A high level of residual stress inside of the cast iron rolls is a result of the combination of the heat stress and structural stress. It might cause change in the roll shape and dimension during the machining. Some residual stress (for example, the high residual tensile stress at the core) will result in a negative impact on its application. Therefore, all the cast iron rolls must undergo annealing treatment to release the stress. Some cast rolls even require for a normalization treatment.
According to the actual demand of roll production, we have been equipped with the domestically most advanced heat treatment furnace. The furnaces are equipped with electric radiation units and fans for enhanced circulation of the furnace atmosphere. The temperature and cycle times are capable of maintaining distribution and accuracy within 10 °C, so as to guarantee uniform hardness.