Hot-rolled round steel process for preventing mixed crystal of refined grains of hub bearing steel

The invention discloses a round steel hot rolling process for preventing mixed crystal of refined grains of steel for hub bearings, and relates to the technical field of steel production. The preheating section is less than or equal to 800 DEG C, the first heating section is less than or equal to 950 DEG C, the second heating section is 1030 +/-20 DEG C, the first soaking section is 1030 +/-20 DEG C, and the second soaking section is 1030 +/-20 DEG C; through on-line rolling and 7 water tank water cooling, the final rolling in a rolling mill is controlled to be 790-810 DEG C, and the target rolling is 800 DEG C; and slowly cooling to 750-770 DEG C in a heat insulation cover on a cooling bed at the target temperature of 760 DEG C, and then air cooling. Large pearlite group structures and core martensite are eliminated through grain refining and mixed crystal preventing processes, the impact toughness of the material can be greatly improved, the service life of the material is prolonged, the safety of the mater