Welding elbow pipe fitting material production is a kind of special electric, magnetic, force, chemical and biological functions of new materials, is biotechnology, information technology, power technology and other high-tech categories and the national defense construction of the important basic materials such as agriculture, chemical, building materials play an important role.Butt welding elbow pipe fittings are special materials, showing different application values in different categories, and affecting the development of other operations to some extent.Porosity: When the weld metal is at high temperature, it absorbs too much gas (such as H2) or gas (such as CO) due to the metallurgical reaction in the molten pool. When the molten pool is cooled and solidified, it is too late to be discharged, and holes are formed in the interior or surface of the weld, which is called porosity.The existence of porosity reduces the effective working section of weld and the mechanical strength of joint.If there is penetration or continuous porosity, it will seriously affect the sealing of welding parts.

After completion of welding construction operation, anti-rust or anti-corrosion treatment should be carried out according to the actual situation or the external environment of the pipeline, so as to prevent corrosion or corrosion of the elbow pipe at the weld, resulting in too short service life of the elbow pipe.Before welding butt welding elbow fittings, in order to prevent welding deformation during factory operation, the two ends of outer tiles on both sides of the assembled whole elbow fittings should be aligned and reinforced with stainless steel arc plate and keel.According to the conventional welding technique, argon filling welding is needed. Considering the welding cost and the large diameter of shrimp waist pipe, it is difficult to fill argon. By summing up the above factors, two welders inside and outside are selected for symmetrical welding, which not only deals with the argon filling problem well, but also has a good shape.