微型剪切试验在焊丝选择中的应用

为了保证特大型水电站引水钢管焊接接头的质量,在焊丝的筛选过程中,采用了一种新的测定非均质材料力学性能的方法——微型剪切试验,该方法能够准确地测定焊接接头各狭窄区域内材料的性能值以及它们的变化规律,特别是熔合线附近材料性能的变化梯度。通过微型剪切试验,选出了与钢管焊接接头较佳匹配的焊丝。     

青草背长江大桥焊接工艺评定试验

介绍了青草背长江大桥焊接工艺评定试验。对全桥的接头形式及板厚进行归纳,选取典型焊缝进行焊接工艺评定试验。选择了匹配的焊接材料并制定了严格的焊接工艺,焊后进行外观检验及超声波探伤,达到技术要求规定。通过力学性能试验,表明接头力学性能达到标准要求,低温冲击韧性有较高储备。本文可供类似工程参考。     

评定铝合金焊接接头力学性能的新途径

采用常规试验方法来测定铝合金型材构件焊接接头各区的力学性能及其变化规律是很困难的。而接头性能直接影响着结构焊接工艺的选择和强度计算。通过测定铝合金微型剪切试验和拉伸试验的性能参数，研究得出了这些性能参数之间的数学关系式。可利用这些关系式评定铝合金焊接接头的力学性能。微型剪切试验为铝合金焊接接头力学性能的评定提供了一个新途径。     

波纹管焊接接头的结构设计及试验研究

为提高大直径压力钢管波纹管膨胀节中波纹管和端管之间连接环焊缝的力学性能及改善该焊接接头的加工工艺性,提出一种新型的加不锈钢过渡环的焊接接头型式.通过对该新型焊接接头的试验研究和实际应用分析,表明该型式接头不但加工简单,可焊性好,且具有优异的抗拉和抗弯曲疲劳性能.     

关于焊接接头拉力试验断裂位置的讨论

压力容器制造过程中,不论是焊接性能试验、工艺评定还是产品焊接试板都需要进行接头拉力试验。笔者看到诸多制造厂在拉力试验报告中存在一个较为普遍、值得讨论的问题——焊接接头断裂位置。“压力容器安全监察规程”中规定焊接接头的拉力试验采用短试样,见图1A。而在此之前均采用长试样,见图1B。短试样特点是:除拉力机夹持部分外,整个试样长度为焊接接头长度。这是因为短试样受拉伸的长度是由焊缝宽度加上两侧各6mm,而这6mm长度约等于通     

厢西堡互通式立交桥钢梁焊接工艺研究

针对厢西堡互通式立交桥钢梁所用的Q345D钢，对各种焊接接头及焊接方法进行了焊接工艺评定试验，确定其焊接工艺。各项试验结果表明，试验所选择的焊接材料匹配合适，焊接参数合理，各项力学性能指标满足设计及相关规范要求。     

不锈钢焊接接头疲劳强度试验研究

通过焊接接头疲劳试验对SAF2 2 0 5双相不锈钢和 1Cr18Ni9Ti奥氏体不锈钢焊接接头S—N曲线进行详细分析 ,并与 16Mn钢焊接接头的试验结果进行比较 ,讨论不同材料焊接接头及试样接头型式对S—N曲线的影响。试验结果表明 ,SAF2 2 0 5钢和 1Cr18Ni9Ti钢焊接试样的常数m和N =2× 10 6疲劳强度与国际焊接学会 (IIW )推荐的数值有较大差异 ,采用IIW的S—N曲线对本文不锈钢焊接试样疲劳评定时 ,将给出偏于安全的结果 ;接头型式不同导致焊接接头局部应力集中有较大差异 ,因而对采用名义应力表示的S—N曲线有明显影响 ;在同类接头形式下 ,SAF2 2 0 5钢和1Cr18Ni9Ti钢焊接接头的焊态疲劳强度高于 16Mn钢焊接接头 ,而双相不锈钢接头具有更高的疲劳强度     

国产锆材的焊接工艺性能研究

本文根据锆材焊接性能特点,制定了国产压力容器用锆材料R60702焊接工艺性能试验方案,通过力学性能试验、金相组织和焊接试验过程、试验结果分析,认为国产锆材采用常规焊接方法所完成的焊接接头性能,完全能满足压力容器使用性能要求。     

基于DIC方法的铝合金焊接接头拉伸性能研究

为准确表征铝合金焊接接头拉伸性能,针对2219铝合金搅拌摩擦焊焊接接头,采用数字图像相关(DIC)方法,测量焊接接头在拉伸载荷作用下的全场应变历程,得到铝合金焊接接头焊接区在拉伸时的连续屈服强度曲线。进而结合材料弹塑性本构模型,拟合焊接区内各点处材料本构关系,并分别构造了铝合金焊接接头焊缝区及热影响区力学性能连续变化的拟合函数,使之可以表达铝合金焊接接头焊接区内任意一点力学性能。最后利用所构造的力学性能函数模拟了铝合金焊接接头的拉伸过程,数值结果与试验相吻合,表明基于数字图像相关法的应变测量可以准确地表征其焊接区内的材料力学性能。     

T91钢与P12钢管的焊接

针对合金耐热钢P12与T91异种钢材料的焊接，着重介绍工艺试验过程中的焊接材料选择及热处理规范确定。并通过制造现场的过程控制，有效地保证了异种钢接头的焊接质量。     

316L不锈钢管手工钨极氩弧焊焊接工艺

通过对316L不锈钢焊接性能的分析、手工钨极氩弧焊焊接过程的控制、焊后进行无损检测、晶间腐蚀、力学性能等项目的数据分析,焊接接头的机械性能和耐腐蚀性达到了工艺要求,保证了316L不锈钢管的焊接质量,为广大焊接工作者提供参考。     

不锈钢复合板焊接接头晶间腐蚀失效分析

针对不锈钢复合板焊接接头出现晶间腐蚀裂纹问题,采用光学显微镜、扫描电镜、XRD等技术手段对复合板焊接接头的组织、成分以及相组成进行检测和分析,对焊接工艺规范和热处理制度对焊接接头耐蚀性的影响进行探讨。结果表明,接头焊缝区铁素体含量18．3％,晶粒度9．5级,过渡层焊缝铬的含量9．58％,低于耐蚀性要求;接头产生了σ等硬脆相,这些因素都增大晶间腐蚀敏感性;焊接线能量过大,将降低接头的腐蚀性能;复合板整体消应热处理可以取消。     

船舶的焊接缺陷分析及质量控制

船舶焊接技术是船舶建造中的关键技术之一,焊接技术高低直接影响着船舶建造质量。如果焊接存在缺陷,会使产品抗腐蚀性能下降或者不能满足力学性能的要求,造成渗漏或者结构断裂,无法保证船舶安全航行和作业。本文从焊接缺陷进行分析,通过实践分析提出相应预防措施,提升焊接技术,控制焊接质量,进而提升船舶质量。     

高强度钢板Domex700MC的焊接工艺性能研究

在分析Domex700MC高强钢组织、性能的基础上,进行了手工电弧焊、气体保护焊工艺及其焊接接头显微组织与力学性能的研究,研究结果表明：选择合适的焊接材料,可以获得满意的接头性能;焊接接头最薄弱处是热影响区;为提高焊接接头的综合力学性能,控制焊接热输入是必要的。     

焊接工艺参数对5383铝合金搅拌摩擦焊接头耐腐蚀性的影响

在制备不同焊接工艺条件下的5383铝合金搅拌摩擦焊接头的基础上,利用扫描电镜与能谱分析方法研究搅拌摩擦焊接头典型区域的宏观形貌特征与显微形貌特征,得到焊接速度、搅拌头转速及搅拌头压力等焊接工艺参数对接头耐腐蚀性的影响规律,结果表明:在特定的焊接工艺条件下,焊缝区域会产生S线。S线是接头腐蚀最严重的区域,其原因是由Mg元素偏聚、大量微孔的聚集与锰铁化合物的形成等三方面因素造成的;除S线及其附近区域外的焊缝其他区域的耐腐蚀性优于母材。同时,分析三种因素导致焊接接头耐腐蚀性降低的原理,阐述不同焊接工艺参数对5383铝合金搅拌摩擦时接头中S线形成的影响,提出利用减少焊接速度、增加搅拌头转速与提高搅拌头压力的方法来改善5383铝合金搅拌摩擦焊接头的耐腐蚀性。     

奥氏体不锈钢热轧板材的焊接性试验研究

通过焊接接头无损检测、力学性能、耐晶间腐蚀性能试验及显微硬度测定,研究了经手工钨极氩弧焊（TIG）SUS304热轧板材的焊接性能。结果表明,采用TIG焊接方法和较小的焊接规范,所得焊接接头各项性能良好;热影响区晶粒长大不严重,焊缝与母材熔合良好。利用双环动电位再活化法（DL-EPR）测定SUS304奥氏体不锈钢焊接接头的晶间腐蚀敏感性,发现其无晶间腐蚀倾向。     

Optimization of pulsed current in resistance spot welding of Zn-coated hot-stamped boron steels

Metallic coatings have been widely used for hot-stamped boron steel in automotive applications. Surface coating in hot-stamped boron steels has improved corrosion resistance. However, a thick coating layer degrades resistance spot weldability. In the case of a Zn-coated hot-stamped boron steel, the high contact resistance and material stiffness with low vaporization temperature of the alloyed layers result in a narrow current passage at the faying surface. Expulsion occurs at low current due to rapid heat development, resulting in a narrow weld current range. The pulsed current can control the heat input by applying a fast cool time during welding to improve the mechanical properties of the joint and acceptable current range. In this study, Zn-coated hot-stamped steels were resistance spot welded using various pulse current procedures, and welding condition was optimized via three pulsed current steps. Step 1: Contact area was controlled without nugget formation. Step 2: Nugget growth was minimized and contact area was maximized. Step 3: The maximum acceptable current range and nugget diameter were achieved. These welding conditions improved the acceptable current range and mechanical properties of spot welds due to increased spot weld size.

     

电子束焊接在特殊精密齿轮加工中的应用

电子柬焊接是一种新型焊接技术，它与其它工艺相比具有焊缝质量高、变形小及效率高等特点，在机械加工中有广阔的应用前景。本文以特殊齿轮为例介绍了电子柬焊接工艺的实际应用。     

An investigation on SA 213-Tube to SA 387-Tube plate using friction welding process

Friction welding of tube to tube plate using an external tool (FWTPET) is a relatively newer solid state welding process used for joining tube to tube plate of either similar or dissimilar materials with enhanced mechanical and metallurgical properties. In the present study, FWTPET has been used to weld SA 213 (Grade T12) tube with SA 387 (Grade 22) tube plate. The welded samples are found to have satisfactory joint strength and the Energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) study showed that inter metallic compound is absent in the weld zone. The different weld joints have been identified and the phase composition is found using EDX and XRD. Microstructures have been analyzed using optical and Scanning electron microscopy (SEM). The mechanical properties such as hardness, compressive shear strength and peel test for different weld conditions are studied and the hardness survey revealed that there is increase in hardness at the weld interface due to grain refinement. The corrosion behavior for different weld conditions have been analyzed and the weld zone is found to have better corrosion resistance due to the influence of the grain refinement after FWTPET welding process. Hence, the present investigation is carried out to study the behavior of friction welded dissimilar joints of SA 213 tube and SA 387 tube plate joints and the results are presented. The present study confirms that a high quality tube to tube plate joint can be achieved using FWTPET process at 1120 rpm.     

Study of laser butt welding of SUS301L stainless steel and welding joint analysis

This paper describes a study on laser butt welding of 4 and 2 mm SUS301L stainless steel and a detailed analysis of welding joints. The gap tolerance of butt joint was also studied with optimized process parameters. The electrolytic etching in 10 % oxalate solution was used to test the intergranular corrosion of the 4 mm SUS301L welded joint. Fatigue property of the 2 mm SUS301L welded joint was tested under the conditional cycle times of 1?×?10⁷. Using optical microscopy, the changes of metallurgical microstructure in the weld zone of 4 mm SUS301L were also studied. It has been found that laser butt welding of 4 mm SUS301L is able to achieve sound metallurgical morphology and high strength weld joint when the butt gap is within certain tolerance. The weld joint also has good resistance to intergranular corrosion and has a fatigue limit of 310 MPa.