焊后热处理对异种钢焊缝组织和性能的影响

选择高强钢和超低碳钢异种钢焊缝试样,进行不同温度的热处理,对比不同保温温度下焊缝区域的金相组织、力学、杯突和洛氏硬度等性能,研究保温温度对异种钢焊缝的影响。结果表明,900℃保温5min后,焊缝熔合度良好,焊缝强度较高,焊缝熔合区附近的组织较为细小;随保温温度升高,试样硬度呈下降的趋势,且热影响区的硬度比母材明显提高。     

酸轧Miebach激光焊接工艺参数的研究

激光焊接技术凭借着高效、稳定和自动化水平高的优势，普遍应用于现代化钢铁行业酸轧生产线的带钢连接工艺。通过对激光焊机的焊接接头进行测量显微硬度和观察显微组织、拉伸试验、杯突试验等试验方法，来测试焊缝的质量，论述了目前的焊接工艺参数的合理性。     

高强度桥梁钢Q500qE角焊缝焊接工艺研究

采用CO_2气体保护焊和埋弧自动焊进行高性能桥梁钢Q500qE熔透及T型角焊缝的焊接工艺试验,结果表明,焊接接头成形良好、机械性能达到要求,焊缝组织以针状铁素体为主,热影响区组织以贝氏体为主,保证了接头良好的强韧性。利用本试验焊接工艺焊接的角焊缝各项检验均合格,本试验焊接工艺及钢板、焊材可用于大跨度桥梁角焊缝的焊接施工。     

焊缝金相分析系统的设计与实现

针对实际焊接工艺研究的需要,在对图像处理技术进行探索的基础上,对焊缝金相组织图像处理技术进行了研究,并在Visual C＋＋平台上开发了金相组织图像分析程序。在人机交互下,通过对金相图像进行图像预处理、图像复原、图像分割和图像识别等处理,使数码拍摄的焊缝金相组织图像可以由图像处理技术进行分割并识别,同时程序还完成了焊缝金相组织的微观结构特性参数的统计。这些参数的获得为实际焊接工艺研究提供了重要的试验参数。     

不锈钢—钢复合薄板的焊接

讨论了不锈钢－钢复合薄板的微束等离子弧焊接的工艺,提供了和这种工艺焊接的焊缝形状,化学组成,金相组织,耐蚀性和力学性能的资料,指出这种焊接技术在该种新型结构材料应用中的意义。     

稀土对Q420qNH焊缝低温韧性及耐腐蚀性能研究

文章对比分析了稀土元素对耐候桥梁钢Q420qNH焊接接头力学性能、金相组织、耐腐蚀性能的影响.使用专用耐候焊丝对耐候桥梁钢Q420qNH和Q420qNHRE进行相同的焊接工艺下的接头性能对比试验,结合接头常规力学性能、金相组织、盐雾腐蚀试验的结果,表明稀土元素可有效的提高耐候桥梁钢Q420qNH焊接接头的韧性、低温冲击性能和耐腐蚀性能.     

铝合金枕梁厚板长直焊缝自动焊接研究

通过对地铁枕梁部件长直焊缝手工焊与自动焊的对比试验,研究了自动化焊接技术在枕梁焊接中的应用.从渗透检测、X射线及微观金相检测、力学性能测试等方面进行了分析,确定了枕梁自动化焊接工艺速度快,效果好,符合设计要求;所得焊缝外观好,金相组织细小、均匀.     

20MnSi钢闪光对焊无头轧制焊缝的变形及金相组织

研究了棒线材无头轧制的工艺参数，选择20MnSi钢作为研究对象，采用预热闪光焊接模拟高温状态下的坯料焊接。焊后轧制使用φ300轧机。通过轧制研究了轧制前后轧件焊缝的变形情况，焊缝轧制前后的硬度情况和焊缝金相组织的变化。结果表明，合理的焊接工艺和足够的焊后轧制变形能够使焊缝的组织性能与基体相近，满足使用要求。     

B级钢摇枕、侧架焊修工艺的探讨

本文详细介绍了B级钢摇枕、侧架焊修工艺性能和影响焊接质量的各种因素,通过实验剖析了不同焊接规范下焊缝及其影响区的金相组织对裂纹形成的影响,提出了合理的焊接规范和工艺要求。     

冷轧制桶用钢扩径开裂研究

针对A钢厂CSP+BAF流程生产的冷轧制桶用钢客户加工使用过程中焊缝扩径开裂问题,通过金相显微镜、SEM对比分析了焊缝处热影响区及母材微观形貌及金相组织。结果表明,热影响区组织相比母材组织晶粒细小、无明显方向性、位错密集、韧窝较浅,热影响区呈现脆性断裂形貌,母材呈现塑性断裂形貌。通过调整焊接参数,降低焊接电流速度、提高焊接时间、降低焊后冷却速度,焊缝处扩径开裂得到一定程度的控制,但不能完全消除。进一步对比行业中其他钢企制桶用钢成分控制,对比分析碳当量及冷裂纹敏感指数,进一步优化该钢厂冷轧制桶用钢成分,降低Mn含量,提高Si、Cr含量,在保证产品强度的同时降低碳当量及冷裂纹敏感指数,最终焊缝扩径开裂问题得到有效解决。     

热输入对S43932超纯铁素体不锈钢焊接接头组织性能的影响

对1.0 mm厚度的S43932不锈钢冷轧板分别进行88、101、132、188 J/mm的钨极氩弧焊焊接,研究了焊接区的显微形貌和相组成。详细分析了垂直焊缝、平行焊缝和带缺口焊缝试样的拉伸性能及焊缝杯突试验结果,当热输入为101 J/mm时,焊接接头具有最佳的拉伸及成形性能匹配,之后随热输入＞101 J/mm,焊接接头抗拉强度和埃里克森杯突值急剧下降。焊接接头良好的力学性能与焊接区小尺寸晶粒的形成及大量富Ti(Nb,Ti)(C,N)相的析出有关。     

Microstructure and properties of laser-arc hybrid welding of high-strength low-alloy steel

Laser-arc hybrid welding has the characteristics of optimal surface formation and greater penetration;it is extensively used in the welding of plates of medium thickness.However,for hybrid welding of lasers,the welding seam cooling rate is rapid;thus,the welding seam has a higher tendency to significantly harden,which has a negative impact on the weld quality of the high-strength low-alloy(HSLA)steel plates of medium thickness.In this study,laser-arc hybrid welding is performed on the BG890QL HSLA steel produced by Baoshan Iron&Steel Co.,Ltd.,and the quenching tendency of the welded structure is examined.The results demonstrate that the specific growth direction of the columnar crystal structure of the laser-arc hybrid welded joint is obvious.However,at the center and top of the welded seam,there are equiaxed crystals.The impact properties at room temperature and-40℃of the weld area are 58.0 J and 40.0 J,respectively,and those of the heat-affected zone(HAZ)are 147.0 J and 66.5 J,respectively.The impact performance can meet these requirements.Laser-arc hybrid welding of HSLA steel can yield strong and durable welds and the HAZ structure to meet the requirements of engineering applications.     

Q420GJ钢双丝埋弧焊接试验

通过双丝埋弧焊接工艺性能试验、焊接接头力学性能试验及组织结构分析等,对Q420GJ钢的焊接性能及相关组织结构进行了研究。结果表明:焊接接头综合力学性能优良,接头抗拉强度达到590MPa,焊缝-40℃冲击功平均值KV2达到119J;热影响区的韧脆转变温度在-30℃附近;焊接接头过热区组织为贝氏体,焊缝中含有较多的针状铁素体。     

Weldability of Low Carbon Transformation Induced Plasticity Steel

Transformation induced plasticity （TRIP） steel exhibited high or rather high carbon equivalent （CE） because of its chemical composition, which was a particularly detrimental factor affecting weldability of steels. Thus the weldability of a TRIP steel （grade 600） containing （in mass percent, %） 0.11C-1. 19Si-1.67Mn was extensively studied. The mechanical properties and impact toughness of butt joint, the welding crack susceptibility of weld and heat affected zone （HAZ） for tee joint, control thermal severity （CTS） of the welded joint, and Y shape 60° butt joint were measured after the gas metal arc welding （GMAW） test. The tensile strength of the weld was higher than 700 MPa. Both in the fusion zone （FZ） and HAZ for butt joint, the impact toughness was much higher than 27 J, either at room temperature or at -20 ℃, indicating good low temperature impact ductility of the weld of TRIP 600 steel. In addition, welding crack susceptibility tests revealed that weldments were free of surface crack and other imperfection. All experimental results of this steel showed fairly good weldability. For application, the crossmember in automobile made of this steel exhibited excellent weldability, and fatigue and durability tests were also accomplished for crossmember assembly.     

316L/X65双金属复合管焊接接头组织与性能

 采用钨极氩弧焊和手工电弧焊焊接316L/X65双金属复合管。利用光学显微镜、能谱仪、扫描电镜、力学性能测试及电化学测试等分析手段研究了复合管焊接接头的微观结构、化学成分、力学性能及电化学腐蚀性能。结果表明,过渡层焊缝的化学成分受到稀释较小,过渡层熔合线附近出现了元素迁移,不锈钢层焊缝与母材的化学成分基本一致;扩散层为类马氏体＋残留奥氏体,过渡层和不锈钢层焊缝均为奥氏体＋少量铁素体;在试验参数下,焊接接头各项力学性能优良、无缺陷;覆层焊缝与母材的电化学腐蚀性能相差极小。     

Influence of post-weld heat treatment on the microstructure and hardness of laser weld seams on hot-rolled TRIP 800 steel

The transformation induced plasticity (TRIP) steels effect occurs because of the martensitic transformation of retained austenite during plastic deformation,and it provides the steel with excellent strength and ductility.While welding remains a vital part of auto body manufacturing,the weldability of TRIP steels is problematic,and this prevents its adoption for many applications in the automotive industry.This present work studies the effects of welding and post-weld heat treatment on the microstructure of TRIP steels.It is found that the microstructures of the fusion zone and the heat affected zone (HAZ) are changed after high-temperature heat treatment.Hardness tests revealed that fusion zone hardness decreased with increasing of temperatures in the post-weld heat treatment on the laser weld seam.The rolling performance of the welding seam and the seam of post-weld heat treatment were also studied.     

汽车钢板点焊工艺的发展

通过文献调研分析了冷轧、镀锌及高强汽车板的焊接特点。采用普通点焊工艺,铁锌合金镀锌板比纯镀锌板点焊工艺窗口宽约30%,但预热后纯镀锌板焊接性能较好;FEA模拟Mn-Si系TRIP800钢的焊点十字拉伸强度明显高于Mn系DP450钢,但实际试验结果却明显较低;Mn系1.5mm规格的DP800钢在点焊电流11 000A及时间0.6s时,焊点拉剪试验以韧性特征为主,焊点拉剪力高于20kN。1 300MPa热成型钢点焊接头有一定软化倾向。不同种类高强钢的合金元素含量和生产工艺的不同,其焊接性能体现出较大差异。     

激光焊接过程监测及焊缝质量检测技术研究现状

阐述了在激光焊接过程中通过监控等离子体等光电信号、熔池和小孔状态来分析评估激光焊接质量、通过无损检测手段分析焊后焊缝内部应力集中和气孔等缺陷、通过计算机视觉技术在线检测焊缝表面缺陷三种检测焊接质量的检测原理及发展。介绍了几种已应用于激光焊接生产线的较为先进的计算机视觉检测焊缝质量的产品。分析了视觉检测技术应用于焊缝在线检测中存在问题及发展趋势。     

Characteristics of Welding Crack Defects and Failure Mode in Resistance Spot Welding of DP780 Steel

The mechanical properties of welded joints in resistance spot welding of DP780 steel were tested,and three dif-ferent types of welding cracks in welded joints were investigated by optical microscopy,scanning electron microscopy and electron back-scattered diffraction.Finally,the failure mode of the welded joints in shear tensile test was dis-cussed.It is found the shear tensile strength of welded joints can be greatly improved by adding preheating current or tempering current.The surface crack in welded joint is intergranular fracture,while the inner crack in welded joint is transgranular fracture,and the surface crack on the edge of the electrode imprint can be improved by adding prehea-ting current or tempering current.The traditional failure mode criterion advised by American Welding Society is no longer suitable for DP780 spot welds and the critical nugget size suggested by Pouranvari is overestimated.     

船用热轧钢板焊接性能研究

建立了热轧钢板焊接热影响区（HAZ）的连续冷却转变曲线（焊接CCT曲线）,以研究船用热轧钢板的焊接性能。根据所建立的焊接CCT曲线,选择了合理的焊接工艺对10mm厚的船用热轧钢板进行了手工电弧焊,并对焊后的焊接接头进行了宏观检验和X射线探伤、力学性能试验及冲击试验。借助金相显微镜和扫描电镜分析了CCT图中不同冷速条件下的显微组织和焊接接头的显微组织以及冲击断口形貌。试验结果表明：根据建立的焊接CCT曲线,所选择的手工电弧焊的焊接工艺是合理的,焊缝质量良好,焊接接头具有良好的综合性能。