Carbon steel pipe welding

Generally, carbon steel pipe has a good welding ability. carbon steel pipe welding means a metal material in some welding under the process conditions, the ability to obtain high-quality welded joints. As long as the right choice for mild steel, welding materials (electrodes) and the welding process, will be able to weld a satisfactory joint.

1. Preheat mild steel weldability, and generally it did not require preheating, and only failed in the base metal components (sulfur, phosphorus content is too high), thick-walled, which just had a large welding ambient temperature is too low, only to be taken some warm-up measures. Cold welding, in order to prevent the generation of weld cracking and brittle fracture, the measures taken on the process first warm-up. When the temperature is below 0 °C the construction site, the higher the carbon content of the parent material and the wall is thick, should be considered a warm-up problem. To increase in the low-temperature welding welding current, lower welding speed, continuous welding.

2. layer between temperature and post weld heat treatment of carbon steel weldments generally no post-weld heat treatment, When welding higher stiffness, wall thicker and weld a long time, in order to avoid weld cracking tendency to increase in the welding process, should be take control layer between temperature and post weld heat treatment and other measures to eliminate stress. Such as mild steel pipe wall thickness is greater than 36mm, welded after heat treatment, tempering temperature of 600-650 °C.

Choose mild steel welding rod welding materials (electrodes) selection principle is to ensure the equal strength of welded joints and base metal. Tensile strength average 417.5N/mm2, the tensile strength of not less than while E43xx series of electrodes deposited metal 420N/mm2, exactly matching on the mechanical properties.