Affiliation:
1. China Petroleum Pipeline Scientific Institute
2. China Petroleum Pipeline Bureau
3. Henan Petroleum Engineering Construction Co., Ltd.
Abstract
Have studied microstructure of the gas nitriding layer and the laser quenching/ nitriding layer using the X-ray diffractometer and the transmission electron microscope to the brittl of nitriding layer. The results show that the content of Fe3N in composite nitrided layer increased from 14.74% to the 69.45%, while the crisp hard ξ-Fe2N content dropped from 79.95%to 25.03%, Especially the Cr2N particles are much finer and the depth of the nitrided layer increases. There have phase relation, coherence and compatibility between γ'-Fe4N and α-Fe. spherical particles of cementite was formed in lower strip bainite, while the γ′ of gas nitriding diffusion layer is big, the carbide assumes the long strip off and with distributing certain directivity. Brittleness of laser hardening/ nitriding layer reduces.
Publisher
Trans Tech Publications, Ltd.
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