CONTINUOUS CAST WIRE ROD OF Cu-Zn-Sn-BASED ALLOY

Abstract

This continuous cast wire rod contains Cu: 62.0 mass % or greater and 70.0 mass % or less, Sn: 0.3 mass % or greater and 0.9 mass % or less, Zr: 0.0050 mass % or greater and 0.1000 mass % or less, and P: 0.0050 mass % or greater and 0.1000 mass % or less, with a balance being Zn and impurities, and a mass ratio Zr/P of Zr to P is 0.3 or greater.

What is claimed is: 
     
         1 . A continuous cast wire rod of a Cu—Zn—Sn-based alloy containing Cu, Zn, and Sn, comprising:
 Cu: 62.0 mass % or greater and 70.0 mass % or less; 
 Sn: 0.3 mass % or greater and 0.9 mass % or less; 
 Zr: 0.0050 mass % or greater and 0.1000 mass % or less; and 
 P: 0.0050 mass % or greater and 0.1000 mass % or less, 
 with a balance being Zn and impurities, 
 wherein a mass ratio Zr/P of Zr to P is 0.3 or greater. 
 
     
     
         2 . The continuous cast wire rod of a Cu—Zn—Sn-based alloy according to  claim 1 ,
 wherein a tensile strength is 370 N/mm 2  or greater, and an elongation is 14% or greater. 
 
     
     
         3 . The continuous cast wire rod of a Cu—Zn—Sn-based alloy according to  claim 1 ,
 wherein a worked material after a working process has a tensile strength of 420 N/mm 2  or greater, an elongation of 22% or greater, and a 0.2% yield strength of 300 N/mm 2  or greater and 350 N/mm 2  or less, and 
 the working process includes: a first heat treatment of holding at 550° C. for 2 hours and subsequently conducing air cooling; a first cold working at a working ratio of 41%; a second heat treatment of holding at 550° C. for 2 hours and subsequently conducing air cooling; a second cold working at a working ratio of 41%; a third heat treatment of holding at 450° C. for 2 hours and subsequently conducing air cooling; and a third cold working at a working ratio of 11%. 
 
     
     
         4 . The continuous cast wire rod of a Cu—Zn—Sn-based alloy according to  claim 1 ,
 wherein a number density of Zr—P compounds containing Zr and P is in a range of 50 pieces/mm 2  or greater and 500 pieces/mm 2  or less. 
 
     
     
         5 . The continuous cast wire rod of a Cu—Zn—Sn-based alloy according to  claim 1 ,
 wherein Al is further contained in an amount of 0.20 mass % or greater and 0.80 mass % or less. 
 
     
     
         6 . The continuous cast wire rod of a Cu—Zn—Sn-based alloy according to  claim 1 ,
 wherein Sb is further contained in an amount of 0.02 mass % or greater and 0.06 mass % or less. 
 
     
     
         7 . The continuous cast wire rod of a Cu—Zn—Sn-based alloy according to  claim 1 , which is an up-drawn continuous cast wire rod.