Weld Neck Flange

A flange—also known as a flange disc or flange—is a component used to connect two shafts or pipe ends; it may also be employed at the inlets and outlets of equipment to link two separate pieces of equipment, such as a reducer flange. A flange connection or flange joint refers to a detachable connection assembly consisting of a flange, a gasket, and bolts, which together form a combined sealing structure. In piping systems, "flange" denotes the flanges used for piping; when applied to equipment, it refers to the inlet and outlet flanges of the equipment. A flange features holes, and bolts secure two flanges together, with a gasket placed between them to ensure sealing. Flanges are categorized into threaded flanges, welded flanges, and clamp flanges. Flanges are typically used in pairs: threaded flanges are suitable for low-pressure piping systems, while welded flanges are used for systems operating at pressures exceeding 4 kg/cm². When connecting a pump or a valve to a pipeline, the respective components of these devices are also fabricated with corresponding flange shapes; such connections are also referred to as "flange connections." Any connecting component that utilizes bolts to secure two planar peripheries while providing a sealed interface is generally termed a "flange"; for example, in the connection of ventilation ducts, such components may be classified as "flange-type components." However, since such a connection constitutes only a localized feature of a device—such as the connection between a flange and a pump—it would be inappropriate to classify the pump itself as a "flange-type component." In contrast, smaller components, such as valves, may be classified as "flange-type components."

1. Classified according to the Chemical Industry (HG) standard: Integral Flange (IF), Threaded Flange (Th), Plate Flat Welding Flange (PL), Weld Neck Flange (WN), Slip-on Weld Neck Flange (SO), Socket Weld Flange (SW), Loose Flange with Welded Ring (PJ/SE), Loose Flange with Flat Welded Ring (PJ/RJ), Lined Blind Flange (BL(S)), Blind Flange (BL) [2].

2. Classified according to the Petrochemical Industry (SH) standard: Threaded Flange (PT), Weld Neck Flange (WN), Slip-on Flange (SO), Socket Weld Flange (SW), Loose Flange (LJ), Blind Flange (unmarked).

3. Classified according to the Machinery Industry (JB) standard: Integral Flange, Weld Neck Flange, Plate Flat Welding Flange, Plate Loose Flange with Welded Ring, Plate Loose Flange with Flat Welded Ring, Plate Loose Flange with Flanged Ring, Blind Flange.

4. Classified according to the National (GB) standard: Integral Flange, Threaded Flange, Weld Neck Flange, Slip-on Weld Neck Flange, Socket Weld Neck Flange, Weld Neck Loose Flange with Welded Ring, Plate Flat Welding Flange, Plate Loose Flange with Welded Ring, Plate Loose Flange with Flat Welded Ring, Plate Loose Flange with Flanged Ring, Blind Flange.

WCB (Carbon Steel), LCB (Low Temperature Carbon Steel), LC3 (3.5% Nickel Steel), WC5 (1.25% Chromium 0.5% Molybdenum Steel), WC9 (2.25% Chromium), C5 (5% Chromium 0.5% Molybdenum), C12 (9% Chromium 1% Molybdenum), CA6NM (12% Chromium Steel), CA15 (4) (12% Chromium), CF8M (316 Stainless Steel), CF8C (347 Stainless Steel), CF8 (304 Stainless Steel), CF3 (304L Stainless Steel), CF3M (316L Stainless Steel), CN7M (Alloy Steel), M35-1 (Monel), N7M (Hastelloy B), CW6M (Hastelloy C), CY40 (Inconel), etc.