Aluminium alloy forging and method of manufacture for same

Patent metadata

Field	Value
Publication number	US-9481920-B2
Application number	US-201113634731-A
Country	US
Kind code	B2
Filing date	Mar 8, 2011
Priority date	Mar 31, 2010
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

Disclosed is an aluminum alloy forging for use in automotive suspension parts and the like, and a method of manufacture for same. The aluminum alloy forging contains Si 0.4-1.5 wt %, Fe greater than 0.4 wt % and equal to or less than 1.0 wt %, Cu equal to or less than 0.40 wt %, Mg 0.8-1.3 wt % and Ti 0.01-0.1 wt %; Zn is restricted to equal to or less than 0.05 wt %; and the aluminum alloy forging contains at least one selected from among the following group comprising: Mn 0.01-1.0 wt % and Cr 0.1-0.4%; and Zr 0.05-0.2 wt %. Hydrogen content is restricted to 0.25 ml or less per 100 g of Al, and the remainder is composed of unavoidable impurities and Al. The average grain size is 50 μm or less, the crystallized area ratio is 3% or less, and the average crystallized grain size is 8 μm or less.

First claim

The invention claimed is:

1. An aluminum alloy forging, comprising:
Si: not less than 0.4% by mass but not more than 1.5% by mass,
Fe: not less than 0.45% mass but not more than 1.0% by mass,
Cu: not more than 0.40% by mass,
Mg: not less than 0.8% by mass but not more than 1.3% by mass,
Ti: not less than 0.01% by mass but not more than 0.1% by mass,
Zn: not more than 0.05%,
at least one member selected from the group consisting of Mn: no less than 0.01% by mass but not more than 1.0% by mass, Cr: not less than 0.1% by mass but not more than 0.4% by mass, and Zr: not less than 0.05% by mass but not more than 0.2% by mass,
hydrogen: not more than 0.25 ml/100 g Al, and
Al,
wherein the aluminum alloy forging has an average grain size of 50 μm or lower, a crystallized area ratio of 3% or lower, and an average crystallized grain size of 8 μm or lower.

2. The aluminum alloy forging of claim 1 , which comprises Fe: not less than 0.45% by mass but not more than 0.7% by mass.

3. The aluminum alloy forging of claim 1 , further comprising at least one of C, Ni, Na, Ca, V, and Hf in a total amount of not more than 0.1% by mass.

4. The aluminum alloy forging of claim 1 , further comprising B: not more than 300 ppm.

5. The aluminum alloy forging of claim 1 , which has the average grain size of 45 μm or lower.

6. The aluminum alloy forging of claim 1 , which has the average grain size of 40 μm or lower.

7. The aluminum alloy forging of claim 1 , which has the crystallized area ratio of 2.5% or lower.

8. The aluminum alloy forging of claim 1 , which has the crystallized area ratio of 2.0% or lower.

9. The aluminum alloy forging of claim 1 , which has the average crystallized grain size of 6 μm or lower.

10. A method for manufacturing the aluminum alloy forging of claim 1 , the method comprising:
casting, at a heating temperature of 710 to 810° C. and at a casting rate 230 to 330 m m/min an ingot of an aluminum alloy comprising:
Si: not less than 0.4% by mass but not more than 1.5% by mass,
Fe: not less than 0.45% by mass but not more than 1.0% by mass,
Cu: not more than 0.40% by mass,
Mg: not less than 0.8% by mass but not more than 1.3% by mass,
Ti: not less than 0.01% by mass but not more than 0.1% by mass,
Zn: not more than 0.05%,
at least one member selected from the group consisting of Mn: not less than 0.01% by mass but not more than 1.0% by mass, Cr: not less than 0.1% by mass but not more than 0.4% by mass, and Zr: not less than 0.05% by mass not more than 0.2% by mass,
hydrogen: not more than 0.25 ml/100 g Al, and
Al;

subjecting the ingot to a homogenizing heat treatment at 420 to 560° C. for 2.5 to 8 hours;
heating the ingot which has been subjected to the homogenizing heat treatment at 470 to 545° C. for 0.5 hours or longer to obtain a heated ingot;
forging the heated ingot at a temperature of 330° C. or higher and at a draft of 50 to 95% after completion of the forging to obtain a forging in a predetermined shape;
subjecting the forging in a predetermined shape to a solution treatment at 480 to 580° C. for longer than 0 hours but not longer than 24 hours;
hardening the forging which has been subjected to the solution treatment at 75° C. or lower to obtain a hardened forging; and
subjecting the hardened forging at 160 to 250° C. for 0.5 to 20 hours to artificial aging.

Assignees

• Hori Masayuki
• Inagaki Yoshiya
• Kobe Steel Ltd

Inventors

• Hori Masayuki
• Inagaki Yoshiya

Classifications

• C22C21/06

  with magnesium as the next major constituent · CPC title

• C22C21/02 Primary

  with silicon as the next major constituent · CPC title

• B22D21/007

  with low melting point, e.g. Al 659 degrees C, Mg 650 degrees C · CPC title

• C22F1/05

  of alloys of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions · CPC title

• C22F1/00

  Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working (apparatus for mechanical working of metal B21, B23, B24) · CPC title