Non Continuous Carbide Rolls (NCC)
Rolls for rough stand mills require a combination of some properties, some of which can be counteracted by the others. These properties include wearability, resistance of fire cracking and impact, hot hardness and hot strengh etc. Excessive network carbides will improve wearability and impact resistance but dramatically reduce fracture toughness. Under rough rolling process they can promote fire cracking formation and added to form Bainitic/Martensitec(acicular) matrix, which is more wearable than conventional pearlitic matrix. The Molybdenum can also improve the hot hardness of rolls.
This type of roll is manufactured from high alloy materials with special heat treatment. Carbide content in the matrix is less than 5%, which is satisfactory to the requirement of rough stand mill.
Table.1 Chemical Composition %
|NCCⅠ||40-50||≥520||970-1380||￠500-1380||1000-35000||Roughing stands of bar and wire mills, BD2 rolls for large section|