Analysis of Welding and Silver Brazing in Valves

- May 20, 2018-

Welding and silver brazing

It is important to remember what the recommended valve is for and analyze the applied environment to determine which valve is best suited for installation. Before installing the correct valve, please read the installation guide to prevent damage to the valve and to ensure full performance of the valve.

1. Cut the pipe in the vertical direction, trim and remove burrs, and measure the pipe diameter.

2. Use a gauze or wire brush to clear the pipe and cutting area so that the metal surface shines. It is recommended not to use steel wool.

3. Apply flux to the outside of the pipe and inside the welding cover. The flux must completely cover the welding surface. Please use flux sparingly.

4. Make sure the valve is open. Heat the pipe first. Pass heat as much as possible from the pipe to the valve. Avoid prolonging the heating time of the valve itself.

5. Silver Brazing Method: Assemble parts that require brazing. If the flux-applied component is allowed to stand upright, the moisture in the flux will evaporate, and the dried flux can easily fall off, causing the exposed metal surface to be easily oxidized. When performing the connection assembly, insert the pipe into the socket until it stops. The assembly is to ensure a stable support so that it can remain in a straight position throughout the brazing operation.

NOTE: For valves with a nominal size of 1 inch or larger, it is difficult to heat the connecting parts to the required temperature all at once. In order to maintain a normal temperature over a large area, two welding torches are usually required. It is recommended to properly warm up the entire area of the jacket. It is recommended that the acetylene flame be used to heat the connecting parts. First heat the pipe 1 inch from the valve. Then alternately flame the pipe around the pipe a short distance up and down. Rotate the pipe at an appropriate angle to avoid burning through the pipe. The flame must move continuously and it is not allowed to stay at a certain point.

The sleeve base of the valve is baked with a flame. The heating should be uniform, and the flame baking of the valves and pipes with flames should continue until the flux on the valve no longer makes a sound. Do not overheat the valve.

When the flux becomes liquid and assumes a translucent state on the pipe and valve, the flame is started to be baked along the axis of the connecting member, so as to maintain the heat of the connecting member, particularly the seat portion of the valve sleeve.

6. Use the right amount of solder: If you use wire solder, use 3/4 inch of solder for valves with a nominal 3/4 inch diameter. If too much solder is used, some solder may flow through the pipe blockage and plug the seal area. When installing the connection parts, you can see that the solder and brazing alloy continue to flow

7. Silver Brazing Method: Point the wire or rod to the valve

The pipe fittings in the door. When the welding rod or welding wire enters the joint, the flame is to be removed from it. When the alloy flows into the joint, move the flame back and forth. After reaching the proper temperature, the alloy will quickly and easily flow into the space between the pipe casing and the valve casing. After the joint is filled, you will see the edges of the welded alloy.

8. When the solder is in a viscous state, use a brush to remove the excess solder. After the solder cools, place a fillet around the valve's port.