Solid nitriding process for low-deformation surface strengthening of hot die steel

A solid nitriding process for low-deformation surface strengthening of hot mold steel comprises the following steps: embedding a hot mold steel workpiece into a stainless steel protection tank filled with granular charcoal, putting the stainless steel protection tank into a hearth of a crucible furnace heated to 800 DEG C, continuously heating to 1000-1100 DEG C, keeping the constant temperature, and carrying out oil immersion cooling to room temperature; then putting into a hearth of a crucible furnace with the cooled first tempering temperature, carrying out first tempering, carrying out oil immersion cooling to room temperature, putting into a stainless steel infiltration tank together with a solid nitriding agent, and sealing a tank cover by using mixed pug prepared from bentonite, water glass and water; and putting into a hearth of a crucible furnace which is heated to 570-580 DEG C for heat preservation, and carrying out oil immersion cooling to room temperature, so as to obtain the high-hardness and hi