Strengthening and toughening heat treatment method of hot work die steel 4Cr5MoSiV1

Abstract

The invention discloses a strengthening and toughening heat treatment method of hot work die steel 4Cr5MoSiV1, which is characterized by comprising the following steps of: 1, placing a steel material in a resistance furnace, setting the temperature to 850-870 DEG C, preserving the temperature for 60-90s per millimeter of steel material; 2, raising the temperature to 1090-1110 DEG C, preserving the temperature for 70-90s per millimeter of steel material, oil cooling or air cooling to room temperature; 3, then re-placing the steel material in the resistance furnace, raising the temperature to 700-720 DEG C, preserving the temperature for 90min, air cooling to room temperature; 4, placing the steel material in a salt bath furnace, raising the temperature to 940-960 DEG C, preserving the temperature for 60-90s per millimeter of steel material; 5, taking the steel material out and then rapidly placing in a salt bath furnace with a temperature of 730-750 DEG C, preserving the temperature for 60-90s per millimeter of steel material, then taking the steel material out and then rapidly placing in a salt bath furnace with a temperature of 940-960 DEG C, preserving the temperature for 60-90s per millimeter of steel material; 6, repeating the step 5 for 3-5 times, air cooling to room temperature; 7, placing the steel material in a tempering furnace, reducing the temperature to 600 DEG C, preserving the temperature for 90 min, air cooling to room temperature; and 8, placing the steel material in the tempering furnace again, reducing the temperature to 580 DEG C, preserving the temperature for 90min, and air cooling to room temperature to obtain the hot work die steel. The hot work die steel 4Cr5MoSiV1 has the advantages of remarkable refined grains, uniform microstructure, reduced large-size carbide and lightened banded structure.

Description

technical field [0001] The invention relates to a hot work die steel, in particular to a strengthening and toughening heat treatment method of the hot work die steel 4Cr5MoSiV1. Background technique [0002] Hot work die steel 4Cr5MoSiV1 has excellent hardenability, hardenability and good room temperature and high temperature properties, and is widely used in dies with high thermal fatigue tensile strength, good toughness, and temperatures <700 °C. [0003] At present, the traditional heat treatment process of hot work die steel 4Cr5MoSiV1 is as follows: anneal with the furnace temperature up to 850-870°C, heat it for a period of time, then cool it to 500°C in the furnace, then air cool; heat it again to 550-600°C for a period of time, continue heating to 800 -850°C for a period of time, continue to heat to 1030-1050°C for a period of time, oil cooling or air cooling, tempering at 600°C, then tempering at 580°C, if there is a special need for a third tempering treatment, ...

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Problems solved by technology

[0003] At present, the traditional heat treatment process of hot work die steel 4Cr5MoSiV1 is as follows: anneal with the furnace temperature up to 850-870°C, heat it for a period of time, then cool it to 500°C in the furnace, then air cool; heat it again to 550-600°C for a period of time, continue heating to 800 -850°C for a period of time, continue to heat to 1030-1050°C for a period of time, oil cooling or air cooling, tempering at 600°C, then tempering at 580°C, if there is a special need for a third tempering treatment, after The performance of 4Cr5MoSiV1 treated by the above heat treatment process basically meets the requirements for the use of common molds, but for large, precise, complex hot work die steels that need to be served under high temperature conditions for a long time, the above heat treatment process can no longer meet its use requirements. The segregation of carbides and banded structures is serious, which reduces the strength and toughness of hot work die steel 4Cr5MoSiV1

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