Analysis of Stainless Steel Flange Sealing Surface Types

The sealing surface and welding method of a stainless steel flange directly impact the tightness, pressure-bearing capacity, and applicable working conditions of pipeline connections. The three most commonly used types in the industry are slip-on, weld-neck, and socket weld flanges. These types differ significantly in terms of structure, processing techniques, and performance, making them suitable for different applications. Choosing the right connection type of stainless steel flange can avoid pipeline leakage and pressure-bearing failure.

1. Slip-on Stainless steel flange

This type of flange is simple, economical, and suitable for low-pressure conventional working conditions. Its sealing surface can be either flat or raised. During welding, the flange is fitted onto the end of the pipeline, with the weld seam located on the outside. This design makes it easy to construct, with low welding difficulty and cost, resulting in it being the most commonly used basic type of flange.

However, it has average force uniformity, and its tightness and impact resistance are relatively weak. Therefore, it is only appropriate for low-pressure, normal-temperature, and non-corrosive working conditions, such as municipal water supply and drainage systems, as well as civil heating pipelines. It is not suitable for pipelines that handle high pressure, high temperature, or flammable and explosive media.

2. Weld-neck flange

This material is resistant to high pressure and high temperature, making it suitable for harsh industrial conditions. The sealing surface typically features a concave-convex or tenon-groove design. The flange end is beveled to allow for butt welding with the pipeline bevel. The weld penetration is excellent, leading to strong structural rigidity and superior tightness. This design ensures an integral force with the pipeline, offering strong resistance to impact and deformation.

Although it has high requirements for processing and welding, along with a higher cost, its ability to withstand pressure and high temperatures is exceptional. It is particularly suitable for demanding environments such as petrochemical pipelines and high-pressure gas pipelines, making it the top choice for industrial high-pressure pipelines.

3. Socket weld flange

Precision sealing is ideal for small-diameter, high-pressure applications. The sealing surfaces can be either flat or raised. In this design, the pipeline fits securely into the flange socket and is welded in place, ensuring a tight connection. This method provides superior tightness and precision compared to slip-on flanges, while also featuring a compact structure that conserves space. It is specifically designed for small-diameter pipelines operating under high pressure or normal temperature conditions, such as instrument pipes and small-diameter chemical process lines. Due to the complexities involved in installation and welding, this type of flange is generally not recommended for large-diameter pipelines.

Selection reminders: Prioritize selection according to pipeline pressure and medium; Choose according to diameter and installation space; Match the corresponding gasket to improve sealing effect; For corrosive working conditions, prefer 316 material to extend the service life of stainless steel flange.