液压支架用Q690高强钢焊接接头的强韧性匹配

Strengthen and Toughen Matching on Welded Joint of Q690 High Strength Steel Used in Hydraulic Support

为满足液压支架用Q690高强钢的使用要求,采用不同强度级别的焊丝对Q690高强钢进行焊接,研究了焊接接头的强韧性匹配问题。结果表明:采用GHS75H焊丝焊接时,焊缝组织主要为板条贝氏体,具有较高的强度,焊接接头断于母材Q690,且冲击韧性与Q690相近,塑性良好;采用MK·GHS70-G焊丝焊接时,焊缝组织主要为针状铁素体和板条贝氏体,强度较低,焊接接头断于焊缝,但焊接接头冲击韧性明显高于Q690,塑性良好。两种焊丝与Q690的强韧性匹配均较好,但GHS75H更符合液压支架向轻量化和高可靠性发展的要求。

In order to achieve the requirements of Q690 high strength steel which can be used for hydraulic support, two weld solid wires with different strength are adopted to weld Q690 steel. The strengthen and toughen matching of the welded joint were studied. The results show that the lath bainite is the primary microstructure of weld metal with high strength when adopting GHS75G solid wire welding, and the fracture position is located in Q690. The welded joint has good plastic and similar impact toughness with Q690. The acicular ferrite and lath bainite is the primary microstructure of weld metal with low strength when adopting MK. GHS70-G solid wire welding, and the fracture position is located in weld seam. However, the toughness of the welded joint is higher than Q690, and then then welded joint has good plastic. Although two solid wires have good matching with Q690 high strength steel. The properties of GHS75H accords with the lightweight and high reliability requirements of hydraulic support.