Forged beryllium-copper bulk material

Abstract

The present invention provides a forged beryllium-copper bulk material, wherein the hardness of the central portion is 0 to 10% higher than that of the front surface, the Vickers hardness of the central portion is 240 or more, the tensile strength is 800 N/mm 2 or more, and the bulk material having uniformity to such an extent that variation in measured values of the tensile strength in arbitrary directions is within 5%.

1 . A forged beryllium-copper bulk material, at least comprising Be and Cu,
 the hardness of the central portion being 0 to 10% higher than that of the front surface,   the Vickers hardness of the central portion being 240 or more,   the tensile strength being 800 N/mm 2  or more, and   the bulk material having uniformity to such an extent that variation in measured values of the tensile strength in arbitrary directions being within 5%.   
     
     
         2 . The forged beryllium-copper bulk material according to  claim 1 , wherein the tensile strength in three forging directions that are orthogonal to each other and the tensile strength measured, on a plane including two forging directions that are orthogonal to each other, in a direction making an angle of 45° with the two forging directions are 1100 N/mm 2  or more. 
     
     
         3 . The forged beryllium-copper bulk material according to  claim 1 , comprising a weight ratio of Cu 100−(a+b) Be a Co b  (0.4%≦a≦2.0%, 0.15%≦b≦2.8%, a+b≦3.5%) or a weight ratio of Cu 100−(c+d) Be c Ni d  (0.05%≦c≦0.6%, 1.0%≦d≦2.4%, c+d≦3.0%), wherein, Fe, S and P as impurities are limited to be lower than 0.01% in terms of the weight ratio. 
     
     
         4 . The forged beryllium-copper bulk material according to  claim 1 , wherein the Vickers hardness of the central portion is 240 to 450 and the tensile strength is 1100 to 1500 N/mm 2 . 
     
     
         5 . The forged beryllium-copper bulk material according to  claim 1 , comprising grains having an average grain size of 2 μm or lower, wherein the grains do not contain a shear band structure crossing a plurality of grains and are stable in the shape, and have a precipitated phase including the Be precipitated from the Cu. 
     
     
         6 . The forged beryllium-copper bulk material according to  claim 2 , comprising a weight ratio of Cu 100−(a+b) Be a Co b  (0.4%≦a≦2.0%, 0.15%≦b≦2.8%, a+b≦3.5%) or a weight ratio of Cu 100−(c+d) Be c Ni d  (0.05%≦c≦0.6%, 1.0%≦d≦2.4%, c+d≦3.0%), wherein Fe, S and P as impurities are limited to be lower than 0.01% in terms of the weight ratio. 
     
     
         7 . The forged beryllium-copper bulk material according to  claim 2 , wherein the Vickers hardness of the central portion is 240 to 450 and the tensile strength is 1100 to 1500 N/mm 2 . 
     
     
         8 . The forged beryllium-copper bulk material according to  claim 2 , comprising grains having an average grain size of 2 μm or lower, wherein the grains do not contain a shear band structure crossing a plurality of grains and are stable in the shape, and have a precipitated phase including the Be precipitated from the Cu.