Quenching heat treatment process for hot work die steel with low heat resistance

A hot work die steel, heat resistance technology, applied in the direction of manufacturing tools, metal processing equipment, forging/pressing/hammer devices, etc., can solve the problem of insufficient cooling capacity of quenching oil, poor cooling capacity of quenching oil, and poor comprehensive mechanical properties Ideal and other issues

Active Publication Date: 2012-11-14
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the use of quenching oil as the cooling medium for quenching heat treatment of low heat-resistant hot work die steel in the prior art, for large-sized die steel, the quenching oil has poor cooling capacity and is easy to form in a large area of ​​the core of the die steel The upper bainite structure leads to unsatisfactory compr

Method used

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  • Quenching heat treatment process for hot work die steel with low heat resistance
  • Quenching heat treatment process for hot work die steel with low heat resistance
  • Quenching heat treatment process for hot work die steel with low heat resistance

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The weight of the smelted and poured steel ingot is 140t. After two upsetting and drawing processes, it is processed into a die steel with a size of 3000mm × 1000mm × 800mm. After chemical analysis, its specific composition is shown in Table 1.

[0026] Table 1* Chemical composition of low heat resistance hot work die steel in Example 1 (weight percent, %)

[0027] element

C

Si

Mn

P

S

Cr

Mo

Ni

V

Ingredient Specifications

0.4～0.6

0.1～0.5

0.6～1.0

≤0.01

≤0.01

0.9～1.3

0.4～0.6

1.4～2.0

0.06～0.1

Measured ingredients

0.54

0.20

0.74

0.008

0.005

1.06

0.48

1.58

0.086

[0028] *Ac3 of this ingredient is 715°C.

[0029] The quenching and heat treatment process for low heat resistance hot work die steel is as follows:

[0030] 1) Heating: Heating at a slow heating rate of 80℃ / h to ...

Embodiment 2

[0035] The weight of the smelted and poured steel ingot is 215t. After two upsetting and drawing processes, it is processed into a die steel with a size of 3800mm×1500mm×1300mm. After chemical analysis, its specific composition is shown in Table 2.

[0036] Table 2 Chemical composition of low heat resistance hot work die steel in Example 2 (weight percent, %)

[0037] element

C

Si

Mn

P

S

Cr

Mo

Ni

V

Ingredient Specifications

0.4～0.6

0.1～0.5

0.6～1.0

≤0.01

≤0.01

0.9～1.3

0.4～0.6

1.4～2.0

0.06～0.1

Measured ingredients

0.45

0.35

0.85

0.005

0.005

1.20

0.55

1.70

0.07

[0038] *Ac3 of this ingredient is 760°C.

[0039] The quenching and heat treatment process for low heat resistance hot work die steel is as follows:

[0040] 1) Heating: Heating at a slow heating rate of 50℃ / h to the a...

experiment example 1

[0057] The low heat resistance hot work die steels in Examples 1, 2 and Comparative Examples 1 and 2 after heat treatment were sampled respectively on the surface and about 150 mm below the surface, and the mechanical properties were measured. The specific values ​​are shown in Table 3. .

[0058] Table 3 Mechanical properties detection of the embodiments of the present invention and comparative examples

[0059]

[0060] It can be seen from the results that the strength properties and impact toughness of the samples in Examples 1 and 2 are significantly better than those in the corresponding Comparative Examples 1 and 2, and no low resistance is seen in Examples 1 and 2. Hot hot work die steel has serious deformation and quenching cracking. It shows that the present invention achieves the purpose of improving the mechanical properties of the material.

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Abstract

The invention relates to the field of heat treatment technology and provides a quenching heat treatment process for low-heat resistance hot work die steel which has low content of alloy and costs little in production and especially for low-heat resistance hot work die steel with a great tonnage and a great size. The process overcomes the problem that insufficient cooling capability of quenching oil causes generation of abundant upper bainite structures, which further leads to deterioration of the performance of steel. The quenching heat treatment process comprises the following steps: heatingthe low-heat resistance hot work die steel and carrying out insulation and full austenization on the low-heat resistance hot work die steel; carrying out segmented quenching heat treatment by using different cooling mediums at different temperatures; and carrying out tempering heat treatment immediately after surface temperature of the low-heat resistance hot work die steel drops to a certain range. According to the invention, a high cooling rate and low residual stress are obtained through a segmented quenching technique based on characteristics of changes of a microstructure of the low-heatresistance hot work die steel in the process of continuous cooling, and therefore, generation of abundant upper bainite structures in the low-heat resistance hot work die steel and the phenomena of deformation and cracking during quenching heat treatment are avoided and the purposes of improving comprehensive mechanical properties and prolonging a service life are achieved.

Description

technical field [0001] The invention relates to the technical field of heat treatment of steel, in particular to a quenching heat treatment process of low heat resistance hot work die steel. Background technique [0002] Low heat resistance hot work die steel is mainly used in the production of forging dies and hammer forging dies. The cyclic impact force of large forging dies in service reaches hundreds of MN. Due to the contact with high temperature metal (800 ℃ ~ 1200 ℃), the temperature of the forging dies can reach 300 ℃ ~ 500 ℃. Therefore, forging dies with low heat resistance heat In addition to high hardenability, high temperature strength, impact toughness and tempering resistance stability, die steel must also have good fatigue resistance and thermal conductivity to ensure that the forging die will not generate heat under the conditions of rapid cooling and rapid heating. cracked. In recent years, with the rapid development of my country's equipment manufacturing...

Claims

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Application Information

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IPC IPC(8): C22C38/46C21D1/18B21J13/02
Inventor 樊梦婷孙明月李殿中
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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