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.

Microstructure and corrosion resistance of 304 stainless steel electroslag strip cladding

The 304 stainless steel strips were deposited one layer on carbon steel base metal by electroslag strip cladding （ESC） and submerged arc cladding （SAC）, respectively. The solidification microstrueture of ESC metal was analyzed by the optical microscopy, scanning electron microscope and energy dispersive spectroscopy. The corrosion resistance studies of strip cladding metals were carried out in 10% oxalic acid electrolytic etching test. The results showed that the cladding metal obtained by ESC presented low content of C, high content of Cr and enough alloying element of Ni in the chemical composition. The transition zone of ESC with small width was almost parallel with the base metal, leading to a lower dilution. There are three types of solidification modes （ A→AF→FA ） occurred in the ESC metal due to the decrease of cooling rate and degree of dilution from the transition zone to the top of ESC metal. As a result, the microstructure of ESC metal exhibited mainly austenite with a small amount of ferrite, contributing to achievement of better corrosion resistance.

Microstructure Evolution and Cracking Control of 316L Stainless Steel Manufactured by Multi-layer Laser Cladding

Multi-layer laser cladding manufacturing is a newly developed rapid manufacturing technology. It is a powerful tool for direct fabrication of three-dimensional fully dense metal components and part repairing. In this paper, the microstructure evolution and properties of 316L stainless steel deposited with this technology was investigated, compact components with properties similar to the as-cast and wrought annealed material was obtained. Cracking was eliminated by introducing of supersonic vibration and application of parameter adjustment technologies.

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.

Influence of Clad Metal Chemistry on Stress Corrosion Cracking Behaviour of Stainless Steels Claddings in Chloride Solution

The effect of clad metal composition on stress corrosion cracking (SCC) behavior of three types of SMAW filler metals (E308L-16, E309-16 and E316L-16), used for cladding components subjected to highly corrosive conditions, was investigated in boiling 43% MgCl2 solution. In order to evaluate the stress corrosion cracking susceptibility of the top layer, constant load tests and metallographic examinations in tested SCC specimens were conducted. The susceptibility to stress corrosion cracking was evaluated in terms of the time-to-fracture. Results showed that the E309-16 clad metal presented the best SCC resistance. This may be attributed to the presence of a discontinuous delta-ferrite network in the austenitic matrix, which acted as a barrier to cracks propagation. Concerning to E308-16 and E316L-16 clad metals, results showed that these presented a similar SCC test performance. Their higher SCC susceptibility may be attributed to the presence of continuous vermicular delta-ferrite in their microstructure.

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.

EFFECT OF LASER CLADDING ON HYDROGEN EMBRITTLEMENT RESISTANCE OF AUSTENITIC STAINLESS STEEL

A plasma spraying plus laser remelting technique has been performed. onaustenite stainless steel (22Cr-13Ni-5Mn ) with a newly developed hydrogen resistantcoating material. The results show that the surface cladding layer can effectively reducethe hydrogen content increasing of the stainless steel under the atmosphere of high pres-sure (30MPa), high temperature (300℃) and high purity (99. 995%) hydrogen andgreatly improve the hydrogen embrittlement resistance of the stain1ess steel. Throughanalysis of microstructure, a mechanism of hydrogen embrittlement resistance is presentedthat at room temperature, the surface oxidation films, both existing on the surface ofcoated and uncoated specimens, inhibit the adsorption and diffusion of hydrogen molecu-lae. However, at high temperature, it is the surface cladding layer with relatively low sol-ubility and Permeability for hydrogen that significantly reduces the amount of hydrogenentering into the interior of the material and improves its hydrogen embrittfement resis-tance.

Revisiting Stainless Steel as PWR Fuel Rod Cladding after Fukushima Daiichi Accident

In the past, stainless steel was utilized as cladding in many PWRs （pressurized water reactors）, and its performance under irradiation was excellent. However, stainless steel was replaced by zirconium-based alloy as cladding material mainly due to its lower neutron absorption cross section. Now, stainless steel cladding appears as a possible solution for safety problems related to hydrogen production and explosion as occurred in Fukushima Daiichi accident. The aim of this paper is to discuss the steady-state irradiation performance using stainless steel as cladding. The results show that stainless steel rods display higher fuel temperatures and wider pellet-cladding gaps than Zircaloy rods and no gap closure. The thermal performance of the two rods is very similar and the neutron absorption penalty due to stainless steel use could be compensating by combining small increase in U-235 enrichment and pitch size changes.

Effect of process parameters on microstructural and mechanical properties of Ti.SS 304L explosive cladding

The present work pertains to the study of microstructure and mechanical properties of explosively cladded commercially pure titanium(cpTi) with austenitic stainless steel(SS 304L) subjected to varied process parameters, viz., loading ratios(mass of explosive or mass of flyer plate) and preset angles. The microstructural study reveals the transformation from straight to wavy interface while increasing loading ratios. Vickers hardness increases with loading ratios, and the maximum hardness is witnessed in the closer proximity of collision interface. Ram tensile and shear strength of explosive claddings are higher than that of parent plates. While the base plate fails in impact test, the flyer plate is deformed, indicating good impact strength. Increased mass of claddings, due to oxide formation, is witnessed in corrosion tests, which confirms the superiority of explosive claddings in corrosive environment. Triaxial weldability window, an analytical estimation for Ti-SS 304L explosive claddings, is developed and correlated.

316L不锈钢掺杂SiC环状同轴送粉TIG熔覆层组织结构与性能

TIG熔覆是经济高效的表面修复方法,与传统的预置粉末法相比,同轴送粉法具有优良的适应性,但是试验研究相对较少.自主设计制造了环状同轴送粉TIG熔覆焊枪,与管状同轴送粉TIG熔覆焊枪相比,制造的熔覆层不存在熄弧位置凹坑、焊缝不够平直以及焊缝熔宽不一致等问题,而且具有更高的熔覆效率.结果表明,采用优化的焊接热输入、送粉量和SiC含量参数匹配,在316L不锈钢表面进行环状同轴送粉TIG熔覆,获得了外观优良的单层单道熔覆层、单层多道熔覆层.对熔覆层进行显微硬度测量、微观组织及元素成分分析、宏观电化学腐蚀试验、微区电化学腐蚀试验以及耐磨性能测试,并与母材进行了比对,环状同轴送粉TIG熔覆导入的SiC粉末有效地提升了熔覆层的耐蚀性与耐磨性.

“双碳”战略背景下不锈钢复合钢板结构减碳前景分析

为探究不锈钢复合钢板结构的减碳前景,本文分析了“双碳”战略背景下钢结构行业的发展趋势,包括智能建造快速发展、新兴产业提供广阔市场以及高性能钢材和高性能结构发展更为迅猛,指出不锈钢复合钢板结构可兼顾高性能、经济性以及减碳要求。基于全寿命周期评价理论,采用排放因子法,提出了不锈钢复合钢板结构的碳排放计算方法。结果表明:不锈钢复合钢板结构的全寿命周期碳排放量比钢结构少36%,比不锈钢结构少10%。用不锈钢复合钢板结构替代普通钢结构,可以有效减少碳排放;替代不锈钢结构可以在减碳的同时具有良好的经济性。

激光熔覆Stellite 6合金涂层的耐磨耐蚀性能研究

为提高阀杆用SUS630不锈钢的耐磨耐蚀性能,利用激光熔覆技术在其表面制备Stellite 6钴基合金涂层,随后对比研究了Stellite 6合金涂层和SUS630不锈钢基体的显微硬度、摩擦磨损性能和腐蚀性能。结果表明:相对于SUS630不锈钢,Stellite 6合金涂层的硬度提高了25%,磨损体积减少了50%,说明Stellite 6合金涂层的耐磨性能优于SUS630不锈钢基体;此外,在3.5%NaCl溶液中,Stellite 6合金涂层的腐蚀电位(-0.18 V)和钝化膜的阻抗值(367 kΩcm^(2))均高于SUS630不锈钢基体的腐蚀电位(-0.35 V)和钝化膜的阻抗值(129 kΩcm^(2)),而其钝化电流密度(10^(-7)-10^(-6)A/cm^(2))小于SUS630不锈钢基体的钝化电流密度(10^(-6)-10^(-5)A/cm^(2)),说明Stellite 6合金涂层的耐腐蚀性能优于SUS630不锈钢基体。因此,激光熔覆Stellite 6合金涂层可提高SUS630不锈钢的耐磨耐蚀性能。

不锈钢复合钢H形截面钢梁受剪承载性能

基于复合钢本构模型,明确了复合比β对不锈钢复合钢应力-应变性能的影响。通过试验结果的承载曲线和破坏模式验证了数值模拟方法的准确性,进而以β、腹板宽高比a/hw和腹板高厚比hw/tw为变量开展300个数值模型的参数分析,系统分析了各变量对不锈钢复合钢H形截面钢梁受剪承载曲线和极限承载力的影响。研究结果表明:随着β的增加,不锈钢复合钢应力-应变曲线中的屈服平台逐渐消失,复合钢应力-应变性能逐渐由碳钢转变为不锈钢。当β较小时,不锈钢复合钢应力-应变曲线存在明显的屈服平台,这削弱了复合钢的应变强化对H形截面钢梁受剪承载性能的有利影响。随着β的增加,不锈钢复合钢的非线性应变强化性能逐渐增强,导致H形截面钢梁的延性性能逐渐提高,强度性能逐渐降低。经过验证,既有的欧洲规范设计公式对不锈钢复合钢H形截面钢梁受剪极限承载力的预测过于保守。基于参数分析结果,建立了考虑β影响的腹板贡献系数计算方法。研究结论有助于推广不锈钢复合钢的工程应用。

低碳钢及其不锈钢复合钢材低周疲劳行为的对比研究

不锈钢复合钢材在土木工程结构中得到了越来越多的关注和应用,但是其在循环荷载作用下的力学行为还缺乏足够的认识。通过单轴拉伸试验和不同应变幅条件下的对称应变控制加载低周疲劳试验,对比研究了2 mm+10 mm热轧304+Q235B不锈钢复合钢材及其基层Q235B碳钢钢材的循环弹-塑性特性和低周疲劳寿命;结合数值模拟得到的疲劳试件截面应力分布,分析了复合钢材低周疲劳失效模式的力学机理。结果表明,在拉伸和循环荷载下,复层304不锈钢与基层Q235B碳钢之间均没有出现界面剥离现象;复合钢材及Q235B碳钢均表现出与加载应变幅正相关的循环硬化行为,且前者的循环应力响应大于后者;复合钢材的低周疲劳初始裂纹均出现在Q235B碳钢侧,这是由于复层不锈钢和基层碳钢不同的拉应力状态和塑性变形能力共同造成的,但是复合钢材与Q235B碳钢的低周疲劳寿命未表现出明显的区别。该批次304+Q235B不锈钢复合钢材具有良好的低周疲劳性能,可代替Q235B碳钢用于对腐蚀防护性能具有较高要求的工程构件中。

不锈钢复合钢材焊接方管T形管节点试验研究

不锈钢复合钢材是一种成本低、强度高、耐腐蚀性能优异的高性能钢材,其在对耐腐蚀要求高的工程结构应用中尤其具有竞争力。该文旨在通过试验,研究不锈钢复合钢材焊接方管T形节点在静力和低周往复荷载作用下的力学性能,设计、制作了4个管节点试件并完成了加载,基于试验结果重点研究了各管节点试件的试验过程、破坏模式、荷载-位移响应和应变发展等;按中国规范GB 50017和欧洲规范EN 1993-1-8进行了节点承载力计算,并与试验值进行了对比。研究结果表明,对于支管承受轴向压力的管节点试件,以主管上表面塑性破坏为主;对于支管承受水平低周往复荷载的管节点试件,以主管上表面塑性变形和主管与支管之间连接焊缝断裂破坏为主;当管节点破坏模式符合现行规范GB 50017和EN 1993-1-8中规定时,相关承载力计算公式仍适用于此类不锈钢复合钢材焊接方管T形管节点的设计计算。

热处理工艺对激光熔覆316L温度场与应力场的影响规律

为研究不同热处理工艺对激光熔覆残余应力的调控作用,利用ANSYS有限元分析软件建立了热力耦合模型,对不同温度(22~900℃)的熔覆前预热处理、不同温度(200~1000℃)的熔覆后退火处理以及熔覆前后协同热处理条件下的激光熔覆316L不锈钢温度场和应力场进行了数值模拟。研究结果表明:预热对熔池温度影响最大,熔池温度随预热温度的增高而增高;退火处理对激光熔覆残余应力的改善效果最好,800℃退火处理可使残余应力减小约50%,其次是熔覆前后协同热处理,可使残余应力减小约35%,预热处理对激光熔覆残余应力有一定改善,其中预热500℃可使残余应力减小约20%。

等离子熔覆硼化物覆层的耐蚀性

采用等离子熔覆技术将自制的Mo-Fe-B-Cr药芯焊丝熔覆在316L不锈钢表面制备了硼化物覆层,通过扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)和显微硬度计对硼化物覆层的组织、成分、物相和显微硬度进行分析,并通过电化学试验和中性盐雾试验对覆层的耐蚀性进行研究。结果表明:硼化物覆层主要由MO_(2)FeB_(2)、(Mo,Fe,Cr)3B_(2)、α-Fe和Fe_(23)(C,B)6组成,其显微硬度约为不锈钢基体的3.9倍;在中性环境中硼化物覆层的耐蚀性略低于316L不锈钢,而在酸性环境中硼化物覆层的耐蚀性要优于316L不锈钢;在中性盐雾腐蚀过程中,硼化物覆层表面会生成致密性良好的钝化膜,从而使覆层具备良好的耐蚀性。因此,硼化物覆层在拥有高硬度的同时还兼具良好的耐蚀性。

基于316L过渡层的431不锈钢激光熔覆层组织与性能研究

采用激光熔覆技术制备316L不锈钢涂层作为过渡层,在过渡层表面激光熔覆431马氏体不锈钢作为表面熔覆层.通过OM和SEM观察分析了熔覆层截面的微观组织特征,并借助XRD分析了熔覆层和过渡层的物相组成,利用显微硬度仪和电化学工作站测试熔覆层的硬度分布和耐腐蚀性.试验结果表明:加入过渡层后获得的熔覆层表面光滑平整,没有气孔裂纹等缺陷;表面熔覆层由马氏体、铁素体和少量残余奥氏体组成,过渡层由奥氏体组成;整个熔覆层的硬度从顶端向下呈现出梯度减小,表面熔覆层的硬度为538 HV,比基材提高了3倍,过渡层的平均硬度为300 HV;熔覆层的腐蚀电流为0.9569×10^(-6) A/cm^(2),腐蚀电位为-0.16644 V,熔覆层的耐腐蚀性优于基材.

20Cr13不锈钢表面激光熔覆M2涂层性能分析

采用激光熔覆技术在20Cr13基体表面制备M2涂层,利用超景深显微镜、光学显微镜、XRD以及维氏硬度仪对M2涂层的宏观形貌、微观组织、物相组成和显微硬度进行分析,利用电化学工作站测量M2涂层和20Cr13基体的Tafel曲线以及腐蚀形式。研究结果表明:涂层的主相是α-Fe和碳化物硬质相(M_(23)C_(6)和M_(7)C_(3)),与基体形成良好冶金结合。涂层的硬度均值在729.5 HV,是基体硬度均值的3.8倍。基体的自腐蚀电位最大,自腐蚀电流密度最小,涂层的耐腐蚀性比基体的差;涂层的腐蚀形式以点蚀和晶间腐蚀为主,基体以孔蚀和晶间腐蚀为主。

Ni/c-BN对激光熔覆316L不锈钢熔覆层组织与耐蚀性的影响

采用激光熔覆技术在马氏体不锈钢(ZG06Cr13Ni4Mo)表面制备了Ni/c-BN增强316L不锈钢复合熔覆层。通过XRD、SEM、EDS、电化学试验和冲蚀试验分析了不同Ni/c-BN含量对熔覆层的显微组织和和耐蚀性影响。结果表明,复合熔覆层的物相由FeCr_(0.29)Ni_(0.16)C_(0.06)固溶体组成,随着Ni/c-BN添加量的增加,其顶部组织的等轴晶数量减少,胞状树枝晶的数量增多。复合熔覆层的耐蚀性随Ni/c-BN添加量的增加呈先升高后降低的趋势,当Ni/c-BN添加量为5wt.%时,熔覆层的耐蚀性最好。过量的Ni/c-BN使得熔覆层表面存在气孔,且导致熔覆层内部存在少量大尺寸残留c-BN,降低了熔覆层的耐腐蚀性和耐冲蚀性。