The effects of working temperature and of subsequent annealing on the mechanical properties have been investigated for mild steel. The specimens were deformed at temperatures between 100° and 700°C, and then their hardness, static tensile properties and impact values were measured at the room temperature
The maximum work-hardening effect was observed at temperatures of the bluing region, and the higher the working temperature the higher the impact value.
The specimens cold-worked at temperatures below about 400°C were still more hardened and strengthened by subsequent low temperature annealing, and maximum strength and hardness were obtained by cold-working at 350°C and then annealing at 350°C for 30min.

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The measuring error of the depression has a large influence upon the hardness which is calculated by the area of depression.
The author studied the surface indented by Brinel, Vickers and Knoop depressions using Ogoshi Surface Roughness Tester, and found that for the same metal the piling-up was almost constant regardless of the applied weight and the measuring error, i. e. the error of hardness, differs with the metal. It was also found that there was a slight piling-up in the diagonal of Vickers depression but no piling up in the major diagonal of Knoop depression.

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We observed the tool failure of three different kinds of cemented carbide tool in cutting plain cast iron. Weld was created at low speed on any tool, and some different types of tool failure were found at higher speed, that is, the tool with fine WC showed a rectangular type flank wear with deep crater and the coarse showed a triangular type with shallow crater. It being difficult to get the preferable rectangular type by cuttring such brittle cast iron, it is desirable that abnormal chipping does not appear. In this respect, the grade with both fine and coarse grains was preferable to the others.
Among the other factors affecting the failure, it was found that too small feed and relief angle accelerated the flank wear.

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The high manganese steel containing 0.8 to 1.3% C and 10 to 14% Mn is generally used for the wear resisting steel which is very tough if it is treated by the so-called water toughening.
Devising a tube-mill type abrasion tester we performed abrasion tests on high manganese steels of various components, and an outline of the results is given in this paper.
As we know that the initial grain size of the austenite has a greater effect on the wear resisting property of the material than other chemical components such as Mn, C and etc. and that the steel of large grain size is inferior to the steel of small grain size in the near resisting property, we shonld pay strict attention to the factors controlling the grain size in manufacturing steel. When the size of the grain is nearly equal, steel contaming about 12% Mn is in general most resistive against wear in the experimental scope.

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Sp. Surface area of powder can be easily determined in any case by Blain's method, but this method has the following defects.
(1) Amendment must be made with a standard sample of a known sp. surface area.
(2) In measuring the sp. surface area of powder other than portland cement, silica cement and slag cement, the value of the porosity to be adopted is not clearly defined.
A new method of determining the sp. surface area not containing the above defects is proposed using Blains apparatus and the variation of the values of the sp. surface area was researched by changing the porosity. The result was that for powder consisting mainly of simple macro particles the value of the sp. surface area was, within the experimental error, always constant even if the porosity is changed considerably.

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