Copper alloy material excellent in strength, bending workability and stress relaxation resistance, and method for producing the same

Abstract

A copper alloy material according to the present invention is characterized in that the same comprises: Ni between 2.8 mass % and 5.0 mass %; Si between 0.4 mass % and 1.7 mass %; S of which content is limited to less than 0.005 mass %; and the balance of the copper alloy material is composed of copper and unavoidable impurity, wherein a proof stress is stronger than or equal to 800 MPa, and the same is superior in bending workability and in stress relaxation resistance.

1 .- 6 . (canceled) 
     
     
         7 . A copper alloy material, comprising:
 Ni between 2.8 mass % and 5.0 mass %;   Si between 0.4 mass % and 1.7 mass %;   S of which content is limited to less than 0.005 mass %; and the balance of the copper alloy material is composed of copper and unavoidable impurity,   wherein a proof stress is stronger than or equal to 800 MPa, and   the copper alloy material is superior in bending workability and in stress relaxation resistance.   
     
     
         8 . The copper alloy material according to  claim 7 ,
 further comprising at least one nature of Mg between 0.01 mass % and 0.20 mass %, Sn between 0.05 mass % and 1.5 mass % and Zn between 0.2 mass % and 1.5 mass %.   
     
     
         9 . The copper alloy material according to  claim 7 ,
 further comprising at least any one nature or more than or equal to any two natures in the following (I) to (IV) between 0.005 mass % and 2.0 mass % in total:
 (I) at least any one nature or more than or equal to any two natures between 0.005 mass % and 0.3 mass % that is selected from a group of Sc, Y, Ti, Zr, Hf, V, Mo and Ag; 
 (II) Mn between 0.01 mass % and 0.5 mass %; 
 (III) Co between 0.05 mass % and 2.0 mass %; and 
 (IV) Cr between 0.005 mass % and 1.0 mass %. 
   
     
     
         10 . The copper alloy material according to  claim 8 ,
 further comprising at least any one nature or more than or equal to any two natures in the following (I) to (IV) between 0.005 mass % and 2.0 mass % in total:
 (I) at least any one nature or more than or equal to any two natures between 0.005 mass % and 0.3 mass % that is selected from a group of Sc, Y, Ti, Zr, Hf, V, Mo and Ag; 
 (II) Mn between 0.01 mass % and 0.5 mass %; 
 (III) Co between 0.05 mass % and 2.0 mass %; and 
 (IV) Cr between 0.005 mass % and 1.0 mass %. 
   
     
     
         11 . The copper alloy material according to  claim 7 ,
 wherein a grain of matrix size is larger than 0.001 mm but smaller than or equal to 0.025 mm, and   a ratio (a/b) between a major axis (a) of a grain of matrix on a cross section which is parallel to a direction for a final plastic working and a major axis (b) of said grain of matrix on said cross section which is at right angles to said direction for said final plastic working is higher than or equal to 0.8 but lower than or equal to 1.5.   
     
     
         12 . The copper alloy material according to  claim 8 ,
 wherein a grain of matrix size is larger than 0.001 mm but smaller than or equal to 0.025 mm, and   a ratio (a/b) between a major axis (a) of a grain of matrix on a cross section which is parallel to a direction for a final plastic working and a major axis (b) of said grain of matrix on said cross section which is at right angles to said direction for said final plastic working is higher than or equal to 0.8 but lower than or equal to 1.5.   
     
     
         13 . The copper alloy material according to  claim 9 ,
 wherein a grain of matrix size is larger than 0.001 mm but smaller than or equal to 0.025 mm, and   a ratio (a/b) between a major axis (a) of a grain of matrix on a cross section which is parallel to a direction for a final plastic working and a major axis (b) of said grain of matrix on said cross section which is at right angles to said direction for said final plastic working is higher than or equal to 0.8 but lower than or equal to 1.5.   
     
     
         14 . The copper alloy material according to  claim 10 ,
 wherein a grain of matrix size is larger than 0.001 mm but smaller than or equal to 0.025 mm, and   a ratio (a/b) between a major axis (a) of a grain of matrix on a cross section which is parallel to a direction for a final plastic working and a major axis (b) of said grain of matrix on said cross section which is at right angles to said direction for said final plastic working is higher than or equal to 0.8 but lower than or equal to 1.5.   
     
     
         15 . The copper alloy material according to  claim 7 ,
 wherein a maximum value of a difference between a proof stress in a rolling direction and a proof stress in a direction of which has an angle of 90 degrees against said rolling direction is lower than or equal to 100 MPa.   
     
     
         16 . The copper alloy material according to  claim 8 ,
 wherein a maximum value of a difference between a proof stress in a rolling direction and a proof stress in a direction of which has an angle of 90 degrees against said rolling direction is lower than or equal to 100 MPa.   
     
     
         17 . The copper alloy material according to  claim 9 ,
 wherein a maximum value of a difference between a proof stress in a rolling direction and a proof stress in a direction of which has an angle of 90 degrees against said rolling direction is lower than or equal to 100 MPa.   
     
     
         18 . The copper alloy material according to  claim 10 ,
 wherein a maximum value of a difference between a proof stress in a rolling direction and a proof stress in a direction of which has an angle of 90 degrees against said rolling direction is lower than or equal to 100 MPa.   
     
     
         19 . The copper alloy material according to  claim 11 ,
 wherein a maximum value of a difference between a proof stress in a rolling direction and a proof stress in a direction of which has an angle of 90 degrees against said rolling direction is lower than or equal to 100 MPa.   
     
     
         20 . The copper alloy material according to  claim 12 ,
 wherein a maximum value of a difference between a proof stress in a rolling direction and a proof stress in a direction of which has an angle of 90 degrees against said rolling direction is lower than or equal to 100 MPa.   
     
     
         21 . The copper alloy material according to  claim 13 ,
 wherein a maximum value of a difference between a proof stress in a rolling direction and a proof stress in a direction of which has an angle of 90 degrees against said rolling direction is lower than or equal to 100 MPa.   
     
     
         22 . The copper alloy material according to  claim 14 ,
 wherein a maximum value of a difference between a proof stress in a rolling direction and a proof stress in a direction of which has an angle of 90 degrees against said rolling direction is lower than or equal to 100 MPa.   
     
     
         23 . A method for producing the copper alloy material according to any of  claims 7  to  22 , comprising the steps of:
 performing a processing in order to obtain a solution heat treated recrystallized structure in a plate of a copper alloy; and   performing thereafter a series of processing of a cold rolling as a first term and then an aging treatment, and then another cold rolling as a second term and then a low temperature annealing,   wherein following formulas (1) to (3) are satisfied, in a case where a variation of a proof stress after said low temperature annealing is defined to be Δtotal (MPa) that is based on a proof stress immediately before said cold rolling as said first term, where a variation of a proof stress before and after said cold rolling as said first term is defined to be ΔC1 (MPa), and where a variation of a proof stress before and after said cold rolling as said second term is defined to be ΔC2 (MPa):
   0.1 ≦ΔC 1/Δtotal≦0.35  (1); 
   0 ≦ΔC 2/Δtotal≦0.35  (2); 
   0.1≦(Δ C 1 +ΔC 2)/Δtotal≦0.45  (3).