控压氮化工艺对42CrMo钢渗后组织和性能的影响  

Effect of Controlled Pressure Nitriding Process on the Microstructure and Properties of 42CrMo Steel

作　　者：李瑞鑫 吴重仲 王一民 刘大勇 闫文吉 丁彦超 曲明贵[3] 吕知清 LI Ruixin;WU Chongzhong;WANG Yimin;LIU Dayong;YAN Wenji;DING Yanchao;QU Minggui;LYU Zhiqing(Key Laboratory of Advanced Forging and Stamping Technology and Science of Ministry of Education,School of Mechanical Engineering,Yanshan University,Hebei Qinhuangdao 066004,China;Fujian Wind Power Generation Co.,Ltd.,China General Nuclear Power,Fuzhou 350000,China;State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Hebei Qinhuangdao 066004,China)

机构地区：[1]燕山大学机械工程学院先进锻压成形技术与科学教育部重点实验室,河北秦皇岛066004 [2]中广核福建风力发电有限公司,福州350000 [3]燕山大学亚稳材料技术与科学国家重点实验室,河北秦皇岛066004

出　　处：《表面技术》2025年第7期180-188,202,共10页Surface Technology

基　　金：国家自然科学基金(52171050);上海大件热制造工程技术研究中心资助项目(18DZ2253400);河北省创新能力提升计划(22567609H)。

摘　　要：目的在较短时间和较低温度下,制备力学性能稳定的均匀氮化层。方法以合金结构钢42CrMo为研究对象,通过调控气体氮化工艺中的温度和保温时间,同时引入压力参数,研究42CrMo钢的表层力学性能和微观组织的演变。对控压氮化后试样的渗氮层表面硬度、厚度、化合物组成及N元素的分布进行分析和测试。结果在温度510℃、压力0.3 MPa、时间5 h的条件下,采用控压氮化工艺可以达到较优的渗氮效果,硬度最高可达790HV,化合物层分布均匀,N的浓度显示,扩散区的深度超过180μm。渗氮层受到压力的影响较大,增压状态可以加速氮化过程,并使渗氮层分布更均匀。在温度较低时,增加保温时间可以提高氮化硬度和梯度,在温度较高时则不明显。在短时间氮化时提高温度有助于改善氮化效果,长时间则不明显,提高温度和时间对N浓度的扩散均有较大影响。渗氮层表面存在N浓度较高的由N原子和Fe原子化合形成的Fe_(2-3)N、Fe4N等化合物。经氮化后,工件表面N原子的质量分数最高可达10%以上,随着渗层深度的增加,氮化物含量逐渐降低。结论与传统气体氮化工艺相比,采用控压氮化工艺在提升氮化效率的同时使得氮化层组织结构分布更加均匀,较大幅度地提升了其综合力学性能。For the purpose of preparing a uniformly nitrided layer with stable mechanical properties on the surface of 42CrMo alloy structural steel within a relatively short time at a relatively low temperature,the temperature and holding time parameters of the gas nitriding process were regulated.Meanwhile,the pressure parameter was introduced to investigate the evolution of the mechanical properties and microstructure of the surface layer of 42CrMo alloy structural steel after nitriding.The surface hardness,nitrided layer thickness,compound composition,and distribution of N element of the samples after controlled-pressure nitriding were analyzed and tested.By observing the hardness and microstructure morphology,it was found that the microstructure of the nitrided sample consisted of a white bright layer on the surface,and N diffusion zone,and a matrix.The nitrided layer was significantly affected by pressure.Compared with the normal pressure state,the pressurized state could accelerate the nitriding process,making the nitrided layer thicken faster and distribute more uniformly.However,when the pressure increased from 0.3 MPa to 0.5 MPa,the improvement effect on nitriding was not pronounced.In contrast to a higher temperature,increasing the holding time at a lower temperature could more effectively improve the hardness and gradient distribution of the nitrided surface layer.Similarly,in the short-term nitriding process,the improvement in the nitriding effect by increasing the temperature was more significant compared with that in the long term.The increase in temperature and time had a significant impact on the diffusion of nitrogen concentration,with the effect of nitriding temperature being more prominent.The nitriding parameters had a relatively small impact on the nitrogen content of the outermost compound layer.When the nitriding temperatures were 480℃and 510℃,the N atom concentration on the surface could reach about 10%(mass)under different nitriding pressures and time.The nitride content gradually decreased wit

关 键 词：气体渗氮 增压渗氮 42CRMO钢 微观组织 表面硬度 氮化层 

分 类 号：TG156.82[金属学及工艺—热处理]