摘要
目的探究38CrMoAl钢钛催渗等离子渗氮工艺及机理。方法在其他工艺参数确定的情况下,通过常规等离子渗氮与钛催渗等离子渗氮处理对比试验,研究38CrMoAl钢钛催渗离子渗氮处理随渗氮时间的变化规律。对试样进行表面硬度、渗层深度检测和显微金相组织与SEM形貌的观察,探究不同处理工艺的催渗效果及钛催渗等离子渗氮的机理。结果在渗氮的前3 h,渗氮层厚度增加明显,当渗氮时间超过3 h后,其氮化层的厚度便趋于饱和。对比不同时间(3、5、8h)钛催渗等离子渗氮的表面硬度,差距不大。综合得出38CrMoAl钢在渗氮温度535℃、氨气流量2.0 L/min的工艺参数下,钛催渗等离子渗氮效率最优的渗氮时间为3h,其表面硬度为1160.8HV,渗层深度为300μm,优于常规离子渗氮8h的作用效果。结论38CrMoAl钢试样经过钛催渗等离子渗氮后,渗层的表面硬度和深度明显高于常规离子渗氮。钛的加入可以促使合金元素向表面富集,有利于表面合金化,提升渗氮效率,增强渗氮效果。
This paper aims to explore the mechanism of plasma nitriding process for 38 CrMoAl steel.Under the condition that other process parameters are determined,through the contrast test of conventional plasma nitriding and titanium catalyzed plasma nitriding,the variation law of titanium catalyzed plasma nitriding treatment with nitriding time of 38 CrMoAl steel is studied.The surface hardness,depth,micro-structure and SEM morphology of the samples are observed to explore the effect of different treatment processes and the nitriding mechanism of plasma nitriding.It is shown that in the first 3 hours of nitriding,the thickness of nitriding layer increases obviously.When the nitriding time exceeds 3 hours,the thickness of nitriding layer tends to be saturated.At the same time,comparing with the surface hardness of titanium-catalyzed nitriding at different times,there is little difference in surface hardness in 3,5 and 8 hours.It is concluded that the optimal nitriding time is 3 hours under the conditions of nitriding temperature 535 ℃ and ammonia flow rate 2.0 L/min.Under this process parameter,the surface hardness of titanium ion nitriding is 1160.8 HV,and the penetration depth is 300 μm,which is better than the effect of conventional ion nitriding for 8 hours.The surface hardness and depth of the nitrided layer of 38 CrMoAl steel sample after plasma nitriding with titanium catalyst are significantly higher than that of conventional plasma nitriding.The addition of titanium can promote the enrichment of alloying elements to the surface,which is conducive to surface alloying,nitriding efficiency improvement,and nitriding effect enhancement.
作者
钟厉
王帅峰
门昕皓
韩西
ZHONG Li;WANG Shuai-feng;MEN Xin-hao;HAN Xi(School of Mechatronics and Vehicle Engineering,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2021年第12期159-166,共8页
Surface Technology
基金
重庆市自然科学基金面上项目(cstc2020jcyj-msxmX0749)
重庆市研究生联合培养基地项目(JDLHPYJD2020031)
重庆市研究生导师团队建设项目(JDDSTD2019007)。
