硫黄回收单元不锈钢三通阀裂纹修复处理

Repair process for cracks of stainless steel three-way valve in sulfur recovery unit

某天然气净化厂硫黄回收单元不锈钢三通程序切换阀发生泄漏,影响装置正常运行。为修复该三通阀,从材质、焊接、结构、使用介质等方面对故障进行了分析。判断为焊接时晶间区域形成"贫铬区",从而引起的晶间腐蚀。针对该情况制定了小线能量焊接、焊后固溶处理的方式进行修复。最终成功修复三通阀裂纹,保证了装置正常运行。该修复工艺的成功运用为因贫铬引起晶间腐蚀的奥氏体不锈钢裂纹的修复提供了有效方法。

A stainless steel three-way programmable switching valve in the sulfur recovery unit of a natural gas purification plant developed a leak,affecting the normal operation uptime of the facilities.In order to develop valve repair procedure,factors such as material,welding,structure,and process medium were analyzed.It is concluded that the"chromium-depleted zone"is formed in the inter-granular area during welding,resulting in inter-granular corrosion.To tackle this problem,small heat input welding and post-weld solution treatment methods were developed for repair.Finally,the crack of the three-way valve was successfully repaired to allow the normal operation of the device.The successful application of the repair process provides an effective method for the repair of cracks in austenitic stainless steel caused by chromium depletion.