Effect of Annealing on Fly-Line Microstructure and Properties of Explosively Composited Stainless Steel-Stainless Steel Plates

Effect of annealing on "fly-line"(adiabatic sheer line) microstructure and properties of explosively composited stainless steel-stainless steel plates was studied.Results show that the flyline microstructure will diminish through certain annealing process,while the cracks formed from fly-line microstructure will remain.Therefore,fly-line microstructure can be considered as a plastic deformation microstructure and crack source s meanwhile its formation is considered as a special plastic deformation mechanism of metal under explosive load.

Effect of heat treatment on the microstructure and mechanical properties of structural steel–mild steel composite plates fabricated by explosion welding

Two dissimilar steel plates,structural steel and mild steel,were joined by explosion welding to form a composite.The composite was then heat-treated by quenching at 840℃ for 30 min followed by tempering at 200℃ for 3 h.The microstructure was investigated under an optical microscope and a scanning electron microscope.The mechanical properties were measured using Vickers microhardness and Charpy impact tests.The results show a deformed interface with typical wave features at the welding zone,but no defects were observed.Moreover,the ferrite in the parent plate in the weld zone was elongated due to the strong plastic deformation from the explosion.After heat treatment,the hardness of the flyer plate(structural steel)was over HV0.2800,while that of the parent plate(mild steel)was HV0.2200.The increase in hardness was due to the presence of martensite.Moreover,the average impact energy was increased from 18.5 to 44.0 J following heat treatment;this is because of the formation of recrystallized grains at the weld interface,which is due to the dynamic recovery and local recrystallization,and the strong elemental diffusion that occurred between the two plates.

Influence of flash trap profiles on joint properties of friction welded CP-Ti tube to 304L stainless steel tube plate using external tool

Titanium tube and stainless steel tube plate were welded by an innovative friction welding of tube to tube plate using an external tool (FWTPET). Copper was used as an interlayer for joining the dissimilar materials and also to minimize the effect of intermetallics formed at the joint interface. The process parameters that govern FWTPET process are plunge rate, rotational speed, plunge depth, axial load and flash trap profile. Among them, the flash trap profile of the tube has a significant influence on the joint integrity. Various flash trap profiles like vertical slots, holes, zig-zag holes, and petals were made on the titanium tube welded to the stainless steel tube plate. Macroscopic and microscopic studies reveal defect-free joints. The presence of copper interlayer and intermetallics was evident from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) studies. The microhardness survey was presented across and along the interface. A novel test procedure called “plunge shear test” was developed to evaluate the joint properties of the welded joints. The highest shear fracture load of 31.58 kN was observed on the sample having petals as flash trap profile. The sheared surfaces were further characterized using SEM for fractography.

Overview of stainless-steel clad-plate welding

Types of bimetal clad plate, manufacturing methods, and their fields of application were summarized. In particular,key aspects of the welding of clad-rolled stainless steel were described, including the weldability of the base and clad metals, design criteria for the transition layer, the selection of the type of welding process and consumables used, types of blanking and welding bevels, preparation and assembly prior to welding, welding procedure requirements, post-weld cleaning and heat treatment, and welding quality inspection. This paper will serve as a reference for the welding technology used in future consumer applications in related fields.

Performance analysis of the SAW joint of duplex stainless steel clad plate

Duplex stainless steel clad plate exhibits good performance and is relatively inexpensive,however,some difficulties must be overcome when welding different materials. In this study,submerged arc welding（ SAW） was used to weld Baosteel ship clad plates（ 2205 ＋ DH36）,and the performance of the welded joints was tested. The results indicate that the mechanical properties and the corrosion resistance of the welded joints meet the required specifications. The distribution of the main anti-corrosive elements and the phase ratio of the welded joint are analyzed,thereby indicating excellent uniformity and confirming that the welded joint is corrosion resistant.

Gas metal arc welding of duplex stainless clad steel plates

The 2205 duplex stainless ＋ DH36 clad steel plate was welded by gas metal arc welding（GMAW）, and the welding performance of the clad steel plate was investigated. The results show that the adaptability of the welding procedure for the base metal of carbon steel, the transition layer, and the cladding material is excellent. The test results indicate that the phase proportion and component dilution of the GMAW-welded joints of clad steel plate can be effectively controlled to yield joints with good mechanical properties and corrosion resistance.

Comparison of explosive welding of pure titanium/SUS 304 austenitic stainless steel and pure titanium/SUS 821L1 duplex stainless steel

Pure commercial titanium was welded with two types of stainless steel,namely SUS 304 austenitic stainless steel and SUS 821L1 duplex stainless steel.The wavy interface of SUS 821L1 was smaller than that of SUS 304.The vortex zone was observed from both longitudinal and transverse directions,and its composition was analyzed.The interface of Ti/SUS 821L11 was able to bear 401−431 MPa shear load while that of Ti/SUS 304 could withstand 352−387 MPa.The weldability window was used to analyze experimental phenomenon.Furthermore,the smoothed particle hydrodynamics(SPH)numerical simulation method was used to simulate the wavy interface.The trend of wavelength and amplitude change with strength and the stand-offs was consistent with the experimental results.

Microstructure,strength and welding window of aluminum alloy-stainless steel explosive cladding with different interlayers

Aluminum 5052(Al 5052)-stainless steel 316(SS 316)plates were explosively cladded with Al 1100,pure copper and SS 304 interlayers.The operational parameters viz.,standoff distance,explosive mass ratio(mass ratio of the explosive to the flyer plate)and inclination angle were varied and the results were presented.The advent of interlayer relocates the lower boundary of the welding window,and enhances the welding regime by 40%.A triaxial welding window,considering the influence of the third operational parameter,was developed as well.Use of interlayer transforms the continuous molten layer formed in the traditional Al 5052-SS 316 explosive clad interfaces into a smooth interface devoid or with a slender presence of intermetallic compounds.The microhardness,ram tensile and shear strengths of the interlayered clads are higher than those of the traditional explosive clads,and the maximum values are witnessed for stainless steel interlaced Al 5052-SS 316 explosive clads.

Thermal fatigue behavior of copper/stainless steel explosive welding joint

Thermal fatigue performance of copper/stainless steel explosive welding joint was investigated by using a highly effective thermal fatigue test device. The testing device adopted induction coil to heat and carry out two groups of thermal fatigue test at the same time. Metallurgical microscope and scanning electron microscope were used to respectively measure the surface crack and cross-section crack propagation morphology of the explosive welding joint specimen that were conducted thermal cycling for different upper limit temperatures and different cycle time.Experimental results indicated that the cyclic thermal stress and oxidation corrosion was the major factors for fatigue damage behavior of explosive welding joints, where the oxidation corrosion of the interface has become more serious with the increasing the upper limit temperature or the number of cycles rising. Thermal fatigue cracks initiation was mainly beginning from the wavy interface between copper and stainless steel, the vortex-like cast microstructure formed by explosive welding can prevent the crack from propagating along the interface edge and change the direction of crack propagation.The initiation and expansionof thermal fatigue cracks were observed in the copper matrix.

Study on numerical simulation of TA1-304 stainless steel explosive welding

In order to guide the explosive welding experiment of titanium-stainless steel,Three-dimensional numerical simulation of explosive welding,which select TA1 as flyer plate and 304 stainless steel as base plate,is carried out by using the LS-DYNA software and SPH-FEM coupling algorithm in the present study.The explosive welding window is calculated and established.It is found that the numerical simulation results are in good agreement with the experimental results.The displacement,velocity and pressure-time curves of characteristic elements show that the quality of explosive welding composites is superior.It is proved that SPH-FEM coupling algorithm is effective for explosive welding of TA1/304 stainless steel and can effectively guide the selection of explosive welding parameters.

Investigation on the explosive welding mechanism of corrosion-resisting alu-minum and stainless steel tubes through finite element simulation and experi-ments

To solve the difficulty in the explosive welding of corrosion-resistant aluminum and stainless steel tubes, three technologies were proposed after investigating the forming mechanism through experiments. Then, a 3D finite element model was established for systematic simulations in the parameter determination. The results show that the transition-layer approach, the coaxial initial assembly of tubes with the top-center-point the detonation, and the systematic study by numerical modeling are the key technologies to make the explosive welding of LF6 aluminum alloy and 1Cr18Ni9Ti stainless steel tubes feasible. Numerical simulation shows that radial contraction and slope collision through continuous local plastic deformation are necessary for the good bonding of tubes. Stand-off distances between tubes （D1 and D2） and explosives amount （R） have effect on the plastic deformation, moving velocity, and bonding of tubes. D1 of 1 mm, D2 of 2 mm, and R of 2/3 are suitable for the explosive welding of LF6-L2-1Cr18Ni9Ti three-layer tubes. The plastic strain and moving velocity of the flyer tubes in-crease with the increase of stand-off distance. More explosives （R2/3） result in the asymmetrical distribution of plastic strain and non-bonding at the end of detonation on the tubes.

铜/钢爆炸焊接复合界面的显微组织及晶粒结构演化机理

采用光滑粒子仿真、先进表征和理论分析相结合的方法,对铜/钢复合材料爆炸焊接过程中的界面瞬态行为进行深入研究,并详细阐述其显微组织演化机制。根据仿真数据重构波形完整的演化过程,并揭示各种界面特征的形成机制。多尺度EBSD分析表明,界面附近区域呈多样性的晶粒结构,其演化机制主要受塑性流动、动态再结晶和凝固形核三个过程的控制。最后,通过纳米压痕实验建立晶粒结构与力学性能之间的关系。

爆炸焊接铜/钢复合管界面组织表征与性能研究

为了研究应用于压力容器的管道或承压部件的铜/钢双金属复合管材料中晶粒存在形式和力学性能之间的关系,通过爆炸焊技术获得了T2铜/316L不锈钢复合管,并对其界面形貌与微观组织进行分析。结果表明,T2铜/316L不锈钢复合管结合界面处呈现平直界面和周期性波状界面,波形结合区域的平均波长203μm、波高58μm。复合管结合界面两侧的元素发生互扩散,扩散层厚度为1μm。界面处Fe侧晶粒尺寸较小,随着结合界面距离的增加晶粒尺寸逐渐变大。通过纳米压痕试验发现,波峰处界面的纳米压痕结果达到了3.16 GPa,波谷处的纳米压痕结果达到了2.44 GPa,同时波峰处界面附近区域的纳米压痕结果均高于波谷处,Fe侧纳米压痕结果均高于Cu侧。纳米压痕试验获得的力学性能分布规律和微观组织的分布规律相一致。

大壁厚不锈钢复合板压力容器建造关键技术及应用

在大壁厚不锈钢复合板压力容器的建造过程中,通过深入研究其技术要点和难点,优化焊接接头结构设计,成功形成了一套完整的新型建造关键技术。这套技术不仅优化了焊接接头结构,还创新了一系列施工方法,包括筒体加热卷制、接头坡口机加工、接管内壁耐蚀层TIG/FCAW自动堆焊、不锈钢衬管液氮冷套、球形封头内壁耐蚀层带极埋弧堆焊、纵环缝窄间隙埋弧自动焊以及管口接头马鞍型埋弧焊等。这些新型建造关键技术的应用,在提高压力容器质量效果的同时,也带来了显著的经济效益,为行业同类型设备的建造提供借鉴。在未来的研究中,可以进一步探索这些技术在其他领域的应用,以实现更广泛的技术交流和合作。同时,对于大壁厚不锈钢复合板压力容器的建造,仍需不断深入研究其材料特性、工艺参数和施工方法,以不断提高设备的性能和安全性。

Mg/Al真空爆炸焊接微观形貌及力学性能

镁合金和铝合金因具有较高的化学活性,在常规焊接方式下,其表面的氧化物会掺杂到焊接接头内,使得复合板的结合性能下降。为了提高Mg/Al复合板的结合强度,采用真空爆炸焊接法制备了Mg-AZ31B/Al-6061复合板,并与常规空气环境下制备的相同参数复合板进行了对比。通过光学显微镜、扫描电子显微镜、能谱仪以及万能试验机,对结合界面的微观形貌、元素分布和力学性能进行分析。结果表明:由于气体冲击波压力不同,真空环境下复合材料的界面形貌与空气环境下有很大区别;真空环境有效抑制了镁、铝2种金属氧化,在熔化区未检测到金属氧化物。此外,还观察到真空环境下试样的剪切强度和拉伸强度显著增大。因此,真空爆炸焊接对Mg/Al复合板性能的提升起到了重要作用,可以作为一种有效的金属焊接方法。

TA2/AZ31B/2024Al爆炸焊接复合板界面微观结构特征及其动态力学性能

运用平行法爆炸焊接工艺,开展了TA2/AZ31B/2024Al多层轻质金属板材爆炸焊接实验。通过扫描电镜、电子背散射衍射、分离式霍普金森压杆及三维轮廓扫描等测试技术,对多层爆炸焊接复合板界面微观结构特征、材料物相变化规律、复合板材动态力学性能及材料冲击断口特征开展了系统研究。研究结果表明:焊后多层轻质金属复合板的4个焊接界面均呈现出爆炸焊接特有的波形结构特征,结合界面处无明显缺陷,总体焊接质量良好。结合界面处晶粒发生细化并形成细晶区,1060Al过渡层内晶粒组织由于强塑性变形呈现典型的拉长层状晶粒特征,4个结合界面处均出现明显的变形织构与再结晶织构特征。沿X方向的试样最大动态抗压强度达605 MPa,分层断口界面三维形貌呈现近似水面波纹的独特结构特征。沿Z方向的试样最大动态抗压强度达390 MPa,断口界面三维形貌呈现明显的纤维状韧性断裂特征。

基于三圆轨迹规划的MARKⅢ型LNG薄膜舱波纹板机器人焊接

MARKⅢ型LNG薄膜舱波纹板的焊接质量是LNG船建造成功与否的关键之一。为了实现MARKⅢ型LNG薄膜舱1.2mm厚304L不锈钢波纹板的机器人焊接,研究了基于“三圆”连接构思的波纹板机器人焊接的轨迹规划模型,通过模型计算了沿波纹板轨迹焊接过程中的焊枪位置和焊枪姿态坐标,并对模型和计算的结果进行了仿真验证;在此基础上,进行了不锈钢波纹板机器人搭接焊的脉冲等离子弧焊的工艺优化研究。结果表明:本文建立的波纹板机器人焊接的“三圆”轨迹规划模型以及基于该模型计算的焊枪位姿坐标准确;基于模型和计算,结合优化后的脉冲等离子弧焊工艺参数,实现了焊缝成形良好的MARKⅢ型LNG薄膜舱1.2mm厚304L不锈钢波纹板搭接的机器人焊接,焊缝成形达到了法国GTT公司标准文件中提供的成形尺寸标准。

轧制对爆炸焊接TA1/5052与TA1/1060/5052复合板组织与性能的影响

利用爆炸焊接的方法制备纯钛TA1与5052铝合金复合的TA1/5052复合板,以及加入中间层纯铝1060的TA1/1060/5052复合板,研究轧制对爆炸焊接态TA1/5052与TA1/1060/5052复合板组织与性能的影响,以及加入中间层对复合板界面的影响。结果表明:爆炸焊接态的TA1/5052与TA1/1060/5052复合板界面结合良好,在退火后其界面的组织主要为α-Ti、α-Al以及钛铝金属间化合物TiAl3;复合板硬度较钛、铝原始板材有较大的提升,同时具有良好的拉伸与弯曲性能,并且在力学性能测试过程中不发生分层。轧制后,由于轧制下压力的作用,导致复合板扩散层厚度下降,微观组织发生变化,界面附近的晶粒被挤压变形,并在进料过程中被逐渐拉长,呈现出纤维状组织,且轧制过程中产生强烈的加工硬化,导致复合板的抗拉强度与显微硬度增加。加入中间层可以明显改善复合板的界面形貌,抑制界面处Ti/Al金属间化合物的形成。

FCAW焊接修复对AH36/2205不锈钢复合板接头性能的影响

由于减少了贵重合金元素的使用,AH36/2205不锈钢金属复合板在应用中有着巨大的经济效益。复层和基层金属间的物理、化学性质存在差异,焊接质量不稳定,因此焊接修复不可避免。为了研究焊接修复对于焊接接头性能的影响,针对14 mm+2 mm的AH36/2205不锈钢金属复合板,采用药芯焊丝气体保护焊(FCAW)进行1~3次焊接修复模拟试验。结果表明:AH36/2205不锈钢金属复合板不适合采用FCAW进行焊接修复,1次修复试板的点蚀率达到了167.7 mdd。随着修复次数的增加,不锈钢复合板接头的力学性能及耐晶间腐蚀性能良好,而点蚀率增加,接头的耐点蚀性能下降。

SUS441不锈钢/Al金属间化合物微叠层复合板的界面结构与力学性能

采用“表面预处理—交替层叠—热轧复合—热处理”的工艺流程制备了SUS441不锈钢/Al金属间化合物微叠层复合板。利用光学显微镜、X射线衍射仪、扫描电子显微镜等检测与表征方法研究了热处理温度对复合板界面形貌、微观组织、物相组成、维氏硬度、拉伸性能的影响。结果表明:复合板界面结合良好;热处理后,固–液反应界面氧化严重,易导致界面分层而开裂;固–固、固–半固、固–液热处理后,金属间化合物层由均匀层和两相层组成,均匀层的物相组成为Fe_(2)A_(15),两相层的物相组成为Fe_(4)Al_(13)和Al_(13)Cr_(2),且两相层具有韧性特征,固–半固反应所得到的复合板的综合力学性能最佳。