CN-117488218-B - Heat treatment method of low-hardness sealing copper pad

CN117488218BCN 117488218 BCN117488218 BCN 117488218BCN-117488218-B

Abstract

The invention relates to a heat treatment method of a low-hardness sealing copper pad, which takes a bar as a processing base material, is processed into the copper pad according to a designed size, avoids the hardness change of the copper pad caused by secondary hardening after heat treatment, carries out primary heat treatment after pretreatment on the processed copper pad, and ensures that the heat preservation temperature of the heat treatment is determined by the cold deformation rate of the copper pad raw material, the higher the deformation rate is, (the recovery recrystallization) the higher the heat preservation temperature is, and the lower the original size of the material for processing the copper pad is, the higher the heat preservation temperature is selected. When the target hardness is not satisfied, a first cold treatment or a second heat treatment is used. The invention can control the hardness to 30 HBW-40 HBW, and more accords with the design requirement of a contact type mechanical seal form.

Inventors

YUAN YUKUN
ZHU WEIQIANG
LI YAHONG
ZHANG ZHIZHENG
ZHENG SHULI

Assignees

西安长峰机电研究所

Dates

Publication Date: 20260508
Application Date: 20231017

Claims (1)

1. A heat treatment method of a low-hardness sealing copper pad is characterized by adopting a supplementary heat treatment process of secondary annealing and cold treatment, comprising the following steps: the bar is used as a processing base material, and is machined into a copper pad according to the designed size, so that the hardness change of the copper pad caused by secondary hardening after heat treatment is avoided; after pretreatment is carried out on the processed copper pad, the copper pad is placed in a vacuum furnace and vacuumized to 1.33-13.3 Pa; The first heat treatment, namely heating to 420-480 ℃ and preserving heat for 20-30 min; Slowly heating to 630-680 ℃, cooling to below 100 ℃ in a power-off furnace without heat preservation, and discharging for air cooling; when the hardness of the primary detection meets the target hardness, the heat treatment of the sealing copper gasket is completed; Performing a second heat treatment when the hardness of the primary test does not satisfy the target hardness: When the hardness of the initial detection is lower than the target hardness by 0-5, adopting cold treatment at-70 ℃ to-90 ℃, preserving heat by 150 min-180 min, and performing air cooling; When the hardness of the primary detection is higher than the target hardness by 0-8, repeating the first heat treatment, and adjusting the process parameters to the upper limit for 2 times of heat treatment, namely heating to 480 ℃ and preserving heat for 30min, heating to 680 ℃ at 1.2 ℃ per min, not preserving heat, cooling to below 100 ℃ by a power-off furnace, and discharging for air cooling, wherein the slow heating rate is 0.8-1.2 ℃ per min; The pretreatment is to clean a sealing copper pad by adopting ethyl acetate; After the copper pad is inspected to be qualified, the anti-rust oiled paper is singly packaged, and is put into a packaging box, and 99.99% of nitrogen is filled into the box; The heat preservation temperature of the first heat treatment is in direct proportion to the cold deformation rate of the copper pad raw material; the heat preservation temperature of the first heat treatment is inversely proportional to the original size of the material for processing the copper pad.

Description

Heat treatment method of low-hardness sealing copper pad Technical Field The invention belongs to a heat treatment processing technology method, and relates to a heat treatment method of a low-hardness sealing copper pad, which ensures that the hardness of the heat-treated sealing copper pad is in the range of 30 HBW-40 HBW. Background The red copper has a purple oxide film on the surface, which is named as a face-centered cubic structure, has good heat conduction, electric conductivity, weldability, ductility and corrosion resistance, and is widely applied to industries such as electronics, aerospace shipbuilding, mechanical equipment, dies and the like. Particularly, the requirements of the aerospace industry on red copper sealing copper gaskets are larger and larger, and the contact type mechanical sealing form has stronger inclusion for complex working conditions of the aviation aircraft. The sealing is realized by mainly matching the end face of the joint with higher hardness and the red copper gasket with lower hardness, and the sealing performance is realized by mainly compressing and deforming the red copper gasket so as to fill the gap of the end face. The copper pad has too high hardness to cause insufficient deformation, too low hardness to cause material disintegration in the deformation process, and damage, and can not meet the sealing requirement. Therefore, the hardness of the red copper gasket directly affects the sealing performance, and the red copper sealing performance is also an important research content in the field. Because the emphasis of each industry is different, the existing process method cannot meet the performance required under different conditions, and the state (deformation) of the raw material also has an influence on the performance of the material after heat treatment, so that the difficulty is increased for the process test. In particular, there is no document about control of low hardness (30 to 40 HBW) after red copper annealing. In order to meet the design requirement of the product, the hardness of the annealed material is in the safe use range of the product. Disclosure of Invention Technical problem to be solved In order to avoid the defects of the prior art, the invention provides a heat treatment method of a low-hardness sealing copper pad, which ensures that the hardness of the heat-treated sealing copper pad is in the range of 30 HBW-40 HBW, solves the problem that the hardness of a conventional heat-treated gasket cannot meet the sealing requirement, and improves the heat treatment qualification rate of the sealing copper pad. Technical proposal A heat treatment method of a low-hardness sealing copper pad is characterized by adopting a supplementary heat treatment process of secondary annealing and cold treatment, comprising the following steps: the bar is used as a processing base material, and is machined into a copper pad according to the designed size, so that the hardness change of the copper pad caused by secondary hardening after heat treatment is avoided; Pretreating the processed copper pad, and vacuumizing to 1.33-13.3 Pa after the copper pad is placed in a vacuum furnace; The first heat treatment, namely heating to 420-480 ℃ and preserving heat for 20-30 min; the heat preservation temperature is determined by the cold deformation rate of the copper pad raw material, and the higher the deformation rate is, the higher the heat preservation temperature is (the recovery recrystallization) is, and the lower the original size of the copper pad processing material is, the higher the heat preservation temperature is selected. Slowly heating to 630-680 ℃, cooling to below 100 ℃ in a power-off furnace without heat preservation, and discharging for air cooling; when the hardness of the primary detection meets the target hardness, the heat treatment of the sealing copper gasket is completed; Performing a second heat treatment when the hardness of the primary test does not satisfy the target hardness: when the hardness of the initial detection is lower than the target hardness (0-5), adopting cold treatment at-70 ℃ to-90 ℃, preserving heat for 150-180 min, and air cooling; and when the hardness of the primary detection is higher than the target hardness (0-8), repeating the first heat treatment, adjusting the technological parameters to the upper limit, and performing heat treatment for 2 times, namely heating to 480 ℃, preserving heat for 30min, heating to 680 ℃ at 1.2 ℃ per min, not preserving heat, powering off the furnace, cooling to below 100 ℃, and discharging for air cooling. The slow heating rate is 0.8-1.2 ℃ per minute. The machining adopts turning. The pretreatment is to clean the sealing copper pad by adopting ethyl acetate. And (3) after the copper pad is inspected to be qualified, independently packaging the copper pad with the antirust oilpaper, putting the copper pad into a packaging box, and filling 99.99% nitrogen into the box. The heat preser