P9 elbow

During the processing of P9 elbow, in the pipeline system, the intermediate frequency elbow can change the direction of the pipeline to a certain extent during operation. According to its angle during operation, P9 elbow can be divided into three common types: 45 °, 90 ° and 180 °

P9 elbow can be determined according to the engineering needs, including other abnormal angle elbows such as 60 ° elbow. During the manufacturing process, the elbow materials can be determined as alloy steel, castable iron, carbon steel, cast iron, stainless steel, non-ferrous metals and plastics

P9 bends will be directly welded to the pipe during operation. According to the production process, they can be classified into welded bends, punched bends, and cast bends. A common pipe fitting used for connection in pipe installation, which is used for connection at pipe bends

The stress analysis during the processing of P9 elbow, during the bending process, the pipe wall at the back of the bending will be stretched and thinned, and the bending concave will be squeezed and thickened when in use. In general, the pipe will be stretched because the compressive strength of the metal material is superior to the tensile strength when in use; The pipe bending is stressed in the concave convex direction, and the side is not stressed, and the pipe section becomes elliptical

Protective measures for processing quality of P9 elbow

1. The elbow adopts positive tolerance. When using its negative tolerance during operation, the wall thickness of the pipe before bending should be 1.06~1.25 times of the design wall thickness, and the smaller the bending radius, the larger the multiple

2. The bending radius of high pressure steel pipe should be greater than 5 times of the pipe outer diameter, and others should be greater than 3.5 times

3. When the seam steel pipe is bent, the weld should avoid the tensile and compression areas

4. The heat treatment temperature of the bend after bending is 600~650 ℃, and the heating rate, constant temperature time and cooling rate shall be controlled according to the specification

P9 elbow will be heated, expanded and bent in motion after its quenching and tempering and surface nitriding treatment. The manufacturing requirements of small elbow are as follows: the bending radius of small elbow processing elbow shall not be less than times of the nominal diameter of the pipe; However, after bending, cut off according to the length