Plate flat welding large-diameter flange is a common pipeline connection component, usually referring to plate flat welding flanges with a nominal diameter DN greater than or equal to 300mm. Here is a detailed introduction about it:

structural characteristics

Plate flat welding flange is a flat flange without a neck, which is only connected to the pipeline by fillet welding of the flat plate, and has a simple structure. This structure makes it lighter in weight, with fewer consumables and no neck transition. The overall weight is 20% to 30% lighter than a flange with a neck and flat welding.

The manufacturing cost is low, with no neck structure, eliminating processes such as plate rolling and groove processing. The material utilization rate is high, and the unit price is about 50% to 60% of that of welded flanges with necks. Easy and efficient installation, the pipeline can be welded by inserting it into the inner hole of the flange without high-precision alignment. A single person can complete a single set of welding in 20-30 minutes, saving 40% of labor time compared to a flange with a neck.

common standard

The national standard includes GB/T 9119-2020 "Flat Welded Steel Pipe Flanges", and the chemical industry standard includes HG/T 20592-2009 "Steel Pipe Flanges (PN Series)", etc.

Specifications and Dimensions

According to the GB/T 9119-2020 standard, for plate flat welding flanges with nominal pressures of PN1.0MPa and PN1.6MPa, the outer diameter of the DN300 flange is 440mm, the diameter of the bolt hole center circle is 400mm, the number of bolt holes is 12, the bolt hole diameter is 26mm, and the flange thickness is 30mm; the outer diameter of the DN2000 flange is 2325mm, the diameter of the bolt hole center circle is 2230mm, the number of bolt holes is 48, the bolt hole diameter is 60mm, and the flange thickness is 84mm.

Application field

Mainly used in batch construction scenarios such as building water supply and drainage, air conditioning water systems, as well as large-diameter and low-pressure pipelines such as municipal water supply networks. In industries such as chemical, petroleum, and power, it is also used for pipeline connections that do not require particularly high pressure and sealing requirements.

production process

There are mainly forging, casting, cutting, rolling, etc. Among them, flanges made by forging technology, such as forged plate flat welding flanges, have more stable organizational structure and mechanical properties, and are suitable for withstanding high pressure, high temperature, and chemical corrosion environments.