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目前,高频电阻焊法生产的电焊钢管已开始用于寒冷地带。但在极低温条件下使用时,钢管焊缝部位的韧性恶化比管体部分严重,主要原因是焊缝部位存在氧化物夹杂。虽选择适当的焊接条件可排除大部分氯化物夹杂,但往往在焊缝接合面上仍残留有10～20μm左右的细小氧化物,使焊缝部位韧性下降。过去,为了防止焊缝部位产生氧化物,常采用N_2惰性气体保护焊。但这种焊接方法往往不能完全排除焊缝部位的有害氧化物,对改善焊缝韧性效果有限。
Currently, the production of high-frequency resistance welding electric steel pipe has begun to be used in cold areas. However, the use of extremely low temperature conditions, the toughness of pipe joints worse than the pipe part of the serious, mainly due to oxide inclusions in the weld site. Although the choice of appropriate welding conditions can rule out the majority of chloride inclusions, but often there is still left in the weld joint surface of about 10 ~ 20μm fine oxides, the toughness of the weld area decreased. In the past, in order to prevent the oxide weld site, often using inert gas N_2 welding. However, this welding method often can not completely eliminate the harmful oxide parts of the weld, to improve the toughness of the weld effect is limited.