超低碳不锈钢管-管板的焊接工艺试验与应用

超低碳不锈钢316L管-管板的焊接采用手工钨极氩弧焊,对316L不锈钢的焊接性进行了分析和研究,通过工艺试验,证明了焊接工艺的可靠性,并在不锈钢浓H2SO4冷却器阳极保护(管壳式)设备的焊接中取得了满意的效果.     

316L超低碳不锈钢的焊接性分析

用不同焊接方式和同一焊接方式不同焊口坡度焊接多种316L超低碳不锈钢焊接试板。通过外观观察、X射线检验、机械性能检验等方法对成品进行分析,掌握了316L材料的焊接性能。结果表明通过采取适当的工艺措施,316L奥氏体不锈钢焊接接头可以避免热裂纹、晶间腐蚀、刀状腐蚀等缺陷。同时验证了316L焊接接头良好的耐蚀性和机械性能。     

2507双相不锈钢在尿素设备中的应用分析

从材料化学成分、力学物理性能及耐蚀性能等方面对2507双相不锈钢和316L(尿素级不锈钢)进行了对比分析,探讨了2507双相不锈钢应用于尿素合成设备的可行性;另外,针对2507双相不锈钢的成形性能、焊接性能及热处理性能,提出几点工程应用方面的要求,为2507双相不锈钢的进一步推广应用提供一些技术参考.     

316L不锈钢焊接质量控制

论述了316L管道焊接方法、焊接参数、常见缺陷及预防措施等。通过焊前准备、施工、验收3个阶段的质量控制,达到了保证316L不锈钢管道焊接质量、防止泄露的效果。     

16MnR＋316L复合钢板焊接工艺及性能研究

介绍了16MnR＋316L不锈钢复合钢板进行几种不同焊接工艺的焊接试验,并对其焊缝力学性能及化学性能进行对比,通过试验确定16MnR＋316L复合钢板的最佳焊接工艺。     

环氧氯丙烷生产设备的腐蚀失效分析与材料选择

文章分析了环氧氯丙烷(ECH)生产中反应器和换热器(材料为304不锈钢)的腐蚀失效原因,并通过SEM进行了表面腐蚀形貌的表征。分析表明混合物中H+、Cl-的溶解作用和应力腐蚀开裂(SCC)是造成设备腐蚀穿孔失效的主要原因。建议降低混合液中Cl-含量及提高溶液pH;选用更加耐蚀的材料如:钛及钛合金,316 L不锈钢及化学镀Ni-P镀层。     

电刷镀镍过程中316L不锈钢表面状态的变化

利用X射线光电子能谱仪(XPS)、扫描电镜(SEM)、能谱仪(EDS)等设备研究了电刷镀镍各步骤对316L不锈钢表面状态的影响。清洗可有效地降低316L不锈钢表面的C含量;活化会对表面造成腐蚀,提高表面粗糙度;预镀镍可以获得仅有较少微裂纹的薄镀层。虽然刷镀镍层表面存在较多微裂纹,但仍可以满足钎焊对厚度、结合力和耐高温性能的要求。     

油田集输管线电化学腐蚀及防护研究

油田集输管线电化学腐蚀问题严重影响管线系统的使用寿命,为解决这一问题,对油田集输管线电化学腐蚀现象迚行了评价。采用油田集输管线中常应用的316L不锈钢作为实验对象,利用不同质量浓度的氯离子对316L不锈钢腐蚀,通过扫描电镜和能谱分析得到质量浓度为10 g·L~(-1)与50 g·L~(-1)氯离子侵蚀下的316L不锈钢微观形貌,具体分析得知,10g·L~(-1)氯离子对316L不锈钢侵蚀较轻,然而随着氯离子浓度的增加,氯离子对316L不锈钢侵蚀随之增加,在氯离子质量浓度为50 g·L~(-1)时,316L不锈钢腐蚀现象严重。在此基础上,根据油田集输管线电化学腐蚀情冴提出了相应的防护措施。     

导电聚苯胺膜的合成及其防腐性能

为了增强不锈钢(SS)双极板的耐腐蚀性能,采用循环伏安法(CV)在316L不锈钢(SS)表面电合成聚苯胺(PANI)薄膜。以0.2 M H_2SO_4+x NaCl水溶液为腐蚀介质,通过测量开路电位(OCP)、Tafel极化曲线和电化学阻抗谱(EIS),研究Cl-浓度对PANI/316L SS复合体系腐蚀行为的影响。结果显示:随着CV循环次数的增加PANI薄膜逐渐变厚;Cl~-浓度对PANI/316L SS耐腐蚀性能影响显著,随Cl~-浓度的增大,PANI/316L SS体系的耐蚀性降低。     

316LMod高压管道焊接工艺和质量控制全面融合研究

316LMod是一种低碳不锈钢材料,具有很强的抗晶间腐蚀能力,在尿素工业中应用十分普遍,文章就该材料的性能优势进行简单的介绍,重点分析316LMod高压管道的焊接工艺及焊接质量控制方法。     

奥氏体不锈钢输油管道焊缝的应力腐蚀失效分析

某渣油管道的材质为奥氏体不锈钢,在设备检修时发现其接头上共有两处产生焊缝开裂失效.利用检测设备对管道焊缝的化学成分及腐蚀物、金相组织、断口、机械性能测试、无损检测分析、焊接问题等项目进行分析,结果表明:应力腐蚀是管道失效的原因,而较差的焊接质量使接头形成了应力源和腐蚀源.     

Pitting and stress corrosion cracking behavior in welded austenitic stainless steel

The effect of microstructural changes in 304 austenitic stainless steel induced by the processes of gas tungsten arc welding (GTAW) and laser-beam welding (LBW) on the pitting and stress corrosion cracking (SCC) behaviors was investigated. According to the in situ observations with scanning reference electrode technique (SRET) and the breakdown potentials of the test material with various microstructures, the GTAW process made the weld metal (WM) and heat-affected zone (HAZ) more sensitive to pitting corrosion than base metal (BM), but the LBW process improved the pitting resistance of the WM. In the initiation stage of SCC, the cracks in the BM and HAZ propagated in a transgranular mode. Then, the crack growth mechanism changed gradually into a mixed transgranular + intergranular mode. The cracks in the WM were likely to propagate along the dendritic boundaries. The crack initiation rate, crack initiation lifetime and crack propagation rate indicated that the high-to-low order of SCC resistance is almost the same as that for pitting resistance. High heat-input (and low cooling rate) was likely to induce the segregation of alloying elements and formation of Cr-depleted zones, resulting in the degradation in the corrosion resistance.     

Effect of stress on the passivation of Si-DLC coating as stent materials in simulated body environment

DLC coating can be used for vascular stents to prevent the stainless steel substrate from eluting Ni and Cr by plastic deformation and corrosion environment. The stress corrosion cracking (SCC) of Si-diamond-like carbon (Si-DLC) coated on 316L stainless steel was studied in a simulated body environment of a deaerated 0.89 wt.% NaCl electrolyte at 37 °C. This paper investigated the effect of Si-DLC coating on the SCC of 316L SS by slow-strain-rate test (SSRT), constant load test (CLT), and electrochemical impedance spectroscopy (EIS). The EIS data were monitored for the elastic and plastic regions under CLT to determine the electrochemical behavior of the passive film during SCC phenomena. The Si-DLC coated steel exhibited more ductility than uncoated steel and less susceptibility to SCC in this environment. According to X-ray photoelectron spectroscopy (XPS) analysis, the film repassivation occurs due to the presence of the silicon oxide layer on the Si-DLC film surface.     

35CrMo和00Cr13Ni5Mo硫化氢环境应力腐蚀开裂

用慢应变速率拉伸实验和U形试样浸泡实验、电化学极化技术并结合微观分析手段,在湿硫化氢介质中研究了35CrMo和00Cr13Ni5Mo两种钢的应力腐蚀开裂行为规律。结果表明,35CrMo和00Cr13Ni5Mo钢在实验条件下均具有一定应力腐蚀开裂（SCC）敏感性,其敏感性随着溶液pH的降低和H₂ S浓度的增大而增大;00Cr13Ni5Mo 在实验条件下抗SCC的能力均高于同条件下的35CrMo,在pH3.0的溶液中,二者性能比较接近,在pH4.5的溶液中,00Cr13Ni5Mo 耐H₂S环境SCC的性能明显提高,高于35CrMo,这主要是因为00Cr13Ni5Mo中的耐蚀合金元素增强了其钝化膜的稳定性、降低了氢脆作用所致。     

不锈钢复合板焊接缺陷的返修

本文从不锈钢复合板的焊接性分析了焊接接头缺陷形成的原因,以及结合经验对焊接缺陷返修定位和返修工艺进行了介绍,提出了采用合理的坡口形式,是保证不锈钢复合板焊接质量,避免返修难的有效途径。     

U形管换热器开裂原因分析

借助光学和扫描电子显微镜,从材料成分、微观组织和性能角度,分析了Ｕ 形管换热器开裂原因。这是一种典型的应力腐蚀开裂,裂纹从管内壁开始向外壁扩展。３２１不锈钢在此工作条件下的耐蚀性好于３０４ 不锈钢。建议采用Ｃｒ Ｍｏ 钢,并从工艺上控制Ｃｌ－ 和Ｓ２－ 的数量。     

Optimization of weld bonding process parameters of austenitic stainless steel 304L and low carbon steel sheet dissimilar joints

Weld bonding is a hybrid joining process used to produce weld joints between similar or dissimilar metallic materials. In this work, a systematic study has been undertaken to investigate the effect of the input process parameters on the weld joint quality of dissimilar materials i.e. austenitic stainless steel 304L and low carbon steel sheet, in terms of joint strength. Experiments were planned on the basis of response surface methodology technique with three control factor and their three levels of process parameters. Experimental results were used to develop a mathematical model to predict the tensile shear strength and peel strength of the weld joint. A mathematical model, correlating the process parameters and their interaction on responses, was also established. The developed model was validated with the confirmation test case experiment, and it has been observed that the developed model is capable to evaluate weld joint strength within the range of process parameters being used. Numerical optimization technique was applied to find out the optimal set of input parameters.     

奥氏体不锈钢在Cl~-介质中应力腐蚀研究

评述了奥氏体不锈钢在氯化物介质中应力腐蚀开裂。从环境、冶金和力学等方面论述了ＳＣＣ的主要因素,综合论述了控制奥氏体不锈钢ＳＣＣ的工程参量和安全评定的方法。提出了预防奥氏体不锈钢应力腐蚀的一些措施。     

苯酚管道焊缝晶间腐蚀原因研究

针对某化工厂苯酚装置中粗苯酚管道的三通、弯头焊缝处的腐蚀问题进行了分析和研究。通过对材质试件进行宏观检查、金相组织分析以及试件材质化学成分分析和介质成分分析等方法对腐蚀的原因进行了分析研究。研究结果表明：粗苯酚管道焊缝腐蚀失效为典型的奥氏体不锈钢晶间腐蚀。造成不锈钢晶间腐蚀的原因包括：材质与设计不符;焊缝处存在组织不均匀、晶粒粗大等缺陷;介质具有腐蚀性等。提出了粗苯酚不锈钢管道焊缝接头的防腐蚀措施。     

304不锈钢应力腐蚀的临界氯离子浓度

通过慢拉伸实验得出了304不锈钢应力腐蚀敏感性与溶液中Cl-浓度的关系,用扫描电镜对拉伸试样的断口形貌进行了分析,得出了304不锈钢发生应力腐蚀的临界氯离子浓度。采用自行设计的装置对304不锈钢试样施加拉应力,通过恒应变条件下的电化学原位测试研究了304不锈钢钝化膜破裂电位与氯离子浓度的关系。得出导致钝化膜破裂电位突变的Cl-浓度与发生应力腐蚀破裂的临界Cl-浓度是基本一致的结论。