DZ55钢级Ф102mm×9.19mm地质钻杆管体断裂原因分析

通过宏观分析、金相检验、化学成分分析、力学性能测试和扫描电镜微观分析对一DZ55钢级Ф102mm×9.19mm地质钻杆的断裂原因进行了分析。结果表明：因该地质钻杆管体外壁存在较多的螺旋状划痕和刮蹭痕迹造成应力集中,加之钻杆材料韧性较低,从而导致钻杆管体在钻进过程中于损伤处萌生裂纹,裂纹不断扩展最终发生脆性断裂。     

某井S135钢级钻杆挤扁原因

某井钻井作业时发生了多次钻杆挤扁现象。采用宏观观察、化学成分分析、力学性能试验、金相检验等方法对钻杆挤扁的原因进行了分析。结果表明:钻杆管体与卡瓦之间的啮合接触不均匀造成应力分布不均匀,当局部的接触应力超过了钻杆管体的屈服强度而使钻杆管体发生塑性变形挤扁,卡瓦牙板磨损较为严重是导致应力分布不均匀的主要原因。     

铝/钢异种材料搅拌摩擦焊研究进展

由于铝、钢的物理化学性质存在巨大差异,铝/钢的连接是焊接领域的难点问题。搅拌摩擦焊是低热输入的固态连接方法,能够有效控制铝/钢金属间化合物的生长,且搅拌针强烈的搅拌作用可增加铝/钢异种材料机械咬合程度,得到高质量的铝/钢焊接接头,铝/钢搅拌摩擦焊已经成为了焊接领域的热点问题。文中综述了铝/钢搅拌摩擦焊国内外研究现状,涉及到接头形式、焊缝成形、焊接工艺和力学性能,着重介绍了铝/钢搅拌摩擦焊接头的连接机制,并围绕铝/钢搅拌摩擦焊存在的两大问题,对铝/钢搅拌摩擦焊新技术进行总结,并进一步提出了铝/钢搅拌摩擦焊的基础研究方向。     

10钢/35CrMnSi径向摩擦焊接头的力学性能及组织特征

目的 研究10钢/35CrMnSi惯性径向摩擦焊接头的力学性能和组织特征。方法 通过对10钢/35CrMnSi进行惯性径向摩擦焊接试验,采用OM、超声检测、万能材料试验机及显微硬度仪对接头的微观组织及力学性能进行表征。结果 10钢/35CrMnSi惯性径向摩擦焊接头焊合区内未发现裂纹、夹渣、未熔合等焊接缺陷,焊合率100%;接头显微硬度分布呈现出中间高两头低的特征,平均剪切强度达520 MPa,略高于10钢母材;焊接界面为明显的“锯齿状”咬和,35CrMnSi侧的热影响区由细小马氏体和少量贝氏体组织,10钢侧形成了一层具有明显金属流线的塑性变形层,靠近焊接界面的塑性变形层为厚度约150 μm的细晶区,其组织为少量马氏体和铁素体。结论 采用惯性径向摩擦焊技术实现了10钢/35CrMnSi异种金属的高强连接。     

连续驱动摩擦焊接头的特征形貌和性能

通过引入接头形貌特征参量表征因子(取粘径比α=粘合区长度/原始直径,比例因子η=外缘热影响区宽度/中心热影响区宽度),研究了摩擦压力和摩擦时间等工艺参数对45号钢连续驱动摩擦焊接头的形貌及力学性能的影响。结果表明,随着摩擦压力的升高粘径比α先升高后降低,而比例因子η持续升高;当摩擦压力为60 MPa时,随着摩擦时间的延长粘径比α不断增大,而比例因子η则不断减小。当综合因子δ(δ=η/α)为1.15-1.31时摩擦焊接头的热输入量适中,接头的力学性能良好,可作为45号钢连续驱动摩擦焊接头良好焊接工艺规范的制定原则。     

铝合金与镀锌钢板回填式搅拌摩擦点焊机制

目的 研究铝合金与镀锌钢板回填式搅拌摩擦点焊界面组织演变机制与焊接工艺参数对力学性能的影响规律。方法 采用连续焊接和改变焊接工艺参数的方法,分析了焊具自摩擦对焊接温度和接头力学性能的影响。采用电镜研究了铝合金与镀锌钢板连接界面的显微组织分布和焊接工艺参数对焊接温度及接头力学性能之间的内在关系。结果 焊具的自摩擦及重复性预热影响焊具温度和接头力学性能,其作用远大于焊接工艺参数的影响。镀锌层阻止了被焊材料的直接接触而避免了大量金属间化合物的形成,镀锌层和铝合金反应生成固溶体组织,从而提高了铝合金与钢的焊接性。此外,液态的锌被挤出搅拌区,形成钎焊的连接机制,增大了接头连接面积和强度。最佳焊接工艺参数为：旋转频率1800 r/min,套筒下压量1.0 mm,停留时间3 s。在此焊接规范下,接头最大接头剪切强度为6.23 kN,且76.2%的焊点力学性能满足工业使用标准。结论 回填式搅拌摩擦点焊是实现铝合金与镀锌钢板高质量连接的可靠方式。     

铝 / 钢异种金属搅拌摩擦焊及其研究进展

铝/钢异种金属连接结构在国防领域和国民生产、生活中更加广泛应用的前提,是获得良好的接头综合性能,但铝/钢焊接时易出现裂纹、金属间化合物等,严重影响了焊接接头质量。摩擦焊作为一种低温高效的固相连接方法,在新材料连接、高性能装备制造等领域受到了高度重视。其中,搅拌摩擦焊由于其可焊接头形式丰富而被重点关注。从搅拌摩擦焊的接头形式、工艺参数、力学性能及界面组织4个方面,分别介绍了铝/钢搅拌摩擦焊的研究进展,为其深入研究提供依据。     

电磁场对高速钢与45钢感应摩擦焊接的影响

利用电磁场对金属材料产生的"场致效应",调节摩擦焊接表面的温度场,以改善异种金属摩擦焊接组织及性能.研究了外加电磁场对W6Mo5Cr4V2高速钢和45钢摩擦焊缝显微组织、合金元素扩散及焊接接头力学性能的影响.结果表明,摩擦加热阶段施加电磁场使45钢近缝区铁素体的数量减少;而在顶锻阶段施加电磁场,使45钢侧铁素体数量有所增多.同时,在顶锻阶段施加电磁场作用时,主要合金元素C、Cr、W的扩散区宽度明显增大.在顶锻阶段采用较短的电磁场施加时间和较低的感应电流强度,可以提高W6Mo5Cr4V2高速钢和45钢摩擦焊接头的抗拉强度.     

不锈钢与渗碳钢惯性摩擦焊接头的组织与性能

目的 研究0Cr18Ni12Mo2Ti不锈钢与20CrMnMo渗碳钢的惯性摩擦焊焊接接头的组织与力学性能。方法 通过金相、能谱分析、显微硬度、拉伸试验对焊接接头进行组织与力学性能分析。结果 焊接试样上0Cr18Ni12Mo2Ti不锈钢一侧飞边尺寸比20CrMnMo渗碳钢一侧飞边小;焊接接头熔合区仅为50 μm,熔合线附近元素扩散层很窄,其中0Cr18Ni12Mo2Ti不锈钢仍为奥氏体组织,20CrMnMo钢组织由铁素体与珠光体转变为马氏体与索氏体,20CrMnMo一侧热力影响区组织为细小的片状珠光体与铁素体;焊缝区的显微硬度为358HV,高于2种母材;焊接接头抗拉强度大于590 MPa,断后伸长率大于32%,断裂位置均在0Cr18Ni12Mo2Ti不锈钢母材一侧。结论 采用惯性摩擦焊工艺可实现不锈钢与渗碳钢的高强连接。     

φ127mmS135钻杆刺漏失效分析

采用宏观分析、化学成分分析、金相检验、断口分析和力学性能检测等方法并结合钻杆的受力和环境工况对φ127mmS135钻杆管体发生刺漏失效的原因进行了分析。结果表明：钻杆的刺漏失效形式为腐蚀疲劳失效;钻杆外表面存在腐蚀坑,在交变应力的恶劣工况作用下于腐蚀坑底部萌生疲劳裂纹并扩展,最终发生刺漏失效。     

The potential adaptation of stationary shoulder friction stir welding technology to steel

Stationary shoulder friction stir welding is a newly developed technique currently used for joining plates of relatively soft metals at different angular planes. The process is not currently applicable to steel, hence the present study was developed to investigate the theoretical and technical viability of stationary shoulder technology in DH36 steel. Aluminium welds were produced using both conventional rotating shoulder and stationary shoulder friction stir welding techniques, and steel welds were produced using only conventional friction stir welding techniques. The effects of stationary shoulder technology on both the microstructural evolution and resultant mechanical properties of aluminium have been evaluated so that the likely effects on steel could be predicted. In the aluminium welds, the stationary shoulder technique results in a distinct transition between stirred and unstirred material, contrasting to the gradual change typically seen in conventional friction stir welds produced with a rotating shoulder. An investigation of weld properties produced in DH36 steel has demonstrated that if the stationary shoulder weld technique was used, the microstructure likely to be formed, would be dominated by a bainitic ferrite phase and so would exhibit hardness and tensile properties in excess of the parent material. It is predicted that if the same abrupt transition between unstirred and stirred material observed in aluminium occurred in steel, this would lead to crack initiation, followed by rapid propagation through the relatively brittle weld microstructure. Hence, these findings demonstrate that without further design and process improvements, stationary shoulder friction stir welding is unlikely to be applicable to steel.     

Friction Interface Migration of Copper Alloy and Carbon Steel Dissimilar Metal Joints in Inertia Radial Friction Welding

The microstructure and mechanical properties of the copper and steel bimetallic welded joint were analyzed. Research results show there was a friction interface transferring phenomenon in inertia radial friction welding (IRFW). A secondary friction interface (SFI) appeared in welded joints of H90 copper brass/D60 steel rod. The SFI showed an abnormal transferring phenomenon. The formation mechanism of the SFI was analyzed under the condition of H90 copper/D60 steel dissimilar metals in IRFW. A new model and formation mechanism were issued and used to explain the unusual transferring phenomenon and characteristic in the views of three gradients: temperature gradient, deformability gradient (large or super plastic deformability), and microstructure gradients. The microhardness and element diffusion also supported our viewpoints about the SFI transferring and provided proofs for the transferring mechanism.     

大厚度无元素稀释表面保护层的摩擦焊敷工艺

采用20钢，1Cr18Ni9Ti不锈钢在低碳钢线材表面上进行了大厚度无元素稀释表面保护层的耗材摩擦焊敷工艺试验研究。探讨了摩擦界面的摩擦行为，述了耗材金属过渡的机理，分析了焊敷层的形貌，微观组织，显微硬度和组分的分布。研究表明，应用耗材摩擦焊敷工艺可以获得大厚度，无元素稀释，显微硬度分布均匀，固相连接的表面保护层；摩擦系统的热物理不对称性是耗材金属过渡的驱动力；耗材金属通过真实接触面向母材表面过渡，其行为遵循金属摩擦的焊合－剪切－犁削理论；耗材磨擦焊敷工艺具有细化焊敷层和热影响区组织的工艺特性。     

Failure analysis and appropriate design of drill pipe upset transition area

In recent years, the drill pipe failures often happen in the case of ultra deep well drilling and complex geological conditions drilling. One of the main failure types is the stress concentration at the upset transition area of the drill pipe. Based on the elastic–plastic mechanics, finite element theory, and application of numerical simulation analysis for the actual mechanical properties of three-dimensional simulation analysis of drill pipe in the well, the finite element analysis (FEA) model of 5″ API standard drill pipe is established. The mechanical characteristic of API standard drill pipe upset transition area is simulated, which can provide a reasonable reference for the optimization of the size of new types 5″ drill pipe upset transition as well as the practical application. Based on the simulation model, the factors affecting the stress distribution of the drill pipe upset transition area are obtained, and the new type of upset is developed.     

Microstructures and mechanical properties of friction stir welded dissimilar copper/brass joints

In this study, an experimental investigation has been carried out on microstructure and mechanical properties of friction stir welded copper/brass dissimilar joints. Effect of axial tool force to welding quality has been investigated under obtained optimal tool rotation rate and tool traverse speed conditions. The tool for the dissimilar copper/brass friction stir welding manufactured from X155CrMoV12–1 cold work tool steel with material number of 1.2379. The friction stir welding quality was investigated by welding surface inspections, microstructural studies, micro hardness measurements and tensile tests. The experimental studies have shown that constant axial tool force during pre‐heating and during welding process are very important. As a result, by using 2.5–3 kN of axial tool force during pre‐heating and 5.5 kN of axial tool force during welding process, copper/brass dissimilar joints with well appearance and higher mechanical strength can be obtained.     

Joint properties and their improvement of AISI 310S austenitic stainless steel thin walled circular pipe friction welded joint

This paper describes the joint properties and their improvement in thin walled circular pipe friction welded joint for an AISI 310S austenitic stainless steel. Pipes were welded with the combination of the same thickness and outer diameter by a continuous drive friction welding machine that has an electromagnetic clutch. Then, when the clutch was released, the relative speed between both specimens instantly decreased to zero. When the joint with a pipe thickness of 1.50 mm was made at a friction pressure of 120 MPa, the joining could be successfully achieved and that had 100% efficiency with the base metal fracture. However, the joining became difficult with decreasing pipe thickness, and it was not successful at a pipe thickness of 0.50 mm. On the other hand, when the joint with a pipe thickness of 0.50 mm was made at a friction pressure of 30 MPa, the joining could be successfully achieved, although that did not have 100% efficiency. Then, when the joint was made under a friction time of 0.6 s, i.e. the friction torque reached just after the initial peak, and a forge pressure of 60 MPa, it had 100% efficiency with the base metal fracture. However, when that was made with high forge pressure such as 120 MPa, the joining could not be achieved because the adjacent region of the weld interface had heavy buckling. To obtain the successful joining and 100% joint efficiency with the base metal fracture for the thin walled circular pipe, the joint should be made with opportune friction welding condition as follows: low friction pressure, a friction time of just after the initial peak of the friction torque, and a forge pressure of double value of a friction pressure.     

铝合金线性摩擦焊研究现状

线性摩擦焊作为一种新型的固相焊接技术,热输入低、焊接应力小,适合于铝合金的焊接。介绍了线性摩擦焊的工作原理,主要综述了铝合金线性摩擦焊数值模拟、微观组织和力学性能等3个方面的研究进展。在此基础上,着重介绍了摩擦压力、焊接时间及振动频率等工艺参数对铝合金线性摩擦焊微观组织和力学性能的影响,介绍了工艺参数对铝合金与不锈钢、纯铜、镁合金等异种金属线性摩擦焊微观组织、力学性能及金属间化合物种类和分布的影响。最后,对铝合金线性摩擦焊在数值模拟、接头性能及金属间化合物调控方面存在的不足进行了总结,并对其主要发展方向进行了展望。     

Crack resistance of austenitic stainless steel pipe and pipe welds with a circumferential crack under monotonic loading

This paper describes the experimental studies carried out on cracked austenitic stainless steel pipe and pipe welds under bending loads. Pipe welds were produced by gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW). Fracture resistance curves for pipe and pipe welds were compared. Results indicate that the fracture resistance of pipe and pipe weld (GTAW) is comparable but that of pipe weld (GTAW+SMAW) is inferior. Cracks do not deviate from their original plane during propagation as observed in the cases of carbon steel pipe and pipe welds. The fracture resistance of pipe welds does not depend on the loading histories to which it has been subjected prior to fracture test. Initiation and crack propagation were observed prior to the maximum moment. An existing limit load expression is applicable for the pipe base material but gives non‐conservative results for the pipe welds. Multiplication factors have been suggested for the pipe welds for evaluation of limit loads using the existing expression. Fracture resistance for the pipe and compact tension specimens have also been compared for base material and welds.     

20#钢连续驱动摩擦焊大变形及传热行为的有限元模拟研究

目的研究20~#钢连续驱动摩擦焊接过程工艺参数对焊接过程温度场和变形行为的变化规律。方法基于ABAQUS有限元软件二次开发环境,建立了20~#钢连续驱动摩擦焊接过程中的完全热-结构耦合模型。通过对比模拟和实验获得的焊接温度场、轴向缩短量和飞边形貌,对模型进行了验证。研究了工艺参数对摩擦焊接过程温度场与大变形行为和接头组织与性能的影响规律。结果在不稳定摩擦阶段,峰值温度出现在外表面附近。在稳定摩擦阶段,峰值温度稳定在距焊缝中心约2/3半径位置。接头温度的升高速度随着摩擦压力和转速的增大而增大,摩擦压力和转速对稳定阶段温度场的影响很有限;经过顶锻阶段之后摩擦面温度分布更加均匀,顶锻力越大在接头相同的位置温度越低,顶锻力越大轴向缩短量越大。结论所建立的完全热-结构耦合模型可以模拟20~#钢连续驱动摩擦焊接过程的塑性变形过程,在不稳定摩擦阶段,摩擦压力和转速对温度场和变形的影响较大。在稳定摩擦阶段,摩擦压力和转速对温度场的影响不显著。顶锻阶段轴向缩短量随着摩擦压力、转速和顶锻压力的增大而增加。