What Conditions Should The Welding Rods Of Stainless Steel Elbow Pipe Fittings Meet

The welding rods used in stainless steel elbows should be kept dry during use. Titanium calcium type should be dried at 150℃ for 1 hour, and low hydrogen type should be dried at 200-250℃ for 1 hour (do not repeat drying for many times, otherwise the skin will crack and peel off easily). Prevent the welding rod skin from sticking oil and other dirt, so as not to increase the carbon content of the weld and affect the quality of the weldment. When welding elbows, carbides are precipitated by repeated heating, which reduces the corrosion resistance and mechanical properties. The hardening property after welding is large and cracks are easy to occur. If the same type of welding rod is used for welding, preheating above 300℃ and slow cooling treatment of about 700℃ after welding are required. If the weldment cannot be heat treated after welding, chromium-nickel stainless steel welding rods should be used.

Stainless Steel Weld Elbow is the weak link in the pipe system. The performance of the pipeline is mainly determined by the working capacity of the stainless steel elbow. The working capacity of the stainless steel elbow is related to the stress state it is in. Calculation and on-site measurement of working stress of pipe fittings show that the arc starting point of stainless steel elbow is particularly sensitive to external loads. In addition to the external loads such as internal pressure and deadweight, the main external loads are caused by the thermal expansion of pipe metal during the startup process, pipe vibration and abnormal operation of supports and hangers. When the arc starting section of the stainless steel elbow is a butt weld, these variable external loads will cause the weld to be in a complex stress state, seriously weakening the weld strength, reducing the working capacity of the stainless steel elbow, and shortening the service life of the stainless steel elbow. For this reason, from a design perspective, the interface of the butt-welded stainless steel elbow is changed to a straight section butt, that is, the design of a stainless steel elbow with a straight section is conducive to the butt weld, improving the weld quality, and improving the service life of the stainless steel elbow.