Showing papers on "Weldability published in 1993"
TL;DR: The strengthening mechanisms of steels have been well studied widely, and are the same of the mechanisms in high strength stainless steel, e.g., grain refinement by the thermomechanical treatment, solid solution strengthening by lattice distortion through the addition of alloying element, transformation strengthening by martensite transformation, work hardening by the formation of strain induced martensites through rolling, strain aging hardening, and precipitation strengthening of intermetallic compounds which are coherent with the matrix as mentioned in this paper.
Abstract: The strengthening mechanisms of steels have been well studied widely, and are the same of the mechanisms in high strength stainless steel, e.g., grain refinement by the thermomechanical treatment, solid solution strengthening by lattice distortion through the addition of alloying element, transformation strengthening by martensite transformation, work hardening by the formation of strain induced martensite through rolling, strain aging hardening by the tempering or aging of martensite, and precipitation strengthening of intermetallic compounds which are coherent with the matrix. These strengthening mechanisms relate to the thermomechanical treatment of the steel as well as the chemical composition. Various high strength stainless steels are produced by a combination of these mechanisms, and have peculiar mechanical properties depending on the final microstructure.Recently, the need for various other properties than high strength, e.g., ductility, toughness and weldability has been recognized. Work-hardened stainless steel, for example, has greater strength than SUS301 and is used for ID blades (inner diameter blade for cutting Si single crystal), etc. The additional strength of the steel results from solid solution hardening and strain aged hardening. Martensite stainless steel and ultra microduplex stainless steel were also developed and are now in use fitting a variety of needs. The former steel has high toughness with more than 1700 N/mm2 tensile strength, and the latter has good strength and ductility but is not softened on welding.
47 citations
01 Dec 1993-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the effects of Nd:YAG laser welding parameters, including laser pulse time and power intensity, and material-dependent variables, such as absorptivity and thermophysical properties, on laser spot-weld characteristics have been studied experimentally.
Abstract: The weldabilities of AA 1100 aluminum and AISI 409 stainless steel by the pulsed Nd:YAG laser welding process have been examined experimentally and compared. The effects of Nd:YAG laser welding parameters, including laser pulse time and power intensity, and material-dependent variables, such as absorptivity and thermophysical properties, on laser spot-weld characteristics, such as weld diameter, penetration, melt area, melting ratio, porosity, and sur-face cratering, have been studied experimentally. The results of this work are reported in two parts. In Part I, the weldability of AISI 409 stainless steel by the pulse laser welding process is reported. In Part II, the weldability of A A 1100 aluminum under the same operating con-ditions is reported and compared to those of the stainless steel. When welding AISI 409 stainless steel, weld pool shapes were found to be influenced most by the power intensity of the laser beam and to a lesser extent by the pulse duration. Conduction mode welding, keyhole mode welding, and drilling were observed. Conduction mode welds were produced when power in-tensities between 0.7 and 4 GW/m2 were used. The initial transient in weld pool development occurred in the first 4 ms of the laser pulse. Following this, steady-state conditions existed and conduction mode welds with aspect ratios (depth/width) of about 0.4 were produced. Keyhole mode welds were observed at power intensities greater than 4 GW/m2. Penetration of these keyhole mode welds increased with increases in both power intensity and pulse time. The major weld defects observed in the stainless steel spot welds were cratering and large-occluded gas pores. Significant metal loss due to spatter was measured during the initial 2 ms of keyhole mode welds. With increasing power intensity, there was an increased propensity for occluded gas pores near the bottom of the keyhole mode welds.
35 citations
01 Jan 1993
28 citations
TL;DR: In this paper, the effects of fillers on the strength of vibration welded butt joints were investigated. Butylene terephthalate (PBT) and glass fibres were used as fillers and the weldability of these materials was characterized at weld frequencies of 120 and 250 Hz and weld pressures of 0.9 and 3.45 MPa.
27 citations
Patent•
23 Jul 1993
TL;DR: In this article, a process for manufacturing a medium-carbon steel plate having a graphitization of 50% or more with improved formability and weldability is disclosed, the process comprises the steps of: hot rolling a steel with a finishing temperature of 700°-900° C., the alloy composition of the steel consisting essentially of, by weight %: C: 0.20-0.70, Si: more than 0.30, Si and incidental impurities: balance, cooling the resulting hot-rolled steel plate at a cooling rate of 5°-50° C./
Abstract: A process for manufacturing a medium-carbon steel plate having a graphitization of 50% or more with improved formability and weldability is disclosed, the process comprises the steps of: hot rolling a steel with a finishing temperature of 700°-900° C., the alloy composition of the steel consisting essentially of, by weight %: C: 0.20-0.70%, Si: more than 0.20 but not more than 2.00%, Mn: 0.05-0.50%, P: not more than 0.020%, S: not more than 0.010%, sol. Al: 0.01-1.00%, B: 0.0003-0.0050%, N: 0.002-0.010%, B/N: 0.2-0.8, Cu: 0-1.00%, Ni: 0-2.00%, Ca: 0-0.010%, and Fe and incidental impurities: balance, cooling the resulting hot-rolled steel plate at a cooling rate of 5°-50° C./s, coiling the steel plate at a temperature of 400°-650° C., and optionally, cold rolling the hot-rolled steel plate with a reduction in thickness of 20-85%, and annealing the cold-rolled steel plate at a temperature of 600°- Ac 1 for 1 hour or longer.
21 citations
Journal Article•
TL;DR: In this article, the carbon equivalent and the multiplying factor are indexes for hardenability of steels and the coefficients of the elements in this carbon equivalent have been calculated from their multiplying factors reported in the literature in light of the result of a heat conduction analysis.
Abstract: The carbon equivalent and the multiplying factor are indexes for hardenability of steels. The carbon equivalent is used generally in welding and is related to the critical cooling time for the full martensite structure in the HAZ. The multiplying factor is used in heat treatment of hardenable steels and is related to the critical diameter for the full martensite. A heat conduction in a round bar has clarified that the ideal critical diameter should be expressed in a product form of alloy elements as long as the carbon equivalent is expressed in a linear combination of elements. Coefficients of the elements in the carbon equivalent have been calculated from their multiplying factors reported in the literature in light of the result of a heat conduction analysis. The coefficients of Mn, Cr, Mo and Cu are in fairly good agreement with the experimental results, while the coefficients of Si and Ni are in poor agreement.
20 citations
01 Jan 1993
20 citations
TL;DR: In this article, the electron-beam weldability, structure, and mechanical behavior of molybdenum and Mo-Re alloys produced via powder metallurgy were characterized by comparison with those produced by ingot metallomics.
Abstract: The electron-beam weldability, structure, and mechanical behavior of molybdenum and Mo-Re alloys produced via powder metallurgy were characterized by comparison with those produced by ingot metallurgy. By establishing the fabrication and processing for reducing the total oxygen of the starting materials, sound electron-beam welds of the powder metallurgy materials could be obtained. Intergranular embrittlement in the weld metal was improved by heat treatment. Carbon doping and postweld heat treatment were significantly effective to recover the strength and, therefore, the ductility. This is primarily attributed to an increase of the grain boundary cohesion due to the effective carbon segregation and precipitation. As a result, it was found that the welds of the powder metallurgy materials have good potential not only for high-performance materials but also for structural components.
17 citations
Journal Article•
TL;DR: The weldability of the modified 316 stainless steel was evaluated by the Gleeble hot ductility test and two hot cracking test methods (Varestraint and Sigmajig) as mentioned in this paper.
Abstract: The weldability of the modified 316 stainless steel was evaluated by the Gleeble hot ductility test and two hot cracking test methods (Varestraint and Sigmajig). The fusion zone and weld metal heat-affected zone (HAZ) hot cracking susceptibilities of the modified 316 stainless steel are similar to conventional fully austenitic 316 stainless steels and greater than the conventional 316 materials that have a primary ferritic solidification mode. The Gleeble hot ductility test results correlate with the base metal HAZ hot cracking results from the Varestraint test and indicate that the modified 316 materials show a considerably higher base metal HAZ hot cracking susceptibility as contrasted to nuclear grade 316 stainless steels. Varestraint test results and Sigmajig test results and Sigmajig test results for the tested materials showed good correlations. The sensitivity of the base metal to HAZ liquation cracking has been successfully predicted by using a newly developed hot ductility criterion, the ratio of ductility recovery (RDR). An excellent correlation between the Gleeble Test criterion RDR and the Varestraint Test criteria (TCL, MCL and CHL) has been found.
16 citations
Patent•
16 Apr 1993
TL;DR: In this article, the authors describe a resin-coated steel sheet having good electrocoatability and weldability, characterized in that the resin coating is formed on the layer of zinc plating or zinc alloy plating (with or without subsequent chromate treatment).
Abstract: A resin-coated steel sheet having good electrocoatability and weldability, characterized in that the resin coating is formed on the layer of zinc plating or zinc alloy plating (with or without subsequent chromate treatment) and is composed mainly of urethane resin containing (a) either colloidal silica or a silane coupling agent and (b) a phosphate of Al, Ba, Ca, Co, Fe, Mg, Mn or Zn in an amount of 0.01-35 wt % (with or without an additional organic pigment fine powder in an amount of 0.01-40 wt %).
16 citations
01 Jan 1993
TL;DR: Welding with high power CO2-lasers has proved to be an accepted technology for joining in engineering and automotive industry as mentioned in this paper, which can be used for optimization of process stability and efficiency as well as of quality of the weld seam.
Abstract: Welding with high power CO2-lasers has proved to be an accepted technology for joining in engineering and automotive industry. Combining two beams that originate from two separate lasers on a specific gantry system offers a large range of new parameters, which can be used for optimization of process stability and efficiency as well as of quality of the weld seam. With a special focusing device an independent variation of the focal conditions of each beam can be achieved. The superposition of the beams was investigated with respect to their effects upon the weldability of several materials and improvements of the welding process itself.Welding with high power CO2-lasers has proved to be an accepted technology for joining in engineering and automotive industry. Combining two beams that originate from two separate lasers on a specific gantry system offers a large range of new parameters, which can be used for optimization of process stability and efficiency as well as of quality of the weld seam. With a special focusing device an independent variation of the focal conditions of each beam can be achieved. The superposition of the beams was investigated with respect to their effects upon the weldability of several materials and improvements of the welding process itself.
Journal Article•
TL;DR: In this paper, an investigation was carried out to determine the weldability of a series of Fe 3 Al-type alloys, and the results indicated that although these alloys can be successfully welded using EB welding process, some compositions may hot crack during GTA welding.
Abstract: An investigation was carried out to determine teh weldability fo a series fo Fe 3 Al-type alloys. Autogenous welds were made on thin sheets of iron aluminide alloys using gas tungsten arc (GTA) and electron beam (EB) welding processes at different travel speeds and power levels. The results indicate that although these alloys can be successfully welded using the EB welding process, some compositions may hot crack during GTA welding. Boron and zirconium additions have been found to promote hot cracking in these alloys. Among the alloys investigated, Fe 3 Al modified with chromium, niobium and carbon (FA-129) showed the most promise for good weldability
01 Feb 1993
TL;DR: In this article, the authors proposed an aluminide composition with promising properties: FeAl alloy FA-362 (Fe-35.8% Al-0.24% B) produced by hot extrusion at 900C showed a tensile ductility of more than 10% at room temperature and a creep rupture life longer than unalloyedmore
Abstract: Objectives include adequate ductilities ([ge]10%) at ambient temperature, high-temperature strength better than stainless steels (types 304 and 316), and fabricability and weldability by conventional techniques (gas tungsten arc). The alloys should be capable of being corrosion resistant in molten nitrate salts with rates lower than other iron-base structural alloys and coating materials (such as Fe-Cr-Al alloys). Such corrosion rates should be less than 0.3 mm per year. The FeAl aluminide containing 35.8 at. % Al was selected as base composition. Preliminary studies indicate that additions of B and Zr, increase the room-temperature ductility of FeAl. Further alloying with 0.2% Mo, and/or 5% Cr, improves the creep. Our preliminary alloying effort has led to identification of the following aluminide composition with promising properties: Fe - (35 [plus minus] 2)Al - (0.3 [plus minus] 0.2)Mo - (0.2 [plus minus] 0.15)Zr - (0.3 [plus minus] 0.2)B- up to 5Cr, at. %. However, this composition is likely to be modified in future work to improve the weldability of the alloy. The FeAl alloy FA-362 (Fe-35.8% Al-0.2% Mo-0.05% Zr-0.24% B) produced by hot extrusion at 900C showed a tensile ductility of more than 10% at room temperature and a creep rupture life longer than unalloyedmore » FeAl by more than an order of magnitude at 593C at 138 MPa. Melting and processing of scaled-up heats of selected FeAl alloys are described. Forging, extruding, and hot-rolling processes for the scale-up heats are also described.« less
Patent•
26 Mar 1993
TL;DR: In this paper, a water heater was used to obtain a ferritic stainless steel for a welding clearance part and good in workability and weldability as well as in corrosion resistance.
Abstract: PURPOSE: To obtain ferritic stainless steel for a water heater excellent in the corrosion resistance on the welding clearance part and good in workability and weldability as well. CONSTITUTION: This ferritic stainless steel contains ≤0.015% C, 0.1 to 0.4% Si, ≤0.4% Mn, ≤0.04% P, ≤0.01$ S, ≤0.6% Ni, 18 to 25% Cr, 0.9 to 2.5% Mo, ≤0.02% N, 0.01 to 0.5% Al, 0.1 to 0.6% Nb and 0.05 to 0.3% Ti and contains, at need, 0.1 to 0.5% Cu and/or 0.05 to 0.3% Zr. Among each allay component, the following relationship is valid: Nb+Ti≥7(C+N)+0.15B=Cr+3(Mo+Cu)≥23.5%, P=5(Ti+Zr)+20(Al-0.01)≥1.5%, H=2.4(Cr-10)+19(Mo-0.01)+27Si≤67%, W=0.5(Si-0.1)+8(Ti-0.05)+1.5Cu+3 Zr-0..01Cr-Mo≥-1.5%. COPYRIGHT: (C)1994,JPO
TL;DR: In this paper, a crack-free weldment was obtained, which had good tensile properties up to 900 C. The tensile property and fabricability of the modified alloy, IC221W to denote improved weldability, were evaluated and found to be comparable to those of the base alloy and used to weld plates of cast IC221M.
Abstract: Most of the cast Ni[sub 3]Al alloys currently under study have marginal resistance to solidification cracking, and therefore, they have poor weldability. Crack-free welds can be made on the alloys only with difficulty, and with poor reproducibility. Based on metallographic analysis of solidification cracks in welds of one such alloy, identified as IC221M, modest composition modifications were made to the base alloy to improve solidification-cracking resistance. The tensile properties and fabricability of the modified alloy, IC221W to denote improved weldability, were evaluated and found to be comparable to those of the base alloy and used to weld plates of cast IC221M. A crack-free weldment was obtained, which had good tensile properties up to 900 C.
Patent•
11 Mar 1993
TL;DR: In this article, an area ratio of 5% for wear resistant steel with island shape martensite and remaining austenite constituted of martensites constituted of remaining Austenite by >=5% area ratio and excellent in workability, weldability and wear resistance can be obtd.
Abstract: PURPOSE:To manufacture wear resistant steel excellent in workability and weldability by subjecting low carbon steel having a specified compsn. to heat treatment under specified conditions and incorporating its matrix structure of ferrite, bainite or the like with island shape martensite at a specified area ratio. CONSTITUTION:Ferritic-pearlitic steel or bainitic steel contg., by weight, 0.05 to 0.20% C, 0.50 to 2.00% Si and 0.5 to 2.50% Mn or furthermore contg. one or more kinds among 0.05 to 1.00% Cu, 0.05 to 2.00% Ni, 0.05 to 0.5% Cr, 0.05 to O.5% Mo, 0.005 to 0.10% Nb, 0.005 to 0.10% V, 0.005 to 0.10% Ti and 3 to 20ppm B, and the balance Fe is heated between the Ac1 to the Ac3 transformation point and is thereafter cooled at the cooling rate of that of air cooling or above. The steel cong. island shape martensite constituted of martensite and remaining austenite by >=5% area ratio and excellent in workability, weldability and wear resistance can be obtd.
Patent•
03 Dec 1993
TL;DR: In this paper, a high-tough steel with a composition consisting of, by weight, 0.01-0.20% C, =30% cumulative draft, and cooling is performed to 2 deg.C to undergo rolling reduction.
Abstract: PURPOSE:To produce a high toughness steel having high toughness and low yield ratio without deteriorating weldability by subjecting a steel with specific composition to heating up to specific temp., to the rolling reduction at specific cumulative draft, and to the cooling at specific cooling velocity. CONSTITUTION:The steel has a composition consisting of, by weight, 0.01-0.20% C, =30% cumulative draft. Subsequently, cooling is performed to =2 deg.C/sec cooling rate in the central part in a plate thickness direction. Further, the steel is subjected to primary heating at <=1250 deg.C to undergo rolling reduction. After cooling, the steel is heated, as secondary heating, up to 850-1050 deg.C to undergo rolling reduction. By this method, the steel can be applied to various fields in a wide range, such as steel material for line pipe and steel material for tank.
TL;DR: In this paper, laser beam welding was applied to the joining of SiC fiber reinforced Ti-6Al-4V composite to Ti−6Al−4V alloy, and the weldability obtained for a wide bead (900 μm width) is superior to that for a narrow bead (400 mm width), the maximum joint strength of 991 MN m−2 being obtained at the optimum laser beam position for the wide bead.
Abstract: Laser beam welding was applied to the joining of SiC fibre reinforced Ti–6Al–4V composite to Ti–6Al–4V alloy. The weldability obtained for a wide bead (900 μm width) is superior to that for a narrow bead (400 μm width), the maximum joint strength of 991 MN m−2 being obtained at the optimum laser beam position for the wide bead. When the beam position was closer to the composite than the optimum range, the SiC fibres were damaged and segregation of carbon and silicon occurred near the damaged fibres. This caused a deterioration of joint strength. When the laser beam position was further from the composite than the optimum range, the joint strength was reduced by incomplete welding and/or formation of grain boundaries between the composite matrix and the Ti–6Al–4V plate. Heat treatment at 1173 K for 3·6 ks improved the joints that were welded using unfavourable laser beam positions. Therefore, heat treatment extended the range of suitable beam positions, thereby facilitating control of the laser bea...
TL;DR: The phase transition of the ferrite phase between the fusion zone and the base metal after the autogenous gas-tungsten-arc (GTA) welding process was studied in this article.
Abstract: An important area in development of any commercial alloy is the ease with which it can be welded. Six types of solidification morphologies of Fe-Mn-Al-C welds were first reported by Chou and Lee, and the mechanical properties of flux cored Fe-Mn-Al-C weld metals were tested by Makhamreh and Aidun. It was shown that the Fe-Mn-Al weld metals possessed better room-temperature strength and ductility than the conventional 310 and 316 stainless steel weld metals. However, little information has been given on the microstructural change of the Fe-Mn-Al weldment during aging. This paper presents the phase transition of the ferrite phase between the fusion zone and the base metal after the autogenous gas-tungsten-arc (GTA) welding process. The differences in transition sequences result from the microsegregation of the aluminum (Al) element during the welding process.
Patent•
17 Aug 1993
TL;DR: In this article, an austenitic steel alloy is provided having improved creep strength at high temperature by adding a limited amount of silicon to the steel alloy along with increased amounts of nitrogen and columbium, also known as niobium.
Abstract: An austenitic steel alloy is provided having improved creep strength at high temperature. The improved creep strength performance is achieved by adding a limited amount of silicon to the steel alloy along with increased amounts of nitrogen and columbium, also known as niobium. The added columbium ties up the carbon in the alloy composition to prevent sensitization promotion and premature corrosion-fatigue failures. The resulting steel alloy provides improved strength, improved carburization resistance, and maintains good weldability.
TL;DR: The authors compared the tensile, creep-rupture, and fatigue properties of GTD-222 versus FSX-414, a new cast nickel-base nozzle alloy developed by GE for use in land-based gas turbines.
Abstract: This paper summarizes the key properties of GTD-222 (Wood and Haydon, 1989), a new cast nickel-base nozzle alloy developed by GE for use in land-based gas turbines. GTD-222 is being introduced as a replacement for FSX-414 in second and third-stage nozzles of certain machines. Presented in this paper are comparisons of the tensile, creep-rupture, and fatigue properties of GTD-222 versus FSX-414. In addition, the results of a long-term thermal stability study, high-temperature oxidation, and hot corrosion evaluation as well as weldability results will be discussed.
Patent•
12 Oct 1993TL;DR: In this article, an organic composite coated steel strip with well balanced corrosion resistance, coating properties including adaptability to electrophoretic coating and water resistant secondary coating adherence, and spot weldability is provided.
Abstract: An organic composite coated steel strip having well-balanced corrosion resistance, coating properties including adaptability to electrophoretic coating and water resistant secondary coating adherence, and spot weldability is provided. The organic composite coated strip comprises a zinc or zinc base alloy plated steel substrate; a chromate layer on the substrate containing up to 70% by weight of Cr⁶⁺ based on the total chromium quantity, said chromate layer being coated in a weight of 5 to 500 mg/m² in terms of elemental chromium; and an organic composite layer on said chromate layer mainly comprising silica and an organic high molecular weight resin. In the organic composite coated steel strip, (a) silica has an average primary particle diameter of 5 to 30 nm; (b) silica is agglomerated into agglomerates of an average thickness of 0.2 to 2 µm and an average apparent diameter of 5 to 300 µm; and (c) the organic composite layer has been coated to a dry weight of 0.1 to 3 g/m². The organic composite coated steel strip of the invention has various uses including automobile bodies.
KEMA1
TL;DR: In this article, the chromium diffusion process was investigated for carbon-, low-alloy and austenitic type steels, and the quality of the diffusion coatings on low alloy steels was tested using four criteria that reflect inservice reliability of heat exchangers in coal gasifiers: thermal stability, ductility, resistance to down-time corrosion and weldability.
Patent•
30 Nov 1993
TL;DR: In this article, the authors proposed to obtain a thick-walled steel tube having high toughness, superior strength and weldability, and low yield ratio by rolling a steel of specific composition under specific conditions to form a steel plate of microstructure composed essentially of bainite.
Abstract: PURPOSE:To obtain a thick-walled steel tube having high toughness, superior strength and weldability, and low yield ratio by rolling a steel of specific composition under specific conditions to form a steel plate of microstructure composed essentially of bainite, heating this steel plate to a temp. in two phase region, and performing tubemaking. CONSTITUTION:The steel has a composition consisting of, by weight, 0.03-0.20% C, 0.01-0.50% Si, 0.5-2.0% Mn, 0.005-0.10% sol.Al, further one or >=2 kinds among 0.005-0.05% Nb, 0.01-0.10% V, and 0.005-0.10% Ti, and the balance Fe with inevitable impurities. This steel is hot rolled at >=30% cumulative draft, at a temp. between the recrystallization temp. and the Ar, point. Then, accelerated cooling is done at (0.5-30) deg.C/sec cooling rate at least down to a transformation finishing temp., by which a steel plate having a microstructure composed essentially of bainite is formed. This steel plate is reheated up to a temp. in a two phase region between the Ac1 and the Ac3 point. Then, bending into cylindrical shape is started from a temp. not lower than the Ar, point and working is finished at a temp. lower than the Ar1 point, followed by cooling at a rate not lower than air cooling rate.
Patent•
26 Mar 1993
TL;DR: In this paper, the authors propose a material and a working method by which a fire-contact surface excellent in weldability such as resistance to corrosion and crack, etc., can be attained in a build up welding of the manufacture of a valve stem made of a heat resisting steel, for a diesel engine for a marine or a power generation.
Abstract: PURPOSE:To provide a material and a working method by which a fire-contact surface excellent in weldability such as resistance to corrosion and crack, etc., can be attained in a build up welding of the manufacture of a valve stem made of a heat resisting steel, for a diesel engine for a marine or a power generation. CONSTITUTION:The composition of the build up welding metal of a fire-contact surface 3 contains 0.01 to 0.50% C, 0.1 to 2.0% Si, 35 to 55% Cr, 0.5 to 2.5% Al+Ti, and 0.01 to 0.6% N, further contains one kind or two kinds or over of <=2% Mn, <=3% V, 0.2 to 0.8% Nb, <=5% Mo, <=5% W, and <=5% Fe, and the balance Ni with inevitable impurities.
Patent•
14 May 1993
TL;DR: In this article, a manufacturing method for rim used to a wheel for automobile, particulaly an aluminum alloy-made wheel, is presented. But the method is not suitable for wheel sizes.
Abstract: PURPOSE:To provide a manufacturing method for rim used to a wheel for automobile, particulaly an aluminum alloy-made wheel. CONSTITUTION:After solution heat treatment is applied to the aluminum alloy plate material composed of by wt.%, 0.6-1.5% Si and 0.5-1.5% Mg, satisfying (Si>0.578Mg+0.4) or further <1.0% Cu, 0.15-O.45% Mn, <0.3% Cr and the balance Al with the inevitable impurities, this material is bent and flash but welding is applied to the bent end part, and after this material is finished to the rim-shape by roll-forming, heat treatment is executed at 170-200 deg.C. The weldability of the Al alloy having low Mg content is improved and the Al alloy-made rim having high strength and excellent stress corrosion crack resistance can be manufactured, and by thinning the thickness of the rim, lightening of the car is obtd.
Patent•
20 Jul 1993
TL;DR: In this paper, a hot-rolled steel sheet with a low yield ratio and high strength and excellent in spot weldability is manufactured by applying heat treatment to a hot rolled steel sheet contg. specified ratios of carbide forming elements as for the content of C under specified temp. conditions.
Abstract: PURPOSE:To manufacture a hot rolled steel sheet having a low yield ratio and high strength and, furthermore, excellent in spot weldability by executing heat treatment to a hot rolled steel sheet contg. specified ratios of carbide forming elements as for the content of C under specified temp. conditions. CONSTITUTION:A slab contg., by weight, =0.05+Ti/4+Nb/8 or, furthermore, contg. 0.3 to 1.5% Cr is subjected to hot rolling so as to complete the rolling at >=820 deg.C into a sheet, which is retained in the temp. range of 820 to 720 deg.C for >=10sec. Successively, this sheet is rapidly cooled from the temp. at >=10 deg.C/sec cooling rate and is coiled at <=500 deg.C. The objective hot rolled steel sheet having a ferritic and matensitic or/and retained austenitic structure in which fine carbides such as TiC and NbC are uniformly deposited can be obtd.
TL;DR: In this article, the use of the modified 9% Cr1% Mo steel grade (grade 91) for the manufacturing of heavy products (forgings, plates) for pressure vessels is evaluated on the following aspects: (i) possibility to produce heavy components (base material) with the required properties, (ii) conditions for welding without cracking, and (iii) availability of welding products and determination of their mechanical properties.
Patent•
28 Apr 1993
TL;DR: In this article, a stainless steel with martensite phase having a composition, which contains, by weight, <0.03% C, <1.0% Si, <2.5% Nb, 11-17% Cr, 3.5-7.5%, and 0.1-0.4% Mo and/or 0.005% Ca or further contains 0.0005-
Abstract: PURPOSE: To obtain a stainless steel material excellent in weldability as well as in toughness in a weld heat-affected zone by inhibiting the formation of delta ferrite phase in a martensitic stainless steel and regulating hydrogen content to a specific value or below. CONSTITUTION: A stainless steel with martensite phase having a composition, which contains, by weight, <0.03% C, <1.0% Si, <2.0% Mn, 11-17% Cr, 3.5-7.0% Ni, <0.02% N, and 0.001-0.05% Al and/or 0.0005-0.005% Ca or further contains 0.1-0.4% Mo and/or 0.01-0.5% Nb and where Nieq represented by equation I and Creq represented by equation II satisfy inequalities III, IV, and free from ferrite phase is used. This steel is hot-rolled, hardened, cooled down to ≤200°C, and successively held at 400-650°C for a time Ht represented by inequality V [where (t) is a figure showing the thickness of the steel material in millimeter], by which H 2 content is regulated to ≤0.0005%. COPYRIGHT: (C)1994,JPO
01 Jan 1993
TL;DR: In this article, a survey of weldability problems in recently developed high strength steels is presented, including developments in ultra-high strength and highly alloyed steels such as duplex stainless steels, as well as the influence of some of the newer welding processes such as electron beam and laser welding.
Abstract: The article summarises the weldability problems which might still be encountered in recently developed high strength steels. The survey excludes developments in ultra-high strength and highly alloyed steels such as duplex stainless steels, as well as the influence of some of the newer welding processes such as electron beam and laser welding. It should be emphasised that not all the potential problems are directly due to the steel; consumables also have had to be modified to meet the increasing toughness and strength requirements. Moreover, the improved inspection techniques now being applied almost certainly ensure that fine tight crack are more readily discovered and rectified during fabrication than would have been the case a few years ago.