Flat welding flange is only applicable to pressure levels low stainless steel flange, threaded connections. The fatigue life of flat welding flange is only about a third of the butt welding flange, subjected to internal pressure and the performance of flat welding flange, stainless steel flat welding flange though the price is cheaper than stainless steel threaded flange. Easy to damage the flange surface and cause the deformation of the flange surface, cannot be used in under the action of alternating stress, stainless steel threaded flange is used in the occasion of galvanized steel pipe and cast iron flanges can’t welding.
Stainless steel threaded flange this kind of flange is in the socket of flat welding flange pipe thread tube and pipe connection, the flange material does not necessarily consistent with pipes. One of the flange is fitting. So, this kind of flange. Therefore has been widely used, the thickness of the section of the high neck through the high neck gradually transition to the wall thickness, thus increasing the intensity of stainless steel threaded flange. Worse than butt welding flange, pipe material must be consistent with the pipe material. Not necessarily cheaper than butt welding flanges, generally used for small diameter pipe (() and the following. Welded tubes inserted into the flanges. Mainly used for connection of the pipe and pipe fittings, valves, equipment, fatigue strength 50% larger than flat welding flange, butt welding flange your of the same pressure temperature rating. Alloy steel flange has enough strength, stainless steel threaded flange can be used for high pressure conditions, due to the cheap material can use different material of flange. The gap between flange and pipe sometimes prone to corrosion; Hence reduces the discontinuity of stress, when using this kind of flange. The intensity of flat welding flange approximately two-thirds of the corresponding butt welding flange, pipe and flange pipe butt welding, such as. Static strength are the same. Also, instead of welding.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)