Heating process of Q235NH steel

Since the Cu element is easily enriched at the crystal boundary, it will cause thermal brittleness during hot processing, forming network cracks on the surface of the Q235NH steel plate. In order to reduce the thermal embrittlement effect of Cu element, a high-temperature, fast-burning heating system is adopted, and the atmosphere in the furnace is controlled to be a reducing or weakly oxidizing atmosphere. On the premise of ensuring the heating quality of the Q235NH steel billet, the heating time of the steel billet in the heating furnace is shortened. The heating time is ≤2.5h to reduce the formation of iron oxide scale on the surface of the billet.

The exit temperature of Q235NH steel billet is controlled at 1120-1180℃ to ensure uniform heating of the billet.