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Heat shock resistant graphite and metal brazing method

A brazing method and metal technology, applied in the direction of metal processing equipment, welding equipment, manufacturing tools, etc., can solve the problem of thermal shock resistance without joints, and achieve the effect of reducing residual thermal stress

Pending Publication Date: 2022-03-15
AVIC BEIJING INST OF AERONAUTICAL MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] These two patents target SiO 2f / SiO 2 Heterogeneous bonding of ceramic composites to metals in SiO 2f / SiO 2 The surface of the composite material is grooved to realize the brazing connection of heterogeneous materials with large differences, but there is no assessment and evaluation of the thermal shock resistance of the joint

Method used

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  • Heat shock resistant graphite and metal brazing method
  • Heat shock resistant graphite and metal brazing method
  • Heat shock resistant graphite and metal brazing method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] On the welding surface of the graphite base material to be welded with a diameter of 60mm, press figure 1 The machined annular groove shown is the center position of the groove is R7.5mm, R12.5mm, R17.5mm, R22.5mm, R27.5mm in the radial direction, the width is 1mm, and the depth is 0.5mm;

[0026] When brazing assembly, first fill the groove with AgCuTi metal solder powder, scrape it flat with a blade, and then place a 50-micron AgCuTi solder foil strip between the graphite and pure iron, and the assembled module to be brazed Such as figure 2 shown.

[0027] Put the assembled graphite and pure iron samples into a vacuum brazing furnace for vacuum brazing. The brazing specification is 870°C, the holding time is 10min, and the temperature is lowered to 450°C at a cooling rate lower than 5°C / min. , and then cooled to room temperature with the furnace.

[0028] Put the obtained joint into the air furnace at 450°C for 10 minutes, take it out and put it directly into cold...

Embodiment 2

[0030] On the welding surface of the graphite base material to be welded with a diameter of 60mm, press figure 1 The machined annular groove shown is the center position of the groove is R7.5mm, R12.5mm, R17.5mm, R22.5mm, R27.5mm in the radial direction, the width is 1mm, and the depth is 0.5mm;

[0031] When brazing assembly, first fill the groove with AgCuInTi metal solder powder, scrape it flat with a blade, and then place a 50-micron AgCuInTi solder foil strip between the graphite and pure iron, and the assembled module to be brazed Such as figure 2 shown.

[0032] Put the assembled graphite and pure iron samples into a vacuum brazing furnace for vacuum brazing. The brazing specification is 800°C, the holding time is 10min, and the temperature is lowered to 450°C at a cooling rate lower than 5°C / min. , and then cooled to room temperature with the furnace.

[0033] Put the obtained joint into the air furnace at 450°C for 10 minutes, take it out and put it directly into ...

Embodiment 3

[0035] On the welding surface of the graphite base material to be welded with a diameter of 60mm, press figure 1 The machined annular groove shown is the center position of the groove is R7.5mm, R12.5mm, R17.5mm, R22.5mm, R27.5mm in the radial direction, the width is 1mm, and the depth is 0.5mm;

[0036]When brazing assembly, first fill the groove with AgCuTi metal solder powder, scrape it flat with a blade, then put the graphite filled with metal solder powder into a vacuum brazing furnace, raise the temperature to 870°C and keep it for 10 minutes, so that The metal powder is melted, and the temperature is lowered to 450°C at a cooling rate not greater than 5°C / min, and then cooled to room temperature with the furnace;

[0037] Take out the pre-brazed graphite, fill the groove with AgCuTi metal solder powder and scrape it flat with a blade, then place a 50-micron AgCuTi solder foil strip with a thickness of 50 microns between the graphite and the pure iron, and the finished a...

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Abstract

The invention discloses a heat shock resistant graphite and metal brazing method, and belongs to the technical field of ceramic / metal dissimilar material connection. The method comprises the steps that a groove is machined in the welding surface of to-be-brazed graphite, the groove is filled with metal brazing filler metal, the welding surface of the graphite is covered with a foil strip made of the metal brazing filler metal, the foil strip is covered with the welding surface of to-be-brazed metal, a to-be-brazed module is formed, the to-be-brazed module is placed in a vacuum brazing furnace to be subjected to vacuum brazing, and the to-be-brazed graphite is obtained. The brazing temperature ranges from 780 DEG C to 900 DEG C, after heat preservation is conducted for 5 min to 20 min, the temperature is reduced to 450 DEG C at the cooling rate lower than 5 DEG C / min, and then the alloy is cooled to the room temperature along with a furnace. According to the invention, the residual thermal stress formed after graphite / electromagnetic pure iron heterogeneous brazing is reduced, the reliability of the joint is improved, and the joint can bear thermal shock of 450 DEG C to cold water (20 DEG C) for not less than 10 times.

Description

technical field [0001] The invention relates to a thermal shock-resistant graphite-metal brazing method, which belongs to the technical field of ceramic / metal dissimilar material connection. Background technique [0002] Graphite has excellent properties such as high melting point, low density, low thermal expansion coefficient, corrosion resistance and thermal fatigue resistance, and is widely used in aerospace, energy, power electronics and other fields. However, graphite has poor mechanical properties and often needs to be connected with metal materials to achieve complementary performance. Electromagnetic pure iron DT4C is a soft magnetic material with a carbon content of less than 0.04%. It has high saturation magnetization and is often used as a magnetic core material. [0003] However, the thermal expansion coefficients of the two materials are quite different. There will be a large residual thermal stress in the brazed joint of the two materials, which will lead to ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K1/008B23K1/20B23K1/19
CPCB23K1/008B23K1/20B23K1/19
Inventor 李文文陈波裴冲冯洪亮熊华平
Owner AVIC BEIJING INST OF AERONAUTICAL MATERIALS
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