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Elbow classification and precautions when pushing the elbow during welding

Update:30 Aug 2019
Summary:

The elbow is one of the pipe fittings, and the purpose […]

The elbow is one of the pipe fittings, and the purpose of the elbow is to connect the pipe into the parts of the pipe. According to the connection method, it can be divided into four types: socket type pipe fittings, threaded pipe fittings, elbow fittings and welded fittings.

In the commonly used elbow specifications, it has been replaced by a hot push elbow, but in some models, the elbow is too thin or too thick due to the small amount of production.

Elbow products have special requirements to use the stamping production process. In the process of forming the stamping elbow, the caliber is the same as the diameter of the produced elbow, and the press is directly pressed into the mold.

The punching elbow is divided into cold stamping and hot stamping. The material of the stamping elbow is selected and manufactured. The manufacturing process of the punching elbow is not as good as the elbow. The quality is not as good as the former. The outer elbow is stretched during the forming of the punching elbow. In the state, there is no excess metal in other parts to compensate, so the wall thickness at the outer arc is about 10% thinner.

However, due to its application to unit manufacturing and low cost, the stamping elbow manufacturing process is suitable for the production of high-pressure thick-wall stamping elbows in small batches.

The extrusion elbow uses a special elbow forming machine to put the tube blank into the mold. After the upper and lower molds are closed, the tube blank is moved along the gap between the inner and outer molds to complete the forming process. . The elbow manufactured by the inner and outer mold cold extrusion process has beautiful appearance, uniform wall thickness and small dimensional deviation, so the cold extrusion manufacturing process is suitable for the manufacture of thin-walled stainless steel elbows, and the precision of the inner and outer molds used in this process High; the wall thickness deviation requirements of the tube blank are also more demanding.

What are the precautions when pushing the elbow during welding?

1. The elbow is very hardened after welding and cracks easily occur. If the same type of punching elbow is selected for welding, the push elbow must be preheated above 300 °C and slow-cooled at 700 °C after welding. If the weldment is not possible for post weld heat treatment. Then you should choose a stamped elbow electrode.

2. In order to avoid the erosion of the elbow due to heating, the welding current is not suitable for selection too much, it is 20% less than the carbon steel electrode, the arc should not be too long, the layer is fast cold, and the narrow bead is should

The push elbow is the push-type elbow. Nowadays, the most important one of the elbow forming production technology is the push-made elbow, which is the push bend. The production of the head is fast, and then the production of the elbow can be produced in batches. The quality of the elbow is good, and the forming technology of the elbow is the most important molding manufacturing of the elbow. technology.