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Double temperature quenching and strong toughening treatment method for cold forging die

A treatment method and strengthening and toughening technology, which is applied in the direction of quenching agent, heat treatment equipment, manufacturing tools, etc., can solve the problems of poor toughness and high hardness, and achieve the effect of improving service life, high strength and improving toughness

Inactive Publication Date: 2005-08-17
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the defects of high hardness and poor toughness in conventional heat treatment of high-carbon, high-chromium steel and high-speed steel cold forging dies, the purpose of the present invention is to provide a cold forging die dual-temperature quenching strengthening and toughening treatment method for improving the toughness of cold forging dies

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The car planetary gear cold rolling die is made of Cr12MoV, and the conventional forging temperature is 850-1030°C. The cold forging die double-temperature quenching strengthening and toughening treatment method includes the following steps: 1) Forging: Cr12MoV heating temperature is 1100-1140°C, initial forging temperature is 1030-1060°C, adopts three-way forging deformation process, repeatedly upsetting-drawing 3 to 4 times, each upsetting compression ratio ≥ 50%, final forging temperature 850 ° C; slow cooling or direct annealing after forging; then processed into cold forging dies. Carbide unevenness level 2.

[0017] 2) High-temperature quenching: heat the cold forging die in vacuum, slowly heat to 850°C, keep warm for 40-50 minutes, continue heating to 1040-1060°C, keep warm, and then quench the cold forging die with oil; during the heating process, the vacuum degree is kept at 10.00~0.10Pa. After the cold forging die is filled with oil, immediately fill the col...

Embodiment 2

[0022] The car planetary gear cold rolling mold is made of 7Cr7Mo2V2Si. The cold forging die double-temperature quenching strengthening and toughening treatment method includes the following steps: 1) Forging: 7Cr7Mo2V2Si heating temperature is 1150°C, initial forging temperature is 1060°C, adopts three-way forging deformation process, repeatedly upsetting-extending 3 to 4 times , each upsetting compression ratio ≥ 50%, final forging temperature ≥ 850 ℃; slow cooling after forging and timely annealing treatment; and then processed into cold forging dies.

[0023] 2) High-temperature quenching: the cold forging mold is heated in vacuum, slowly heated to 860°C in vacuum, kept for 50-60 minutes, continued to be heated to 1130-1160°C, with a vacuum degree of 100.0-10.0Pa, and heat-preserved oil quenching. After entering the oil, fill it with the atmosphere immediately, so that the quenching oil surface has an atmospheric pressure. Start the oil stirring. The quenching time is 20...

Embodiment 3

[0028] The 63-28 / 02 bearing ring is made of high-speed steel W6Mo5Cr4V2 for cold-rolling and rough-rolling mandrel. 1) The rolled profile bar is directly processed into a cold forging die, and the unevenness of the original carbide is grade 3.

[0029] 2) High-temperature quenching process: vacuum heating of the cold forging mold, preheating to 850°C, heat preservation for 20 minutes, continued heating to 1220°C, vacuum degree 100.0-10.0Pa, heat preservation and oil quenching. After the cold forging die is filled with oil, start the quenching oil agitator. Quenching hardness HRC61~65 (average value HRC63.8). (Residual) austenite grain size 6-8. The first tempering temperature is 550°C,

[0030]3) Sub-high temperature fine-grain quenching: Slowly heat to 850°C, keep warm for 20 minutes, continue heating to 1160°C, keep warm, and then quench the cold forging mold with oil; after oiling the cold forging mold, start the quenching oil agitator. Quenching hardness HRC61~64.

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Abstract

The present invention relates to cold forging die toughening method and is especially one double temperature cold forging die-toughening quenching process. The double temperature cold forging die-toughening quenching process includes high temperature quenching and crystal fining quenching at relatively low temperature. In the high temperature quenching, the cold forging die is first vacuum heated, then oil quenched for 10-20 min while air is filled and tempered at 250-550 deg.c. In the subsequent crystal fining quenching at relatively low temperature, the cold forging die is first vacuum heated slowly to 850 deg.c, maintained for 20-60 min, further heated to 970-1160 deg.c and maintained, then oil quenched for 10-20 min while air is filled, and finally tempered at 450-550 deg.c for three or four times. The said process can raise the toughness and increase the service life of cold forging die obviously.

Description

technical field [0001] The invention relates to a method for improving the toughness of a cold forging die. Background technique [0002] Compared with ordinary forging dies, cold forging dies require higher processing precision. In order to ensure the shape and dimensional accuracy of forgings, the fillet radius and cantilever height on the cold forging die cavity are basically designed according to the finished product size, which is prone to stress concentration. During use, the mold will bear severe impact loads, and the surface of the cavity must bear high tensile and compressive stresses, cracking and chipping are common, serious wear, and low service life; therefore, cold forging die materials are required to have high Strength, toughness and wear resistance. [0003] Cold forging dies for mass production are often made of high-carbon high-chromium alloy steel, high-speed steel or matrix steel. High-carbon high-chromium steel (such as Cr12MoV) is a ledeburite steel,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/00C21D1/18C21D1/58C21D1/773C21D6/00C21D7/13
Inventor 华林余际星赵玉民贾耿伟
Owner WUHAN UNIV OF TECH
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