不等厚高强钢激光拼焊板焊缝组织及胀形性能分析

采用激光焊接方法,针对1.8mm厚的SAPH440与2.2mm厚的DP600高强钢实施激光拼焊.测试了不等厚拼焊板焊接接头的金相组织以及显微硬度,然后通过杯突试验对所得到的不等厚高强钢拼焊板的胀形性进行了研究,进一步与母材的胀形性相比较.结果表明,焊缝的金相组织为针状铁素体和板条马氏体,焊缝两侧硬度分布不同,焊缝处的硬度要高于母材.拼焊板的杯突值低于任何一侧母材的杯突值,焊缝的位置对不等厚拼焊板的胀形性有一定的影响,薄板所占比例越大拼焊板的胀形性越好,在胀形成形过程中焊缝向厚板侧移动.     

不等厚激光拼焊板杯突试验及模拟

针对厚1.8 mm的SAPH440和厚2.2 mm的DP600不等厚异质板材采用激光焊接技术实现拼焊,进一步研究SAPH440和DP600的不等厚激光拼焊板的焊接接头性能和成形性能。针对拼焊板的胀形性进行杯突试验,研究表明,当薄板SAPH440所占的比例较厚板DP600大时,拼焊板的杯突值低于任何一侧母材的杯突值,即拼焊板的胀形性低于母材。并利用Dynaform软件对拼焊板的成形过程进行仿真分析：结果表明两侧板材变形不均匀,焊缝向厚板侧移动。     

22MnB5/H340LA异种汽车用钢激光拼焊接头组织性能研究

对1.5 mm厚的热成形钢(22MnB5)和低合金高强钢(H340LA)进行了激光拼焊。测试了接头的杯突性能、拉伸性能和硬度。采用光学显微镜观察拼焊板接头各区域的微观组织。结果表明,采用设定的拼焊工艺获得的焊接接头杯突值(IE)较22MnB5母材下降率小于30%,破裂方向垂直于焊缝;拉伸试样断裂在H340LA母材上。22MnB5侧热影响区硬度最高,焊缝区次之。22MnB5侧的热影响区宽约0.35 mm,H340LA侧的热影响区宽约0.27 mm,焊缝宽度为1.02 mm。22MnB5侧热影响区完全淬火区由马氏体组成,不完全淬火区由马氏体+铁素体组成,焊缝组织主要为马氏体,H340LA侧的热影响区主要为铁素体和贝氏体。     

DP590激光拼焊板焊接性能和成形性

激光拼焊板作为车身轻量化的重要技术,在汽车行业中应用前景广阔。研究了1.6 mm和2.0 mm规格的DP590激光拼焊板的焊接接头力学性能,并对其成形性能进行了分析。结果表明,焊接接头强度高于母材强度,但其延展性低于母材;焊缝区的显微硬度分布均匀,热影响区不存在明显的软化点;杯突试验中焊接接头开裂位置均在母材上,断口为韧性断裂,焊缝质量良好。     

差厚高强钢激光拼焊板拉伸失稳行为研究

对0.7mm/1.0mm厚度组合的B170P1钢激光拼焊板试件进行半球凸模胀形试验,分析不同应变状态下拼焊板的变形、失稳特点及应变分布情况,研究其拉伸失稳规律。研究表明,拼焊板试件的变形失稳主要发生于薄侧母材,且随应变状态由单拉向平面等双拉的转变,应变分布趋于均匀,失稳位置向焊缝靠近;在变形过程中,靠近焊缝的薄侧母材在平行于焊缝方向的变形受到厚侧母材及焊接区的影响,其应变路径快速向平面应变漂移,达到成形极限状态,降低了拼焊板的成形性能。焊缝的存在导致差厚激光拼焊板各部分变形不均匀,在差厚激光拼焊板的实际应用中,应采取适当措施抑制薄侧母材的局部变形,增加厚侧母材塑性变形的比例,提高差厚拼焊板的冲压成形性。     

HSA 340高强度钢激光拼焊板焊缝组织与拉伸性能分析

选取1.5mm和2.0mm厚度的HSA340高强度钢进行激光拼焊,焊后对焊接接头进行金相检验及微观硬度测试,分析了焊缝、母材及热影响区的组织特性;对焊后试样进行拉伸试验,分析了高强度钢激光拼焊板的单拉特性,并结合拼焊板的微观组织,详细阐述了拉伸性能和焊接组织的关系。结果表明,拼焊板焊接热影响区的微观特性,决定了该区域具有良好的力学性能;提高焊缝中的针状铁素体含量,可提高试件拉伸性能;焊缝中马氏体的存在,提高了焊缝抗拉强度与硬度。     

SPCC冷轧钢光纤激光拼焊工艺及焊缝组织研究

采用数控光纤激光焊接机,对1.2mm+2.5 mmSPCC冷轧板进行不等厚拼焊,研究了焦点位置、激光功率与焊接速度、保护气体等工艺参数对焊缝形成、熔深的影响,优化工艺参数可以获得深而窄、均匀美观的焊缝;焊后对焊接接头进行金相分析和拉伸、杯突试验.结果表明,热影响区组织细小、性能优良,焊缝冷却后出现错位马氏体和针状铁素体组织,提高了焊缝的硬度和韧性,拉伸断裂位置位于母材,表明焊接接头的力学性能优于母材.     

高强度钢差厚板激光拼焊焊缝成形及组织分析

选取2.0 mm,1.5 mm厚的HSA340板材和0.7 mm厚的H340LAD Z板材,按强度相近厚度不同原则两两搭配进行激光拼焊.焊后选取具有代表性的焊缝横截面进行金相组织检验,并对焊缝接头各区域进行硬度测量,分析了激光焊缝接头各区域金相组织及其硬度的变化.结果表明,差厚板激光拼焊过程中,母材散热情况不同,会造成焊缝金相组织在各自靠近母材的局部区域有很大差异;激光拼焊板的热影响区宽度窄,与母材及焊缝间有明显的界线,生成的组织细密;焊缝及热影响区的硬度值均大于母材;合理调整激光光束的入射位置和入射角度,可以显著改善焊缝成形,提高拼焊板的接头质量.     

ST14钢与DP600冷轧双相钢激光拼焊工艺研究

采用500 W固体脉冲激光焊接系统对厚度均为1.5 mm的ST14钢和DP600冷轧双相钢进行了激光拼焊试验,研究不同激光焊接工艺下的焊接接头形貌,并对工艺优化后的焊接接头显微组织、静态拉伸进行测试。试验结果表明:当激光焊平均功率为370 W、焊接速度为300 mm/min、焊接电压为260 V时,激光拼焊板焊接接头表面形貌和横截面形貌满足激光焊焊缝质量评价标准要求,该焊接接头拉伸断口位于ST14一侧母材区,屈服强度和抗拉强度与ST14钢母材相当。随着脉冲频率的增加,焊缝的宽度、熔深和热影响区宽度增加。     

不等厚DC56D+Z/HC180BD+Z钢激光拼焊焊接接头性能分析

对1.5 mm厚的DC56D+Z与0.7 mm厚的HC180BD+Z两种常用汽车板材进行激光拼焊,测试了不等厚激光拼焊板的金相组织、显微硬度和力学性能。结果表明:焊缝处与基体的金相组织均为铁素体,在焊接热循环的作用下,焊缝与基体的组织形貌差异较大。焊缝两侧硬度呈非对称分布,焊缝处最高硬度达到200 HV,高于母材。接头的单向拉伸断裂发生在HC180BD+Z钢侧,强度略低于HC180BD+Z钢母材,但断后伸长率仅为HC180BD+Z钢母材的56.8%。杯突试验后,断裂位置均发生在薄板侧,随着薄板侧占比增大,其焊缝由直线型转变为抛物线型。     

Nd:YAG激光焊接800 MPa TRIP钢的接头组织与性能

采用Nd:YAG激光对强度为800MPa,厚度为1.2mm的TRIP钢板进行焊接.研究焊接速度对焊缝外观和截面成形的影响及接头的组织特点、硬度、强度和成形能力.激光功率相同,焊接速度较低时焊缝易产生气孔,速度较高时易发生飞溅;焊接速度对焊缝熔深及熔宽也有影响.焊缝组织主要由马氏体构成,从焊缝、热影响区到母材,组织中马氏体含量下降,接头的最高硬度出现在焊缝或热影响区.在平行于焊缝方向,焊接接头的抗拉强度高于母材,垂直于焊缝方向,接头的抗拉强度与母材相当.由于焊缝中出现马氏体,接头的塑性和韧性降低,板材的冲压成形能力下降.     

CO_2激光焊接600MPa DP钢接头组织与性能

采用CO2激光对抗拉强度为600MPa,厚度1.4mm的DP钢进行焊接.研究焊接速度对焊缝外观和截面成形的影响、接头的组织特点、硬度、强度和成形能力.结果表明,激光功率相同,焊接速度较低时焊缝易产生气孔,焊接速度较高时易发生飞溅;焊接速度对焊缝熔深及熔宽也有影响.焊缝区组织主要由马氏体构成,从焊缝、焊接热影响区到母材,组织中马氏体含量下降,接头的最高硬度出现在焊缝或热影响区.在平行于焊缝方向,焊接接头的抗拉强度高于母材,垂直于焊缝方向,接头的抗拉强度与母材相当.由于焊缝出现马氏体组织,接头的塑性和韧性降低,板材的冲压成形能力下降.     

On formability of tailor laser welded blanks of DP/TRIP steel sheets

Abstract

This paper aims to evaluate the formability of tailor welded blanks of dual phase (DP600)/transformation induced plasticity (TRIP700) steel sheets. In this work, bead on plate butt joints of 2·5 mm DP600 and 1·2 mm TRIP700 steel sheets were performed using CO₂ laser beam welding. Microhardness measurements and transverse tensile testing were carried out to characterise the welds. The formability of base metals and welds were investigated by standard Erichsen test. In a perpendicular tensile test to the weld line, all specimens were fractured at the TRIP base metal, and the strengths were somewhat higher than those of base metal. There was a significant reduction in formability caused by welding of the DP600/TRIP700 steel sheets, and the formability increased with increasing welding speed.     

镀锌薄板TIG拼焊的焊缝组织及成形性能

采用钨极惰性气体焊对镀锌薄板 SGCC 实施等厚拼焊,测试分析了拼焊板焊接接头的金相组织、显微硬度,并对拼焊板和母材试样进行杯突试验.结果表明,在拼焊过程中,母材的散热情况不同会造成焊缝金相组织在靠近母材的局部区域有很大差异.焊缝熔合区组织为粗的片状与块状先共析铁素体沿柱状晶界分布,晶内为魏氏体组织和片状珠光体,热影响区为块状的珠光体和铁素体,导致了焊缝及其热影响区的硬度均高于母材,对拼焊板的整体成形性能产生负面影响;同时,焊缝杯突值较母材有一定程度的降低,揭示其焊缝深冲性能低于母材.

Abstract：

The microstructure and micro-hardness of welded joint of SGCC by tungsten inert-gas (TIG) welding are studied, and the cupping test of Tailor-welded blank and base metal are studied.The results show that in the welding process, the microstructure of weld will have great diversity at local region closing parent metal because of the different cooling condition of the parent metal. The microstructure of welding fusion zone is massive sheet proeutectoid ferrite distribution along the columnar grain boundaries, intragranular organizations are Widmanstatten and sheet pearlite structure, and the microstructure in HAZ is massive pearlite and ferrite, which make the micro-hardness value of welding seam and HAZ higher than that of base metal and lead negative influence to the formability of Tailorwelded blank. The cupping value of weld seam reduces to some extent compared with that of base metal, which indicates that the formability of weld seam is not good as that of base metal.     

Investigations Into the Influence of Weld Zone on Formability of Fiber Laser-Welded Advanced High Strength Steel

In this study, two different dual phase steel grades DP980 and DP600, and IFHS steel sheets were laser welded by a 2-kW fiber laser. The weld quality of these three different LWBs was assessed with the help of microstructure, micro-hardness and transverse tensile tests. Tensile testing of longitudinal and miniature samples was performed to evaluate the mechanical properties of the weld zone. Formability of parent materials and LWBs were assessed in bi-axial stretch forming condition by Erichsen cupping test. To validate the weld zone properties, 3-D finite element models of Erichsen cupping test of LWBs was developed, and the failures in the deformed cups were predicted using two theoretical forming limit diagrams. It was observed that hardness of the fusion zone and HAZ in laser welded DP600 and IFHS steels was more compared to the respective parent metal. However, 29% reduction in hardness was observed at the outer HAZ of DP980 steel weldments due to tempering of martensite. Reduction of formability was observed for all the LWBs with two distinct failure patterns, and the maximum reduction in formability was observed in the case of DP980 LWBs. The presence of the soft zone is detrimental in forming of welded DP steels.     

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拼焊板Tailor welded blanks（TWB）作为一种先进的制造工艺技术,在满足零件不同性能要求的同时,还能满足减少重量,节约能源要求。文章就不等厚异质高强钢拼焊板的拉伸性能进行了研究,结果表明：当焊缝平行于拉伸方向时,断后伸长率较大,与焊缝垂直于拉伸方向相比较,板材有较大的拉伸变形能力,较好的成形性能;焊缝平行于拉伸方向时,断口为韧性断裂与解理断裂的混合型形貌,焊缝垂直于拉伸方向时,断口形貌为等轴韧窝。     

激光拼焊板焊接工艺参数的优化

为了得到最优的焊接工艺参数,提高拼焊板的成形性能,采用脉冲激光器对DC04薄板进行焊接,通过进行多组试验,对比研究了各个焊接工艺参数对焊接过程、焊缝的宏观现象及微观组织的影响,从而得到各个焊接工艺参数的可选区间.设计了1组三因素三水平的正交试验,得到了最优化的1组焊接工艺参数.试验表明,采用工艺参数为:焊接电压270V...