Cast Iron With Improved High Temperature Properties
A nodular, compacted graphite or other hybrid or duplex graphite morphology cast high silicon iron is disclosed which contains up to 1.5% tungsten, up to 0.8% vanadium, and up to 1.2% niobium; and at least 60.0% iron, all percentages are based on the total weight of the composition. This cast iron exhibits high strength and good ductility over a wide temperature range compared to the conventional SiMo ductile iron. The compositions may further contain, up to 1.5% molybdenum and up to 1.0% chromium to offer improvements in material strength. The compositions may include 0.2 to 0.5% by weight aluminum and up to 1.2% chromium for further oxidation resistance and 0.5 to 5.0% nickel for corrosion resistance.
1 . A high silicon cast iron composition comprising:
greater than about 60 wt. % iron;
between about 2.8 to about 5.0 wt. % silicon;
from about 0.03 to about 1.5 wt. % tungsten;
up to about 0.8 wt. % vanadium; and
up to about 1.2% niobium.
2 . The cast iron composition of claim 1 , further comprising at least one constituent selected from the group consisting of molybdenum, chromium, nickel and carbon.
3 . The cast iron composition of claim 1 , wherein said vanadium is present in an amount of between about 0.02 to about 0.8 wt. %.
4 . The cast iron composition of claim 1 wherein said niobium is present in an amount of between about 0.02 to about 1.2 wt. %.
5 . The cast iron composition of claim 2 wherein said molybdenum is present in an amount up to about 1.5 wt. %.
6 . The cast iron composition of claim 2 wherein said aluminum is present in an amount of between about 0.2 and 3.0 wt. %.
7 . The cast iron composition of claim 2 wherein said nickel is present in an amount of between 0.5% and about 5.0 wt. %.
8 . The cast iron composition of claim 2 wherein carbon is present in an amount such that the wt. % carbon plus ⅓ the wt. % silicon is up to about 4.9 wt. %.
9 . Products formed from the cast iron composition of claim 1 .
10 . A molded article comprising a nodular, compacted graphite or hybrid or duplex graphite having a cast iron composition, wherein the cast iron composition comprises:
greater than about 80 wt. % iron;
between about 2.8 to about 5.0 wt. % silicon;
from about 0.03 to about 1.5 wt. % tungsten;
from about 0.2 to about 1.2 wt. % niobium; and
up to about 0.8 wt. % vanadium.
11 . The molded article of claim 10 wherein said vanadium is present in an amount of between about 0.02 to about 0.8 wt. %.
12 . The molded article of claim 11 further comprising between about 0.2 to about 1.5 wt. % molybdenum.
13 . The molded article of claim 11 further comprising between about 0.2 to about 3.0 wt. % aluminum.
14 . The molded article of claim 11 further comprising between about 0.5 to about 5.0 wt. % nickel.
15 . The molded article of claim 11 wherein carbon is present in an amount such that the wt. % carbon plus ⅓ the wt. % silicon is up to about 4.9 wt. %.
16 . The molded article of claim 10 wherein the article is an exhaust manifold.
17 . The molded article of claim 10 wherein the article is a turbocharger component.
18 . The molded article of claim 10 wherein the article is a catalytic converter housing.
19 . The molded article of claim 10 wherein the article is a fuel cell component.
20 . A high silicon cast iron composition comprising:
At least 60 wt. % iron;
between about 2.8 to about 5.0 wt. % silicon;
from about 0.2 to about 1.2 wt. % niobium;
up to about 1.5 wt. % tungsten;
up to about 0.8% vanadium; and.
at least one constituent selected from the group consisting of molybdenum, aluminum, nickel and carbon.
21 . The cast iron composition of claim 20 , wherein said vanadium is present in an amount of between about 0.02 to about 0.8 wt. %.
22 . The cast iron composition of claim 20 wherein said molybdenum is present in an amount up to about 1.5 wt. %.
23 . The cast iron composition of claim 20 wherein said tungsten is present in an amount of between about 0.003 to about 1.5 wt. %.
24 . The cast iron composition of claim 20 wherein said nickel is present in an amount of between 0.5% and about 5.0 wt. %.
25 . The cast iron composition of claim 20 wherein carbon is present in an amount such that the wt. % carbon plus ⅓ the wt. % silicon is up to about 4.9 wt. %.