Eight-shaped head, ingot elbow

Yuanbao elbow, also known as figure-eight head. The elbow is formed by stamping plates of the same material as the pipe into semi-annular elbows using stamping dies, and then assembling and welding the two semi-annular elbows together. Due to the varying welding standards for different types of pipelines, such elbows are usually delivered as semi-finished products with tack-welded assemblies, and on-site welding is performed according to the pipeline weld grade during construction. Hence, they are also referred to as two-half welded elbows.

For Yuanbao elbows and stamped elbows, the processing technology involves applying force from conventional or special stamping equipment to directly deform sheet materials within dies under deformation force, thereby producing parts with specific shapes, dimensions and properties. Sheet materials, dies and equipment are the three essential elements of stamping. Stamping is a cold forming process for metals, so it is called cold stamping or sheet stamping, or stamping for short. It is one of the main methods of metal plastic working (or pressure working) and also falls under material forming engineering technology. The advantages of the Yuanbao elbow manufacturing process are mainly reflected in the following aspects:

1. No pipe blanks are required as raw materials, which saves the cost of pipe-making equipment and dies, and allows the production of carbon steel elbows with arbitrarily large diameters and relatively thin wall thicknesses.

2. The blanks are flat plates or developable curved surfaces, making blanking simple, precision easy to guarantee, and assembly and welding convenient.

3. Due to the above two reasons, the manufacturing cycle can be shortened and production costs greatly reduced. Since no special equipment is needed, it is particularly suitable for on-site processing of large carbon steel elbows.

4. Carbon steel stamped elbows are applicable to pipeline systems in industries such as petroleum, natural gas, chemical engineering, water and electricity, construction and boilers.

First, a polygonal prismatic ring shell with a polygonal cross-section or a closed prismatic sector shell at both ends is welded. After filling the interior with a pressure medium, internal pressure is applied, causing the polygonal cross-section to gradually transform into a circle under internal pressure, forming a circular ring shell. As required, a circular ring shell can be cut into four 90° elbows, six 60° elbows, or elbows of other specifications. This process is suitable for manufacturing any large stamped elbow where the ratio of the mean diameter to the inner diameter is greater than 1.5D, making it an ideal method for producing large elbows at present.

Hebei Renlong Pipeline Fittings Co., Ltd. mainly manufactures and sells: elbows, bends, tees, crosses, reducers, heads and caps, flanges, socket fittings, manholes, bolts, nuts, gaskets and other products.