How do we weld the socket weld flange with pipes?
How do we weld the socket weld flange with pipes？Socket weld flange will normally be inserted into the flange of the pipe welding, butt welding is used in welding flange, the pipeline and docking surface will be butt welded, socket welded joints can not be done radiographic inspection, butt welding can do, so for high weld seam detection requirements will be recommended butt welding flange. General welding requirements is higher than socket welding requirements, and welding quality is better, but detection means also more strict. Welding need to do radiographic inspection, socket welding just need to do magnetic powder or penetrant testing (like carbon steel to do magnetic powder, stainless steel for infiltration).
If the fluid flow in the pipeline is not high, it is recommended to use socket welding, convenient for detection, socket welding connection forms are mainly used for valves and pipelines, pipe fittings and pipe welding. General pipe wall thickness is thinner, prone to the wrong side and ablation, difficult for welding, more suitable for socket welding. In addition, the mouth of socket welding has the role of reinforcement, so often use under high pressure. But socket welding also has disadvantages, one is the post weld stress state is not good, easy to weld not fully, the pipe system to leave gaps, Therefore, the pipeline system used for crevice corrosion sensitive medium and the piping system with high cleanliness requirements are not suitable for socket welding. Moreover, the ultra-high pressure pipe, pipe wall thickness is also very large, can use weld the connection to avoid socket welding as far as possible.In short, socket welding formed a fillet weld, and butt welding formed the butt weld. From the strength of the weld, stress conditions butt welding is better than socket welding, so in high pressure level occasions and bad occasions should be used in the form of butt welded, welding and socket welding, details pls See "hg20605-97"
Choose the proper flange material for the piping material, for example, stainless steel pipeline is certainly not allowed to choose the flange such as carbon steel;
According to the nominal diameter (DN) of the pipe and the nominal pressure (PN) of the piping in the whole piping system, the standard system and the European standard system are basically adopted in the international pipe flanges.
According to the specific operating conditions to choose the structure of the flange: such as welding neck flat flange, lap joint flange, sealing surface form has RF, MFM, tongue and so on.
For non-standard parts, it is necessary to design and manufacture according to the standard design procedure flange.