Method for fabricating vane using a nodular graphite cast iron

Patent metadata

Field	Value
Publication number	US-9644245-B2
Application number	US-201514613284-A
Country	US
Kind code	B2
Filing date	Feb 3, 2015
Priority date	Nov 14, 2011
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A nodular graphite cast iron, a method for fabricating a vane for a rotary compressor using nodular graphite cast iron, and a vane for a rotary compressor using the same are provided. The nodular graphite cast iron includes 3.4 wt % to 3.9 wt % of carbon (C), 2.0 wt % to 3.0 wt % of silicon (Si), 0.3 wt % to 1.0 wt % of manganese (Mn), 0.1 wt % to 1.0 wt % of chromium (Cr), 0.04 wt % to 0.15 wt % of titanium (Ti), less than 0.08 w % of phosphorus (P), less than 0.025 wt % of sulphur (S), 0.03 wt % to 0.05 wt % of magnesium (Mg), 0.02 wt % to 0.04 wt % of rare earth resource, iron (Fe) and impurities as the remnants, and includes a bainite matrix structure, nodular graphite, and 15 vol % to 35 vol % of carbide.

First claim

What is claimed is:

1. A method for fabricating a vane for a compressor, the method comprising:
melting a molten metal including 3.4 wt % to 3.9 wt % of carbon (C), 2.0 wt % to 3.0 wt % of silicon (Si), 0.3 wt % to 1.0 wt % of manganese (Mn), 0.1 wt % to 1.0 wt % of chromium (Cr), 0.04 wt % to 0.15 wt % of titanium (Ti), less than 0.08 w % of phosphorus (P), less than 0.025 wt % of sulphur (S), 0.03 wt % to 0.05 wt % of magnesium (Mg), 0.02 wt % to 0.04 wt % of rare earth resource, iron (Fe) and impurities as the remnants;
injecting the molten metal into a mold in a casting operation;
cooling the mold to obtain a semi-product including nodular graphite and 15 vol % to 35 vol % of carbide;
grinding the cooled semi-product to have a predetermined shape in a grinding operation; and
thermally treating the grinded product in a heat treatment to transform an austenite matrix structure into a bainite matrix structure.

2. The method of claim 1 , further comprising: taking out the molten metal; and
applying a spheroidizing agent to the molten metal.

3. The method of claim 1 , wherein the heat treatment comprises:
heating the grinded semi-product to 880° C. to 950° C.;
maintaining the semi-product at the temperature for 30 to 90 minutes;
maintaining the semi-product in a liquid having a temperature ranging from 200° C. to 260° C. for one to three hours; and
cooling the semi-product to reach room temperature.

4. The method of claim 3 , wherein the liquid is a nitrate solution in which KNO 3 and NaNO 3 are mixed in the weight ratio of 1:1.

5. The method of claim 1 , further comprising a finely grinding the heat treatment-completed semi-product in a fine grinding operation.

6. The method of claim 1 , further comprising forming a sulphurized layer having a thickness ranging from 0.005 mm˜0.0015 mm on a surface of the heat treatment-completed semi-product.

7. The method of claim 2 , wherein the vane comprises 0.2 wt % to 0.8 wt % of molybdenum (Mo).

8. The method of claim 2 , wherein the vane further comprises 0.05 wt % to 0.5 wt % of tungsten (W).

9. The method of claim 2 , wherein the vane further comprises 0.01 wt % to 0.3 wt % of boron (B).

Assignees

• Lg Electronics Inc

Inventors

• Park Jaebong

Classifications

• C22C37/06

  containing chromium · CPC title

• F01C21/0809

  Construction of vanes or vane holders · CPC title

• B22D27/20

  Measures not previously mentioned for influencing the grain structure or texture; Selection of compositions therefor · CPC title

• F04C18/356

  with vanes reciprocating with respect to the outer member · CPC title

• F04C2230/21

  by casting · CPC title