Aluminium alloy forging and method of manufacture for same

• US 9,481,920 B2
• Filed: 03/08/2011
• Issued: 11/01/2016
• Est. Priority Date: 03/31/2010
• Status: Active Grant

• Current Assignee: Klaus Schmidt
• Original Assignee: Kobe Steel Limited
• Inventors: Hori, Masayuki, Inagaki, Yoshiya
• Primary Examiner(s): King, Roy
• Assistant Examiner(s): Morillo, Janelle
• Application Number:
  US13/634,731
• Publication Number:
  US 20130032255A1
• Time in Patent Office: 2,065 Days
• US Class Current: 1/1
• CPC Class Codes: B21J 1/06 Heating or cooling methods or arrangements specially adapted for performing forging or pressing operations B21J5/063 takes precedence
• CPC Class Codes: B21K 1/74 forked members or members with two or more limbs, e.g. U-bolts, anchors
• CPC Class Codes: B22D 21/007 with low melting point, e.g. Al 659 degrees C, Mg 650 degrees C
• CPC Class Codes: C22C 21/02 with silicon as the next major constituent
• CPC Class Codes: C22C 21/06 with magnesium as the next major constituent
• CPC Class Codes: C22C 21/08 with silicon
• CPC Class Codes: C22F 1/00 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 Class Codes: C22F 1/05 of alloys of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions

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.

Claims

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 μ

m or lower, a crystallized area ratio of 3% or lower, and an average crystallized grain size of 8 μ

m 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 μ

m or lower.

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

m 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 μ

m 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.