Since Q690D has good welding performance, it can be connected by a variety of welding processes. The following are commonly used Q690D welding processes:
1. Manual electric arc welding: Use low hydrogen type welding electrodes for welding, such as J507 or J607 electrodes. Welding should be preheating treatment before welding, preheating temperature of 150 ℃ ~ 250 ℃, welding process to maintain the interlayer temperature is not lower than the preheating temperature. After welding should be dehydrogenation treatment, that is, at about 200 ℃ to maintain more than 2 hours.
2. submerged arc welding: the use of low hydrogen submerged arc welding wire for welding, such as H13Mn2TiA or H13Mn2MoA wire. Welding should be preheating treatment before welding, preheating temperature of 150 ℃ ~ 250 ℃, welding process to maintain the interlayer temperature is not lower than the preheating temperature. After welding should be dehydrogenated, that is, at about 200 ℃ for more than 2 hours.
3. Gas-shielded welding: Use CO2 gas-shielded welding or mixed gas-shielded welding (Ar+CO2), and use low-hydrogen type welding wire such as H13Mn2MoA or H13Mn2TiA for welding. Preheating treatment should be carried out before welding, the preheating temperature is 150℃～250℃, and the interlayer temperature should be kept not lower than the preheating temperature during welding. After welding should be dehydrogenation treatment, that is, at about 200 ℃ to maintain more than 2 hours.
4. Resistance welding: spot welding or projection welding process for connection. Spot welding with a special electrode for operation, convex welding with a suitable bump as the connection point. Welding should be based on the actual situation to choose the appropriate current and electrode pressure for welding.
