气气换热器壳侧膨胀节开裂原因分析

Analyzing the Causes of Cracking on Expansion Joints at the Shell Side of the Gas-Gas Heat Exchanger

针对气气换热器壳侧膨胀节发生开裂的问题,通过对设备的结构、工作参数及膨胀节的制造情况等相关数据进行收集和分析,再结合对开裂膨胀节取样进行的一系列实验室检测检验,最终判断膨胀节开裂原因为其长期工作在有湿硫化氢介质的环境下,存在湿硫化氢应力腐蚀,而奥氏体不锈钢膨胀节在冷加工成型过程中,由于加工硬化产生了大量的形变马氏体,进一步减弱了钢材耐应力腐蚀的能力,最终造成膨胀节开裂。根据开裂原因有针对性地提出了预防和改进措施。

To solve cracking on expansion joints at the shell side of the gas-gas heat exchangers,the article introduces how relevant data such as equipment structure,operating parameters and manufacturing of the expansion joints were collected and analyzed.Compounded with results of a series of laboratory tests on samplings from the cracked expansion joint,a final conclusion was drawn that the cracking was caused by two factors.First was stress corrosion by wet hydrogen sulfide which long exists in its operation circumstance.Second was a large amount of deformation martensite generated during the cold processing molding process of the austenitic stainless steel expansion joint,further weakening the steel’s resistance to stress corrosion and creating cracks on the joint.Preventive and improvement measures were put forward in respect to the identified cracking causes.