对集装箱自攻螺钉在 180kW无马弗网带炉机组上进行碳氮共渗后 ,出现渗层表面硬度分散的现象 ,进行金相分析 ,发现在离表面 40 μm的范围内存在着点状黑色组织 ,导致渗层表面硬度偏低。检验证明点状黑色组织属孔洞。通过工艺试验找到可有效防止黑色组织产生的措施 ,使碳氮共渗表面硬度趋向集中并服从正态规律分布 ,使产品的质量更加稳定。 After the surface of the container self-tapping screw was carbonitridiZed on a 180 kW non-muffle belt furnace unit, the surface hardness distribution of the coating appeared. Metallographic analysis showed that there was a dot black in the range of 40 μm from the surface Tissue, resulting in infiltrated surface hardness is low. Inspection proved that the point of black tissue is a hole. Through the process of test to find the measures to effectively prevent the black tissue from occurring, so that the surface hardness of carbonitriding tend to focus and follow the normal distribution of the law, so that the quality of the product more stable.