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PM high speed steel rolls SARAMET

The rolls made of the powdermetallurgically produced high speed steel SARAMET provide an alternative for rolling speeds from 0.2-20 m/sec in intermediate stands as well as for critical applications like slit, angle and special profile rolling.
The homogeneous structure of the 1-5 ㎛ sized spheroidal and hard carbides results in excellent performances. The microstructure is essential to guarantee a high wear resistance and a high toughness at the same time.

Manufacturing

The gas-atomised powders of the alloys below are compacted to parts without any porosity and with an ideal carbide distribusion, using the HIP process at a temperature of 1100-1200℃ Celsius and a pressure between 1000 to 1200 bar. The steel can is then machined off, the SARAMET rolls are hardened and tempered to 50-62 HRC and finish machined or ground.

	C	W	Cr	V	Mo	Co
SARAMET 4	1.3 %	5.5 %	4.5 %	4 %	4.5 %	-
SARAMET 9	1.8 %	-	5.2 %	9 %	1.5 %	-
SARAMET 10	2.4 %	-	5.2 %	10 %	1.5 %	-
SARAMET 15	1.6 %	12.5 %	4.0 %	5 %	0.5 %	5 %
SARAMET Cr	2.2 %	-	18.0 %	6 %	-	-

Applications

The high carbide content of SARAMET roll rings combined with the hardness of 50-62 HRC results in a high wear resistance. The spheroidal shape and the homogeneous distribution of the 1-5㎛ sized carbides confer a relatively high toughness to this material. These are the reasons for the success in hot rolling with speed ranges from 0.2-20 m/sec in intermediate stands and for special profile rolls.

Cooling

The hardness of 50-62 HRC and the thermal stress on the rolls require efficient cooling immediately after the contact with the hot roll stock. The layout of the cooling pipes as well as the colling parameters should meet the requirements which are applied when using tungsten carbides.

Machining

The machining of the PM-HSS rolls SARAMET is done by copy turning with ceramic or CBN turning tools or by grinding with CBN wheels. Depending on the roll stock, the rolling conditions and the rolled tonnages redressing the diameter by 0.5-2.0mm may become necessary.