所属分类：公司动态 发布时间：2021-04-17 15:25:02 来源：http://www.lcnmb500.com 浏览量：
The retained austenite of the wear-resistant composite lining plate is distributed between martensite and lath in the intersection zone, most of which are flakes, and the thickness is about 50-200 nm. With the increase of distribution time, the width of retained austenite film decreases.
Because the shape of retained austenite in wear-resistant composite liner is affected by martensitic transformation and morphology, martensitic transformation continues to occur during isothermal process, and the thickness of martensitic lath continues to increase. The effect of different process parameters on the microstructure of wear-resistant composite liner was studied.
The microstructure was characterized by optical microscope, scanning electron microscope, electron backscatter diffraction, X-ray diffraction and transmission electron microscope. The change of matrix structure and the relationship between the morphology, distribution and content of retained austenite and process parameters were studied. A treatment process of over 20000 MPa% for strong plastic products was designed.
The main work and research results are as follows: at the same partition temperature, with the extension of partition time, the laths in martensite region become thicker, the characteristics of laths become less obvious, and the interface between laths is not sharp, but curved. This is caused by the migration of martensite / austenite interface and the tempering transformation of martensite matrix during QP treatment.
With the increase of holding time, the number of carbide particles between the strips of the wear-resistant composite liner increased significantly, and the distribution temperature of the two-step QP treatment increased to 450. The carbide particles still exist in the martensite lath of the wear-resistant composite liner, but the amount is obviously reduced. It can be inferred that most of the carbide particles are transition carbides at lower distribution temperature, and are relatively restrained at 450.
At the same temperature and time, the volume fraction of retained austenite obtained by two-step QP heat treatment is higher than that by one-step QP heat treatment. The distribution efficiency and volume fraction of retained austenite can be effectively improved by optimizing the processing parameters of 400 wear resistant composite liner.