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研究了不同焊接工艺对SS400钢X形坡口焊后不同区域显微组织与显微硬度的影响。结果表明,当采用酸性焊条热输入小于20 kJ/cm进行焊接时,熔合区大量铁素体、下贝氏体与母材原奥氏体相互交织,母材与焊缝金属连接性较好,但焊缝针状铁素体粗化且过热区出现大量上贝氏体。采用碱性焊条热输入为30 kJ/cm焊接时,焊缝内形成均匀细小的铁素体和无碳粒状贝氏体组织,焊后性能相对较好。此外,X形坡口第2道焊的焊接热作用对首道焊的高硬度组织有明显改善。
The effects of different welding processes on microstructure and microhardness of X-shaped groove in SS400 steel after welding were studied. The results show that a large amount of ferrite and lower bainite in the fusion zone are intertwined with the original austenite of the parent material when the heat input of acidic welding rod is less than 20 kJ / cm. The base metal has good connectivity with the weld metal, But the weld acicular ferrite coarsening and superheated zone appeared a large number of upper bainite. When welding with alkaline welding rod with heat input of 30 kJ / cm, uniform and fine ferrite and carbon-free granular bainite are formed in the weld, and the performance after welding is relatively good. In addition, the welding heat effect of the second weld of X-shaped groove has a significant improvement on the high hardness of the first weld.