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为促进低合金高强钢厚板激光焊接技术的发展,本文利用光纤激光-电弧复合焊接方法焊接25mm厚的27Si Mn低合金高强钢,分析了焊接接头的微观组织和硬度、拉伸、冲击等力学性能。结果表明,接头钝边焊道焊缝(WM)和热影响区(HAZ)组织主要以马氏体为主,填充焊道的焊缝主要由晶内针状铁素体、沿晶界分布的少量先共析铁素体和上贝氏体组成,热影响区以马氏体组织为主。焊接接头硬度分布不均匀,钝边焊道的硬度最高值出现在焊缝;而填充焊道的硬度最高值出现在粗晶区,母材最低。接头拉伸试验均断于母材。冲击试验显示的各区域冲击韧性的排序为:填充焊道WM>填充焊道HAZ>钝边焊道HAZ>钝边焊道WM>母材,钝边焊道焊缝冲击断口既存在脆性断裂区也存在韧性断裂区,填充焊道焊缝的冲击断口仅观察到韧性断裂区。
In order to promote the development of laser welding technology of low alloy and high strength steel plate, the mechanical and electrical properties of 27SiMn low alloy high strength steel (25mm thick) were welded by fiber laser-arc hybrid welding method. The microstructure and hardness, tensile and impact mechanics performance. The results show that the welded joints of the passivated weld (WM) and the heat affected zone (HAZ) are mainly composed of martensite, and the weld of filled weld is mainly composed of intragranular acicular ferrite and distributed along the grain boundaries A small amount of pro-eutectoid ferrite and bainite composition, heat-affected zone to martensite-based. The hardness distribution of welded joints is not uniform, and the highest hardness of the passivated bead appears in the weld seam. The highest hardness of the filler bead appears in the coarse grain region with the lowest base metal. Tensile test joints were broken in the base metal. Impact toughness shows the order of impact toughness for each zone: filler bead WM> filler bead HAZ> blunt edge weld HAZ> blunt edge weld WM> base material, blunt edge weld Weld impact fracture both have brittle fracture zones There are also ductile fracture zones where only the ductile fracture zone is observed at the impact fracture of the weld bead weld.