再生器发生应力腐蚀开裂的探讨

针对炼油厂催化装置再生器下部件壁发生开裂的现象，通过分析催化装置近几年原料油田的变化、烟气露点测试结果与现场器壁温度对比，认为这是一种氢应力腐蚀开裂（SCC）。结合氢应力腐蚀特点制定了修复方案，特别是焊前预热、焊后热处理，选择合适的焊条及板材，降低了焊道和热影响区硬度，消除残余应力。并对再生器下部壁采取保温措施，确保再生器下部外壁温高于露点（137℃），使之无法在下部器壁形成水汽冷凝液，有效防止SCC的发生。     

液氨球罐应力腐蚀开裂的诊断

一台由日本工业标准JIS-SPV36钢制造、直径21.5m、容积5200m~3的大型液氨球罐,由于应力腐蚀开裂,其安全性受到严重威胁.本研究针对该球罐裂纹特征和腐蚀产物进行分析,并估算结构的可靠度;在大量现场实测和试件试验数据统计分析的基础上,提出了防止产生应力腐蚀裂纹的诊断方法,并已于1986年12月该球罐年度大修时实施.     

如何防止或避免压力容器的应力腐蚀开裂

随着我国压力容器的大型化和高温高压化,压力容器的安全事故越来越多,而应力腐蚀断裂是一个主要的原因,已占到事故总数的42%,是一种危害性很大的灾害性腐蚀。本文从应力腐蚀开裂的概念入手,分析了应力腐蚀的特点,并在设计、制造及使用等几个重点环节提出了具体的应对措施,具有积极的意义。     

压力容器在设计制造过程中如何防止或避免应力腐蚀开裂

通过对应力腐蚀的特点及影响因素、裂纹形态的分析,提出避免应力腐蚀开裂的防控措施,为压力容器设计人员和制造单位提供参考。     

压力容器的应力腐蚀开裂及其安全技术措施

简要介绍了应力腐蚀开裂的分析方法、引起压力容器应力腐蚀开裂的主要因素及防止措施。     

奥氏体不锈钢换热管应力腐蚀开裂分析

为了调查奥氏体不锈钢换热管泄漏的原因,对不锈钢换热管中裂纹宏观形貌、金相组织、管材化学成分和腐蚀产物成分、换热管的力学性能以及换热管服役环境进行了综合分析。分析结果表明:换热管开裂原因为高温蒸汽中氯离子引起的奥氏体不锈钢应力腐蚀,并提出了相应的预防措施。     

奥氏体不锈钢炉体应力腐蚀破裂失效分析

316L不锈钢是一种耐蚀性能很好的材料，但是安装质量特别是焊接质量对其应力腐蚀破裂(SCC)性能有很大的影响，针对抚顺石化多次沿焊接热影响区(HAZ)发生断裂事故的一套316L不锈钢设备进行失效分析，认为该设备的断裂属于SCC，焊接接头质量差是造成断裂的根本原因。     

不锈钢设备的连多硫酸应力腐蚀开裂机理与防护

探讨了不锈钢设备连多硫酸应力腐蚀开裂的机理,对连多硫酸的形成,及其对不锈钢设备应力腐蚀的过程,以及影响不锈钢设备的连多硫酸应力腐蚀开裂的因素进行了分析,并提出了若干种预防连多硫酸应力腐蚀开裂的措施。     

碳钢空冷器硫化过程预防应力腐蚀开裂措施

催化剂预硫化是多数加氢装置必经的过程,由于硫化过程使系统中硫化氢的浓度会达到上万ppm,碳钢空冷器发生湿硫化氢环境应力腐蚀开裂的概率大大提高。本文就近期两个新开工炼厂为例,一个发生湿硫化氢环境下应力腐蚀开裂事故,一个安全渡过硫化阶段,从不同硫化过程到碳钢空冷器制造过程进行对比阐述。分析如何避免碳钢材质空冷器发生湿硫化氢环境下应力腐蚀开裂问题。     

浅析压力容器应力腐蚀及其控制措施

分析了压力容器应力腐蚀的危害性以及影响因素,阐述了压力容器应力腐蚀的形态特征,综述了近年来学者们对压力容器应力腐蚀的研究进展,提出了控制压力容器应力腐蚀的措施。     

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.     

转筒干燥机裂纹失效分析

就复肥厂常规直接加热转筒干燥机焊缝上的裂纹进行了宏观及微观分析 ,找出裂纹形成的原因为应力腐蚀开裂 ,并提出修补措施     

Cover cracking of reinforced concrete due to rebar corrosion induced by chloride penetration

Cracking of concrete cover due to corrosion induced expansion of steel rebar is one of the major causes of the deterioration of reinforced concrete (RC) structures exposed to marine environments and de-icing salts.This paper presents two models that deal with the chloride-induced corrosion and subsequent cracking of concrete cover in RC structures. The former analyses the chloride diffusion within partially saturated concrete. A comprehensive model is developed through the governing equations of moisture, heat and chloride-ion flow. Nonlinearity of diffusion coefficients, chloride binding isotherms and convection phenomena are also highlighted. The latter describes the internal cracking around the bar due to expansive pressures as corrosion of the reinforcing bar progresses. Once a certain chloride concentration threshold is reached in the area surrounding the bar, oxidation of steel begins and oxide products are generated, which occupy much greater volume than the original steel consumed by corrosion. An embedded cohesive crack model is applied for cracking simulation.Both models are incorporated in the same finite element program. The models are chained, though not explicitly coupled, at first instance. Comparisons with experimental results are carried out, with reasonably good agreements being obtained. The work is a step forward for the integration of the two traditional phases (initiation and propagation) widely used in the literature and usually analysed separately. The estimation of the service life of the structure needs to evaluate the associated time for each one.     

裂解炉炉管开裂原因分析

对发生失效破裂的炉管进行了宏观形貌分析、断口形貌分析、金相分析、有限元应力分析等 ,得出导致炉管破裂的主要原因是炉管在制造过程中产生缺陷引起的应力集中和特定的腐蚀环境共同作用下产生应力腐蚀断裂。     

蒸汽加热器弯头对焊焊缝开裂失效分析

利用光学显微镜、扫描电镜、电子能谱仪等测试手段,从材料成分、微观组织、断口形貌以及腐蚀产物成分等角度,分析了蒸汽加热器弯头对焊焊缝开裂失效的原因——系统操作过程中碱液进入蒸汽加热器所引起的应力腐蚀所致,同时提出了避免蒸汽加热器弯头对焊焊缝开裂失效的防护措施。     

乙烯裂解炉对流段原料预热翅片管开裂原因分析及对策

分析了造成乙烯装置裂解炉翅片管开裂的原因 ,并在实际生产、维修和设计中采取了相应的对策 ,消除了再次发生类似问题的可能性     

Thermal-induced blister cracking behavior of annealed sandwich-structured TiN/CrAlN films

Sandwich-structured TiN/CrAlN films were rationally designed using metallic Ti and Al-Cr alloy targets by RF-pulsed magnetron sputtering. After obtained films were annealed at diverse temperatures at atmospheric pressure for 1 h, the hardness reveals an apparent decrease evolution from 29.2 to 15.7 GPa and H/E* ratio declines below 0.1 with increasing annealing temperature. Meanwhile, the grain size gradually becomes larger from 16.3 to 130.0 nm with increasing annealing temperature. Interestingly, it is observed that cracking behavior of sandwich-structured composite TiN/CrAlN films at elevated temperature is originated from the top of the blisters where main component is alumina on the surface, in virtue of intrinsically induced stress during oxidation, thermal expansion mismatch and phase transformation of the oxide layer. No cracks, nevertheless, are yielded in the film between any two blisters. Herein, these findings provide some beneficial references for preparing high quality films and coatings in high temperature service.