镁合金焊接方法的研究进展

综述了钨极氩弧焊、电子束焊、激光焊、搅拌摩擦焊等不同焊接方法对镁合金焊接接头组织和力学性能的影响,以及焊接过程中出现的主要问题。针对镁合金的焊接特点,提出了提高其焊接接头力学性能的有效方法,并对其焊接技术的研究方向作了展望。     

高氮钢电子束焊接接头组织与性能分析

高氮钢焊接技术的研究是高氮钢研制和应用的关键技术之一。采用真空电子束焊接方法,对4 mm厚的高氮钢进行了焊接,研究了焊接接头的组织和力学性能。研究结果表明高氮钢电子束焊接焊缝和热影响区的组织为奥氏体组织,当焊接束流为20 m A、焊接速度为6.5 mm/s时,接头抗拉强度最大为1 010 MPa,达到母材强度的92.7%。高氮钢电子束焊焊缝中氮逸失较少,氮含量下降不多,由0.74%下降到0.64%。     

硬质合金与碳钢电子束对接焊接头的显微组织

选用YG30硬质合金与45钢进行电子束对接焊复合试验，用扫描电镜、波长分散X射线谱仪对焊接接头显微组织进行了分析。结果表明：当电子束电流小、焊接速度慢时，焊接接头易形成有害的η相，η相分布于YG30／焊缝界面区域，并聚集长大，η相层厚度约10μm；焊接过程中硬质合金脱碳和铁向硬质合金迁移是叩相形成的主要原因。     

焊后热处理对30CrMnSiNi2A钢电子束焊接件疲劳行为的影响

电子束局部热处理是一种新型的热处理方式，探讨其对电子束焊接接头组织和疲劳性能的影响规律具有十分重要的实际意义。文中采用CT(紧凑拉伸)试样，对30CrMnSiNi2A钢电子束焊接后焊态、焊后炉内整体热处理和电子束局部热处理三种焊接接头焊缝与母材的疲劳裂纹扩展速率进行试验研究；并测定上述两个部位的门槛值。结合金相组织分析，讨论焊后热处理对接头疲劳行为的影响。试验结果表明，电子束局部热处理和整体热处理都能够在一定程度上改善焊接接头的组织和近门槛值处抗疲劳裂纹扩展的能力。由于电子束局部热处理具有方便、省时、节省能源和提高生产率的优点，因而具有较大的应用潜力和研究价值。     

SA-312TP316H不锈钢管埋弧焊接试验

采用手工氩弧焊封底、焊条电弧焊过渡以及埋弧焊填充盖面的方法,对SA-312TP316同种钢焊接接头的微观组织和常规力学性能进行探索尝试。在合格区取样做性能和金相试验,发现弯曲试样中出现微小裂纹,接头微观组织也存在裂纹。结果表明,热输入较高条件下的焊接接头易出现夹渣和未熔合等缺陷。     

离心压缩机叶轮补焊工艺研究及应用

针对压缩机叶轮在热处理后出现的裂纹缺陷,采用手工氩弧焊工艺进行补焊。通过与手工电弧焊补焊工艺的力学性能和显微组织进行对比分析,发现焊接接头具有良好的力学性能,接头强度满足设计要求,并且避免了传统手工电弧焊工艺补焊造成的飞溅、弧坑裂纹、气孔等缺陷,提高了产品一次性补焊合格率,完善了低合金高强钢焊接叶轮制造工艺规范。对某大型压缩机叶轮进行实际补焊应用,叶轮经过超转试验后,表面检测合格,完善了低合金高强钢焊接压缩机叶轮的制造技术。     

TA15大厚度电子束焊接头组织及性能分析

通过对TA15大厚度钛合金材料的高压电子束焊工艺进行焊接试验,观察和分析了焊接接头的宏观组织形貌和微观组织特征,测试了接头的力学性能和接头硬度分布。结果表明:TA15大厚度钛合金高压电子束焊缝区、热影响区和母材区的微观组织差别明显;焊缝抗拉强度略高于母材,但塑性低于母材;接头焊缝区显微硬度值高于母材区。     

45钢/W8Co3N高速钢刀具的摩擦焊接研究

对 45钢 /W8Co3N高速钢刀具的摩擦焊接工艺及焊接效果进行了试验研究 ,结果表明 ,采用优化的摩擦焊接工艺参数及合理的焊后热处理工艺可获得具有良好显微组织和力学性能的焊接接头。     

不同焊接热输入量对焊缝热影响区组织和性能的影响分析

本文对Q390E钢，采用直径5mm和2mm两种焊丝，采用不同焊接热输入量进行埋弧自动焊，焊接接头热影响区显微组织和力学性能进行试验分析。试验结果表明，细焊丝埋弧自动焊，由于热输入量较小，高温停留时间短，热影响区过热程度较轻，奥氏体晶粒长大不严重，所以并没有形成粗大的魏氏组织铁素体；相反，使用粗焊丝进行焊接的接头，焊接热输入量大，在过热区产生了大量的粗大魏氏组织铁素体，使接头力学性能变差。     

补焊对30CrMnSiA高强钢焊接接头力学性能的影响

以30CrMnSiA高强钢原始焊接接头和一次补焊接头为研究对象,通过拉伸试验、疲劳试验及显微组织分析等方法研究了补焊对其焊接接头力学性能的影响。结果表明:经过补焊后,30CrMnSiA高强钢焊接接头的力学性能略微降低;热影响区是接头拉伸性能的薄弱部位,而焊趾处是接头疲劳性能的薄弱部位;补焊对焊缝附近的显微组织无明显影响。     

Evaluation on microstructure and mechanical properties of high-strength low-alloy steel joints with oscillating arc narrow gap GMA welding

Abstract with the purpose of improving weld joint quality and productivity, the oscillating arc narrow gap gas metal arc (GMA) welding was employed in welding quenched and tempered high-strength low-alloy thick steel. The microstructure and mechanical properties of weld joints were evaluated, namely micro-hardness, tensile strength, and low-temperature impact toughness. The test results indicated that mechanical properties of weld joints with oscillating arc narrow gap GMA welding were excellent and found to meet stipulated requirements. Oscillating arc narrow gap GMA welding is a promising process for welding quenched and tempered HSLA thick steels due to the low energy input and narrow square-butt groove.     

实芯焊丝焊接Q450NQR1耐候钢焊接接头力学性能的研究

通过室温拉伸和硬度及分析等方式,对Q450NQR1耐候钢混合气体保护焊焊接接头的力学性能进行了研究,试验结果表明:CHW-55CNH实芯焊丝焊接时,可以获得拉伸性能均良好的焊接接头,焊缝区硬度较均匀,焊缝的硬度在170～220 HV之间。     

Effect of welding processes on tensile properties of AA6061 aluminium alloy joints

The present investigation is aimed at to study the effect of welding processes such as GTAW, GMAW and FSW on mechanical properties of AA6061 aluminium alloy. The preferred welding processes of these alloys are frequently gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) due to their comparatively easier applicability and better economy. In this alloy, the weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often causes inferior weld mechanical properties and poor resistance to hot cracking. Friction stir welding (FSW) is a solid phase welding technique developed primarily for welding metals and alloys that heretofore had been difficult to weld using more traditional fusion techniques. Rolled plates of 6 mm thickness have been used as the base material for preparing single pass butt welded joints. The filler metal used for joining the plates is AA4043 (Al-5Si (wt%)) grade aluminium alloy. In the present work, tensile properties, micro hardness, microstructure and fracture surface morphology of the GMAW, GTAW and FSW joints have been evaluated, and the results are compared. From this investigation, it is found that FSW joints of AA6061 aluminium alloy showed superior mechanical properties compared with GTAW and GMAW joints, and this is mainly due to the formation of very fine, equiaxed microstructure in the weld zone.     

TP304不锈钢钢管环焊缝的A-TIG焊接研究

A-TIG焊接技术是基于TIG焊的焊接新工艺,具有大幅增加焊缝熔深、提高焊接生产率,降低成本等优点。本研究采用A-TIG焊接技术对TP304不锈钢50mm×6mm的管子进行全位置焊接,对得到的焊接接头进行射线探伤、显微组织分析以及力学性能测试,结果表明,接头的显微组织优于普通TIG焊接接头、接头质量和力学性能均达到标准要求。     

A new thermal error modeling method for CNC machine tools

Shape memory superelastic alloys as NiTi have mechanical properties and biocompatibility characteristics quite interesting for a set of industries, amongst which is the medical industry. They find applications in tools and devices where frequently joining between them and to other alloys as austenitic stainless steel is required. However, permanent joining of NiTi to stainless steel is problematic due to the formation of Fe–Ti intermetallics. Pulsed laser welding was studied to join thin foils of NiTi in similar and dissimilar joints to stainless steel. Joining NiTi to NiTi was succeeded with no weld defects. When joining NiTi to stainless steel, it was found that the material impinged by the laser determined the weld pool shape and structure, and it was better when the stainless steel foil was placed below the laser, because nickel enrichment of the weld pool was found to minimise cracking. The factors controlling the weld pool composition and, consequently, the quality of the weld were investigated and discussed.     

Virgo104 铸钢及焊接接头力学性能研究

对Virgo104钢的力学性能进行了检验,并研究了与之匹配的两种气保焊焊丝及一种焊条的焊接接头力学性能.试验结果表明,Virgo104钢中心与表面的力学性能基本一致,具有良好的强度与塑性匹配,而且具有优良的低温冲击韧度,特别是其高的Wp/Wi(约3.0)及高的侧向膨胀率(约15%),表明该钢具有优良的抗脆性断裂性能.焊缝金属及焊接接头具有良好的力学性能,其中HS367L焊丝的焊缝金属,在焊态下具有较高的塑性,预示出较高的抗焊接裂纹性能.     

CO2激光焊接接头性能的试验分析

采用同轴和侧吹保护气体控制等离子的方法,对车身专用高强度镀锌钢板的CO2激光焊接接头的性能进行了大量的焊接试验研究,并对焊缝进行显微组织分析和相关的机械性能检测.研究激光焊接高强度镀锌钢板的工艺参数对焊接接头的抗拉强度、屈服强度和延伸率等机械性能指标的影响规律,优化了激光焊接的工艺参数.试验表明随着激光焊接过程中输入线能量的增加,焊缝区的硬度值逐渐下降,拉伸试件断裂的区域、断口韧窝大小及分布情况各不同,且焊缝的拉伸裂纹均向母材扩展,说明激光深熔焊接可以有效地避免高强度镀锌钢板焊接接头的软化.     

20#钢管全位置A-TIG焊接接头组织及性能的研究

采用A-TIG焊接技术对20#钢Ф57mm×5mm的管子进行全位置焊接,对得到的焊接接头进行射线探伤和力学性能测试,结果表明,接头质量均达到标准要求,接头的显微组织优于普通TIG焊接接头。A-TIG这一新型高效的焊接技术对于管子焊接安装、提高效率、降低成本具有极大的工程意义。     

Domex700MC低合金高强钢药芯焊丝CO2气体保护焊焊接接头的组织与性能

用药芯焊丝CO2气体保护焊焊接Domex700MC低合金高强钢,用光学显微镜、硬度计和冲击试验机等对焊接接头的显微组织和力学性能进行了分析。结果表明：焊缝金属晶粒细小且分布均匀,有较多针状铁素体,但熔合区组织比较粗大,使熔合区附近塑性降低,为焊接接头的薄弱部位;焊缝金属显微硬度较高,为315HV,而在热影响区为225HV,出现软化现象;焊接接头力学性能优良,具有较高的抗拉强度（630．94MPa）和冲击功（135．34J）。     

Experimental investigation of the effect of vibration on mechanical properties of 304 stainless steel welded parts

Some of the problems that occur during the welding process include the creation of coarse grains in the weld structure and the hardening of the weld region, which reduce the strength and impact resistance of the welded parts. One technique to improve the mechanical properties of weld is the application of mechanical vibration to the molten pool. In this article, the effect of vibrating the part during welding on the mechanical properties of steel plates has been investigated in the tungsten inert gas (TIG) welding process. The plate is made of stainless steel 304 with 2 mm in thickness. A filler material has also been used for welding so that the effect of vibration can be observed on the weld pool region. The experimental tests have been performed under different welding conditions with respect to voltage, current, welding speed, vibrations amplitude, and frequency. Then, the resultant mechanical properties of the tested parts were measured. Also, the microstructure obtained by applying the vibration has been examined. Based on these experimental results, the effect of mechanical vibration on mechanical properties of the weld was investigated. Moreover, considering the mechanical properties obtained from these experiments, the optimum values of amplitude, frequency, and welding speed were determined.