一、前言20g是工业锅炉生产中大量使用的材料,近年来,由于自动埋弧焊后接头的冷弯开裂,严重影响着产品的质量和生产周期。许多单位根据本厂生产中的实际情况和问题曾进行了大量试验研究工作,并提出了各自的看法。有的单位认为造成自动埋弧焊接头冷弯开裂的原因是由于碳和硫、磷含量较高导致了液化裂纹的产生有的认为是由于20g中夹杂物含量较高或有夹层存在所致;有的研究认为冷弯开裂与氢的作用有关;还有的单位则认为导致20g埋弧焊接头开裂的原因是由于冷弯时采用两倍板厚的冷 I. Introduction 20g is a large-scale use of industrial boiler production of materials, in recent years, due to automatic submerged arc welded joints after the cold cracking, seriously affecting the quality of the product and the production cycle. Many units according to the actual situation in the factory production and problems have conducted a large number of experimental research and put forward their own views. Some units think that the reason for the auto-submerged arc welded joint cold-cracking is due to the high content of carbon, sulfur and phosphorus, which led to the generation of liquefaction cracks. Some believe that the content of inclusions in 20g is high or the interlayer exists; Some studies suggest that cold cracking is related to the action of hydrogen. Others think that the reason for the cracking of a 20-gauge submerged arc welded joint is that the cold