Thermal treatment technology for special-shaped steel tube

A special-shaped steel pipe and process technology, applied in heat treatment furnaces, heat treatment equipment, metal material coating processes, etc., can solve the problems of low strength and toughness, and achieve the effects of good weldability, low thermal expansion coefficient and high precision

Inactive Publication Date: 2014-09-10
张家港市华尊宝特种材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is: to overcome the technical deficiency of low strength and toughness of special-shaped steel pipes in the prior art, and to provide a heat treatment process for special-shaped steel pipes, which can increase the yield strength of special-shaped steel pipes to 1100-1250 MPa, and the tensile strength Increase to 1200-1350MPa

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A heat treatment process for special-shaped steel pipes, said treatment process comprising the following steps:

[0021] (1) High-temperature tempering pretreatment before quenching and tempering heat treatment; the pretreatment temperature is 680°C, the holding time is 45min, and air-cooled to room temperature after the pretreatment is completed.

[0022] (2) After the tempering treatment is completed, the steel pipe is treated with a combination of ferritic chemical treatment and austenitic chemical treatment. Above the critical temperature, high-temperature chemical heat treatment of nitrocarburizing is carried out; at the same time, above the critical temperature Carry out high temperature chemical heat treatment of boronizing; then carry out austenitic aluminizing;

[0023] The heat treatment process of nitrocarburizing is as follows: the dried and purified ammonia gas is heated to 580°C through the spiral pipe, the nitrogen gas is heated to precipitate nitrogen io...

Embodiment 2

[0028] A heat treatment process for special-shaped steel pipes, said treatment process comprising the following steps:

[0029] (1) High-temperature tempering pretreatment is carried out before quenching and tempering heat treatment; the pretreatment temperature is 700°C, the holding time is 60min, and air-cooled to room temperature after the pretreatment is completed.

[0030] (2) After the tempering treatment is completed, the steel pipe is treated with a combination of ferritic chemical treatment and austenitic chemical treatment. Above the critical temperature, high-temperature chemical heat treatment of nitrocarburizing is carried out; at the same time, above the critical temperature Carry out high temperature chemical heat treatment of boronizing; then carry out austenitic aluminizing;

[0031] The heat treatment process of nitrocarburizing is as follows: the dried and purified ammonia gas is heated to 600°C through a spiral pipe, nitrogen is heated to precipitate nitrog...

Embodiment 3

[0036] A heat treatment process for special-shaped steel pipes, said treatment process comprising the following steps:

[0037] (1) High-temperature tempering pretreatment before quenching and tempering heat treatment; the pretreatment temperature is 730°C, the holding time is 75min, and air-cooled to room temperature after the pretreatment is completed.

[0038] (2) After the tempering treatment is completed, the steel pipe is treated with a combination of ferritic chemical treatment and austenitic chemical treatment. Above the critical temperature, high-temperature chemical heat treatment of nitrocarburizing is carried out; at the same time, above the critical temperature Carry out high temperature chemical heat treatment of boronizing; then carry out austenitic aluminizing;

[0039] The heat treatment process of nitrocarburizing is as follows: the dried and purified ammonia gas is heated to 630°C through the spiral pipe, the nitrogen gas is heated to precipitate nitrogen io...

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Abstract

The invention relates to the technical field of special-shaped steel tubes, and particularly relates to a thermal treatment technology for a special-shaped steel tube. The thermal treatment technology comprises the following steps: (1) carrying out high-temperature tempering treatment before quenched-tempered thermal treatment; (2) after the tempering treatment is completed, treating the steel tubes by adopting a method of combining chemical ferrite treatment and chemical austenite treatment; and (3) finally, conducting quenching and tempering, cooling the treated steel tubes into the range of 180-230DEG C, vacuumizing, conducting secondary quenching treatment, and insulating for 2.5-3h; heating again to 580-630DEG C, maintaining a vacuum state, conducting high-temperature tempering, insulating for 7-8h, then cooling to room temperature, thus completing the whole thermal treatment process. For the special-shaped steel tubes treated by the thermal treatment technology, the yielding strength is improved to 1100-1250MPa, the tensile strength is improved to 1200-1350MPa; the special-shaped steel tubes are long in anti-fatigue service life, wear-resistant, corrosion-resistant, low in thermal expansion coefficient, good in weldability, better in the whole straightness of the steel tubes, and low in residual stress; and the thermal treatment technology provided by the invention is green and environmentally friendly and low in cost.

Description

technical field [0001] The invention relates to the technical field of special-shaped steel pipes, in particular to a heat treatment process for special-shaped steel pipes. Background technique [0002] Special-shaped steel pipe is a long strip of steel with a hollow section, widely used in automobiles, trains, airplanes, ships and space launchers and other structural components, mechanical parts, petrochemical, geological drilling, textile machinery, radio communications, medical and health, Completion and other fields. The use of special-shaped steel pipes to manufacture ring parts can improve the utilization rate of materials, simplify the manufacturing process, and save materials and processing hours. [0003] In order to ensure the quality of the steel pipe and prolong the service life of the steel pipe, it is necessary to heat-treat the steel pipe. The traditional special-shaped steel pipe heat treatment process usually adopts normalizing heat treatment process, whic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23F17/00C21D9/08C23C8/32C23C8/70C23C10/20
Inventor 郭洪建杨日升
Owner 张家港市华尊宝特种材料科技有限公司
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