非金属材料激光连接工艺与接头性能研究进展

综述了玻璃、陶瓷、聚合物、块体金属玻璃(bulk metallic glass,BMG)等非金属之间及其与金属的激光连接工艺和接头性能的研究进展,分析了激光焊功率、焊接速度、离焦量和施加压力对接头性能的影响;对比了飞秒激光和纳秒激光对金属与玻璃接头剪切强度的影响;探究了玻璃与金属、陶瓷与金属以及陶瓷与聚合物的连接机理及其影响因素;通过添加过渡层,解决了高硼硅玻璃在可伐合金表面的开裂问题,在金属表面制备氧化膜,促进了界面结合,提高了接头性能,同时采用焊前预热和焊后缓冷热处理工艺有效降低了焊后应力,减少了裂纹的产生.     

热冲压22MnB5硼钢中频电阻点焊接头组织及力学性能研究

对2mm热冲压22MnB5硼钢试样采用中频电阻点焊连接技术,利用合适的焊接参数开展了热冲压硼钢中频电阻点焊工艺研究.对比分析了其组织及力学性能,并对试样接头进行拉剪实验、十字拉伸实验,横截面进行了微观组织、硬度分布、断裂模式分析,初步找到热冲压硼钢中频电阻点焊不同焊接规范对焊接接头力学性能的影响规律.结果表明:合理的中频电阻点焊工艺下的焊接接头具有良好的力学性能,能满足实际生产需求.     

非晶合金摩擦焊装置设计

为了增大非晶合金尺寸,设计了一种新型摩擦焊装置,用来连接毫米尺度的非晶合金棒料.该装置主要由主轴旋转单元,直线驱动单元以及参数控制单元三部分组成,分别实现工件的旋转、直线运动、摩擦焊接参数控制及采集.采用LABVIEW软件搭建了操作界面,实现焊接过程中主要参数的输入及监控采集.以Zr 55Cu 30Al 10Ni5非晶棒料为焊接对象,在不同焊接参数下进行了摩擦焊试验.结果表明,较高的转速能更快的让摩擦界面较短时间内完全进入过冷液相区,成功实现工件连接.新型摩擦焊装置能够实现非晶合金棒料的连接,达到设计要求.     

基于正交试验设计的铝/钢激光深熔点焊参数优化

通过激光匙孔点焊技术实现铝与钢的焊接. 通过正交试验方法对铝/钢进行激光匙孔点焊试验,研究时间、功率和离焦量对接头力学性能的影响程度. 结果表明,激光功率对铝/钢激光匙孔点焊接头的力学性能影响最大,离焦量次之,焊接时间影响最少,最优参数为激光功率2.85 kW、离焦量22 mm、持续时间3 s,拉伸载荷达到1470 N. 焊缝处生成锥形熔化区,界面处无裂纹,生成包含Fe₃Al、FeAl和FeAl₂等金属间化合物(IMCs),最大显微硬度(HV)达到810.     

Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel

To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by en-ergy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corro-sion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG weld-ing. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints pro-duced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.     

超高强钢焊点的S-N对数正态分布

为了研究超高强钢焊点的疲劳性能,以22Mn B5点焊结构为研究对象,采用中频伺服点焊设备对2 mm厚试件进行了焊接.利用高频疲劳试验机、激光补焊设备和光学显微镜,研究了不同焊接工艺参数下试件的S-N曲线.结果表明,焊接时间与电流参数会对高应力等级焊点的疲劳寿命产生明显影响,而其对低应力区焊点的疲劳寿命影响较小.合理的工艺参数可以有效提高焊点的疲劳寿命.利用激光工艺对焊点的微小圆周薄弱区进行补焊后,可以有效增强焊点的结构强度.     

TC4钛合金薄板储能焊接头组织与性能

采用微型储能焊机对厚度为0．2mm的TC4钛合金薄板进行了快速连接,并研究了接头组织形貌及焊接参数对接头力学性能的影响。结果表明：储能焊能够实现TC4钛合金薄板的快速凝固焊接,焊接接头由熔核和熔核向母材过渡的熔合区（线）组成。极短的焊接时间和高的冷却速率,使得熔核凝固过程具有快速凝固特征,熔核中凝固组织得到显著细化。当焊接工艺参数为电压250V、电容6600妒、电极力20N时,接头剪切强度可达601MPa。     

钢管结构K型搭接节点滞回性能参数分析

为揭示K型搭接节点隐藏焊缝焊与不焊对节点抗震性能的影响,优化了该类节点的施工工艺.按照影响钢管结构搭接节点的关键参数β、γ、τ,设计了基本试件及参数试件,采用ANSYS非线性有限元法,对钢管结构K型搭接节点隐藏焊缝焊与不焊进行了数值模拟,得到了各参数试件的滞回曲线、骨架曲线和延性性能等抗震性能指标.研究结果表明,β、γ、τ参数变化对节点承载力的影响不是十分显著,隐藏焊缝不焊接节点的滞回性能及延性优越于隐藏焊缝焊接的节点.支主管直径比β越大,节点延性越好;主管径厚比γ越大,节点延性越差.支主管厚度比τ对节点延性影响不大,尤其是τ对隐藏焊缝不焊接节点的延性基本没有影响.     

热冲压高强钢电阻点焊质量评估系统

针对热冲压高强钢电阻点焊焊后质量的评估问题,基于LabVIEW点焊设备状态监测系统提取点焊过程动态电阻信息,分析了正常焊点、未熔合焊点、飞溅焊点的动态电阻曲线特征,并提出一种五数概括阈值设定方法.结果表明:未熔合焊点与正常焊点的动态电阻曲线在上升阶段的速度、下降幅度、收尾值和有效值等特征指标上有着明显的区别.飞溅焊点的动态电阻曲线发生骤降,对曲线进行最小二乘法拟合与实际曲线相减求取差值曲线,将其均方根值作为飞溅焊点的特征指标.因此,依据焊点评价特征指标,可实现点焊质量的在线评估并取得良好效果.     

Microstructure and properties of Al-Mg-(Sc, Zr) welded joint

Mechanical properties and microstructure of Al-Mg-(Sc, Zr) welded joint prepared by manual labor melt inert gas(MIG) welding method using Al-Mg and Al-Mg-Sc weld wire as filling materials were studied comparatively. The results show that the apparent recrystallization does not happen in heat-affected zone. It proves that Al-Mg(Sc,Zr) alloy has a high capability of resistance to welding heat-soften. Using Al-Mg-Sc welding wire as filling material can obviously refine the grains of weld seam and improve its strength. The layer of small equal-axe grains in fusion area improves the joint strength between welded metal and base metal. The coefficients of welded joints when Al-Mg-Sc and Al-Mg welding wire are used as filling material are greater than 0. 90, respectively. The yield strength of welded joints with Al-Mg welding wire is only 187 MPa, one is as high as 287 MPa with A1-Mg-Sc welding wire, thus the working strength of the welded unit is greatly improved.     

超高强度钢板中频点焊力学性能

以精密超高强度淬火钢EN 10 292 TL4225为研究对象,采用先进的中频点焊连接技术,利用优化的焊接参数实现了精密高强钢同种材料之间的优质连接。对精密高强钢的点焊接头做了拉伸实验和焊点表面硬度分布实验,并利用扫描电镜对拉伸断口进行研究和分析。结果表明,采用中频点焊工艺得到的点焊接头具有良好的力学性能,能满足实际生产中的需要。     

400MPa级超细晶粒钢焊接接头的低温韧性

利用CO2+Ar气体保护焊,分别采用单道焊接和双道焊接工艺对厚度为8 mm的400 MPa级超细晶粒钢钢板进行了焊接,采用系列冲击试验方法对焊接接头的低温韧性进行了研究。试验结果表明,在焊接接头中,焊逢位置低温韧性较差。由于双道焊较小的热输入,减小了焊缝及热影响区组织粗化,其焊接接头的低温韧性好于单道焊,并使热影响区面积变小。     

Prediction and optimization of process parameter of friction stir welded AA5083-H111 aluminum alloy using response surface methodology

A systematic approach was presented to develop the empirical model for predicting the ultimate tensile strength of AA5083-H111 aluminum alloy which is widely used in ship building industry by incorporating friction stir welding (FSW) process parameters such as tool rotational speed, welding speed, and axial force. FSW was carried out considering three-factor five-level central composite rotatable design with full replications technique. Response surface methodology (RSM) was applied to developing linear regression model for establishing the relationship between the FSW process parameters and ultimate tensile strength. Analysis of variance (ANOVA) technique was used to check the adequacy of the developed model. The FSW process parameters were also optimized using response surface methodology (RSM) to maximize the ultimate tensile strength. The joint welded at a tool rotational speed of 1 000 r/min, a welding speed of 69 mm/min and an axial force of 1.33 t exhibits higher tensile strength compared with other joints.     

Q460E-Z35钢焊接传热过程的数值模拟

对Q460E-Z35钢进行了温度场和应力场的三维数值模拟。模拟结果验证了当钢材与所选的焊材匹配时,不产生裂纹的最低预热温度为150℃,提高预热温度可以更好地提高焊接材料的抗裂性。模拟结果对Q460E-Z35钢焊缝抗裂纹的能力、焊接接头的使用性能以及焊接接头抗脆性断裂的优化设计具有指导意义。     

焊接构造对T型接头超低周疲劳性能的影响

为了研究焊接细节对钢结构超低周疲劳性能的影响,以T型接头为对象,在通用有限元程序Abaqus平台上,开发基于Arlequin算法的结构多尺度计算程序. 利用多尺度算法,开展焊接接头的局部弹塑性有限元分析. 比较焊趾半径、厚钢板未熔透长度及焊趾表面凹凸对局部塑性应变履历的影响,利用Coffin-Manson模型对T型接头的超低周疲劳特性进行定性讨论. 数值计算结果表明,焊趾位置是焊接接头的超低周疲劳易损位置,厚钢板的未熔透长度对焊接部位局部塑性应变的影响不大;焊趾半径对焊趾局部塑性应变有较大的影响,增大焊趾半径可以有效提升钢结构在循环荷载下的超低周疲劳性能;焊趾表面的平整性是影响焊趾局部塑性应变履历的重要因素,尖锐的凹坑会明显降低焊接接头的超低周疲劳性能,磨平的焊趾表面可以减少局部塑性应变,提高接头的超低周疲劳强度.     

实体单元焊点模型在前纵梁碰撞仿真中的应用

为了提高碰撞仿真中汽车前纵梁焊点的模拟精度,应用LS-DYNA软件,建立了壳单元模拟母材、单个实体单元模拟焊核和热影响区的焊点模型。母材材料特性及焊点失效参数分别通过板材拉伸试验及焊点杯形拉伸试验获得。采用数值KSⅡ试验对该焊点模型在母材网格不同偏置情况下的内力进行了研究。基于经验证的纵梁有限元模型对前纵梁碰撞进行了仿...     

Microstructure and properties of Al-Mg-(Sc, Zr) welded joint

Mechanical properties and microstructure of Al-Mg-(Sc, Zr) welded joint prepared by manual labor melt inert gas(MIG) welding method using Al-Mg and Al-Mg-Sc weld wire as filling materials were studied comparatively. The results show that the apparent recrystallization does not happen in heat-affected zone. It proves that Al-Mg(Sc,Zr) alloy has a high capability of resistance to weldiing heat-soften. Using Al-Mg-Sc welding wire as filling material can obviously refine the grains of weld seam and improve its strength. The layer of small equal-axe grains in fusion area improves the joint strength between welded metal and base metal. The coefficients of welded joints when Al-Mg-Sc and Al-Mg weldiong wire are used as filling material are greater than 0.90, respectively. The yield strength of welded joints with Al-Mg welding wire is only 187 MPa, one is as 287 MPa with Al-Mg-Sc welding wire, thus the working strength of the welded unit is greatly improved. Foundation item: Project (2003AA305020) supported by the Postdoctoral Science Foundation of China; project supported by the National High Technology Research and Development Program of China     

单双丝埋弧焊工艺及接头性能比较分析

以生产中常用的16Mn钢材料为焊接母材,采用单丝交流、单丝直流埋弧焊和双丝埋弧焊工艺方法制备焊件.对不同工艺方法得到的焊接接头进行了拉伸试验,焊缝金属和焊接热影响区金属的室温冲击试验,观察了焊缝金属的显微组织,用扫描电子显微镜观察了冲击断口形貌,根据试验数据计算了不同工艺方法下的熔敷速度.比较分析结果表明:双丝埋弧焊工艺下的熔敷速度比单丝交流、单丝直流埋弧焊工艺下的熔敷速度分别提高了108%和64%,焊接速度分别提高了59%和67%,焊接工艺稳定性好,焊缝成形美观.三种工艺方法下得到的焊接接头抗拉强度和屈服强度无明显区别.单丝埋弧焊时焊缝金属的室温冲击韧度值比双丝埋弧焊时的高,单丝交流埋弧焊时焊接热影响区金属的冲击韧度值最高.     

斜拉桥正交异性钢桥面板疲劳试验研究

以板桁斜拉桥的Q500qE正交异性钢桥面板作为研究对象,采用足尺节段模型疲劳试验和数值模拟的方法,对具有宽U肋的正交异性钢桥面板关键细节的疲劳性能进行研究. 通过施加预应力的方法模拟桥面板的轴压力. 3个试验模型总计进行650万次变幅疲劳循环加载. 研究结果表明,嵌补段焊缝初始裂纹以宏观长裂纹的方式出现在腹板下缘,荷载幅越大,初始裂纹越长;宽U肋嵌补段腹板和底板的裂纹扩展可以分为4个阶段,各阶段间有明显的分界点;裂纹扩展速度与裂纹扩展长度正相关;轴压力增大了嵌补段裂纹扩展速度;对设置了焊接垫板的宽U肋嵌补段的焊缝余高进行铲除并磨平处理可以提高焊缝细节的疲劳强度. 推荐采用我国公路钢桥结构设计规范（JTG D64-2015）中110类细节疲劳强度设计宽U肋嵌补段对接接头焊缝.     

ChinZA合金TIG焊剂对焊接电弧及焊缝成型的影响

研究了ZA合金TIG焊中不同的焊剂对焊接电弧及焊缝成型的影响.结果发现:加入 KCl焊剂电弧形状变化不大； 加入LiCl焊剂电弧有收缩和“粘着”现象，电弧的宽度增加，长度减少,但阳极斑点不明显突出； 加入KF焊剂电弧有明显突出的阳极斑点产生，阴极区有所收缩；加入ZnCl2焊剂电弧的宽度和长度都有所增加，阳极斑点变小而突出；加入多组元混合焊剂电弧宽度增大，阳极斑点变小，且明显凸出，电弧长度变化不明显.电弧进入焊剂区时，焊缝表面宽度都有所减小，其中KF的减少最为明显,焊缝表面呈现金属光泽，ZnCl2最为光亮，而无焊剂区焊缝表面呈现明显的氧化现象.