GST Graphitic Supermit Alloy Steel Rolls
GST Supermit Alloy Steel is a high alloy steel, manufactured by means of a special multi-stage heat treatment in order to develop the combination of hardness, toughness and wear resistance required for a variety of heavy duty applications. The structure produced consists of well broken up and dispersed carbides in a matrix of bainite and pearlite. Up to Carbon levels of %1.55, there is an amount of discontinuous carbide, but most of the hardness and wear resistance is imparted by the highly alloyed matrix. Above this level, free carbides provide additional wear resistance where required. Because of their high hardenability, GST Supermit Alloy Steel shows no fall off in hardness with increasing depth.
The carbide content and tough, hard matrix makes GST Supermit Alloy Steel particularly suitable for section rolling. Resistance to abrasive wear is high and surface finish remains very good for the duration of each mounting as metallographic structure is consistent until discard. Experience in many mills has shown that GST Supermit Alloy Steel gives substantially higher outputs than conventional materials.
GST is suitable for two high stands with high bending forces. There is excellent resistance to thermal fatigue, especially in the lower %C grades, and thus is very suitable as roughing rolls in many applications.
GST Graphitic Supermit Alloy Steel rolls are supplied with a controlled amount of well dispersed graphite in their microstructure. This flake graphite promotes a finer and more controlled fire-crack pattern. GST is recommended when adverse thermal conditions are likely to be met - free graphite reduces the impact of thermal shocks by means of improved dissipation of heat from the surface to the core during the heating cycle and from the core to the surface during the cooling cycle of the roll.