This Cooperated study was conducted by the sub-committee of the Copper-Base Alloy Castings of the Japan Foundrymen's Society with the purpose of determining the possible mechanical properties of the specified tensile test bars and substantial mechanical properties of foundry products in the copper-base alloys. The subject alloys were yellow brasses, high-strength yellow brasses, tin bronzes, leaded gunmetals, phosfur bronzes and aluminum bronzes which are specified in the Japan Industrial Standards (JIS). All the test castings were prepared in the commercial foundries.
  The experiment includes the following items :
  1. Determination of the mechanical properties of the JIS tensile test bars.
     a) Mechanical properties the JIS test bars.
     b) Effect of the pouring temperature on the properties of the JIS test bars.
     c) Effect of the heat treatment on the mechanical properties of aluminum bronzes (AlBC 2 and 3).
     d) Mechanical properties of the JIS and green sand molded test bars in the tin bronzes (BC 2 and 6) and phosfur bronzes (PBC 1 and 2).
     e) Mechanical properties of the shell molded test bars in the yellow brasses, tin bronzes, phosfur bronzes and aluminum bronzes.
  2. Determination of the substantial mechanical properties of the foundry products.
     a) Relation between the mechanical proprerties and wall thickness of the stepped casting.
     b) Effect of the pouring temperature on the mechanical properties of the stepped casting.
     c) Effect the gating system and/or of feeding direction on the mechanical properties and their distribution in the L-sectioned castings with various wall thickness.
  The JIS test bars in all the alloy systems have mechanical properties well over the specification limits provided that appropriate melting and pouring are made. The subject alloys are classified into two groups on the basis of the mode of solidification; i) long freezing range type, in which tin bronzes, gunmetals and phosfur bronzes belong, and ii) skin formation type, in which yellow brasses, high-strength yellow brasses and aluminum bronzes belong. In the former the mechanical properties are so susceptible that each alloy system has the optimum pouring temperature in itself, but in the latter they are not so susceptible. The alloy castings in the former are also susceptible to the wall thickness and feeding direction, while that in the latter are not so.
  Details of each alloy system are described in the succeeding papers respectively.

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  The mechanical properties of the tensile test bars in the yellow brasses (JIS. BsC 1, 2, 3, 4 and 5) produced in commercial foundries were determined in company with the distribution of mechanical properties in the stepped and L-sectioned castings in BsC 3. All groups of the brasses havetensile properties even higher than the values specified in JIS. Little reasonable differance in themechanecal properties is found in the dry sand, green sand and shell molded cast bars. In the stepped and L-sectioned castings the mechanical properties are not quite susceptible to the thickness, location in the casting and feeding direction. This is probably a nature of the skin-formation type alloys.

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  The present paper involves the measurement of standard values of tensile test by using JIS No. 4 test bar the study on substantial tensile properties of various sections of the step formed and L formed castings concerning high strength yellow brass. The obtained standard tensile properties are as follows.
                       σв(kg/mm²)       δ(%)           B.H.N.
         HBsC 1         46∼49            30∼40        100∼120
         HBsC 2         50∼57            20∼25        120∼150
         HBsC 3         60∼65            10∼15        150∼200
  The occurrance of casting defects and the substantial strength of castings closely related to mass and position of riser, pouring temperature, cooling rate etc. In massive high strength brass castings, the tensile properties have comparatioely uniform values through-out the section and almost uniform substatial strength region appears in the internal part of the section.

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  This paper covers the mechanical properties of tensile test bars and the distribution of mechanical properties both in the stepped and L-sectioned castings in the lead-free tin bronzes (BC 2 and 3 in JIS). The mechanical properties, particularly elongation of the specified test bars are exercised to the influence of the pouring temperature. The heavier section of the stepped casting has lowered mechanical properties. Steep decrease in the mechanical properties is encountered at the corner and along the centre line of the L-sectioned casting.

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  The leaded gunmetal test bars (JIS BC 6 and 7) cast in dry sand, green sand and shell molds have superior mechanical properties over the JIS limitations. The nature of mechanical properties of the alloys is similar to that in the tin bronzes. In the stepped casting and L-type castig the thickness and feeding direction have marked influences on the properties. Heavy sections have lowered mechanical properties and up-run is more favourable than down-run. The relation between the tensile strength and the elongation is plotted from all the tensile data.

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  The tensile test bars cast into the dry sand and shell molds in the phosfur bronzes (PBC 1 and 2) have considerably scattered mechanical properties, while those cast into the metallic molds in another type of the phosfur bronze (PbC 3) show comparatively low scattering in the propreties. The mechanical properties of the stepped castings are decreased as the section thickness is increased. Marked lowering in the mechanical properties is encountered at the base of the riser and on the center line of the L-sectioned castings. The fatigue test is also described.

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  The mechanical properties of the specified tensile test bars and of the stepped and L-secctioned castings in aluminum bronzes (JIS. AlBC 1, 2 and 3) were determined. Preferable gating systems to produce the stepped and L-sectioned castings without defects were examined with radiographic technique. The castings made under those of careful conditions have a little scatter of the mechanical properties interioly and have a slight fall in the properties even in the heavy section.

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