超声无损检测技术在金属材料焊接缺陷检测中的应用

金属材料的焊接在各行各业中具有广泛应用,随着现代工业和技术手段的不断发展,金属材料焊接的质量不断提高。但是,焊缝中仍然不可避免的会出现裂纹、夹渣、气孔、未融合等焊接缺陷,直接影响了工件的质量和使用寿命。基于超声波无损检测技术的金属材料焊接缺陷检测具有缺陷检出率高、检测精度高、效率高的特点。本文在分析超声无损检测技术的基础上,采用衍射时差法(TOFD)对焊缝缺陷进行定性与定量分析,从而为金属材料焊接缺陷提供一种有效的技术手段。     

冷轧激光焊机焊缝质量判定系统的应用

早期冷轧激光焊机焊缝质量的判定,一般采用人工肉眼观察、在线视频跟踪、离线破坏测试等方法.由于上述焊缝质量标准缺乏量化标准,不仅识别准确性差且效率低,无法满足高速生产的要求.随着视觉技术的不断发展,冷轧激光焊机通过焊缝特征数据采集和数学模型分析,已实现焊缝同步自动判定功能.详细介绍了先进视觉技术在冷轧激光焊机的应用,着重分析了系统组成,焊缝间隙、焊接熔深、焊缝轮廓等焊缝特征数据采集的方法,并通过具体案例应用分析,阐述了判定系统的高效与准确性.当前焊机通过该判定系统的应用,提高了焊接可靠性,有效降低了机组焊缝断带风险.     

激光电弧复合焊接用于27SiMn板材焊接的工艺研究

本文采用激光电弧复合焊接技术进行27SiMn板材的对拼焊接,对焊接件进行力学检测、超声波检测、金相分析,结果表明:焊接坡口熔化良好,未发现气孔、裂纹等缺陷;焊缝未见有害组织,且存在大量铁素体;焊缝硬度值均高于母材,尤其是钝边区域的硬度高达410HV_1;焊缝强度及冲击性能均优于母材部位。且与传统CO_2电弧焊接方式相比,激光电弧复合焊接技术工序更为简便,焊接速度更快,热变形更小。     

米巴赫焊机设备功能精度的维护措施

米巴赫激光焊机是实现冷轧带钢厂的各条生产线连续生产的关键设备之一,它具备其他焊接方法无法比拟的优越性,能够显著提高轧制和焊缝的可靠性以及降低断带率。带钢激光焊接质量主要取决于焊接速度、焊接功率、离焦量(FOCUS)、工作头压力、操作侧驱动侧间隙(GAP)、二次剪切、预加热和后退火等主要参数和功能的控制精度。以首钢京唐二冷轧酸轧生产线的米巴赫激光焊机为研究对象,结合QCDS焊缝检测系统的有效使用,总结提出通过提高激光焊机设备功能精度保证焊缝质量的系列维护技术措施,明确了焊机使用维护中的关键点和技术规程,并取得显著应用效果。研究可为其他机组快速诊断由于设备功能精度引起的焊缝质量不良的原因提供参考。     

退火功能在TMEIC激光焊机上的应用及提高焊缝质量措施

通过安钢冷轧厂1 550 mm酸轧机组位于入口处的TMEIC激光焊机生产实例,论述了激光焊机工作原理和焊缝溶化再结晶过程中微观织构变化,分析了影响带钢焊缝质量的因素.通过建立带钢焊接前的预告制度、采用焊机喂丝系统、BULGE试验设备焊缝检测等几项措施,提高焊缝质量,保证了生产的连续性.     

全自动超声波检测技术在碳钢管线焊缝检测中的应用

全自动超声波检测技术(AUT)以其高效、精确、环保等优势,成为碳钢管线焊缝的首选检测方法。然而由于AUT扫查装置几何条件限制,难以应用于管径114.3mm(4寸)及以下规格管线的检测。然而,由于地下资源开发逐渐向更深区域进行,4寸海管的应用也越来越广泛。对此,为验证AUT检测技术是否可以在碳钢管线中应用,本文加工了5条管径114.3mm(4寸),壁厚6.4mm的薄壁焊缝,每条焊缝加工5个人工缺陷,累计25个人工缺陷,缺陷位置涵盖焊缝的根部、填充和盖面区域。应用AUT检测技术分别进行检测、数据分析、宏观切片。最终通过对比分析AUT检测数据和宏观切片数据,以评定在管径114.3mm的(4寸)工件中,AUT检测技术的缺陷检测能力及高度定量精度。     

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。     

激光焊接技术在金属结构修复中的应用

激光焊接是现代制造业中较为重要的结构修复技术之一,激光焊接修复技术的发展对提高金属结构的可靠性和使用寿命有着极为重要的意义。分别分析激光焊接技术在金属表面结构和内部结构上的应用,描述了焊缝跟踪、修复操作、修复质量等具体应用过程,展望了激光焊接修复技术在金属结构中的应用前景。     

冷轧硅钢酸洗机组闪光焊机焊缝缺陷预防及故障处理

以本钢冷轧硅钢酸洗机组闪光焊机(日本某公司)为例,围绕如何保证带钢焊缝的质量,讨论了生产中焊缝缺陷预防及故障处理的问题。主要从焊缝缺陷产生原因及预防措施、焊接操作注意事项、光整刀的高度在线调整、离线调整几个方面总结了焊缝缺陷产生原因及预防措施;讨论分析10余种常见焊接事故的原因及避免措施;并对常见的5种硅钢焊缝质量原因及预防方法进行了分析总结。     

酸轧机组钢带激光焊接接头断带故障分析

针对冷轧酸轧机组激光焊接接头断带故障,观察了焊接未熔合、焊接气孔以及焊缝氧化等缺陷的形貌特征,并对断带原因进行了分析。结果表明：焊接缺陷是造成断带的主要原因,其中对接间隙、焊接线能量及焦点位置等工艺参数不当是造成焊接未熔合的主要原因,保护气体参数设置不当是造成焊接气孔及焊缝氧化等缺陷的主要原因。     

TC4钛合金线性摩擦焊接头组织及性能研究

采用XMH-160型线性摩擦焊机焊接TC4钛合金板材,观察了焊接接头形貌及焊缝组织,测试了焊接接头的力学性能.结果表明,TC4钛合金适于采用线性摩擦焊接,焊接接头的室温拉伸性能、冲击韧性和高周疲劳性能不低于母材.其线性摩擦焊接头大致可以分为焊缝区和塑性变形区两个区域,焊缝区域原始组织被破碎,晶粒细小;塑性变形区域原始片层组织被压扁拉长,与焊接振动方向呈近平行的流线状.     

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。     

金刚石锯片的激光焊接工艺

采用水平对焊的方式实现了孕镶金刚石锯片刀头与钢基间的高强度激光焊接,研究了激光焊接工艺参数对金刚石锯片焊接质量的影响,激光焊接工艺参数包括：光束模式、激光功率,焊接强度,离焦量,等离子体控制和光束偏离量。试验结果表明,光束模式,激光功率,焊接强度,离焦量,等离子体控制能显著影响激光焊接深度;光束偏离量则会影响焊缝中的气孔数量。     

800 MPa级TRIP钢窄搭接焊接工艺研究

通过杯突试验、表面质量观察、焊缝金相组织分析,研究了800MPa级TRIP钢的焊接工艺性能。实验结果表明,焊接前无需预热处理;随着焊接电流的降低,焊缝表面起皮缺陷减轻;采用低电流、低焊接速度的合理匹配,并投入后退火工艺,焊缝熔合线区金相组织为贝氏体,可获得合格的杯突试验和优异的焊缝表面质量;试验钢焊接工艺选择与普材搭接焊接可获得最佳焊缝质量焊缝。     

Simulation of the forming of mash seam welded sheets

The paper presents results on the optimization of the process of mash seam welding for improving the formability of the joined sheet metal semi-products. An integrated concept including the welding, smoothing and heat treatment of mash welded sheets has been developed. As an example, fatigue tests and the simulation of the forming behaviour of a mash seam welded tensile specimen simulated by the finite element method (FEM) is discussed. The determination of the material properties of the seam which, so far, have been determined experimentally is thus considerably simplified.     

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.     

Increasing Rigidity and Strength using Local Effects of Bead‐on‐Plate Laser Welding Seams

In order to achieve graded strength properties and to improve the rigidity of metallic materials, side effects of the laser joining process are used. Local physical and geometrical effects which have only been observed as side effects are to be used purposefully. The investigations take place in context of the SFB 675 “high‐strength metallic structures and joints by setting up scaled local material properties”. The energy needed to produce bead‐on‐plate welding seams can be limited to a small area of the workpiece by using a focused laser beam with a diameter of tenths of a millimetre. The heat affected zone of a laser beam is very small. In comparison to other welding procedures, lower heat input is the main reason that basic material characteristics remain unaffected after welding. The progressive development of laser beam sources to higher available laser output power has extended their spectrum of use in the field of joining technologies [1, 2]. It should be pointed out that local physical and geometrical effects can be used to achieve specific material characteristics. Bead‐on‐plate laser welding seams were produced to demonstrate that strength and rigidity can be increased in metal sheets. First investigations are carried out on the micro‐alloyed high‐strength steel H340LAD. The sheets were tested using tensile tests and also with 3‐point and 4‐point bending tests. Six different specimens were investigated, one without welding seams and five with different laser based welding seam types. The tensile and bending tests showed that higher forces were needed to rupture or to bend the laser welded specimens. Furthermore, the investigations showed that the strength of the specimens was increased in comparison to the specimens without welding seam.     

CO2 Corrosion and Grooving Corrosion Behavior of the ERW Joint of the Q125 Grade Tube Steel

In order to investigate the CO2 corrosion behavior and the grooving corrosion susceptibility of electric resistance welded tubes of the Q125 grade,the high temperature and high pressure autoclave was employed to conduct CO2 corrosion experiments for the welded joint.The mechanisms of grooving corrosion and the factors influencing grooving corrosion susceptibility were identified by electrochemical measurement,microstructure observation,residual stress examination,micro-region composition and orientation analysis.The CO2 corrosion results show that the corrosion resistance of the base material is the best,followed by heataffected zone and the welded seam is the worst.The grooving corrosion occurred in the welded seam,and the grooving corrosion susceptibility of welded seam is relativity high.The dominated reason for the grooving corrosion of the electric resistance welded joint is the notable inclusions consisting of Mn S as the main content in the welded seam.The proportion of high-angle grain boundaries in the welding zone is higher than that of base metal and the heat affected zone,which plays an important role in the corrosion behavior of the welded seam.     

垫板法埋弧焊在天车梁制作中的应用

16mm厚Q345D钢板不需开坡口,双面单层埋弧焊接,成功地焊接了天车梁腹板的一级对接缝,生产效率提高,焊缝质量良好。     

7003铝合金TIG焊焊接接头的组织与性能

采用显微硬度及电导率测试,剥落腐蚀及电化学腐蚀试验,光学显微镜(OM)及透射电镜(TEM),研究经ER5356焊丝钨极氩弧焊(TIG)的7003铝合金型材焊接接头各部分的微观组织与性能。结果表明:在离焊缝中心30 mm左右的热影响区位置形成硬度较低的软化区,这是由于η′(Mg Zn2)相的长大粗化;焊接接头的耐蚀性依次为焊缝区过时效区母材区淬火区,其原因是淬火区的晶界析出相连续分布,形成连续阳极腐蚀通道,增大了应力腐蚀及剥落腐蚀倾向,使得腐蚀性能很差;而过时效区和母材区的晶界析出相不连续,耐蚀性较好。