Structural Characteristics

The stainless steel necked flange consists of a flange plate, neck, and bolt holes, among other parts. The presence of the neck provides better strength and stability when connecting to pipelines, allowing it to withstand greater pressure and stress. Bolt holes are evenly distributed on the flange plate for connection with other flanges or equipment, achieving sealing and fixation by tightening the bolts.

Material Advantages

Strong corrosion resistance: Stainless steel itself has excellent corrosion resistance, able to withstand erosion from various media such as atmosphere, water, acids, alkalis, and salts. Therefore, stainless steel necked flanges are particularly suitable for harsh corrosive environments, such as in the chemical, marine engineering, food processing, and pharmaceutical industries, ensuring the long-term stable operation of pipeline systems and reducing issues like leaks caused by corrosion.

High strength: Stainless steel has high strength and hardness, and after appropriate processing and heat treatment, its mechanical properties can meet the requirements of various high-pressure and high-temperature pipeline systems. When subjected to high-pressure fluids, stainless steel necked flanges can maintain good sealing performance, ensuring the safety and reliability of the pipeline system.

Aesthetic and hygienic: The surface of stainless steel is smooth and shiny, with good appearance quality, which not only enhances the aesthetics of the entire pipeline system but also meets strict hygiene standards in industries with high hygiene requirements, such as food and pharmaceuticals, due to its easy cleaning and low bacterial growth characteristics.

Types

Plate type flat welding neck flange: This type of flange has a simple connection between the neck and the flange plate, with relatively easy manufacturing processes and lower costs. It is suitable for pipeline systems with lower pressure ratings and temperatures, generally used in situations with nominal pressure PN≤1.6MPa and temperatures not exceeding 200℃.

Welding neck flange: The neck of the welding neck flange is connected to the flange plate by a butt weld, providing better strength and sealing, capable of withstanding higher pressure and temperature. It is commonly used in pipeline systems with nominal pressure PN≥1.6MPa and higher temperatures, such as high-temperature steam pipelines and high-pressure chemical pipelines. This type of flange requires butt welding during installation, with high requirements for welding processes and quality.

Sealing Surface Types

Raised face (RF): The sealing surface of a raised face flange is a protruding smooth plane, which achieves sealing by closely fitting with the raised face of another flange through a gasket during installation. This sealing surface type has a simple structure, is easy to process, and is widely used, but its sealing performance is relatively average, suitable for medium and low-pressure, normal temperature pipeline systems.

Convex-concave surface (MFM): The convex-concave surface flange consists of a concave surface and a convex surface, where the convex surface is inserted into the concave surface during installation, with a gasket for sealing. This structure provides better sealing performance, suitable for higher pressure and flammable, explosive, or toxic media, but requires higher processing precision, and manufacturing and installation costs are relatively high.

Tongue and groove surface (TG): The sealing surface of a tongue and groove flange consists of a tongue surface and a groove surface, which fit together to form a seal. Its sealing performance is superior to that of convex-concave flanges, effectively preventing media leakage, but it has greater processing difficulty, and special attention is needed for the fit precision during installation. It is commonly used in pipeline systems with extremely high sealing requirements, such as high-purity media transport pipelines in the chemical and pharmaceutical industries.

Application Fields

Chemical industry: In chemical production, various corrosive media transport pipelines usually choose stainless steel necked flanges. For example, in pipeline systems transporting strong corrosive chemicals like sulfuric acid, hydrochloric acid, and caustic soda, stainless steel necked flanges can ensure the sealing and corrosion resistance of the pipelines, preventing chemical leaks and ensuring the safety and stability of the production process.

Food processing industry: The food processing industry has extremely high hygiene and cleanliness requirements. The smooth surface and good corrosion resistance of stainless steel necked flanges make them an ideal choice for food pipeline systems. They can meet the strict hygiene standards of the food industry, preventing food contamination and ensuring food quality and safety.

Pharmaceutical industry: In the pharmaceutical production process, many drugs need to be produced and transported in a sterile and uncontaminated environment. The hygienic performance and corrosion resistance of stainless steel necked flanges make them widely used in pharmaceutical pipeline systems, such as the transport of pharmaceutical raw materials and connections between pharmaceutical equipment, ensuring the quality of drugs and the reliability of the production process.

Marine engineering: In marine environments, seawater is highly corrosive and faces harsh conditions such as high pressure and salinity. Stainless steel necked flanges can resist seawater corrosion, ensuring the normal operation of various pipeline systems in marine engineering, such as seawater desalination systems on ships and oil transport pipelines on offshore oil platforms.