Following the tests reported previously, the abrasion tests on high manganese steels of various components were conducted by means of a tube-mill type abrasion tester.
The results are summarized as follows:
(1) As to the effect of heat treatment on the wear resisting property of the ordinary high manganese steel, a good result is obtained in the case of 250°C tempering after quenched into water (even though there is not so much difference as compared with quenched ones), and the characteristics become worse when the tempering temperature rises to 650°C.
(2) The wear resisting property is adversely affected by adding the silicon content in the ordinary high manganese steel.
(3) And also adding of chromium content is no good for the wear resisting property.
(4) The special manufactured high manganese steel shows excellent wear resistance not-withstanding its chemical composition which is not so different from that of ordinary high manganese steel.
(5) The result reported in the previous report, that the steel of large grain size is inferior to the steel of small grain size in the wear resisting property, is applied in this case.
(6) The relation between the wearing time and the amount of wear may be formularized experimentally as the formula (1), and in this case the constants in the formula show nearly constant values regardless of the quality of each material.
(7) The relation between the wearing time and the hardness is closely connected. The formula (2), and the constants in the formula are nearly equal in each material, and agree with the previous result that the increase of hardness with wearing time is very remarkable as compared with the carbon steel.

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This investigation was planned for researching the effect of the total reduction by drawing and the low temperature annealing upon the distribution of longitudinal residual stress of 0.65%C steel wire, drawn at various reductions from 60% to 90%, with subsequent annealing in the range 150°C to 400°C. The diameter of all these wires was 1.3mm.
For the measurement of the longitudinal residual stresses existing in these small wires, present writers adopted the dissolving method by acid, that is, the outer layers of the wire were successively dissolved off by 10% NHO₃ and at each time the change of the gauge length was measured by the micro-comparator. And then that distribution of longitudinal residual stress was calculated by Heyn's formula.
The results obtained were as follows:
All wires tested had the similar distribution of longitudinal residual stress, that is tension in outer part and compression in inner part and the maximum tensile stress existed near the surface. For both wires as-drawn and annealed at 200°C or 300°C, the maximum tensile residual stress increased with total reduction by drawing up to 85%, and beyond this reduction it decreased. The release of residual stress by low temperature annealing was remarkable in case of over 300°C.
From the fatigue limits of these wires reported in 1st report, the fatigue limits of these wires, on the assumption that there were no residual stresses, were calculated with the maximum tensile residual stresses measured in this investigation. As the result of this calculation, it was clarified that the maximum value of decreasing of the fatigue limit under rotating bending affected by the longitudinal tensile residual stress was found in the 85% reduced wire.

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The heat treated plain carbon steel, which has been subjected to the tension or the compression load below the yield point, shows various residual strain after unloading, according to the heat treatment conditions, and the author measured the value with the electric resistance wire strain gauge. The amount of this strain is about 10^-5. Especially, in the case of tempering at 300°C after quenching, the residual strain appears in the opposite direction to the applied load.
In this experiment, first, the author measured the residual strain of the specimens, which were tempered at 300°C, changing the mode of tensile load and the specimens' diameter. Next, he measured the residual strain of various specimens, which were quenched and tempered at different temperature and subjected to the tension or the compression load. And he investigated the relation between the change of specific volume before and after the load, and the residual strain after unloading. The result shows that these residual strains have some relations with the change of specific volume to be caused by tempering.

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Fatigue strength in steel wire has recently been more emphasized than ever as an important requirement for wire ropes in general use, as well as for pre-stressed concrete wires. Many of the fatigue testing machines for wire rod in practical use are of the rotating bending type. For example, fatigue testing machines of the Haigh-Robertoson type, the Hunter type and the Schwining & Dorgerloh type are most commonly used as fatigue testing machines for wire rod. But their behavior leaves something to be desired. The designing of a testing machine which would give accurate results of the experiments and which is of simple construction has long been anticipated. In this paper the outline of a newly designed fatigue testing machine is described.
Requirements for the design of the fatigue testing machine are listed as follows:
1) The testing machine should be of the constant-load type in which the load is kept constant during the test.
2) The testing machine should be of the uniform bending type, the specimen being held as a simple beam.
3) The testing machine should be of simple design and of low cost and should be capable of measuring the bending moment with great accuracy.
4) Fatigue tests, not only at room temperature but also at high or low temperature, ought to be carried out by using simple apparatuses for heating or cooling.
The newly designed testing machine is designed so as to satisfy these conditions so far as possible. By using this fatigue testing machine specimens of various sizes of diameter from 2mm to 8mm can be tested. The revolutions of the motor for this machine are variable, ranging from 500rpm to 10000rpm without step.
From the results of experiments and consideration it is concluded that the newly designed fatigue testing machine is quite excellent as a fatigue testing machine for wire rod. The main advantages of this testing machine consist in its simplicity of design, its low cost, the accuracy with which the bending moment can be measured and its high speed of operation.

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The rate and saturation value of water absorption were determined for nylon plastics molded in different shapes by injection molding. The degrees of crystallinity and its distribution in the specimens were estimated.
The change of dielectric properties caused by water absorption and the degree of crystallinity were measured in a frequency, ranging from 50KC/sec to 20MC/sec. Behavior of the absorbed water and mechanism of polarization were discussed.
The results are summarized as follows:
1) Water absorption gets larger in the order of nylon 610, 66, 6, 6/66 copolymer, and decreases by containing some additives such as graphite or metal powder.
2) Water content of nylon is proportional to the 0.4-0.5th power of time, independent of the kind of nylon, the shape of specimen, the relative humidity, etc.
3) The average degree of crystallinity gets smaller in the order of nylon 66 (37.8%), nylon 610 (30.4%), nylon 6 (24.7%).
4) The dielectric properties of nylon containing water are in non-linear relation with water content.
5) At a definite temperature and a definite degree of crystallinity, the higher the water content is, the smaller the internal friction for polar groups to orientate, which the internal friction for polar groups becomes larger with the increase of crystallinity.

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