Die steel and preparation method thereof

Abstract

The invention provides die steel and a preparation method thereof, and belongs to the technical field of die steel. The preparation method of the die steel is characterized by comprising the following steps that S1, raw material treatment is conducted, specifically, burdening is conducted according to mass-percent components of the die steel, a conventional method is adopted for smelting, cooling and demolding, and a steel ingot is obtained; S2, remelting and refining are carried out, specifically,the steel ingot is remelted at the temperature of 1100-1400 DEG C for 4-5 hours; in the machining process, an electrode is buried in a shallower position and forms a shallower molten pool, and after crystallization is conducted for preset time, forced cooling is conducted on the lower portion of the remelted steel ingot; S3, primary annealing treatment is carried out, specifically, a spheroidizing annealing process is carried out; S4, forging is conducted, specifically, forging, upsetting and drawing-out are conducted through a hydraulic press, the initial forging temperature is 1180 DEG C, and the final forging temperature is 950 DEG C; S5, secondary annealing treatment is conducted, specifically, a spheroidizing annealing process is conducted after normalizing; and S6, finish machining is conducted, specifically, grinding tool steel is obtained after finish machining.

Description

technical field [0001] The invention belongs to the technical field of die steel, in particular to a die steel and a preparation method thereof. Background technique [0002] In the actual production process of the hot work die, the high temperature liquid metal and other media that reduce the temperature of the liquid metal will be mixed in the cavity of the hot work die steel, so that the hot work die is subjected to the cyclic heating and cooling process, which will also cause the hot work die to be heated and cooled in a cyclic state. The hot work die produces the effect of thermal expansion and cold contraction. When stamping a high temperature workpiece, the contact surface between the cavity of the hot work die and the high temperature workpiece will generate relatively complex tensile strain and tensile stress. When separated from the high temperature workpiece, the hot work die The temperature inside the cavity will drop rapidly, so compressive strain and compressiv...