The invention relates to a
quenching method of an integral cast steel supporting roll, which is an improvement of the
quenching method of the working layer of the integral cast steel supporting roll, and the method is characterized in that the integral heating of the supporting roll comprises the following steps: first, heating the quenched and tempered supporting roll according to a heating rate of less than or equal to 20 DEG C / h to the temperature which is 50-100 DEG C below the cotectic curve temperature, and keeping temperature for 13D-20D; transferring the supporting roll into a
differential heating furnace, quickly heating the supporting roll according to the heating rate of greater than or equal to 250 DEG C / h under
slow rotation until the surface temperature is greater than or equal to the
quenching temperature, and keeping temperature until the thermoosmosis thickness is greater than or equal to the required depth of the hardening layer; transferring the roll into a water quenching
machine, carrying out rotating
water spray quenching when the surface temperature is greater than or equal to 850 DEG C at the
cooling rate of greater than or equal to 2 DEG C / s for the spray quenching of the roll, and stopping spraying water when the surface temperature is less than or equal to 220 DEG C; and transferring the roll into a
heating furnace for
tempering treatment to obtain the roll of which the surface
hardness is 55-75HSD, the uniformity of the surface
hardness is less than or equal to + / -1HSD, the radial
hardness drop of the hardening layer is less than or equal to 0.5HSD / cm, and the tensile strength of the hardening layer is greater than or equal to 1200MPa. Compared with the prior art, the invention has high hardness of the working layer, good hardness uniformity, good hardening capacity, controllable depth of the hardening layer and small radial hardness drop.