Is preheating required for welding during winter construction?
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Is preheating required for welding during winter construction? Why is preheating necessary? Will pores or cracks occur if it isn’t preheated? Under what conditions, and at what temperature threshold, is preheating necessary? Should the base material or the welding electrode be preheated? What equipment should be used for preheating, and to what temperature, e.g., 15°C? What do the specifications require? At what air humidity level should the base material and welding electrodes be dried? When we use an argon arc welding gun and copper-coated welding wire to weld seamless steel pipes, is drying not required?
In winter welding, preheating before welding and heat retention after welding are necessary; otherwise, due to the low temperatures, the weld seam may cool down too quickly and crack.
GB/T 150 and NB/T 47015 require that below 0°C, it should be preheated to a temperature above the touchable temperature (15°C).
Not preheating first leads to the formation of pores, and materials with high structural constraint and crack sensitivity are more prone to cracking. Preheat the base material.