The material characteristics of high toughness and high strength in steel are usually not available at the same time. However, it would be an advantage if high-strength steels would show high impact toughness also at lower temperatures for applications in critical surroundings. In this paper, an approach of multi-layer welding of high-strength steel is presented in order to increase the weld-metal toughness using wire material in combination with thermal cycle modifications. Promising interlocking microstructures were found after multiple tempering of the previously applied structure at homogeneously distributed material in the weld seam. It was found that short thermal cycles during laser processing lead to insufficient time for carbon diffusion, which leads to remaining ferrite structures in contrast to the prediction of welding transformation diagrams. The additionally applied heating cycles during multi-layer laser welding induce the formation of interlocking microstructures that help to increase the weld seam toughness.

钢中高韧性和高强度的材料特性通常无法同时获得。但是，如果高强度钢在较低温度下也能显示出高冲击韧性，则可用于关键环境。在本文中，提出了一种多层焊接高强度钢的方法，目的是通过结合线材材料和热循环改进来提高焊缝金属的韧性。在焊缝中均匀分布的材料上对先前应用的结构进行多次回火后，发现了有希望的互锁微结构。发现在激光加工过程中短的热循环导致碳扩散时间不足，与焊接变换图的预测相反，这会导致残留铁素体结构。在多层激光焊接过程中额外施加的加热循环会导致形成互锁的微结构，从而有助于增加焊缝的韧性。