低碳钢的激光热处理研究

Investigation on Laser Heat Treating of Low carbon Steel

低碳钢由于含碳量低，难以通过常规热处理方法达到理想的硬化效果。我们根据激光热处理的特点，对低碳钢进行了硬化处理。本文通过对含Ｃ量０．２％的钢样进行激光热处理实验，得到了显微硬度ＨＶ５００左右，深度０．５ｍｍ的硬化层。金相分析表明，相变区为板条马氏体组织。研究分析表明，晶粒细化、高的马氏体含量、马氏体高位错密度和固溶含碳量是获得超高硬度的主要原因。

Low carbon steel is difficult to be hardened by normal method of heat treatment because of its low content of carbon.According to the character of laser heat treatment,we try to harden low carbon steel by laser heat treatment.In this paper we can obtain the hardened layer of microhardness HV500 and depth 0.5mm after laser heat treating of low carbon steel containing 0.2% C.Metallographic test results show that the microstructure of hardened layer is lathy martensite.We assume that the ultrahigh hardness is mainly due to the ultrafine grains,high density dislocation and more content of carbon in martensite.