Blade made of steel alloy
View Patent ↗A refiner or disperser blade is made of a steel alloy by casting. The alloy comprises, in weight percent: 0.6 to 4 wt-% carbon (C), 0.5 to 1.5 wt-% silicon (Si), 0.4 to 1.5 wt-% manganese (Mn), 12 to 28 wt-% chromium (Cr), 4 to 12 wt-% niobium (Nb), as well as iron (Fe).
1. A refiner or disperser blade made of a steel alloy by casting, wherein the composition of the steel alloy comprises, in weight percent:
0.6 to 4 wt-% carbon (C), 0.5 to 1.5 wt-% silicon (Si), 0.4 to 1.5 wt-% manganese (Mn), 12 to 28 wt-% chromium (Cr), 4 to 12 wt-% niobium (Nb), as well as iron (Fe), whereby niobium carbides settle in the blade evenly in such a manner that does not weaken the ductility of the blade.
2. The blade of claim 1 wherein the steel alloy has a ratio of chromium/carbon of at least 7.
3. The blade of claim 1 wherein the steel alloy comprises nickel (Ni) not more than 2.5 wt-%.
4. The blade of claim 3 wherein the steel alloy comprises nickel at least 0.5 wt-%.
5. The blade of claim 3 wherein the steel alloy comprises nickel at least 1.0 wt-%.
6. The blade of claim 3 wherein the steel alloy comprises nickel not more than 2.2 wt-%.
7. The blade of claim 3 wherein the steel alloy comprises nickel not more than 2.0 wt-%.
8. The blade of claim 1 wherein the steel alloy comprises not more than 2.0 wt-% of molybdenum (Mo).
9. The blade of claim 8 wherein the steel alloy comprises molybdenum at least 0.2 wt-%.
10. The blade of claim 8 wherein the steel alloy comprises molybdenum at least 0.3 wt-%.
11. The blade of claim 8 wherein the steel alloy comprises molybdenum not more than 1.5 wt-%.
12. The blade of claim 8 wherein the steel alloy comprises molybdenum not more than 0.9 wt-%.
13. The blade of claim 1 wherein the steel alloy comprises 2.6 to 3.2 wt-% carbon, 0.7 to 1.3 wt-% silicon, 0.5 to 1.1 wt-% manganese, 21 to 25 wt-% chromium, 0.0 to 1.0 wt-% molybdenum, 4 to 6 wt-% niobium, the rest being iron and impurities.
14. The blade of claim 1 wherein the steel alloy comprises 1.8 to 2.4 wt-% carbon, 0.5 to 1.1 wt-% silicon, 0.4 to 1.0 wt-% manganese, 15 to 19 wt-% chromium, 1.2 to 1.8 wt-% nickel, 0.0 to 1.0 wt-% molybdenum, 4 to 7 wt-% niobium, the rest being iron and impurities.
15. The blade of claim 1 wherein the steel alloy comprises 1.0 to 1.6 wt-% carbon, 0.5 to 1.1 wt-% silicon, 0.4 to 1.0 wt-% manganese, 13 to 17 wt-% chromium, 1.2 to 1.8 wt-% nickel, 0.3 to 1.0 wt-% molybdenum, 5 to 8 wt-% niobium, the rest being iron and impurities.
16. The blade of claim 1 wherein the steel alloy comprises carbon at least 0.8 wt-%.
17. The blade of claim 1 wherein the steel alloy comprises carbon at least 1.0 wt-%.
18. The blade of claim 1 wherein the steel alloy comprises carbon not more than 3.5 wt-%.
19. The blade of claim 1 wherein the steel alloy comprises carbon not more than 3.2 wt-%.
20. The blade of claim 1 wherein the steel alloy comprises silicon at least 0.8 wt-%.
21. The blade of claim 1 wherein the steel alloy comprises silicon not more than 1.0 wt-%.
22. The blade of claim 1 wherein the steel alloy comprises manganese at least 0.7 wt-%.
23. The blade of claim 1 wherein the steel alloy comprises manganese not more than 0.8 wt-%.
24. The blade of claim 1 wherein the steel alloy comprises chromium at least 13 wt-%.
25. The blade of claim 1 wherein the steel alloy comprises chromium at least 14 wt-%.
26. The blade of claim 1 wherein the steel alloy comprises chromium not more than 26 wt-%.
27. The blade of claim 1 wherein the steel alloy comprises chromium not more than 24 wt-%.
28. The blade of claim 1 wherein the steel alloy contains niobium at least 4.5 wt-%.
29. The blade of claim 1 wherein the steel alloy comprises niobium at least 5.0 wt-%.
30. The blade of claim 1 wherein the steel alloy comprises niobium not more than 10 wt-%.
31. The blade of claim 1 wherein the steel alloy comprises niobium not more than 8 wt-%.
32. A mechanical pulp refiner, low consistency refiner, fiberboard refiner, or disperser comprising:
at least two rotationally symmetrical cast pieces, with the shape of a plate, cylinder or cone or combinations of these shapes placed against each other;
wherein the at least two rotationally symmetrical cast pieces are formed of a cast steel alloy which uses niobium to form niobium carbides in a martensitic structure of the steel alloy so that abrasion resistance of the two rotationally symmetrical cast pieces is improved without decreasing the cast pieces impact ductility;
wherein the cast steel alloy comprises, in weight percent:
0.6 to 4 wt-% carbon (C), 0.5 to 1.5 wt-% silicon (Si), 0.4 to 1.5 wt-% manganese (Mn), 12 to 28 wt-% chromium (Cr), 4 to 12 wt-% niobium (Nb), as well as iron (Fe), and wherein niobium carbides settle in the two rotationally symmetrical cast pieces evenly in such a manner that does not weaken the ductility of the two rotationally symmetrical cast pieces.
33. A mechanical pulp refiner, low consistency refiner, fiberboard refiner, or disperser comprising:
at least two rotationally symmetrical cast pieces, with the shape of a plate, cylinder or cone or combinations of these shapes placed against each other;
wherein the at least two rotationally symmetrical cast pieces are formed of a cast steel alloy which uses niobium to form niobium carbides in a martensitic structure of the steel alloy so that abrasion resistance of the two rotationally symmetrical cast pieces is improved without decreasing the cast pieces impact ductility;
wherein the cast steel alloy consists essentially of, in weight percent:
0.6 to 4 wt-% carbon (C), 0.5 to 1.5 wt-% silicon (Si), 0.4 to 1.5 wt-% manganese (Mn), 12 to 28 wt-% chromium (Cr), 4 to 12 wt-% niobium (Nb), nickel (Ni) not more than 2.5 wt-%, molybdenum (Mo) not more than 2.0 wt-% and iron (Fe); and
wherein a ratio of chromium/carbon of at least 7 is maintained, and wherein niobium carbides settle in the two rotationally symmetrical cast pieces evenly in such a manner that does not weaken the ductility of the two rotationally symmetrical cast pieces.