Abstract A method of laser remelting with an ultra-thin additional element coating on the surface was put forward to improve both the hardenability of mild steel and the hardening efficiency. Both the 100 % C and the 50 % C-50 % Cr (in mass) coatings were used. The additional surface coating increased the fusion efficiency of the laser irradiation because the carbon particles on the surface had a higher laser absorption rate than the mild steel. With the introduction of both surface coatings, the hardness of the melted zone was significantly improved, and the maximum hardness reached the hardness of the high carbon steel. The molten flows drove the diffusion of the elements, which contributed to the increase of hardness in the melted zone. This manuscript provides a potential method for improving the hardness of the surface layer by introducing new elements (C, Cr) in laser remelting, especially for the material with low hardenability.

中文翻译：

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利用超薄附加元素涂层在激光重熔中通过熔融金属流增强硬度

摘要 为提高低碳钢的淬透性和淬透效率，提出了一种表面超薄附加元素涂层的激光重熔方法。使用了 100% C 和 50% C-50% Cr（质量）涂层。额外的表面涂层提高了激光照射的融合效率，因为表面上的碳颗粒比低碳钢具有更高的激光吸收率。随着两种表面涂层的引入，熔化区的硬度显着提高，最大硬度达到了高碳钢的硬度。熔融流动推动了元素的扩散，这有助于提高熔化区的硬度。