摘要
对乙二醇装置零效蒸发器内壁开裂状况、性质和原因加以探讨。结果表明,裂纹基本属于弱氧化性介质条件下的晶间腐蚀开裂;介质中含有一定量的乙酸(CH3COOH)和少量甲酸(HCOOH),塔体材料抗晶间腐蚀性能不足,不适当的焊接工艺导致部分热影响区较长时间处于敏化温度(450-850℃)范围是引发塔体开裂的主要因素。防治途径包括:采用超低碳C≤0.02%、含有一定量Mo(2%~4%)或一定量艿铁素体(3%~10%)的奥氏体不锈钢制作壳体;严格执行小热输入、小摆动、窄焊道、低层间温度的焊接工艺;严格控制介质中杂质含量及pH值。
Situation,character and reason of innerwall cracks of zero - order evaporator were studied . The results showed that above cracks are intergranular corrosion cracking basically in weak oxidative medium; they are caused by following factors mainly: contain some acetic acid and little formic acid in active medium, IGCC - resistance of shell material is imuiticient, improper welding technology lead to local HAZ in the sensitized temperature range(450 ~ 850 ℃ )for longer time. Prevention measures include : select austenitic stainless steel with carbon content ≤ 0.02 Wt %, molybdenum content 2 ~4 Wt % or δ errite content 3 ~10 structure % ; use small heat input, little swing, narrow bead and low interpass temperature during welding process; control strictly impurity content and pH value of medium.
出处
《压力容器》
北大核心
2007年第4期45-50,共6页
Pressure Vessel Technology
关键词
乙二醇装置零效蒸发器
晶间腐蚀开裂
控制和处理措施
zero-order evaporator of ethanediol plant
intergranular corrosion cracking
control measures