Iron-based alloy for internal combustion engine valve seat inserts and the like
View Patent ↗An iron-based corrosion resistant and wear resistant alloy is addressed. The alloy contains (in weight percent) 1.1-1.4% carbon, 11-14.25% chromium, 4.75-6.25% molybdenum, 3.5-4.5% tungsten, 0-3% cobalt, 1.5-2.5% niobium, 1-1.75% vanadium, 0-2.5% copper, up to 1.0% silicon, up to 0.8% nickel, up to 0.6% manganese, and the balance iron. The alloy is suitable for use in valve seat insert applications.
1. An iron-based alloy comprising, in weight percentage:
carbon in an amount effective to inhibit formation of primary carbides;
chromium from about 11 to about 14.25;
molybdenum from about 4.75 to about 6.25;
tungsten from about 3.5 to about 4.5;
cobalt from 0 to about 3;
niobium from about 1.5 to about 2.5;
vanadium from about 1 to about 1.75;
copper from 0 to about 2.5;
silicon up to about 1;
nickel up to about 0.8;
manganese up to about 0.6; and
iron from about 61 to about 77.15.
2. The alloy of claim 1 , wherein the alloy comprises at least about 1.15 to about 1.35 weight percent carbon.
3. The alloy of claim 1 , wherein the alloy comprises at least about 11.5 weight percent chromium.
4. The alloy of claim 1 , wherein the alloy comprises at most about 14 weight percent chromium.
5. The alloy of claim 1 wherein the alloy comprises from about 1.5 to about 2.5 weight percent cobalt.
6. The alloy of claim 1 wherein the alloy comprises about 2 weight percent copper or about 2 weight percent cobalt.
7. The iron-based alloy of claim 1 wherein the alloy comprises:
Element
Weight Percent
Chromium
12.75-13.5
Molybdenum
5-6
Tungsten
3.75-4.5
Cobalt
1.5-2.5
Niobium
1.75-2.5
Vanadium
1.15-1.75
Copper
0-2.5
Silicon
up to 1
Nickel
up to 0.8
Manganese
up to 0.6
Iron
balance.
8. The alloy of claim 1 , wherein the alloy includes 0 weight percent boron.
9. The alloy of claim 1 comprising:
about 0.6 weight percent silicon;
about 13.15 weight percent chromium;
about 5.75 weight percent molybdenum;
about 4.0 weight percent tungsten;
about 2.05 weight percent cobalt;
about 1.25 weight percent vanadium;
about 2.05 weight percent niobium;
about 0.3 weight percent manganese;
about 0.55 weight percent nickel; and
about 69.05 weight percent iron.
10. The alloy of claim 1 , wherein said alloy is manufactured by casting.
11. The alloy of claim 7 , wherein said alloy is manufactured by casting.
12. A valve seat insert made of the alloy of claim 1 .
13. A valve seat insert made of alloy of claim 7 .
14. A valve seat insert of an internal combustion engine, said valve seat insert made of an alloy comprising, in weight percentage:
carbon in an amount effective to inhibit formation of primary carbides;
chromium from about 11 to about 14.25;
molybdenum from about 4.75 to about 6.25;
tungsten from about 3.5 to about 4.5;
cobalt from 0 to about 3;
niobium from about 1.5 to about 2.5;
vanadium from about 1 to about 1.75;
copper from 0 to about 2.5;
silicon up to about 1;
nickel up to about 0.8;
manganese up to about 0.6; and
iron from about 61 to about 77.15.
15. The valve seat insert of claim 14 , wherein said alloy is manufactured by casting.
16. A cast, iron-based alloy comprising, in weight percentage:
carbon in an amount effective to inhibit formation of primary carbides;
chromium from about 11 to about 14.25;
molybdenum from about 4.75 to about 6.25;
nickel up to about 0.8;
tungsten from about 3.5 to about 4.5; and
the balance, iron, other alloying elements and incidental impurities.
17. A valve seat insert made of the alloy of claim 16 .
18. The alloy of claim 16 further comprising from about 1.5 to about 2.5 weight percent niobium.
19. The alloy of claim 16 wherein the alloy further comprises about 2 weight percent copper or about 2 weight percent cobalt.
20. An iron-based alloy having carbon in an amount effective to inhibit formation of primary carbides, the alloy further comprising:
Element
Weight Percent
Chromium
12.75-14.15
Molybdenum
5.25-6.15
Tungsten
3.75-4.55
Cobalt
1.95-2.45
Niobium
1.75-2.55
Vanadium
1.15-1.75
Copper
0-2
Silicon
up to 1
Nickel
up to 0.8
Manganese
up to 0.6
Boron
0-1
Iron
balance.
21. The alloy of claim 1 , wherein the alloy comprises an equiaxed microstructure with secondary carbides.
22. The valve seat of claim 14 , wherein the alloy comprises an equiaxed microstructure with secondary carbides.
23. The cast, iron-based alloy of claim 16 , wherein the alloy comprises an equiaxed microstructure with secondary carbides.
24. The alloy of claim 1 , wherein the alloy has a fine-grained martensitic tool steel microstructure.
25. The valve seat of claim 14 , wherein the alloy has a fine-grained martensitic tool steel microstructure.
26. The cast, iron-based alloy of claim 16 , wherein the alloy has a fine-grained martensitic tool steel microstructure.