X-ray diffraction tests and measurments of the micro-hardness distribution were carried out on impact test pieces of carbon steel fractured at various temperatures. The observations of the X-ray diffraction patterns of the fractured surfaces showed that plastic deformation always occured at the fractured surfaces, even if the fracture was of a cleavage type. However the amount of the plastic deformation of a fully embrittled piece was very small and was considered to correspond to that of about 1% elongation in a simple tension test. A difference of the hardness distribution between the surface and the interior was observed when the test pieces were fractured at higher temperatures. However the degree of the difference became low when the test piece was fractured at a lower temperature, and we could not measure the increase of hardness near the fractured surface of the test piece fractured at the lowest temperature. This indicates the effect of the plastic deformation is limited within a very thin layer of the fractured surface.
The purpoes of this study is the analysis of iron-carbon-nitrogen ternary alloy. In this report, samples of pure iron were cyanided under various conditions and some of these were tempered, and the changes of the cases were measured by differential thermal dilatation, X-ray diffraction, microstructure, micro-Vicker’s hardness, and chemical analysis tests.
In testing case-hardened steel, it is essential that the depth of the case be sufficient to suport the penetrator properly. The author tested the hardness of carburizing case-hardened steel by using Rockwell, Shore and Vickers hardness tester. As a result of this test, it was found that the effective case-depth and the total case-depth should be about ten times and twelve times the depth of indentation respectively. Then the author proposes a non-destructive method for measuring the case-depth of carburized steel by applying Meyer’s law.
Using miniature impact specimens of round bars, the temper-brittleness has been studied on a Si-Cr-Mn structural steel. The impact tests by this miniature round bar specimens had sufficient sensitivity in the measurements of transition temperature, but the transition temperature was found to be about 70°C lower than that of standard Charpy test pieces. Above 550°C, the higher the tempering temperature, the larger the differences in the transition temperature due to the different cooling rate after tempering. This fact was principally due to the pronounced lowering in the transition temperature when the specimens were cooled down rapidly from the higher tempering temperature. Furthermore, isothermal embrittlement of specimens as cooled rapidly after tempered at 650° has been made at various temperatures up to 600°C and the variation of transition temperatures was compared. Since Si-Cr-Mn steel showed remarkable temper-brittleness, its transition temperature has been shifted up about 240°C by reheating at 500°C for 100 hrs.
The chemical reactions of siliconizing of steel with silicon tetrachloride atmospheres were investigated. The effects of gas flow rate, temperature and time on weight change differed, whether the atmosphere was a reducing gas as hydrogen or neutral gas. The reaction rate of siliconizing of steel showed a discontinuity near 900°, and decreased rapidly by compound formation. On thermodynamic data of reactions between iron and silicon tetrachloride, the experimental results were discussed.
The sides of disk-like specimens made of 5%Cr-Mo-Si steel were repeatedly heated and cooled by using a high-frequency induction surface-hardening apparatus, and the influence of heating time and heating temperature on the formation of heat-checks on the sides was studied. The results were as follows: (1) The longer the heating time (t) and the higher the heating temperature (surface temperature θ), the more conspicuous the checks. This tendency is more apparent in the case of N(the number of thermal cycles)=1000 than N=100. (2) In the case of N=1000, the mean depth and the maximum depth of checks increase with increasing heating times and heating temperature, but the total number of checks reaches a maximum at t=2.5 sec (θ=850°) and decreases at t=3.0 sec (θ=910°). (3) The depth of checks at any heating time is distributed according to the exponential function, but in the case of t=3.0 sec the distribution is changed showing a lesser number of shallow checks. (4) With increasing heating time and heating temperature, the width of the checks on the cross-section of the specimen also increases.
The author has studied the effect of the carbon content on the resistance to annealing, using three samples of carbon steel wires (carbon content: 0.62, 0.80 and 1.08%). The results obtained were as follows: (1) The tempering temperature of non-breakage at breaking-angle tests: The temperature was the lowest with 0.62% carbon steel and the highest (above 450°) with 1.08% carbon steel wire. (2) The change of irregularity of breaking angle due to tempering: The largest with 0.62% and the smallest with 1.08% carbon steel. (3) The maximum strength is obtained when 1.08% carbon steel is austeniged ununiformly and the minimum when the same is austenized uniformly. These results show that high carbon steel is affected by heat-treatment delicately and extensively.
Photometric determination of titanium in metallic aluminium and its alloys were carried out by using sodium alizarinsulfonate and stannous chloride in acidic solution of hydrochloric aicd. The time required until the absorbance reaches constant, were about 60 min at 18° of sample solution and its absorbance held constant in about 30 min and then decreased little by little. By this method 0.002∼0.2 per cent of titanium could be determined correctly.
Experiments show that the so-called peritectic structure always appears in all peritectic alloys which have the condition of ‾LS⁄‾SP>I for the relative position of the three phases on the peritectic line and doesn’t appear in ‾LS<‾SP peritectic alloys. The author has discovered that this phenomen depends on the course of the peritectic reaction which results from the diagrammatical meaning of ‾LS⁄‾SP value, and suggested a mechanism of the course of the peritectic reaction from the above mentioned fact. The characteristics of the peritectic reaction which occurs in the binary system can be deduced from the experimental results.
Some data on zone-melting were deduced with ordinary alloys, such as Al-Cu system, having a segregation coefficient of about 0.15. The results were compared with the theoretical curves obtained from Norman W. Lord’s formula. It was seen that the results greatly deviated from the theoretical curve, i.e. the number of molten-zone passage, the zone length and the rate of moving molten zone remarkably influenced the purification degree. Therefore, a further refining might be achieved by repeating the zone passage, or by moving it slowly, or by making the zone narrow. On the other hand, with increasing number of zone passage, or with decreasing rate of zone moving, the purified range decreased, and the starting edge of the molten-zone was not refined.
The variation of the integrated intensities and breadths of (111), (200), (220) and (113) Cu-Kβ diffraction lines from commercially pure copper and high-purity silver in the processes of cold-rolling and annealing were observed by means of a counter-diffractometer by the Bragg-Brentano para-focusing method. The following results have been obtained. (1) In the case of Cu, the volume of crystals having their (110) plane parallel to the rolling plane increases by rolling, but has a weak maximum at about 91% reduction and decreases slightly on higher reductions. However, in the case of Ag, it shows no maximum point within the reduction of 96.9%. (2) In both Cu and Ag, only a slight part of crystals having their (100) or (113) plane parallel to the rolling plane remains after about 97∼99% reduction. (3) In the case of Ag, crystals having their (111) plane parallel to the rolling plane increase by cold-rolling, showing a maximum at about 90% reduction. (4) On annealing 98.9%-rolled copper sheets at 200° for 2∼5 minutes, a cubically aligned texture developes rapidly, while (110)-orientation decreases at a smaller rate. (5) During the development of the cubically aligned texture, the integrated breadths of (200) and (220) diffraction lines were observed to decrease gradually at a corresponding rate resulting from the relief of lattice strain and the growth of particles.
The variation of the integrated intensities and breadths of X-ray diffraction lines from polycrystalline high-purity aluminium in the processes of cold-rolling and annealing were observed by means of a counter-diffractometer by the Bragg-Brentano para-focusing system. The following results have been obtained: (1) Crystals having their (110) plane parallel to the rolling plane increase by rolling, but after having reached a maximum volume at a medium reduction, decrease on further reductions. (2) In the region near the surface of the specimen, crystals having their (111) plane parallel to the rolling plane decrease conspicuously by cold-rolling and only a few percent of them remain at about 70% and higher reductions. (3) Crystals having their (113) or (112) plane parallel to the rolling plane increase remarkably at high reductions. (4) On annealing at 100∼200°, the integrated breadth of each diffraction line was almost unchanged, but many small discrete diffraction spots could be observed by the usual photographic method. At this stage, the (100) and (113) orientations, developed by rolling, have a tendency to decrease, while the (110) orientation increases. (5) On annealing at temperatures higher than 300°, a cubically aligned texture developes very rapidly, while the (110), (112) and (113) orientations decrease at a smaller rates. During this process, the integrated breadths were observed to decrease.
The author herein proposes a theory on the mechanism of the interaction between a dislocation and the atomic order, which is based on the coupling of the stress field of dislocation with the lattice distortion accompanied by ordering in superlattice alloys. The interaction energy and the locking force of the atomic configuration around the dislocation against its motion are calculated by using Iwata’s method. The interaction energy and the locking force for an edge dislocation reveals a sharp peak at the temperature near the Curie point of order-disorder transformation, while such a sharp peak is absent in a screw dislocation. The values for a screw dislocation is about 1∼10% of those for an edge dislocation.