Basic Criteria for Chemical Composition Design of GCr15 Steel

At the beginning of the birth of the modern bearing industry, bearings were mainly made of carbon steel and carburized steel. The smelting technology of carbon steel is mature and the price is low, but its comprehensive performance cannot meet the requirements of the bearing's service characteristics. Carburized steel is hard on the outside and tough on the inside, and has gradient properties suitable for complex loads. However, due to the limitations of the solid carburizing method used at that time, the individual soft spots caused by uneven carburizing greatly reduced the bearing life, and the heat treatment process was complicated. Production The cycle is long, the efficiency is low and the cost is high. Therefore, research and development of special steel grades suitable for mass production of bearings has become an urgent need. The invention of GCr15 steel is a major breakthrough based on carbon steel. The main chemical composition of GCr15 and equivalent grades of bearing steel is mainly carbon and chromium. Except for carbon, the mass fraction of other alloying elements is less than 3%. It is a high-carbon, low-chromium, low-alloy, hypereutectoid steel. The basic criteria embodied in the design of the chemical composition of GCr15 steel are performance, manufacturability and economy.