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Standard Alloy Indefinite Chill
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Double Pour, Flake or Nodular Core
Higher hardness indefinite chill rolls must be double poured to maintain the desired level of toughness and thermal properties in the journals and barrel axis. The increased hardness is obtained by alloy additions - mainly nickel, chromium and molybdenum - which modify the matrix structure to produce harder acicular phases.
These rolls combine first class wear resistance and surface finish with the very good spall and firecrack resistance which results from their graphite content and they have proved to be very successful in hot wide strip mills. They also give excellent results under variable operating conditions in plate mills.
The core material can be either flake or nodular iron according to requirements. In general, the flake core will display better thermal properties while the nodular iron achieves greater mechanical strength. The extra strength has become increasingly important in mills using work roll bending and shifting systems. Rolls can be static cast or vertical centrifugal cast.
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Applications
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| Product |
Type of Mill |
Position |
| Plate |
2, 3 and 4 High |
Roughing/Finishing |
| Wide Strip |
4 High Continuous |
Finishing |
| Wide Strip |
4 High Reversing |
Roughing/Finishing |
| Cold Reduced Strip |
4 High Continuous |
Work Rolls |
| Sheet and Coil |
2 High Skin Pass |
Work Rolls |
| Sheet and Coil |
4 High Temper |
Back Up Rolls |
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Typical Mechanical Properties
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Barrel |
Journal & Axis |
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| Property |
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Flake Core |
Nodular Core |
| Tensile Strength |
345 |
235 |
425 |
| Bending Strength |
540 |
345 |
835 |
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Typical Hardness Gradient
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Micrograph
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Shell x 100
Flake Core x 50 Nodular Core x 50
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Typical Analysis
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| Code |
Leeb E |
Shore C |
C |
Si |
Mn |
Ni |
Cr |
Mo |
| DX6 |
680-710 |
65-70 |
3.0/3.4 |
0.7/1.2 |
0.8/1.5 |
3.0/4.0 |
1.0/1.5 |
0.1/0.4 |
| DX7 |
710-740 |
70-75 |
3.0/3.4 |
0.7/1.0 |
0.3/1.5 |
3.5/5.0 |
1.0/2.0 |
0.1/0.4 |
| DX9 |
740-795 |
75-85 |
3.0/3.5 |
0.6/1.0 |
0.3/1.5 |
4.0/5.0 |
1.2/2.0 |
0.2/0.5 |
| RX7 |
670-740 |
63-75 |
3.0/3.4 |
0.7/1.2 |
0.3/1.5 |
3.5/4.5 |
1.0/2.0 |
0.1/0.4 |
| RX8 |
710-750 |
70-77 |
3.0/3.4 |
0.7/1.2 |
0.3/1.5 |
3.8/4.8 |
1.0/2.0 |
0.1/0.4 |
| RX9 |
740-780 |
75-82 |
3.0/3.4 |
0.7/1.2 |
0.3/1.5 |
4.0/5.0 |
1.0/2.0 |
0.1/0.4 |
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