High-performance hot stamping die steel and manufacturing process thereof

Abstract

The invention relates to high-performance hot stamping die steel and a manufacturing process thereof. The high-performance hot stamping die steel comprises the following components of, in percentage by mass, 0.66% - 0.80% of C, 0.80% - 1.20% of Si, 0.20% - 0.50% of Mn, 5.00% - 6.50% of Cr, 1.50% - 2.00% of Mo, 0.40% - 0.80% of V, less than 0.015% of P, less than 0.015% of S and the balance Fe. Themanufacturing process of the die steel comprises the following steps of carrying out burdening, smelting, casting, electroslag remelting; carrying out high-temperature diffusion thermal treatment, multi-direction forging and hot machining and cooling control after forging; then carrying out secondary carbide refining thermal treatment and isothermal annealing treatment; and finally carrying out quenching and tempering thermal treatment. The high-performance hot stamping die steel and the manufacturing process thereof has the advantages that the hardenability, the thermal stability, the wear resistance and the thermal fatigue performance of the hot-work die steel are superior to the hardenability, the thermal stability, the wear resistance and the thermal fatigue performance of H13 steel,and the hot-work die steel can be machined into a large-scale hot stamping die with the single-piece weight reaching 5 tons or above, and the usability is good.

Description

technical field [0001] The invention belongs to the technical field of alloy steel and relates to a hot stamping die steel, in particular to a high-performance hot work die steel and its manufacturing process. Background technique [0002] Hot work die steel is a die steel used at higher temperatures (generally higher than 500 ° C), in which the alloying elements that play high temperature thermal strength and thermal stability are usually Cr, Mo, V and other alloying elements, so the current Some of the research work is mainly on the adjustment of these alloying elements. This study found that the addition of a higher content of Mo element can improve the thermal fatigue resistance and temper softening resistance of steel, and the addition of a certain amount of V element can greatly improve the thermal stability and thermal fatigue resistance of steel, so that The service temperature of the steel is greatly increased, and the higher C content can significantly improve the...

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Problems solved by technology

4Cr5MoSiV1 steel is the most widely used hot work die steel, but its high temperature strength is not very high, the general use temperature can not exceed 540 ℃, and the thermal fatigue resistance and wear resistance are not high

This manufacturing process has the following problems: 1) The size of the electroslag ingot is small, and the small ingot type reduces the yield and manufacturing capacity of the product; 2) The original structure of the electroslag ingot has a large number of large particles or large blocks of liquefied carbonization 3) The grain size of the material after forging is coarse, resulting in low impact toughness of the material after quenching and tempering, and low product grade, which cannot meet the market demand for large cross-section, high toughness, and high heat. The need for strong hot work die steel; 4) The hydrogen expansion annealing time after forging is long, and it is prone to flaw detection defects such as white spot cracks

[0005] In view of the above phenomenon, the patent CN 109280849A discloses a high-performance hot work die steel and its manufacturing process. The composition and mass percentages of the high-performance hot work die steel are as follows: C 0.20-0.30%, Si 0.40-0.80 %, Mn 0.40-0.80%, Cr 3.10-4.00%, Mo 1.60-2.00%, W 0.50-1.00%, V 0.10-0.30%, P<0.010%, S<0.005%, Fe balance; the invention die steel The manufacturing process is as follows: batching, smelting, pouring, and then electroslag remelting; high temperature diffusion heat treatment, then multi-directional forging heat processing, and controlled cooling after forging; and then secondary carbide refining heat treatment and isothermal annealing treatment Carry out quenching and tempering heat treatment at last; The advantage of this invention is: the hardenability, thermal stability, impact toughness and thermal fatigue performance of the hot work die steel of this invention are better than H13 steel, and can be processed into single piece weight to reach 5 The large die-casting mold with more than 1 ton has good performance; in addition, it can reduce the cost of steel ingot smelting and improve the service life of the mold; but this invention patent still has certain defects: the content of carbon in the steel of this invention is low, which cannot meet the requirements of steel strength and hardness requirements

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