Copper Cu: balance
Tin Sn: 6.0～7.0
Zinc Zn: 0.3
Lead Pb: ≤0.02
Aluminum Al: ≤0.002
Iron Fe: ≤0.05
Phosphorus P: ≤0.10-0.25
Nickel: ≤0.2
Total impurities: 0.1