Original preheating temperature: the temperature of the workpiece in the weld zone immediately prior to any welding operation.
初始预热温度是指任何焊接操作开始之前，焊接区域内工件的瞬时温度。
2
For example, substantial preheating is necessary before weld overlaying.
例如，大量的预热是必要的焊缝覆盖前。
3
Aiming at the zinc residue in the weld joint nugget of DP590GA, a double-impulse welding parameter with preheating impulse is designed to further improve its mechanical properties of the weld joint.