共查询到19条相似文献,搜索用时 140 毫秒
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对铝含量为2%、4%(质量分数,下同)的310S耐热钢板材采用手工氩弧焊(TIG)的焊接方法进行焊接,利用光学显微镜对焊缝的显微组织进行分析,利用电子探针(EMPA)分析焊接母材的元素分布,并对焊接接头进行室温和高温(800℃)力学性能测试。结果表明:不同铝含量的310S耐热钢板材焊接后的组织均良好,都没有宏观裂纹及夹杂等缺陷;铝元素的加入,抑制了焊接热影响区晶粒的异常长大,细化了晶粒;高铝310S的焊接板材与母材一样具有优良的室温力学性能和高温力学性能,加铝310S耐热钢具有良好的焊接性能。 相似文献
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对铝含量为2%、4%(质量分数,下同)的310S耐热钢板材采用手工氩弧焊(TIG)的焊接方法进行焊接,利用光学显微镜对焊缝的显微组织进行分析,利用电子探针(EMPA)分析焊接母材的元素分布,并对焊接接头进行室温和高温(800℃)力学性能测试。结果表明:不同铝含量的310S耐热钢板材焊接后的组织均良好,都没有宏观裂纹及夹杂等缺陷;铝元素的加入,抑制了焊接热影响区晶粒的异常长大,细化了晶粒;高铝310S的焊接板材与母材一样具有优良的室温力学性能和高温力学性能,加铝310S耐热钢具有良好的焊接性能。 相似文献
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采用钨极氩弧焊和手工电弧焊焊接316L/X65双金属复合管。利用光学显微镜、能谱仪、扫描电镜、力学性能测试及电化学测试等分析手段研究了复合管焊接接头的微观结构、化学成分、力学性能及电化学腐蚀性能。结果表明,过渡层焊缝的化学成分受到稀释较小,过渡层熔合线附近出现了元素迁移,不锈钢层焊缝与母材的化学成分基本一致;扩散层为类马氏体+残留奥氏体,过渡层和不锈钢层焊缝均为奥氏体+少量铁素体;在试验参数下,焊接接头各项力学性能优良、无缺陷;覆层焊缝与母材的电化学腐蚀性能相差极小。 相似文献
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对3 mm厚304奥氏体不锈钢板进行了熔化极气体保护焊接(MIG)试验.在焊接中发现,在适当范围内提高焊接速度有利于减小焊缝和热影响区宽度,增加接头强度的稳定性;但是焊接速度过快会导致焊缝区气孔的产生,从而降低接头强度的稳定性和耐蚀性.通过控制焊接速度可以保证304奥氏体不锈钢焊接接头具有良好的力学性能和良好的耐腐蚀性能. 相似文献
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采用动电位极化曲线、电化学阻抗谱、Mott-Schottky曲线等电化学方法研究了以308 L为焊丝的304 L不锈钢焊接接头在不同氯离子含量的混凝土模拟孔隙液中腐蚀行为和电化学规律.随Cl-增加,304 L不锈钢焊接接头的三个区域(母材、焊缝和热影响区)在混凝土模拟孔隙液中的自腐蚀电位、点蚀电位及电荷转移电阻降低,钝化膜中载流子密度和焊接接头的点蚀坑数量增加.在同浓度的腐蚀溶液中,308 L的焊缝区域耐蚀性最佳,热影响区次之,304 L基体表现出低的电荷转移电阻和高的掺杂浓度使得母材的耐蚀性最差. 相似文献
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《Baosteel Technical Research》2010,(Z1):81
FSW and TIG were conducted on 316L stainless steel.Variation during microstructure and properties in joints obtained by different welding methods was studied.The results show that the effect of severe mechanical stirring and intense plastic deformation creat a fine recrystallized grain in the welding joint during FSW.As for TIG,the temperature of welding joint exceeds the melting point of welded material itself.The entire welding process belongs to the solidification of a small molten pool;and the microstructure of the joint takes on a typical casting structure.When the welding parameters were selected appropriately,the average ultimate tensile strength of FSW joints can reach 493 MPa,which is 83.6%of base metal;the average elongation is 52.1%of base metal.The average ultimate tensile strength of TIG joints is 475 MPa, which is 80.5%of base metal;the average elongation is 40.8%of base metal.The tensile test of FSW joints is superior to the TIG joints.The microhardness of FSW joint compared to base metal and TIG joint having a significant improvement,which arel95.5 HV,159.7 HV and 160.7 HV,respectively;grain refinement strengthening plays an important role in enhancing the microhardness.The electrochemical corrosion tests show that the joint of FSW 316L austenitic stainless steel has a good corrosion resistance. 相似文献
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P. Vasantharaja M. Vasudevan V. Maduraimuthu 《Transactions of the Indian Institute of Metals》2018,71(1):127-137
The present study aims at understanding the effect of various arc welding processes on the evolution of microstructure, mechanical properties, residual stresses and distortion in 9 mm thick type 316LN austenitic stainless steel weld joints. Weld joints of type 316LN stainless steel were fabricated by three different arc welding processes which were commonly employed in the nuclear industry. All the weld joints passed radiographic examination. Microstructural characterization was done using optical and scanning electron microscope. Volume fraction of δ-ferrite was lowest in the A-TIG weld joint. The A-TIG welded joint exhibited adequate strength and maximum impact toughness values in comparison to that of weld joints made by SMAW and FCAW processes. The A-TIG weld joint was found to exhibit lowest residual stresses and distortion compared to that of other welding processes. This was attributed to lower weld metal volume and hence reduced shrinkage in the A-TIG weld joint compared to that of weld joints made by FCAW and SMAW processes which involved v-groove with filler metal addition. Therefore, type 316LN stainless steel A-TIG weld joint consisting of lower δ-ferrite, adequate strength, high impact toughness, lower residual stresses and distortion was suited better for elevated temperature service compared to that of SMAW and FCAW weld joints. 相似文献
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《钢铁研究学报(英文版)》2017,(12)
The microstructure and mechanical properties of dissimilar joints of AISI 316L austenitic stainless steel and API X70 high-strength low-alloy steel were investigated.For this purpose,gas tungsten arc welding(GTAW)was used in three different heat inputs,including 0.73,0.84,and 0.97 kJ/mm.The microstructural investigations of different zones including base metals,weld metal,heat-affected zones and interfaces were performed by optical microscopy and scanning electron microscopy.The mechanical properties were measured by microhardness,tensile and impact tests.It was found that with increasing heat input,the dendrite size and inter-dendritic spacing in the weld metal increased.Also,the amount of delta ferrite in the weld metal was reduced.Therefore,tensile strength and hardness were reduced and impact test energy was increased.The investigation of the interface between AISI 316L base metal and ER316L filler metal showed that increasing the heat input increases the size of austenite grains in the fusion boundary.A transition region was formed at the interface between API X70 steel and filler metals. 相似文献
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V. Maduraimuthu M. Vasudevan V. Muthupandi A. K. Bhaduri T. Jayakumar 《Metallurgical and Materials Transactions B》2012,43(1):123-132
A novel variant of tungsten inert gas (TIG) welding called activated-TIG (A-TIG) welding, which uses a thin layer of activated
flux coating applied on the joint area prior to welding, is known to enhance the depth of penetration during autogenous TIG
welding and overcomes the limitation associated with TIG welding of modified 9Cr-1Mo steels. Therefore, it is necessary to
develop a specific activated flux for enhancing the depth of penetration during autogeneous TIG welding of modified 9Cr-1Mo
steel. In the current work, activated flux composition is optimized to achieve 6 mm depth of penetration in single-pass TIG
welding at minimum heat input possible. Then square butt weld joints are made for 6-mm-thick and 10-mm-thick plates using
the optimized flux. The effect of flux on the microstructure, mechanical properties, and residual stresses of the A-TIG weld
joint is studied by comparing it with that of the weld joints made by conventional multipass TIG welding process using matching
filler wire. Welded microstructure in the A-TIG weld joint is coarser because of the higher peak temperature in A-TIG welding
process compared with that of multipass TIG weld joint made by a conventional TIG welding process. Transverse strength properties
of the modified 9Cr-1Mo steel weld produced by A-TIG welding exceeded the minimum specified strength values of the base materials.
The average toughness values of A-TIG weld joints are lower compared with that of the base metal and multipass weld joints
due to the presence of δ-ferrite and inclusions in the weld metal caused by the flux. Compressive residual stresses are observed in the fusion zone
of A-TIG weld joint, whereas tensile residual stresses are observed in the multipass TIG weld joint. 相似文献
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Danial Kianersi Amir Mostafaei Javad Mohammadi 《Metallurgical and Materials Transactions A》2014,45(10):4423-4442
This article aims at investigating the effect of welding parameters, namely, welding current and welding time, on resistance spot welding (RSW) of the AISI 316L austenitic stainless steel sheets. The influence of welding current and welding time on the weld properties including the weld nugget diameter or fusion zone, tensile-shear load-bearing capacity of welded materials, failure modes, energy absorption, and microstructure of welded nuggets was precisely considered. Microstructural studies and mechanical properties showed that the region between interfacial to pullout mode transition and expulsion limit is defined as the optimum welding condition. Electron microscopic studies indicated different types of delta ferrite in welded nuggets including skeletal, acicular, and lathy delta ferrite morphologies as a result of nonequilibrium phases, which can be attributed to a fast cooling rate in the RSW process. These morphologies were explained based on Shaeffler, WRC-1992, and pseudo-binary phase diagrams. The optimum microstructure and mechanical properties were achieved with 8-kA welding current and 4-cycle welding time in which maximum tensile-shear load-bearing capacity or peak load of the welded materials was obtained at 8070 N, and the failure mode took place as button pullout with tearing from the base metal. Finally, fracture surface studies indicated that elongated dimples appeared on the surface as a result of ductile fracture in the sample welded in the optimum welding condition. 相似文献
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Nilesh Kumar Amit Kumar Aman Gupta Ashvin D. Gaikwad Rajesh K. Khatirkar 《Transactions of the Indian Institute of Metals》2018,71(2):361-372
In the present work, dissimilar welding between UNS S32205 duplex stainless steel (DSS) and 316L austenitic stainless steel (ASS) was performed by using gas tungsten arc welding and ER2209 filler at two different heat inputs (0.52 and 0.98 kJ/mm). Microstructures were characterized using reflected light optical microscope and scanning electron microscope. Micro-hardness and tensile properties were measured across the weld for both the heat inputs. The microstructure of the welded region was primarily austenitic (for both heat inputs) with Widmanstätten morphology. The grain size of the heat affected zone on DSS side was very large (~200 µm) for the high heat input sample with the presence of partially transformed austenite and acicular austenite. The precipitation of intermetallic phases and carbides was not observed for both the heat inputs. The proportion of ferrite in the weld metal (as measured by feritscope) was higher for the high heat input sample than the low heat input sample. During the tensile test, fracture occurred in 316L ASS base metal (because of its lower strength) in ductile manner. For high heat input welds, the impact tested sample showed the presence of fine spherical precipitates rich in Cr, Mn and Fe in the fracture surface of weld metal. 相似文献
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CO2-shielded welding experiments of newly developed, 780 MPa super-high strength heavy-duty truck crossbeam steel were conducted, and the microstructure, microhardness, mechanical properties, and impact toughness of the welded joint were studied. The evolution of the microstructure of the welded joint occurred as follows: welding seam (acicular ferrite+proeutectoid ferrite)→fusion zone (granular bainite-long strip M/A island)→coarse grain zone (granular bainite-long strip or short bar M/A island)→fine grain zone (ferrite+pearlite+blocky M/A island)→mixed grained zone (ferrite+granular bainite+blocky M/A island)→base metal (proeutectoid ferrite+granular bainite-blocky or granular M/A island). Increasing the density of the grain boundaries can effectively improve the impact toughness, and the blocky M/A island hindered crack propagation more effectively than the long strip M/A island. The new hot-rolled 780 MPa super-high strength steel had excellent weldability. The welding technology was applied under the following conditions: welding voltage was 20 to 21 V, welding current was 200 to 210 A, and the gas flow rate was 25 L/min. 相似文献
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Transformation induced plasticity (TRIP) steel exhibited high or rather high carbon equivalent (CE) because of its chemical composition, which was a particularly detrimental factor affecting weldability of steels. Thus the weldability of a TRIP steel (grade 600) containing (in mass percent, %) 0.11C-1. 19Si-1.67Mn was extensively studied. The mechanical properties and impact toughness of butt joint, the welding crack susceptibility of weld and heat affected zone (HAZ) for tee joint, control thermal severity (CTS) of the welded joint, and Y shape 60° butt joint were measured after the gas metal arc welding (GMAW) test. The tensile strength of the weld was higher than 700 MPa. Both in the fusion zone (FZ) and HAZ for butt joint, the impact toughness was much higher than 27 J, either at room temperature or at -20 ℃, indicating good low temperature impact ductility of the weld of TRIP 600 steel. In addition, welding crack susceptibility tests revealed that weldments were free of surface crack and other imperfection. All experimental results of this steel showed fairly good weldability. For application, the crossmember in automobile made of this steel exhibited excellent weldability, and fatigue and durability tests were also accomplished for crossmember assembly. 相似文献