Journal article
Gradient Microstructure in a Gear Steel Produced by Pressurized Gas Nitriding
Chongqing University1
Department of Mechanical Engineering, Technical University of Denmark2
Manufacturing Engineering, Department of Mechanical Engineering, Technical University of Denmark3
Yanshan University4
Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark5
A tempered martensitic gear steel (18CrNiMo7-6) sample was nitrided on two sides using a 5 atm pressurized gas at 530 °C for five hours. The nitrided sample was characterized by means of microhardness, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. A microhardness gradient was identified over a distance of 1000 µm with hardness values from 900 HV0.1 at the surface to 300 HV0.1 in the center matrix.
The gradient microstructure was mainly divided into three zones: (i) a nitride compound layer at the top surface (~20 µm thick), (ii) a diffusion zone with containing precipitates (~350 µm thick), and (iii) the center matrix of the tempered martensite. Compared with carburized sample, the harder surface of the nitrided one ensures a better performance of the present pressured gas nitrided gears.
Language: | English |
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Publisher: | MDPI |
Year: | 2019 |
Pages: | 3797 |
ISSN: | 19961944 |
Types: | Journal article |
DOI: | 10.3390/ma12223797 |
ORCIDs: | 0000-0002-2723-7724 , Zhang, Xiaodan and Huang, Xiaoxu |
Descriptive and experimental mechanics Electrical engineering. Electronics. Nuclear engineering Engineering (General). Civil engineering (General) Microscopy QC120-168.85 QH201-278.5 T TA1-2040 TK1-9971 Technology gear steel gradient microstructure microhardness pressurized gas nitriding