Steel with ultra-high thermal conductivity for hot-stamping die and preparation method of steel

Abstract

The invention relates to a novel material with ultra-high thermal conductivity for a hot-stamping die. The steels in the market for the hot-stamping die are mainly various types of improved H13 and H11 high-alloy hot work die steels. The steel in the invention comprises the following compositions in percentage by mass: 0.150-0.35% of C, less than or equal to 0.25% of Si, 0.08-0.20% of Mn,1.0-2.0% of W,2.0-4.5% of Mo, less than or equal to 0.30% of Cr,less than or equal to 0.02% of V and the balance of Fe and inevitable impurity elements, wherein S in the impurity elements is less than or equal to 0.005%, P in the impurity elements is less than or equal to 0.01 and O in the impurity elements is less than or equal to 30 ppm (parts per million). The invention is characterized in that simple elements i.e. C, Mo and W are used as the main elements, and proper proportion of carbide is adopted; the contents of Mn and Cr are maintained low, and the content of Si is maintained ultra-low; the steel has superior machining property after being subjected to electro-smelting, electro-slag remelting, annealing, high-temperature homogenization, forging and annealing; through thermal treatment (1060-1100 DEG C quenching and high-temperature annealing), the toughness of the steel can reach the toughness of common hot-stamping die steel such as H13, and the hardness, annealing stability and the fatigue property of the steel are more superior; particularly, the steel with lower coefficient of thermal expansion and ultra-high thermal conductivity is more suitable for hot stamping.

Description

technical field [0001] The invention relates to a steel for an ultra-high thermal conductivity hot stamping die and a preparation method thereof. Background technique [0002] According to the service conditions of the mold, the mold steel can be roughly divided into three categories: cold work mold steel, hot work mold steel and plastic mold steel. Hot stamping die steel belongs to hot work die steel. With the rapid development of the automobile industry and the continuous improvement of the demand for lightweight automobiles, the hot stamping forming process is mainly used to obtain ultra-high-strength stamping parts. When obtaining ultra-high-strength steel, due to the extremely high forming force required by the cold stamping forming process, it is easy to cause mold damage, equipment vibration, and problems such as cracking, wrinkling, rebound, and poor dimensional accuracy. Therefore, the original cold stamping forming process no longer meets the needs of technology...

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Problems solved by technology

[0016] 3) Compared with the present invention, the chemical composition of patent CN200810101341.2 adds Nb (0.08-0.15%) element. Nb element is mainly solid-dissolved in the matrix, and the distribution is uniform, which plays the role of solid-solution strengthening, and in the long-term During heat preservation, Nb in the material structure is dispersed and precipitated from the matrix to NbC, which enhances the temper softening resistance of the material; it contains a relatively high content of 4.8-5.2% of chromium and 0.9-1.1% of silicon, which can form a dense oxide film to improve the oxidation resistance of steel Addition of less than 6% chromium is beneficial to improve tempering resistance, but it fails to form secondary hardening

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