Water content of green mold sand was determined rapidly by drying the sand in a current of warm air, allowing complete drying in about five minutes. The most appropriate water content was found, and from this knowledge estimation of water content in the foundry by hand grabbing was tried.

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  Relations between fluctuations of values of hardness measured on finished surfaces of cast iron and the roughness of that surfaces indicated by the maximum height of profilecurves recorded by a optical lever type profilometer are measured using four hardness testers, viz., the Brinell, the Rockwell, the Shore and the Vickers. Mean-square values of fluctuations in case of the Brinell and the Rockwell are below 4% irrespective of roughnesses and those in case of the Shore and the Vickers are larger and they become more than 10% for considerably rough surfaees. Now, from the extrapolated curves of fluctuation-roughness diagram, it seems that values of hardness may fluctuate even for ideally smooth surfaces. This should be ascribed to the grossness of the grain size of each structure, i. e., the distribution of each structure are not so dense compared to the sizes of penetrators of hardness testers. We measure the microhardness of each structure by Lips' method and get the values for pearlite 200～300kg/mm², ferrite 100～180kg/mm² and graphite less than 30kg/mm². Finally, the differences of values of hardness according to machining methods of surfaces are measured by the above four testers. The values differ little in case of the Brinell and the Rockwell as their penetrators penetrate deeper than the work hardened surface layer, while in case of the Shore and the Vickers large differences are observed.

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