Hisar Celik Döküm Sanayi ve Ticaret A.S.

MaterialsSG-X Ferritic SG-X Ni Ferritic SG-PC SG-AC AIC Hi-Cr SG-PC Cr SG-AC Cr ACS GST GSB GST-GT
Tools Production Process



SG-X Extra Ferritic Nodular Iron Rolls
 

Description
SG-X Extra Ferritic nodular iron material further develops properties associated with SG Pearlitic Chill qualities. Typically, the graphite nodules are surrounded by a layer of ferrite giving a characteristic “bull's eye” effect.

The structure of the matrix ranges from mostly pearlitic in the lower alloyed grades and transitions to bainitic in the higher alloyed and heat treated grades. In all grades, a significant amount of ferrite surrounds each graphite nodule and carbide formation is suppressed.

It is not an exaggeration to state that this material was developed to provide extreme resistance to fire-cracking as well as thermal failure and has exceptional mechanical properties. This material is fine-tuned by precise control of alloying elements and is subjected to a high temperature multi-stage heat treatment.

The high strength and thermal resistance of SG-X Ferritic make it an ideal roll material for use in Breakdown and Roughing applications where thermal duty is severe.

The rolls have virtually no hardness drop and hardness penetration is excellent, permitting SG-X Ferritic to be used in all types of pass profiles. The softer grades have an excellent resistance to fire-cracking and are Hisar’s most fire-crack resistant cast roll grades.

Because of the nodular form of the graphite, the strength of SG-X Ferritic is quite high and the rolls can be used in relatively heavy duty applications.

All rolls of this material are statically single poured.

SG-PC Pearlitic Chill rolls are essentially an indefinite chill type materıal, but with the graphite in nodular form instead of flake. The name of this material is based on its constituents of nodular graphite and carbides in a pearlitic matrix. The internal ‘notch effect’ of nodular graphite is relatively small and therefore SG-PC Pearlitic Chill rolls have a much higher strength and allow the use of an iron roll in applications which would represent too high a duty for a flake iron quality. Due to its hardness penetration, good wear resistance and tough necks, this material has become a benchmark in the rolling of long products and is suitable for a wide range of applications.

The softer grades have a pearlitic matrix containing ferrite around the graphite nodules, the intermediate hardness grades have a completely pearlitic matrix, while the hardest grades have a pearlitic-bainitic matrix. The carbide content is considerably higher in the harder grades than in the softer ones. The resistance to fire-cracking is best when the softer grades are used.

The indefinite chill characteristics give SG-PC Pearlitic Chill rolls good hardness penetration so that they are suitable for small to medium sections and billets although they can also give good results when rolling flat products.

All rolls of this material are statically single poured.

The barrel structure of AIC Alloy Indefinite Chill Iron rolls is not as that of a clear chill Iron which is a white Iron, but rather a gradual transition from a carbide rich structure containing a small amount of fine flake graphite at the surface to a gray core material. The barrel surface is in an intermediate state between white and gray iron. Part of the carbon forms flake graphite and the remainder forms carbides. The amount of graphite is less prominent in higher hardness grades and increases towards the centre of the roll. Thus, a hardness gradient is developed between the core and the shell. The depth of the chilled layer is difficult to define and the hardness decreases gradually towards the centre of the roll.

In softer grades, AIC Alloy Indefinite Chill Iron have a structure consisting of more flake graphite with few carbides in a pearlitic matrix. Harder grades have a bainitic-martensitic matrix with an increased amount of carbides.

Due to alloy additions, hardness penetration is better than that of a clear chill roll and this material may be used in applications with deeper groves such as small and medium section rolling and also for finishing billets.

The presence of flake graphite improves spalling resistance and also enhances resistance to fire-cracking. All of these properties combined with the excellent surface finish make AIC Alloy Indefinite Chill Iron very suitable for rolling flats, sections and similar products where surface finish is critical.

All rolls of this material are statically single poured.