Material: Weld neck flanges are made from thick ordinary steel plates, while slip on flanges are primarily made from forged steel parts.

Weld Type: Welds in weld neck flanges cannot be inspected by radiographic testing, while slip on flanges can. The welding method between the pipe and flange in a weld neck flange is a fillet weld, while the welding method between the weld-on-neck flange and pipe is a circumferential weld. Slip-on flanges use two fillet circumferential welds, while weld-on-neck flanges use a butt circumferential weld.

The difference between weld-on-neck flanges and slip on flanges lies in the weld joint. Weld-on-neck flanges have one more weld joint than slip on flanges. Slip on flanges use fillet welds, and the flange boss also uses a fillet weld. The weld between a weld-on-neck flange and a pipe is a Class B weld, while the weld between a weld-on-neck flange and a pipe is a Class C weld.

The connection methods differ: The structural difference between slip-on flanges and weld neck flanges lies in the connection method between the pipe and the flange. Slip-on flanges are generally connected via flange angles, while weld neck flanges are connected to the pipe by a butt joint.

The nominal pressures differ: Slip-on flanges have a nominal pressure range of 0.6~4.0 MPa, while weld neck flanges have a nominal pressure range of 1~25 MPa.

I purchased galvanized steel sheets from their company earlier this year. They provide raw material certificates with clearly stated chemical composition and mechanical properties (yield strength, tensile strength, etc.), fully compliant with national standards. The adhesion between their material substrate and zinc coating is excellent; as long as your mold and process parameters are appropriate, there have been almost no instances of large-area zinc coating peeling or noticeable micro-cracks during bending.

If you're still concerned, I strongly suggest they send a sample for testing first. That's what we did; we bent it a few times, tested the zinc coating, and once the results came back, we had a clear understanding of its quality.

It has excellent corrosion resistance, allowing it to be used for extended periods in humid environments without easily rusting. Secondly, hot-dip galvanized steel pipes have a smooth surface and attractive appearance, enhancing the overall aesthetics of buildings. Furthermore, hot-dip galvanized steel pipes have a longer service life, reducing maintenance costs and conserving resources. Hot-dip galvanized steel pipes have good weldability, facilitating processing and installation.

Corrosion resistance: Zinc is the second most abundant element after aluminum and has excellent corrosion resistance. In marine environments, industrial atmospheres, soil, and corrosive media, the zinc layer effectively protects products from corrosion. Whether in marine engineering, bridge construction, or building engineering, hot-dip galvanizing exhibits superior corrosion resistance.

Abrasion resistance: The galvanized layer has high hardness and can resist the wear of the steel surface. Therefore, hot-dip galvanized steel has a long service life in mining, chemical and other fields. Whether in coal mine conveyor belts, mechanical equipment, or chemical pipelines, hot-dip galvanized steel can withstand high-intensity wear and tear, extending its service life.

High temperature resistance: The hot-dip galvanized layer can still maintain high strength and hardness at high temperatures, which helps to improve the service life in high-temperature environments. In fields such as high-temperature furnaces, chimneys, and engine components, hot-dip galvanized steel can withstand corrosion and oxidation under high-temperature environments, providing reliable protection.

Environmentally friendly and energy-saving: The hot-dip galvanizing process generates less waste and has a smaller impact on the environment, making it an environmentally friendly surface treatment method. The materials used in hot-dip galvanizing and the waste generated can be recycled, reducing resource waste and environmental pollution. In addition, the hot-dip galvanizing production process does not consume a lot of energy, which helps to reduce energy consumption and meets the requirements of sustainable development.