Pros and Cons of Stainless Steel Flanges

Flanges applied connections are the most essential and common methods to connect various vessels and industrial pipelines. To meet the requirements of production process or be convenient for manufacture, transportation, installment and inspections, vessels and pipelines are usually connected by removable structures, that is, flanges. This is because flanges have great strength, compactibility as well as a wide range of applicable sizes. Therefore, it is widely used by enterprises who manufacturing salts under vacuum conditions.

In some cases, media inside vessels and pipelines may have strong corrosiveness. Although carbon steel flanges are ductile and can be easily sheared, it can hardly resist corrosion. Usually it will be largely corroded after being used one month. Six months later, a large scale of perforation will occur and result in leakages of media.  

 

The disadvantages of stainless steel flanges:

1.High prices. The stainless steel flanges are always 3 to 5 times more expensive than carbon steel ones.

2.High demand for welding techniques. Poor welding leads to cracks.

3. At present, there are titanium carbides in stainless steel flanges. This fact degrades the ductility, toughness and stamping ability of materials. Misuse will break flanges.

 

For stainless steel valves, connecting with pipelines through flanges are the most common methods. In these cases, valves are equipped with flanges on both of ends. In general, they are referred to as flanged valves. These flanged ends correspond to flanges of pipelines. Therefore, valves can be fixed to pipelines by bolts with assistance of flanges. 

 

Flanges can be divided into RF flanges, FF flanges and MF flanges. In terms of different surfaces, they can be divided into the following six kinds: 

1)Smooth styles: This kind of flanges are used for connecting stainless valves of low pressures. They are convenient for process. 

2)Concave-convex styles: Concave-convex flanges boast of high work pressures and can be used together with medium-hard gaskets.

3)Mortise styles: Mortise flanges can be used with ductile and flexible washers. With great seal ability, they are widely used in working environment where corrosive media exist. 

4)Trapezoidal-groove styles: Trapezoidal-groove flanges use oval ring gaskets. They apply to valves of high temperature or over 64kg/cm² working pressures.

5)Lens styles: Lens flanges have lens-shaped metallic washers. They work with valves of high temperature or of high pressure of over 100kg/cm².

6)O-ring styles: This is a new joint method that evolving with the appearing of various rubber O-rings.