Strengthening And Tougheningresearch On The Material ZG25Mn Of Axle-Box Base

Research on improve strengthening and toughening of steel on the application of the axle-box base in this article.Analyzing the crack type and crack initiation reason of the axle-box base of SS7C electric locomotive by fracture analysis on methods of SEM analysis and so on, the conclusion is obtained that the casting defects and the oxide compound mixture are the main reason of early fatigue cracks; Compares and analyzes the difference between overseas and domestic material of axle-box base in microstructures and mechanical properties, the results show that the overseas material has been entered into a little alloy elements to improve toughness such as Cr, Ni ,Mo and so on, and the contents of S and Mn are different to the domestic material, the microstructure is fine than the domestic material. Those are helpful to improve grain strengthening and solution strengthening, thus the yield strength and impact toughness are greater than the domestic material; Applying the strengthening and toughening theory, heat treatment process tests of normalizing, quenching and temperature tempering, double quenching are carried on the material ZG25Mn of the axle box base from SS7C electric locomotive. According to the results of microstructures and mechanical properties in specimen, the best heat treatment parameters are obtained by orthogonal design method and applied in production practice successfully; After double quenching processing, completely quenching + double-phase area quenching + high tempering, the strengthening and toughening effect is obvious in the axle box base, which has achieved the level of axle box base from French 8K electric locomotive.Overall, this article has carried the successful exploration on how applying the strengthening and toughening theory to solve actual production problems, and establishes the foundation on making high performance axle-box base part having independent intellectual property rights in our country.