T250无钴马氏体时效钢薄壁件焊接工艺试验

Welding experiments on thin-wall part of T250 cobalt free maraging steel

为了确保T250无钴马氏体时效钢薄壁筒形压力容器的焊接质量和可靠性,制备薄壁片状、筒形焊接试件及角焊缝焊接试件进行了钨极氩弧焊焊接工艺试验。试验结果表明,T250钢具有良好的焊接性,薄壁件钨极氩弧焊不易出现冷裂纹,焊前不需预热,焊后不需进行消除应力的热处理;焊接时,应严格控制焊接电流,防止出现焊接缺陷;焊接后,焊接接头的强度不高,需要通过时效或固溶+时效处理才能达到超高强度钢的强度,其时效工序不可忽视。

For ensuring the welding workmanship and reliability of thin-wall cylindrical pressure vessel of T250 cobalt free maraging steel,GTAW welding experiments were carried out with a thin-wall cylindrical sample and a corner weld sample.The results indicated that T250 steel has good weldability,cold cracking in GTAW joint of the thin-wall part little occurs,and neither pre-heat before welding nor heat treatment for removing stress after welding are required.In welding process,the welding current should be controlled strictly to prevent the weld defects.Besides,the strength of welded joint is not high after welding,so it is necessary to improve the joint strength to reach the similar strength of ultrastrength steel by ageing or quench annealing + aging treatment.