Rolled magnesium alloy material, magnesium alloy structural member, and method for producing rolled magnesium alloy material

• US 9,598,749 B2
• Filed: 02/13/2012
• Issued: 03/21/2017
• Est. Priority Date: 02/14/2011
• Status: Active Grant

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Ito, Masahiko, Oishi, Yukihiro, Mori, Nobuyuki, Inoue, Ryuichi, Fujii, Masaaki, Kawabe, Nozomu
• Primary Examiner(s): Yang, Jie
• Application Number:
  US13/985,430
• Publication Number:
  US 20130315778A1
• Time in Patent Office: 1,863 Days
• Field of Search: 420/402, 420/497, 148/420
• US Class Current: 1/1
• CPC Class Codes: B21B 1/00 Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section B21B17/00 - B21B23/00 take precedence; with respect to composition of material to be rolled B21B3/00; extending closed shapes of metal bands by simultaneous rolling at two or more zones B21B5/00; metal-rolling stands as units B21B13/00; continuous casting into moulds having walls formed by moving rolls B22D11/06; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
• CPC Class Codes: B21B 3/00 Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metalsaltering special metallurgical properties of alloys, other than structure consolidation or mechanical properties resulting therefrom C21D, C22F
• CPC Class Codes: C22C 23/00 Alloys based on magnesium
• CPC Class Codes: C22C 23/02 with aluminium as the next major constituent
• CPC Class Codes: C22C 23/04 with zinc or cadmium as the next major constituent
• CPC Class Codes: C22C 23/06 with a rare earth metal as the next major constituent
• CPC Class Codes: C22F 1/06 of magnesium or alloys based thereon

Abstract

Provided are a rolled Mg alloy material whose mechanical properties are locally different in a width direction, a Mg alloy structural member produced by plastically working the rolled Mg alloy material, and a method for producing the rolled Mg alloy material. The method for producing a rolled Mg alloy material includes rolling a Mg alloy material with a reduction roll. The reduction roll has three or more regions in the width direction. The temperature is controlled in each of the regions so that a difference between a maximum temperature and a minimum temperature exceeds 10° C. in the width direction of a surface of the reduction roll. The rolled state in the width direction is varied by varying a difference in temperature over the width direction of the reduction roll. As a result, it is possible to produce a rolled Mg alloy material whose mechanical properties are locally different in the width direction.

Claims

1. A rolled magnesium alloy material produced by rolling a magnesium alloy material with a reduction roll,

wherein the magnesium alloy material contains aluminum in an amount of 8.3% by mass or more and 12% by mass or less,

wherein, in a width direction of the rolled magnesium alloy material,

a ratio O_E/O_C of a basal plane peak ratio of an edge portion to a basal plane peak ratio of a central portion satisfies O_E/O_C<

0.89,

where the basal plane peak ratio O_C of the central portion and the basal plane peak ratio O_E of the edge portion are represented by formulae below;

basal plane peak ratio O_C;

I_C(002)/{I_C(100)+I_C(002)+I_C(101)+I_C(102)+I_C(110)+I_C(103)}

basal plane peak ratio O_E;

I_E(002)/{I_E(100)+I_E(002)+I_E(101)+I_E(102)+I_E(110)+I_E(103)}

 

where I_C(002), I_C(100), I_C(101), I_C(102), I_C(110), and I_C(103) respectively represent X-ray diffraction peak intensities of a (002) plane, a (100) plane, a (101) plane, a (102) plane, a (110) plane, and a (103) plane in the central portion, and

I_E(002), I_E(100), I_E(101), I_E(102), I_E(110), and I_E(103) respectively represent X-ray diffraction peak intensities of the (002) plane, the (100) plane, the (101) plane, the (102) plane, the (110) plane, and the (103) plane in the edge portion,

wherein a thickness ratio t_E/t_C satisfies 0.97≦

t_E/t_C≦

1.03 where t_C denotes a thickness of a central portion in the width direction of the rolled Mg alloy material and t_E denotes a thickness of an edge portion in the width direction of the rolled Mg alloy material,

wherein an elongation ratio E_E/E_C of the edge portion to the central portion satisfies 3/2<

E_E/E_C, where E_C denotes an elongation of the central portion in a tensile test in a rolling direction and E_E denotes an elongation of the edge portion in a tensile test in a rolling direction.

2. The rolled magnesium alloy material according to claim 1,

wherein a tensile strength ratio Ts_E/Ts_C of the edge portion to the central portion satisfies Ts_E/Ts_C<

0.9,

where Ts_C denotes a tensile strength of the central portion in a tensile test in a rolling direction and Ts_E denotes a tensile strength of the edge portion in a tensile test in a rolling direction.

3. The rolled magnesium alloy material according to claim 1,

wherein a 0.2% proof stress ratio Ps_E/Ps_C of the edge portion to the central portion satisfies Ps_E/Ps_C<

0.9,

where Ps_C denotes a 0.2% proof stress of the central portion in a tensile test in a rolling direction and Ps_E denotes a 0.2% proof stress of the edge portion in a tensile test in a rolling direction.

4. The rolled magnesium alloy material according to claim 1,

wherein an average grain size ratio D_E/D_C of the edge portion to the central portion satisfies 3/2<

D_E/D_C,

where D_C denotes an average grain size of the central portion of a cross section orthogonal to a rolling direction and D_E denotes an average grain size of the edge portion of a cross section orthogonal to a rolling direction.

5. A magnesium alloy structural member produced by plastically working the rolled magnesium alloy material according to claim 1.