Preheating shall be carried out for carbon and low alloy steel welding where required. Preheating temperature shall be kept uniform from the start to the end of welding.
在进行碳钢及低合金钢的焊接时应进行预热。预热温度在焊接开始到结束期间应保持均衡。
3
However, if outdoor temperature is comparatively low, the records preheating aren't required for the welding operation preheating to room temperature.