Centrifugally cast grooved rolls with working layer of high-strength cast iron. Chemical composition, microstructure and properties.
The microstructure of grooved rolls (type СШХН and ТШХН) represented pearlite metal matrix in varying dispersive degrees depending on the nickel content, up until bainite at its maximum amount, eutectic cementite, the volumetric proportion of which varies depending on the desired hardness and execution of rolls and graphite inclusions in spherical shape. The high content of nickel and chromium allows to receive high-hardness and wear-resistant rolls along with a good set of strength characteristics.
Field of application of grooved rolls:
- Rolls of pre-finishing stands and finishing stands of wire mills, light-section mills, heavy-section mills, structural mills, pipe and tube mills; rolls of universal stands
- Rolls of breakdown and roughing stands of section mills
The metal microstructure of grooved rolls with nodular graphite.
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| Rolls structure with hardness 41-50 HS, х100 | Rolls structure with hardness 50-65 HS, х100 |
Table1. Chemical compound of metal of grooved rolls.
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Roll execution |
Chemical compound, % |
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|
С |
Si |
Mn |
P |
S |
Cr |
Ni |
Mo |
Cu |
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|
no more |
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СШХН(М) - 41-63 ТШХН(М) - 41-55 |
2,7-3,6 |
1,0-2,6 |
0,4-1,0 |
0,15 |
0,02 |
0,2-1,0 |
1,0-3,5 |
0,0-0,8 |
0,0-2,0 |
Table 2. Technological and physical-mechanical properties..
|
Roll execution |
Working layer depths, mm | Hardness, HS |
Bending strength, МPа |
Coefficient of elasticity, GPa | Impact strength, Joule/cm2 | Heat conductivity, W/m*К | Heat capacity, Joule /kg*К | Coefficient of linear extension (20?1000С) 106/°С |
|
СШХН(М) - 41-63 ТШХН(М) 41 - 55 |
- |
41-73 |
350-600 |
18-21 |
3,0-4,5 |
35-44 |
540-570 |
10-12 |
