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A method for softening and annealing crnimo quenched and tempered steel using a gas annealing furnace

A softening annealing and annealing furnace technology, applied in the field of softening annealing of CrNiMo quenched and tempered steel, can solve the problems of inability to meet user requirements and high hardness

Active Publication Date: 2018-09-14
SHANXI TAIGANG STAINLESS STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] CrNiMo quenched and tempered steel is forged by a fast forging machine. After forging, a single-step stress relief annealing process in a gas annealing furnace is used. The existing stress relief annealing process has high hardness after annealing and cannot meet user requirements.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0008] 1. Put 4 pieces of 30CrNiMo8 quenched and tempered steel forging round into a bundle into the gas annealing furnace, and the initial temperature of the annealing furnace is 100°C;

[0009] 2. The heating rate is 100°C per hour, and the temperature is kept at 690°C for 6 hours;

[0010] 3. Cool down to 400°C at 30°C / h and keep warm for 10 hours;

[0011] 4. Cut off the power supply, and after the furnace is cooled to 300°C, move the forging circle out of the annealing furnace, and cool it naturally in the air.

[0012] In the softening annealing method of CrNiMo quenched and tempered steel in this embodiment, adding low-temperature heat preservation steps instead of single-step stress-relief annealing, the hardness is significantly reduced after annealing, which has a softening effect and meets the user's requirements.

Embodiment 2

[0014] 1. Put 4 pieces of 30CrNiMo8 quenched and tempered steel forging round into a bundle into the gas annealing furnace, and the initial temperature of the annealing furnace is 100°C;

[0015] 2. The heating rate is 100°C per hour, and the temperature is kept at 690°C for 6 hours;

[0016] 3. Cool down to 400°C at 30°C / h and keep warm for 10 hours;

[0017] 4. Cut off the power supply, after the furnace cools to 300°C, turn on the power supply again, the heating rate is 100°C per hour, and keep warm for 4 hours after the temperature rises to 400°C;

[0018] 5. Cut off the power supply, and after the furnace is cooled to 300°C, move the forging circle out of the annealing furnace, and cool it naturally in the air.

[0019] The softening annealing method of CrNiMo quenched and tempered steel in this example adopts adding low-temperature heat preservation steps instead of single-step stress relief annealing, and then heats up to 400°C again and then stress relief annealing ag...

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PUM

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Abstract

The invention relates to the technical field of CrNiMo hardened and tempered steel softening and annealing, in particular to a method for softening and annealing CrNiMo hardened and tempered steel through a gas annealing furnace. According to the method for softening and annealing the CrNiMo hardened and tempered steel through the gas annealing furnace, the temperature of the CrNiMo hardened and tempered steel in the gas annealing furnace is increased to 690+ / -10 DEG C, heat preservation is conducted for 6 h or longer, then the temperature is reduced to 400+ / -10 DEG C at the rate lower than or equal to 30 DEG C / h, heat preservation is conducted for 10 h, then, furnace cooling is conducted to 300+ / -10 DEG C, and air cooling is conducted to the room temperature later. Softening and annealing of the CrNiMo hardened and tempered steel are achieved by consuming little energy.

Description

technical field [0001] The invention relates to the technical field of softening and annealing of CrNiMo quenched and tempered steel, in particular to a method for softening and annealing of CrNiMo quenched and tempered steel using a gas annealing furnace. Background technique [0002] CrNiMo quenched and tempered steel is forged by a fast forging machine. After forging, a single-step stress relief annealing process in a gas annealing furnace is used. The existing stress relief annealing process has high hardness after annealing, which cannot meet user requirements. Contents of the invention [0003] The technical problem to be solved by the invention is: how to significantly reduce the hardness of CrNiMo quenched and tempered steel through primary annealing, avoiding secondary annealing. [0004] The technical solution adopted in the present invention is: a method of softening and annealing CrNiMo quenched and tempered steel using a gas annealing furnace, raising the CrNi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/32C21D6/00
CPCC21D1/32C21D6/004
Inventor 乔小梅许立伟姚宁郑壮
Owner SHANXI TAIGANG STAINLESS STEEL CO LTD