为提高结构件的焊接效率,采用大熔深焊接具有重要的意义.针对隧道结构用厚30 mm的Q355B低合金高强钢,采用大熔深焊接方法进行焊接试验,测试了焊接接头的微观组织与力学性能.结果表明:大熔深焊缝的微观组织主要由大量的铁素体和少量的粒状贝氏体组成;大熔深焊接接头的熔深显著增加,极大地提高了焊接效率;大熔深焊缝的显微硬度与母材接近,整个接头为等强匹配;随着焊接电流的增加,焊缝的显微硬度、抗拉强度变化不大,冲击韧性有所下降;大熔深焊接最佳的电流范围为320～360 A.
Research on Large Deep Penetration Welding of Low-alloy High-strength Steel
In order to improve the welding efficiency of structure members,it is of great significance to adopt large penetration welding.The welding test of Q355B low-alloy high-strength steel for tunnel structure with a thickness of 30 mm was carried out by using the method of deep penetration welding,and the microstructure and mechanical properties of the welded joint were tested.The results show that the microstructure of deep penetration weld is mainly composed of a large number of ferrite and a small number of granular bainite;the penetration depth of large penetration welded joints is significantly increased,which greatly improves the welding efficiency;the microhardness of the weld with large penetration is close to that of the base metal,and the whole joint is an equal strength matching;with the increase of welding current,the microhardness and tensile strength of the weld have little change,and the impact toughness decreases;the best current range for deep penetration welding is 320 A-360 A.
large deep penetration weldinglow-alloy high-strength steelmechanical property test
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