energy distribution incident upon the weldment. In addition, the effect of weld puddle distortion on weld penetration was investigated, and experimental and analytical studies of weld process variables have been undertaken to determine the effects of the variables upon weld penetration and configuration. A review of the results and analysis of these studies are presented

Welding electrode for peripheral welds of A-1 reactor pressure vessel

International Nuclear Information System (INIS)

Lakatos, L.

1975-01-01

The properties are outlined of the VUZ-AC1-52 welding electrode used in welding the Bohunice A-1 reactor pressure vessel. The mechanical properties of welded joints after the final thermal treatment are summed up. (J.K.)

Evaluating process origins of sand-dominated fluvial stratigraphy

Science.gov (United States)

Chamberlin, E.; Hajek, E. A.

2015-12-01

Sand-dominated fluvial stratigraphy is often interpreted as indicating times of relatively slow subsidence because of the assumption that fine sediment (silt and clay) is reworked or bypassed during periods of low accommodation. However, sand-dominated successions may instead represent proximal, coarse-grained reaches of paleo-river basins and/or fluvial systems with a sandy sediment supply. Differentiating between these cases is critical for accurately interpreting mass-extraction profiles, basin-subsidence rates, and paleo-river avulsion and migration behavior from ancient fluvial deposits. We explore the degree to which sand-rich accumulations reflect supply-driven progradation or accommodation-limited reworking, by re-evaluating the Castlegate Sandstone (Utah, USA) and the upper Williams Fork Formation (Colorado, USA) - two Upper Cretaceous sandy fluvial deposits previously interpreted as having formed during periods of relatively low accommodation. Both units comprise amalgamated channel and bar deposits with minor intra-channel and overbank mudstones. To constrain relative reworking, we quantify the preservation of bar deposits in each unit using detailed facies and channel-deposit mapping, and compare bar-deposit preservation to expected preservation statistics generated with object-based models spanning a range of boundary conditions. To estimate the grain-size distribution of paleo-sediment input, we leverage results of experimental work that shows both bed-material deposits and accumulations on the downstream side of bars ("interbar fines") sample suspended and wash loads of active flows. We measure grain-size distributions of bar deposits and interbar fines to reconstruct the relative sandiness of paleo-sediment supplies for both systems. By using these novel approaches to test whether sand-rich fluvial deposits reflect river systems with accommodation-limited reworking and/or particularly sand-rich sediment loads, we can gain insight into large

Quantification of Microtexture at Weld Nugget of Friction Stir-Welded Carbon Steel

Science.gov (United States)

Husain, Md M.; Sarkar, R.; Pal, T. K.; Ghosh, M.; Prabhu, N.

2017-05-01

Friction stir welding of C-Mn steel was carried out under 800-1400 rpm tool rotation. Tool traversing speed of 50 mm/min remained same for all joints. Effect of thermal state and deformation on texture and microstructure at weld nugget was investigated. Weld nugget consisted of ferrite + bainite/Widmanstatten ferrite with different matrix grain sizes depending on peak temperature. A texture around ( ϕ 2 = 0°, φ = 30°, ϕ 2 = 45°) was developed at weld nugget. Grain boundary misorientation at weld nugget indicated that continuous dynamic recrystallization influenced the development of fine equiaxed grain structure. Pole figures and orientation distribution function were used to determine crystallographic texture at weld nugget and base metal. Shear texture components D1, D2 and F were present at weld nugget. D1 shear texture was more prominent among all. Large number of high-angle grain boundaries ( 60-70%) was observed at weld nugget and was the resultant of accumulation of high amount of dislocation, followed by subgrain formation.

Nickel-base alloy overlay weld with improved ultrasonic flaw detection by magnetic stirring welding

International Nuclear Information System (INIS)

Takashi, Hirano; Kenji, Hirano; Masayuki, Watando; Takahiro, Arakawa; Minoru, Maeda

2001-01-01

Ultrasonic flaw detection is more difficult in Nickel-base alloy welds containing dendrites owing to the decrease ultrasonic transmissibility they cause. The present paper discusses application of magnetic stirring welding as a means for reducing dendrite growth with consequent improvement in ultrasonic transmissibility. Single pass and multi-pass welding tests were conducted to determine optimal welding conditions. By PT and macro observation subsequent to welding was carried out, optimal operation conditions were clarified. Overlay welding tests and UT clearly indicated ultrasonic beam transmissibility in overlay welds to be improved and detection capacity to be greater through application of magnetic stirring welding. Optimal operation conditions were determined based on examination of temper bead effects in the heat affected zone of low alloy steel by application of magnetic stirring welding to the butt welded joints between low alloy and stainless steel. Hardness in this zone of low alloy steel after the fourth layer was less than 350 HV. (author)

Effect of weld spacing on microstructure and mechanical properties of CLAM electron beam welding joints

Energy Technology Data Exchange (ETDEWEB)

Zhai, Yutao; Huang, Bo, E-mail: aufa0007@163.com; Zhang, Junyu; Zhang, Baoren; Liu, Shaojun; Huang, Qunying

2016-11-15

Highlights: • The welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding, and a simplified model of CLAM sheet was proposed. • The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). • The effect of the welding thermal cycle was significantly when the weld spacings were smaller than 4 mm. • When the weld spacing was small enough, the original microstructures would be fragmented with the high heat input. - Abstract: China low activation martensitic (CLAM) steel has been chosen as the primary structural material in the designs of dual function lithium-lead (DFLL) blanket for fusion reactors, China helium cooled ceramic breeder (HCCB) test blanket module (TBM) for ITER and China fusion engineering test reactor (CFETR) blanket. The cooling components of the blankets are designed with high density cooling channels (HDCCs) to remove the high nuclear thermal effectively. Hence, the welding spacing among the channels are small. In this paper, the welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding (EBW). The weld spacing was designed to be 2 mm, 3 mm, 4 mm, 6 mm and 8 mm. The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). The PWHT is tempering at 740 °C for 120 min. The results showed that the grain size in the heat affected zone (HAZ) increased with the increasing weld spacing, and the joint with small weld spacing had a better performance after PWHT. This work would give useful guidance to improve the preparation of the cooling components of blanket.

Capabilities of infrared weld monitor

Energy Technology Data Exchange (ETDEWEB)

Sanders, P.G.; Keske, J.S.; Leong, K.H.; Kornecki, G.

1997-11-01

A non-obtrusive pre-aligned, solid-state device has been developed to monitor the primary infrared emissions during laser welding. The weld monitor output is a 100-1000 mV signal that depends on the beam power and weld characteristics. The DC level of this signal is related to weld penetration, while AC portions of the output can be correlated with surface irregularities and part misalignment or contamination. Changes in DC behavior are also noted for both full and deep penetration welds. Full penetration welds are signified by an abrupt reduction in the weld monitor output. Bead on plate welds were made on steel, aluminum, and magnesium with both a CW CO{sub 2} laser and a pulsed Nd:YAG laser to explore the relationships between the weld characteristics and the weld monitor output.

Welding overlay analysis of dissimilar metal weld cracking of feedwater nozzle

International Nuclear Information System (INIS)

Tsai, Y.L.; Wang, Li. H.; Fan, T.W.; Ranganath, Sam; Wang, C.K.; Chou, C.P.

2010-01-01

Inspection of the weld between the feedwater nozzle and the safe end at one Taiwan BWR showed axial indications in the Alloy 182 weld. The indication was sufficiently deep that continued operation could not be justified considering the crack growth for one cycle. A weld overlay was decided to implement for restoring the structural margin. This study reviews the cracking cases of feedwater nozzle welds in other nuclear plants, and reports the lesson learned in the engineering project of this weld overlay repair. The overlay design, the FCG calculation and the stress analysis by FEM are presented to confirm that the Code Case structural margins are met. The evaluations of the effect of weld shrinkage on the attached feedwater piping are also included. A number of challenges encountered in the engineering and analysis period are proposed for future study.

Multi-physics modeling and numerical simulation of weld pool in GTA welding

International Nuclear Information System (INIS)

Nguyen, Minh-Chien

2015-01-01

In this work, we develop a 3D physical and numerical model of the GTA (Gas Tungsten Arc) welding process in order to predict, for given welding parameters, useful quantities for the designer of welded assembly: weld bead shape, fluid flow in the weld pool as well as thermal distribution in the work piece. The model is developed in the Cast3M (http://www-cast3m.cea.fr/) finite element software and takes into account the main physical phenomena acting in the work piece and particularly in the weld pool, subject to source terms modeling the arc part of the welding process. A steady solution of this model is thought for and involves the coupling of the nonlinear thermohydraulics and electromagnetic equations together with the displacement of the deformable free surface of the weld pool. A first step in the development consisted in modeling the electromagnetic phenomena with two different numerical methods, in comparing the numerical results obtained with those of the literature and in quantifying the importance of the Lorentz force and the Joule effect compared to the other mechanical and thermal sources by computing power balances. Then, in order to assess the predictive capability of the model, simulations of various welding configurations are performed: variation in the chemical composition of the material, of the welding speed, of the prescribed arc pressure and of the welding positions, which is a focus of this work, are studied. A good agreement is obtained between the results of our model and other experimental and numerical results of the literature. Eventually, a model accounting for metal filling is proposed and its results are discussed. Thus, our complete model can be seen as a solid foundation towards future totally-coupled 3D welding models including the arc and it will be included in WPROCESS the in-house CEA software dedicated to the numerical simulation of welding. (author) [fr

Detecting flaws in welds

International Nuclear Information System (INIS)

Woodacre, A.; Lawton, H.

1979-01-01

An apparatus and a method for detecting flaws in welds in a workpiece, the portion of the workpiece containing the weld is maintained at a constant temperature and the weld is scanned by an infra red detector. The weld is then scanned again with the workpiece in contact with a cooling probe to produce a steeper temperature gradient across the weld. Comparison of the signals produced by each scan reveals the existence of defects in the welds. The signals may be displayed on an oscilloscope and the display may be observed by a TV camera and recorded on videotape. (UK)

Multipass autogenous electron beam welding

International Nuclear Information System (INIS)

Murphy, J.L.; Mustaleski, T.M. Jr.; Watson, L.C.

1986-01-01

A multipass, autogenous welding procedure was developed for 7.6 mm (0.3 in.) wall thickness Type 304L stainless steel cylinders. The joint geometry has a 1.5 mm (0.06 in.) root-face width and a rectangular stepped groove that is 0.762 mm (0.03 in.) wide at the top of the root face and extends 1.5 mm in height, terminating into a groove width of 1.27 mm which extends to the outside of the 1.27 mm high weld-boss. One weld pass is made on the root, three passes on the 0.762 mm wide groove and three passes to complete the weld. Multipass, autogenous, electron beam welds maintain the characteristic high depth-to-width ratios and low heat input of single-pass, electron beam welds. The increased part distortion (which is still much less than from arc processes) in multipass weldments is corrected by a preweld machined compensation. Mechanical properties of multipass welds compare well with single-pass welds. The yield strength of welds in aluminum alloy 5083 is approximately the same for single-pass or multipass electron beam and gas, metal-arc welds. The incidence and size of porosity is less in multipass electron beam welding of aluminum as compared to gas, metal-arc welds. The multipass, autogenous, electron beam welding method has proven to be a reliable way to make some difficult welds in multilayer parts or in an instance where inside part temperature or weld underbead must be controlled and weld discontinuities must be minimized

The use of field indentation microprobe in measuring mechanical properties of welds

International Nuclear Information System (INIS)

Haggag, F.M.; Wong, H.; Alexander, D.J.; Nanstad, R.K.

1989-01-01

A field indentation microprobe (FIM) was conceived for evaluating the structural integrity of metallic components (including base metal, welds, and heat-affected zones) in situ in a nondestructive manner. The FIM consists of an automated ball indentation (ABI) unit for determining the mechanical properties (yield strength, flow properties, estimates of fracture toughness, etc.) and a nondestructive evaluation (NDE) unit (consisting of ultrasonic transducers and a video camera) for determining the physical properties such as crack size, material pileup around indentation, and residual stress presence and orientation. The laboratory version used in this work performs only ABI testing. ABI tests were performed on stainless steel base metal (type 316L), heat-affected zone, and welds (type 308). Excellent agreement was obtained between yield strength and flow properties (true-stress/true-plastic-strain curve) measured by the ABI tests and those from uniaxial tensile tests conducted on 308 stainless steel welds, thermally aged at 343/degree/C for different times, and on the base material. 4 refs., 17 figs

Reclaimability of the spent sand mixture – sand with bentonite – sand with furfuryl resin

Directory of Open Access Journals (Sweden)

J. Dańko

2011-04-01

Full Text Available Introduction of new binding materials and new technologies of their hardening in casting moulds and cores production requires theapplication of reclamation methods adequate to their properties as well as special devices realizing tasks. The spent sands circulationsystem containing the same kind of moulding and core sands is optimal from the point of view of the expected reclamation results.However, in the face of a significant variability of applied technologies and related to them various reclamation methods, the need - of theobtained reclamation products assessment on the grounds of systematic criteria and uniform bases – arises, with a tendency of indicatingwhich criteria are the most important for the given sand system. The reclaimability results of the mixture of the spent moulding sand withGeko S bentonite and the spent core sand with the Kaltharz 404U resin hardened by acidic hardener 100 T3, are presented in the paper.Investigations were performed with regard to the estimation of an influence of core sands additions (10 –25% on the reclaimed materialquality. Dusts and clay content in the reclaim, its chemical reaction (pH and ignition loss were estimated. The verification of the reclaiminstrumental assessment was performed on the basis of the technological properties estimation of moulding sand with bentonite, where the reclaimed material was used as a matrix.

Barley root hair growth and morphology in soil, sand, and water solution media and relationship with nickel toxicity.

Science.gov (United States)

Lin, Yanqing; Allen, Herbert E; Di Toro, Dominic M

2016-08-01

Barley, Hordeum vulgare (Doyce), was grown in the 3 media of soil, hydroponic sand solution (sand), and hydroponic water solution (water) culture at the same environmental conditions for 4 d. Barley roots were scanned, and root morphology was analyzed. Plants grown in the 3 media had different root morphology and nickel (Ni) toxicity response. Root elongations and total root lengths followed the sequence soil > sand > water. Plants grown in water culture were more sensitive to Ni toxicity and had greater root hair length than those from soil and sand cultures, which increased root surface area. The unit root surface area as root surface area per centimeter of length of root followed the sequence water > sand > soil and was found to be related with root elongation. Including the unit root surface area, the difference in root elongation and 50% effective concentration were diminished, and percentage of root elongations can be improved with a root mean square error approximately 10% for plants grown in different media. Because the unit root surface area of plants in sand culture is closer to that in soil culture, the sand culture method, not water culture, is recommended for toxicity parameter estimation. Environ Toxicol Chem 2016;35:2125-2133. © 2016 SETAC. © 2016 SETAC.

Influence of the arc plasma parameters on the weld pool profile in TIG welding

Science.gov (United States)

Toropchin, A.; Frolov, V.; Pipa, A. V.; Kozakov, R.; Uhrlandt, D.

2014-11-01

Magneto-hydrodynamic simulations of the arc and fluid simulations of the weld pool can be beneficial in the analysis and further development of arc welding processes and welding machines. However, the appropriate coupling of arc and weld pool simulations needs further improvement. The tungsten inert gas (TIG) welding process is investigated by simulations including the weld pool. Experiments with optical diagnostics are used for the validation. A coupled computational model of the arc and the weld pool is developed using the software ANSYS CFX. The weld pool model considers the forces acting on the motion of the melt inside and on the surface of the pool, such as Marangoni, drag, electromagnetic forces and buoyancy. The experimental work includes analysis of cross-sections of the workpieces, highspeed video images and spectroscopic measurements. Experiments and calculations have been performed for various currents, distances between electrode and workpiece and nozzle diameters. The studies show the significant impact of material properties like surface tension dependence on temperature as well as of the arc structure on the weld pool behaviour and finally the weld seam depth. The experimental weld pool profiles and plasma temperatures are in good agreement with computational results.

Influence of the arc plasma parameters on the weld pool profile in TIG welding

International Nuclear Information System (INIS)

Toropchin, A; Frolov, V; Pipa, A V; Kozakov, R; Uhrlandt, D

2014-01-01

Magneto-hydrodynamic simulations of the arc and fluid simulations of the weld pool can be beneficial in the analysis and further development of arc welding processes and welding machines. However, the appropriate coupling of arc and weld pool simulations needs further improvement. The tungsten inert gas (TIG) welding process is investigated by simulations including the weld pool. Experiments with optical diagnostics are used for the validation. A coupled computational model of the arc and the weld pool is developed using the software ANSYS CFX. The weld pool model considers the forces acting on the motion of the melt inside and on the surface of the pool, such as Marangoni, drag, electromagnetic forces and buoyancy. The experimental work includes analysis of cross-sections of the workpieces, highspeed video images and spectroscopic measurements. Experiments and calculations have been performed for various currents, distances between electrode and workpiece and nozzle diameters. The studies show the significant impact of material properties like surface tension dependence on temperature as well as of the arc structure on the weld pool behaviour and finally the weld seam depth. The experimental weld pool profiles and plasma temperatures are in good agreement with computational results

Numerical weld modeling - a method for calculating weld-induced residual stresses

International Nuclear Information System (INIS)

Fricke, S.; Keim, E.; Schmidt, J.

2001-01-01

In the past, weld-induced residual stresses caused damage to numerous (power) plant parts, components and systems (Erve, M., Wesseling, U., Kilian, R., Hardt, R., Bruemmer, G., Maier, V., Ilg, U., 1994. Cracking in Stabilized Austenitic Stainless Steel Piping of German Boiling Water Reactors - Characteristic Features and Root Causes. 20. MPA-Seminar 1994, vol. 2, paper 29, pp.29.1-29.21). In the case of BWR nuclear power plants, this damage can be caused by the mechanism of intergranular stress corrosion cracking in austenitic piping or the core shroud in the reactor pressure vessel and is triggered chiefly by weld-induced residual stresses. One solution of this problem that has been used in the past involves experimental measurements of residual stresses in conjunction with weld optimization testing. However, the experimental analysis of all relevant parameters is an extremely tedious process. Numerical simulation using the finite element method (FEM) not only supplements this method but, in view of modern computer capacities, is also an equally valid alternative in its own right. This paper will demonstrate that the technique developed for numerical simulation of the welding process has not only been properly verified and validated on austenitic pipe welds, but that it also permits making selective statements on improvements to the welding process. For instance, numerical simulation can provide information on the starting point of welding for every weld bead, the effect of interpass cooling as far as a possible sensitization of the heat affected zone (HAZ) is concerned, the effect of gap width on the resultant weld residual stresses, or the effect of the 'last pass heat sink welding' (welding of the final passes while simultaneously cooling the inner surface with water) producing compressive stresses in the root area of a circumferential weld in an austenitic pipe. The computer program FERESA (finite element residual stress analysis) was based on a commercially

Development of Preemptive Repair Technology for Alloy 600 J-Groove Welds of Reactor Vessel Upper Head CEDM Nozzles

Energy Technology Data Exchange (ETDEWEB)

Jung, Kwang Woon; Lee, Jang Wook; Cho, Ki Hyun; Choi, Kwang Min; Choi, Dong Chul; Cho, Sang Beum; Cho, Hong Seok [KEPCO, Daejeon (Korea, Republic of)

2016-05-15

After 2000, PWSCC in numerous NPPs around the world has been generated, and recently, PWSCC in several CEDM nozzles of domestic NPP Hanbit Unit 3 and 4 was founded and repaired with embedded flaw repair(EFR) welding method by Westinghouse. In this study, development status of EFR equipment and basic experimental results for preventive PWSCC of RVUH CEDM nozzles will be introduced. The development of EFR seal welding equipment and welding process for the preemptive repair with original Alloy 600 J-Groove welds of RVUHP was conducted. The EFR welding equipment was tested to be possible seal welding to track J-Groove welds with three dimensional curved surfaces and OD penetration with vertical welding position. Through several BOP and overlay welding experiments, it was verified that good weld beads with no defects, such as cracks, spatter, undercut at the stable welding conditions with heat input of 27.4-32.5 KJ/in were well produced. Consequently, it is expected that the EFR seal welding technique will be applicable on the site.

Automatic welding of fuel elements

International Nuclear Information System (INIS)

Briola, J.

1958-01-01

The welding process depends on the type of fuel element, the can material and the number of cartridges to be welded: - inert-gas welding (used for G2 and the 1. set of EL3), - inert atmosphere arc welding (used for welding uranium and zirconium), - electronic welding (used for the 2. set of EL3 and the tank of Proserpine). (author) [fr

Vision-based weld pool boundary extraction and width measurement during keyhole fiber laser welding

Science.gov (United States)

Luo, Masiyang; Shin, Yung C.

2015-01-01

In keyhole fiber laser welding processes, the weld pool behavior is essential to determining welding quality. To better observe and control the welding process, the accurate extraction of the weld pool boundary as well as the width is required. This work presents a weld pool edge detection technique based on an off axial green illumination laser and a coaxial image capturing system that consists of a CMOS camera and optic filters. According to the difference of image quality, a complete developed edge detection algorithm is proposed based on the local maximum gradient of greyness searching approach and linear interpolation. The extracted weld pool geometry and the width are validated by the actual welding width measurement and predictions by a numerical multi-phase model.

Automatic welding machine for piping

International Nuclear Information System (INIS)

Yoshida, Kazuhiro; Koyama, Takaichi; Iizuka, Tomio; Ito, Yoshitoshi; Takami, Katsumi.

1978-01-01

A remotely controlled automatic special welding machine for piping was developed. This machine is utilized for long distance pipe lines, chemical plants, thermal power generating plants and nuclear power plants effectively from the viewpoint of good quality control, reduction of labor and good controllability. The function of this welding machine is to inspect the shape and dimensions of edge preparation before welding work by the sense of touch, to detect the temperature of melt pool, inspect the bead form by the sense of touch, and check the welding state by ITV during welding work, and to grind the bead surface and inspect the weld metal by ultrasonic test automatically after welding work. The construction of this welding system, the main specification of the apparatus, the welding procedure in detail, the electrical source of this welding machine, the cooling system, the structure and handling of guide ring, the central control system and the operating characteristics are explained. The working procedure and the effect by using this welding machine, and the application to nuclear power plants and the other industrial field are outlined. The HIDIC 08 is used as the controlling computer. This welding machine is useful for welding SUS piping as well as carbon steel piping. (Nakai, Y.)

Laser welding to expand the allowable gap in bore welding for ITER blanket hydraulic connection

Energy Technology Data Exchange (ETDEWEB)

Tanigawa, Hisashi, E-mail: tanigawa.hisashi@jaea.go.jp; Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi

2015-10-15

For application to bore welding of hydraulic connection in the ITER blanket module, laser welding presents the following benefits: low weld heat input is preferred for re-welding of the irradiated material. Its contactless process can intrinsically avoid a failure mode of the tool sticking on the weld. The exact requirements for pipe alignment were assessed in comparison with the assembly tolerance. The groove geometry was modified to expand the allowable initial gap. The groove was machined to be partially thick to obviate the filler wire. First, plates with partially thick grooves were welded to elucidate the preferred groove geometry and welding conditions. With the modified groove, the plates were welded for the initial gap of 1.0 mm. Then the groove geometry and welding conditions were adjusted based on results of pipe welding tests. By application of the additional 0.5-mm-thick and 2.5-mm-wide metal in the groove, pipes with an initial gap of 0.7 mm were welded successfully.

Anatomy of a shoreface sand ridge revisted using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf

Science.gov (United States)

Robinson, Marci M.; McBride, Randolph A.

2008-01-01

Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf not, vert, ~5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

Determination of welding parameters for execution of weld overlayer on PWR nuclear reactor nozzles

International Nuclear Information System (INIS)

Ribeiro, Gabriela M.; Lima, Luciana I.; Quinan, Marco A.; Schvartzman, Monica M.

2009-01-01

In the PWR reactors, nickel based dissimilar welds have been presented susceptibilities the stress corrosion (S C). For the mitigation the problem a deposition of weld layers on the external surface of the nozzle is an alternative, viewing to provoke the compression of the region subjected to S C. This paper presents a preliminary study on the determination of welding parameters to obtain these welding overlayers. Welding depositions were performed on a test piece welded with nickel 182 alloy, simulating the conditions of a nozzle used in a PWR nuclear power plant. The welding process was the GTAW (Gas Tungsten Arc Welding), and a nickel 52 alloy as addition material. The overlayers were performed on the base metals, carbon steel an stainless steel, changing the welding parameters and verifying the the time of each weld filet. After that, the samples were micro structurally characterized. The macro structures and the microstructures obtained through optical microscopy and Vickers microhardness are presented. The preliminary results make evident the good weld quality. However, a small weld parameters influence used in the base material microstructure (carbon steel and stainless steel). The obtained results in this study will be used as reference in the construction of a mock up which will simulate all the conditions of a pressurizer nozzle of PWR reactor

Grinding Parts For Automatic Welding

Science.gov (United States)

Burley, Richard K.; Hoult, William S.

1989-01-01

Rollers guide grinding tool along prospective welding path. Skatelike fixture holds rotary grinder or file for machining large-diameter rings or ring segments in preparation for welding. Operator grasps handles to push rolling fixture along part. Rollers maintain precise dimensional relationship so grinding wheel cuts precise depth. Fixture-mounted grinder machines surface to quality sufficient for automatic welding; manual welding with attendant variations and distortion not necessary. Developed to enable automatic welding of parts, manual welding of which resulted in weld bead permeated with microscopic fissures.

Welding repair of a dissimilar weld and respective consequences for other German plants

International Nuclear Information System (INIS)

Brummer, G.; Dauwel, W.; Wesseling, U.; Ilg, U.; Lauer, P.; Widera, M.; Wachter, O.

2002-01-01

During a regular refueling outage in a German nuclear power plant in year 2000, additional non-destructive examinations have been performed on request of the Authority, to fulfill some recommendations of the independent experts with regard to the retrospective application of the Basic Safety Concept for the ferritic main coolant piping of this plant. During these inspections, indications were found in a dissimilar weld between one of the fifteen MCL (main coolant lines) nozzles and the ECC (emergency core cooling) system piping. By means of on-site metallography and laboratory investigations on three boat samples taken from this weld, it could be shown that the indications were due to hot cracking in the surface layer of the weld. In the course of these investigations, at three locations at the circumference of the weld, dis-bonding defects were found between the ferritic base metal of the nozzle and the austenitic weld butter, which has been applied to join the nozzle to the austenitic safe-end. According to the results of the extensive investigations, the dis-bonding occurred during the manufacturing process after stress-relief heat-treatment of the buttering during the welding of the austenitic safe-end to the butter material. There was no evidence for any crack growth during operation of the plant. Due to the large size of the boat-samples, a weld repair was mandatory. This repair has been performed using the so-called temper-bead technique as specified in the ASME Code, without subsequent stress relief heat treatment, using an advanced automatic orbital TIG welding process. The welding has been successfully performed without the need of further repair work. For those dissimilar welds, all other plants, except one, had used Inconel welding material for buttering the ferritic nozzle instead of stainless steel welding metal. For metallurgical reasons, dis-bonding along the fusion line for Inconel buttered dissimilar welds is unlikely to occur. Nevertheless all

EFFECTS OF ELECTRODE DEFORMATION OF RESISTANCE SPOT WELDING ON 304 AUSTENITIC STAINLESS STEEL WELD GEOMETRY

Directory of Open Access Journals (Sweden)

Nachimani Charde

2012-12-01

Full Text Available The resistance spot welding process is accomplished by forcing huge amounts of current flow from the upper electrode tip through the base metals to the lower electrode tip, or vice versa or in both directions. A weld joint is established between the metal sheets through fusion, resulting in a strong bond between the sheets without occupying additional space. The growth of the weld nugget (bond between sheets is therefore determined from the welding current density; sufficient time for current delivery; reasonable electrode pressing force; and the area provided for current delivery (electrode tip. The welding current and weld time control the root penetration, while the electrode pressing force and electrode tips successfully accomplish the connection during the welding process. Although the welding current and weld time cause the heat generation at the areas concerned (electrode tip area, the electrode tips’ diameter and electrode pressing forces also directly influence the welding process. In this research truncated-electrode deformation and mushrooming effects are observed, which result in the welded areas being inconsistent due to the expulsion. The copper to chromium ratio is varied from the tip to the end of the electrode whilst the welding process is repeated. The welding heat affects the electrode and the electrode itself influences the shape of the weld geometry.

Research on the Effects of Technical Parameters on the Molding of the Weld by A-TIG Welding

OpenAIRE

Shi, Kai; Pan, Wu

2012-01-01

The effects of welding parameters on the molding of weld by A-TIG welding of a 4mm thickness mild steel plate is studied in the present paper. The results obtained show that: as welding current increases A-TIG welding penetration gets deeper than TIG welding; size and shape of HAZ has remarkable change; A-TIG welding has the narrower weld pool width than TIG welding.

Electron beam welding

International Nuclear Information System (INIS)

Schwartz, M.M.

1974-01-01

Electron-beam equipment is considered along with fixed and mobile electron-beam guns, questions of weld environment, medium and nonvacuum welding, weld-joint designs, tooling, the economics of electron-beam job shops, aspects of safety, quality assurance, and repair. The application of the process in the case of individual materials is discussed, giving attention to aluminum, beryllium, copper, niobium, magnesium, molybdenum, tantalum, titanium, metal alloys, superalloys, and various types of steel. Mechanical-property test results are examined along with the areas of application of electron-beam welding

Recent developments in pipeline welding practice

Energy Technology Data Exchange (ETDEWEB)

1979-01-01

Fourteen chapters are included: overview of pipeline welding systems and quality assurance, CRC automatic welding system, H.C. Price Co. automatic welding system, semi-automatic MIG-welding process, partial penetration welding of steel pipes for gas distribution, construction procedures and quality control in offshore pipeline construction, welding in repair and maintenance of gas transmission pipelines, British Gas studies of welding on pressurized gas transmission pipelines, hot tapping pipelines, underwater welding for offshore pipelines and associated equipment, radial friction welding, material composition vs weld properties, review of NDT of pipeline welds, and safety assurance in pipeline construction. A bibliography of approximately 150 references is included, arranged according to subject and year.

X-ray radiography of Ti6Al4V welded by plasma tungsten arc (PTA) welding

Energy Technology Data Exchange (ETDEWEB)

Dikbas, Halil; Caligulu, Ugur; Taskin, Mustafa; Turkmen, Mustafa [Firat Univ., Elazig (Turkey). Metallurgy Dept.

2013-03-01

In this study, X-ray radiographic tests of Ti6Al4V alloys welded by plasma tungsten arc welding (PTA) were investigated. PTA welding experiments were carried out under argon shielding gas atmosphere, at 1400-1600 W and 1800 W welding powers as well as 1 m/min, 0.75 m/min, and 0.50 m/min welding speeds. After this process, radiography of the welded joints was performed by X-ray diffraction. The result of the radiographic tests indicated that by increasing welding power the widths of deep penetration increased in all specimens. On the contrary, increasing welding speeds decreases the widths deep penetration. The best properties of Ti6Al4V joints were observed for specimens welded at 1800 W welding power and at 0.50 m/min welding speed. (orig.)

Effects of welding parameters on friction stir spot welding of high density polyethylene sheets

International Nuclear Information System (INIS)

Bilici, Mustafa Kemal; Yukler, Ahmet Irfan

2012-01-01

Graphical abstract: (a) Schematic illustration of the cross section of a friction stir spot weld and (b) Geometry of the weld bonded area, x: nugget thickness and y: the thickness of the upper sheet. Highlights: → Welding parameters affect the FSSW nugget formation and the strength of the joint. → Melting of polyethylene occurred in the vicinity of the tool pin. → The joint that fractures with a pull nugget failure mode has a higher strength. -- Abstract: Friction stir spot welding parameters affect the weld strength of thermoplastics, such as high density polyethylene (HDPE) sheets. The effects of the welding parameters on static strength of friction stir spot welds of high density polyethylene sheets were investigated. For maximizing the weld strength, the selection of welding parameters is very important. In lap-shear tests two fracture modes were observed; cross nugget failure and pull nugget failure. The tool rotational speed, tool plunge depth and dwell time were determined to be important in the joint formation and its strength. The joint which had a better strength fails with a pull nugget failure morphology. Weld cross section image analysis of the joints were done with a video spectral comparator. The plunge rate of the tool was determined to have a negligible effect on friction stir spot welding.

Welding problems in nuclear power engineering

International Nuclear Information System (INIS)

Zubchenko, A.S.

1986-01-01

The problems of welding industry in nuclear power plant engineering, mainly related to the improvement of molten bath protection, are considered. Development of new materials for welding electrodes, for cladding and welding fluxes, is pointed out. Production of the following equipment is brought to a commercial level: welding heads and welding machines for branch pipe welding, anticorrosion cladding, zonal thermal treatment, electron beam welding facilities for the welding and maintenance of turbineblades, equipment for nondestructive testing of welded joints

Toughness of 2,25Cr-1Mo steel and weld metal

Science.gov (United States)

Acarer, Mustafa; Arici, Gökhan; Acar, Filiz Kumdali; Keskinkilic, Selcuk; Kabakci, Fikret

2017-09-01

2,25Cr-1Mo steel is extensively used at elevated temperature structural applications in fossil fire power plants for steam pipes, nozzle chambers and petrochemical industry for hydrocracking unit due to its excellent creep resistance and good redundant to oxidation. Also they should have acceptable weldability and toughness. The steels are supplied in quenched and tempered condition and their welded components are subjected to post-weld heat treatment (PWHT). Tempering process is carried out at 690-710°C to improve toughness properties. However they are sensitive to reheat cracking and temper embrittlement. To measure temper embrittlement of the steels and their weld metal, temper embrittlement factor and formula (J factor - Watanabe and X formula- Bruscato) are used. Step cooling heat treatment is also applied to determine temper embrittlement. In this study, toughness properties of Cr Mo (W) steels were reviewed. Also transition temperature curves of 2,25Cr-1Mo steel and its weld metal were constructed before and after step cool heat treatment as experimental study. While 2,25Cr-1Mo steel as base metal was supplied, all weld metal samples were produced in Gedik Welding Company. Hardness measurements and microstructure evaluation were also carried out.

Laser weld process monitoring and control using chromatic filtering of thermal radiation from a weld pool

International Nuclear Information System (INIS)

Kim, Cheol Jung; Kim, Min Suk; Baik, Sung Hoon; Chung, Chin Man

2000-06-01

The application of high power Nd: YAG lasers for precision welding in industry has been growing quite fast these days in diverse areas such as the automobile, the electronics and the aerospace industries. These diverse applications also require the new developments for the precise control and the reliable process monitoring. Due to the hostile environment in laser welding, a remote monitoring is required. The present development relates in general to weld process monitoring techniques, and more particularly to improved methods and apparatus for real-time monitoring of thermal radiation of a weld pool to monitor a size variation and a focus shift of the weld pool for weld process control, utilizing the chromatic aberration of focusing lens or lenses. The monitoring technique of the size variation and the focus shift of a weld pool is developed by using the chromatic filtering of the thermal radiation from a weld pool. The monitoring of weld pool size variation can also be used to monitor the weld depth in a laser welding. Furthermore, the monitoring of the size variation of a weld pool is independent of the focus shift of a weld pool and the monitoring of the focus shift of a weld pool is independent of the size variation of a weld pool

Laser weld process monitoring and control using chromatic filtering of thermal radiation from a weld pool

Energy Technology Data Exchange (ETDEWEB)

Kim, Cheol Jung; Kim, Min Suk; Baik, Sung Hoon; Chung, Chin Man

2000-06-01

The application of high power Nd: YAG lasers for precision welding in industry has been growing quite fast these days in diverse areas such as the automobile, the electronics and the aerospace industries. These diverse applications also require the new developments for the precise control and the reliable process monitoring. Due to the hostile environment in laser welding, a remote monitoring is required. The present development relates in general to weld process monitoring techniques, and more particularly to improved methods and apparatus for real-time monitoring of thermal radiation of a weld pool to monitor a size variation and a focus shift of the weld pool for weld process control, utilizing the chromatic aberration of focusing lens or lenses. The monitoring technique of the size variation and the focus shift of a weld pool is developed by using the chromatic filtering of the thermal radiation from a weld pool. The monitoring of weld pool size variation can also be used to monitor the weld depth in a laser welding. Furthermore, the monitoring of the size variation of a weld pool is independent of the focus shift of a weld pool and the monitoring of the focus shift of a weld pool is independent of the size variation of a weld pool.

Eastern Scheldt Sand, Baskarp Sand No. 15

DEFF Research Database (Denmark)

Andersen, A. T; Madsen, E. B.; Schaarup-Jensen, A. L.

The present data report contains data from 13 drained triaxial tests, performed on two different sand types in the Soil Mechanics Laboratory at Aalborg University in March, 1997. Two tests have been performed on Baskarp Sand No. 15, which has already ken extensively tested in the Soil Mechanics...... Laboratory. The remaining 11 triaxial tests have ben performed on Eastern Scheldt Sand, which is a material not yet investigated at the Soil Mechanics Laboratory. In the first pari of this data report, the characteristics of the two sand types in question will be presented. Next, a description...... will described. In this connection, the procedure for preparation of the soil specimens will be presented, and the actual performance of the tests will be briefly outlined. Finally, the procedure for processing of the measurements from the laboratory in order to obtain usable data will be described. The final...

Analysis of weld-cracking and improvement of the weld-repair process of superplastic forming tools

International Nuclear Information System (INIS)

Duchosal, A.; Deschaux-Beaume, F.; Lours, P.; Haro, S.; Fras, G.

2013-01-01

Highlights: ► Characterisation of the microstructure of a heat-resistant austenitic cast steel. ► Failure analysis using in situ tensile tests and isothermal fatigue tests. ► Analyses of weld cracking mechanism during shielded metal arc welding process. ► Improvement of weld-repair method by re-melting of the base material surface with GTAW process. - Abstract: Superplastic forming (SPF) dies are generally made of using heat resistant cast steels, which are very sensitive to weld cracking. In order to improve the weld-repair process of such dies to prevent weld-cracking, the microstructure and the mechanical behaviour of a typical heat-resistant cast steel was first studied, using isothermal low-cycle fatigue tests and in situ tensile tests. The welding behaviour of such steel was also investigated, using a shielded metal arc welding (SMAW) process and welding conditions similar to those employed for weld repair industrial dies. The comparison of the aspect of weld-cracking with the fracture mechanisms observed at room temperature or during isothermal low-cycle fatigue tests suggests a similar brittle failure mechanism, due to the presence of large interdendritic carbides in the cast steel. The melting of the cast steel surface using a gas tungsten arc welding (GTAW) process allowed to refine the primary carbides, and then to reduce the weld-cracking sensitivity. The refining method with GTAW before welding has been successfully tested to weld-repair a sample representative of SPF dies, and is recommended for subsequent repairs of such dies

Construction of large-thickness sand cushions for NPP foundations

International Nuclear Information System (INIS)

Krantsfel'd, Ya.L.; Losievskaya, I.K.; Kovalenko, R.P.; Mutalipov, A.

1982-01-01

A study is made on some technological peculiarities of preparation of NPP foundations and control methods of foundation density. As an example the experience of cement-sand foundation construction for two 900 MW power-units at the Koeberg South Africa NPP is briefly described. The experience of artificial foundation construction at this NPP indicates both the possibility of obtaining the required quality of cement-sand cushions and commercial construction of large volume of such cushions by acceptable rates and the necessity of unification of work quality characteristics

Real weld geometry determining mechanical properties of high power laser welded medium plates

Science.gov (United States)

Liu, Sang; Mi, Gaoyang; Yan, Fei; Wang, Chunming; Li, Peigen

2018-06-01

Weld width is commonly used as one of main factors to assess joint performances in laser welding. However, it changes significantly through the thickness direction in conditions of medium or thick plates. In this study, high-power autogenous laser welding was conducted on 7 mm thickness 201 stainless steel to elucidate the factor of whole weld transverse shape critically affecting the mechanical properties with the aim of predicting the performance visually through the weld appearance. The results show that single variation of welding parameters could result in great changes of weld pool figures and subsequently weld transverse shapes. All the obtained welds are composed of austenite containing small amount of cellular dendritic δ-Ferrite. The 0.2% proof stresses of Nail- and Peanut-shaped joint reach 458 MPa and 454 MPa, 88.2% and 87.5% of the base material respectively, while that of Wedge-shaped joint only comes to 371 MPa, 71.5% of the base material. The deterioration effect is believed to be caused by the axial grain zone in the weld center. The fatigue strength of joint P is a bit lower than N, but much better than W. Significant deformation incompatibility through the whole thickness and microstructure resistance to crack initiation should be responsible for the poor performance of W-shaped joints.

Tailoring weld geometry during keyhole mode laser welding using a genetic algorithm and a heat transfer model

International Nuclear Information System (INIS)

Rai, R; DebRoy, T

2006-01-01

Tailoring of weld attributes based on scientific principles remains an important goal in welding research. The current generation of unidirectional laser keyhole models cannot determine sets of welding variables that can lead to a particular weld attribute such as specific weld geometry. Here we show how a computational heat transfer model of keyhole mode laser welding can be restructured for systematic tailoring of weld attributes based on scientific principles. Furthermore, the model presented here can calculate multiple sets of laser welding variables, i.e. laser power, welding speed and beam defocus, with each set leading to the same weld pool geometry. Many sets of welding variables were obtained via a global search using a real number-based genetic algorithm, which was combined with a numerical heat transfer model of keyhole laser welding. The reliability of the numerical heat transfer calculations was significantly improved by optimizing values of the uncertain input parameters from a limited volume of experimental data. The computational procedure was applied to the keyhole mode laser welding of the 5182 Al-Mg alloy to calculate various sets of welding variables to achieve a specified weld geometry. The calculated welding parameter sets showed wide variations of the values of welding parameters, but each set resulted in a similar fusion zone geometry. The effectiveness of the computational procedure was examined by comparing the computed weld geometry for each set of welding parameters with the corresponding experimental geometry. The results provide hope that systematic tailoring of weld attributes via multiple pathways, each representing alternative welding parameter sets, is attainable based on scientific principles

Weld defect identification in friction stir welding using power spectral density

Science.gov (United States)

Das, Bipul; Pal, Sukhomay; Bag, Swarup

2018-04-01

Power spectral density estimates are powerful in extraction of useful information retained in signal. In the current research work classical periodogram and Welch periodogram algorithms are used for the estimation of power spectral density for vertical force signal and transverse force signal acquired during friction stir welding process. The estimated spectral densities reveal notable insight in identification of defects in friction stir welded samples. It was observed that higher spectral density against each process signals is a key indication in identifying the presence of possible internal defects in the welded samples. The developed methodology can offer preliminary information regarding presence of internal defects in friction stir welded samples can be best accepted as first level of safeguard in monitoring the friction stir welding process.

Residual stresses and their mechanisms of production at circumferential weld by heat-sink welding

International Nuclear Information System (INIS)

Ueda, Yukio; Nakacho, Keiji; Ohkubo, Katsumi; Shimizu, Tsubasa.

1983-01-01

In the previous report, the authors showed effectiveness of the heat-sink welding (water cooling) to accomplish this end by conducting theoretical analysis and an experiment on residual stresses in the 4B pipe of SUS 304 by the conventional welding and the heat-sink welding at a certain standard heat-input condition. In this research, different pipe sizes and varied heat-input are applied. The welding residual stresses by the conventional welding and the heat-sink welding are obtained by the theoretical analysis and their production mechanisms are clarified. Hence the influence of the above changes of conditions on effectiveness of the heat-sink welding is investigated. The main results are summarized as follow. (1) In case of this pipes such as 2B and 4B pipes, it is important to minimize heat-input per one pass (especially for latter half passes) in order to improve the effectiveness of the heat-sink welding. The effectiveness can be predicted either by theoretical analysis of the temperature distribution history with consideration of the characteristic of heat transfer under spray-watering or by experimental measurement. (2) In case of 24B pipes, thick pipes, it is desirable to minimize heat-input for the first half passes, by which the heat-sink welding becomes more effective. In addition, no matter whether the conventional welding or the heat-sink welding, it is important to prevent angular distorsion which produces tensile axial stresses on the inner surface of the pipe in the weld zone. Possible measures to meet these requirements are to apply restraining jigs, to minimize the section area of the groove (ex. application of the narrow gap arc welding), and to change continuous welding to skip one. (J.P.N.)

Instructional Guidelines. Welding.

Science.gov (United States)

Fordyce, H. L.; Doshier, Dale

Using the standards of the American Welding Society and the American Society of Mechanical Engineers, this welding instructional guidelines manual presents a course of study in accordance with the current practices in industry. Intended for use in welding programs now practiced within the Federal Prison System, the phases of the program are…

Welding process

International Nuclear Information System (INIS)

Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

2008-01-01

For the final chapter of this book, there is basic introduction on welding process. The good radiography must know somehow on welding process so that they can know what kind of welding that must rejected or not. All of the exposure technique that mention in earlier chapter almost applicable in this field because welding process is critical problem if there is no inspection will be done. So, for this chapter, all the discontinuity that usually appeared will be discussed and there is another discontinuity maybe not to important and do not give big impact if found it, do not described here. On top of that, the decision to accept or reject based on code, standard and specification that agreed by both to make sure that decision that agreed is corrected and more meaningful.

Welding quality evaluation of resistance spot welding using the time-varying inductive reactance signal

Science.gov (United States)

Zhang, Hongjie; Hou, Yanyan; Yang, Tao; Zhang, Qian; Zhao, Jian

2018-05-01

In the spot welding process, a high alternating current is applied, resulting in a time-varying electromagnetic field surrounding the welder. When measuring the welding voltage signal, the impedance of the measuring circuit consists of two parts: dynamic resistance relating to weld nugget nucleation event and inductive reactance caused by mutual inductance. The aim of this study is to develop a method to acquire the dynamic reactance signal and to discuss the possibility of using this signal to evaluate the weld quality. For this purpose, a series of experiments were carried out. The reactance signals under different welding conditions were compared and the results showed that the morphological feature of the reactance signal was closely related to the welding current and it was also significantly influenced by some abnormal welding conditions. Some features were extracted from the reactance signal and combined to construct weld nugget strength and diameter prediction models based on the radial basis function (RBF) neural network. In addition, several features were also used to monitor the expulsion in the welding process by using Fisher linear discriminant analysis. The results indicated that using the dynamic reactance signal to evaluate weld quality is possible and feasible.

Influence of weld discontinuities on strain controlled fatigue behavior of 308 stainless steel weld metal

International Nuclear Information System (INIS)

Bhanu Sankara Rao, K.; Valsan, M.; Sandhya, R.; Mannan, S.L.; Rodriguez, P.

1994-01-01

Detailed investigations have been performed for assessing the importance of weld discontinuities in strain controlled low cycle fatigue (LCF) behavior of 308 stainless steel (SS) welds. The LCF behavior of 308 SS welds containing defects was compared with that of type 304 SS base material and 308 SS sound weld metal. Weld pads were prepared by shielded metal arc welding process. Porosity and slag inclusions were introduced deliberately into the weld metal by grossly exaggerating the conditions normally causing such defects. Total axial strain controlled LCF tests have been conducted in air at 823 K on type 304 SS base and 308 SS sound weld metal employing strain amplitudes in the range from ±0.25 to ±0.8 percent. A single strain amplitude of ±0.25 percent was used for all the tests conducted on weld samples containing defects. The results indicated that the base material undergoes cyclic hardening whereas sound and defective welds experience cyclic softening. Base metal showed higher fatigue life than sound weld metal at all strain amplitudes. The presence of porosity and slag inclusions in the weld metal led to significant reduction in life. Porosity on the specimen surface has been found to be particularly harmful and caused a reduction in life by a factor of seven relative to sound weld metal

Development of resistance welding process. 6. Evaluation test of welding properties of martensitic ODS steel)

International Nuclear Information System (INIS)

Kono, Shusaku; Seki, Masayuki; Ishibashi, Fujio

2003-05-01

The welding condition and the heat-treatment condition were optimized to evaluate welding properties of the martensitic ODS steel cladding tube. The test pieces for evaluation of strength properties of the welded zone were produced by the optimized welding condition. In order to evaluate the strength of the welded zone, the internal creep rapture test, the single axis creep rapture test, the burst test and the tensile test were conducted. Following results were obtained in these tests. (1) Weld ability: An excellent welding characteristic was observed. The micro cracks, etc. were not served at the joint starting point. The joint starting points were connected uniformly with errors less than 0.05 mm. It is considered that an excellent welding characteristic was result of homogeneous micro structure of cladding material. (2) End plug material: In case of the material of end plug was martensitic ODS steel as same as that of cladding tube, the micro structure and the precipitation state carbide near the welded zone were found to be almost same as that of cladding tube. (3) Optimization of heat-treatment condition: The heat treatments of normalizing (1050degC) and tempering (780degC) were performed after welding and the micro structure near the welded zone was the isometric structure with low dislocation density, the precipitation state of carbide was uniform as same as that of cladding tube. These heat treatments can relax the residual stress accumulated when welding; it is considered that these heat treatments after welding are indispensable. (4) Strength of welded zone: The strength of the welded zone was found to be equal to that of cladding tube in all the strength tests. Therefore, it is concluded that the welding technology for the martensitic ODS steel is completed. (author)

Welding method by remote handling

International Nuclear Information System (INIS)

Hashinokuchi, Minoru.

1994-01-01

Water is charged into a pit (or a water reservoir) and an article to be welded is placed on a support in the pit by remote handling. A steel plate is disposed so as to cover the article to be welded by remote handling. The welding device is positioned to the portion to be welded and fixed in a state where the article to be welded is shielded from radiation by water and the steel plate. Water in the pit is drained till the portion to be welded is exposed to the atmosphere. Then, welding is conducted. After completion of the welding, water is charged again to the pit and the welding device and fixing jigs are decomposed in a state where the article to be welded is shielded again from radiation by water and the steel plate. Subsequently, the steel plate is removed by remote handling. Then, the article to be welded is returned from the pit to a temporary placing pool by remote handling. This can reduce operator's exposure. Further, since the amount of the shielding materials can be minimized, the amount of radioactive wastes can be decreased. (I.N.)

Weld pool boundary and weld bead shape reconstruction based on passive vision in P-GMAW

Institute of Scientific and Technical Information of China (English)

Yan Zhihong; Zhang Guangjun; Gao Hongming; Wu Lin

2006-01-01

A passive visual sensing system is established in this research, and clear weld pool images in pulsed gas metal arc welding ( P-GMA W) can be captured with this system. The three-dimensional weld pool geometry, especially the weld height,is not only a crucial factor in determining workpiece mechanical properties, but also an important parameter for reflecting the penetration. A new three-dimensional (3D) model is established to describe the weld pool geometry in P-GMAW. Then, a series of algorithms are developed to extract the model geometrical parameters from the weld pool images. Furthermore, the method to reconstruct the 3D shape of weld pool boundary and weld bead from the two-dimensional images is investigated.

Welding Course Curriculum.

Science.gov (United States)

Genits, Joseph C.

This guide is intended for use in helping students gain a fundamental background on the major aspects of the welding trade. The course emphasis is on mastery of the manipulative skills necessary to develop successful welding techniques and on acquisition of an understanding of the specialized tools and equipment used in welding. The first part…

Capacitor discharge process for welding braided cable

Science.gov (United States)

Wilson, Rick D.

1995-01-01

A capacitor discharge process for welding a braided cable formed from a plurality of individual cable strands to a solid metallic electrically conductive member comprises the steps of: (a) preparing the electrically conductive member for welding by bevelling one of its end portions while leaving an ignition projection extending outwardly from the apex of the bevel; (b) clamping the electrically conductive member in a cathode fixture; (c) connecting the electrically conductive member clamped in the cathode fixture to a capacitor bank capable of being charged to a preselected voltage value; (d) preparing the braided cable for welding by wrapping one of its end portions with a metallic sheet to form a retaining ring operable to maintain the individual strands of the braided cable in fixed position within the retaining ring; (e) clamping the braided cable and the retaining ring as a unit in an anode fixture so that the wrapped end portion of the braided cable faces the ignition projection of the electrically conductive member; and (f) moving the cathode fixture towards the anode fixture until the ignition projection of the electrically conductive member contacts the end portion of the braided cable thereby allowing the capacitor bank to discharge through the electrically conductive member and through the braided cable and causing the electrically conductive member to be welded to the braided cable via capacitor discharge action.

On post-weld heat treatment cracking in tig welded superalloy ATI 718Plus

Science.gov (United States)

Asala, G.; Ojo, O. A.

The susceptibility of heat affected zone (HAZ) to cracking in Tungsten Inert Gas (TIG) welded Allvac 718Plus superalloy during post-weld heat treatment (PWHT) was studied. Contrary to the previously reported case of low heat input electron beam welded Allvac 718Plus, where HAZ cracking occurred during PWHT, the TIG welded alloy is crack-free after PWHT, notwithstanding the presence of similar micro-constituents that caused cracking in the low input weld. Accordingly, the formation of brittle HAZ intergranular micro-constituents may not be a sufficient factor to determine cracking propensity, the extent of heat input during welding may be another major factor that influences HAZ cracking during PWHT of the aerospace superalloy Allvac 718Plus.

Recent changes in code requirements for repair of in-service pipelines by welding

Energy Technology Data Exchange (ETDEWEB)

Bruce, W.A. [Edison Welding Inst., Columbus, OH (United States)

2000-07-01

Corrosion damage on pipelines represents the second most important cause of damage to natural gas pipelines in the United States. The area containing the corrosion damage must be reinforced to prevent the pipeline to rupture and from bulging. The predominant method of reinforcing corrosion damage in cross-country pipelines is to install a full-encirclement repair sleeve. The recent up-date of American Petroleum Institute (API) code requirement for repair of in-service pipelines by welding was published to provide a recommended practice for pipeline maintenance welding. The recent changes to the code are explained. The appendix B to the up-date is intended to alleviate redundancy between API 1104 and API 1107 and the time lag between up-dates, and to address technological advances made in the area of in-service welding. An alternative repair method of deposited weld metal, or weld deposition repair is briefly explained. 9 refs., 5 figs.

Welding for the CRBRP steam generators

International Nuclear Information System (INIS)

Spalaris, C.N.; Ring, P.J.; Durand, R.E.; Wright, E.A.

1979-01-01

The rationale for selecting weld design, welding procedures and inspection methods was based upon the desire to obtain the highest reliability welds for the CRBRP steam generators. To assure the highest weld reliability, heavy emphasis was placed on the control of material cleanliness and composition substantially exceeding the requirements of the ASME Code for 2-1/4Cr--1Mo. The high tube/tubesheet weld quality was achieved through close material control, an extensive weld development program and the selection of high reliability welding equipment. Shell and nozzle weld fabrication using TIG, MIG, and submerged arc procedures are also being controlled through precise specifications, including preheat and postheat programs, together with radiography and ultrasonic inspection to ascertain the weld quality desired. Details of the tube/tubesheet welding and shell welding are described and results from the weld testing program are discussed

Performance of mesh seam welds in tailor welded blanks; Terado blank yo mash seam yosetsubu no tokusei

Energy Technology Data Exchange (ETDEWEB)

Uchihara, M; Takahashi, M; Kurita, M; Hirose, Y; Fukui, K [Sumitomo Metal Industries, Ltd., Osaka (Japan)

1997-10-01

Formability, fatigue properties and corrosion behavior of mash seam welded steel sheets were investigated and the results were compared with laser weld. The stretch formability of mash seam weld and laser weld were same level. Mash seam weld however, showed slightly smaller formability in hole expansion test. The fatigue strength of mash seam welds was lower than that of laser welds in case of differential thickness joints. Corrosion was apt to initiate at weld in both mash seam and laser weld with E-coat. The corrosion resistance of welds was improved by using zinc coated steel. 3 refs., 14 figs., 2 tabs.

Resistance Spot Welding of dissimilar Steels

Directory of Open Access Journals (Sweden)

Ladislav Kolařík

2012-01-01

Full Text Available This paper presents an analysis of the properties of resistance spot welds between low carbon steel and austenitic CrNi stainless steel. The thickness of the welded dissimilar materials was 2 mm. A DeltaSpot welding gun with a process tape was used for welding the dissimilar steels. Resistance spot welds were produced with various welding parameters (welding currents ranging from 7 to 8 kA. Light microscopy, microhardness measurements across the welded joints, and EDX analysis were used to evaluate the quality of the resistance spot welds. The results confirm the applicability of DeltaSpot welding for this combination of materials.

Using Taguchi method to optimize welding pool of dissimilar laser welded components

OpenAIRE

Anawa, E.; Olabi, Abdul-Ghani

2008-01-01

In the present work CO2 continuous laser welding process was successfully applied and optimized for joining a dissimilar AISI 316 stainless steel and AISI 1009 low carbon steel plates. Laser power, welding speed, and defocusing distance combinations were carefully selected with the objective of producing welded joint with complete penetration, minimum fusion zone size and acceptable welding profile. Fusion zone area and shape of dissimilar austenitic stainless steel with ferritic low carbon s...

Welding, Bonding and Fastening, 1984

Science.gov (United States)

Buckley, J. D. (Editor); Stein, B. A. (Editor)

1985-01-01

A compilation of papers presented in a joint NASA, American Society for Metals, The George Washington University, American Welding Soceity, and Society of Manufacturing Engineers conference on Welding, Bonding, and Fastening at Langley Research Center, Hampton, VA, on October 23 to 25, 1984 is given. Papers were presented on technology developed in current research programs relevant to welding, bonding, and fastening of structural materials required in fabricating structures and mechanical systems used in the aerospace, hydrospace, and automotive industries. Topics covered in the conference included equipment, hardware and materials used when welding, brazing, and soldering, mechanical fastening, explosive welding, use of unique selected joining techniques, adhesives bonding, and nondestructive evaluation. A concept of the factory of the future was presented, followed by advanced welding techniques, automated equipment for welding, welding in a cryogenic atmosphere, blind fastening, stress corrosion resistant fasteners, fastening equipment, explosive welding of different configurations and materials, solid-state bonding, electron beam welding, new adhesives, effects of cryogenics on adhesives, and new techniques and equipment for adhesive bonding.

Energy conservation in two wheeler head tube welding fixture by modeling

Science.gov (United States)

Kamalanathan, S.; Guruprasad, B.; Elango, A.

2018-05-01

Energy conservation in automotive industry plays a significant role to increase the productivity which reduces the Men, Material, and Machinery. The Automotive industry sector is one of the major sector which works in two or more times of loading of work pieces in welding fixture. It consumes more energy. This project focuses on reduce the energy consumption by applying single time loading of work pieces with minimum number of labours, machine and reduces scrap. Welding fixtures are designed for the components which are difficult to weld in normal way or without any holding unit. The fixture is to be designed for the two wheeler head tube assembly which is to be welded with its companion for its application. It is demonstrated by modelling in Uni-graphics Software and FEA analysis will be done by ANSYS and experimentally products are tested and execute in industry. A code of practice suggested establishing acceptable standard for energy used in Automotive industry.

Selected Welding Techniques, Part 2

National Research Council Canada - National Science Library

1964-01-01

Partial contents: CONVENTIONAL WELD JOINTS VERSUS BUTT JOINTS IN 1-INCH ALUMINUM PLATE, SPECIAL WELD JOINT PREPARATION, UPSET METAL EDGES FOR INCREASED WELD JOINT STRENGTH, OUT-OF-POSITION WELDING OF HEAVY GAGE...

Homogeneous weldings of copper

International Nuclear Information System (INIS)

Campurri, C.; Lopez, M.; Fernandez, R.; Osorio, V.

1995-01-01

This research explored the metallurgical and mechanical properties of arc welding of copper related with influence of Argon, Helium and mixtures of them. Copper plates of 6 mm thickness were welded with different mixtures of the mentioned gases. The radiography of welded specimens with 100% He and 100% Ar does not show show any porosity. On the other hand, the copper plates welded different gas mixtures presented uniform porosity in the welded zone. The metallographies show recrystallized grain in the heat affected zone, while the welding zone showed a dendritic structure. The results of the tensile strength vary between a maximum of 227 MPa for 100% He and a minimum of 174 MOa for the mixture of 60% He and 40% Ar. For the elongation after fracture the best values, about 36%, were obtained for pure gases. As a main conclusion, we can say that arc welding of copper is possible without loosing the mechanical and metallurgical properties of base metal. 6 refs

Optimization of process parameters in welding of dissimilar steels using robot TIG welding

Science.gov (United States)

Navaneeswar Reddy, G.; VenkataRamana, M.

2018-03-01

Robot TIG welding is a modern technique used for joining two work pieces with high precision. Design of Experiments is used to conduct experiments by varying weld parameters like current, wire feed and travelling speed. The welding parameters play important role in joining of dissimilar stainless steel SS 304L and SS430. In this work, influences of welding parameter on Robot TIG Welded specimens are investigated using Response Surface Methodology. The Micro Vickers hardness tests of the weldments are measured. The process parameters are optimized to maximize the hardness of the weldments.

Influence of shielding gas pressure on welding characteristics in CO2 laser-MIG hybrid welding process

Science.gov (United States)

Chen, Yanbin; Lei, Zhenglong; Li, Liqun; Wu, Lin

2006-01-01

The droplet transfer behavior and weld characteristics have been investigated under different pressures of shielding gas in CO2 laser and metal inert/active gas (laser-MIG) hybrid welding process. The experimental results indicate that the inherent droplet transfer frequency and stable welding range of conventional MIG arc are changed due to the interaction between CO2 laser beam and MIG arc in laser-MIG hybrid welding process, and the shielding gas pressure has a crucial effect on welding characteristics. When the pressure of shielding gas is low in comparison with MIG welding, the frequency of droplet transfer decreases, and the droplet transfer becomes unstable in laser-MIG hybrid welding. So the penetration depth decreases, which shows the characteristic of unstable hybrid welding. However, when the pressure of shielding gas increases to a critical value, the hybrid welding characteristic is changed from unstable hybrid welding to stable hybrid welding, and the frequency of droplet transfer and the penetration depth increase significantly.

Provenance and recycling of Arabian desert sand

Science.gov (United States)

Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid A.; Al-Juboury, Ali I. A.

2013-05-01

This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al

Welding technologies for nuclear machinery and equipment

International Nuclear Information System (INIS)

Kobayashi, Masahiro; Yokono, Tomomi.

1991-01-01

The main welding methods applied to nuclear machinery and equipment are shielded metal arc welding, submerged arc welding, MAG welding and TIG welding. But in the last 10 years, in order to improve the reliability required for the welding of nuclear machinery and equipment, the welding technologies aiming at the reduction of heat input, the decrease of the number of welding pass and the automatic control of welding factors have been applied for the main purpose of bettering the quality and excluding human errors. The merits and the technology of narrow gap, pulsed MAG welding and melt-through welding are explained. As the automation of TIG welding, image processing type narrow gap, hot wire TIG welding and remote control type automatic TIG welding are described. For the longitudinal welding of active metal sheet products, plasma key-hole welding is applied. Since the concentration of its arc is good, high speed welding with low heat input can be done. For the stainless steel cladding by welding, electroslag welding has become to be employed in place of conventional submerged arc welding. Arc is not generated in the electroslag welding, and the penetration into base metal is small. (K.I.)

Tensile Test of Welding Joint Parts for a Plate-type Fuel Assembly

Energy Technology Data Exchange (ETDEWEB)

Yoon, K. H.; Kim, J. Y.; Kim, H. J.; Yim, J. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-05-15

The tensile tests were performed using an INSTRON 4505 (universal tensile) testing machine. These welding joints are composed of two parts for the soundness of the fuel assembly; one is the side plate with a fixing bar and the other is a side plate with an end fitting. These two joint parts are fabricated by TIG welding method. The tensile tests of the welding joints of a plate-type FA are executed by a tensile test. The fixture configurations for the specimen are very important to obtain the strict test results. The maximum strength has an approximately linear correlation with the unit bonding length of the welding joints. In spite of these results, the maximum strengths of the welding joints are satisfied according to the minimum requirement. These tensile tests of the joint parts for a plate-type fuel assembly (FA) have to be executed to evaluate the structural strength. For the tensile test, the joint parts of a FA used in the test are made of aluminum alloy (Al6061-T6)

Tensile Test of Welding Joint Parts for a Plate-type Fuel Assembly

International Nuclear Information System (INIS)

Yoon, K. H.; Kim, J. Y.; Kim, H. J.; Yim, J. S.

2013-01-01

The tensile tests were performed using an INSTRON 4505 (universal tensile) testing machine. These welding joints are composed of two parts for the soundness of the fuel assembly; one is the side plate with a fixing bar and the other is a side plate with an end fitting. These two joint parts are fabricated by TIG welding method. The tensile tests of the welding joints of a plate-type FA are executed by a tensile test. The fixture configurations for the specimen are very important to obtain the strict test results. The maximum strength has an approximately linear correlation with the unit bonding length of the welding joints. In spite of these results, the maximum strengths of the welding joints are satisfied according to the minimum requirement. These tensile tests of the joint parts for a plate-type fuel assembly (FA) have to be executed to evaluate the structural strength. For the tensile test, the joint parts of a FA used in the test are made of aluminum alloy (Al6061-T6)

Western Gas Sands Project: stratigrapy of the Piceance Basin

Energy Technology Data Exchange (ETDEWEB)

Anderson, S. (comp.)

1980-08-01

The Western Gas Sands Project Core Program was initiated by US DOE to investigate various low permeability, gas bearing sandstones. Research to gain a better geological understanding of these sandstones and improve evaluation and stimulation techniques is being conducted. Tight gas sands are located in several mid-continent and western basins. This report deals with the Piceance Basin in northwestern Colorado. This discussion is an attempt to provide a general overview of the Piceance Basin stratigraphy and to be a useful reference of stratigraphic units and accompanying descriptions.

Ultrasonic inspection of austenitic welds

International Nuclear Information System (INIS)

Baikie, B.L.; Wagg, A.R.; Whittle, M.J.; Yapp, D.

1976-01-01

The ultrasonic examination of austenitic stainless steel weld metal has always been regarded as a difficult proposition because of the large and variable ultrasonic attenuations and back scattering obtained from apparently similar weld deposits. The work to be described shows how the existence of a fibre texture within each weld deposit (as a result of epitaxial growth through successive weld beads) produces a systematic variation in the ultrasonic attenuation coefficient and the velocity of sound, depending upon the angle between the ultrasonic beam and the fibre axis. Development work has shown that it is possible to adjust the welding parameters to ensure that the crystallographic texture within each weld is compatible with improved ultrasonic transmission. The application of the results to the inspection of a specific weld in type 316 weld metal is described

Electron beam welding of aluminium components

International Nuclear Information System (INIS)

Maajid, Ali; Vadali, S.K.; Maury, D.K.

2015-01-01

Aluminium is one of the most widely used materials in industries like transportation, shipbuilding, manufacturing, aerospace, nuclear, etc. The challenges in joining of aluminium are distortion, cleanliness and quality. Main difficulties faced during fusion welding of aluminium components are removal of surface oxide layer, weld porosity, high heat input requirement, distortion, hot cracking, etc. Physical properties of aluminium such as its high thermal conductivity, high coefficient of thermal expansion, no change in colour at high temperature, large difference in the melting points of the metal and its oxide (∼ 1400 °C) compound the difficulties faced during welding. Gas Tungsten Arc Welding (GTAW), Gas Metal Arc Welding (GMAW), Plasma Arc Welding (PAW), etc are generally used in industries for fusion welding of aluminium alloys. However in case of thicker jobs the above processes are not suitable due to requirements of elaborate edge preparation, preheating of jobs, fixturing to prevent distortion, etc. Moreover, precise control over the heat input during welding and weld bead penetration is not possible with above processes. Further, if heat sensitive parts are located near the weld joint then high energy density beam welding process like Electron Beam Welding (EBW) is the best possible choice for aluminium welding.This paper discusses EB welding of aluminium components, typical geometry of components, selection/optimization of welding parameters, problems faced during standardization of welding and process parameters and their remedies etc.

Characterization of napthenic acids in oil sands process-affected waters using fluorescence technology

International Nuclear Information System (INIS)

Brown, L.; Alostaz, M.; Ulrich, A.

2009-01-01

Process-affected water from oil sands production plants presents a major environmental challenge to oil sands operators due to its toxicity to different organisms as well as its corrosiveness in refinery units. This abstract investigated the use of fluorescence excitation-emission matrices to detect and characterize changes in naphthenic acid in oil sands process-affected waters. Samples from oil sands production plants and storage ponds were tested. The study showed that oil sands naphthenic acids show characteristic fluorescence signatures when excited by ultraviolet light in the range of 260 to 350 mm. The signal was a unique attribute of the naphthenic acid molecule. Changes in the fluorescence signature can be used to determine chemical changes such as degradation or aging. It was concluded that the technology can be used as a non-invasive continuous water quality monitoring tool to increase process control in oil sands processing plants

Waste canister closure welding using the inertia friction welding process

International Nuclear Information System (INIS)

Klein, R.F.; Siemens, D.H.; Kuruzar, D.L.

1986-02-01

Liquid radioactive waste presently stored in underground tanks is to undergo a vitrifying process which will immobilize it in a solid form. This solid waste will be contained in a stainless steel canister. The canister opening requires a positive seal weld, the properties and thickness of which are at least equal to those of the canister material. This paper describes the inertia friction welding process and a proposed equipment design concept that will provide a positive, reliable, inspectable, and full thickness seal weld while providing easily maintainable equipment, even though the weld is made in a highly contaminated hot cell. All studies and tests performed have shown the concept to be highly feasible. 2 refs., 6 figs

Spot weld arrangement effects on the fatigue behavior of multi-spot welded joints

International Nuclear Information System (INIS)

Hassanifard, Soran; Zehsaz, Mohammad; Esmaeili, Firooz

2011-01-01

In the present study, the effects of spot weld arrangements in multi-spot welded joints on the fatigue behavior of the joints are studied. Three different four-spot welded joints are considered: one-row four-spot parallel to the loading direction, one-row four-spot perpendicular to the loading direction and two-row four-spot weld specimens. The experimental fatigue test results reveal that the differences between the fatigue lives of three spot welded types in the low cycle regime are more considerable than those in the high cycle regime. However, all kinds of spot weld specimens have similar fatigue strength when approaching a million cycles. A non-linear finite element analysis is performed to obtain the relative stress gradients, effective distances and notch strength reduction factors based on the volumetric approach. The work here shows that the volumetric approach does a very good job in predicting the fatigue life of the multi-spot welded joints

Investigate The Effect Of Welding Parameters On Mechanical Properties During The Welding Of Al-6061 Alloy

Directory of Open Access Journals (Sweden)

Rajendra Prasad

2017-10-01

Full Text Available Friction welding is a solid state welding technique which is being used in recent times to weld similar as well as dissimilar metals for getting defect free weld. Many combinations like low carbon to stainless steel austenitic to ferrite stainless steel aluminium to copper and titanium to aluminium or steel have been tried out by various solid state welding processes with quite good results. In the present work the 3 level full factorial design has been employed to investigate the effect of welding parameters on tensile strength toughness and heat generation during the welding of Al-6061 alloy. Mathematical relationships between friction welding parameters and mechanical properties like heat generation tensile strength and toughness have also been developed. An attempt has also been made to examine the fracture surfaces of test specimens using SEM. It has been found that welding speed is the most significant parameter thats affect the heat generation tensile strength and toughness. it has been found that tensile strength and toughness during welding increases with increased in welding speed while tensile strength and toughness initially increased as the welding time increases after that it decreased with increase in welding time. The difference in weight of alloying elements can be clearly seen by analyzing spectrum of elements.

Mechanical and electrochemical characteristics with welding materials in robotic MIG welding of dissimilar Al alloys

Energy Technology Data Exchange (ETDEWEB)

Kim, Seong Jong; Han, Min Su; Woo, Yong Bin [Mokpo Maritime Univ., Mokpo (Korea, Republic of)

2013-05-15

In this study, mechanical and electrochemical characteristics with welding material in MIG welded with ROBOT for dissimilar Al alloys were investigated using various experiment methods. The MIG welding by ROBOT with ER5183 and ER5556 for the 5456-H116 and 6061-T6 Al alloy were carried out. The hardness of welding zone was lower than that of base metal. In electrochemical experiment, ER5183 welding material presented excellent characteristics. The yield strength and maximum tensile strength in welding with welding material of ER5183 presented lower value than those of ER5556. The elongation and time-to-fracture showed the opposite results.

Microstructure and toughness of ferritic weld metal of hyperbaric welded joints

International Nuclear Information System (INIS)

Mueller, L.

1988-01-01

In the present work ferritic weld metals of hyperbaric MIG/MAG welds with pressures up to 100 bar were examined. As a result of the pressure, interactions with the shielding gas, the filler metal as well as with the welding parameters had to be expected and were consequently included in the analysis. Investigation was focused on the influence of these parameters on the chemical composition of the weld metals, the microstructure and toughness behaviour, including fracture mechanics test. Using quantitative microstructural analysis as well as fractography a correlation between microstructure and toughness has been shown. (orig.) [de

Structural integrity and fatigue crack propagation life assessment of welded and weld-repaired structures

Science.gov (United States)

Alam, Mohammad Shah

2005-11-01

Structural integrity is the science and technology of the margin between safety and disaster. Proper evaluation of the structural integrity and fatigue life of any structure (aircraft, ship, railways, bridges, gas and oil transmission pipelines, etc.) is important to ensure the public safety, environmental protection, and economical consideration. Catastrophic failure of any structure can be avoided if structural integrity is assessed and necessary precaution is taken appropriately. Structural integrity includes tasks in many areas, such as structural analysis, failure analysis, nondestructive testing, corrosion, fatigue and creep analysis, metallurgy and materials, fracture mechanics, fatigue life assessment, welding metallurgy, development of repairing technologies, structural monitoring and instrumentation etc. In this research fatigue life assessment of welded and weld-repaired joints is studied both in numerically and experimentally. A new approach for the simulation of fatigue crack growth in two elastic materials has been developed and specifically, the concept has been applied to butt-welded joint in a straight plate and in tubular joints. In the proposed method, the formation of new surface is represented by an interface element based on the interface potential energy. This method overcomes the limitation of crack growth at an artificial rate of one element length per cycle. In this method the crack propagates only when the applied load reaches the critical bonding strength. The predicted results compares well with experimental results. The Gas Metal Arc welding processes has been simulated to predict post-weld distortion, residual stresses and development of restraining forces in a butt-welded joint. The effect of welding defects and bi-axial interaction of a circular porosity and a solidification crack on fatigue crack propagation life of butt-welded joints has also been investigated. After a weld has been repaired, the specimen was tested in a universal

Automatic Welding Control Using a State Variable Model.

Science.gov (United States)

1979-06-01

A-A10 610 NAVEAL POSTGRADUATE SCH4O.M CEAY CA0/ 13/ SAUTOMATIC WELDING CONTROL USING A STATE VARIABLE MODEL.W()JUN 79 W V "my UNCLASSIFIED...taverse Drive Unit // Jbint Path /Fixed Track 34 (servomotor positioning). Additional controls of heave (vertical), roll (angular rotation about the

Analysis of the Corrosion Behavior of an A-TIG Welded SS 409 Weld Fusion Zone

Science.gov (United States)

Vidyarthy, R. S.; Dwivedi, D. K.

2017-11-01

AISI 409 (SS 409) ferritic stainless steel is generally used as the thick gauge section in freight train wagons, in ocean containers, and in sugar refinery equipment. Activating the flux tungsten inert gas (A-TIG) welding process can reduce the welding cost during fabrication of thick sections. However, corrosion behavior of the A-TIG weld fusion zone is a prime concern for this type of steel. In the present work, the effect of the A-TIG welding process parameters on the corrosion behavior of a weld fusion zone made of 8-mm-thick AISI 409 ferritic stainless-steel plate has been analyzed. Potentiodynamic polarization tests were performed to evaluate the corrosion behavior. The maximum corrosion potential ( E corr) was shown by the weld made using a welding current of 215 A, a welding speed of 95 mm/min, and a flux coating density of 0.81 mg/cm2. The minimum E corr was observed in the weld made using a welding current of 190 A, a welding speed of 120 mm/min, and a flux coating density of 1.40 mg/cm2. The current study also presents the inclusive microstructure-corrosion property relationships using the collective techniques of scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction.

Microstructures and electrochemical behaviors of the friction stir welding dissimilar weld.

Science.gov (United States)

Shen, Changbin; Zhang, Jiayan; Ge, Jiping

2011-06-01

By using optical microscope, the microstructures of 5083/6082 friction stir welding (FSW) weld and parent materials were analyzed. Meanwhile, at ambient temperature and in 0.2 mol/L NaHS03 and 0.6 mol/L NaCl solutionby gravimetric test, potentiodynamic polarization curve test, electrochemical impedance spectra (EIS) and scanning electron microscope (SEM) observation, the electrochemical behavior of 5083/6082 friction stir welding weld and parent materials were comparatively investigated by gravimetric test, potentiodynamic polarization curve test, electrochemical impedance spectra (EIS) and scanning electron microscope (SEM) observation. The results indicated that at given processing parameters, the anti-corrosion property of the dissimilar weld was superior to those of the 5083 and 6082 parent materials. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Properties of welded joints in laser welding of aeronautic aluminum-lithium alloys

Science.gov (United States)

Malikov, A. G.; Orishich, A. M.

2017-01-01

The work presents the experimental investigation of the laser welding of the aluminum-lithium alloys (system Al-Mg-Li) and aluminum alloy (system Al-Cu-Li) doped with Sc. The influence of the nano-structuring of the surface layer welded joint by the cold plastic deformation method on the strength properties of the welded joint is determined. It is founded that, regarding the deformation degree over the thickness, the varying value of the welded joint strength is different for these aluminum alloys.

Tailor-welded blanks and their production

Science.gov (United States)

Yan, Qi

2005-01-01

Tailor welded blanks had been widely used in the automobile industry. A tailor welded blank consists of several flat sheets that were laser welded together before stamping. A combination of different materials, thickness, and coatings could be welded together to form a blank for stamping car body panels. As for the material for automobile industry, this technology was one of the development trend for automobile industry because of its weight reduction, safety improvement and economical use of materials. In this paper, the characters and production of tailor welded blanks in the market were discussed in detail. There had two major methods to produce tailor welded blanks. Laser welding would replace mesh seam welding for the production of tailor welded blanks in the future. The requirements on the edge preparation of unwelded blanks for tailor welded blanks were higher than the other steel processing technology. In order to produce the laser welded blank, there had the other process before the laser welding in the factory. In the world, there had three kinds of patterns for the large volume production of tailor welded blanks. In China, steel factory played the important role in the promotion of the application of tailor welded blanks. The competition for the supply of tailor welded blanks to the automobile industry would become fierce in the near future. As a result, the demand for the quality control on the production of tailor welded blanks would be the first priority concern for the factory.

Submarine sand ridges and sand waves in the eastern part of the China Sea

Science.gov (United States)

Wu, Ziyin; Li, Shoujun; Shang, Jihong; Zhou, Jieqiong; Zhao, Dineng; Liang, Yuyang

2016-04-01

Integrated with multi-beam and single-beam echo sounding data, as well as historical bathymetric data, submarine bathymetric maps of the eastern part of the China Sea, including the Bohai Sea, Huanghai Sea, and East China Sea, are constructed to systematically study submarine sand ridges and sand waves in the eastern part of the China Sea, combined with high-resolution seismic, sub-bottom profile and borehole data. Submarine sand ridges are extraordinarily developed in the eastern part of the China Sea, and 7 sand ridge areas can be divided from north to south, that is, the Laotieshan Channel sand ridge area in the Bohai Sea, the Korea Bay sand ridge area in the southern Huanghai Sea, the sand ridge area in the eastern Huanghai islands and the Huanghai Troughs, the Jianggang sand ridge area in the western Huanghai Sea, the sand ridge area in the East China Sea shelf, and the sand ridge and sand wave area in the Taiwan Strait and Taiwan Banks. The distribution area of the sand ridges and sand waves covers more than 450,000 km2, wherein ~10,000 km2 in the Bohai Bay, ~200,000 km2 in the Huanghai Sea, ~200,000 km2 in the East China Sea shelf, and ~40,000 km2 in the Taiwan Strait and Taiwan Banks, respectively. The great mass of sand ridges are distributed within water depth of 5-160 m, with a total length of over 160 km and a main width of 5-10 km. The inner structure of the sand ridges presents features of high-angle inclined beddings, with main lithology of sands, sand-mud alternations partly visible, and a small number of mud cores. Dating results indicate that the sand ridges in the eastern part of the China Sea are mainly developed in the Holocene. Sea-level variation dominates the sand ridge evolution in the eastern part of the China Sea since the LGM, and the sand ridges developed in the area of < 60m water depth are appeared in bad activity, meanwhile sand ridges with good activity are still developed in large scale.

The Effect of Welding Energy on the Microstructural and Mechanical Properties of Ultrasonic-Welded Copper Joints

Science.gov (United States)

Yang, Jingwei; Cao, Biao; Lu, Qinghua

2017-01-01

The effects of welding energy on the mechanical and microstructural characteristics of ultrasonic-welded pure copper plates were investigated. Complex dynamic recrystallization and grain growth occurred inside the weld zone during ultrasonic welding. At a low welding energy, a thin band of straight weld interfaces was observed and had an ultra-fine grain structure. With an increase in welding energy, the weld interface progressively changed from flat to sinusoidal, and eventually turned into a convoluted wavy pattern, bearing similarities to shear instabilities, as observed in fluid dynamics. The lap shear load of the joints initially increased and then remained stable as the welding energy increased. The tensile characteristics of the joints significantly depended on the development of plastic deformation at the interface. The influence of the microstructure on the hardness was also discussed. PMID:28772553

Influence of the welding temperature and the welding speed on the mechanical properties of friction stir welds in EN AW-2219-T87

Science.gov (United States)

Bachmann, A.; Krutzlinger, M.; Zaeh, M. F.

2018-06-01

Friction Stir Welding (FSW) is an innovative joining technique, which has proven to produce high quality joints in high strength aluminum alloys. Consequently, it is commonly used to manufacture lightweight aerospace structures with stringent requirements. For these structures, it is necessary to ensure a high ultimate tensile strength (UTS). Various studies have reported that the UTS is significantly influenced by the welding parameters. Samples welded with different parameter sets showed a considerably different UTS, despite being free from detectable welding defects (e.g. tunnel defect, voids, or lack of penetration). Based on the observations in the literature, a hypothesis was posed. The welding temperature along with the welding speed determine the UTS of the weld. This study aims to prove this hypothesis experimentally by using temperature-controlled FSW to join plates of EN AW-2219-T87 in butt joint configuration. The welded samples were examined using visual inspection, metallography, X-ray imaging, and uniaxial tensile tests. Finally, a statistical analysis was conducted. Hereby, the hypothesis was confirmed.

Plasma Processes of Cutting and Welding

Science.gov (United States)

1976-02-01

TIG process. 2.2.2 Keyhole Welding In plasma arc welding , the term...Cutting 3 3 4 4 4 2.2 Plasma Arc Welding 5 2.2.1 Needle Arc Welding 2.2.2 Keyhole Welding 5 6 3. Applications 8 93.1 Economics 4. Environmental Aspects of...Arc Lengths III. Needle Arc Welding Conditions IV. Keyhole Welding Conditions v. Chemical Analyses of Plates Used - vii - 1. 2. 3. 4. 5. 6. 7. 8.

10,170 flawless welds

CERN Multimedia

Antonella Del Rosso

2014-01-01

The welding of tubes containing the principal current-carrying busbars in the LHC magnets was one of the main activities of the SMACC project. After a year of preparation and another of intense activity in the tunnel, the last weld was completed on Wednesday 14 May. Over 10,170 welds have been inspected and not a single fault has been found.    The welder (above) creates the weld using an orbital welding machine (below) specifically designed for CERN. Each of the eight sectors of the LHC contains around 210 interconnects between the superconducting magnets. Consolidating these interconnections was the SMACC project’s primary objective. One of the last jobs before closing the interconnects is the welding of the M lines: each has a 104 mm diameter and a radial clearance of just 45 mm. In total: 10,170 welds carried out in a single year of activities. A true challenge, which was carried out by a team of 30 highly specialised welders, working under the supervision o...

Equipment for welding of details and joints of plastic pipes in work shop conditions and at pipelines

International Nuclear Information System (INIS)

Doronin, V.A.

1988-01-01

A range of welding machines for operation in workshop conditions and at pipelines is presented. Set of welding equipment for mobile shop, producing prototypes, and mobile facility are developed. In 1989 they will provide the whole operation cycle of production and mounting of details and units of plastic tubes and will enable to organize the centralized production of welded and shaped details in the branch, thus excluding the shortage of these details. 8 refs.; 6 figs.; 2 tabs

Effects of Flux Precoating and Process Parameter on Welding Performance of Inconel 718 Alloy TIG Welds

Science.gov (United States)

Lin, Hsuan-Liang; Wu, Tong-Min; Cheng, Ching-Min

2014-01-01

The purpose of this study is to investigate the effect of activating flux on the depth-to-width ratio (DWR) and hot cracking susceptibility of Inconel 718 alloy tungsten inert gas (TIG) welds. The Taguchi method is employed to investigate the welding parameters that affect the DWR of weld bead and to achieve optimal conditions in the TIG welds that are coated with activating flux in TIG (A-TIG) process. There are eight single-component fluxes used in the initial experiment to evaluate the penetration capability of A-TIG welds. The experimental results show that the Inconel 718 alloy welds precoated with 50% SiO2 and 50% MoO3 flux were provided with better welding performance such as DWR and hot cracking susceptibility. The experimental procedure of TIG welding process using mixed-component flux and optimal conditions not only produces a significant increase in DWR of weld bead, but also decreases the hot cracking susceptibility of Inconel 718 alloy welds.

Effect of rotation speed and welding speed on Friction Stir Welding of AA1100 Aluminium alloy

Science.gov (United States)

Raja, P.; Bojanampati, S.; Karthikeyan, R.; Ganithi, R.

2018-04-01

Aluminum AA1100 is the most widely used grade of Aluminium due to its excellent corrosion resistance, high ductility and reflective finish, the selected material was welded with Friction Stir Welding (FSW) process on a CNC machine, using a combination of different tool rotation speed (1500 rpm, 2500 rpm, 3500 rpm) and welding speed (10 mm/min, 30 mm/min, 50 mm/min) as welding parameters. The effect of FSW using this welding parameter was studied by measuring the ultimate tensile strength of the welded joints. A high-speed steel tool was prepared for welding the Aluminium AA1100 alloy having an 8mm shoulder diameter and pin dimension of 4mm diameter and 2.8 mm length. The welded joints were tested using the universal testing machine. It was found that Ultimate Tensile Strength of FSW specimen was highest with a value of 98.08 MPa when the weld was performed at rotation speed of 1500 RPM and welding speed of 50 mm/min.

New process for weld metal reliability

International Nuclear Information System (INIS)

Hebel, A.G.

1985-01-01

The industry-wide nature of weld cracking alerts one to the possibility that there is a fundamental law being overlooked. And in overlooking this law, industry is unable to counteract it. That law mandates that restraint during welding causes internal stress; internal stress causes weld metal to crack. Component restraint during welding, according to the welding standard, is the major cause of weld metal failures. When the metal working industry accepts this fact and begins to counter the effects of restraint, the number of weld failures experienced fall dramatically. Bonal Technologies, inc., of Detroit, has developed the first consistently effective non-thermal process to relieve stress caused by restraint during welding. Bonal's patented Mets-Lax sub-resonant stress relief acts as a restraint neutralizer when used during welding. Meta-Lax weld conditioning produces a finer more uniform weld grain structure. A finer, more uniform grain structure is a clear metallurgical indication of improved mechanical weld properties. Other benefits like less internal stress, and less warpage are also achieved

Effects of alloying element on weld characterization of laser-arc hybrid welding of pure copper

Science.gov (United States)

Hao, Kangda; Gong, Mengcheng; Xie, Yong; Gao, Ming; Zeng, Xiaoyan

2018-06-01

Effects of alloying elements of Si and Sn on weld characterizations of laser-arc hybrid welded pure copper (Cu) with thickness of 2 mm was studied in detail by using different wires. The weld microstructure was analyzed, and the mechanical properties (micro-hardness and tensile property), conductivity and corrosion resistance were tested. The results showed that the alloying elements benefit the growth of column grains within weld fusion zone (FZ), increase the ultimate tensile strength (UTS) of the FZ and weld corrosion resistance, and decrease weld conductivity. The mechanisms were discussed according to the results.

Nondestructive testing: welding industry

International Nuclear Information System (INIS)

Raj, Baldev; Subramanian, C.V.

1992-01-01

This chapter highlights various conventional and advanced nondestructive testing (NDT) techniques that have been used for weld evaluation. Welding Codes and Standards of International and National organisations that have been followed in India for various weld evaluation purposes are also included. The chapter also emphasises the importance of NDT by way of a few case studies that have been carried out on important critical welded components. (author). 12 refs., 17 figs., 1 appendix

Finite element simulation of the welding process and structural behaviour of welded components

International Nuclear Information System (INIS)

Locci, J.M.; Rouvray, A. de; Barbe, B.; Poirier, J.

1977-01-01

In the field of inelastic analysis of nuclear metal structures, the computation of residual stresses in welds, and their effects on the strength of welded components is of major importance. This paper presents an experimentally checked finite element simulation with the general nonlinear program PAM NEP-D, of the electron beam welding of two thick hemispherical shells, and the behaviour of the welded sphere under various additional thermomechanical sollicitations. (Auth.)

Corrosion Behavior of Arc Weld and Friction Stir Weld in Al 6061-T6 Alloys

International Nuclear Information System (INIS)

Yoon, Byoung Hyun; Kim, Heung Ju; Chang, Woong Seong; Kweon, Young Gak

2006-01-01

For the evaluation of corrosion resistance of Al 6061-T6 Alloy, Tafel method and immersion test was performed with Friction Stir Weld(FSW) and Gas Metal Arc Weld(GMAW). The Tafel and immersion test results indicated that GMA weld was severely attacked compared with those of friction stir weld. It may be mainly due to the galvanic corrosion mechanism act on the GMA weld

Metallurgical and fatigue assessments of welds in cast welded hydraulic turbine runners

International Nuclear Information System (INIS)

Trudel, A; Sabourin, M

2014-01-01

Decades of hydraulic turbine operation around the world have shown one undeniable fact; welded turbine runners can be prone to fatigue cracking, especially in the vicinity of welds. In this regard, three factors are essential to consider in runner fatigue assessments: (1) the runner's design, which can induce stress concentrations in the fillets, (2) the casting process, which inherently creates defects such as shrinkage cavities and (3) the welding process, which induces significant residual stresses as well as a heat affected zone in the cast pieces near the interface with the filler metal. This study focuses on the latter, the welding process, with emphasis on the influence of the heat affected zone on the runner's fatigue behavior. In a recently concluded study by a large research consortium in Montreal, the microstructure and fatigue crack propagation properties of a CA6NM runner weld heat affected zone were thoroughly investigated to find if this zone deteriorates the runner's resistance to fatigue cracking. The main results showed that this zone's intrinsic fatigue crack propagation resistance is only slightly lower than the unaffected base metal because of its somewhat finer martensitic microstructure leading to a less tortuous crack path. However, it was also confirmed that weld-induced residual stresses represent the dominant influencing factor regarding fatigue crack propagation, though post-weld heat treatments are usually very effective in reducing such residual stresses. This paper aims to further confirm, through a case study, that the weld-induced heat affected zone does not compromise the reliability of welded turbine runners when its fatigue crack propagation properties are considered in fatigue damage models

Numerical evaluation of multipass welding temperature field in API 5L X80 steel welded joints

Directory of Open Access Journals (Sweden)

J Nóbrega

2016-10-01

Full Text Available Many are the metallurgical changes suffered by materials when subjected to welding thermal cycle, promoting a considerable influence on the welded structures thermo mechanical properties. In project phase, one alternative for evaluating the welding cycle variable, would be the employment of computational methods through simulation. So, this paper presents an evaluation of the temperature field in a multipass welding of API 5L X80 steel used for oil and gas transportation, using the ABAQUS ® software, based on Finite Elements Method (FEM. During the simulation complex phenomena are considerable including: Variation in physical and mechanical properties of materials as a function of temperature, welding speed and the different mechanisms of heat exchange with the environment (convection and radiation were used. These considerations allow a more robust mathematical modeling for the welding process. An analytical heat source proposed by Goldak, to model the heat input in order to characterize the multipass welding through the GTAW (Gas Tungsten Arc Welding process on root and the SMAW (Shielded Metal Arc Welding process for the filling passes were used. So, it was possible to evaluate the effect of each welding pass on the welded joint temperature field, through the temperature peaks and cooling rates values during the welding process.

Galvanic corrosion of beryllium welds

International Nuclear Information System (INIS)

Hill, M.A.; Butt, D.P.; Lillard, R.S.

1997-01-01

Beryllium is difficult to weld because it is highly susceptible to cracking. The most commonly used filler metal in beryllium welds is Al-12 wt.% Si. Beryllium has been successfully welded using Al-Si filler metal with more than 30 wt.% Al. This filler creates an aluminum-rich fusion zone with a low melting point that tends to backfill cracks. Drawbacks to adding a filler metal include a reduction in service temperature, a lowering of the tensile strength of the weld, and the possibility for galvanic corrosion to occur at the weld. To evaluate the degree of interaction between Be and Al-Si in an actual weld, sections from a mock beryllium weldment were exposed to 0.1 M Cl - solution. Results indicate that the galvanic couple between Be and the Al-Si weld material results in the cathodic protection of the weld and of the anodic dissolution of the bulk Be material. While the cathodic protection of Al is generally inefficient, the high anodic dissolution rate of the bulk Be during pitting corrosion combined with the insulating properties of the Be oxide afford some protection of the Al-Si weld material. Although dissolution of the Be precipitate in the weld material does occur, no corrosion of the Al-Si matrix was observed

Automatic welding of stainless steel tubing

Science.gov (United States)

Clautice, W. E.

1978-01-01

The use of automatic welding for making girth welds in stainless steel tubing was investigated as well as the reduction in fabrication costs resulting from the elimination of radiographic inspection. Test methodology, materials, and techniques are discussed, and data sheets for individual tests are included. Process variables studied include welding amperes, revolutions per minute, and shielding gas flow. Strip chart recordings, as a definitive method of insuring weld quality, are studied. Test results, determined by both radiographic and visual inspection, are presented and indicate that once optimum welding procedures for specific sizes of tubing are established, and the welding machine operations are certified, then the automatic tube welding process produces good quality welds repeatedly, with a high degree of reliability. Revised specifications for welding tubing using the automatic process and weld visual inspection requirements at the Kennedy Space Center are enumerated.

Upgraded HFIR Fuel Element Welding System

International Nuclear Information System (INIS)

Sease, John D.

2010-01-01

The welding of aluminum-clad fuel plates into aluminum alloy 6061 side plate tubing is a unique design feature of the High Flux Isotope Reactor (HFIR) fuel assemblies as 101 full-penetration circumferential gas metal arc welds (GMAW) are required in the fabrication of each assembly. In a HFIR fuel assembly, 540 aluminum-clad fuel plates are assembled into two nested annular fuel elements 610 mm (24-inches) long. The welding process for the HFIR fuel elements was developed in the early 1960 s and about 450 HFIR fuel assemblies have been successfully welded using the GMAW process qualified in the 1960 s. In recent years because of the degradation of the electronic and mechanical components in the old HFIR welding system, reportable defects in plate attachment or adapter welds have been present in almost all completed fuel assemblies. In October 2008, a contract was awarded to AMET, Inc., of Rexburg, Idaho, to replace the old welding equipment with standard commercially available welding components to the maximum extent possible while maintaining the qualified HFIR welding process. The upgraded HFIR welding system represents a major improvement in the welding system used in welding HFIR fuel elements for the previous 40 years. In this upgrade, the new inner GMAW torch is a significant advancement over the original inner GMAW torch previously used. The innovative breakthrough in the new inner welding torch design is the way the direction of the cast in the 0.762 mm (0.030-inch) diameter aluminum weld wire is changed so that the weld wire emerging from the contact tip is straight in the plane perpendicular to the welding direction without creating any significant drag resistance in the feeding of the weld wire.

Ultrasonic inspection of austenitic welds

International Nuclear Information System (INIS)

Baikie, B.L.; Wagg, A.R.; Whittle, M.J.; Yapp, D.

1976-01-01

Optical and X-ray metallography combined with ultrasonic testing by compression waves was used for inspection of stainless steel weld metal produced by three different welding techniques. X-ray diffraction showed that each weld possessed a characteristic fibre textured structure which was shown by optical microscopy to be parallel to columnar grain boundaries. Metallographic evidence suggested that the development of fibre texture is due to the mechanism of competitive growth. From observations made as a result of optical metallographic examination the orientation of the fibre axis could be predicted if the weld geometry and welding procedure were known. Ultrasonic velocity and attenuation measurements as a continuous function of grain orientation, made on cylinders machined from weld samples, showed that attenuation was strongly orientation dependent. It was concluded that the sensitivity of ultrasonic inspection to small defects is unlikely to be as high for austenitic welds as for ferritic even when transmission is improved by modifying the welding procedure to improve the ultrasonic transmission. (U.K.)

Twin header bore welded steam generator for pressurized water reactors

International Nuclear Information System (INIS)

Davies, R.J.; Hirst, B.

1979-01-01

A description is given of a pressurized water reactor (PWR) steam generator concept, several examples of which have been in service for up to fourteen years. Details are given of the highly successful service record of this equipment and the features which have been incorporated to minimize corrosion and deposition pockets. The design employs a vertical U tube bundle carried off two horizontal headers to which the tubes are welded by the Foster Wheeler Power Products (FWPP) bore welding process. The factors to be considered in uprating the design to meet the current operating conditions for a 1000 MW unit are discussed. (author)

Challenges to Resistance Welding

DEFF Research Database (Denmark)

Song, Quanfeng

This report originates from the compulsory defense during my Ph.D. study at the Technical University of Denmark. Resistance welding is an old and well-proven technology. Yet the emergence of more and more new materials, new designs, invention off new joining techniques, and more stringent...... requirement in quality have imposed challenges to the resistance welding. More some research and development have to be done to adapt the old technology to the manufacturing industry of the 21st century. In the 1st part of the report, the challenging factors to the resistance welding are reviewed. Numerical...... simulation of resistance welding has been under development for many years. Yet it is no easy to make simulation results reliable and accurate because of the complexity of resistance welding process. In the 2nd part of the report numerical modeling of resistance welding is reviewed, some critical factors...

Weld pool and keyhole dynamic analysis based on visual system and neural network during laser keyhole welding

OpenAIRE

Luo, Masiyang

2014-01-01

In keyhole fiber laser welding processes, the weld pool behavior and keyhole dynamics are essential to determining welding quality. To observe and control the welding process, the accurate extraction of the weld pool boundary as well as the width is required. In addition, because of the cause-and-effect relationship between the welding defects and stability of the keyhole, which is primarily determined by keyhole geometry during the welding process, the stability of keyhole needs to be consid...

IMPROVEMENT OF WELDED CONNECTIONS WITH SIDE LAP WELDS BY REDISTRIBUTION OF ALL-WELD METAL ALONG LENGTHS AND CROSS-SECTIONS THEREOF USING MECHANIZED AND ROBOTIC WELDING SYSTEMS

Directory of Open Access Journals (Sweden)

Pavlov Evgeniy Igorevich

2017-05-01

Full Text Available Experimental study of bearing capacity of samples of two series performed by semiautomatic welding in CO2 on the axis, and by robotic welding machine in mixture (CO2 + Ar, is presented. Welds of constant cross section, welds with extended leg on end sections, and welds in the form of two dowels on end sections were performed. Efficiency of pilot samples of the first series (with extended leg on end sections by way of a smooth transition defined by the ratio of weld metal volume to a crushing load reaches 28 % relative to samples with a leg constant as per length. Samples of the first series with an extended leg on end sections also showed efficiency increased to 17 %. According to the second series samples test results, the exceeding of bearing capacity of the samples performed with an extended leg on end sections by 24 % in comparison with the samples with a leg of constant cross section was determined. Samples of the second series performed in the form of two dowels on end sections demonstrated the exceeding of the relative bearing capacity by 42 % in comparison with the samples with a continuous leg of constant cross-section.

Welding Current Distribution in the Work-piece and Pool in Arc Welding

Directory of Open Access Journals (Sweden)

A. M. Rybachuk

2015-01-01

Full Text Available In order to select the optimal configuration of controlling magnetic fields and build rational construction of magnetic systems, we need to know the distribution of welding current in the molten metal of the weld pool. So the objective of the work is to establish the calculated methods for determining current density in the weld pool during arc welding. The distribution of welding current in the pool depends on the field of the electrical resistance, which is determined by the deformed temperature field while arc moves with the welding speed. The previous works have shown experimentally and by simulation on the conductive paper that deformation of temperature field defines deformation of electric field. On the basis thereof, under certain boundary conditions the problem has been solved to give a general solution of differential equation, which relates the potential distribution to the temperature in the product during arc welding. This solution is obtained under the following boundary conditions: 1 metal is homogeneous; 2 input and output surfaces of heat flux and electric current coincide; 3 input and output surfaces of heat flux and electric current are insulated and equipotential; 4 other (lateral surfaces are adiabatic boundaries. Therefore, this paper pays basic attention to obtaining the analytical solution of a general differential equation, which relates distribution of potential to the temperature in the product. It considers the temperature field of the heat source, which moves at a welding speed with normal-circular distribution of the heat flow at a certain concentration factor. The distribution of current density is calculated on the assumption that the welding current is introduced through the same surface as the heat flux and the distribution of current density corresponds to the normally circular at a certain concentration factor. As a result, we get an expression that allows us to calculate the current density from the known

Visualization of Spot- welding Resistance

Directory of Open Access Journals (Sweden)

Michal Černý

2016-01-01

Full Text Available This contribution devotes to monitoring of processes running during joining of steel sheets by incadescent so called point welding using non-destructive trial method – acoustic emission (AE. The joining process is detailed described within experimental measuring from the point of view of metallurgic effects runnig during weld creation (records obtained by means of AE method. It takes into consideration quality of joined steels within welding data of steel producer. Steel welding (determined by chemical composition during mechanical verification and firmness of welds consider results of measurement AE and fracture effect of point joints. The measurement also demonstrates conclusion about connection of metallurgic processes with material wave effects (AE measurement and their impact on firmness of joint at steel with guaranteed welding, difficult welding and at their potential combination.

Method for welding beryllium

Science.gov (United States)

Dixon, R.D.; Smith, F.M.; O`Leary, R.F.

1997-04-01

A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs.

Method for welding beryllium

International Nuclear Information System (INIS)

Dixon, R.D.; Smith, F.M.; O'Leary, R.F.

1997-01-01

A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs

Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

Directory of Open Access Journals (Sweden)

Koray Yurtisik

2013-09-01

Full Text Available Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure without compromising the welding efficiency. 11.1 mm-thick standard duplex stainless steel plates were joined in a single-pass using this novel technique. Same plates were also subjected to conventional gas metal arc and plasma arc welding processes, providing benchmarks for the investigation of the weldability of the material. In the first place, the hybrid welding process enabled us to achieve less heat input compared to gas metal arc welding. Consequently, the precipitation of secondary phases, which are known to be detrimental to the toughness and corrosion resistance of duplex stainless steels, was significantly suppressed in both fusion and heat affected zones. Secondly, contrary to other keyhole techniques, proper cooling time and weld metal chemistry were achieved during the process, facilitating sufficient reconstructive transformation of austenite in the ferrite phase.

Spot Welding Characterizations With Time Variable

International Nuclear Information System (INIS)

Abdul Hafid; Pinitoyo, A.; History; Paidjo, Andryansyah; Sagino, Sudarmin; Tamzil, M.

2001-01-01

For obtain spot welding used effective data, this research is made, so that time operational of machine increasing. Welding parameters are material classification, electrical current, and weld time. All of the factors are determined welding quality. If the plate more thick, the time must be longer when the current constant. Another factor as determined welding quality are surface condition of electrode, surface condition of weld material, and material classifications. In this research, the weld machine type IP32A2 VI (110 V), Rivoira trademark is characterized

Integrated sensors for robotic laser welding

NARCIS (Netherlands)

Iakovou, D.; Aarts, Ronald G.K.M.; Meijer, J.; Beyer, E.; Dausinger, F; Ostendorf, A; Otto, A.

2005-01-01

A welding head is under development with integrated sensory systems for robotic laser welding applications. Robotic laser welding requires sensory systems that are capable to accurately guide the welding head over a seam in three-dimensional space and provide information about the welding process as

Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

OpenAIRE

Yurtisik,Koray; Tirkes,Suha; Dykhno,Igor; Gur,C. Hakan; Gurbuz,Riza

2013-01-01

Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex mi...

A Study to Increase Weld Penetration in P91 Steel During TIG Welding by using Activating Fluxes

Science.gov (United States)

Singh, Akhilesh Kumar; Kumar, Mayank; Dey, Vidyut; Naresh Rai, Ram

2017-08-01

Activated Flux TIG (ATIG) welding is a unique joining process, invented at Paton Institute of electric welding in 1960. ATIG welding process is also known as flux zoned TIG (FZTIG). In this process, a thin layer of activating flux is applied along the line on the surface of the material where the welding is to be carries out. The ATIG process aids to increase the weld penetration in thick materials. Activating fluxes used in the literature show the use of oxides like TiO2, SiO2, Cr2O3, ZnO, CaO, Fe2O3, and MnO2 during welding of steels. In the present study, ATIG was carried out on P-91 steel. Though, Tungsten Inert Gas welding gives excellent quality welds, but the penetration obtained in such welding is still demanding. P91 steel which is ferritic steel is used in high temperature applications. As this steel is, generally, used in thick sections, fabrication of such structures with TIG welding is limited, due to its low depth of penetration. To increase the depth of penetration in P91while welding with ATIG, the role of various oxides were investigated. Apart from the oxides mentioned above, in the present study the role of B2O3, V2O5 and MgO, during ATIG welding of P91 was investigated. It was seen that, compared to TIG welding, there was phenomenal increase in weld penetration during ATIG welding. Amongst all the oxides used in this study, maximum penetration was achieved in case of B2O3. The measurements of weld penetration, bead width and heat affected zone of the weldings were carried out using an image analysis technique.

Fontainebleau Sand

DEFF Research Database (Denmark)

Leth, Caspar Thrane

2006-01-01

The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand.......The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand....

Residual stress improvement in multi-layer welded plates using water-shower cooling during welding process

International Nuclear Information System (INIS)

Yanagida, Nobuyoshi; Koide, Hiroo

2006-01-01

To reduce tensile residual stress in a welded region, we developed a new welding method that applies a water-shower behind the welding torch. When this method is applied to welding of austenitic stainless steel plates, cooling conditions mainly determine how much the residual stress can be reduced. To determine the conditions, we first used FEM to evaluate the effects of interpass temperature on the residual stress. And we found effective conditions for reducing tensile residual stress. To verify the validity of the conditions, specimens welded with or without water shower cooling were manufactured. Residual stresses of the specimens were experimentally measured. It was found that tensile residual stresses were generated on the surface of the welds and those were reduced in the case that the water-shower was applied. These measurement results agree well with the FEM analyses. It can therefore be concluded that the water-shower cooling during welding is appropriate for reducing tensile residual stress in austenitic stainless steel welding. (author)

Manufacturing and use of spiral welded pipes for high pressure service : state of the art

Energy Technology Data Exchange (ETDEWEB)

Knoop, F.M.; Sommer, B. [Salzgitter GroBrohre GmbH, Salzgitter (Germany)

2004-07-01

This paper provided details of an improved helical seam 2-step (HTS) manufacturing process used to produce spiral welded large diameter pipes for high pressure transmission pipelines. During the process, pipe forming is combined with continuous tack welding and internal and external submerged arc welding at separate welding stations. The pipe forming unit consists of a 3 roll bending system with an outside roller cage used to guarantee the roundness of the pipe. The converging strip edges of the pipe are joined using a continuous shielded arc tack weld. Tack welding is done automatically with a laser-guided weld head. Run-out angles are adjusted by an automatic gap control system. The formed and tack-welded pipes are then fed to computer-controlled welding stations for final welding, where each pipe is rotated with a precise screw-like motion. The same welding materials used for the helical seam are used for the skelp end welding. The process offers more precise root gap control, as well as improved pipe geometry. Use of the process has also increased production rates and improved weld stability. The dimensions of the spiral-weld pipes are adjustable so that any diameter can be produced from a base material of the same width. The pipes can also be coated externally with fusion-bonded epoxy or 3-layer polyethylene/polypropylene. It was concluded that the process is being further refined to support the use of HTS pipes in high-pressure pipelines. New nondestructive testing techniques used to assess the performance of the line pipes were presented, as well as the results from hot and cold bending tests, field weldability trials, and tests related to the safety of spiral pipes. 16 refs., 2 tabs., 12 figs.

Weld metal microstructures of hardfacing deposits produced by self-shielded flux-cored arc welding

International Nuclear Information System (INIS)

Dumovic, M.; Monaghan, B.J.; Li, H.; Norrish, J.; Dunne, D.P.

2015-01-01

The molten pool weld produced during self-shielded flux-cored arc welding (SSFCAW) is protected from gas porosity arising from oxygen and nitrogen by reaction ('killing') of these gases by aluminium. However, residual Al can result in mixed micro-structures of δ-ferrite, martensite and bainite in hardfacing weld metals produced by SSFCAW and therefore, microstructural control can be an issue for hardfacing weld repair. The effect of the residual Al content on weld metal micro-structure has been examined using thermodynamic modeling and dilatometric analysis. It is concluded that the typical Al content of about 1 wt% promotes δ-ferrite formation at the expense of austenite and its martensitic/bainitic product phase(s), thereby compromising the wear resistance of the hardfacing deposit. This paper also demonstrates how the development of a Schaeffler-type diagram for predicting the weld metal micro-structure can provide guidance on weld filler metal design to produce the optimum microstructure for industrial hardfacing applications.

49 CFR 192.225 - Welding procedures.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Welding procedures. 192.225 Section 192.225... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.225 Welding procedures. (a) Welding must be performed by a qualified welder in accordance with welding procedures...

Real-time remote-controlled welding of the inspection nozzle on the Phenix double-wall tank

Energy Technology Data Exchange (ETDEWEB)

Chagnot, C.; Dineghin, G. de; Baude, D.; Delmas, A.; Gauthier, A. [CEA Saclay, Lab. Moderne de Soudage, 91 - Gif sur Yvette (France); Gros, J. [Centrale Phenix, 30 - Bagnols sur Ceze (France); Sommeillier, M. [Comex Nucleaire, 13 - Marseille (France)

2001-07-01

For the ultrasonic non destructive inspection of the vessel shell ring welds in the Phenix reactor, the insert of the NDT instrument needs to drill the double-wall tank, to install and weld nozzles. This last operation is realized by the way of an orbital welding installation. Considering severe environment restraints (irradiation, temperature, space,...), the welding control is made at distance (50 m). To supervise this operation, the welder requires an high quality image of the welding scene. Five nozzles of about 400 mm diameter are distributed on a 12 m-diameter tank. The junction between the nozzle and the tank present a shape of horse saddle and the passes trajectories against the tank wall show a lateral deviation of several millimeters. To take care of this deviation and of eventual geometrical defects, the welder adjust the torch position during welding. For that he needs an adapted information. The ''Laboratoire Moderne de Soudage'' inside CEA/CEREM has designed, validated and provided a new Computer-Assisted Welding for real-time remote-controlled orbital welding. Video cameras and a laser diode module were installed on the orbital installation for the watching of the welding scene. An image processing unit of new generation gives the real-time measurement of the distance between the torch and the wall tank. The control of the torch position is particularly significant to guarantee the good welding pass sequence. With this system, the position precision can reach 0,1 mm. (author)

Real-time remote-controlled welding of the inspection nozzle on the Phenix double-wall tank

International Nuclear Information System (INIS)

Chagnot, C.; Dineghin, G. de; Baude, D.; Delmas, A.; Gauthier, A.; Gros, J.; Sommeillier, M.

2001-01-01

For the ultrasonic non destructive inspection of the vessel shell ring welds in the Phenix reactor, the insert of the NDT instrument needs to drill the double-wall tank, to install and weld nozzles. This last operation is realized by the way of an orbital welding installation. Considering severe environment restraints (irradiation, temperature, space,...), the welding control is made at distance (50 m). To supervise this operation, the welder requires an high quality image of the welding scene. Five nozzles of about 400 mm diameter are distributed on a 12 m-diameter tank. The junction between the nozzle and the tank present a shape of horse saddle and the passes trajectories against the tank wall show a lateral deviation of several millimeters. To take care of this deviation and of eventual geometrical defects, the welder adjust the torch position during welding. For that he needs an adapted information. The ''Laboratoire Moderne de Soudage'' inside CEA/CEREM has designed, validated and provided a new Computer-Assisted Welding for real-time remote-controlled orbital welding. Video cameras and a laser diode module were installed on the orbital installation for the watching of the welding scene. An image processing unit of new generation gives the real-time measurement of the distance between the torch and the wall tank. The control of the torch position is particularly significant to guarantee the good welding pass sequence. With this system, the position precision can reach 0,1 mm. (author)

GMAW (Gas Metal Arc Welding) process development for girth welding of high strength pipelines

Energy Technology Data Exchange (ETDEWEB)

Rajan, Vaidyanath; Daniel, Joe; Quintana, Marie [The Lincoln Electric Company, Cleveland, OH (United States); Chen, Yaoshan [Center for Reliable Energy Systems (CRES), Dublin, OH (United States); Souza, Antonio [Lincoln Electric do Brasil, Guarulhos, SP (Brazil)

2009-07-01

This paper highlights some of the results and findings from the first phase of a consolidated program co-funded by US Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) and Pipeline Research Council Inc (PRCI) to develop pipe weld assessment and qualification methods and optimize X 100 pipe welding technologies. One objective of the program is to establish the range of viable welding options for X 100 line pipe, and define the essential variables to provide welding process control for reliable and consistent mechanical performance of the weldments. In this first phase, a series of narrow gap girth welds were made with pulsed gas metal arc welding (GMAW), instrumented with thermocouples in the heat affected zone (HAZ) and weld metal to obtain the associated thermal profiles, and instrumented to measure true energy input as opposed to conventional heat input. Results reveal that true heat input is 16%-22% higher than conventional heat input. The thermal profile measurements correlate very well with thermal model predictions using true energy input data, which indicates the viability of treating the latter as an essential variable. Ongoing microstructural and mechanical testing work will enable validation of an integrated thermal-microstructural model being developed for these applications. Outputs from this model will be used to correlate essential welding process variables with weld microstructure and hardness. This will ultimately enable development of a list of essential variables and the ranges needed to ensure mechanical properties are achieved in practice, recommendations for controlling and monitoring these essential variables and test methods suitable for classification of welding consumables. (author)

Creep deformation behavior of weld metal and heat affected zone on 316FR steel thick plate welded joint

International Nuclear Information System (INIS)

Hongo, Hiromichi; Yamazaki, Masayoshi; Watanabe, Takashi; Kinugawa, Junichi; Tanabe, Tatsuhiko; Monma, Yoshio; Nakazawa, Takanori

1999-01-01

Using hot-rolled 316FR stainless plate (50 mm thick) and 16Cr-8Ni-2Mo filler wire, a narrow-gap welded joint was prepared by GTAW (gas tungsten arc welding) process. In addition to conventional round bar specimens of base metals and weld metal, full-thickness joint specimens were prepared for creep test. Creep tests were conducted at 550degC in order to examine creep deformation and rupture behavior in the weld metal of the welded joint. Creep strain distribution on the surface of the joint specimen was measured by moire interferometry. In the welded joint, creep strength of the weld metal zone apart from the surface was larger than that in the vicinity of the surface due to repeating heat cycles during welding. Creep strain and creep rate within the HAZ adjacent to the weld metal zone were smaller than those within the base metal zone. Creep rate of the weld metal zone in the welded joint was smaller than that of the weld metal specimen due to the restraint of the hardened HAZ adjacent to the zone. The full-thickness welded joint specimens showed longer lives than weld metal specimens, though the lives of the latter was shorter than those of the base metal (undermatching). In the full-thickness welded joint specimen, crack started from the last pass layer of the weld metal zone and fracture occurred at the zone. From the results mentioned above, in order to evaluate the creep properties of the welded joint correctly, it is necessary to conduct the creep test using the full-thickness welded joint specimen which includes the weakest zones of the weld metal, the front and back sides of the plate. (author)

Underwater welding of steel

International Nuclear Information System (INIS)

Ibarra, S.; Olson, D.L.

1992-01-01

A fundamental basis to understand the behavior of wet underwater welding of steel is introduced. Both the pyrometallurgical and physical metallurgy concepts are discussed. Modifications of welding consumables and practice are suggested. This chapter promotes further contributions of meatllurgical research to improve and promote wet underwater welding. (orig.)

The investigation of typical welding defects for 5456 aluminum alloy friction stir welds

International Nuclear Information System (INIS)

Chen Huabin; Yan Keng; Lin Tao; Chen Shanben; Jiang Chengyu; Zhao Yong

2006-01-01

The external factors on the friction stir welding defects are so abundant that the experiments of friction stir welding were conducted for 5456 aluminum alloy. With the changes of the tool tilt angle and material condition, defects can be generated. These defects can be conventional ones (lack of penetration or voids), or lazy S, which are unique to friction stir welding. However, the origin of the defects remains an area of uncertainty. In this study, an attempt has been made to investigate the formation of these defects. The typical welding defects of friction stir welding joint for 5456 aluminum alloy were analyzed and discussed, respectively, by using optical microscopy (OM), energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscope (SEM). The microscopic examination of the nugget zone and fracture location of the weld confirms that the tilt angle can change the plastic material flow patterns in the stir zone and accordingly control the weld properties. In addition, the oxide layer from the initial butt surface during FSW is dispersed at the grain boundary. These A1 2 O 3 particles are actually the major cause of failure of the joint

Laser welding engineering

International Nuclear Information System (INIS)

Bhieh, N. M.; El Eesawi, M. E.; Hashkel, A. E.

2007-01-01

Laser welding was in its early life used mainly for unusual applications where no other welding process would be suitable that was twenty five years ago. Today, laser welding is a fully developed part of the metal working industry, routinely producing welds for common items such as cigarette lighters, which springs, motor/transformer lamination, hermetic seals, battery and pacemaker cans and hybrid circuit packages. Yet very few manufacturing engineering have seriously considers employing lasers in their own operations. Why? There are many reasons, but a main one must be not acquainted with the operation and capabilities of a laser system. Other reasons, such as a relatively high initial cost and a concern about using lasers in the manufacturing environment, also are frequently cited, and the complexity of the component and flexibility of the light delivery system. Laser welding could be used in place of many different standard processes, such as resistance (spot or seam), submerged arc, RF induction, high-frequency resistance, ultrasonic and electronic and electron-beam. while each of these techniques has established an independent function in the manufacturing world, the flexible laser welding approach will operate efficiently and economically in many different applications. Its flexibility will even permit the welding system to be used for other machining function, such as drilling, scribing, sealing and serializing. In this article, we will look at how laser welding works and what benefits it can offer to manufacturing engineers. Some industry observers state that there are already 2,000 laser machine tools being used for cutting, welding and drilling and that the number could reach 30,000 over the next 15 years as manufacturing engineers become more aware of the capabilities of lasers [1). While most laser applications are dedicated to one product or process that involves high-volume, long-run manufacturing, the flexibility of a laser to supply energy to hard

Effect of welding processes on the impression creep resistance of type 316 LN stainless steel weld joints

International Nuclear Information System (INIS)

Vasudevan, M.; Vasantharaja, P.; Sisira, P.; Divya, K.; Ganesh Sundara Raman, S.

2016-01-01

Type 316 LN stainless steel is the major structural material used in the construction of fast breeder reactors. Activated Tungsten Inert Gas (A-TIG) welding , a variant of the TIG welding process has been found to enhance the depth of penetration significantly during autogenous welding and also found to enhance the creep rupture life in stainless steels. The present study aims at comparing the effect of TIG and A-TIG welding processes on the impression creep resistance of type 316 LN stainless steel base metal, fusion zone and heat affected zone (HAZ) of weld joints. Optical and TEM have been used to correlate the microstructures with the observed creep rates of various zones of the weld joints. Finer microstructure and higher ferrite content was observed in the TIG weld joint fusion zone. Coarser grain structure was observed in the HAZ of the weld joints. Impression creep rate of A-TIG weld joint fusion zone was almost equal to that of the base metal and lower than that of the TIG weld joint fusion zone. A-TIG weld joint HAZ was found to have lower creep rate compared to that of conventional TIG weld joint HAZ due to higher grain size. HAZ of the both the weld joints exhibited lower creep rate than the base metal. (author)

Tensile Properties of Friction Stir Welded Joints of AA 2024-T6 Alloy at Different Welding Speeds

Science.gov (United States)

Avula, Dhananjayulu; Devuri, Venkateswarlu; Cheepu, Muralimohan; Dwivedi, Dheerendra Kumar

2018-03-01

The influence of welding speed on the friction stir welded joint properties of hardness, tensile properties, defects and microstructure characterization are studied in the present study. The friction stir welding was conducted on AA2014-T6 heat treated alloy with 5 mm thickness plate in butt joint configuration. The welding speed was varied from 8 mm/min to 120 mm/min at the fixed travel speed and load conditions. It is observed that the welding speeds at higher rate with wide range can be possible to weld this alloy at higher rates of tool revolution suggesting that the inherent capability of friction stir welding technique for aluminum 2014 alloys. The strength of the joints gradually increases with enhancing of welding speed. The micro structural observations exhibited the formation of equiaxed grains in the stir zone and slightly in the thermo-mechanically affected zone. In addition, the size of the grains decreases with increase in welding speed owing to the presence of low heat input. Hence the hardness of the joints slightly increased in the stir zones over the other zones of the weld nugget. The joint strength initially increases with the welding speed and starts to decreases after reaching to the maximum value. The relationship between the welding conditions and friction stir welded joint properties has been discussed.

Metals welding by using laser

International Nuclear Information System (INIS)

Al-Qaisy, R.A.W.

1991-01-01

In the present work, same welding ''conduction limited type'' under atmospheric conditions was performed using pulsed Ng:YAG laser to weld; low carbon steel (LCS), stainless steel (304) (SUS304), stainless steel (303) (SUS303), and brass. Microstructure of welded zone, heat affected zone (HAZ), and the laser energy on penetration depth and effective diameter were studied. Tensile test, micro-hardness, and surface roughness of welded and parent metals were also dealt with. Melting efficiency was worked out and an under vacuum seam welding of low carbon steel has been accomplished. Finally spot welding of aluminium tungsten, and platinium wires were employed using different layer energies. 34 tabs.; 82 figs.; 51 refs.; 1 app

Corrosion of carbon steel welds

International Nuclear Information System (INIS)

Daniel, B.

1988-09-01

This report assesses the factors which cause preferential attack to occur in carbon steel fusion welds. It was concluded that the main factors were: the inclusion content of the weld metal, the potential of the weld metal being less noble than that of the parent, and the presence of low-temperature transformation products in the heat-affected zone of the weld. These factors should be minimized or eliminated as appropriate so that the corrosion allowances determined for carbon steel waste drums is also adequate for the welds. An experimental/theoretical approach is recommended to evaluate the relative corrosion resistance of welds prepared from BS 4360 grade 43A steel to that of the parent material. (author)

MFDC - technological improvement in resistance welding controls

Energy Technology Data Exchange (ETDEWEB)

Somani, A.K.; Naga Bhaskar, V.; Chandramouli, J.; Rameshwara Rao, A. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderabad (India)

2008-07-01

Among the various Resistance Welding operations carried out in the production line of a fuel bundle end plug welding is the most critical operation. Welding controllers play a very vital role in obtaining consistent weld quality by regulating and controlling the weld current. Conventional mains synchronized welding controllers are at best capable of controlling the weld current at a maximum speed of the mains frequency. In view of the very short welding durations involved in the various stages of a fuel bundle fabrication, a need was felt for superior welding controllers. Medium Frequency Welding Controllers offer a solution to these limitations in addition to offering other advantages. Medium Frequency power sources offer precise welding current control as they regulate and correct the welding current faster, typically twenty times faster when operated at 1000Hz. An MFDC was employed on one of the welding machines and its performance was studied. This paper discusses about the various advantages of MFDCs with other controllers employed at NFC to end plug welding operation. (author)

Microstructural examination of Zr-2.5%Nb alloy welds made by pulsed Nd:YAG laser and TIG welding technique

International Nuclear Information System (INIS)

Bhatt, R.B.; Varma, P.V.S.; Panakkal, J.P.; Srivastava, D.; Dey, G.K.

2009-01-01

The paper describes the weld microstructure of Zr-2.5%Nb alloy material. Bead on plate welds were made using pulsed Nd:YAG laser and TIG welding technique at different parameters. These welds were characterized at macro and microstructural level. Weld pools of Pulsed Laser and TIG welds were not resolved by optical microscopy. SEM too did not reveal much. Orientation imaging microscopy could reveal the presence of fine martensite. It was observed that microstructure is very sensitive to welding parameters. Microhardness studies suggested formation of martensite in the weld pool. It was also observed that laser welds had very sharp weld pool boundary as compared to TIG welds. Variation in microhardness of the weldment is seen and is influenced by overlapping of weld spots causing thermal treatment of previously deposited spots. (author)

Recent Corrosion Research Trends in Weld Joints

International Nuclear Information System (INIS)

Kim, Hwan Tae; Kil, Sang Cheol; Hwang, Woon Suk

2007-01-01

The increasing interest in the corrosion properties of weld joints in the corrosive environment is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency welding process to produce welds. Welding plays an important role in the fabrication of chemical plants, nuclear power plant, ship construction, and this has led to an increasing attention to the corrosion resistant weld joints. This paper covers recent technical trends of welding technologies for corrosion resistance properties including the COMPENDEX DB analysis of welding materials, welding process, and welding fabrications

Machine for welding solar cell connections

Energy Technology Data Exchange (ETDEWEB)

Lorans, D.Y.

1977-08-09

A machine for welding a connection wire over a solar cell electrode is described which comprises a base, a welding mount for the solar cell which is supported on the base, means for holding the solar cell on the welding mount, welding electrodes, means to lower the welding electrodes over the solar cell and the connection wire superimposed thereon, means for applying electric current pulses to said welding electrodes. It is characterized by the fact that it further comprises means for imparting to said mount an alternating transverse movement in relation to said base before and during the welding operation.

Development of automatic laser welding system

International Nuclear Information System (INIS)

Ohwaki, Katsura

2002-01-01

Laser are a new production tool for high speed and low distortion welding and applications to automatic welding lines are increasing. IHI has long experience of laser processing for the preservation of nuclear power plants, welding of airplane engines and so on. Moreover, YAG laser oscillators and various kinds of hardware have been developed for laser welding and automation. Combining these welding technologies and laser hardware technologies produce the automatic laser welding system. In this paper, the component technologies are described, including combined optics intended to improve welding stability, laser oscillators, monitoring system, seam tracking system and so on. (author)

Probing weld quality monitoring in friction stir welding through characterization of signals by fractal theory

Energy Technology Data Exchange (ETDEWEB)

Das, Bipul; Bag, Swarup; Pal, Sukhomay [Indian Institute of Technology Guwahati, Assam (India)

2017-05-15

Providing solutions towards the improvisation of welding technologies is the recent trend in the Friction stir welding (FSW) process. We present a monitoring approach for ultimate tensile strength of the friction stir welded joints based on information extracted from process signals through implementing fractal theory. Higuchi and Katz algorithms were executed on current and tool rotational speed signals acquired during friction stir welding to estimate fractal dimensions. Estimated fractal dimensions when correlated with the ultimate tensile strength of the joints deliver an increasing trend with the increase in joint strength. It is observed that dynamicity of the system strengthens the weld joint, i.e., the greater the fractal dimension, the better will be the quality of the weld. Characterization of signals by fractal theory indicates that the single-valued indicator can be an alternative for effective monitoring of the friction stir welding process.

Probing weld quality monitoring in friction stir welding through characterization of signals by fractal theory

International Nuclear Information System (INIS)

Das, Bipul; Bag, Swarup; Pal, Sukhomay

2017-01-01

Providing solutions towards the improvisation of welding technologies is the recent trend in the Friction stir welding (FSW) process. We present a monitoring approach for ultimate tensile strength of the friction stir welded joints based on information extracted from process signals through implementing fractal theory. Higuchi and Katz algorithms were executed on current and tool rotational speed signals acquired during friction stir welding to estimate fractal dimensions. Estimated fractal dimensions when correlated with the ultimate tensile strength of the joints deliver an increasing trend with the increase in joint strength. It is observed that dynamicity of the system strengthens the weld joint, i.e., the greater the fractal dimension, the better will be the quality of the weld. Characterization of signals by fractal theory indicates that the single-valued indicator can be an alternative for effective monitoring of the friction stir welding process.

MINAC radiography performed on susquehanna Steam Electric Station Unit 1

International Nuclear Information System (INIS)

Bognet, J.C.

1986-01-01

Ten welds were volumetrically examined with a manual and automated ultrasonic (UT) system during a Susquehanna Steam Electric Station (SES) Unit 1 preservice inspection. The automated system had been recently developed and several problems were encountered in this first field application. The ten welds examined had a Sweepolet-to-Risor weld configuration, which further complicated the examination effort. This weld configuration has corrosion-resistant cladding applied to the outside and inside circumference and, as a result of an installation/removal/reinstallation sequence during plant construction, is often referred to as the double weld. After several attempts to obtain interpretable UT data failed (e.g., repeatable data), the examination effort was terminated. PP and L opted to pursue using the Miniature Linear Accelerator (MINAC) to perform radiographic examination. The results were referenced in the Susquehanna SES Unit 1 outage summary report and submitted to the NRC. The total effort was viewed as a complete success with no impact to the overall outage duration. All welds previously attempted by automated and manual UT were successfully examined using the MINAC

Advantages of MAG-STT Welding Process for Root Pass Welding in the Oil and Gas Industry

Directory of Open Access Journals (Sweden)

Pandzic Adi

2016-02-01

Full Text Available This paper describesthe basics of modern MAG-STT welding process and its advantages for root pass welding of construction steels in oil and gas industry. MAG-STT welding process was compared with competitive arc welding processes (SMAW and TIG, which are also used for root pass welding on pipes and plates. After experimental tests, the obtained results are analyzed and presented in this paper

Discussion on Integration of Welding Coordinator in Welding Quality System of KEPIC(Korea Electric Power Industry code)

Energy Technology Data Exchange (ETDEWEB)

Joo, Hyun-Jae; Sohn, Myoung-Sung; Cho, Kyoung-Youn; Kim, Jong-Hae [Korea Electric Association, Seoul (Korea, Republic of)

2015-05-15

The welding quality system of KEPIC-MQW 'Welding Qualification' referencing ASME BPVC Sec.IX, Part QW requires welding procedures and performance qualification of welder or welding operator excluding welding coordinator. It means that there is potential possibility of any problem in process of welding on nuclear power plants or shop in absence of an welding coordinator who can resolve welding troubles. Therefore, the integration of welding coordinators in the welding quality system of KEPIC can improve welding quality and enhance safety of construction and management of power plants. The introduction of welding coordinator requirement would put economic problems on manufactures for new employment and subsequent management works (eg. training) and field problems making authorized nuclear inspectors to be confused on inspection work scopes. Those predictable problems are expected to be minimized or eliminated through public hearings and/or seminars with regulatory body, the owner, and manufacturers and, most significantly, cooperation with related KEPIC committees. The revision draft was reviewed and discussed with personnel in nuclear industry by holding three workshop and public hearings from 2011 to 2012 and by having a presentation in 2014 KEPIC-Week. Industrial consensus on need for integration of welding coordinators in welding quality system of KEPIC was performed by reasons that it would improve welding quality, guarantee welding reliability, advance expertise, and help export to abroad. However, economic problems on manufacturers for new employment and subsequent management works, for example training, are predicted. Therefore, introduction in stages for minimizing industrial impact regarding manufacturer's scale and permission of utilizing external welding coordinator for small scale manufacturers are required. A new draft version of KEPIC-MQW (if possible, appendices of MQW) including requirements and directives for solving these economic

Blanket Cooling Plates Mock-ups Manufactured in different Diffusion Weld Setup

International Nuclear Information System (INIS)

Von Der Weth, A.; Aktaa, J.

2007-01-01

Full text of publication follows: The breeding blanket box is considered as one of the most important components of a future fusion power plant. It will be assembled by so called cooling plates (CP) with a system of internal cooling channels. Such a CP is produced by two symmetric half pieces with half milled-in channels. Both pieces will be joined by a diffusion weld (DW) process. Within recent years a two step DW process for different EUROFER batches has been developed. It has been first applied to small laboratory scaled samples with dimensions of 25 mm x 30 mm x 40 mm. Then the DW process had then been successfully transferred to so called compact mock ups which are small CPs with dimensions of 67 mm x 70 mm x 50 mm. As third step this process has been used to manufacture a CP (465 mm x 205 mm x 50 mm) of a breeder unit in an industrial uniaxial diffusion weld setup. This paper treats the manufacturing sequence of a cooling plate and a first wall mock up in an industrial hot isostatic pressing (HIP) setup. The firstly laboratory specimens scaled diffusion weld process has been adjusted to different cooling channel dimensions and a different DW setup. The weld quality is investigated by tensile and Charpy impact testing. This allows comparison of the weld quality of mock ups welded in different DW setups. (authors)

Report Summarizing the Effort Required to Initiate Welding of Irradiated Materials within the Welding Cubicle

Energy Technology Data Exchange (ETDEWEB)

Frederick, Greg [Electric Power Research Institute (EPRI), Palo Alto, CA (United States); Sutton, Benjamin J. [Electric Power Research Institute (EPRI), Palo Alto, CA (United States); Tatman, Jonathan K. [Electric Power Research Institute (EPRI), Palo Alto, CA (United States); Vance, Mark Christopher [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smith, Allen W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Clark, Scarlett R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, Roger G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, Jian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hu, Xunxiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gibson, Brian T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-06-01

The advanced welding facility within a hot cell at the Radiochemical Engineering Development Center of Oak Ridge National Laboratory (ORNL), which has been jointly funded by the U.S. Department of Energy (DOE), Office of Nuclear Energy, Light Water Reactor Sustainability Program and the Electric Power Research Institute, Long Term Operations Program and the Welding and Repair Technology Center, is in the final phase of development. Research and development activities in this facility will involve direct testing of advanced welding technologies on irradiated materials in order to address the primary technical challenge of helium induced cracking that can arise when conventional fusion welding techniques are utilized on neutron irradiated stainless steels and nickel-base alloys. This report details the effort that has been required since the beginning of fiscal year 2017 to initiate welding research and development activities on irradiated materials within the hot cell cubicle, which houses welding sub-systems that include laser beam welding (LBW) and friction stir welding (FSW) and provides material containment within the hot cell.

Development of remote laser welding technology

International Nuclear Information System (INIS)

Kim, Soo-Sung; Kim, Woong-Ki; Lee, Jung-Won; Yang, Myung-Seung; Park, Hyun-Soo

1999-01-01

Various welding processes are now available for end cap closure of nuclear fuel element such as TIG(Tungsten Inert Gas) welding, magnetic resistance welding and laser welding. Even though the resistance and TIG welding process are widely used for manufacturing of the commercial fuel elements, it can not be recommended for the remote seal welding of fuel element at PIE facility due to its complexity of the electrode alignment, difficulty in the replacement of parts in the remote manner and its large heat input for thin sheath. Therefore, Nd:YAG laser system using the optical fiber transmission was selected for Zircaloy-4 end cap welding. Remote laser welding apparatus is developed using a pulsed Nd:YAG laser of 500 watt average power with optical fiber transmission. The laser weldability is satisfactory in respect of the microstructures and mechanical properties comparing with the TIG and resistance welding. The optimum operation processes of laser welding and the optical fiber transmission system for hot cell operation in remote manner have been developed. (author)

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

Science.gov (United States)