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Thermal treatment and plasma nitrocarburizing surface treatment process method for special wear-resistant die steel with ultrahigh heat conductivity for hot stamping

A technology of plasma nitrogen and process method, applied in metal material coating process, coating, solid-state diffusion coating and other directions, can solve the problems of poor impact toughness, hardness drop, nitride structure, etc.

Inactive Publication Date: 2014-11-19
SHANGHAI UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0022] 2. Tempering temperature 560-600℃: After quenching, the carbon content of the austenite of the mold steel has increased, and a certain amount of austenite remains after quenching, and this part of the residual austenite is decomposed into martensite after one tempering , resulting in poor impact toughness
As the nitriding time prolongs, the diffusion layer deepens, and the hardness gradient tends to be gentle; but the increase of the holding time will cause the nitride structure to become rough, resulting in a decrease in hardness

Method used

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  • Thermal treatment and plasma nitrocarburizing surface treatment process method for special wear-resistant die steel with ultrahigh heat conductivity for hot stamping
  • Thermal treatment and plasma nitrocarburizing surface treatment process method for special wear-resistant die steel with ultrahigh heat conductivity for hot stamping
  • Thermal treatment and plasma nitrocarburizing surface treatment process method for special wear-resistant die steel with ultrahigh heat conductivity for hot stamping

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] The invention relates to a heat treatment and surface treatment process of a high-strength steel plate and a special ultra-high thermal conductivity wear-resistant die steel for hot stamping of tubes. The specific process is as follows:

[0044] 1. Chemical composition of mold material: C: 0.36%; Si: 0.07%; Mn: 0.14%; W: 1.70%; Mo: 4.51%;

[0045] Cr: 0.12%; V: 0.14%;

[0046] 2. Heat treatment process: Quenching at 1080°C, tempering at 560°C, 580°C, and 600°C for 2 hours. Under the heat treatment process conditions, the hardness and impact toughness: the hardness value is 51-53HRC, and the impact toughness value is 170-200 J. Quenched and tempered microstructure such as figure 1 shown.

[0047] 3. Plasma nitriding process: voltage 600-650V, atmosphere ratio NH 3 : CO2=10:1, furnace pressure 450-500Pa, nitriding temperature 520℃, nitriding time 8h. Surface hardness after nitriding is 760-800HV 0.3 , The thickness of the compound layer is 6-9μm. The cross-section ...

Embodiment 2

[0049] The invention relates to a heat treatment and surface treatment process of a high-strength steel plate and a special ultra-high thermal conductivity wear-resistant die steel for hot stamping of tubes. The specific process is as follows:

[0050] 1. Chemical composition of mold material: C: 0.38%; Si: 0.06%; Mn: 0.12%; W: 1.65%; Mo: 4.43%;

[0051] Cr: 0.12%; V: 0.13%;

[0052] 2. Heat treatment process: Quenching at 1080°C, tempering at 560°C, 580°C, and 600°C for 2 hours. Under the heat treatment process conditions, the hardness and impact toughness: the hardness value is 51-53HRC, and the impact toughness value is 170-200 J.

[0053] 3. Plasma nitriding process: voltage 800-850V, atmosphere ratio NH 3 : CO2=16:1, furnace pressure 450-500Pa, nitriding temperature 550℃, nitriding time 8h. Surface hardness after nitriding is 800-840HV 300 , the thickness of the compound layer is 11-15 μm. The cross-section structure picture of nitrocarburizing sample is as follows: ...

Embodiment 3

[0055] In this example, a special ultra-high thermal conductivity wear-resistant die steel for hot stamping is carried out for heat treatment and surface treatment. The specific process is as follows:

[0056] 1. Chemical composition of mold material: C: 0.37%; Si: 0.08%; Mn: 0.12%; W: 1.65%; Mo: 4.43%; Cr: 0.20%; V: 0.12%;

[0057] 2. Heat treatment process: Quenching at 1080°C, tempering at 560°C, 580°C, and 600°C for 2 hours. Under the heat treatment process conditions, the hardness and impact toughness: the hardness value is 51-53HRC, and the impact toughness value is 170-200 J.

[0058] 3. Plasma nitriding process: voltage 800-850V, atmosphere ratio NH 3 : CO2=10:1, furnace pressure 650-750Pa, nitriding temperature 550℃, nitriding time 12h. Surface hardness after nitriding is 820-850HV 300 , compound layer thickness 12-17μm. The cross-section structure picture of nitrocarburizing sample is as follows: Figure 4 shown; Figure 5 It is embodiment 3 surface layer object i...

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Abstract

The invention relates to a thermal treatment and plasma nitrocarburizing surface treatment process method for special wear-resistant die steel (HDCM) with ultrahigh heat conductivity for hot stamping a high strength steel plate / tube. The thermal treatment process comprises the following steps: quenching at 1050 DEG C-1000 DEG C and annealing twice at 560 DEG C-600 DEG C; the conditions of the surface treatment process are as follows: the voltage is 600V-850V, the atmosphere ratio is NH3:CO2=10: 1 to 16:1, the furnace pressure is 450Pa-700Pa, the nitriding temperature is 520 DEG C-550 DEG C, and the nitriding time is 8 hours-12 hours. In the aspect of overall performance, the performances of the special hot stamping die steel are as follows: the hardness is 51HRC-53HRC, and the notched bar impact strength Ak is about 170J-200J. After surface plasma nitridation, a compound layer is formed on the surface of the die. The white bright layer is 6mu m-17mu m thick, the Vickers Microhardness is 750HV300-750HV300, and the nitriding layer is 150mu m-260mu m. The hardness value of the die steel provided by the invention is higher than H13 in common thermal treatment, so that the wear resistance of the die can be improved, galling of the surface of the die can be effectively prevented, and the service life of the die can be greatly prolonged by virtue of plasma surface nitridation.

Description

technical field [0001] The invention relates to a process method for heat treatment and plasma nitrocarburizing surface treatment of ultra-high thermal conductivity wear-resistant die steel special for high-strength steel plate / pipe hot stamping, which is applied in the technical field of alloy steel heat treatment and surface treatment. Background technique [0002] Die steel is usually divided into three categories according to the object of mold use: cold work die steel, hot work die steel and plastic mold steel. Hot stamping die steel belongs to hot work die steel. With the rapid development of the automobile industry and the continuous improvement of the demand for lightweight automobiles, the hot stamping forming process is mainly used to obtain ultra-high-strength stamping parts. When obtaining ultra-high-strength steel, due to the extremely high forming force required by the cold stamping forming process, it is easy to cause mold damage, equipment vibration, and pro...

Claims

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Application Information

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IPC IPC(8): C23F17/00C21D1/18C23C8/36C23C8/32
Inventor 吴晓春李爽曹奇冯熙杨浩鹏张铮吴博雅
Owner SHANGHAI UNIV
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