不锈钢/镍基合金异质不等厚板激光焊焊接工艺

Laser welding process of stainless steel/nickel-based alloy heterogeneous plates with different thickness

  • 摘要:
    目的 不锈钢与镍基合金的不等厚板的复合结构在航空、航天和电力行业具有广泛的应用前景,开展不锈钢与镍基合金激光焊焊接工艺的研究具有重要意义。
    方法 采用激光焊焊接技术来连接304不锈钢和Inconel 718镍基合金。试验对比分析了焊接速度和光束偏移量等参数对焊接接头焊缝成形、微观组织和抗拉强度的影响规律。
    结果 结果表明,焊接功率3 kW、激光焦点偏向不锈钢侧0.2 mm时,随着焊接速度的增加,焊缝的曲率半径会随着焊接速度的增加呈现出先增加后减少的趋势。其中,焊接速度为1.5~2.0 m/min时的焊缝成形性最好。激光光束聚焦在不锈钢侧时的整体成形性要优于激光光束聚焦在镍基合金侧的成形。
    结论 激光作用位置偏置镍基合金侧时,焊接接头的抗拉强度普遍较高,获得的最大抗拉强度为647 MPa。最后观察断裂位置时发现,断口多数断镍基合金一侧,断裂模式以微孔聚集型的塑性断裂为主。不锈钢侧焊缝组织中有明显的非对流混合区,而镍基合金侧未观察到非对流混合区。

     

    Abstract: Objective The hybrid structure of stainless steel/nickel-based alloy with different thickness has wide application prospects in the aviation, aerospace, and power industries. It is of great significance to carry out study on laser welding process of stainless steel and nickel-based alloys. Methods 304 stainless steel and Inconel 718 nickel-based alloy materials are connected by laser welding technology. Influence of welding speed and beam offset on weld formation, microstructure and tensile strength of welded joints is compared and analyzed. Results The results show that when welding power is 3 kW and laser focus shifts to stainless steel by 0.2 mm, curvature radius increases first and then decreases as welding speed increases. Among them, weld formability is the best when welding speed is 1.5~2.0 m/min. The overall formability when laser beam is focused on the stainless steel side is better than that on the nickel-based alloy side. Conclusion When laser position is offset on the nickel-based alloy side, tensile strength of welded joints is generally higher, the maximum tensile strength is 647 MPa. Finally, through observing location of fracture, it is found that most of fractures are on the nickel-based alloy side, and fractures are dominated by micro-hole aggregation type plastic fractures. Non-convective mixing zone is observed in microstructure of weld on the stainless steel side, but not on the nickel-based alloy side.

     

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