05CuPCrNi钢等离子弧焊焊接接头的组织与力学性能

 为了研究等离子弧焊在焊接薄板耐候钢时的优越性,对2 mm厚 05CuPCrNi耐大气腐蚀钢分别进行等离子弧焊与MAG焊(熔化极活性气体保护电弧焊)对接焊接,然后对焊接接头分别进行拉伸、弯曲、金相、硬度等试验,通过与MAG焊焊接接头的组织与力学性能对比,结果表明,与MAG焊相比,等离子弧焊时05CuPCrNi耐大气腐蚀钢焊接接头强度相对提高约6%,焊接接头组织为更均匀且细小的铁素体＋珠光体,并无MAG焊中出现的粗大块状铁素体及贝氏体,焊接热影响区较小,焊接接头弯曲性能良好,硬度值及硬度分布情况与MAG相近且无软化现象。     

Ti-6Ta合金封头的研制

设计了3种方案对新型α型Ti-6Ta合金板材进行封头冲压成形试验,在冲压的封头不同部位取样进行压扁、拉伸、硬度、金相等相关检测和分析。结果表明:Ti-6Ta合金封头不适合采用冷冲压成形法成形;在Ti-6Ta合金板材表面涂敷高温防氧化涂层,采用315 t四柱油压机,在680~700℃温度下进行热冲压成形,能够得到表面质量良好的规格为Φ219 mm×7.42 mm的Ti-6Ta合金封头;封头的组织形貌与原始板材相比无明显变化,其压扁工艺性能合格,强度及硬度与母材基本相当,可以满足Ti-6Ta合金承压设备的制造要求。     

纯镍N6填丝等离子焊接工艺及接头组织性能的研究

试验采用等离子弧焊设备对工业纯镍N6板材进行填充焊丝等离子焊接工艺试验。借助光学显微镜(OM)、扫描电镜(SEM)、能谱分析(EDS)、X射线衍射仪(XRD)和显微硬度计等手段分析了焊接接头的微观组织和力学性能。结果表明:采用合理的焊接工艺参数可以得到成形良好的焊缝,填丝焊接接头抗拉强度为333 MPa,其抗拉强度达到母材强度的97.6%,不填丝焊接接头抗拉强度为240 MPa,达到母材强度的70.5%;母材为均匀细小的等轴晶,填丝接头焊缝处呈树枝状结晶且晶粒粗大,热影响区靠近熔池部分的晶粒过热长大,靠近母材部分为均匀细小的等轴晶;填丝接头基体为γ-Ni组织,同时存在γ'(Ni3(Al,Ti)C)强化相,填丝接头拉伸断口表现为韧-脆混合断裂,焊接接头硬度最低值出现在热影响区;与母材相比,不填丝接头焊缝区与热影响区晶粒粗大,其基体组织为单相奥氏体,不填丝接头拉伸断口表现为脆性断裂,硬度最低值出现在接头热影响区。     

细晶Q345低合金高强钢焊接接头组织性能研究

采用埋弧自动焊法对30 mm细晶Q345C低合金高强钢进行焊接,用金相显微镜观察焊接接头微观组织,并检验接头拉伸、弯曲及冲击性能。结果表明,细晶Q345母材由晶粒细小的铁素体和珠光体构成,焊接接头焊缝金属与母材强度相似。焊缝外观平整、组织均匀,焊缝和热影响区均具有良好的冲击韧性,焊接接头可以满足使用要求。     

6061铝合金搅拌摩擦焊接头组织与性能研究

采用搅拌摩擦焊方法(FSW)对6 mm厚的6061-T4铝合金板材进行对接,焊后利用光学显微镜(OM)和扫描电镜(SEM)分析、对比了焊接接头和母材的显微组织和断口形貌特征,并测试了其室温拉伸性能和显微硬度。实验结果表明:选择了适合于6061-T4铝合金板材搅拌摩擦焊的工艺参数:焊接时搅拌头旋转速度为1200 r.min-1,工件的进给速度为300 mm.min-1,在此参数下获得了与母材等强度、韧性接近于母材的焊接接头,为此种合金应用于汽车关键零部件提供了可靠的工艺方法。FSW板材接头焊核区的组织和性能明显优于其他区,热影响区是接头最薄弱的部分,焊核区的硬度最高,而热影响区的硬度最低,焊缝金属发生回复再结晶使晶粒细化。断口分析表明,断裂发生在热影响区,由于搅拌头的旋转运动和热量的累积,该区存在晶粒长大、组织粗化现象。对工艺参数的优化实验表明,搅拌头旋转速度与焊接速度对接头性能的影响存在一定的适配关系,通过工艺参数的调整可以有效地控制热影响区的焊缝组织和改善焊接接头的性能。细晶强化是搅拌摩擦焊接头强度与韧性提高的主要原因。     

不同焊速下7×××系铝合金FSW接头组织及性能研究

采用金相、扫描、显微硬度测试、拉伸等试验手段,研究了转速1 600 r/min,焊速600 mm/min、900 mm/min以及1 200 mm/min下7046-T6铝合金薄板搅拌摩擦焊接头的组织与性能。试验结果表明:焊核区的晶粒细小均匀,600 mm/min焊速下焊核区的晶粒较为粗大。受热循环的作用,热影响区晶粒呈现一定程度的粗化长大。热机影响区和焊核区的过渡区的最低硬度为108 HV。当焊接速度为900 mm/min时,焊接效果较好,焊接接头的强度为350.3 MPa,达到母材抗拉强度500 MPa的70.1%。     

TIG重熔对6005A-T6铝合金焊接接头组织及性能的影响

针对铝合金焊接接头缺陷TIG重熔修复,采用6005A-T6铝合金作为母材,先采用MIG焊对母材进行焊接,焊后采用无脉冲TIG焊对焊趾处进行重熔,有无脉冲TIG焊对焊缝处进行重熔,对重熔前后的焊接试验件进行金相显微组织形貌及性能对比分析.结果表明,重熔后热影响区宽度明显大于重熔前,组织晶粒更加粗大,弥散相分布更加均匀;硬...     

TC4钛合金TIG焊接头组织及缺陷分析

针对20 mm厚钛合金开展了TIG焊接工艺试验,采用两种不同的焊接热输入,从组织、性能及焊接缺陷等方面对接头进行了研究。结果表明:接头焊缝区的马氏体较熔合区及热影响区的马氏体分布更加弥散,热影响区马氏体的数量更少且更为细小;焊缝晶粒尺寸随着焊接热输入的增大而增大,晶粒内部的马氏体尺寸也越大且分布越弥散;焊接速度过快是导致气孔缺陷的主要原因,也是严重降低接头力学性能的重要原因。应严格控制焊接热输入,防止接头晶粒粗大,避免产生异常组织和裂纹等缺陷。     

高Ta钛合金在沸腾硝酸中的腐蚀行为

对高Ta含量钛合金Ti-32Ta在8 mol/L沸腾硝酸溶液中进行了全浸腐蚀实验,研究了Ti-32Ta合金在沸腾硝酸中的腐蚀行为。采用扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线衍射光电子能谱(XPS)等分析方法对钛合金腐蚀表面的钝化膜进行了成分、组织结构及合金价态分析。结果表明:Ti-32Ta合金在沸腾硝酸溶液中呈现均匀腐蚀行为,在介质中通入一定流量的新鲜空气对合金稳定腐蚀阶段的腐蚀速率影响不大。与Ti-6Ta合金相比,Ti-32Ta合金腐蚀后形成的钝化膜更薄更致密,耐蚀性能更好。两种合金腐蚀钝化膜中Ti和Ta的价态组成相同,Ti-32Ta合金腐蚀表面Ta及Ta2O5的含量高于Ti-6Ta合金腐蚀表面。     

Ti-Ta合金在硝酸中电化学腐蚀研究

以8 mol/L硝酸溶液为腐蚀介质,对Ti-6Ta和Ti-32Ta合金进行极化曲线和交流阻抗谱测试,并与TA2纯钛进行对比,研究不同Ta含量钛合金的电化学性能差异。结果表明,加入6%的Ta元素后,合金的腐蚀电流密度比TA2纯钛降低了近一半;加入了32%的Ta元素后,合金的自腐蚀电位提高,腐蚀电流密度比TA2纯钛降低了66%;Ti-6Ta和Ti-32Ta合金腐蚀后表面氧化膜均为单层结构;添加Ta元素可以极大地提高钛合金的电荷转移电阻,使相位角升高、变宽,增强耐腐蚀性能。     

耐火耐候钢焊接性能及焊接材料的研究

重点介绍了武钢技术中心高层办公大楼用WGJ510C2耐火耐候钢(14 mm 、25 mm)2种规格钢板与WQ-1埋弧焊丝匹配试验研究.按照工程提出的焊接技术条件,对武钢二热轧生产的WGJ510C2钢进行了埋弧焊对接性能试验,内容包括接头常规力学性能试验、高温拉伸性能试验、金相组织与硬度试验、电化学腐蚀性能试验.试验结果表明,采用WQ-1焊丝加CHF101焊剂匹配焊接WGJ510C2钢2种规格试板,接头常温拉伸强度和高温拉伸强度均满足WGJ510C2钢技术条件要求.焊缝、熔合线和热影响区低温冲击功大于140 J,接头各区电化学腐蚀电位相近,具有优良耐腐蚀性能,焊接接头综合性能指标完全满足高层建筑用钢焊接技术要求.     

船用热轧钢板焊接性能研究

建立了热轧钢板焊接热影响区（HAZ）的连续冷却转变曲线（焊接CCT曲线）,以研究船用热轧钢板的焊接性能。根据所建立的焊接CCT曲线,选择了合理的焊接工艺对10mm厚的船用热轧钢板进行了手工电弧焊,并对焊后的焊接接头进行了宏观检验和X射线探伤、力学性能试验及冲击试验。借助金相显微镜和扫描电镜分析了CCT图中不同冷速条件下的显微组织和焊接接头的显微组织以及冲击断口形貌。试验结果表明：根据建立的焊接CCT曲线,所选择的手工电弧焊的焊接工艺是合理的,焊缝质量良好,焊接接头具有良好的综合性能。     

浓硫酸中904L不锈钢焊接接头的耐蚀性能

采用动电位极化曲线和电化学阻抗谱研究了904L不锈钢基体和焊接区在浓硫酸溶液中的腐蚀行为,并简要分析其腐蚀机理.实验结果表明:焊接区和基材的阴极极化曲线均为氢还原反应过程,而阳极极化曲线则有较大的差异.焊接区相对于基材,其自腐蚀电位降低且阳极电流增大,焊接对阳极反应起促进作用.904L不锈钢基体和焊接区的腐蚀主要由电化学反应步骤控制,两者的Nyquist图特征相似,均由单一的容抗弧构成,有一个时间常数.基体的耐蚀性能优于焊接区.      

Microstructural and Mechanical Characterization of as Weld and Aged Conditions of AA2219 Aluminium Alloy by Gas Tungsten Arc Welding Process

In this article, Welding of AA2219 aluminium alloy using Gas tungsten arc welding process (GTAW) and evaluation of metallurgical, mechanical and corrosion properties of the joints are discussed. The weld samples were subjected to ageing process at the temperature range of 195°C for a period of 5 h to improve the properties. AA2219 aluminium plates of thickness of 25 mm were welded using gas tungsten arc welding (GTAW) process in double V butt joint configuration. The input parameters considered in this work are welding current, voltage and welding speed. Tensile strength and hardness were measured as performance characteristics. The variation in the properties were justified with the help of microstructures. The same procedures were repeated for post weld heat treated samples and a comparison was made between as weld condition and age treated conditions. The post weld heat samples had better tensile strength and hardness values on comparing with the as weld samples. Fracture surface obtained from the tensile tested specimen revealed ductile mode of failure.     

Ti35合金焊接接头在高温硝酸中的腐蚀性能研究

以沸腾的核乏燃料后处理模拟料液及空白硝酸溶液为腐蚀液,研究了Ti35合金焊接接头的耐腐蚀性能。在模拟料液中对Ti35合金熔敷金属及焊接热模拟样进行全浸腐蚀实验,间接评价了焊接接头熔区及热影响区的耐腐蚀性能。结果表明:Ti35合金焊接接头在沸腾空白硝酸溶液及模拟料液中均具有良好的均匀腐蚀性能,焊缝熔区及热影响区的腐蚀速率大于焊接接头的腐蚀速率,焊接接头的腐蚀对焊接应力的敏感性不高;在沸腾空白硝酸介质中,硝酸浓度对焊接接头的耐蚀性能有较大的影响,随硝酸浓度的提高,焊接接头的耐蚀性能有所下降;硝酸溶液中氧化性金属阳离子对Ti35合金的焊接接头具有缓蚀作用。     

7003铝合金TIG焊焊接接头的组织与性能

采用显微硬度及电导率测试,剥落腐蚀及电化学腐蚀试验,光学显微镜(OM)及透射电镜(TEM),研究经ER5356焊丝钨极氩弧焊(TIG)的7003铝合金型材焊接接头各部分的微观组织与性能。结果表明:在离焊缝中心30 mm左右的热影响区位置形成硬度较低的软化区,这是由于η′(Mg Zn2)相的长大粗化;焊接接头的耐蚀性依次为焊缝区过时效区母材区淬火区,其原因是淬火区的晶界析出相连续分布,形成连续阳极腐蚀通道,增大了应力腐蚀及剥落腐蚀倾向,使得腐蚀性能很差;而过时效区和母材区的晶界析出相不连续,耐蚀性较好。     

装甲车用7A52铝合金焊接性研究

针对兵器工业用7A52铝合金,从焊接工艺参数、焊后无损检测,以及破坏性实验力学性能、弯曲性能、宏观检测、焊接接头显微硬度等方面进行试验研究。结果表明,7A52铝合金焊接性能良好,接头拉伸、弯曲性能较好,抗拉强度达到274.8MPa,接头硬度曲线分布表明强度最低区域为焊缝。     

Investigation of the Microstructural,Mechanical and Corrosion Properties of Grade A Ship Steel-Duplex Stainless Steel Composites Produced <Emphasis Type="Italic">via</Emphasis> Explosive Welding

Grade A ship-building steel-AISI 2304 duplex stainless steel composite plates were manufactured via explosive welding. The AISI 2304 plates were used to clad the Grade A plates. Optical microscopy studies were conducted on the joining interface for characterization of the manufactured composite plates. Notch impact, tensile-shear, microhardness, bending and twisting tests were carried out to determine the mechanical properties of the composites. In addition, the surfaces of fractured samples were examined by scanning electron microscopy (SEM), and neutral salt spray (NSS) and potentiodynamic polarization tests were performed to examine corrosion behavior. Near the explosion zone, the interface was completely flat, but became wavy as the distance from the explosion zone increased. The notch impact tests indicated that the impact strength of the composites decreased with increasing distance from the explosion zone. The SEM studies detected brittle behavior below the impact transition temperature and ductile behavior above this temperature. Microhardness tests revealed that the hardness values increased with increasing distance from the explosion zone and mechanical tests showed that no visible cracking or separation had occurred on the joining interface. The NSS and potentiodynamic polarization tests determined that the AISI 2304 exhibited higher corrosion resistance than the Grade A steel.     

Comparison of microstructure and properties between joints of FSW and TIG 316L austenitic stainless steel

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.