铁道客车用SUS301L不锈钢非熔透型激光搭接焊工艺

针对不锈钢车体电阻点焊外观质量较差和密封性不良等问题,研究采用非熔透型激光搭接焊工艺进行不锈钢车体焊接,分析了激光焊接工艺参数(激光功率P、焊接速度v、离焦量F等)对搭接焊熔深和抗剪强度的影响规律.得出合理的激光搭接焊工艺参数为:P=2.0kW,v=22mm/s,F=0mm.激光焊接头剪切强度高于点焊接头,外墙板表面无焊接痕迹.     

不锈钢光纤激光熔透焊接头微观结构对疲劳性能的影响分析

利用光纤激光器对不锈钢实施熔透焊试验,分析不锈钢光纤激光熔透焊接头微观结构对疲劳性能的影响。通过微观结构分析方法分析不锈钢光纤激光熔透焊接头微观结构对疲劳性能、硬度、拉伸强度的影响规律。试验结果表明：母材的疲劳寿命比焊接接头的高;在室温腐蚀试验下,循环次数越大焊接接头最大应力荷载下降越明显,腐蚀时间越长,对疲劳性能影响越大;室温疲劳试验中,同等循环次数下,光纤激光熔透焊接头疲劳强度随厚度增大而提高;在瞬断区显微组织对疲劳裂纹扩展断口形貌没有太大影响,母材比焊接接头在疲劳裂纹扩展时更容易出现疲劳条带;焊缝数量可提高焊接接头疲劳性能,在焊缝数量一样时,增加2倍焊缝长度,能够提高疲劳极限,但提升幅度不大;焊缝硬度高于母材的;焊接试样的拉伸测试指标均低于母材的拉伸测试指标。     

板厚对不锈钢车体激光叠焊接头抗剪强度和疲劳强度的影响

为了研究板厚对不锈钢激光叠焊接头抗剪强度和疲劳强度的影响,该文针对0.8 mm +2 mm和2 mm +2 mm2种不同板厚搭配的不锈钢激光叠焊接头分别进行了拉伸试验和疲劳试验。结果表明,2 mm +2 mm接头的抗剪强度和疲劳强度均高于0.8 mm +2 mm接头。失效分析发现,2种接头的拉伸破坏由焊肉部位剪断引起的;2种接头的疲劳裂纹均萌生于2 mm未焊透板,裂纹起始位置在2个焊板之间靠近焊核附近未焊透板的热影响区,裂纹沿着焊核边缘向未焊透板外表面方向扩展,直至穿透未焊透板。对焊接接头部位的有限元受力分析可知,2种接头的应力集中程度的不同是造成它们抗剪强度和疲劳强度差异的主要原因。     

残余应力对薄板激光搭接接头力学性能的影响

针对不锈钢薄板熔透和非熔透型激光搭接焊,以80和10 mm作为考虑和不考虑残余应力影响的试样宽度,对两种宽度试样进行一系列的拉伸和疲劳试验,获得了焊接残余应力对薄板搭接接头力学性能的影响规律,进行了有关机理分析. 结果表明,搭接焊缝正、背面存有较大的纵向残余拉应力和较小的横向残余压应力;残余应力的存在会降低搭接焊接头的拉剪强度和疲劳强度. 改变激光入射角和搭接间隙,残余应力对拉剪强度的降低程度随之改变:增大入射角至20°,熔透型接头降低程度达到0°时的7倍,而非熔透型为10倍;搭接间隙在一定范围内增大时,残余应力对拉剪强度的降低程度也随之加剧.     

轨道车辆不锈钢车体激光焊部分熔透搭接接头疲劳性能研究

根据部分熔透搭接激光焊工艺特点和结合不锈钢车体侧墙结构,采用不同规格厚度及表面加工类型组合不锈钢进行部分熔透搭接激光焊,焊后对试样进行腐蚀和疲劳试验,以研究其疲劳性能。试验结果表明：疲劳裂纹均启裂于下板上表面的热影响区,并向下板内部扩展;在试样的宽度方向上,裂纹从下板一侧启裂,向另一侧扩展。疲劳断口扫描电镜分析发现,所有断口整个断裂界面比较粗糙,未观察到明显韧窝和腐蚀引起的点腐。在相同疲劳循环次数的条件下,激光焊部分熔透搭接接头疲劳强度随厚度增加而提高。腐蚀疲劳试验结果表明,在高载荷条件下,腐蚀时间对接头疲劳性能的影响较小;随着疲劳循环次数的增加,腐蚀对接头疲劳性能的影响逐渐增大。     

轨道车辆不锈钢车体典型接头激光焊接工艺特性研究

通过优化两种板厚组合(2?mm+1.5?mm和1.5?mm+2?mm)的不锈钢非熔透型激光搭接焊的焊接工艺参数,实现对多参量耦合工况条件下的激光焊接质量控制,并对其疲劳性能进行研究.运用正交试验方法设计了焊接工艺试验,根据正交试验结果分析两种板厚组合焊接接头的3种关键焊接参数(焊接功率P、焊速v、离焦量f)与抗剪强度之间的关系,得出最优焊接工艺参数,即1.5?mm+2?mm板厚组合:P=3700?W,v=4330?mm/min,f=+4?mm;2?mm+1.5?mm板厚组合:P=3700?W,v=4580?mm/min,f=0?mm,对比分析最佳焊接工艺参数下两种板厚组合激光焊焊接接头的疲劳性能,2?mm+1.5?mm板厚组合焊接接头疲劳强度高于1.5?mm+2?mm板厚组合,为不锈钢车体激光焊接参数的进一步优化及疲劳性能研究提供了参考.     

不锈钢车体非熔透激光搭接焊热源模型

用激光搭接焊取代电阻点焊是解决不锈钢车体表面质量和密封性问题的理想方法,但在不锈钢车体非熔透型激光搭接焊工艺试验过程中,发现在常用的激光焊接工艺参数范围内,搭接接头的熔池形状近似花瓶状,不同于通常情况下热导焊时呈碗状和深熔焊时呈钉形.为此,基于ABAQUS有限元分析软件,分别对高斯热源、高斯热源+柱体热源、三维正锥体热...     

高端不锈钢轨道车辆激光叠焊技术开发与应用

针对高端不锈钢地铁产品采用电阻点焊工艺出现外观水平低、效率低等问题,国内首创性开发出采用薄板搭接激光焊部分替代电阻点焊方法制造的不锈钢轨道车辆新产品.介绍了不锈钢车体激光搭接焊工艺开发,优化了工艺参数,得出在光斑直径为0.6?mm的前提下,激光功率1200?W、焊接速度30?mm/s可获得剪切强度和下板外表面质量合格的接头.通过明确焊缝质量标准(熔深0.9?mm)并进行焊缝质量监测装置开发,搭建激光焊制造体系,实现了激光焊新技术在高端不锈钢轨道车辆产品中的批量化应用,激光焊不锈钢车体质量降低1.8 t,侧墙抗横向冲击性能显著提升,提升车体寿命15％以上.     

轨道客车用不锈钢等离子填丝搭接焊接头力学性能研究

针对板厚3mm SUS301L-MT与板厚5mm SUS304不锈钢板材搭接方式,分别采用等离子填丝焊工艺和电阻点焊工艺进行焊接,分析比较等离子填丝焊和电阻点焊两种方法搭接接头的准静态剪切拉伸性能和剪切拉伸疲劳性能。试验结果表明:在确定的焊接工艺参数条件下,等离子填丝焊和电阻点焊接头均符合铁道客车用不锈钢焊接接头的设计要求,且与电阻点焊接头相比,等离子填丝焊接头的剪切拉伸载荷提高约1.3倍,在循环寿命为2×106条件下的疲劳极限提高67.1%。     

基于响应面法的不锈钢车体激光焊接工艺参数优化

为解决电阻点焊不锈钢车体表面质量差、密闭性差等问题,采用二次回归旋转设计试验方案,基于响应面法建立了不锈钢车体激光焊接工艺参数(激光功率、焊接速度、离焦量)与预测响应值(熔深、熔宽、接头剪切拉伸载荷)之间的数学模型,能够根据车体表面质量和接头强度的要求优选焊接工艺参数.并通过优化激光焊接工艺参数来预测激光搭接焊接头的熔深、熔宽以及接头的剪切拉伸载荷,实现焊缝成形与接头强度的最佳组合,为改善不锈钢车体焊接表面质量提供了新的工艺途径.     

PMMA与304不锈钢激光焊接

研究聚甲基丙烯酸甲酯(PMMA)塑料与304不锈钢激光焊接热传导技术,采用正交试验法分析聚甲基丙烯酸甲酯和304不锈钢之间的焊接质量. 对焊接后的试样进行拉伸测试和切片试验,用能量密度定量判定焊接结果,分析多种焊接因素对抗拉强度和焊缝宽度的影响. 利用正交试验极差分析法对试验数据进行处理,获得透明聚甲基丙烯酸甲酯和304不锈钢之间激光热传导焊接的最佳焊接工艺参数. 结果表明,焊接因素对焊接强度的影响从大到小的顺序为焊接速度、脉冲宽度、保护气体流量、峰值功率、光斑直径和脉冲频率.     

不锈钢SUS 301L激光填丝搭接焊工艺

以接头形式0.6+2mm的不锈钢SUS 301L为对象,研究激光填丝焊激光功率、焊接速度、送丝速度3个主要工艺参数对焊缝成形、接头截面形貌及连接强度的影响规律。结果表明,随着激光功率的增加,焊缝熔深和熔宽增大,余高减小;随着焊接速度的增加,焊缝熔深、熔宽、余高均减小;随着送丝速度的增加,焊缝熔深和熔宽减小,余高增大。接头的最大拉力为14.43 k N,断裂在上层薄板母材中,焊缝强度大于母材。     

Development of laser welding technology for fully austenitic stainless steel

The radial stainless steel plates (RPs) used for Toroidal field (TF) coils in the International Thermonuclear Experimental Reactor (ITER) are 13 m long, 9 m wide and 10 cm thick, which are quite large. Even though they are very large structures, high manufacturing tolerances and high mechanical strength at 4 K are required. It is also required that each RP should be fabricated every three weeks. Therefore, the authors intend to develop efficient manufacturing methods for an ITER TF coil RP. Laser welding is then selected as a welding method for RP. Especially, the development of high technology laser welding is necessary to prevent hot cracking in the material used for the RP; namely, fully austenitic stainless steel with high nitrogen content. The authors carried out trial laser welding experiments aiming at its application to RP. As a result, it was effective to make the angle of back inclination of the weld head at a uniform welding speed. It also seemed that the sensitivity of hot cracking could be reduced by optimizing the chemical compositions of material used for RP. The base material and the welded joints satisfied mechanical properties in 4 K. The application of the laser welding technology to the fully austenitic stainless steel was therefore demonstrated.     

不锈钢薄板T形接头激光穿透焊工艺

采用YLS-6000型激光焊接系统对304不锈钢进行穿透焊,研究激光功率和离焦量对T形接头焊缝成形、显微组织和显微硬度的影响。结果表明,随着激光功率的增加,焊缝的熔深、熔宽和搭接处焊缝宽度都增大;焊缝搭接处焊缝宽度在离焦量为-2 mm时达到最大,同时考虑深宽比,离焦量为0 mm时焊缝成形较好;焊缝区组织为以奥氏体柱状晶为基体,间隙中分布着网状δ铁素体;焊缝区硬度略低于母材,且随着激光功率的增加,焊缝区组织粗化,硬度降低。创新点：对不锈钢T形接头进行了激光穿透焊接,较为系统的分析了激光功率、离焦量等对焊缝成形的影响。综合考虑搭接处焊缝宽度和熔深,离焦量为0 mm时,焊缝成形最好。     

Tailored blank welding between low carbon steel sheet and STS 304 stainless steel sheet by CO2 laser beam

A basic reseach of tailored blank welding between a low carbon steel sheet and a STS 304 stainless steel sheet was carried out with CO₂ laser beam. The materials used in this work were a low carbon steel sheet with a thickness of 0.9 mm and a STS 304 stainless steel sheet with the same thickness. Experiments were carried out by applying the Taguchi method to obtain optimized conditions in order to apply this tailored blank laser welding method in the practical manufacturing process. In order to compare the laser welding results with the conventional welding process, GTA welding was carried out for the same materials. Optical microscopy, SEM and XRD analyses were performed to observe the microstructures and to analyze the various phases. A tensile test, hardness test and Erichsen test were performed to evaluate the formability of welded specimens. In addition, immersion test was carried to estimate corrosion resistance. A WDS analysis showed that laser welding resulted in almost the same dilution of both low carbon steel and stainless steel in welded metal, meanwhile, GTA welding resulted in more dilution of stainless steel due to its slower heat conductivity. The formability of the laser welded specimen reached 83% of that in base metal. On the other hand, it was 63% in the case of GTA welding. During the tension test, base metal was fractured in the case of a laser welded specimen, meanwhile the welded zone was fractured in the case of the GTA welded specimen. The corrosion test showed that weight loss per unit area was less in the laser welded specimen than that of the GTA welded specimen.     

低功率YAG激光-MAG电弧复合焊接不锈钢

以0Cr18Ni9Ti不锈钢钢板为试验材料,研究了低功率脉冲YAG激光-脉冲MAG电弧复合热源和单脉冲MAG焊接不锈钢.结果表明,低功率脉冲YAG激光-脉冲MAG电弧复合热源同样具有大功率激光-电弧复合焊接才有的增加熔深、提高焊接速度、稳定焊接过程等优点;低功率脉冲YAG激光的加入改变了电弧形态,电弧根部被吸引和压缩现象显著,提高了能量利用率;与单脉冲MAG堆焊相比,在相同焊接速度下复合焊最大能增加熔深1.3倍,在相同熔深下复合焊的焊接速度可以提高50%;复合焊焊缝的晶粒较单MAG焊缝中的晶粒细小,其焊缝抗拉强度比单MAG的好,断裂属于延性断裂.     

不锈钢的激光焊接

比较了高功率CO2激光和YAG激光焊接不锈钢时的特点，分析了工艺参数对焊缝形状和接头显微组织的影响。