CN102528193A - A brazing process for welding copper and stainless steel - Google Patents

Abstract

The invention relates to a brazing process for welding copper and stainless steel, which is characterized by comprising the following steps of: 1) pre-treatment of welding; 2) assembling a joint; 3) adding brazing filler metal and brazing flux; 4) welding; 5) and (5) post-welding treatment. The brazing process of the invention utilizes the copper-based brazing filler metal to replace the silver-based brazing filler metal, thus greatly reducing the preparation cost and greatly saving the noble metal resources; welding is carried out in the air without protective gas, so that the consumption cost of nitrogen, argon and the like is reduced; the induction heating welding technology is applied to replace the welding technology in a protective gas furnace and the welding technology in a vacuum furnace, and the electric energy is saved. The brazing process method is reliable, short in production time, high in production qualification rate, energy-saving and suitable for batch production.

Description

A brazing process for welding copper and stainless steel

technical field

The invention relates to a welding technology used for dissimilar metals, in particular to a welding process for copper and stainless steel dissimilar metal inlet and outlet water pipe joints.

Background technique

Two different metal inlet and outlet pipe joints, copper and stainless steel, are important components in the radiator system of automobile water tanks and the radiator system of household air conditioners, and their quality has an important impact on the normal operation of the radiator system.

The two metal materials, copper and stainless steel, are obviously different in physical properties and chemical composition. The melting point and thermal conductivity coefficient of the two metals are quite different, which has always brought great benefits to the manufacture of such inlet and outlet pipe joints. process difficulty.

Contents of the invention

The present invention designs a brazing process for welding copper and stainless steel, the purpose of which is to solve the complex welding process of the joints of stainless steel and copper dissimilar metals in the radiator system of automobiles and household air-conditioning radiator systems. To solve the problems of high cost and high energy consumption, it provides a copper and stainless steel dissimilar metal brazing process that meets the international brazing standards, meets the quality design requirements for the inlet and outlet water pipe joints of automobile cooling systems and household air-conditioning systems, has reliable methods, and has a high welding yield.

In order to achieve the above object, the present invention adopts the following scheme:

A brazing process for welding copper and stainless steel is characterized in that it comprises the following steps:

1) Pre-welding treatment;

2) Joint assembly;

3) Add solder and flux;

4) Welding;

5) Post-welding treatment.

Step 1) The pre-welding treatment is to clean the parts of the water pipe joints that need to be welded. First, put the parts of the water pipe joints that need to be welded into a cleaning solution with a metal surface degreasing agent, and heat them for ultrasonic cleaning. Then rinse with clean water, take out and dry for later use.

Step 2) The joint assembly is to put the annular copper-based solder and stainless steel pipe fittings on the outside of the copper pipe fittings in sequence, and the gap between the copper pipe fittings and the stainless steel pipe fittings is 0.05mm-0.20mm; to ensure the contact surface of the copper fittings and the stainless steel fittings The flatness makes the contact part seamless when the weld seam is assembled with the annular solder.

Step 3) The adding of solder and flux is to apply flux evenly on the welds of copper pipe fittings and stainless steel pipe fittings, and the amount of flux is not more than 1 g/piece.

Step 4) The welding includes the following steps:

a) Put the inlet and outlet water pipe joints filled with brazing material and brazing flux into the special brazing tooling for this joint, and clamp the workpiece;

b) Put the inlet and outlet pipe joints filled with solder and flux into the heating area of the induction heating equipment together with the tooling, and ensure that the welding position is in the center of the welding area, then heat and keep warm;

c) After the heat preservation is over, stop heating and let the weldment cool down naturally.

The heating and heat preservation process in the step b) is as follows: linearly increase the temperature of the induction heating equipment, so that the temperature of the welding part rises from room temperature to 890 ° C at a uniform speed, and the time is 15s-30s, adjust the frequency of induction heating, so that the temperature of the welding part rises slowly to 910°C-954°C, the time is 3s-5s, and then keep warm for 2s-3s.

Step 5) The post-welding treatment is firstly to detect the quality of copper and stainless steel inlet and outlet pipe joints with an ultrasonic automatic detection device; and then to clean the finished product after welding.

The cleaning of the finished product after welding is to put the welded water inlet and outlet pipe joint parts into the special cleaning solution for copper and stainless steel, soak for 15min-30min, then take it out and rinse it with clean water, and then put it into the special passivation solution for copper and stainless steel Perform passivation treatment, soak for 10min-30min, take it out, rinse it with clean water, and dry the package.

Step 1) The ultrasonic cleaning time is 30min-60min, and the drying temperature is 35°C-70°C.

The brazing process used for welding copper to stainless steel. Has the following beneficial effects:

(1) The brazing process of the present invention uses copper-based solder to replace silver-based solder, which greatly reduces the preparation cost and saves a lot of precious metal resources.

(2) The brazing process of the present invention implements welding in the air without protective gas, reducing the consumption cost of nitrogen, argon and the like.

(3) The brazing process of the present invention uses the induction heating welding technology, which replaces the welding in the shielding gas furnace and the welding in the vacuum furnace, saving more than 60% of electric energy.

(4) The brazing process of the present invention has the characteristics of reliable method, short production time, high production qualification rate, energy saving, cost saving, etc., and is easily applicable to mass production.

(5) After the brazing process of the present invention, the residue after welding is easy to clean, ensuring the appearance of the weldment.

Detailed ways

Below in conjunction with specific embodiment, the present invention will be further described:

Example 1

The brazing process for welding copper to stainless steel involves the following steps:

1) Pre-welding treatment: To clean the water pipe joint parts that need to be welded, first put the water pipe joint parts that need to be welded into the cleaning solution with metal surface degreasing agent, heat for ultrasonic cleaning, and then use clean water Rinse and remove to dry. The ultrasonic cleaning time is 30 minutes, and the drying temperature is 40°C.

2) Joint assembly: Put the ring-shaped copper-based solder and stainless steel pipe fittings on the outside of the copper pipe fittings in turn, the gap between the copper pipe fittings and the stainless steel pipe fittings is 0.08mm; ensure the flatness of the contact surface of the copper fittings and stainless steel fittings so that the weld seam There is no gap in the contact part when it is assembled with the ring solder.

3) Add solder and brazing flux; apply flux evenly on the welds of copper pipe fittings and stainless steel pipe fittings, and the flux amount is 0.5 g/piece.

4) Welding: a) Put the inlet and outlet pipe joints with brazing material and flux into the special brazing tool for the joint, and clamp the workpiece; b) Put the inlet and outlet pipe joints with brazing material and flux into the induction joint together with the tooling In the heating area of the heating equipment, ensure that the welding position is in the center of the welding area, then heat and keep warm; make the induction heating equipment rise in temperature linearly, so that the temperature of the welding part rises from room temperature to 890 ° C at a uniform speed, and the time is: 15s. Adjust the induction heating frequency to make The temperature of the welding part is slowly raised to 910°C for 3s-5s, and then kept warm for 2s-3s.

c) After the heat preservation is over, stop heating and let the weldment cool down naturally.

5) Post-welding treatment: First, use an ultrasonic automatic detection device to detect the quality of copper and stainless steel inlet and outlet pipe joints; then clean the finished product after welding, and put the welded inlet and outlet pipe joint parts into copper and stainless steel special cleaning solution , soak for 15 minutes, then take it out and rinse it with clean water, then put it into the special passivation solution for copper and stainless steel for passivation treatment, soak it for 10 minutes, take it out, rinse it with clean water, and dry the package.

Example 2

The brazing process for welding copper to stainless steel involves the following steps:

1) Pre-welding treatment: To clean the water pipe joint parts that need to be welded, first put the water pipe joint parts that need to be welded into the cleaning solution with metal surface degreasing agent, heat for ultrasonic cleaning, and then use clean water Rinse and remove to dry. The ultrasonic cleaning time is 60 minutes, and the drying temperature is 60°C.

2) Joint assembly: put the ring-shaped copper-based solder and stainless steel pipe fittings on the outside of the copper pipe fittings in turn, the gap between the copper pipe fittings and the stainless steel pipe fittings is 0.18mm; ensure the flatness of the contact surface of the copper fittings and stainless steel fittings so that the weld seam There is no gap in the contact part when it is assembled with the ring solder.

3) Add brazing filler metal and brazing flux; evenly smear flux on the welding seam of copper pipe fittings and stainless steel pipe fittings, and the flux amount is 1 g/piece.

4) Welding: a) Put the inlet and outlet pipe joints with brazing material and flux into the special brazing tool for the joint, and clamp the workpiece; b) Put the inlet and outlet pipe joints with brazing material and flux into the induction joint together with the tooling In the heating area of the heating equipment, ensure that the welding position is in the center of the welding area, then heat and keep warm; make the induction heating equipment rise in temperature linearly, so that the temperature of the welding part rises from room temperature to 890 ° C at a uniform speed, and the time is: 30s. Adjust the induction heating frequency to make The temperature of the welding part is slowly raised to 954°C for 3s-5s, and then kept for 2s-3s.

c) After the heat preservation is over, stop heating and let the weldment cool down naturally.

5) Post-welding treatment: First, use an ultrasonic automatic detection device to detect the quality of copper and stainless steel inlet and outlet pipe joints; then clean the finished product after welding, and put the welded inlet and outlet pipe joint parts into copper and stainless steel special cleaning solution , soak for 30 minutes, then take it out and rinse it with clean water, then put it into the special passivation solution for copper and stainless steel for passivation treatment, soak it for 15 minutes, take it out, rinse it with clean water, and dry the package.

Above, the present invention has been exemplarily described in conjunction with specific embodiments. Obviously, the realization of the present invention is not limited by the above-mentioned manner, as long as various improvements of the method concept and technical solutions of the present invention are adopted, or the present invention is converted without improvement. The ideas and technical solutions of the invention are directly applied to other occasions, all within the protection scope of the present invention.

Claims (9)

1. a brazing process for copper and stainless steel welding, is characterized in that comprising the following steps: 1) Pre-welding treatment; 2) Joint assembly; 3) Add solder and flux; 4) Welding; 5) Post-welding treatment. 2. The brazing process for welding copper and stainless steel according to claim 1, characterized in that: Step 1) The pre-welding treatment is to clean the parts of the water pipe joints that need to be welded, and firstly clean the parts that need to be welded Put the parts of the water pipe joint into the cleaning solution with metal surface degreasing agent, heat it for ultrasonic cleaning, then rinse it with clean water, take it out and dry it for later use. 3. The brazing process for welding copper and stainless steel according to claim 1 or 2, characterized in that: step 2) the joint assembly is to put the ring-shaped copper-based solder and stainless steel pipe fittings on the copper pipe fittings in sequence On the outside, the gap between copper pipe fittings and stainless steel pipe fittings is 0.05mm-0.20mm; ensure the flatness of the contact surface of copper parts and stainless steel parts so that there is no gap in the contact part when the welding seam is assembled with the ring solder. 4. The brazing process for welding copper and stainless steel according to claim 3, characterized in that: step 3) said adding brazing filler metal and flux is to apply flux evenly at the welding seam of copper pipe fittings and stainless steel pipe fittings , the amount of solder is not more than 1 g/piece. 5. The brazing process for welding copper and stainless steel according to claim 4, characterized in that: step 4) said welding includes the following steps: a) Put the inlet and outlet water pipe joints filled with brazing material and brazing flux into the special brazing tooling for this joint, and clamp the workpiece; b) Put the inlet and outlet pipe joints filled with solder and flux into the heating area of the induction heating equipment together with the tooling, and ensure that the welding position is in the center of the welding area, then heat and keep warm; c) After the heat preservation is over, stop heating and let the weldment cool down naturally. 6. The brazing process for copper and stainless steel welding according to claim 5, characterized in that the heating and heat preservation process in the step b) is: the induction heating equipment is linearly heated, and the temperature of the welding part is uniformly increased from room temperature to 890°C, the time is 15s-30s, adjust the induction heating frequency, so that the temperature of the welding part rises slowly to 910°C-954°C, the time is 3s-5s, and then keep warm for 2s-3s. 7. The brazing process for welding copper and stainless steel according to claim 3, 4 or 5, characterized in that: step 5) the post-welding treatment is firstly, using an ultrasonic automatic detection device to inspect the copper and stainless steel inlet and outlet pipe joints The quality is inspected; then the finished product after welding is cleaned. 8. The brazing process for welding copper and stainless steel according to claim 7, characterized in that: the cleaning of the finished product after welding is to put the welded inlet and outlet pipe joint parts into the special cleaning solution for copper and stainless steel , soak for 15min-30min, then take it out and rinse it with clean water, then put it into the special passivation solution for copper and stainless steel for passivation treatment, soak it for 10min-30min, take it out, rinse it with clean water, and dry the package. 9. The brazing process for welding copper and stainless steel according to any one of claims 1-8, characterized in that: step 1) the ultrasonic cleaning time is 30min-60min, and the drying temperature is 35°C -70°C.