Diffusion welding of components made of creep-resisting alloys: diffusion welding of titanium-based creep-resisting alloys (Part 2)

The efficiency of using diffusion welding for joining components of nickel creep-resisting alloys is confirmed. It is proposed that the mechanical properties can be improved, the extent of plastic deformation of components reduced, and softening of the welded nickel creep-resisting alloys prevented using nickel-based interlayers.     

Diffusion welding of nickel-based creep-resisting alloys

Special features of the diffusion welding of creep-resisting alloys were investigated to evaluate the possibilities and prospects of using these alloys in aviation engine construction.     

Laser welding of components of different thickness made of dissimilar metals

The results of investigations into laser welding of components of different thicknesses produced from dissimilar metals are presented. The experimental results show that uniform heating of the weld edges is achieved by producing welded joints with a bead on the thin wall component, with the height of the bead 3–4 times greater than the thickness of the component. Experiments were carried out to investigate pulsed laser welding of components of different thicknesses made of dissimilar metals. The experimental results confirm that the mutual melting of the beads takes place without lack of fusion defects and burning in the welded joints only when the optimum dimensions of the beads are adhered to.     

Effect of friction welding parameters and heat treatment on the quality of welded joints in creep-resisting deformable nickel alloys

Methods of friction welding creep-resisting deformable nickel alloys and heat treatment are investigated. Welding conditions are selected. The results of mechanical tests and the determination of short- and long-term strength and impact bending resistance are presented, and the data obtained in metallographic and fractographic studies of the welded joints are described.     

脉冲大电流扩散焊接Al-Li合金1420

采用脉冲大电流热加工技术焊接Al-Li合金1420.通过比较不同焊接工艺下的焊接产品,在最优焊接条件下获得了接头抗拉强度为母材强度75%的焊接接头.分析了接头微观结构及其对接头性能的影响,通过金相图片和扫描图片分析了接头处焊接点的形成过程,认为焊接过程实际可以分为由于微区熔化现象引起的焊接点高速形成阶段和围绕焊接点的原子扩散过程.脉冲大电流焊接过程由于焊接时间短,因而晶粒并没有发生二次生长.接头断口SEM照片显示,接头断裂方式为沿晶/穿晶混合断裂方式.     

Effect of welding methods on the structure and mechanical properties of welded joints in creep-resisting titanium alloys with different initial structural conditions

Problems of welding rotor components made of creep-resisting titanium alloys are investigated. Comparative tests of the effects of fusion welding and rotational friction welding (FW) on the structure and properties of welded joints in titanium alloys are carried out. The experimental results show that welded joints produced by rotational FW have a structure identical to the structure of the parent metal, and the heat-affected zone does not form at all. The optimum conditions of FW of creep-resisting titanium alloys are determined. Irrespective of the initial type of structure, these conditions result in the mechanical properties of the welded joint at a level of 0.9 of the properties of the parent metal.     

异种合金惯性摩擦焊的研究现状

文中针对钢与其他合金、铝合金与其他合金、钛合金与其他合金、高温合金与其他合金的惯性摩擦焊的研究现状进行了阐述。主要对惯性摩擦焊的工艺参数选取、端面设计、焊前预热、焊后热处理等研究内容进行了综述。并对异种合金惯性摩擦焊存在的问题进行了分析总结。结果表明,采用合理选择工艺参数、设计不同形状的端面、添加中间过渡层、焊前预热处理、焊后热处理等方法获得强度与母材相当、焊接质量较好的接头。建议在后续的研究中,结合数值模拟对异种合金惯性摩擦焊的工艺参数及端面设计进行优化,对接头的元素分布及新相形成的种类与数量进行调控,对焊接界面金属的流动行为进行深入研究,以获得具有综合性能较好的异种合金惯性摩擦焊接头。     

Pressure welding of dissimilar creep-resisting alloys and simulation of the effect of the geometrical parameters of the specimen on the localisation of plastic deformation in the pressure welding zone

Computer modelling is used to investigate the possibilities of increasing the quality of welded joints in pressure welding of dissimilar creep-resisting materials in the presence of a relief on one of the welded surfaces. It is shown that the quality of welded joints depends on the geometrical parameters of the welded specimen.     

TC4钛合金电子束焊接接头组织和性能

通过室温拉伸、室温缺口拉伸、显微硬度以及金相分析对TC4钛合金电子束焊接接头的显微组织和性能进行了研究。试验结果表明，用电子束焊接TC4钛合金可获得性能良好的焊接接头，其接头的抗拉强度不低于母材，焊缝的缺口敏感系数均小于1。焊缝区和热影响区的硬度均高于母材，焊缝组织是由较粗大的原始β相转变而成的α′相，即针状马氏体，热影响区组织为均匀且细小的针状马氏体和原始α相的混合物。     

Al-Mg(Sc,Zr)合金焊接接头组织与性能试验研究

对比了以Al-Mg及Al-Mg-Sc合金焊丝为填充材料,手工TIG法施焊的Al-Mg-(Sc,Zr)合金焊接接头微观组织特征及力学性能。结果表明,基材热影响区没有发生明显的再结晶现象,证明Al-Mg-(Sc,Zr)合金具有很强的抗焊接热软化能力;采用Al-Mg-Sc合金焊丝为填充材料时焊缝晶粒组织得到明显细化,提高了焊缝强度;熔合区形成的细小等轴晶层提高了基材与焊缝填充材料的结合力。采用Al-Mg及Al-Mg-Sc合金焊丝焊接时,Al-Mg-(Sc,Zr)焊接接头强度系数均大于0.90;但采用Al-Mg合金焊丝时,焊接接头屈服强度仅为188 N/mm2,而采用Al-Mg-Sc合金焊丝时,焊接接头屈服强度高达287 N/mm2,大大提高了Al-Mg-Sc合金焊接构件的许用强度。     

2A97铝锂合金激光焊接特性

对厚度为2.0 mm的2A97铝锂合金进行了无填丝的激光焊接试验.通过拉伸试验、显微硬度计、光学显微镜以及扫描电镜研究了不同焊接热输入(激光功率、焊接速度)下焊接接头组织和性能.结果表明,随焊接热输入的增加,焊接接头系数增大,该厚度下2A97薄板最佳的焊接热输入为0.9~0.95 kJ/cm,此时接头系数可达到0.8左右.焊缝中的柱状晶分布区是强度最低区域,随焊接热输入的降低,焊缝区域中粗大的柱状晶所占比例增大,同时有伴随大量气孔出现,导致接头系数降低.     

钛/铝异种金属搅拌摩擦焊搭接接头的组织结构

采用搅拌摩擦焊对TC1钛合金和LF6铝合金异种金属进行了搭接连接,研究了接头的微观组织结构.结果表明,当搅拌头旋转频率为1 500 r/min、焊接速度为60mm/min时,能获得焊缝成形良好、无孔洞和裂纹等缺陷的搭接接头,搭接处铝合金和钛合金充分混合,形成焊核区.焊核两侧进入铝合金中的钛合金在搅拌针的挤压下发生了弯曲...     

铝锌镁钪锆合金搅拌摩擦焊接头组织与性能

通过对铝锌镁钪锆合金热轧板进行搅拌摩擦焊接试验,对合金焊接接头的力学性能和焊接接头各个区域的微观组织进行了分析.结果表明,沿焊接接头焊缝横截面的显微硬度呈W形分布,硬度最高处位于焊核区,硬度最低处位于距焊缝中心12mm的热影响区,焊接接头焊接系数达到0.90;焊核区大小为1～2μm的再结晶等轴晶粒,基材中的析出相被破碎和部分溶解为细小的圆颗粒;热机影响区的晶粒发生了强烈的弯曲变形,晶内析出相由片状转变为短棒状;热影响区的晶粒发生了明显长大,析出相也明显粗化;焊接接头拉伸断口都发生在热影响区内.     

不同铝含量的氩弧焊310S耐热钢板材焊接接头力学性能分析

传统的310S耐热钢焊接板材在高温下长期使用将破坏其合金表面形成的致密保护性氧化膜,使其抗高温和耐腐蚀性能降低,从而限制了其在一些苛刻复杂环境下的应用。在310S耐热钢板材中增加铝元素含量将有效提高其焊接板材在高温条件下的力学性能。采用手工钨极氩弧焊对不同铝含量的310S耐热钢板材进行焊接,利用光学金相显微镜和电子探针(EMPA)对不同铝元素含量的310S耐热钢板材焊接接头在高温条件下的力学性能进行实验研究。研究结果表明:高铝元素含量的310S耐热钢板材具有与母材一样优良的高温力学性能。同时,加铝后310S耐热钢板材具有良好的焊接性能,且无宏观裂纹、夹渣、气孔等缺陷。     

Resistance welding of aluminium and aluminium alloys

Special features of the process of resistance welding of aluminium and its alloys and also equipment manufactured by the CEA and supplied by Weber Comechanics are described.     

不同焊接工艺对5083-H111铝合金MIG焊接接头力学性能的影响

通过拉伸、弯曲和硬度试验,研究不同焊接线能力和预热温度对5083-H111铝合金MIG焊焊接接头力学性能的影响。结果表明,在不同线能量和预热温度下,5083-H111铝合金(4mm)焊接接头的抗拉强度良好,均满足标准要求;在不同线能量和预热温度下焊接接头的弯曲性能良好;在不同线能量和不同预热温度下,接头各区域的硬度变化不大,且无明显软化现象。     

1561铝合金TIG深熔焊接头组织与力学性能

采用TIG深熔焊工艺,对1561高镁铝合金进行了焊接,并对接头的显微组织和力学性能进行系统分析.结果表明焊缝中无气孔和裂纹缺陷;打底焊道中部存在“∧”字形粗晶区,其上下部晶粒尺寸细小;双层焊经历第二道的盖面焊后,打底焊道晶粒明显长大,熔合区晶粒晶界发生重熔,焊缝软化现象仍有发生;焊缝和热影响区的显微硬度低于母材,但热影响区并没有表现出明显的软化现象.接头抗拉强度可达314 MPa,表明深熔焊工艺适合于1561高镁铝合金的焊接.     

Friction stir welding characteristics of two aluminum alloys

1　INTRODUCTIONFrictionstirwelding(FSW )isapromisingweld ingprocessthatcanproducehigh qualityandlow costjoints[1,2 ] .Especially ,itcaneliminatesomeweldingdefectssuchascrackingandporosityoftenassociatedwithfusionweldingprocesses[2 ,3] ,andthusissuitedtoweldheat treatablealuminumalloysthatarediffi culttofusionweld[4 ,5] .Recentstudiesonthemi crostructuralcharacteristicsandmechanicalpropertiesofthefrictionstirweldedjointshaveindicatedthatdifferentaluminumalloyshavedifferentFSWcharac teris…     

双层铝合金车体焊接结构设计

依照双层铝合金车体总体设计规范的要求,以车辆动态包络线作为车体断面设计的约束条件,进行车体的三维设计和详细结构设计,按照EN 15085的焊接标准要求优化双层铝合金车体焊接结构,同时对车体母材与焊接材料进行优化匹配。经车体静强度试验验证,优化后的焊接接头型式减少了车体大部件和车体总成的焊接变形,适合车体的模块化制造需求。通过计算车体静强度,证明250 km/h双层铝合金试验车体的强度符合EN 12663要求,产品的安全性、可靠性满足欧洲铁路客车强度规范。