预氧化对不同离子渗氮工艺的影响  

Effect of pre-oxidation on different ion nitriding processes

作　　者：李双喜 顾敏 孙启峰 Li Shuangxi;Gu Min;Sun Qifeng(Zhengzhou Research Institute of Mechanical Engineering,Zhengzhou Henan 450001,China)

机构地区：[1]郑州机械研究所有限公司,河南郑州450001

出　　处：《金属热处理》2019年第1期61-64,共4页Heat Treatment of Metals

摘　　要：利用光学显微镜、显微硬度计、XRD、SEM等分析了预氧化对40CrNiMo钢离子渗氮过程的影响。结果发现:在300℃氧化1 h的40CrNiMo试样,表面生成了厚0. 4～0. 7μm、以Fe_3O_4和Fe_2O_3为主的氧化层。在随后的540℃离子渗氮过程中,当渗氮时间较短(4 h)时,试样出现渗层浅、分布不均和硬度低等缺陷;但随着渗氮时间的延长(8 h),预氧化表现出了一定的催渗效果,同时渗层中脉状氮化物减少;当渗氮时间延长至16 h时,预氧化的催渗效果更加显著,但渗层的疏松有所增加。Effect of pre-oxidation on ion nitriding process of 40 CrNiMo steel was analyzed by means of metallographic microscope,microhardness meter,XRD and SEM. The results show that after pre-oxidation at 300 ℃ for 1 h,an oxide layer with a thickness of 0. 4-0. 7 μm and mainly contains Fe3O4 and Fe2O3 is formed on the surface of the 40 CrNiMo steel. In the subsequent processs of ion nitriding at540 ℃,when the nitriding time is shorter( 4 h),the nitriding layer shows defects such as shallow infiltration,uneven distribution and low hardness. However,as the nitriding time is prolonged to 8 h,the pre-oxidation shows a certain helpful effect on nitriding,while the vein nitride in the layer decreased. Moreover,when the nitriding time is extended to 16 h,the infiltration boosting effect of pre-oxidation is more significant,but the porosity of the layer increased.

关 键 词：离子渗氮 预氧化 催渗 

分 类 号：TG156.8[金属学及工艺—热处理]