Hot work die steel with good high-temperature toughness and strong thermal fatigue resistance and preparation method thereof

Abstract

The invention discloses hot work die steel with good high-temperature toughness and strong thermal fatigue resistance and a preparation method thereof. The hot work die steel comprises the following components in percentage by weight: 0.38 to 0.45 percent of C, 0.10 to 0.23 percent of Si, 0.20 to 0.40 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.003 percent of S, 5.0 to 5.6 percent of Cr, 0.70 to 0.95 percent of Ni, 1.95 to 2.20 percent of Mo, 0.60 to 0.75 percent of V, 0.10 to 0.18 percent of Re, 0.10 to 0.20 percent of Nb and the balance of Fe. Compared with traditional H13 steel, the die steel is superior in tempering stability at 620 to 700 DEG C, oxidation resistance, thermal wear resistance at 800 to 950 DEG C, thermal fatigue resistance at 650 DEG C and 750 DEG C, free-cutting machinability and forgeability; and particularly, a metallographic structure obtained after forging and annealing is very ideal and reaches the A1, A2, B1 and B2 levels of the NADCA standard of the North American Die Casting Association, and conditions are created for final heat treatment of dies, so that excellent comprehensive mechanical properties are obtained.

Description

technical field [0001] The invention relates to the technical field of hot work die steel materials, in particular to a hot work die steel with good high-temperature strength and toughness and strong thermal fatigue resistance and a preparation method thereof. Background technique [0002] 8418 hot work die steel is a high-quality hot work die steel developed by ASSAB in Sweden. It adopts the latest production and refining technology, so that DIEVAR, as the latest development of die casting die steel, has excellent thermal fatigue cracking , thermal shock cracking, thermal wear, plastic deformation performance. These unique properties make it the best choice for die casting, hot forging, and hot extrusion die steel. In addition: during the punching process, the mold must have a certain degree of toughness. When punching thick plates and steel strips, the punching edge of the die will bear high tensile stress, so the die must have high toughness so as not to crack. The thi...

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Problems solved by technology

[0004] The purpose of the present invention is to aim at the hot work dies whose high-temperature strength, toughness, high-temperature hardness, thermal stability, thermal fatigue resistance, crack bridge resistance, and anti-explosion mode characteristics of the existing 8418 hot work die steel cannot meet the harsh conditions of use. , such as hot extrusion dies for black and non-ferrous metal materials, copper-aluminum die-casting dies, and precision forging dies, etc., to provide a hot-work die steel with good high-temperature strength, toughness, and strong thermal fatigue resistance and its preparation method