Back to results
US 5,580,401 AGranted
Gray cast iron system for scroll machines
AssigneeCopeland Corporation
InventorWarren G. Williamson
Life of this patent
Estimating the term…
Abstract
A system for making a gray cast iron scrolls using a high performance inoculant.
Claims19
A gray cast iron scroll for use in scroll machine comprising:
- (a) a base portion;
- and
- (b) a vane portion adjoining said base portion;
- said base portion and said vane portion being composed of a material having a final composition comprising:
- (i) carbon in an amount of about 3.0 to about 3.9% by weight;
- (ii) silicon in an amount of about 1.5 to about 3.2% by weight;
- (iii) manganese in an amount of about 0.2 to about 1.25% by weight;
- (iv) a high performance inoculant present in an amount of about 3 to about 100 ppm;
- and
- (v) the balance iron;
- said base portion and said vane portion having a microstructure of type A graphite and a pearlite matrix, throughout substantially their entire structure;
- and
- said base portion and said vane portion being capable of exhibiting said microstructure substantially throughout said scroll.
10 more elements
A method for manufacturing a gray cast iron scroll for use in a scroll machine, said method comprising the steps of:
- (a) providing a mold having defined therein a cavity for casting a scroll with a base portion integrally adjoined with and a vane portion;
- (b) preparing a melt of a ferrous base material;
- (c) inoculating said melt with a high-performance inoculant selected from strontium, a lanthanide series rare earth element, or mixtures thereof;
- (d) alloying said melt with a pearlite stabilizer;
- (e) maintaining said melt at a temperature of at least about 2690.degree. F. (1477.degree.C.);
- (f) lowering said melt temperature to a temperature of about 2500.degree. F. to about 2640.degree. F.;
- and
- (g) pouring said melt into said mold cavity to cast said scroll, wherein said scroll exhibits a microstructure of Type A graphite and a pearlite matrix throughout substantially the entire structure, and said base member and said vane member in said scroll is capable of exhibiting said microstructure throughout a section having a thickness of as low as about 4 millimeters, as-cast.
5 more elements
A method for manufacturing a gray cast iron scroll for use in a scroll machine, said method comprising the steps of:
- (a) casting a vane portion, and a base portion of said scroll for adjoining said vane portion;
- (b) preventing formation of type C, type D, and type E graphite in said scroll;
- (c) forming pearlite throughout both said vane portion and said base portion, said pearlite having a substantially uniform structure throughout said vane portion and said base portion;
- (d) forming a dispersion of Type A graphite in said pearlite matrix;
- and
- (e) finishing said scroll, whereby removal of no greater than about 1.5 millimeters of finish stock is necessary.
3 more elements
A gray cast iron scroll for use in a scroll machine, comprising:
- (a) a base portion;
- and
- (b) a vane portion adjoining said base portion;
- said base portion and said vane portion being composed of a material having a final composition comprising:
- (i) carbon in an amount of about 3.0 to about 3.9% by weight;
- (ii) silicon in an amount of about 1.5 to about 3.2% by weight;
- (iii) manganese in an amount of about 0.2 to about 1.25% by weight;
- (iv) a high performance inoculant including strontium present in an amount of about 3 to about 100 ppm;
- and
- (v) the balance iron;
- said base portion and said vane portion having a microstructure of type A graphite and a pearlite matrix, throughout substantially their entire structure;
- and
- said base portion and said vane portion being capable of exhibiting said microstructure substantially throughout said scroll.
10 more elements
Dependencies are inferred from the claim text.