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Graphtic Steel Base
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Graphitic Steel Base is similar to normal Steel Base in that it is a hypereutectoid steel with a carbon content between 1.2% and 2.4%. However, unlike Steel Base, all the carbon is not present as carbide. Modifications of the alloy content and metal treatment produces a controlled amount of fine graphite particles dispersed throughout the structure.
The presence of the graphite improves the firecrack resistance of the roll material and reduces thrust collar wear as well as the side wear which occurs during indirect reduction. It also helps to resist wear in applications with aggressive abrasion on side faces due to excessive speed mismatch.
The grade chosen for a particular application will have sufficient carbide in the microstructure to ensure that the wear resistance is high while the matrix structure can be either spheroidised or lamellar pearlite depending upon the heat treatment given.
The virtually constant hardness and wear resistance across the barrel diameter allows Graphitic Steel Base rolls to be used for almost any size of section, especially where fire cracking is a problem.
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Applications
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| Product |
Type of Mill |
Position |
| Billet |
2 High Continuous |
Roughing & Inbtermediary |
| Heavy Section & Rail |
2 & 3 High |
All Positions |
| Beams |
Universal |
All Positions |
| Medium Section |
2 & 3 High |
All Positions |
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Typical Mechanical Properties
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N/mm2 |
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| Property |
Low Carbon |
High Carbon |
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Typical Hardness Gradient
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Micrograph x 100
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Typical Analysis
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| Code |
Leeb E |
Shore C |
C |
Si |
Mn |
Ni |
Cr |
Mo |
| GS7 |
525-590 |
40-50 |
1.2/1.4 |
1.0/2.0 |
0.5/0.9 |
0.2/0.8 |
0.6/1.2 |
0.25max. |
| GS8 |
540-590 |
42-50 |
1.4/1.6 |
1.0/2.0 |
0.5/0.9 |
0.2/0.8 |
0.6/1.2 |
0.25max. |
| GS9 |
550-600 |
44-52 |
1.6/1.8 |
1.0/2.0 |
0.5/0.9 |
0.2/0.8 |
0.6/1.2 |
0.25max. |
| GS10 |
550-600 |
44-52 |
1.8/2.0 |
1.0/2.0 |
0.5/0.9 |
0.2/0.8 |
0.6/1.2 |
0.25max. |
| GS11 |
555-610 |
45-53 |
2.0/2.2 |
1.0/2.0 |
0.5/0.9 |
0.2/0.8 |
0.6/1.2 |
0.25max. |
| GS12 |
555-610 |
45-53 |
2.2/2.4 |
1.0/2.0 |
0.5/0.9 |
0.2/0.8 |
0.6/1.2 |
0.25max. |
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