Apparatus for continuously annealing metal strip and hearth roll therefor.

摘要

An improved layout of the hearth rolls in an annealing furnace comprises a plurality of ceramic coated rolls and a plated rolls. The ceramic coated rolls are arranged in a region in the annealing furnace where the temperature is higher than or equal to 450 DEG C. On the other hand, the plated rolls are arranged in a region where the temperature is lower than 450 DEG C. The hearth roll is provided a wear resistant coating of chrome plate or sprayed on ceramic of a thickness greater than or equal to 1 mu m and less than or equal to 100 mu m. In addition, according to the invention, the hearth roll is provided a surface roughness Ra in the range of 4.5 mu m to 20 mu m.