NM450/ZG30SiMn构件双丝窄间隙GMAW焊缝成形及组织与性能

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中图分类号： TG444+.4

Abstract： Narrow gap welding of 50mm thick NM450 and ZG30SiMn dissimilar steels was carried out with double wire GMAW. Angle of welding wire and welding mode were explored in simulated narrow gap groove. It was found that when angle of welding wire was 6∘ and welding mode of two welders was constant pressure，wellformed welded joints without macroscopic defects could be obtained.In thick plate welding，two arcs could burn stably on sidewall，and melt could flow sufficiently and wet sidewallto make weld appear concave.Due to presence of angle between two wires，incomplete fusion of sidewall was effectively suppressed，and no macroscopic cracks appeared under the condition of no preheating.Microstructure of weld mainly consisted of alarge amount of acicular ferriteand a small amount of massive ferrite.There was more massive ferrite in covering layer，and massive ferrite was relatively large，while number of massive ferite in backing layer and filling layer was small， and massive ferrite was relatively small. Consequently，microhardness of backing layer was greater than that of filling layer and microhardness of filling layer was greater than that of covering layer.

Key words： narrow gap ; double wire; incomplete fusion of sidewall; ferrite； microhardness

0前言

刮板运输机是用于煤矿运输的重要设备，中部槽是刮板运输机的主要部件，而且也是使用量与消耗量最大的部件[1]。（剩余7548字）