When welding steel pipes, you need to pay attention to the following matters:

First, clean the surface of the steel pipe. Before welding, make sure the surface of the steel pipe is clean and free of oil, paint, water, rust, and other impurities. These impurities may affect the smooth progress of welding and may even cause safety issues. Tools such as grinding wheels and wire brushes can be used for cleaning.
Secondly, the adjustment of the bevel. According to the wall thickness of the steel pipe, adjust the shape and size of the welding groove. If the wall thickness is thicker, the groove can be slightly larger; if the wall thickness is thinner, the groove can be smaller. At the same time, the smoothness and flatness of the groove should be ensured for better welding.
Third, choose the appropriate welding method. Choose the appropriate welding method according to the material, specifications, and welding requirements of the steel pipe. For example, for thin plates or pipes of low-carbon steel, gas-shielded welding or argon arc welding can be used; for thick plates or steel structures, submerged arc welding or arc welding can be used.
Fourth, control the welding parameters. Welding parameters include welding current, voltage, welding speed, etc. These parameters should be adjusted according to the material and thickness of the steel pipe to ensure welding quality and efficiency.
Fifth, pay attention to preheating and post-welding treatment. For some high-carbon steel or alloy steel, preheating treatment is required before welding to reduce welding stress and prevent the occurrence of cracks. Post-weld treatment includes weld cooling, welding slag removal, etc.

Finally, follow safe operating procedures. During the welding process, attention should be paid to safe operating procedures, such as wearing protective clothing, gloves, and masks. At the same time, welding equipment should be inspected and maintained regularly to ensure its normal operation.