High-temperature, high-strength and low-carbon hot work die steel and preparation method thereof

A high-temperature, high-strength technology, applied in the field of low-carbon hot-work die steel and its preparation, can solve the problems of lowering the high-temperature strength and red hardness of the material, affecting the toughness and fatigue performance of the hot-working die steel, and reducing the service life of the die.

Inactive Publication Date: 2019-03-19
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] However, the above-mentioned new hot die steel is still not suitable for high-temperature working conditions above 600°C. When the working temperature is higher than 600°C, its high-temperature strength and thermal stability will drop sharply, resulting in a sharp decline in the service life of the mold.
The reason is that when the temperature rises above 600 °C, the coherent relationship between the matrix and the second phase is destroyed, and part of the strengthening effect of M 2 C-type carbides dissolve back, and some Cr carbides have poor thermal stability and grow rapidly, which makes the high-temperature strength and red hardness of the material decrease rapidly
In order to improve the high-temperature stability of the material matrix and the second phase, the method of increasing the carbon content and alloy element content is usually used, but due to the increase in the carbon content and alloy element content, it is easy to cause the formation of acicular martensite and the formation of carbides. Coarsening, which will seriously affect the toughness and fatigue properties of hot work die steel, and is also not conducive to the service life of the die

Method used

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  • High-temperature, high-strength and low-carbon hot work die steel and preparation method thereof
  • High-temperature, high-strength and low-carbon hot work die steel and preparation method thereof
  • High-temperature, high-strength and low-carbon hot work die steel and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Place the 1# ingot in a gas furnace and heat it to 1250°C for homogenization annealing for 20 hours, then cool it with the furnace at a rate of 100°C / h to below 500°C and leave the furnace for air cooling; heat it to 1160°C with a trolley and keep it for 4 hours . After the heat preservation is completed, forging is carried out. The initial forging temperature is about 1130°C, the final forging temperature is 810°C, the first heat forging is to Φ90, and the forging ratio is 3.3; Heat to 870°C at a heating rate greater than 100°C / h, hold for 150 minutes, and then cool with the furnace at a rate of 30°C / h to below 500°C and leave the furnace for air cooling. After the 1# steel and the comparison steel were annealed, they were processed into samples, quenched after being kept at 980°C for 60 minutes, and then tempered at 640°C for 2 hours, then the mechanical properties were tested. Compared with the comparison steel, the structure of 1# steel is finer than that of the se...

Embodiment 2

[0051] Place 2# and 3# steel ingots in a gas furnace and heat them to 1280°C for homogenization annealing for 30 hours, then cool with the furnace at a rate of 90°C / h to below 500°C and leave the furnace for air cooling; heat to 1180°C with a trolley Keep warm for 4 hours. After the heat preservation is completed, forging is carried out. The initial forging temperature is about 1150°C, the final forging temperature is 830°C, the first fire forging is to Φ90, and the forging ratio is 3.3; Heat to 870°C at a heating rate greater than 100°C / h, hold for 150 minutes, and then cool to 500°C with the furnace at a rate of 30°C / h, then take out the furnace and air cool. After annealing 2#, 3# steel and the comparison steel, they were processed into samples, and quenched after being kept at 1050°C for 60 minutes, and then tempered at 640°C for 2 hours, then the mechanical properties were tested. Compared with the comparison steel, 2# and 3# steel have finer structure than the second st...

Embodiment 3

[0063] Put the 4# ingot in a gas furnace and heat it to 1300°C for homogenization annealing for 20 hours, then cool it with the furnace at a rate of 80°C / h to below 500°C and leave the furnace for air cooling; heat it to 1200°C with a trolley and keep it for 4 hours . After the heat preservation is completed, forging is carried out. The initial forging temperature is about 1180°C, the final forging temperature is 850°C, the first fire forging is to Φ90, and the forging ratio is 3.3; Heat to 870°C at a heating rate greater than 100°C / h, hold for 150 minutes, and then cool to 500°C with the furnace at a rate of 30°C / h, then take out the furnace and air cool. After the 4# steel and the comparison steel were annealed, they were processed into samples, quenched after being kept at 1050°C for 60 minutes, and then tempered at 640°C for 2 hours, then the mechanical properties were tested. Compared with the comparison steel, the structure of 4# steel is finer than that of the second t...

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Abstract

The invention discloses hot work die steel capable of being used for a long term at the working condition of 600-700 DEG C and belongs to the field of material and preparation. The hot work die steelcomprises the following components in percentage by mass: 0.12-0.30 of C, equal to or less than 0.5 of Si, equal to or less than 0.5 of Mn, 1.0-3.0 of Cr, 1.5-2.5 of Mo, 0.3-1.2 of W, 0.5-1.6 of Ni, 0.2-1.0 of V, 0.03-0.15% of Nb, equal to or less than 0.05 of N, equal to or less than 0.03 of S, equal to or less than 0.03 of P, equal to or less than 3.5 of (Mo+W), equal to or less than 1.0 of (Nb+V) and the balance of Fe and unavoidable impurity elements. According to the hot work die steel, low carbon is adopted to form lath martensite so as to obtain high tenacity at room temperature and lowtemperature; through alloying of Cr, W, Mo, V, Nb and the like and the thermal deformation optimization and thermal treatment technology, solution strengthening is improved and MC and M2C type carbide still keeping stability at 600-700 DEG C is formed so as to obtain high temperature strength and thermal stability of the material. Compared with the commonly used hot work die steel at present including H13, 25Cr3Mo3NiNbZr and the like, the high temperature strength at 700 DEG C of the hot work die steel is improved by 50-100%, the tempering thermal stability is improved by 50-100%, the problemabout hot work die steel used at 600-700 DEG C is better solved, and the hot work die steel has longer service life at 600 DEG C and below.

Description

technical field [0001] The invention belongs to the field of materials and preparation, and in particular relates to low-carbon hot work die steel and a preparation method thereof. Background technique [0002] Hot mold steel is mainly used for molds used in various high temperature conditions, and special components under high temperature. Hot work die steel is divided into hot forging die, hot extrusion die, die casting die and hot blanking die. Among them, the working conditions of hot forging die and hot extrusion die are the most typical. Under a certain degree of load, the red-hot solid metal is plastically deformed. As high as 500°C-600°C, the local temperature is even as high as 700°C, and it bears a certain load. Under the periodic impact of strong load, it is easy to soften, collapse, and deform. Another important performance parameter. [0003] H13 steel is a commonly used traditional mold material and has a large domestic demand. However, with the rapid develo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/44C22C38/46C22C38/48C22C33/06C21D1/32C21D1/18C21D8/00
CPCC21D1/18C21D1/32C21D8/005C22C33/06C22C38/001C22C38/002C22C38/02C22C38/04C22C38/44C22C38/46C22C38/48
Inventor 黄进峰张津连勇张尊君张程李建强
Owner UNIV OF SCI & TECH BEIJING
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