Precautions for butt welding elbow

　　In a piping system, an elbow is a fitting that changes the direction of the pipe run. According to the angle, there are three commonly used elbows: 45 ° and 90 ° 180 °, and other abnormal angle elbows such as 60 ° are also included according to the needs of the project. Elbow materials include cast iron, stainless steel, alloy steel, malleable cast iron, carbon steel, non-ferrous metals and plastics. The connection methods with the pipe include: direct welding flange connection, hot-melt connection, electric fusion connection, threaded connection and socket connection, etc. According to the production process, it can be divided into: welding elbow, stamping elbow, push elbow, casting elbow, butt welding elbow, etc. Other names: 90 degree elbow, right angle bend, love bend, etc.

　　The welding rod for butt welding elbow shall be kept dry during use. The titanium calcium type shall be dried at 150 ℃ for 1 hour, and the low hydrogen type shall be dried at 200-250 ℃ for 1 hour (repeated drying is not allowed, otherwise the skin is easy to crack and peel off), so as to prevent oil and other dirt on the electrode skin, so as not to increase the carbon content of the weld and affect the quality of the weldment. In terms of varieties, general-purpose pipes are more than 1.9 million tons, accounting for 55%; 770000 tons of oil pipes, accounting for 6%; More than 150000 tons of hydraulic props and fine pipes, accounting for 4.5%

　　Stainless steel stamping elbow fittings, bearing pipes and automobile pipes account for 50000 tons, accounting for 1.5%. The billet is sent into the furnace for heating, the temperature is about 1200 ℃, and the fuel is hydrogen or acetylene. The temperature control in the furnace is the key problem.