Showing papers on "Weldability published in 1996"

High-strength line-pipe steel having low yield ratio and excellent low-temperature toughness

Abstract: An ultrahigh-strength and low-yield-ratio line-pipe steel being excellent in HAZ toughness and field weldability and having a tensile strength of at least 950 MPa (exceeding the API Specification 100). The steel comprises a low-C-high-Mn-Ni-Mo-Nb-trace Ti steel, further selectively contains if necessary B, Cu, Cr and V, and has as the microstructure a hard-soft two-phase mixed structure comprising martensite/bainite and 20-90 % of ferrite, the ferrite containing 50-100 % of worked ferrite and having a grain diameter of 5 νm or less. It has thus become possible to produce an ultrahigh-strength and low-yield-ratio line-pipe steel (exceeding the API Specification 100) excellent in low-temperature toughness and field weldability. As a result, it has become possible to improve the pipeline safety remarkably and to improve the pipe-lining performance and conveying efficiency largely.

Carbon and Alloy Steels

Abstract: Carbon and alloy steels are the workhorse of structural materials in modern engineering because of their very reasonable costs coupled with their many and varied properties that allow their use in such large array of applications. It's very easy to take steel for granted and forget how much it's relied upon in critical uses such as cars, bridges, buildings, landing gear assemblies, and more. It's what makes Carbon and Alloy Steels such an important Specialty Handbook series, it places special emphasis on the processing and service characteristics of steel. You'll find detailed, yet practical information that will help you select the best grade for a particular environment or application. There are in-depth reviews of formability, weldability, machinability, and hardenability of the various steel grades. You'll also discover how adding certain alloys can significantly improve steel processing. The strength and toughness section has been greatly expanded with more coverage than ever before of corrosion fatigue. You'll have access to extensive reports detailing which steels are more susceptable to environmental damage such as stress-corrosion and hydrogen embrittlement. Temperature effects relating to mechanical properties and corrosion are also discussed. As a special feature, entirely new articles on steels for specific applications like bearings, gears, automotive, oil and gas pipelines, and more are also discussed. Not only are material requirements covered, but applicable codes, standards and specifications as well. You'll learn what problems and failures others have experienced and what you can do to avoid similar difficulties.

Weldable high-tensile steel excellent in low-temperature toughness

Abstract: A high-tensile steel that comprises a low-C-high-Mn-Ni-Mo-trace-Ti steel, further contains Cu, B, Cr, Ca, V and other elements, and has as the microstructure either a mixed tempered martensite/bainite structure containing at least 60 % of tempered martensite resulting from the transformation of nonrecrystallized austenite having an average austenite grain diameter (dη) of 10 νm or less, or at least 90 % of tempered martensite resulting from the transformation of nonrecrystallized austenite. By regulating the P value to be within the range of 1.9 to 4.0, the steel is excellent in low-temperature toughness, HAZ toughness and field weldability in, e.g., the cold district and has a tensile strength of at least 950 MPa (exceeding the API Specification 100).

Production of seamless steel tube

Abstract: PROBLEM TO BE SOLVED: To produce a seamless steel tube minimal in the dispersion of mechanical properties, excellent in weldability, and having high strength and high toughness by performing specific direct quench-and-temper treatment at the time of hot rolling for a steel having a composition in which specific amounts of C, Si, Mn, Al, and optional elements are contained and the amounts of impurities are controlled. SOLUTION: A steel, which has a composition containing, by weight, 0.02-0.15% C, 0.1-1.5% Si, 0.5-2% Mn, and 0.001-0.5% sol.Al, also containing, as optional elements, prescribed amounts of Cr, Mo, Ni, Ti, Nb, V, Zr, Ca, Cu, and B, and having the balance Fe with inevitable impurities in which respective amounts of P, S, N, O, etc., are controlled, is used. This steel is subjected to hot piercing and rolling and worked into seamless steel tube. At this time, the steel tube is finished at ≥40% reduction of area at 800-1050°C and allowed to stay in the state in a heating furnace of 850-1100°C for 3sec to 30min. Then, the steel tube is directly hardened at R°C/sec average cooling rate to 800-500°C, represented by inequality I. Further, the steel tube is tempered under the conditions represented by inequalities II or III, according to its wall thickness t(mm). COPYRIGHT: (C)1997,JPO

Ultrahigh strength cold rolled steel sheet and its production

Abstract: PROBLEM TO BE SOLVED: To obtain a high strength steel sheet excellent in delayed fracture resistance after parts forming without causing deterioration in workability and weldability required of machine parts by specifying the composition of a steel sheet, applying decarburizing treatment to the steel sheet during annealing, and forming a ferrite layer in the surface layer and a bainite.martensite layer in the inner layer. SOLUTION: A steel, having a composition consisting of, by weight, 0.05-0.20% C, 0.0001-0.030% P, 0.001-0.050% S, 0.001-0.100% Al, 0.0002-0.0050% N, one or ≥2 kinds among 0.10-2.50% Si, 0.5-3.50% Mn, 0.10-1.5% Cr, 0.10-1.5% Mo, and 0.001-0.005% B, and the balance Fe with inevitable impurities, is used. This steel is hot-rolled, descaled, and cold-rolled, followed by continuous annealing. At this time, the resultant steel sheet is subjected to decarburizing treatment, by which each surface layer part, in the region between the surface or the rear surface and a position at a depth of 0.010-0.20mm per side from the surface or the rear surface of the steel sheet, becomes composed essentially of ferrite and also the inner layer part becomes composed essentially of bainite.martensite. COPYRIGHT: (C)1998,JPO

Nd: YAG laser beam welding of coated steels using a modified lap joint geometry

Abstract: The weldability of coated sheet steels by Nd:YAG lasers has been examined using a 250-W pulsed laser, a 1 -kW pulsed laser and a 2-kW continuous wave (CW) laser. Seam welds were produced in 0.75-mm-thick (23- gauge) galvanized and galvannealed sheet steels using a modified lap-joint configuration consisting of a groove-shaped projection in the top sheet of the joint. Experiments were performed to assess the effects on weld quality of coating type, groove-projection dimensions and laser process parameters. Good quality welds, which failed at levels comparable to the base metal in shear tensile tests, were made over a wide range of conditions using the CW Nd:YAG laser, but could only be produced using a limited range of process conditions with the two pulsed lasers. Using the CW laser at a mean power of 1600 W, good quality welds could be produced at speeds up to 60 mm/s (144 in./min). In comparison, the maximum acceptable welding speed when using the 250-W pulsed laser at 220 W laser mean power was just 2.4 mm/s (5.4 in./min). The melting ratios of the welds produced with the CW laser were found to be about 0.25, while they were approximately 0.10 for the welds produced using the pulsed lasers. Finally, the quality of welds produced was not affected by the dimensions of the groove projection or by the coating type.

Production of steel tube for air bag, having high strength and high toughness

Abstract: PROBLEM TO BE SOLVED: To produce a steel tube having high dimensional accuracy, excellent in workability and weldability, and suitable for parts for an air bag, requiring high strength and high toughness. SOLUTION: A steel, having a composition consisting of 0.05-0.15% C, ≤0.50% Si, 0.30-2.00% Mn, ≤0.020% P, ≤0.020% S, ≤0.10% Al, and the balance Fe with inevitable impurities, is used. After tube making, the resultant steel tube is hardened at 850-1000°C and, cold-worked to prescribed size and used in this as-cold-worked state, or, after cold working annealing treatment is applied. By this method, the steel tube, which has high strength, high toughness, and high dimensional accuracy, enough to be used as an accumulator for an air bag, and also has excellent workability and weldability, can be obtained. COPYRIGHT: (C)1998,JPO

Laser weldability analysis of high-speed optical transmission device packaging

Abstract: A 2.5 Gb/s distributed feedback laser diode (DFB-LD) module was used as a test package to develop laser welding techniques. Various package weld joint geometries, such as lap, fillet, butt, and fillet-lap, were designed and welded to investigate the optimal package configuration that leads to the maximum coupling efficiency and minimum weld shift. Furthermore, the welded joints at a given set of laser parameters were cross-sectioned for metallurgical analysis, such as weld penetration and microcracks, for verification of the weld joint integrity. Through such analysis, some important laser welding parameters, such as depth-of-penetration (DOP), heat-affected zone (HAZ), shear-strength, and solidification formation of the weld pool were analyzed. Also, as the result of investigating 56 laser welded DFB-LD submodules, optimal laser parameters, and the suitable joint geometry for this package could be determined with the average weld shift less than 0.19 dB, which translates to less than 1.0 /spl mu/m in radial displacement. These laser welded packages exhibited an excellent tracking stability during environmental testing, which consequently resulted in obtaining a desirable bit-error rate (BER) during the data transmission performance analysis.

The effect of welding on the properties of advanced 9–12%Cr steels

Abstract: There are strong environmental and economic pressures to increase the thermal efficiency of fossil fuel fired power stations, and this has led to a steady increase in steam temperatures and pressures resulting in worldwide plans for ultrasupercritical power plants. Basic investigations on the weldability of advanced 9–12%Cr steels which are either currently in use or which are intended to fulfil this requirement were performed on pipes of P91, E911 and a tungsten containing cast steel G-X 12 CrMoWVNbN 10 1 1. Gleeble simulations representing the manual metal arc welding process were applied to produce HAZ simulated microstructures. After different post-weld heat treatments they were tested using hardness tests, metallographic investigations, constant strain rate tests, and creep tests. Particular attention was given to the softening effect in the HAZ and its influence on the creep resistance of the welded material. This decrease, shown by simulated and manufacturing welded samples, seems to be les...

Ferritic stainless steel excellent in weldability

Abstract: PROBLEM TO BE SOLVED: To provide a ferritic stainless steel in which deterioration in workability caused by coarse grains is prevented in the weld zone of ferritic stainless steel and excellent in weldability. SOLUTION: This ferritic stainless steel excellent in weldability has a layer structure consisting of two or more kinds of compositions containing, by mass, 0.0005 to 0.08% C, 0.01 to 1% Si, 0.01 to 1% Mn, <0.04% P, 0.0001 to 0.01% S, 10 to 25% Cr, 0.0005 to 0.08% N and 0.0005 to 0.01% Mg, furthermore containing one or two kinds of 0.01 to 0.8% Ti and 0.005 to 0.2% Al, and the balance inevitable impurities, also containing one or two kinds of Ti and Al and Mg and containing oxides with the grain size of 0.05 to 5 μm by a distribution density of ≥3 pieces/mm2 in the steel. COPYRIGHT: (C)2001,JPO

Friction welding of Al-Al, Al-steel, and steel-steel samples

Abstract: Friction welding of Al- Al, Al- steel, and steel- steel studs is compared. Transient heat generation and temperature rise during the welding process were modeled. Tensile tests and microhardness measurements across the weld zone were carried out. The metallurgical changes in the heat- affected zone were examined by SEM. Temperature rise at the interface plane was computed and related to weld properties. The affecting parameters on weld quality were identified by statistical analysis. Results show that interaction of weld parameters significantly affect yield, tensile, and breaking strength, and the heat- affected zone on the Al side is wider for Al-steel welds.

Process for improving the formability and weldability properties of zinc coated sheet steel

Abstract: A post plating or post coating method for improving formability and weldability properties in sheet steel product having a protective zinc or zinc alloy layer formed on at least one surface thereof. The steps of the method comprise immersing the sheet steel product into a bath containing at least zinc to apply the protective layer, removing the sheet steel product from the bath, the sheet steel product having a protective zinc or zinc alloy layer formed on at least one surface thereof, and applying an alkaline solution to the protective layer to form a zinc oxide layer thereon, the alkaline solution being applied at a location outside the bath.

Heavy-wall structural steel and method

Abstract: A heavy-wall steel having a flange thickness of about 40 mm or more and possessing excellent strength, toughness, weldability, and seismic resistance capable of being used for structure members such as columns and beams of high-rise buildings. The heavy-wall steel has a tensile strength of about 490-690 MPa, a yield ratio of about 80% or less, and Charpy absorbed energy at 0° C. of about 27 J or more at the center in terms of thickness of the flange portion in each of the rolling direction, the direction perpendicular to the rolling direction, and the plate-thickness direction.

Weldability of commercial AL-CU-LI Alloys

Abstract: A new methodology for assessing weld solidification cracking using the Varestraint test was utilized to evaluate the susceptibility of Al-Cu-Li alloys 2090, 2094, and 2195. These alloys were found to be more susceptible to cracking than Li-free alloys 2014 and 2219. A new index, the solidification cracking temperature range, is used to quantify this susceptibility. The effect of solidification behavior and eutectic liquid film formation on crack behavior is described. (orig.)

New developments in actuator materials as reflected in magnetically controlled shape memory alloys and high-strength shape memory steels

Abstract: Shape memory alloys (SMA) are applied as actuator materials in smart structures and in fastening and pre-stressing devices. Shape memory alloys can be divided into three groups: one-way alloys, two-way alloys and magnetically controlled SMAs. The magnetically controlled SMAs recently suggested by one of the present authors are potential actuator materials for smart structures because they may provide rapid strokes with large amplitudes under precise control. The most extensively applied conventional SMAs are Ni-Ti and Cu- based alloys. Iron-based shape memory alloys, especially Fe-Mn-Si steels, are becoming more and more important in engineering applications due to their low price. The properties of Fe- Mn-Si steels have been improved by alloying, for example, with Cr, Ni and Co. Nitrogen alloying was shown to significantly improve shape memory, mechanical and corrosion properties of Fe-Mn-Si-based steels. Tensile strengths over 1500 MPa, recovery stresses of 300 MPa and recoverable strains of 4% have been attained. In fasteners made from these steels, stresses of 700 MPa were reached. The beneficial effect of nitrogen alloying on shape memory and mechanical properties is based on the decrease of stacking fault energy and increase of the strength of austenite caused by nitrogen atoms. Nitrogen alloyed Fe-Mn-Si- based steels are expected to be employed as actuator materials in pre-stressing and fastening applications in many fields of engineering. Nitrogen alloyed shape memory steels possess good manufacturing properties and weldability, and they are economical to process using conventional industrial methods.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Steel tube for air bag, with high strength and high toughness, and its production

Abstract: PROBLEM TO BE SOLVED: To provide a steel tube having a high dimensional accuracy, excellent in workability, and suitable for parts for an air bag, requiring high strength and high toughness, and its production. SOLUTION: The steel tube for an air bag, with a high strength and high toughness, has a composition consisting of 0.05-0.15% C, ≤0.50% Si, 0.30-2.00% Mn, ≤0.020% P, ≤0.020% S, ≤0.10% Al, and the balance Fe with inevitable impurities. This steel tube has high dimensional accuracy and excellent workability and weldability and can secure high strength and high toughness. Further, after tubemaking of this steel, the resultant steel tube is cold-worked into prescribed size and used in this as-cold-worked state, or the steel tube is subjected, after cold working, to annealing, normalizing, or quench-and-temper treatment, by which the steel tube having high dimensional accuracy, excellent in workability and weldability, and suitable for parts for an air bag, requiring high strength and high toughness, can be produced. COPYRIGHT: (C)1998,JPO

Weldability of 9Cr‐1Mo‐Nb, V P91 steel intended for service in the power industry

Abstract: (1996). Weldability of 9Cr‐1Mo‐Nb, V P91 steel intended for service in the power industry. Welding International: Vol. 10, No. 5, pp. 370-380.

Deformable alloys based on the Al - Mg - Se system

Abstract: Aluminum alloys with magnesium that are deformable and not strengthened by heat treatment are widely used as a structural meterial due to their good weldability, high corrosion resistance, and high ductility However, even the strongest alloys of this system, containing 5–6% Mg, have low strength characteristics For example, annealed sheets of alloy AMg6 have σb = 340 N/mm2 and σ02 = 180 N/mm2 The present work concerns the possibility of strengthening AI - Mg alloys by an additional alloying with scandium

Production method of steel pipe excellent in corrosion resistance and weldability

Abstract: A steel pipe having excellent corrosion resistance in an environment containing wet carbon dioxide and a small amount of hydrogen sulfide and having also excellent weldability is produced at a low production cost and with high productivity. The production method comprises heating to a temperature of 1,050° to 1,300° C. a slab containing, in terms of wt %, 0.01 to less than 1.2% of Si, 0.02 to 3.0% of Mn, 7.5 to 14.0% of Cr and 0.005 to 0.5% of Al, reduced C, N, P and S contents, at least one of Cu, Ni, Co, Mo and W, a balance of Fe and unavoidable impurities, and having an MC value of at least 0, finishing hot rolling within an austenite monophase temperature range, coiling the steel sheet as a hot coil having a sheet thickness of 3.0 to 25.4 mm, cooling the coil at a cooling rate of at least 0.01° C./sec to at least 500° C. to convert the steel sheet to a steel substantially consisting of martensite, reheating the steel to a temperature of 550° C. to not more than an A c1 transformation point, holding it for at least 15 minutes, cooling the steel web to a normal temperature, cutting it into a predetermined width, and welding both ends of the steel by electric resistance welding while the steel coil is continuously shaped into a cylindrical shape.

アルミクラッド鋼と鋼およびアルミニウムとのスポット溶接-インサート材を用いた鋼とアルミニウムの異種金属接合(第1報)-

Abstract: This paper deals with the resistance spot weldability of an aluminum clad steel sheet to a steel or an aluminum sheet, and the dissimilar metal joining of a steel to an aluminum sheet with an aluminum clad sheet as an intermediate layer. The clad sheet was produced by hot rolling of steel and aluminum sheets with a direct resistance heating process. The mechanical properties of the clad sheet were between those of the steel and the aluminum sheet, and the peel strength was satisfactorily high.Materials used in spot welding were a 0.8 mm-thick EDDQ steel sheet, a 1.0 mm-thick aluminum-magnesium alloy sheet and the 0.8 mm-thick clad sheet which has a thickness ratio of aluminum/steel 1.1. The spot welding of the steel sheet to the steel side of the clad sheet and the aluminum sheet to the aluminum side of the clad sheet were successful. The spot welding of the steel sheet to the aluminum sheet by using the clad sheet as intermediate layer was also successful. However, thin intermetallic compound layer was formed at the steel/aluminum interface of the clad sheet due to the spot welding thermal cycle. The suitable welding current ranged between the values suitable for steel to steel and for aluminum to aluminum.The tensile shear strength and the U-tension strength of steel-clad-aluminum joints were higher than those of steel-aluminum direct joints and close to those of aluminum-aluminum joints. These results from mechanical tests suggest that the existence of intermetallic compound layers at steel/aluminum interfaces of the clad sheets were not detrimental to the strength of the steel-clad-aluminum joints. The fracture mode of these joints varied with the welding current.

Weldable High Strength Steel Having Excellent Low Temperature Toughness

Abstract: This invention adds elements such as Cu, B, Cr, Ca, V, etc, to a low carbon-high Mn--Ni--Mo-trace Ti type steel, and allows the steel to have a tempered martensite/bainite mixed structure containing at least 60% of tempered martensite transformed from un-recrystallized austenite having a mean austenite grain size (dγ) of not greater than 10 μm as a micro-structure, or a tempered martensite structure containing at least 90% of martensite transformed from un-recrystallized austenite The present invention further stipulates a P value to the range of 19 to 40 and thus provides a ultra-high strength steel having a tensile strength of at least 950 MPa (not lower than 100 of the API standard) and excellent in low temperature toughness, HAZ toughness and field weldability in cold districts

Pearlitic rail, excellent in wear resistance and weldability, and its production

Abstract: PROBLEM TO BE SOLVED: To improve the wear resistance and weldability, required of a high- load railroad rail. SOLUTION: The railhead of a hot rolled or reheated high temp. steel rail, which has a composition containing, by weight, >0.85-1.20% C, 0.10-1.00% Si, 0.20-1.50% Mn, and 0.05-1.00% Cr, satisfying Si/4+Mn+Mn/2+Cr=0.8 to 1.8%, and containing, if necessary, one or ≥2 elements among Mo, V, Nb, Co, and B, is subjected, from a temp. in austenite region, to accelerated cooling at a rate of (1 to 10)°C/sec, to accelerated cooling at a rate of (>10 to 30)°C/sec to 75% pearlitic transformation, and then to accelerated cooling at a rate of (>10 to 30)°C/sec and controlled cooling at a rate of (1 to 10)°C/sec. By this method, the rail, in which a part between the railhead surface and a position at a depth of at least 20mm from the railhead surface has pearlitic structure and has ≥Hv320 hardness and further the difference between the hardness of the base material of rail and that of a welded joint is regulated to ≥Hv30, can be produced. COPYRIGHT: (C)1997,JPO

Surface-treated steel sheet excellent in corrosion resistance after working

Abstract: Object: to develop a material which can be improved in the resistance to corrosion caused by alcoholic fuels after working without detriment to the weldability and without any substantial cost increase. Constitution: a chromate coating is formed on Zn-X-alloy electroplated steel sheets (wherein X is at least one element selected among 3-18 wt.% Ni, 0.02-3 wt.% Co, 25-45 wt.% Mn, and 8-20 wt.% Cr). The crack density of the Zn-X-alloy coating present under the chromate coating is 1,000-150,000/mm2 in terms of the spot surrounded by the cracks, among which cracks having the maximum width of 0.5 νm or less account for at least 90 % and cracks whose depths are at least 80 % of the coating thickness account for at least 80 %.

インサート材を用いた鋼とアルミニウムの異種金属接合 （第１報） アルミクラッド鋼と鋼およびアルミニウムとのスポット溶接:インサート材を用いた鋼とアルミニウムの異種金属接合(第1報)

Abstract: This paper deals with the resistance spot weldability of an aluminum clad steel sheet to a steel or an aluminum sheet, and the dissimilar metal joining of a steel to an aluminum sheet with an aluminum clad sheet as an intermediate layer. The clad sheet was produced by hot rolling of steel and aluminum sheets with a direct resistance heating process. The mechanical properties of the clad sheet were between those of the steel and the aluminum sheet, and the peel strength was satisfactorily high.Materials used in spot welding were a 0.8 mm-thick EDDQ steel sheet, a 1.0 mm-thick aluminum-magnesium alloy sheet and the 0.8 mm-thick clad sheet which has a thickness ratio of aluminum/steel 1.1. The spot welding of the steel sheet to the steel side of the clad sheet and the aluminum sheet to the aluminum side of the clad sheet were successful. The spot welding of the steel sheet to the aluminum sheet by using the clad sheet as intermediate layer was also successful. However, thin intermetallic compound layer was formed at the steel/aluminum interface of the clad sheet due to the spot welding thermal cycle. The suitable welding current ranged between the values suitable for steel to steel and for aluminum to aluminum.The tensile shear strength and the U-tension strength of steel-clad-aluminum joints were higher than those of steel-aluminum direct joints and close to those of aluminum-aluminum joints. These results from mechanical tests suggest that the existence of intermetallic compound layers at steel/aluminum interfaces of the clad sheets were not detrimental to the strength of the steel-clad-aluminum joints. The fracture mode of these joints varied with the welding current.

Hot rolled steel plate excellent in toughness and having low yield ratio and high strength and its production

Abstract: PURPOSE: To produce a hot rolled steel plate excellent in toughness and having low yield ratio and high strength without causing the nonuniformity of material in the directions of thickness and length and the deterioration of weldability and sour resistance. CONSTITUTION: A steel, having a composition consisting of, by weight, 0.005-<0.030% C, ≤1.5% Si, ≤1.5% Mn, ≤0.020% P, ≤0.015% S, 0.005-0.10% Al, ≤0.0100% N, 0.0002-0.0100% B, either or both of ≤0.20% Ti and ≤0.25% Nb within the range satisfying the relation of (Ti+Nb/2)/C≥4, and the balance Fe with inevitable impurities, is used. Further, the metallic structure is composed of ferrite and/or bainitic ferrite, and the amount of solid-solution C in the grain is 1.0-4.0ppm. By this method, the hot rolled steel plate, excellent in toughness and having low yield ratio and high strength, can be obtained. COPYRIGHT: (C)1996,JPO

High-tensile aluminum alloy for welding excellent in stress corrosion cracking resistance

Abstract: PROBLEM TO BE SOLVED: To produce an Al alloy for welding structures having high strength, excellent in weldability and stress corrosion cracking resistance and furthermore excellent in workability. SOLUTION: This aluminum alloy has a compsn. contg., by weight, 4 to 8% Zn, 0.3 to 3.0% Mg and 0.03 to 3.0% Sc, furthermore contg. at least one kind of 0.005 to 0.2% Ti and 0.0001 to 0.08% B, moreover contg. at least one kind among 0.01 to 1.5% Mn, 0.01 to 0.6% Cr, 0.01 to 0.5% V, 0.05 to 3.0% Ni and 0.01 to 0.5% Mo or furthermore contg. one or ≥ two kinds among 0.03 to 1.0% Ag, 0.3 to 3.5% Cu, 0.01 to 0.25% Zr and 0.03 to 5.0% rare earth elements (one or ≥ two) kinds among La, Ce, Pr, Nd and Sm), and the balance aluminum with inevitable impurities. COPYRIGHT: (C)1997,JPO

Friction welding of pure tungsten to oxygen free copper with an intermediate layer

Abstract: Summary This paper describes an investigation of commercially pure tungsten friction-welded to oxygen free copper with intermediate layers of various metals to improve friction weldability. The intermediate layers used were 20–30 μm thick Ti, Al, Nb, Ni, Fe, and Ag foils. The effects of the intermediate layers on burn-off deformation behaviour and joint performance are examined. The friction welding conditions adopted were: a friction pressure of 50 MPa, forging pressure of 340 MPa, rotational speed of 40 sec−1, and forging time of 6 sec. The friction time was varied in the 1.0–10.0 sec range depending on the type of intermediate layer concerned. The burn-off rates observed during friction welding with all intermediate layers other than Ag are greater than those found without an intermediate layer. Ti, Nb, and Fe intermediate layers most notably lead to a sharp increase in burn-off rate. All intermediate layers other than Ag become finer or thinner during friction welding and are mixed with Cu to form str...