我厂在采用自动焊焊接锅炉时,发现20K钢板的冷弯角较差(未退火),一般弯到85～90°时在热影响区出现裂纹(要求冷弯角α>100°)。由于这一缺陷的产生,使我们自动焊迅速用于生产受到了阻碍。我厂没有大型退火炉,若要建造一台,一方面时间来不及,另一方面投资也很大,为了不影响生产, When we adopt the automatic welding and welding boiler, we found that the cold bending angle of 20K steel plate is not good (not annealed), and cracks occur in the heat-affected zone when it is bent to 85 ~ 90 ° (the required cold bending angle α> 100 °). As a result of this flaw, our rapid application of automated welding to production was hampered. I plant no large annealing furnace, to build a unit, on the one hand time was too late, on the other hand the investment is also great, in order not to affect the production,