Precautions for steel pipe welding

Posted by chase Liu on September 1st, 2023

Seamless pipes or welded steel pipes often need to be welded first to meet the requirements of practical applications. Steel pipes are widely used in petroleum, natural gas, chemical industry, electric power, aerospace and other fields (such as octg pipe). There are many things you need to know about steel pipe welding, and you must take comprehensive considerations into account when handling them, and handle them properly based on actual application needs. So what are the precautions for steel pipe welding? How to ensure the smooth progress of welding?

1. Align the axes of the two pipes before welding: first spot weld the ends of the two pipes firmly. If the pipe diameter is below 100mm, you can spot weld three spots. If the pipe diameter is above 150mm, you can spot weld four spots.

2. If the wall thickness of the pipe is more than 5mm, the pipe end should be beveled. If an air pad is used to process the pipe bevel, the oxide scale on the bevel surface must be removed, and the uneven areas that affect the welding quality must be smoothed.

3. When welding the pipe and the flange, insert the pipe into the flange first, spot weld at 2-3 points, and then level with a square before welding. The flange must be welded on both sides, and the inner flat seam must not protrude from the flange sealing surface.

4. When welding pipes, measures must be taken to prevent wind, rain and snow. The ambient temperature of the welding area is lower than -20°C. The welding joint must be preheated. The preheating temperature is 100-200°C and the preheating length is 200-250mm.