板壳式换热器裂纹缺陷的安全评定

The Safety Evaluation of Crackles on Casing-Structure Heat Exchanger

通过对低合金钢焊接板壳式换热器壳体与接管焊接区裂纹宏观和微观观测，进行了常规力学计算，根据国标ＣＶＤＡ－１９８４－１４及国际焊接学会规范ＩＷＸ－７４９－７４进行的断裂力学计算分析，确定了换热器焊缝区裂纹产生的机理及容许裂纹尺寸，提出了只要能继续严格执行焊后热处理规范，对焊后出现的微裂纹，就不会影响设备的强度和使用。为该品牌的换热器的继续开发、生产正常服役，提供了可靠的理论依据。

Through the macroscopic and microcosmic observation on crackles in the body and on casing-structure heat exchanger which made from low alloy steel in welded area of connection pipes. The routine mechanic calculation analysis is made. According to the calculation based on the standards of international CVDA-1984-14 and international welding institute IIWX-749-74, production mechanism of crackle in the welding area and the allowable size of crackles are determined. The authors conclude that the welding minicrackles can′t affect the strength and the usage of the structure if heat treatment standards can be strictly followed, this provides a sound theoretical basis for continual developing and usage of this kind of heat exchanger.