ç ¼Pipe fittings Weldability heat treatment effect

When the pump tubing is welded, proper preheat and interlayer temperature must be applied, otherwise cracking will occur. Preheating, interlaminar temperature, and welding heat will degrade the microstructure and mechanical properties of the heat-affected zone, so heat treatment after welding is required to restore the heat-affected zone to the desired properties. Carbon steel castings have been annealed before welding. Does not hinder welding, but makes welding easier. If you want to improve the performance of the welded joint after welding, you need to heat treatment.
In order to ensure that the heat-treated base metal before welding has a good welded joint, low-hydrogen welding materials must be used and low-hydrogen welding conditions must be ensured . The welding material of the crucible pump tube must be strictly dried before use. In general, the heat treated mild steel arc welding is not preheated, but should be preheated if the metal temperature is less than about 10°C. In addition, if the plate thickness is greater than 25.4mm or the joints are constrained, preheating should be performed. Preheating temperature ≥ 40°C. As the case may be, for medium-carbon structural steels, if the helium pump fittings require welding of heat-treated components, they must be welded. Take measures to prevent cracking.