Four kinds of dezincification corrosion resistance brass castings (JIS symbols CAC211, CAC221, CAC231, and CAC232) and two kinds of Bismuth bronze castings (JIS symbols CAC905 and CAC906) were suggested to Japanese Industrial Standards (JIS H2210, H5120 and H5121) as alloys applicable to tools related to water supply appliances. For the corrosion-resistant evaluation of these six new alloys (proposed new materials), dezincification-corrosion test (ISO 6509-1981), erosion-corrosion test (jet-in-slit test) and stress-corrosion-cracking test were carried out, and the results were compared with JIS copper alloys (CAC203, CAC804, CAC902, and C3771). The dezincification corrosion resistance of the proposed materials was better than CAC203 and equal to CAC804 and CAC902. In the erosion-corrosion test of the JIS copper alloys, CAC902 was excellent, followed by CAC804, C3771, and CAC203 (CAC902 >> CAC804 > C3771 > CAC203) in this order. Among the proposed alloys, CAC211, CAC231, CAC905, and CAC906 showed good erosion-corrosion resistance equal to CAC902. The erosion-corrosion resistance of CAC221 and CAC232 was worse than CAC902 and equal or slightly better than CAC804. In addition, it was revealed that the erosion-corrosion resistance improved when tin was contained. In the stress-corrosion-cracking test, the stress-corrosion-cracking sensitivity of the proposed materials was lower than C3771 and CAC203.

  The influence of Sn addition on castability, mechanical properties, and corrosion resistance of silzin bronze castings JIS CAC804 was investigated. The results showed that the solidus point and liquidus point are lowered by Sn addition and the solidification temperature range is wide. Generally, castability is poor when the solidification temperature range is wide, but there were no significant differences between CAC804 and Sn-added CAC804. Moreover, grain refinement during melt-solidification decreases casting defects like shrinkage cavities.

  The added Sn transforms the solid solution into the γ phase, and decreases ductility. Although the results of erosion corrosion tests differ according to test conditions, it is clear that Sn addition decreases the weight of CAC804 in erosion corrosion tests under the two different conditions.

  Lead-free bronze castings dispersed with sulfide particles, whose main composition is the same as JIS CAC411, and which contains over 0.05mass% phosphorus as a residual element, were prepared. Tensile test, fluidity test, microstructure test, and pressure toughness test of the lead-free bronze castings were carried out. Results of tensile tests on JIS CAC406 castings, which are used as common bronze castings, show that the elongation of some specimens containing over 0.05mass% phosphorus is below the JIS requirement of 15%. In contrast, the elongation of the lead-free bronze castings with dispersed sulfide particles was over 15% even when phosphorus content was increased to about 0.1mass%. Increasing the phosphorus content improves the fluidity of the lead-free bronze castings and realizes excellent pressure toughness. In addition, the results of measurement of elemental distribution by EPMA reveal the presence of regions composed of phosphorus and nickel near the sulfide particles. This suggests that a certain amount of phosphorus exists as a compound composed of phosphorus and nickel.

  A new pouring equipment for measuring the fluidity of the copper alloys was developed. The developed equipment consists of a pouring cup system with high heat-retaining property, stopper system requiring no preheating, and pouring temperature determination system. In the evaluation of the developed equipment, the temperature of the molten copper alloy decreased by 30K from tapping until the measurement of the molten alloy temperature in the pouring cup stabilized. The temperature decreasing rate of the molten copper alloy in the pouring cup until the pouring temperature was 3.5K/s. The experimental results showed that the linearity between the superheat of the melt and fluidity improved compared with that found in previous studies, and the standard deviation of the fluidity in the equipment was 20mm. These results indicate that the effects of the casting conditions on the fluidity of copper alloys have been evaluated accurately with the developed equipment.

  The age-hardening behavior and low friction characteristics of Cu-Sn-Bi alloy with 1.5mass% nickel and 0.3mass% sulfur (PBX alloy) have been investigated.

  The PBX alloy showed age-hardening when aged at the temperature range of 673K to 743K for over 0.6ks after solution treatment at α ＋ γ stable temperature. Peak hardness was obtained by aging at 673K. After aging at the temperature range of 573K to 743K, the supersaturated solid solution part changed into eutectoid structure in which fine δ precipitated. The age-hardening of the PBX alloy showed a two-step hardening. The first step began within 0.6ks and then hardness increased slowly with aging time. Aged at 673K, the eutectoid matrix changed into a pine needle-shaped structure. The structure is a mixed structure of a bainitic structure and quasi-martensite having mid-rib structures in several places. Aged at 743K, the macro crystal grain size did not change in 3.6ks, but aging over 14.4ks caused macro crystal grain refinement. The dynamic friction coefficient of the PBX alloy in an oil bath of 333K was smaller than that of CAC603 alloy due to the eutectoid structure of the α phase and fine δ phase.