Acid resistant austenitic alloy for valve seat inserts
AssigneeWinsert, Inc.
InventorXuecheng Liang
Life of this patent
Estimating the term…
Abstract
A high-carbon austenitic iron-base alloy with good corrosion and wear resistance, particularly useful for valve seat insert applications when corrosion resistance is required, comprises about 1.8-3.5 wt % carbon, about 12-24 wt % chromium, about 0.5-4 wt % silicon, about 12-25 wt % nickel, about 2-12 wt % molybdenum and tungsten combined, about 0.05-4 wt % niobium and vanadium combined, about 0-1 wt % titanium, about 0.01-0.2 wt % aluminum, about 0.05-3 wt % copper, and less than 1.5 wt % manganese, with the balance being iron and a small amount of impurities.
Claims20
A homogeneous austenitic iron-base alloy with good corrosion and wear resistance, comprising:
- a) about 1.8 to about 3.5 wt % carbon;
- b) about 12 to about 24 wt % chromium;
- c) about 0.5 to about 4 wt % silicon;
- d) about 12 to about 25 wt % nickel;
- e) about 2 to about 16 wt % of tungsten and molybdenum combined;
- f) about 0.05 to about 4 wt % niobium and vanadium combined;
- g) about 0 to about 1 wt % titanium;
- h) about 0.01 to about 0.2 wt % aluminum;
- i) about 0.05 to about 3 wt % copper;
- j) less than about 1.5 wt % manganese;
- and
- g) at least 40% iron;
- wherein the alloy has a matrix that is essentially all austenite at room temperature and which is stable;
- wherein the alloy has a corrosion loss of less than 5 mg when about 12.7 mm of a cylindrical sample of the alloy having a diameter of 6.35 mm and a length of 31.75 mm and heated to about 300° F. (149° C.) is immersed in a 0.25 volume % solution of sulfuric acid at room temperature, withdrawn, heated again, and the cycle repeated for 1 hour, each cycle taking about 24 seconds;
- and
- wherein the alloy has a high temperature, pin-on-disc sliding wear resistance, measured using ASTM G99-90 at 500° F. (260° C.), with pin dimensions of 6.35 mm diameter and 25.4 mm length of Eatonite 6 valve facing alloy and a disk of the tested alloy having dimensions of 50.8 mm diameter and 12.5 mm thickness and after simple heat treatment of the disks at 1200° F. (649° C.) for two hours, at 0.13 m/s for 255 m, of less than 450 milligrams.
Dependencies are inferred from the claim text.