High-strength gray cast iron

Patent metadata

Field	Value
Publication number	US-10975458-B2
Application number	US-201815978331-A
Country	US
Kind code	B2
Filing date	May 14, 2018
Priority date	Dec 8, 2017
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

Disclosed herein is a gray cast iron having high strength and reduced casting defects. The high-strength gray cast iron may include: an amount of about 3.10 to 3.50 wt % of carbon (C), an amount of about 2.10 to 2.40 wt % of silicon (Si), an amount of about 0.50 to 0.80 wt % of manganese (Mn), an amount less than or equal to about 0.10 wt % (not including 0%) of phosphorus (P), an amount less than or equal to about 0.10 wt % (not including 0%) of sulfur (S), an amount of about 0.25 to 0.45 wt % of chromium (Cr), an amount of about 1.00 to 1.40 wt % of copper (Cu), an amount less than or equal to about 0.20 wt % (not including 0%) of nickel (Ni), and a balance of iron (Fe), all the wt % are based on the total weight of the gray cast iron. In particular, the gray cast iron may include a carbon equivalent (CEQ) of about 3.95 to 4.1% calculated by the Equation 1.

First claim

What is claimed is:

1. A gray cast iron, having a composition consisting of:
an amount of 3.10 to 3.50 wt % of carbon (C),
an amount of 2.10 to 2.40 wt % of silicon (Si),
an amount of 0.50 to 0.80 wt % of manganese (Mn),
an amount of more than 0 wt % and less than or equal to 0.10 wt % of phosphorous (P),
an amount of more than 0 wt % and less than or equal to 0.10 wt % of sulfur (S),
an amount of 0.25 to 0.45 wt % of chromium (Cr),
an amount of 1.00 to 1.40 wt % of copper (Cu),
an amount of more than 0 wt % and less than or equal to 0.20 wt % of nickel (Ni),
an amount of less than or equal to 0.10 wt % of molybdenum (Mo), and
a balance of iron (Fe),
all the wt % are based on the total weight of the gray cast iron,
wherein the gray cast iron has a carbon equivalent (CEQ) of 3.95 to 4.1% calculated by the following equation 1:
Carbon equivalent (CEQ)=C+1/3(Si+P),  [Equation 1]

where each of C, Si, and P in the Equation 1 represents an element content (wt %),
wherein the gray cast iron has a tensile strength of greater than or equal to 300 MPa,
wherein the gray cast iron has a hardness of 200 to 260 HB,
wherein the gray cast iron has a thermal conductivity of greater than or equal to 45 W/mK.

2. The gray cast iron according to claim 1 , wherein the gray cast iron has a solidification temperature of 1175 to 1185° C.

3. The gray cast iron according to claim 1 , wherein the gray cast iron has pearlite and ferrite and has a ferrite fraction of less than 1%.

4. The gray cast iron according to claim 1 , wherein the gray cast iron has a chromium carbide.

5. The gray cast iron according to claim 4 , wherein the gray cast iron has the chromium carbide 1 to 2 wt %.

6. A vehicle part comprising a gray cast iron of claim 1 .

7. The vehicle part of claim 6 , wherein the vehicle part is an engine.

8. A vehicle comprising a vehicle part of claim 6 .

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Park Hun Young

Classifications

• C22C37/10 Primary

  containing aluminium or silicon · CPC title

• C22C37/06 Primary

  containing chromium · CPC title

• C21D2211/009

  Pearlite · CPC title

• C21D2211/005

  Ferrite · CPC title

• C22C33/08

  Making cast-iron alloys · CPC title