CONTROLLED COOLING AND CONTROLLED ROLLING METHOD FOR CONTROL OVER BEARING STEEL WIRE CARBIDE NETWORK

摘要

The invention relates to a method for controlling carbide network in a bearing steel wire rod by controlling cooling and controlling rolling, and the process is characterized by comprising the following steps: rapidly rolling a bar to a wire rod with a specified specification and spinning it into a loose coil, controlling the rolling temperature at 780°C-880°C; and the spinning temperature at 750°C-850°C; carrying out on-line controlling cooling of continuous loose coils using EDC water bath austempering cooling process, controlling the cooling rate at 2.0°C/s-10°C/s, and controlling the final cooling temperature within 620-630°C; after EDC water bath austempering cooling, using slow cooling under a cover, and the temperature is controlled to be 400°C-500°C when being removed out of the cover; after slow cooling, collecting coils, and cooling in air to the room temperature. EDC water bath austempering + slow cooling under a cover is used for controlling cooling of the coils, which effectively inhibits precipitation of carbide in the cooling process, so that non-equilibrium microstructure is obtained to form short-strip or hemispherical carbides, thereby finally controlling the carbide network.