Roll for hot rolling
A roll for hot-rolling includes a body, wherein at least a part of an envelope surface of the body is made of a high speed steel that with reference to its chemical composition consists of the following elements, in weight %: 1-3 Carbon (C), 3-6 Chromium (Cr), 4.5-7 Molybdenum (Mo), 6-15 Tungsten (W), 3-14 Vanadium (V), 0-10 Cobalt (Co), 0-3 Niobium (Nb), 0-0.5 Nitrogen (N), 0.4-1 Yttrium (Y), eventualy distributed in the powder, and remainder iron (Fe) and unavoidable impurities, wherein contents of molybdenum (Mo) and tungsten (W) satisfy the formula Mo+0.5W=2.0-10.0 weight %.
1. A roll for hot-rolling comprising a body, wherein at least a part of an envelope surface of said body is made of a high speed steel by consolidation of a powder that with reference to its chemical composition consists of the following elements, in weight %:
1.0-3.0 Carbon (C);
3.0-6.0 Chromium (Cr);
4.5-7.0 Molybdenum (Mo);
6.0-15.0 Tungsten (W);
3.0-14.0 Vanadium (V);
0-10.0 Cobalt (Co);
0-3.0 Niobium (Nb);
0-0.5 Nitrogen (N);
0.4-1.0 Yttrium (Y), evenly distributed in the powder; and
remainder iron (Fe) and unavoidable impurities, wherein contents of molybdenum (Mo) and tungsten (W) satisfy the formula Mo+0.5W=2.0-10.0 weight %,
wherein the Yttrium (Y) evenly distributed in the powder comprises an oxide scale adhering to the high speed steel.
2. A roll for hot-rolling according to claim 1 , wherein said body includes an axially extending core, and an axially extending sleeve arranged radially outside said core.
3. A roll for hot-rolling according to claim 2 , wherein said sleeve is made of said high speed steel.
4. A roll for hot-rolling according to claim 2 , wherein said sleeve is made of a consolidation of a powder of said high speed steel, which powder is subjected to elevated heat and elevated pressure causing consolidation.
5. A roll for hot-rolling according to claim 2 , wherein said core is made of cast steel or cast iron or forged steel.
6. A roll for hot-rolling according to claims 2 , wherein a material of said sleeve has carbide particles that have a mean carbide particle size<3.0 μm.
7. A roll for hot-rolling according to claim 2 , wherein the sleeve has an isotropic microstructure.
8. A roll for hot-rolling according to claim 2 , wherein said sleeve is shrink fit on said core.
9. A roll for hot-rolling according to claim 1 , wherein the yttrium (Y) content of said high speed steel is less than 0.6 weight %.
10. A roll for hot-rolling according to claim 1 , wherein the yttrium (Y) content of said high speed steel is in the range 0.45-0.60 weight %.
11. A roll for hot-rolling according to claim 1 , wherein contents of moludbenum (Mo) and tungsten (W) are based on weight % and satisfy formula Mo+0.5W=5.0-8.5 weight %.
12. A roll for hot-rolling according to claim 1 , wherein the carbon (C) content of said high speed steel is in the range of from 1.1-1.4 weight %.
13. A roll for hot-rolling according to claim 1 , wherein the chromium (Cr) content of said high speed steel is in the range of from 4.0-5.0 weight %.
14. A roll for hot-rolling according to claim 1 , wherein the Molybdenum (Mo) content of said high speed steel is in the range of from 4.5-5.5 weight %.
15. A roll for hot-rolling according to claim 1 , wherein the tungsten (W) content of said high speed steel is in the range of from 6.0-7.0 weight %.
16. A roll for hot-rolling according to claim 1 , wherein the Vanadium (V) content of said high speed steel is in the range of from 3.0-5.0 weight %.
17. The roll for hot-rolling according to claim 1 , wherein the oxide scale adhering to the high speed steel is at a saturation thickness.