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Fittings are components used in piping systems for functions such as connection, control, directional change, diversion, sealing, and support. They are made of materials including steel, stainless steel, and plastic, and can be classified into types such as butt welding, socket welding, threaded, and flanged based on their structure. Their performance directly impacts the safety and operational efficiency of piping systems.
Based on their application, they can be categorized into six types: connection-type (e.g., flanges), direction-changing-type (e.g., elbows), and diameter-changing-type (e.g., reducers), among others. Connection methods include welding, threaded, clamp, and other nine types. The combination of metal and non-metal materials can accommodate different media and pressure requirements, making them widely used in industries such as petrochemicals, municipal engineering, nuclear power, and shipbuilding. Cangzhou, China, has established a manufacturing cluster focused on special steel and plastic fittings, driving the industry toward high-end development.
The pipe fitting standards system was initially divided into two major systems: European (DIN) and American (ANSI). The ISO 7005-1 international standard was established in 1992 by integrating the two systems. China has gradually established the GB/T series of national standards, covering manufacturing and testing requirements for steel and plastic pipe fittings, and implements them in parallel with international standards such as ASME and DIN, supporting the standardization of global pipeline engineering technology.