Abstract: To contribute to an improvement in a dezincification resistance of a copper alloy, focusing attention on a relation between a dezincification resistance of a copper alloy and the crystal grain size of an ? phase, and the specific object is to provide a method of producing a hot forged product using a lead-free brass capable of ensuring corrosion resistances such as a prescribed dezincification resistance and the like even at sites of different thickness and shape, a hot forged product, and a wetted product such as a valve and a water faucet, molded using the same. A method of producing a hot forged product using a brass, comprising heat-treating a raw material to be subjected to forging work using a brass having a composition containing at least 59.2 to 63.0% by mass of Cu, 1.00 to 2.00% by mass of Sn and 0.05 to 0.25% by mass of Pb and containing the residue composed of Zn and inevitable impurities at a heating rate of 5.2° C./s or more from 350° C. until reaching the forging temperature.

Abstract: By enhancing a stress corrosion cracking resistance in a leadless brass alloy, specifically by suppressing a velocity of propagation of corrosion cracks in the brass alloy, a straight line crack peculiar to the leadless brass alloy is suppressed, a probability of cracks coming into contact with ? phases is heightened and local corrosion on the brass surface is prevented to suppress induction of cracks by the local corrosion, thereby providing a leadless brass alloy contributable to enhancement of the stress corrosion cracking resistance. The present invention is directed to an Sn-containing Bi-based, Sn-containing Bi+Sb-based or Sn-containing Bi+Se+Sb-based leadless brass alloy excellent in stress corrosion cracking resistance, having an ?+? structure or ?+?+? structure and having ? phases distributed uniformly therein at a predetermined proportion to suppress local corrosion and induction of stress corrosion cracks.

Abstract: To contribute to an improvement in a dezincification resistance of a copper alloy, focusing attention on a relation between a dezincification resistance of a copper alloy and the crystal grain size of an ? phase, and the specific object is to provide a method of producing a hot forged product using a lead-free brass capable of ensuring corrosion resistances such as a prescribed dezincification resistance and the like even at sites of different thickness and shape, a hot forged product, and a wetted product such as a valve and a water faucet, molded using the same. A method of producing a hot forged product using a brass, comprising heat-treating a raw material to be subjected to forging work using a brass having a composition containing at least 59.2 to 63.0% by mass of Cu, 1.00 to 2.00% by mass of Sn and 0.05 to 0.25% by mass of Pb and containing the residue composed of Zn and inevitable impurities at a heating rate of 5.2° C./s or more from 350° C. until reaching the forging temperature.

Abstract: By enhancing a stress corrosion cracking resistance in a leadless brass alloy, specifically by suppressing a velocity of propagation of corrosion cracks in the brass alloy, a straight line crack peculiar to the leadless brass alloy is suppressed, a probability of cracks coming into contact with ? phases is heightened and local corrosion on the brass surface is prevented to suppress induction of cracks by the local corrosion, thereby providing a leadless brass alloy contributable to enhancement of the stress corrosion cracking resistance. The present invention is directed to an Sn-containing Bi-based, Sn-containing Bi+Sb-based or Sn-containing Bi+Se+Sb-based leadless brass alloy excellent in stress corrosion cracking resistance, having an ?+? structure or ?+?+? structure and having ? phases distributed uniformly therein at a predetermined proportion to suppress local corrosion and induction of stress corrosion cracks.

Abstract: A copper-based alloy essentially includes 5.0 to 10.0 wt % of Zn, 2.8 to 5.0 wt % of Sn, 0.4 to 3.0 wt % of Bi, 0<Se?0.35 wt %, 0<P?0.5, one of 0<Sb?2.2 wt % and 0<Ni?4.8 wt %, and a balance of Cu and unavoidable impurities. It may essentially includes 5.0 to 10.0 wt % of Zn, 2.8 to 5.0 wt % of Sn, 0.4 to 3.0 wt % of Bi, 0?Se?0.35 wt %, 0<P<0.5 wt %, one of 0<Sb?2.2 wt % and 0<Ni?4.8 wt %, 1.20 to 4.90 Vol. % of at least one selected from the group consisting of a non-solid solution substance secured with Bi and a non-solid solution secured with Bi and Se, and a balance of Cu and unavoidable impurities.

Abstract: A copper-based alloy that has the soundness of alloy enhanced by restraining the concentrated occurrence of microporosities while suppressing the lead content and an ingot and a liquid-contacting part using the alloy are provided. The copper-based alloy has the soundness of alloy improved during the course of solidification of the copper-based alloy by crystallizing an intermetallic compound capable of solidifying at a temperature exceeding a solidus line in dendritic gaps of the alloy, suppressing migration of a solute, thereby allowing dispersion of microporosities, utilizing crystallization of the intermetallic compound as well for effecting dispersed crystallization of a low melting metal or a low melting intermetallic compound capable of solidifying at a temperature falling short of a liquidus line, and relying on the low melting metal or low melting intermetallic compound to enter the microporosities and suppress occurrence of microporosities.

Abstract: By enhancing a stress corrosion cracking resistance in a leadless brass alloy, specifically by suppressing a velocity of propagation of corrosion cracks in the brass alloy, a straight line crack peculiar to the leadless brass alloy is suppressed, a probability of cracks coming into contact with ? phases is heightened and local corrosion on the brass surface is prevented to suppress induction of cracks by the local corrosion, thereby providing a leadless brass alloy contributable to enhancement of the stress corrosion cracking resistance. The present invention is directed to an Sn-containing Bi-based, Sn-containing Bi+Sb-based or Sn-containing Bi+Se+Sb-based leadless brass alloy excellent in stress corrosion cracking resistance, having an ?+? structure or ?+?+? structure and having ? phases distributed uniformly therein at a predetermined proportion to suppress local corrosion and induction of stress corrosion cracks.

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.

Abstract: This invention has for an object thereof the provision of a leadless copper-based alloy which mends the deterioration of tensile strength at elevated temperatures and enables the mechanical properties thereof to approximate the CAC406 by forming in the alloy texture thereof an alloy or an intermetallic compound with Bi and Pb existing independently or in a mutually joined state. For the purpose of accomplishing the object, this invention incorporates in the copper-based alloy an additive element capable of forming an alloy or an intermetallic compound with Bi and Pb existing independently or in a mutually joined state. The additive element is one or more members selected from the group consisting of Te, P, Zr, Ti, Co, In, Ca, B and misch metal.

Abstract: By exactly comprehending the true properties of the rare elements (such as Bi and Se) which are alternative components for Pb, the alloy is enabled to secure machinability equal to the bronze alloy (CAC406) generally used hitherto and acquire mechanical properties at least equal to the CAC406 as well in spite of a decrease in the content of the rare elements (such as Bi and Se) in the alloy. Further, it is possible to suppress the occurrence of casting defects by elucidating the unresolved influence of the decrease of the alternative components (such as Bi and Se) for Pb on the wholesomeness of a casting. Moreover, it is possible, by decreasing the rare elements, to produce a copper-based alloy containing rare elements at a low cost and to provide a cast ingot and a liquid-contacting part each using the alloy. The copper-based alloy, and the cast ingot and liquid-contacting part each using the alloy individually contain at least 2.8 to 5.0 wt % of Sn, 0.4 to 3.0 wt % of Bi and satisfying 0<Se?0.

Abstract: A copper-based alloy essentially includes 5.0 to 10.0 wt % of Zn, 2.8 to 5.0 wt % of Sn, 0.4 to 3.0 wt % of Bi, 0<Se?0.35 wt %, 0<P?0.5, one of 0<Sb?2.2 wt % and 0<Ni?4.8 wt %, and a balance of Cu and unavoidable impurities. It may essentially includes 5.0 to 10.0 wt % of Zn, 2.8 to 5.0 wt % of Sn, 0.4 to 3.0 wt % of Bi, 0?Se?0.35 wt %, 0<P<0.5 wt %, one of 0<Sb?2.2 wt % and 0<Ni?4.8 wt %, 1.20 to 4.90 Vol. % of at least one selected from the group consisting of a non-solid solution substance secured with Bi and a non-solid solution secured with Bi and Se, and a balance of Cu and unavoidable impurities.

Abstract: A copper-based alloy that has the soundness of alloy enhanced by restraining the concentrated occurrence of microporosities while suppressing the lead content and an ingot and a liquid-contacting part using the alloy are provided. The copper-based alloy has the soundness of alloy improved during the course of solidification of the copper-based alloy by crystallizing an intermetallic compound capable of solidifying at a temperature exceeding a solidus line in dendritic gaps of the alloy, suppressing migration of a solute, thereby allowing dispersion of microporosities, utilizing crystallization of the intermetallic compound as well for effecting dispersed crystallization of a low melting metal or a low melting intermetallic compound capable of solidifying at a temperature falling short of a liquidus line, and relying on the low melting metal or low melting intermetallic compound to enter the microporosities and suppress occurrence of microporosities.

Abstract: This invention has for an object thereof the provision of a leadless copper-based alloy which mends the deterioration of tensile strength at elevated temperatures and enables the mechanical properties thereof to approximate the CAC406 by forming in the alloy texture thereof an alloy or an intermetallic compound with Bi and Pb existing independently or in a mutually joined state. For the purpose of accomplishing the object, this invention incorporates in the copper-based alloy an additive element capable of forming an alloy or an intermetallic compound with Bi and Pb existing independently or in a mutually joined state. The additive element is one or more members selected from the group consisting of Te, P, Zr, Ti, Co, In, Ca, B and misch metal.

Abstract: By exactly comprehending the true properties of the rare elements (such as Bi and Se) which are alternative components for Pb, the alloy is enabled to secure machinability equal to the bronze alloy (CAC406) generally used hitherto and acquire mechanical properties at least equal to the CAC406 as well in spite of a decrease in the content of the rare elements (such as Bi and Se) in the alloy. Further, it is possible to suppress the occurrence of casting defects by elucidating the unresolved influence of the decrease of the alternative components (such as Bi and Se) for Pb on the wholesomeness of a casting. Moreover, it is possible, by decreasing the rare elements, to produce a copper-based alloy containing rare elements at a low cost and to provide a cast ingot and a liquid-contacting part each using the alloy. The copper-based alloy, and the cast ingot and liquid-contacting part each using the alloy individually contain at least 2.8 to 5.0 wt % of Sn, 0.4 to 3.0 wt % of Bi and satisfying 0<Se?0.