Dowa Metaltech Co., Ltd.

Toshiya Shutoh

Hisashi Suda

Fumiaki Sasaki

To provide, as a sheet material of a Cu—Ni—Al based copper alloy having a compositional range exhibiting a whitish metallic appearance that is excellent in 'strength-bending workability balance' and is excellent in discoloration resistance, a copper alloy sheet material having a composition containing, in terms of % by mass, Ni: more than 12.0% and 30.0% or less, Al: 1.80-6.50%, Mg: 0-0.30%, Cr: 0-0.20%, Co: 0-0.30%, P: 0-0.10%, B: 0-0.05%, Mn: 0-0.20%, Sn: 0-0.40%, Ti: 0-0.50%, Zr: 0-0.20%, Si: 0-0.50%, Fe: 0-0.30%, and Zn: 0-1.00%, with the balance of Cu and unavoidable impurities, and satisfying Ni/Al≤15.0, and having a metallic structure having, on an observation plane in parallel to a sheet surface (rolled surface), a number density of fine secondary phase particles having a particle diameter of 20 to 100 nm of 1.0×10per mmor more.

Cu—Ni—Al based copper alloy sheet material, method for producing same, and conductive spring member

A copper alloy sheet material that is excellent in surface smoothness of an etched surface has a composition containing, (mass %), from 1.0 to 4.5% of Ni, from 0.1 to 1.2% of Si, from 0 to 0.3% of Mg, from 0 to 0.2% of Cr, from 0 to 2.0% of Co, from 0 to 0.1% of P, from 0 to 0.05% of B, from 0 to 0.2% of Mn, from 0 to 0.5% of Sn, from 0 to 0.5% of Ti, from 0 to 0.2% of Zr, from 0 to 0.2% of Al, from 0 to 0.3% of Fe, from 0 to 1.0% of Zn, the balance Cu and unavoidable impurities. A number density of coarse secondary phase particles has a major diameter of 1.0 &#x3bc;m or more of 4.0&#xd7;10per square millimeter or less. KAM value measured with a step size of 0.5 &#x3bc;m is more than 3.00.

Growing community of inventors

Tokyo, Japan

Toshiya Shutoh