预加热振动焊接方法在乙烯裂解炉PQE裂纹修复中的应用

Application of preheating vibration welding in PQE crack repair of ethylene cracking furnace

某公司乙烯裂解炉第一急冷换热器(PQE)在大修时进行了着色探伤检测,检测发现:急冷换热器入口带叉锥体与下连接件多处焊缝熔合线存在裂纹,其中部分为贯穿性裂纹。为解决补焊后焊缝熔合线及母材依然出现裂纹的问题,采用一种红外预热装置对焊接件进行预热且在焊接过程中对构件注入振动外场的焊接工艺。预加热振动焊接方法的应用,减少了焊件焊接残余应力,提高了焊接部位的力学性能、焊缝的抗疲劳性和断裂韧性,焊件裂纹修复效果良好,保证了焊接质量。

Dye detection was conducted for the first rapid cooling heat exchanger(PQE) of ethylene cracking furnace in a company during overhaul. It was found that there are cracks on weld-fusion line between fork cone at inlet of heat exchanger and lower connector, some of which are penetrating cracks. To avoid recurrence of similar incidents after repair welding, an infrared preheating device was adopted to preheat welding parts, and vibration welding process was applied into components during welding. The application of preheating vibration welding reduces welding residual stress of weldment and improves mechanical properties of welding material, fatigue resistance and fracture toughness of weld. It is proved to be effective for weldment crack repair.