This roll quality was developed for applications where good surface finish as well as a high resistance to breakage are required.

Tungsten is added to the rolls to refine the grain and to increase the hot strength of the steel. It also produces harder carbides which give the rolls improved wear properties.

The rolls are normally air hardened and tempered to produce a tough, hard structure which in the higher carbon grades consists of well dispersed free carbide in a matrix of very fine pearlite. The amount of carbide and thus the wear resistance increases with the carbon content.