Bronze-based alloy of low lead content

Abstract

The object of the present invention is to provide a bronze-based alloy of low lead content, first improved in tensile strength at high temperatures, secondly contributing to the promotion of the environmental conservation including recycling, while avoiding the adverse effect of lead on human bodies by means of reduction of a lead content, and excellent from the standpoints of mass-productivity and manufacturing cost. The alloy includes 2.0 to 6.0 mass % of Sn, 3.0 to 10.0 mass % of Zn, 0.1 to 3.0 mass % of Bi, 0.1 mass %<P≦0.6 mass % and the remainder of Cu and unavoidable impurities to improve the tensile strength thereof at high temperatures.

1 . A bronze-based alloy of low lead content, comprising 2.0 to 6.0 mass % of Sn, 3.0 to 10.0 mass % of Zn, 0.1 to 3.0 mass % of Bi, 0.1 mass %<P≦0.6 mass % and the remainder of Cu and unavoidable impurities to improve tensile strength thereof at high temperatures. 
   
   
       2 . A bronze-based alloy of low lead content, comprising 2.0 to 6.0 mass % of Sn, 3.0 to 10.0 mass % of Zn, 0.1 to 3.0 mass % of Bi, 0.1 mass %<P≦0.6 mass %, 0.0 mass %<Ni≦3.0 mass % and the remainder of Cu and unavoidable impurities to improve tensile strength thereof at high temperatures and secure soundness of a casting. 
   
   
       3 . A bronze-based alloy of low lead content, comprising 2.0 to 6.0 mass % of Sn, 3.0 to 10.0 mass % of Zn, 0.1 to 3.0 mass % of Bi, 0.1 mass %<P≦0.6 mass %, 0.0 mass %<Se≦1.3 mass % and the remainder of Cu and unavoidable impurities to improve tensile strength thereof at high temperatures and secure soundness of a casting. 
   
   
       4 . A bronze-based alloy of low lead content, comprising 2.0 to 6.0 mass % of Sn, 3.0 to 10.0 mass % of Zn, 0.1 to 3.0 mass % of Bi, 0.1 mass %<P≦0.6 mass %, 0.0 mass %<Ni<3.0 mass %, 0.0 mass %<Se≦1.3 mass % and the remainder of Cu and unavoidable impurities to improve tensile strength thereof at high temperatures and secure soundness of a casting. 
   
   
       5 . A bronze-based alloy of low lead content according to  claim 1 , further comprising 0.005 to 2.0 mass % of Pb to secure a tensile strength of at least 152 MPa at a temperature of 180° C. 
   
   
       6 . A bronze-based alloy of low lead content according to  claim 1 , that secures a tensile strength of at least 152 MPa at a temperature of 180° C. in an alloy region having a secondary dendrite spacing of 14 μm or more. 
   
   
       7 . A valve, water faucet clasp or water meter comprising the bronze-based alloy of low lead content according to  claim 1 . 
   
   
       8 . A bronze-based alloy of low lead content according to  claim 2 , further comprising 0.005 to 2.0 mass % of Pb to secure a tensile strength of at least 152 MPa at a temperature of 180° C. 
   
   
       9 . A bronze-based alloy of low lead content according to  claim 3 , further comprising 0.005 to 2.0 mass % of Pb to secure a tensile strength of at least 152 MPa at a temperature of 180° C. 
   
   
       10 . A bronze-based alloy of low lead content according to  claim 4 , further comprising 0.005 to 2.0 mass % of Pb to secure a tensile strength of at least 152 MPa at a temperature of 180° C. 
   
   
       11 . A bronze-based alloy of low lead content according to  claim 2 , that secures a tensile strength of at least 152 MPa at a temperature of 180° C. in an alloy region having a secondary dendrite spacing of 14 μm or more. 
   
   
       12 . A bronze-based alloy of low lead content according to  claim 3 , that secures a tensile strength of at least 152 MPa at a temperature of 180° C. in an alloy region having a secondary dendrite spacing of 14 μm or more. 
   
   
       13 . A bronze-based alloy of low lead content according to  claim 4 , that secures a tensile strength of at least 152 MPa at a temperature of 180° C. in an alloy region having a secondary dendrite spacing of 14 μm or more. 
   
   
       14 . A valve, water faucet clasp or water meter comprising the bronze-based alloy of low lead content according to  claim 2 . 
   
   
       15 . A valve, water faucet clasp or water meter comprising the bronze-based alloy of low lead content according to  claim 3 . 
   
   
       16 . A valve, water faucet clasp or water meter comprising the bronze-based alloy of low lead content according to  claim 4 . 
   
   
       17 . A valve, water faucet clasp or water meter comprising the bronze-based alloy of low lead content according to  claim 5 . 
   
   
       18 . A valve, water faucet clasp or water meter comprising the bronze-based alloy of low lead content according to  claim 6 .