Structural Characteristics

The flat welding flange consists of a flange plate and a bevel for connecting pipes. The flange plate has evenly distributed bolt holes for connecting to other flanges or equipment. The connection method with the pipe is flat welding, which involves inserting the pipe into the bevel of the flange plate and then welding on the outside, forming an integral connection between the flange and the pipe.

Advantages

Simple manufacturing: The manufacturing process of flat welding flanges is relatively simple, requiring no complex processing equipment and technology, resulting in lower production costs. Its simple structure makes it easy to design and manufacture, meeting the connection needs of pipes with different specifications and pressure ratings.

Easy installation: Since the connection between the flat welding flange and the pipe is completed through flat welding, the installation process is relatively easy. No special installation tools or techniques are required; ordinary welding equipment and workers can complete the installation, significantly improving installation efficiency and shortening construction time.

Strong adaptability: Flat welding flanges can adapt to connections with various materials of pipes, such as carbon steel, stainless steel, and alloy steel. By selecting appropriate welding materials and processes, good welding performance between different materials can be ensured, achieving reliable connections.

Disadvantages

Relatively low strength: Compared to some other types of flanges, flat welding flanges have relatively low strength. When subjected to high pressure and stress, issues such as deformation and leakage may occur. Therefore, flat welding flanges are generally suitable for pipe systems with lower pressure ratings, such as those with a nominal pressure of PN≤1.6MPa.

Limited sealing performance: The sealing performance of flat welding flanges mainly relies on gaskets, and their sealing surfaces are usually flat or raised, resulting in relatively average sealing effects. In situations where sealing requirements are high, such as in pipeline systems transporting flammable, explosive, or toxic substances, additional sealing measures may be necessary, or other flange types with better sealing performance may need to be selected.

Sealing Surface Types

Flat sealing surface (FF): The flat sealing surface is the simplest type of sealing surface in flat welding flanges, with a smooth flat surface. During installation, a gasket is placed between the two flange surfaces, and bolts are tightened to compress the gasket, achieving sealing. The advantage of flat sealing surfaces is their simple processing and low cost, but their sealing performance is relatively poor, suitable for low-pressure, non-toxic media, and systems with low leakage requirements.

Raised sealing surface (RF): The raised sealing surface features a raised annular platform machined on the sealing surface of the flange plate, with the gasket placed on the raised surface. This type of sealing surface can provide better sealing effects than flat sealing surfaces because the raised surface can better compress and position the gasket. The processing difficulty and cost of raised sealing surfaces are slightly higher than those of flat sealing surfaces, suitable for medium to low pressure and normal temperature general industrial pipeline systems, and is one of the most widely used sealing surface types in flat welding flanges.

Application Fields

Building water supply and drainage systems: In the water supply and drainage pipelines within buildings, flat welding flanges are commonly used to connect pipes of different diameters, such as water supply networks and drainage networks. Their simple manufacturing and easy installation characteristics can meet the connection requirements of building water supply and drainage systems, while their pressure ratings and sealing performance can also meet usage needs in general building environments.

HVAC systems: In HVAC systems, ductwork, water pipes, and other pipeline connections often use flat welding flanges. Flat welding flanges can conveniently connect pipes of different specifications, forming a complete ventilation and air conditioning system. In non-corrosive environments, flat welding flanges can reliably transport air, cold water, hot water, and other media, ensuring the normal operation of the system.

General industrial pipeline systems: In some industrial fields where pressure and sealing requirements are not particularly high, such as light industry and textiles, flat welding flanges are also widely used. The pipeline systems in these industries typically transport general media such as water, steam, and air, and flat welding flanges can meet their basic connection and usage requirements, while their lower cost can also reduce investment in engineering construction.