High-temperature-resistant and high-toughness hot work die steel and preparation method thereof

Abstract

The invention relates to the technical field of special steel forgings, in particular to high-temperature-resistant and high-toughness hot work die steel and a preparation method thereof. The hot workdie steel comprises the following components of, in percentage by weight, 0.38 %-0.40% of C, 0.25 %-0.40 % of Si, 0.45 %-0.55 % of Mn, 4.75 %-5.3 % of Cr, 1.7 %-1.9 % of Mo, 0.60 %-0.80 % of V, 0.30%-0.50 % of Ni, less than or equal to 0.002 % of S, less than or equal to 0.0015 % of P, and the balance Fe. The preparation method comprises the following steps of electric arc furnace smelting, external refining, casting, atmosphere protection electroslag remelting, forging, quenching oil cooling treatment and spheroidizing annealing treatment. According to the steel and the method, the raw material proportion of the hot work die steel is optimized, and the content of Si, V, Mo, Ni and other elements is limited within an accurate adjustment and control range, so that the adding amount of corresponding Si, V, Mo, Ni and other elements can be accurate, and the problem that all properties of the die steel are incompatible is solved; and the high-performance hot work die steel can be directly manufactured by selecting the numerical value of the content within the range, so that the finished product rate is remarkably increased.

Description

technical field [0001] The invention relates to the technical field of special steel forging technology, in particular to a high-temperature-resistant and high-toughness hot work die steel and a preparation method thereof. Background technique [0002] Hot work die steel mainly refers to the alloy tool steel used in the mold for thermal deformation processing of metals, such as hot forging dies, hot extrusion dies, die-casting dies, hot heading dies, etc. Since the hot work mold works under high temperature and high pressure conditions for a long time, the mold material is required to have high strength, hardness and thermal stability, especially high thermal strength, thermal fatigue resistance, toughness and other properties. Mold processing has a series of advantages such as high production efficiency, good quality, material saving and low cost. It has a wide range of applications. Hot work die steel refers to the alloy steel used in molds suitable for thermal deformation...

AI Technical Summary

Problems solved by technology

At present, hot work dies are developing in the direction of large size, precision, and long life, which puts forward higher requirements for the performance of hot work die steel, and H13 steel can no longer meet customers' requirements for the use of die performance

[0003] In view of the above problems, the existing prior art publication number is: CN110306108A, and the title is: a high toughness and high crack resistance hot work die steel and its manufacturing method. In this invention, it is beneficial to control the content of Si and V in the die steel. The primary carbide type can weaken the influence of primary carbide on the subsequent process and product performance, and improve the toughness of die steel; adding Mo element can improve the high temperature strength, tempering resistance stability and cold and heat fatigue performance of the material; adding Ni element Alloying reduces the temperature of the transformation point and lowers the critical cooling rate for obtaining martensite, so that the die steel can obtain higher hardenability and impact toughness, thereby obtaining better comprehensive performance; The composition requirements are extremely strict. If the contents of Si, V, Mo and Ni are not adjusted properly, the high toughness, high hardness, thermal cracking resistance, high hardness and machinability of hot work die steel cannot be compatible. The composition range of the hot work die steel provided is too large, for example, when the content of Mo element is increased, but the values ​​in the selection range of Si, V and Ni elements are inappropriate, although the die steel has higher strength and hardness, it will reduce Machinability of the tool makes it difficult to cut the die steel. At the same time, the subsequent heat treatment process is forced to change, thereby affecting the performance of the product. The preparation method provided by the invention cannot directly produce high-performance hot work die steel. The finished product low rate

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