Analysis of quality stability level of Cr-Ni-Mo automotive gear steel

In order to promote the transformation and development of China towards a manufacturing power house,the materials for key components in the manufacturing industry must have high quality stability while continuously improving their performance. For example,when promoting the development of high-grade automobiles in China,the materials used for automobile gear parts must possess high quality and sufficient quality stability at the same time. The Cr-Ni-Mo gear steel is a very important product in automotive gear steel,which has the characteristics of high bearing capacity and good impact resistance,and is widely used. Therefore,the Cr-Ni-Mo automotive gear steel is taken as the research object. According to the research and analysis of the smelting composition,bloom segregation,product segregation,hardenability and band structure control of the gear steel,the advanced quality stability control level of domestic Cr-Ni-Mo automobile gear steel has been acquired,and its influence on gear manufacturing has been analyzed. The results show that the smelting composition of Cr-Ni-Mo automobile gear steel in a domestic special steel plant can be accurately controlled during industrial production. The fluctuation of C mass percent at the refining end is controlled within ±0.01%,and the fluctuation of Mn,Cr,Ni mass percent is controlled within ±0.02%. The C segregation in the section of finished bar is very small. The proportion of heats with C mass percent fluctuation below 0.02% reaches 97%. In addition,the narrow hardenability bandwidth and low banded structure grade can be also stable achieved. The hardenability bandwidth is basically controlled below 4HRC,and the banded structure is stably controlled below 1.5 grade. Therefore,the advanced Cr-Ni-Mo automobile gear steel in China can achieve the level of high quality and high stability,and it will play an important role in the safety of heavy vehicles.