Showing papers on "Weldability published in 1990"

Weldability of aluminium-lithium alloy 2090 using laser welding

Abstract: Lithium-containing aluminium alloys are of considerable current interest in the aerospace and aircraft industries because lithium additions to aluminium improve the modulus and decrease the density compared to conventional aluminium alloys. Many such alloys are under development for aircraft applications, which usually involves mechanical fastening. While aluminium-lithium alloys are fusion weldable with gas metal arc, gas tungsten arc and electron beam processes, they suffer from problems of weld porosity, heat-tearing cracking, poor penetration and low joint efficiency. In this paper, the weldability of aluminium-lithium alloys is briefly reviewed. The weldability of commercial aluminium-lithium alloy 2090 in the peak-aged condition was studied using laser welding. The quality of the welds was evaluated through mechanical tests (hardness and tensile tests) and microscopical observations. Mechanical property data and microscopical observations of the welds on prior surface-prepared (milled) material revealed a low degree of the weld surface degradation and an absence of porosity. This coupled with the attractive joint efficiencies suggest the superiority of the laser welding to conventional arc welding of this alloy. The performance of laser-welded butt joints is rationalized.

Recent developments in the weldability of lithium-containing aluminium alloys

Abstract: The weldability of aluminium-lithium alloys is reviewed with emphasis on alloys that are being commercialized: 2090, 8090 and Weldalite™ 049. These alloys are weldable, although hotcracking susceptibility has been reported for 2090 and 8090 when welded with certain conventional filler alloys. Mechanical property data from weldments made by several techniques are emphasized. Weld-zone porosity problems, discussed at length in a 1985 review in this journal, have largely been controlled by proper weld pretreatment and gas shielding. Interest in the weldability of aluminium-lithium alloys has taken on increased significance because of their potential to reduce the weight of space launch systems, whose fabrication most often involves welding.

High strength aluminum alloy for welding excellent in stress corrosion cracking resistance

Abstract: PURPOSE: To offer the plate material excellent in formability as well as strength, stress corrosion cracking resistance and weldability by specifying the kinds and contents of the alloy components in an Al-Zn-Mg series alloy plate material. CONSTITUTION: The Al alloy contains, by weight, 4 to 7% Zn, 0.3 to 3.0% Mg, 0.03 to 0.1% Ag, 0.01 to 1% Fe and 0.05 to 0.2% Ti, furthermore contains one or more kinds among 0.01 to 1.5% Mn, 0.01 to 0.6% Cr, 0.01 to 0.25% Zr and 0.0001 to 0.08% B and the balance Al. Ag improves the stress corrosion cracking resistance and strength, but in the case of more than the upper limit, the weldability is deteriorated. Fe improves the weldability, but in the case of more than the upper limit, the toughness and workability are deteriorated. Ti improves the strength and weldability, but in the case of more than the upper limit, the toughness and workability are deteriorated. Mn, Cr, Zr and B stabilized the structure, but in the case of more than the upper limit, the toughness and workability are deteriorated. COPYRIGHT: (C)1991,JPO&Japio

Heat-resistant austenitic stainless steel

Abstract: A heat-resistant austenitic stainless steel is disclosed. This steel essentially consists of: not more than 0.06% C, 1-4% Si, 0.5-4% mn, not more than 0.035% P, not more than 0.005% S, 10-17% Ni, 14-20% Cr, 1-4% Mo, 0.01-0.5% Al, not more than 0.035% N, and balance essentially Fe, and may further contain small amounts of any of Cu, REM and B and the composition thereof is adjusted so that a limited amount of δ-ferrite appears in solidification. The steel has excellent hot salt corrosion resistance, weldability, salt errosion resistance of the weld and hot-workability.

Resistance spot weldability of comparatively thick C-Mn-Cr-Mo dual phase steel sheet.

Abstract: Welding of comparatively thick (4 mm) C-Mn-Cr-Mo dual phase steel has been carried out by resistance spot welding process. Weldability of this steel has been studied by varying the electrode force and the primary welding parameters affecting the heat input such as the effective current and weld time. The influence of these welding parameters on the morphology, microhardness and the tensile shear strength of the weldment are investigated. Optimum welding parameters producing maximum joint strength are established as electrode force of 615 kg, effective current of 6 kA and weld time of 80 cycle. Weakening of weldment caused by excess tempering of martensite at the outer region of HAZ was not observed in the range of optimum welding conditions.

Development of Low-Carbon, Copper-Strengthened HSLA Steel Plate for Naval Ship Construction

Abstract: : Modern warships designs require an increased utilization of high strength, alloy steel plate for weight reduction, stability, increased payload, and increased mobility. Naval ship structures are subjected to a complex spectrum of loads and service environments, and the structural steels and welding materials used in hull fabrication must demonstrate high fracture toughness for these extreme service conditions. The welding of HY-series high strength steels, traditionally used in Navy ship construction, requires a number of fabrication controls to prevent weld cracking, which result in high fabrication costs. The Navy initiated the HSLA steel program with a goal of reducing ship-building costs. This report describes the development and certification of Cu-strengthened HSLA steels which are weldable with reduced parameter control (particularly preheat,), and provide high strength, high toughness, and high quality weldments. HSLA-80 steel (MIL-S-24645) was certified for use in ship construction after an extensive program demonstrated that the low carbon, copper precipitation strengthened steel met the performance requirements of HY-80 steel, but was readily weldable without preheat. Lower fabrication costs and higher productivity in construction were realized. (jes)

Steel for plastics molds superior in weldability

Abstract: Disclosed is a steel for plastics molds superior in weldability. The steel consists essentially of C: 0.1 to 0.3%, Mn: 0.5 to 3.5%, Cr: 1.0 to 3.0%, Mo:0.03 to 2.0%, V:0.1 to 1.0% and S: 0.01 to 0.10%; Si: not more than 0.25%, P: not more than 0.2%, and B: not more than 0.002%; the balance being substantially Fe. The alloy composition should satisfy the following formula: BH=326.0+847.3 (C%)+18.3 (Si%) -8.6 (Mn%)-12.5 (Cr%)≦460 The steel can be welded in the process of manufacturing a plastics mold without reqiring preheating and postheating.

Austenitic stainless steel

Abstract: The invention relates to an austenitic stainless steel having a high tensile strength, a high impact strength, a good weldability and a high corrosion resistance, particularly a high resistance to pitting and crevice corrosion. The steel contains in weight-%: max 0.08 C max 1.0 Si more than 0.5 but less than 6 Mn more than 19 but not more than 28 Cr more than 17 but not more than 25 Ni more than 7 but not more than 10 Mo 0.4 - 0.7 N from traces up to 2 Cu 0 - 0.2 Ce balance essentially only iron, impurities and accessory elements in normal amounts.

Ultrahigh tensile strength cold rolled steel sheet and its manufacture

Abstract: PURPOSE: To easily obtain a ultrahigh tensile strength cold rolled steel sheet excellent in weldability and baking hardenability and suitable for forming in which spring back properties are regarded as of major importance by incorporat ing a steel with optimum amounts of Mo, V, etc., or Si, Mn and Cr without increasing the content of C and specifying its structure. CONSTITUTION: A steel contg., by weight, 0.08 to 0.20% C, 0.1 to 1.5% Si, 1.5 to 3.5% Mn, 0.15 to 0.50% Cr and 0.02 to 0.10% Al, furthermore contg. one or more kinds among 0.02 to 0.20% Mo, 0.015 to 0.150% V, 0.01 to 0.10% Ti and 0.01 to 0.10% Nb and the balance Fe is hot-rolled and is furthermore cold- rolled into a final sheet thickness, and this steel strip is subjected to continuous annealing. At this time, the steel strip is heated to (the Ac 3 point -50°C) to (the Ac 3 point +50°C) and is subjected to recrystallization annealing. After that, the steel strip is gradually cooled to the Ac 1 point and is rapidly cooled at ≤ the Ac 1 point. Then, its structure is formed into a composite one of martensite and ferrite including retained austenite, by which the steel sheet having ≥120kgf/mm 2 tensile strength, ≥14% elongation, ≥60% yield ratio and 17kg/mm 2 baking hardenability and excellent in weldability can be obtd. COPYRIGHT: (C)1991,JPO&Japio

Effect of carbon on the weldability of Fe-Mn-Al alloys

Abstract: Based on the composition of 30% Mn, 10% Al, balance Fe, Fe-Mn-Al alloys with different carbon contents and thus different ferrite contents were studied. Tensile tests and U-bend tests on the autogenous GTA welded specimen were utilized to evaluate the weldability. FN measurement, optical metallography, and SEM-EDAX were used to study the microstructural characteristics of the weld metal and the base metal heat affected zone. It was found that the carbon content has a strong influence on the amount of residual ferrite in the Fe-Mn-Al weld metals studied. After heat treatment, the amount of residual ferrite is reduced and annealing twins were found in the weld metal. Tensile strengths in excess of 900 MPa in both the longitudinal and transverse welding directions were obtained. The elongation of the butt-jointwelded specimen is substantially less than that of the base metal, especially for the fully austenitic weld metal. U-bend test results gave an indication of good weldability for the Fe-Mn-Al alloys.

Organic composite coated steel strip having improved corrosion resistance and weldability

Abstract: Organic composite coated steel strips having improved corrosion resistance, weldability and coating adherence are obtained when an organic composite layer is applied to a chromate layer on a zinc or zinc base alloy plated steel substrate. The chromate layer containing up to 70% of Cr6+ based on the total chromium weight is coated in a weight of 5 to 500 mg/m2 of Cr. The organic composite layer is formed to a dry weight of 0.2 to 3.0 g/m2 from a coating composition comprising (A) a silica sol having silica dispersed in an organic solvent with a water content of up to 3.0%, the silica having an organic deposit on its surface in an amount of up to 5.0% of C based on the total silica weight, the silica having an average particle size of 0.05 to 3.0 μm and a specific surface area of 50 to 800 m2 /g, and (B) an organic resin binder having a number average molecular weight of at least 2,000. The coated strips are suitable for use as automobile bodies by press forming.

Production of martensitic stainless steel line pipe

Abstract: PURPOSE: To produce the martensitic stainless steel line pipe having excellent corrosion resistance and weldability by subjecting a martensitic stainless steel pipe having a specific compsn. to austenitization, temper treatment and cooling treatment under specific conditions. CONSTITUTION: The martensitic stainless steel pipe which is decreased in C to <0.02%, contains, by weight%, 11 to 14% Cr, 1.2 to 4.5% Cu, 4h1% Si, ≤2% Mn, and 0.005 to 0.2% Al, decreased in the content of N to ≤0.015% an the residue thereof consisted of the balance Fe and unavoidable impurities is made into a steel pipe, and thereafter, the steel pipe is austenitized at 920 to 1100°C and is then cooled at a cooling rate above water cooling. After this steel pipe is subjected to the temper treatment at the temp. above 600°C and below Ac 1 temp., the steel pipe is cooled at the cooling rate above the air cooling, by which the martensitic stainless steel line pipe is produced. COPYRIGHT: (C)1992,JPO&Japio

High-mn nonmagnetic steel for steel bridge of linear motor car

Abstract: PURPOSE: To obtain the high-Mn nonmagnetic steel for steel bridges of linear motor cars which has a small coefft. of linear expansion, satisfies mechanical characteristics and has excellent machineability, weldability and further stress corrosion cracking resistance by specifying the compsn. consisting of C, Si, Mn, Cr, and Fe. CONSTITUTION: The steel which contains 0.01 to 0.30wt.% C, 0.05 to 2.0% Si, 20 to 28% Mn, ≤7.0% Cr, and 0.010(%)≤N(%)≤0.002Mn(%)+0.007Cr(%)+0.050%, and consists of the balance iron and unavoidable impurities and further, contains at least one kind among 0.10 to 2.0% Ni, 0.10 to 2.0% Cu, and 0.10 to 2.0% Mo, and/or at least one kind among 0.01 to 0.50% Nb, 0.01 to 2.0% V, and 0.01 to 0.50% Ti at need is used. The material for the steel bridges of the linear motor cars, which is the nonmagnetic steel having low magnetic permeability, satisfies the characteristics, such as various mechanical properties, coefft. of linear expansion, machinability, weldability, and stress corrosion cracking resistance, required for the steel bridges and has extremely good workability by rolling, is thereby obtd. COPYRIGHT: (C)1992,JPO&Japio

Manufacture of low carbon martensitic stainless steel line pipe

Abstract: PURPOSE: To manufacture a line pipe excellent in corrosion resistance and weldability by heating a low carbon martensitic stainless slab to a specified temp., executing hot rolling, thereafter subjecting it to resistance butt seam welding to make a tube and executing specified heat treatment and cooling treatment. CONSTITUTION: A martensitic stainless slab contg. ≤0.08wt.% C is heated to 1050 to 1300°C, is thereafter hot-rolled into 4.0 to 25.4mm plate thickness and is coiled at ≥600°C. Next, this hot coil is cut and is subjected to resistance seam welding while it is formed into a cylindrical shape to make a tube. This resistance welded steel pipe is subjected to hardening of executing heating to the temp. range of 950 to 1100°C for ≥1min and thereafter executing cooling at least to ≤300°C at the cooling rate of that of air cooling or above. In this way, the structure of the steel pipe is formed into a one constituted of ≥50vol.% martensite. Next, the steel pipe is reheated to the temp. of 550°C to the AC1 transformation point, is held for ≥1min, is thereafter cooled at least to ≤300°C at the cooling rate of that of air cooling or above and is tempered. In this way, a low carbon martensitic stainless steel pipe useful as a line pipe can be obtd. COPYRIGHT: (C)1992,JPO&Japio

Production of high strength steel sheet having superior formability

Abstract: PURPOSE:To obtain a high strength steel sheet reduced in C content and excellent in formability by applying pickling and cold rolling to a steel containing specific amounts of Si, Mn, and Al, subjecting the resulting steel sheet to heating and cooling under respectively specified conditions, and further subjecting the above steel sheet to holding for a time defined according to steel components and then to cooling. CONSTITUTION:A steel having a composition consisting of, by weight, 0.07-0.12% C, 0.50-2.00% Si, 1.00-2.50% Mn, 0.005-0.100% solAl, and the balance Fe with inevitable impurities is pickled and cold-rolled at 30-85% draft. Subsequently, the resulting steel sheet is heated up to a temp. of the Ac1 point or above, 700-800 deg.C, held at the above temp. for 15sec-5min, and cooled down to 200-450 deg.C at 1-200 deg.C/sec cooling rate. Successively, at 300-450 deg.C, the above steel sheet is held at an average temp. T deg.C for a time (t)sec defined according to steel composition so that the value of X given by an equation is regulated to 6-7, which is then cooled down to <=150 deg.C within 60sec. If neccessary, one or more elements among Ni, Cr, Co, and Cu are added by <=1% in total to the above steel composition. This steel sheet has satisfactory weldability, etc.

Galvanized steel sheet excellent in weldability, workability in pressing and chemical convertibility

Abstract: PURPOSE: To obtain a galvanized steel sheet excellent in chemical convertibility as well as weldability and workability in pressing by coating the surface of a galvanized steel sheet with an oxide layer essentially consisting of a specified amt. of ZnO and coating its upper layer with an oxide layer of specified amounts of Mn, P or the like. CONSTITUTION: As the amt. of ZnO, 30 to 3000mg/m 2 oxide is formed on the surface of a galvanized steel sheet. Its upper layer is coated with one or ≥ two kinds among the oxides of Mn, P, Mo, Co, Ni, Ca, W, V, etc., or boric acid by 1 to 500mg/m 2 as the amt. of metals in the oxides. If required, the oxide layer on the upper layer is furthermore incorporated with 1 to 500mg/m 2 of one or ≥ two kinds among SiO 2 , TiO 2 and Al 2 O 3 . In this way, the galvanized steel sheet excellent in weldability, workability in pressing and chemical convertibility can be obtd. The above oxide film essentially consisting of ZnO can easily be formed by bringing the galvanized steel sheet into contact with an aqueous soln. of an oxidizing agent contg. acid. Moreover, the above oxide film of Mn or the like can surely be formed by immersing the galvanized steel sheet into an aqueous soln., or spraying it with an aqueous soln. or subjecting it to cathode electrolytic treatment in an aqueous soln. COPYRIGHT: (C)1992,JPO&Japio

Manufacture of rolled aluminum alloy sheet for forming

Abstract: PURPOSE:To manufacture a rolled Al alloy sheet excellent in formability, corrosion resistance, and weldability and having high strength by subjecting an ingot of Al alloy having a specific composition in which Si and Mg are incorporated and respective contents of impurities are limited to homogenizing treatment, to rolling, and then to specific heat treatment. CONSTITUTION:A molten alloy having a composition which contains 0.6-1.2% Si, and 0.6-1.11%, Mg and also contains, as impurities, =5 deg.C/sec cooling rate. After subjected to straightening, the rolled sheet is heated up to 60-360 deg.C, held at the above temp. for a time within a shaded region B, and then cooled. The above heating and cooling are carried out at heating and cooling rates within a shaded region A. By this method, the rolled Al alloy sheet of Al-Si-Mg type for forming excellent in formability, corrosion resistance, and weldability can be obtained.

Production of high strength steel increased in toughness up to central part of plate thickness and having weldability

Abstract: PURPOSE: To obtain a high strength steel increased in toughness from the surface layer part of plate thickness to the central part, reduced in welding hardenability, and excellent in low-temp. welding crack by specifying a composition and a manufacturing process and attaining the refining of crystalline grains in respective positions of plate thickness. CONSTITUTION: A slab of a steel having a composition consisting of, by weight, 0.02-0.20% C, 0.01-0.5% Si, 0.3-1.5% Mn, 0.01-0.05% Al, ≤0.01% N, and the balance iron is subjected to heating to undergo hot rolling. In the stage of this heating, after the minimum temp. in the central part of the thickness of the steel slab reaches the Ac 3 point, the steel slab is drawn out from a heating furnace in the nonuniformly heated state where the temp. is ≤(Ac 3 point + 200°C) and the temp. difference between the surface layer part of the steel slab and the central part is 50-250°C. This steel slab is hot rolled in the temp. region where austenite is recrystallized at 10-70% reduction of area and is then hot rolled in the temp. region where austenite is not recrystallized at 20-75% reduction of area, and successively, direct hardening treatment where water quenching is started at a temp. of the Ar 3 point or above and stopped at ≤600°C is carried out. COPYRIGHT: (C)1991,JPO&Japio

Surface treated steel sheet for welded can material and method for its production

Abstract: A surface treated steel sheet having double layers consisting of a lower layer of metallic chromium and an upper layer of hydrated chromium oxide are formed on a low tin plated steel sheet in which 30 to 80% of the surface of the steel sheet is covered with plated tin and the size of the exposed steel surface units, after tinplating, is 05 to 20 mum in diameter when expressing the irregularly exposed areas as circles, and a method for production of this surface treated steel sheet which comprises; (a) electroplating with a small amount of tin under restricted conditions in order to obtain the low tin plated steel sheet described above, (b) after reflowing or without reflowing of the plated tin, formation of said double layer or formation of the metallic chromium layer followed by formation of hydrated chromium oxide under restricted conditions This surface treated steel sheet is suitable for producing a welded can body without removing the plated layer at high speed, since it is excellent in weldability, lacquer adhesion and corrosion resistance after lacquering

Low chromium asutenitic stainless steel

Abstract: PURPOSE:To obtain the stainless steel having good cold workability and weldability at the time of tube-making and having prescribed high temp. strength and corrosion resistance by regulating the limit value in each componential compsn. CONSTITUTION:A steel having the compsn. constituted of, by weight, =4XC (%). The above steel has usability enough to withstand the application to indoor distributing water pipes, automobile exhaust gas pipes, etc.

Laser welding of an advanced rapidly-solidified titanium alloy

Abstract: The present study investigated the laser weldability of the complex RS titanium alloy described above by comparatively evaluating the microstructures, mechanical properties and fracture characteristics of the base metal and the rapidly solidified weld fusion zone

Welding method and aluminum and aluminum alloy material used thereto

Abstract: PURPOSE:To obtain the Al and Al alloy materials for structural purposes having the excellent laser weldability to allow laser welding which is heretofore impossible and to decrease the thermal strains arising from welding assembly by consisting the material of the Al or Al alloy formed with an Al oxide or the hydride thereof on the surface. CONSTITUTION:The film of the Al oxide or the hydride of the Al oxide is formed preferably by an anodic oxidation treatment or bainite treatment on the surface of the Al or Al alloy material. Laser absorbability is improved in this way and a protective film for improving corrosion resistance is formed. The thickness of the above-mentioned film is preferably 0.1 to 50mum. The above- mentioned anodic oxidation treatment method is a method for forming the Al oxide film on the material surface by using oxalic acid, sulfuric acid, chromic acid, etc., as an electrolyte and executing an electrolytic treatment. The bainite treatment is a method for forming the hydride of the Al oxide on the material surface by a hot water treatment of >=70 deg.C.

Weldability of Bi-based superconductor and flame welding method

Abstract: The weldability of Bi-Pb-Sr-Ca-Cu-O superconducting ceramics has been studied in this paper. Two small bars were welded together by the conventional flame welding method. The welding region that was initially in a glass state crystallized into a polycrystalline state after a heat treatment and became zero-resistant at 106K.

Production of hot-dip galvanized steel sheet for deep drawing excellent in spot weldability

Abstract: PURPOSE: To produce a hot-dip galvanized steel sheet excellent in deep drawability and spot weldability by subjecting a cold rolled dead-soft carbon steel having a composition containing specific amounts of Al, Nb, B, etc, to annealing, to hot-dip galvanizing, and then to cooling at specific cooling velocity CONSTITUTION: A steel having a composition which contains, by weight, <00025% C, <050% Si, <15% Mn, <015% P, <002% S, 0045-010% Al, <00030% N, <003% Nb, and 00003-00015% B and in which Nb/C is regulated to 5-20 and the relations among Al, N, and B satisfy an inequality 50≤(Al/ N)+(100×B/N)≤100 is produced A slab of this steel is hot-rolled, and the resulting hot rolled plate is pickling to undergo the removal of oxide scale and cold-rolled, and the resulting cold rolled sheet is heated to a temp between 800°C and the AC 3 transformation point to undergo annealing and then subjected to hot-dip galvanizing This hot-dip galvanized steel sheet is cooled down to 600°C at 5°C/sec cooling rate COPYRIGHT: (C)1991,JPO&Japio

Galvannealed steel sheet

Abstract: PURPOSE: To reduce various restrictions at the time of producing a plated steel sheet and to improve corrosion resistance, coating suitability, and weldability by forming an alloyed plating layer consisting of Fe, Zn, and prescribed percentages of Co and Al CONSTITUTION: This galvannealed steel sheet is formed by applying an alloyed plating layer which has a composition consisting of Fe, Zn, and 001-5wt% Co or further containing, besides the above, <05wt% Al The above plated steel sheet is subjected to heating treatment after plating, by which corrosion resistance, coating suitability, and weldability can be improved COPYRIGHT: (C)1992,JPO&Japio

High strength hot rolled steel sheet having excellent workability and weldability

Abstract: PURPOSE:To manufacture the title steel sheet by subjecting a low carbon steel to hot rolling under specific conditions, satisfactorily progressing ferritic transformation, cooling the steel at a cooling speed which prevents pearite transformation and coiling it. CONSTITUTION:A slab of a low carbon steel contg., by weight, 0.10 to 0.15% C, 0.5 to 3.0% Si and 0.5 to 2.5% Mn is subjected to hot rolling, and finish rolling is ended at the temp. of (Ar3-50 deg.C) to 950 deg.C. Then, the steel is cooled to the nose temp. area of ferritic transformation of 600 to 800 deg.C at 1 to 200 deg.C/sec cooling speed, is thereafter cooled until immediately before the starting of pearlite transformation at =5% retained austenite is uniformly dispersed into a two-phase matrix of ferrite and bainite having 75mum grain size, has >=2000 strength-ductility balance (TSXEl) and >=60kgf/mm tensile strength can be obtd.

Ferritic stainless steel excellent in weldability and corrosion resistance

Abstract: PURPOSE:To improve corrosion resistance in a weld zone without deteriorating weldability and mechanical properties by specifying respective contents of Si and Mn in a steel and also regulating respective contents of C, N, Nb, and Ti. CONSTITUTION:A ferritic stainless steel has a composition which consists of, by weight, =(C+N)X8 is satisfied. Since this steel has superior formability and toughness in the weld zone as well as in the base metal and is improved in corrosion resistance in the weld zone, this steel can satisfactorily function as steel for welded structure, such as calorifier and boiler drum.