Home >> News

How to do Passivation Treatment of Large Flange?

Jul. 14, 2020

Large flanges refer to flanges that exceed the size prescribed by the relevant state departments. Generally refers to the flange above DN2000. This kind of flange needs to be produced by the construction party to produce. There are two production processes: forging and rolling. The material is stainless steel, carbon steel, and alloy steel.

Stainless steel flange wholesale, as a sealing and fastening connector, is widely used in large containers in aerospace, petroleum, chemical, and other fields. Although the processing capacity is not considered, for large flanges, due to the size is too large, only for transportation reasons, the overall processing of large flanges is impossible and needs to be separated. The large flange connection is easy to use, can withstand a lot of pressure, and plays an important role and value in use. In industrial pipelines, large flange connections are widely used.

The passivation process of large flanges can be divided into wet and dry methods. It can be divided into many types. The passivation of large flanges depends not only on the passivation process but also on the material of the large flange itself. The specific influencing factors are elements in large flanges, stainless steel metallographic structure, stainless steel processing status, etc. Among the constituent elements, chromium and nickel are strong passivating elements, followed by iron. Therefore, the higher the chromium and nickel content, the stronger the passivation of stainless steel. The large flanges of austenite and ferrite have a uniform structure and good passivation. The martensitic stainless steel is strengthened by heat treatment, and its metallographic structure is a multiphase structure, so the passivation is not strong.

Stainless Steel Flange

Stainless Steel Flange

The large flanges are in good condition after processing, and the forgings and sandblasting are generally rough, and they are dull and dull.

The raw material of large flanges not only has an acceptable creep and rupture curve but also its pipeline price is moderate. The form of reliable mutual melting and fusion connection is reliable. The diameter of the pipe is larger than the inner diameter of the pipe of different specifications. Compared with other varieties, the construction is convenient and fast. The connection form belongs to the current stage. The system is in a mechanical connection without partial contraction, so the fluid resistance of the system is small.

The long-term pressure resistance of large flanges can only be better if the large flanges of high-pressure flange manufacturers withstand the pressure from the design stress. However, due to various factors, the actual wall thickness of the floor heating pipe is usually only 2 mm. Under this wall thickness, various pipes can meet the requirements of floor heating, and the resistance advantage of large flanges is easy to show.

Low-temperature thermal shock resistance of large flanges: The low-temperature impact machines of PE-RT and PEX products can resist well. In the winter construction, the pipeline is not easy to be impacted and broken, thereby increasing the flexibility of construction placement.

Environmental protection of large flanges: PE-RT can run cyclically without polluting the environment. If PEX cannot be recovered, secondary pollution will occur.

BSP Fittings supplier introduces how to do the passivation of large flanges, and hopes the above will help you.