【摘要】 某炼油厂加氢装置高压换热器管层出口管线所安装的不锈钢耐震压力表内部弹簧管发生开裂,通过宏观观察、电镜观察、能谱分析、金相分析、氢含量分析、硬度测试、综合分析等手段,对失效样件进行了检测和分析,结果表明压力表弹簧管的开裂主要是由于工作温度较高,加上Ni和Mo含量不达标,材料奥氏体不锈钢内部含有过饱和的氢,由于氢分子不能及时逸出,在弹簧管扁圆顶部应力集中的部位,在湿硫化氢的环境下,发生的一种氢损伤,即硫化物应力腐蚀开裂。通过控制引进压力表的材质、对压力表的弹簧管需进行定氢检测、控制介质中的水含量、适度降低工作温度等措施可抑制开裂。更多还原

【Abstract】 The spring tube installed in the stainless steel pressure gauge on the outlet line of HP heat exchanger in the hydrogenation plant of a refinery cracked.The macro observation,SEM and EDX examinations,energy spectrometry analysis,metallographic analysis,hydrogen content analysis and hardness test of failed samples show that the cracking of spring tube in the pressure gauge is mainly caused by high service temperature.In addition,as the Ni and Mo contents are out of specifications and austenitic stainless steel has higher content of super-saturated hydrogen,these hydrogen molecules can not be released and are concentrated in the stress-concentrated area in the top of oblate tube.The result shows that the cracking mechanism is sulfide stress corrosion cracking.Therefore,the hydrogen damage(i.e.SSCC) occurs in the wet hydrogen sulfide environment.The cracking can be controlled by selection of right material for pressure gauge,hydrogen examination of spring tube,control of water in service media and proper reduction of operating temperature,etc.更多还原