Polishing method for dual phase steel flanges

Time

2023-06-13 09:44

Source:

1. There are four polishing methods for dual phase steel flanges: manual, mechanical, chemical, and electrochemical. Polishing can improve the corrosion resistance and decoration of flanges. The existing stainless steel electric polishing fluid still uses phosphoric acid and chromic anhydride. During the polishing and cleaning process, some chromium and phosphorus will be discharged into the wastewater, causing pollution to the environment.
2. The surface of the dual phase steel flange will form a passivation film, while the oxide film begins to dissolve. Due to the inconsistent microstructure of the dual phase steel flange surface, the slightly convex part of the surface preferentially dissolves, and the dissolution rate is greater than that of the concave part. The film dissolves and forms almost at the same time, but its speed is different. The result is that the surface roughness of the dual phase steel flange decreases, resulting in a smooth and glossy surface.
3. Polishing can fill some surface defects such as pores and scratches, thereby improving fatigue resistance and related corrosion resistance. The yield strength of dual phase steel flanges is more than twice that of austenitic stainless steel, and there is also sufficient plasticity required for this molding, as well as superior resistance to stress corrosion cracking, especially in chloride ion environments.

PRE

How to anneal butt welded flanges

NONE

PRE

How to anneal butt welded flanges

NONE

2023-06-13

Stainless steel flanges are flanges that extend steel pipes, pipe fittings, etc. into the flanges and are connected to equipment or pipelines through fillet welds. The inner hole on one side of the flange is provided with a welding boss, and the welding boss is provided with an inner hole. The inner hole communicates with the inner hole in the center of the flange, and there is elasticity between the flange and the welding boss. The two top surfaces of the elastic ring are respectively combined with the flange and the welding boss. There are many screw holes on the flange. The screw holes are symmetrically distributed around the center of the flange. The stainless steel flange is made of stainless steel, followed by a polyethylene plastic layer, a rubber layer and a PVC layer. Here we take a look at the use of stainless steel flange precautions. 1. In order to prevent corrosion between eyes caused by heating of stainless steel flanges, the welding current should not be too large, about 20% less than carbon steel electrode, the arc should not be too long, the cooling speed is between the number of layers, and the narrow bead effect is better.

Advantages and disadvantages of flat welding flange

2023-06-13

Flat welded flanges are mainly used for gas valves and natural gas pipelines. Because the short neck can improve the rigidity and carrying capacity of the flange. Flat welded flanges are used for general media. Flat welding flange with neck is suitable for flammable, explosive, corrosive and toxic places. The sealing surface of flat welding flange can be convex surface, concave convex surface and tongue and groove surface. They are different in structure, sealing effect and strength. Flat welding flange is generally called flat plate, also known as lap welding flange. The connection between the flat welding flange and the pipe is to insert the pipe into the flange inner hole to the appropriate position before the lap welding. The characteristics of flat welding flange: flat welding flange not only saves space, reduces weight, but also ensures no leakage at the joint and good sealing performance. The reason for the reduced size of the compact flange is the reduced diameter of the seal, which will reduce the cross section of the sealing surface. The advantages of flat welding flanges are as follows:

Applicable scope and purpose of welding flange