摩擦转速对Super304H/T92摩擦焊焊接接头性能的影响

利用连续驱动摩擦焊技术焊接Super304H/T92异种钢钢管,焊接接头具有良好的显微组织和力学性能。考察了摩擦转速对焊接接头的显微组织和力学性能的影响,随着摩擦转速增加,焊接接头晶粒尺寸没有明显变化,热影响区碳化物析出相的数量略微增加,显微硬度增大,冲击韧性逐渐降低;摩擦转速对拉伸断裂位置和拉伸强度没有影响。     

Nd:YAG激光微型焊接超薄FeCo-V磁性合金焊接强度的优化（英文）

为了优化激光焊接FeCo-V合金拉伸强度,建立数学关系,结合工艺参数如荧光灯电流、焊接速度、脉冲时间和位置,以预测激光束焊FeCo-V薄片拉伸强度。建立程序以提高焊接强度和增大产率。结果表明,脉冲时间和焊接速度对拉伸强度影响很大,焊接接头的拉伸强度随脉冲时间的延长而增大,并在2.25 ms时达到最大。而且,接头的拉伸强度随着焊接速度的减小而增大,并在125 mm/min时达到最大。脉冲时间的延长和焊接速度的减小导致有效峰能量密度减小,因此更耐焊。在较高的脉冲时间和较低的焊接速度时,因为在熔合区形成了凝固微裂纹而使得焊接接头的拉伸强度增大。     

核电站钢衬里内环C45钢套筒焊接工艺

在分析核电站钢衬里内环用C45钢焊接性的基础上,对C45钢与P265GH钢进行了焊接工艺评定,并对其焊接接头进行了无损检测、拉伸、金相和硬度试验。试验结果表明,采用药芯焊丝CO2气体保护焊,选用合适的焊接材料和焊接工艺参数,采用焊前预热、层间温度控制和焊后消氢热处理等工艺措施,焊接接头中未发现裂纹和不良组织,接头屈服强度和硬度满足设计要求,所制订的焊接工艺可用于核电站钢衬里内环C45钢套筒的焊接。     

提高高速钢焊接刀具结构强度的两次淬火法

本文研究了普通等温退火、N次循环退火、焊缝下加热淬火、超焊缝加热淬火和焊缝区两次淬火对W6Mo5Cr4V2高速钢和45钢摩擦焊接工具结构强度的影响,并以此得出强化焊接接头的最佳工艺方法。     

Microstructure and Properties of Friction Stir Welded Joints of Al-Mg-Sc Alloy Plates

采用搅拌摩擦焊对铝镁钪合金热轧板和冷轧-退火板进行焊接。测定焊接接头的硬度分布和拉伸力学性能,采用金相和透射电子显微技术分析焊缝区显微组织特征和力学性能的关系。结果表明,热轧板和冷轧-退火板搅拌摩擦焊焊接系数高达92%;焊接接头上焊核区硬度最低、拉伸断口位于焊核区;焊核区在热循环作用下发生部分再结晶导致的亚结构强化的减弱以及Al3(Sc,Zr)粒子共格强化作用的消失是搅拌摩擦焊焊核区强度下降的主要原因。     

搅拌摩擦焊工艺参数对6061铝合金抗拉强度的影响

采用搅拌摩擦焊技术实现了4 mm厚AA6061-T4铝合金板材的对接,研究了焊接速度和搅拌头旋转速度对焊缝成形、显微组织及接头拉伸强度的影响。结果表明:AA6061在较宽范围的焊接速度和旋转速度下可获得良好的成形且无明显的缺陷;焊核区细小的等轴晶是接头强度较高的主要原因,接头抗拉强度随着焊接速度和旋转速度的增大呈先增大后减小的趋势,当焊接速度为180 mm/min、旋转速度为1200 r/min时可得到接头强度为母材的95%;断口处存在局部的Mg2Si团聚。     

大截面钢/铝摩擦焊接头力学性能及显微组织分析

针对大截面铸态纯铝与Q235钢异种金属.采用连续驱动摩擦焊技术进行焊接试验,通过光学显微镜观察、电子探针分析、常温和高温拉伸性能及硬度测试,探讨了其焊接接头的微观组织和力学性能.研究表明,大截面铸态纯铝与Q235钢间具有良好的摩擦焊接性,焊接接头强度等于或高于铝基材;高温条件下,试样均断于铝端母材,抗拉强度随着温度的升高呈现出明显的下降趋势,而伸长率随温度升高而增大;焊接接头在近缝区发生了晶粒细化,在粘塑性层内发生了一定程度的原子扩散,形成扩散层.     

钛/不锈钢爆炸焊接接头退火性能的研究

通过拉伸试验，组织分析，断口形貌分析以及焊缝显微硬度的,研究了钛／不锈钢爆炸焊接接头强度及退火工艺对焊接接头强度的影响。结果表明，钛／不锈钢爆炸焊接界面结合强度高于纯钛；退火温度低于400℃，焊接接头的强度不降低，缺口强度约为530MPa；退火温度为500℃时，焊接接头的强度显著降低，缺口强度小于420MPa。     

焊后热处理对TC4钦合金线性摩擦焊接头组织和性能的影响

在前期焊接试验参数优化基础上,通过自行研制的线性摩擦焊机焊接了两组TC4钛合金试件,其中对一组试件焊后进行630℃x3h的热处理,然后对焊态和热处理态焊接接头的组织和力学性能进行了对比分析.结果表明.焊态下接头组织更为细小;热处理态接头组织中析出了次生a相,且晶粒发生球化长大现象,接头组织更加均匀.对两种接头在室温和400℃条件下进行拉伸试验,接头拉伸断裂位置均在母材处,且室温拉伸条件下热处理接头的抗拉强度和屈服强度均较焊态接头的高,高温拉伸条件下两种接头拉伸性能相差不大.400℃、570MPa条件下两种接头的持久时间均超过100h.     

热输入对DP600双相钢激光焊接接头力学性能的影响

通过焊接接头显微硬度和拉伸测试,研究了光纤激光焊接0.7 mm厚DP600双相钢在不同热输入下的力学性能。结果表明,不同热输入下的接头硬度分布规律基本相同,当热输入较大时,HAZ外侧出现软化,HAZ软化程度随热输入增大而增加,HAZ软化位置随热输入增大而与焊缝中心的距离逐渐增大。但HAZ软化基本不影响接头力学性能,不同热输入的接头拉伸试样均断裂在母材,接头强度与母材相当而伸长率略有下降。     

地质钻杆摩擦焊接头组织与性能

首次采用摩擦焊接工艺对地质勘探用钻杆的管体与接头进行了焊接试验。探讨了不同的热处理工艺条件对DZ60钢钻杆管体与40Cr钢接头摩擦焊接头组织与性能的影响,并与采用热墩粗工艺生产的钻杆管体组织与性能进行了对比。试验结果表明,采用摩擦焊接及焊后调质热处理工艺制造的DZ60地质钻杆焊接接头的常规力学性能指标均高于地矿部DZ60地质钻杆管材的技术标准规定的数值,并优于采用现行热墩粗工艺制造的钻杆管材的力学性能数值。同时发现,采用合适的焊后回火热处理温度,可以有效提高焊接接头的抗拉强度与屈服强度,使其各项力学性能达到DZ60钻杆管材的技术标准,从而有效减少地质钻杆摩擦焊接头焊后热处理工艺,降低制造成本。     

Effect of friction welding condition on joining phenomena and joint strength of friction welded joint between brass and low carbon steel

Abstract

This paper describes the effect of friction welding condition on joining phenomena and joint strength of friction welded joints between copper–zinc alloy (brass) and low carbon steel (LCS). When the joint was made at a friction pressure of 30 MPa with a friction speed of 27·5 s^?1, brass transferred to the half radius region of the weld interface on the LCS side. Then, transferred brass extended towards the almost whole weld interface with increasing friction time. The joint efficiency increased with increasing friction time, and then the joint obtained 100% and the brass base metal fracture when the joint was made with a friction time of 4·2 s or longer. However, the fact that all joints had some cracks at the periphery portion of the weld interface was due to a deficiency of transferred brass at the periphery portion on the weld interface of the LCS side. On the other hand, brass transferred to the peripheral region of the weld interface on the LCS side, and then transferred towards the entire weld interface when the joint was made at a friction pressure of 90 MPa with a friction speed of 27·5 s^?1. The joint efficiency increased with increasing friction time, and it reached 100% at a friction time of 1·5 s or longer. In addition, all joints fractured from the brass base metal with no cracking at the weld interface. To obtain 100% joint efficiency and the brass base metal fracture with no cracking at the weld interface, the joint should be made with opportune high friction pressure and friction time at which the entire weld interface had the transferred brass.     

Friction welding of Al–Mg–Si alloy to Ni–Cr–Mo low alloy steel

Abstract

It is difficult to weld the dissimilar material combination of aluminium alloys and low alloy steels using fusion welding processes, on account of the formation of a brittle interlayer composed of intermetallic compound phases and the significant difference in physical and mechanical properties. In the present work an attempt has been made to join these materials via the friction welding method, i.e. one of the solid phase joining processes. In particular, the present paper describes the optimisation of friction welding parameters so that the intermetallic layer is narrow and joints of acceptable quality can be produced for a dissimilar joint between Al-Mg-Si alloy (AA6061) and Ni-Cr-Mo low alloy steel, using a design of experiment method. The effect of post-weld heat treatment on the tensile strength of the joints was then clarified. It was concluded that the friction time strongly affected the joint tensile strength, the latter decreasing rapidly with increasing friction time. The highest strength was achieved using the shortest friction time. The highest joint strength was greater than that of the AA6061 substrate in the as welded condition. This is due to the narrow width of the brittle intermetallic layer generated, which progressed from the peripheral (outer surface) region to the centreline region of the joint with increasing friction time. The joints in the as welded condition could be bent without cracking in a bend test. The joint tensile strength in the as welded condition was increased by heat treatment at 423 K (150° C), and then it decreased when the heat treatment temperature exceeded 423 K. All joints fractured in the AA6061 substrate adjacent to the interface except for the joints heated at 773 K (500° C). The joints fractured at the interface because of the occurrence of a brittle intermetallic compound phase.     

Joining phenomena and joint strength of friction welded joint between pure aluminium and low carbon steel

Abstract

This paper describes the joining phenomena and joint strength of friction welded joints between pure aluminium (P-Al) and low carbon steel friction welds. When the joint was made at a friction pressure of 30 MPa with a friction speed of 27·5 s^?1, the upsetting (deformation) occurred at the P-Al base metal. P-Al transferred to the half radius region of the weld interface on the low carbon steel side, and then it transferred toward the entire weld interface. When the joint was made at a friction time of 0·9 s, i.e. just after the initial peak of the friction torque, it had ～93% joint efficiency and fractured on the P-Al side. This joint had no intermetallic compound at the weld interface. Then, the joint efficiency slightly decreased with increasing friction time. The joint had a small amount of intermetallic compound at the peripheral region of the weld interface when it was made at a friction time of 2·0 s. When the joint was made at a friction time of 0·9 s, the joint efficiency decreased with increasing forge pressure, and all joints were fractured at the P-Al side. Although the joint by forge pressure of 90 MPa had hardly softened region, it had ～83% joint efficiency. To clarify the fact of decreasing joint efficiency, the tensile strength of the P-Al base metal at room temperature was investigated, and the tensile test was carried out after various compression stresses and temperatures. The tensile strength of the P-Al base metal has decreased with increasing compression stress at any temperature. Hence, the fact that the joint did not achieve 100% joint efficiency was due to the decrease in the tensile strength of the P-Al base metal by the Bauschinger effect. To obtain higher joint efficiency and fracture on the P-Al side, the joint should be made without higher forge pressure, and with the friction time at which the friction torque reaches the initial peak.     

Mechanical evaluation and thermal modelling of friction welding of mild steel and aluminium

In friction welding of two dissimilar materials, two rods are welded together by holding one of them still while rotating the other under the influence of an axial load which creates frictional heat in the interface. In this study, mechanical properties of mild steel and aluminium welded rods were evaluated to understand the thermal effects, and an explicit one-dimensional finite difference method was used to approximate the heating and cooling temperature distribution of the joint. The thermal effects of the friction welding were observed to have lowered the welded materials hardness compared to the parent materials. The tensile strength of the welded rods is lower than the parent rods due to incomplete welding. The preliminary predictions were compared to actual thermocouple data from welds conducted under identical conditions and were shown to be in fair agreement. The finite difference method proposed in this work will provide guidance in weld parameter development and will allow better understanding of the friction welding process.     

7A04铝合金/304不锈钢连续驱动摩擦焊及焊后热处理

对7A04铝合金与304不锈钢异种材料进行了摩擦焊接试验,并对接头进行了不同温度、不同时间的退火处理.对接头飞边形貌、抗拉强度、断口形貌、金相组织、显微硬度等进行对比分析.结果表明,采用合适的工艺参数能获得形貌良好的飞边和更好的抗拉强度,焊合区的铝合金组织发生动态再结晶,晶粒细化,组织比基材更加致密,结合面两边互有元素扩散,焊合区显微硬度高于基材.经400℃×3 h退火处理的接头其抗拉强度提升明显,界面形成了不同的金属间化合物,扩散层厚度略有增加,显微硬度值有所下降.     

铜对钢/铝激光-MIG复合焊接头组织及性能的影响

采用激光-MIG复合焊方法研究了铜对SYG960E超高强度度钢/6061铝合金焊接接头微观组织及力学性能的影响.结果表明,与MIG焊相比,激光-MIG复合焊有利于改善焊缝成形及焊接质量.钢/铝界面层具有双层结构,靠近铝焊缝侧为针状的FeAl₃金属间化合物,而靠近钢母材侧为条状的Fe₂Al₅金属间化合物.铜对钢/铝界面层及接头的力学性能具有显著的影响.添加铜后可以有效地减小界面层厚度和裂纹敏感性,降低钢/铝接头的最高硬度,明显提高接头的抗拉强度,接头强度可以提高110%,这主要与铜抑制界面层生长和改善界面层中Fe-Al金属化合物的脆硬性有关.     

Joining phenomena and joint strength of friction welded joint between aluminium–magnesium alloy (AA5052) and low carbon steel

Abstract

The joining phenomena and the joint strength of an Al–Mg alloy (AA5052) and low carbon steel (LCS) friction welded joints were investigated. The weld interface of the LCS side at a friction time of 1·2 s had a slightly transferred AA5052, and then the entire weld interface had it at a friction time of 3·0 s or longer. The joint efficiency increased with increasing friction time, but it decreased at a friction time of 12·0 s or longer. The joint at a friction time of 3·0 s with forge pressure of 190 MPa had 100% joint efficiency and the AA5052 base metal fracture with no crack at the weld interface. The weld interface of these joints also had no intermetallic compound. On the other hand, the joint at a friction time of 8·0 s, which had ～97% joint efficiency, fractured between the AA5052 side and the weld interface because it had the intermetallic compound at the weld interface.     

热处理工艺对M390/304 CMT焊接接头微观组织及力学性能的影响

基于改善M390高碳马氏体不锈钢与304奥氏体不锈钢焊接接头的力学性能特别是提高焊接接头硬度,以达到高端刀具生产的要求,对冷金属过渡焊接M390高碳马氏体不锈钢与304奥氏体不锈钢获得的焊接接头进行不同工艺的热处理研究.采用拉伸、维氏显微硬度测试及扫描电镜(SEM)表征不同热处理工艺的焊接接头力学性能及微观组织演变,统计了不同热处理工艺下焊接接头中M390母材、M390细晶区和M390粗晶区等区域的碳化物分布,研究了不同热处理工艺下焊接接头的断裂机理.研究结果表明,在1 150℃水淬热处理工艺下焊接接头既满足刀具钢硬度的要求,又具有良好的力学性能,可以作为M390/304焊接接头的最佳热处理工艺,对应焊接接头的抗拉强度和断后伸长率为502 MPa和20.8%,抗拉强度和断后伸长率分别是焊态的98%和95%. 1 150℃水淬热处理工艺的M390母材、细晶区和粗晶区中碳化物平均尺寸最小,碳化物形貌以细小的块状均匀分布.淬火温度升高,抗拉强度和断后伸长率均呈现出先下降后升高的趋势,随着冷却速度的减小,抗拉强度和断后伸长率均呈现出下降的趋势.不同热处理工艺下焊接接头的断裂位置在M390粗晶区...     

TC17钛合金线性摩擦焊接头组织及力学性能分析

针对固溶时效态TC17钛合金焊态及焊后热处理态线性摩擦焊接头,进行显微组织及力学性能对比分析. 结果表明,焊态时焊缝组织发生了回复与再结晶,由于焊后冷却速度较快,生成了亚稳定β相,焊缝区发生了软化;热力影响区组织沿受力变形方向拉长、细化、交替呈带状分布,加工硬化程度较高,显微硬度明显高于其它区域;热影响区由于二次次生α相基本溶解于亚稳定β相,导致显微硬度显著降低. 经过焊后热处理,亚稳定β相发生时效分解,析出了弥散程度更高的针状次生α相使得焊接区硬度大幅度提高. 由于亚稳定相的生成,焊态接头发生软化,拉伸均断裂在焊缝区,抗拉强度达到母材强度91.8%,断口呈脆性断裂形态;焊后热处理态接头由于二次次生α相的析出,起到弥散强化的作用,拉伸试验均断在母材,断口呈典型韧性断裂形态.