Concentric heads

The big head on the same straight line is called concentric little head. Usually, the forming process is shrinkage pressing, expanding pressing or shrinkage and expanding pressing. For some specifications of different diameter pipes, stamping can also be used.

Concentric pipe, also known as concentric pipe with different diameter, is used to connect pipes of different sizes. Generally, it is divided into concentric pipe with different diameter and eccentric pipe with different diameter.

The quality of concentric and different diameter pipes shall conform to the current standard "Steel butt welded seamless fittings" GB/T 12459-2005, and shall meet the following requirements:

1) The roundness of concentric pipe with different diameters should not be greater than 1% of the outer diameter of the corresponding end, and the allowable deviation should be <3 mm. The center lines of the two ends of concentric pipe with different diameters should coincide, and the allowable deviation of the eccentricity should be <5 mm.

2) the appearance of concentric reducer can not be cracked or heavy, and the wall thickness should be larger than that of the large diameter end pipe section.