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.

Abstract: Free-cutting copper alloy comprises Cu: more than 59.7% but less than 64.7%, Si: more than 0.60% but less than 1.30%, Pb: more than 0.001% but less than 0.20%, Bi: more than 0.001% but less than 0.10 mass %, and P: more than 0.001% but less than 0.15%, with remainder being Zn and unavoidable impurities, wherein total amount of Fe, Mn, Co, and Cr is less than 0.45%, the total amount of Sn and Al is less than 0.45%, 56.7?Cu?4.7×Si+0.5×Pb+0.5×Bi?0.5×P?59.7 and 0.003?Pb+Bi<0.25 are satisfied, 0.02?Bi/(Pb+Bi)?0.98 is satisfied if 0.003?Pb+Bi<0.08, 0.01?Bi/(Pb+Bi)?0.40 or 0.85?Bi/(Pb+Bi)?0.98 is satisfied if 0.08?Pb+Bi<0.13.

Abstract: This free-cutting copper alloy contains Cu: more than 57.5% but less than 64.5%, Si: more than 0.20% but less than 1.20%, Pb: more than 0.001% but less than 0.20%, Bi: more than 0.10% but less than 1.00%, and P: more than 0.001% but less than 0.20%, with the balance being Zn and unavoidable impurities, wherein the total amount of Fe, Mn, Co and Cr is less than 0.45%, the total amount of Sn and Al is less than 0.45%, relationships of 56.3?f1=[Cu]?4.8×[Si]+0.5×[Pb]+0.5×[Bi]?0.5×[P]?59.5 and 0.12?f2=[Pb]+[Bi]<1.0 are satisfied.

Abstract: This free-cutting copper alloy includes Cu: more than 58.0% and less than 65.0%, Si: more than 0.30% and less than 1.30%, Pb: more than 0.001% and 0.20% or less, Bi: more than 0.020% and 0.10% or less, and P: more than 0.001% and less than 0.20%, with the remainder being Zn and unavoidable impurities, a total amount of Fe, Mn, Co and Cr is less than 0.45%, a total amount of Sn and Al is less than 0.45%, relationships of 56.5?[Cu]?4.7×[Si]+0.5×[Pb]+0.5×[Bi]?0.5×[P]?59.5, and 0.025?[Pb]+[Bi]<0.25 are satisfied, in constituent phases of a metallographic structure, relationships of 20?(?)<85, 15<(?)?80, 0?(?)<5, 8.0?([Bi]+[Pb]?0.002)1/2×10+([P]?0.001)1/2×5+((?)?7)1/2×([Si]?0.1)1/2×1.2+(?)1/2×0.5?17.0, and 0.9?([Bi]+[Pb]?0.002)1/2×((?)?7)1/2×([Si]?0.1)1/2?4.0 are satisfied, and a particle containing Bi is present in ? phase.

Abstract: A wire rod of a Cu—Zn—Si based alloy obtained by up-drawing continuous casting is provided; the amount of Cu is within a range of 75.0 mass% or more and 76.9 mass% or less, the amount of Si is within a range of 2.6 mass% or more and 3.1 mass% or less, the amount of Zr is within a range of 0.003 mass% or more and 0.20 mass% or less, the amount of P is within a range of 0.02 mass% or more and 0.15 mass% or less, the balance is composed of Zn and inevitable impurities, and the number density of a Zr—P compound containing Zr and P is within a range of 1500 pieces/mm2 or more and 7000 pieces/mm2 or less.

Abstract: The present invention provides a surface treatment method that improves antimicrobial activity of copper or a copper alloy and enhances immediate effects of antimicrobial actions on the surface of the copper or the copper alloy. A surface treatment method for copper or a copper alloy according to the present invention comprises preparing a reducing agent solution containing a biological reducing substance, and treating the surface of the copper or the copper alloy with the reducing agent solution. The present invention also provides a surface treatment liquid for sterilizing copper or a copper alloy, in which the surface treatment liquid contains a biological reducing substance. The present invention also provides a sterilization method that comprises bringing copper or a copper alloy treated by the surface treatment method into contact with a surface of an object to sterilize the surface of the object.

Abstract: The present invention provides a surface treatment method that improves antimicrobial activity of copper or a copper alloy and enhances immediate effects of antimicrobial actions on the surface of the copper or the copper alloy. A surface treatment method for copper or a copper alloy according to the present invention comprises preparing a reducing agent solution containing a biological reducing substance, and treating the surface of the copper or the copper alloy with the reducing agent solution. The present invention also provides a surface treatment liquid for sterilizing copper or a copper alloy, in which the surface treatment liquid contains a biological reducing substance. The present invention also provides a sterilization method that comprises bringing copper or a copper alloy treated by the surface treatment method into contact with a surface of an object to sterilize the surface of the object.

Abstract: This free-cutting copper alloy contains Cu: 58.5 to 63.5%, Si: more than 0.4% and 1.0% or less, Pb: 0.003 to 0.25%, and P: 0.005 to 0.19%, with the remainder being Zn and inevitable impurities, a total amount of Fe, Mn, Co and Cr is less than 0.40%, a total amount of Sn and Al is less than 0.40%, a relationship of 56.3?f1=[Cu]?4.7×[Si]+0.5×[Pb]?0.5×[P]?59.3 is satisfied, constituent phases of a metal structure have relationships of 20?(?)?75, 25?(?)?80, 0?(?)<2, 20?(?)1/2×3+(?)×(?0.5×([Si])2+1.5×[Si])?78, and 33?(?)1/2×3+(?)×(?0.5×([Si])2+1.5×[Si])+([Pb])1/2×33+([P])1/2×14, and a compound including P is present in ? phase.

Abstract: This free-cutting copper alloy includes Cu: more than 61.0% and less than 65.0%, Si: more than 1.0% and less than 1.5%, Pb: 0.003% to less than 0.20%, and P: more than 0.003% and less than 0.19%, with the remainder being Zn and unavoidable impurities, a total content of Fe, Mn, Co, and Cr is less than 0.40%, a total content of Sn and Al is less than 0.40%, a relationship of 56.5?f1=[Cu]?4.5×[Si]+0.5×[Pb]?[P]?59.5 is satisfied, constituent phases of a metallographic structure have relationships of 20?(?)?80, 15?(?)?80, 0?(?)<8, 18×(?)/(?)<9, 20?(?)1/2×3+(?)×([Si])1/2?88, and 33?(?)1/2×3+(?)×([Si])1/2+([Pb])1/2×35+([P])1/2×15, and a compound including P is present in ? phase.

Abstract: This free-cutting copper alloy comprises 75.4-78.7% Cu, 3.05-3.65% Si, 0.10-0.28% Sn, 0.05-0.14% P, and at least 0.005% to less than 0.020% Pb, with the remainder comprising Zn and inevitable impurities. The composition satisfies the following relations: 76.5?f1=Cu+0.8×Si?8.5×Sn+P?80.3; 60.7?f2=Cu?4.6×Si?0.7×Sn?P?62.1; and 0.25?f7=P/Sn?1.0. The area percentage (%) of respective constituent phases satisfies the following relations: 28???67; 0???1.0; 0???0.2; 0???1.5; 97.4?f3=?+?; 99.4?f4=?+?+?+?; 0?f5=?+??2.0; and 30?f6=?+6×?1/2+0.5×??70. The long side of the ? phase is at most 40 ?m, the long side of the ? phase is at most 25 ?m, and ? phase is present in ? phase.

Abstract: This copper alloy casting includes, in terms of mass %: Cu: higher than 58.5% and lower than 65.0%; Si: higher than 0.40% and lower than 1.40%; Pb: higher than 0.002% and lower than 0.25%; P: higher than 0.003% and lower than 0.19%; and Bi: 0.001% to 0.100% as an optional element, with the balance being Zn and inevitable impurities, the total content of Fe, Mn, Co, and Cr is lower than 0.45% and the total content of Sn and Al is lower than 0.45%, a relationship of 56.0?f1=[Cu]?5×[Si]+0.5×[Pb]+0.5×[Bi]?0.5×[P]?59.5 is satisfied, when Bi is included, a relationship of 0.003<f0=[Pb]+[Bi]<0.25 is further satisfied.

Abstract: This free-cutting copper alloy casting contains: 76.0-79.0% Cu, 3.1-3.6% Si, 0.36-0.85% Sn, 0.06-0.14% P, 0.022-0.10% Pb, with the remainder being made up of Zn and unavoidable impurities. This composition satisfies the following relations: 75.5?f1=Cu+0.8×Si?7.5×Sn+P+0.5×Pb?78.7, 60.8?f2=Cu?4.5×Si—0.8×Sn?P+0.5×Pb?62.2, 0.09?f3=P/Sn?0.35. The area ratios (%) of the constituent phases satisfy the following relations, 30???63, 0???2.0, 0???0.3, 0???2.0, 96.5?f4=?+?, 99.3?f5=?+?+?+?, 0?f6=?+??3.0, and 37?f7=1.05×?+6×?1/2+0.5×??72. The ? phase is present within the ? phase, the long side of the ? phase does not exceed 50 ?m, and the long side of the ? phase does not exceed 25 ?m.

Abstract: This free-cutting copper alloy comprises 76.0-78.7% Cu, 3.1-3.6% Si, 0.40-0.85% Sn, 0.05-0.14% P, and at least 0.005% to less than 0.020% Pb, with the remainder comprising Zn and inevitable impurities. The composition satisfies the following relations: 75.0?f1=Cu+0.8×Si?7.5×Sn+P+0.5×Pb?78.2; 60.0?f2=Cu?4.8×Si?0.8×Sn?P+0.5×Pb?61.5; and 0.09?f3=P/Sn?0.30. The area percentage (%) of respective constituent phases satisfies the following relations: 30???65; 0???2.0; 0???0.3; 0???2.0; 96.5?f4=?+?; 99.4?f5=?+?+?+?; 0?f6=?+??3.0; and 35?f7=1.05×?+6×?1/2+0.5×??70. ? phase is present in ? phase, the long side of the ? phase is at most 50 ?m, and the long side of the ? phase is at most 25 ?m.

Abstract: This free-cutting copper alloy contains Cu: more than 57.5% but less than 64.5%, Si: more than 0.20% but less than 1.20%, Pb: more than 0.001% but less than 0.20%, Bi: more than 0.10% but less than 1.00%, and P: more than 0.001% but less than 0.20%, with the balance being Zn and unavoidable impurities, wherein the total amount of Fe, Mn, Co and Cr is less than 0.45%, the total amount of Sn and Al is less than 0.45%, relationships of 56.3?f1=[Cu]?4.8×[Si]+0.5×[Pb]+0.5×[Bi]?0.5×[P]?59.5 and 0.12?f2=[Pb]+[Bi]<1.0 are satisfied.

Abstract: This free-cutting copper alloy includes Cu: more than 58.0% and less than 65.0%, Si: more than 0.30% and less than 1.30%, Pb: more than 0.001% and 0.20% or less, Bi: more than 0.020% and 0.10% or less, and P: more than 0.001% and less than 0.20%, with the remainder being Zn and unavoidable impurities, a total amount of Fe, Mn, Co and Cr is less than 0.45%, a total amount of Sn and Al is less than 0.45%, relationships of 56.5?[Cu]?4.7×[Si]+0.5×[Pb]+0.5×[Bi]?0.5×[P]?59.5, and 0.025?[Pb]+[Bi]<0.25 are satisfied, in constituent phases of a metallographic structure, relationships of 20?(?)<85, 15<(?)?80, 0?(?)<5, 8.0?([Bi]+[Pb]?0.002)1/2×10+([P]?0.001)1/2×5+((?)?7)1/2×([Si]?0.1)1/2×1.2+(?)1/2×0.5?17.0, and 0.9?([Bi]+[Pb]?0.002)1/2×((?)?7)1/2×([Si]?0.1)1/2?4.0 are satisfied, and a particle containing Bi is present in ? phase.

Abstract: This free-cutting copper alloy contains more than 77.0% but less than 81.0% Cu, more than 3.4% but less than 4.1% Si, 0.07% to 0.28% Sn, 0.06% to 0.14% P, and more than 0.02% but less than 0.25% Pb, with the remainder being made up of Zn and unavoidable impurities. The composition satisfies the following relations: 1.0?f0=100×Sn/(Cu+Si+0.5×Pb+0.5×P?75.5)?3.7, 78.5?f1=Cu+0.8×Si?8.5×Sn+P+0.5×Pb?83.0, 61.8?f2=Cu?4.2×Si?0.5×Sn?2×P?63.7. The area ratios (%) of the constituent phases satisfy the following relations, 36???72, 0???2.0, 0???0.5, 0???2.0, 96.5?f3=?+?, 99.4?f4=?+?+?+?, 0?f5=?+??3.0, 38?f6=?+6×?1/2+0.5×??80. The long side of the ? phase does not exceed 50 ?m, and the long side of the ? phase does not exceed 25 ?m.

Abstract: This free-cutting copper alloy includes Cu: more than 61.0% and less than 65.0%, Si: more than 1.0% and less than 1.5%, Pb: 0.003% to less than 0.20%, and P: more than 0.003% and less than 0.19%, with the remainder being Zn and unavoidable impurities, a total content of Fe, Mn, Co, and Cr is less than 0.40%, a total content of Sn and Al is less than 0.40%, a relationship of 56.5?f1=[Cu]?4.5×[Si]+0.5×[Pb]?[P]?59.5 is satisfied, constituent phases of a metallographic structure have relationships of 20?(?)?80, 15?(?)?80, 0?(?)<8, 18×(?)/(?)<9, 20?(?)1/2×3+(?)×([Si])1/2?88, and 33?(?)1/2×3+(?)×([Si])1/2+([Pb])1/2×35+([P])1/2×15, and a compound including P is present in ? phase.

Abstract: This free-cutting copper alloy contains Cu: 58.5 to 63.5%, Si: more than 0.4% and 1.0% or less, Pb: 0.003 to 0.25%, and P: 0.005 to 0.19%, with the remainder being Zn and inevitable impurities, a total amount of Fe, Mn, Co and Cr is less than 0.40%, a total amount of Sn and Al is less than 0.40%, a relationship of 56.3?f1=[Cu]?4.7×[Si]+0.5×[Pb]?0.5×[P]?59.3 is satisfied, constituent phases of a metal structure have relationships of 20?(?)?75, 25?(?)?80, 0?(?)<2, 20?(?)1/2×3+(?)×(?0.5×([Si])2+1.5×[Si])?78, and 33?(?)1/2×3+(?)×(?0.5×([Si])2+1.5×[Si])+([Pb])1/2×33+([P])1/2×14, and a compound including P is present in ? phase.

Abstract: This high-strength free-cutting copper alloy comprises 75.4-78.0% Cu, 3.05-3.55% Si, 0.05-0.13% P and 0.005-0.070% Pb, with the remainder comprising Zn and inevitable impurities, wherein the amount of Sn existing as inevitable impurities is at most 0.05%, the amount of Al is at most 0.05%, and the total amount of Sn and Al is at most 0.06%. The composition satisfies the following relations: 78.0?f1=Cu+0.8×Si+P+Pb?80.8; and 60.2?f2=Cu?4.7×Si?P+0.5×Pb?61.5. The area percentage (%) of respective constituent phases satisfies the following relations: 29???60; 0???0.3; ?=0; 0???1.0; 98.6?f3=?+?; 99.7?f4=?+?+?+?; 0?f5=?+??1.2; and 30?f6=?+6×?1/2+0.5×??62. The long side of the ? phase is at most 25 ?m, the long side of the ? phase is at most 20 ?m, and the ? phase is present within the ? phase.

Abstract: This free-cutting copper alloy contains 76.0%-79.0% Cu, 3.1%-3.6% Si, 0.36%-0.84% Sn, 0.06%-0.14% P, 0.022%-0.10% Pb, with the remainder being made up of Zn and unavoidable impurities. The composition satisfies the following relations: 74.4?f1=Cu+0.8×Si?8.5×Sn+P+0.5×Pb?78.2, 61.2?f2=Cu?4.4×Si?0.7×Sn?P+0.5×Pb?62.8, 0.09?f3=P/Sn?0.35. The area ratio (%) of the constituent phases satisfies the following relations: 30???65, 0???2.0, 0???0.3, 0???2.0, 96.5?f4=?+?, 99.4?f5=?+?+?+?, 0?f6=?+??3.0, 36?f7=1.05×?+6×?1/2+0.5×??72. The ? phase is present within the ? phase, the long side of the ? phase does not exceed 50 ?m, and the long side of the ? phase does not exceed 25 ?m.