A special heat treatment known as the "SIP" or the "Sumitomo Improvement Penetration" arranges the upper layer constituents of the roll surface in a precise manner, which not only improves the mass effect but also raises the overall strength and dramatically improves the bending durability. This is a roll with significant improvement of surface roughness resistance and thermal crack.

An example of mechanical characteristics

	N treatment	SIP treatment
Hardness (HS)	45±3	45/50
Tension (kg/mm2)	64	74
Bearing force (kg/mm2)	49	58
Elongation (%)	3.5	3.1
Impact value (kg/cm)	0.9	1.6
Fatigue strength (kg/mm2)	19	24
Fracture toughness value (KIc)	185	203

Hardness distribution

These are rolls that have properties that are in between the high speed tool steel materials and the conventional materials such as cast iron materials (ductile cast iron) and cast steel materials (adamite). These are rolls with material characteristics that appear to contradict each other, such as thermal crack resistance, toughness, wear resistance and surface roughness resistance, making it capable of responding to a variety of quality requirements as a raw material and through the entire process leading up to the finishing stand.

Image diagram of materials

Friction test result

These products have better wear resistance and roughening resistance than soluble (casting) high speed tool steel rolls, and they are used as high-quality roll materials.

Positioning of Powdered High Speed Tool Steel

To each stand, we apply the manufacturing know-how of Osprey High Speed Tool Steel rolls (spray casting method: rapidly cooling and solidifying process in the Osp method) that we have manufactured previously. It is used for bar steel, wire rods, medium rolls for flat steel and rolls for finishing.