::Gontermann peipers:Hi-Cr Steel Roll:

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16th September 2010

Gontermann to increase capacity

15th September 2010

Gontermann-Peipers seeks FMC nod for multi-commodity exchange

We have found GPIL to be an excellent choice for steels where chipping and cracking have not been a problem. It has worked well in applications on thinner ...

Hi-Cr Steel roll was developed for roughing stand & early finishing stand where the wear is basically ‘Thermo-Mechanical’ rather than abrasive in nature. The most important prevailing factor in Hi-Cr steel shell is the micro-hardness of the matrix which is governed by Chromium content of the matrix (Cr Matrix) or intern by (Cr/C) ratio with % Carbon content , ultimately result in increase in hardness, harden ability & oxidation

Chemical Composition Proximate Chemical Composition [ in %- wt ]

Hi Cr Steel	Element	%C	%Si	%Mn	%P	%S	%Cr	%Ni	%Mo	% V
	Min	1.00	0.4	0.70	0.06	0.03	8.0	0.80	1.00	0.00
	Max	2.3	0.8	1.20	max	max	15	1.50	2.5	0.30

Mechanical properties Mechanical Properties [1 MPa = 1 N/mm² (=0.1 kgf / mm² ) ]

Hi Cr Steel	Element	Tensile Strength of Journal (MPa)	Bending Strength of Journal (MPa)	Barrel Hardness in ShC
	min	300	450	65
	max	500	750	85

Hardness in Depth [SH C]

Physical properties Physical properties

physical properties

Excellent resistance to peeling of oxide layer -- To get resistant to sticking
Better Thermal conductivity (due to lower Chromium content than Hi-Cr Iron rolls) --To give resistance to thermo-mechanical cracking. Lesser slippage problem due to lower carbide content
Excellent resistance to oxidative wear due to higher Chromium partitioning towards matrix -- To give lesser wear resulting higher campaign life.
Excellent toughness due to lower carbon content - To resist crack initiation under fatigue loading conditions

Quality	Barrel Dia (mm)	Barrel Length (mm)	Total Length (mm)	Weight
Hi-Cr Steel	1200 (max)	3000 (max)	8000 (max)	25.0 MT

Hi-Cr Steel Rolls are used as Work Rolls for Roughing Stands of Hot Strip Tandem Mill & Reversing Mill where the strip temperature is the highest. New generation Hi-Cr Steel Rolls are also used as Work Rolls for early finishing stands (F1 and F2) of Hot Strip Mills