Introduction to Pipe Fittings in China

In China, fittings with a nominal pressure rating (DN) of ≥16 MPa are classified as high-pressure fittings. These fittings are used in specialized applications such as high-pressure steam equipment, high-temperature and high-pressure chemical pipelines, pressure vessels in power plants and nuclear power stations, and components for high-pressure boilers. For pipes and fittings with a nominal diameter (DN) of ≤40, since their wall thickness is typically quite thin, butt welding can result in significant misalignment, increase the risk of burn-through, and make it difficult to ensure consistent weld quality. Therefore, butt welding is generally avoided in such cases. For the same product, the material weight differs: machining requires 10.35 kg, whereas using pipe fittings reduces this to 9.32 kg, resulting in savings of…

In China, fittings with a nominal pressure rating (DN) of 16 MPa or higher are classified as high-pressure fittings. These fittings are employed in specialized applications such as high-pressure steam equipment, high-temperature and high-pressure chemical pipelines, pressure vessels in power plants and nuclear power stations, and components for high-pressure boilers, among others.

For pipes and fittings with a nominal diameter of DN≤40, since their wall thickness is typically relatively thin, butt welding can result in significant misalignment, increase the risk of burn-through, and make it difficult to ensure consistent weld quality; therefore, butt welding is generally not recommended in such cases.

For the same product weight, the material usage differs: machining requires 10.35 kg, whereas using pipe fittings reduces it to 9.32 kg, resulting in material savings. The unit cost of a machined part is 20 yuan, while a pipe‑fitting‑based part costs only 10 yuan. Consequently, the pipe‑fitting approach offers a significant price advantage, cutting costs by nearly 50%.

Many processes still fall under the category of mechanical machining, with the most commonly used methods being stamping, forging, roll forming, roll‑rolling, bulging, drawing, bending, and combined machining. Pipe fitting fabrication represents an integrated combination of machining and metal forming processes.

The rapid development of pipe fittings can be attributed to the following factors: First, they can replace certain machined components while being lighter than machined parts, castings, and forged structural components, thereby saving materials. Second, they reduce the number of processing steps and labor hours compared with machined products, thus lowering production costs.

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Working capacity of the elbow joint

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