The hardness as well as the thickness of chromium plating film appeared less in sequence of the circumferential part the ends of the middle part and the center part and a 6 hrs plating produced the hardness of 1067,1007 and 964, respectively, the difference amounting to ±8.5%. When the plating surface was however, ground and lapped (uniform accuracy : ±0.001 mm), a perfect uniform hardness was,obtained over the three parts as shown in Table 2 : the hardness of the whole surface equally became 1200±5.
The change in hardness by low-temperature annealing of cold-rolled 70/30 brasses, having different ready to-finish grain sizes (fine and coarse) and being cold-rolled by different reductions (10∼90%)was measured. The specimens were annealed at the temperatures of 150,250,350 and 450° for 5 min-24 hrs each. The hardness change by annealing is considered to be related to the structures as ready-to-finish annealed and as cold-rolled. It appears that the hardness does not vary simply with rolling reduction or grain size, but is more complicatedly influenced by the development degree of the rolling structure or by the condition of specimens such as their composition.
The structure changes by cold-rolling and low-temperature annealing of 70/30 brass were investigated by a microscope and X-ray photography. The difference in ready-to-finish grain size affects the development degree of the rolling structure. A coarse-grained material tends to delay the development, compared with a fine-grained one. The tendency is thought to be connected with the hardness change by low-temperature annealing as previously reported. No remarkable change of structure is observed by annealing at 150°, while a kind of polygonization is recognized at 250°. Though the nuclation by recrystallization develops preferentially at the regions strained severely,grain growth was observed along the slip lines at 350°. The difference in grain size affects the recrystallization process in its velocity.
The effect in the hot-dipped aluminizing process of the alloying elements found in steel and the aluminum bath on the oxidation at higth temperature was investigated. The results obtained were as follows: (1) Hot-dipped Al coatings on Si-or Cr-steel has better properties against scaling at high temperature than on plain carbon steel as a result of their own excellent heat resisting properties and a reduction of the diffusion velocity of the alloy layer. (2) Hot-dipped coatings containing Si or Be were found to be less heat-resistant than those of Al only, because the former forms thinner and more spalled alloy layers. (3) The Be-alloyed coating were found to be a little bit more heat-resistant than the Si-alloyed coating in case the alloy layers were inhibited to the same thickness. (4) In cyclic heating and cooling test, the Si-alloyed coating showed weaker adhesion to the base material than the Be-alloyed coating due to the interfacial oxide scale developed on the steel side. (5) The size of the cracks on the alloy layer becomes finer with the increase of Si or Be content. The cause of cracking is mainly due to thermal stress.
Microscopic examination of the enriched surface layers caused by oxidization of steels and the mechanism of surface fissures. The enriched layers formed on the surface of steel due to oxidization while heating and the cracks on the samples by hot-bending were examined microscopically, and the mechanism of the formation of surface fissures was investigated. The results obtained were as follows : (1) When commercial steels are heated in oxidizing atmosphere, the tramp elements in steel, such as Cu,Sn and As are steadily enriched on the surface of steel with the increase of scaling. These elements are usually dissolved in the steel matrix so long as the degree of enrichment is comparatively low, but as the enrichment is further developed, a non-ferrous liquid phase appears. It is noticed that the non-ferrous liquid phase is never found penetrating deeply into the matrix during the heating. (2) The scaling loss of samples necessary for non-ferrous liquid phase to be produced decreases as the amounts of Cu, Sn and As in steel are increased and the heating temperature is lowered, and the amount of the liquid to be eventually produced increases with the increase of scales. (3) The scalinig loss of samples necessary for non-ferrous liquid phase to be produced agrees exactly with the critical scaling loss for forming surface fissures mentioned in the 1st report, and the crack severity is proportional to the amount of the liquid. (4) The surface fissure is considered to be a kind of stress-corrosion crack brought about when external stress is applied to a steel sample with non-ferrous liquid phase existing on the surface. (5) The enriched phases, when not accompanying non-ferrous liquid, do not cause the usual fissures.
The directionality of hot-rolled Ni-Cr steel was investigated with a dilatometer and the following results were obtained: (1) By heating and cooling dimensional changes occurred and the changes depend on the rolling direction. (2) The same phenomena occurred by tempering. (3) Discussion of these phenomena were done with schematic figures. (4) By differential dilatometric method quantitative measurement of the directionality could be done. (5) By this method the elimination of directionality was studied.
Fully and partially pre-graphitized graphitic steels belonging to the Fe-C-Si system were subjected to some experiments on heat-treatment and the following results were obtained ; In fully pre-graphitized steel containing about 1.5%C and 1.5%Si, the period for resolution of graphite into austenite up to saturation at 850° is about 20 min, and in partially pre-graphitized same steel, it is about 10 min. The quenching hardness of this steel varies with the distribution of graphite perticles, that is, with the increase of the number of graphite particles the quenching hardness decreases. The hardenability of graphitic steel of this system increases with Si content, but decreases with C content.
Ultrathin tapes of 50%Fe-Ni alloy were rolled down to 0.006 mm in thickness. This study were restricted chiefly to the relation between the magnetic properties and degree of the reduction of the final cold rolling. (1) Then magnetic properties (Hc and Br⁄Bm) of the tapes more than 0.025 mm in thickness were improved with decrease of the thickness. (2) The magnetic properties (Hc and Br⁄Bm) of the tapes less than 0.0125 mm thick deteriorated with decrease of the thickness. (3) The factor causing the Hc and Br⁄Bm of the tapes less than 0.0125 mm thick to become inferior to those of the tapes more than 0.0125 mm thick is not the surface contamination of the tapes but their thickness itself.
From the analysis of the data obtained by creep tests of OFHC copper it is suggested that the initial part of the creep curve at high temperature corresponds to a rate process where the diffusion of super-saturated vacancies is the rate-determining process.Assuming that the extinction of one vacancy by diffusion contributes a unit amount of strain, which induces the climbing motion of a dislocation and the progress of the polygonization, and that the decrement of the vacancies is proportional to the number of the vacancies existing at that moment, it is shown that the proportional constant obeys the equation of the rate process, and that the activation energy of this constant is 23 kcal/mol, which is about the half value of the activation energy of self-diffusion of copper.
In the course of growing single crystals from nickel melt by the Bridgman method,it was found that the distance from the seed crystal to the starting point of a stray crystal, which was generally nucleated on the inner wall of the porcelain tube (alundum), depended on the lowering speed. Furthermore, the critical lowering speed necessary for producing single crystals of 10 cm in length decreased with the increase of the angle between the  direction and the specimen axis. The so-called cell structure was observed on the top free surface of the single crystal rods. This structure was divided by ditches into square or rectangular cells in the specimens grown in the directions of  and ,as in the case of Rosi’s observation on the copper single crystals. The line structure was observed on the side surface and the cell structure on the cross sectional surface by electrolytical etching method. A relation between the spacing of the line structure and the lowering speed was found in the case of the  direction.
Carbides electrolytically isolated from tungsten steels were studied by means of X-ray, thermomagnetic and chemical analysis, in order to elucidate the nature and occurrence of carbides, especially M23C6(κ-carbide), with respect to the chemical composition and heat-treatment of steel. The experimental data on the composition range of M23C6 show good agreement with those recently reported by K. Kuo. The Curie point of M23C6 varies from 150 to 400°, depending on its chemical composition and its thermal history. The contracted η-carbide (η*), observed by H. J. Goldschmidt in decarburizing of M6C, appeared in several low C- high W steels. The chemical formula of η* is considered to be M12C, which is formed by liberation of carbon from M6C.
The solid solubility ranges of the two intermetallic compounds,TiFe and TiFe2,in the titanium-iron binary system were studied by microscopic examination and X-ray analysis. The solid solubility range of the TiFe phase extends from 52 weight pct to 54 weight pct of iron and its solid solubility curves are nearly vertical against falling temperature,and the lattice parameter decreases with increase of iron concentration. The TiFe2 phase extends as widely as from 68.5 weight pct to 77 weight pct of iron at the temperature of about 1300°,and narrows down moderately with dropping temperature, and its lattice parameters c and a decrease with increase of the iron content while the axial ratio, c⁄a, remains approximately constant at 1.633.
The solid solubility ranges of the phases and their equilibrium relationships in the Ti-Fe-C system were studied by microscopic examinations and X-ray analysis. The results of investigation indicate that the following solid phases exist in this ternary system : titanium-rich solid solutions α or β, graphite, δ phase known as titanium carbide phase, TiFe phase, TiFe2 phase and iron-rich solid solution α or γ, but no ternary compound is detected. The δ phase region is given as from 13 to 20 weight%C and the maximum solid solubility of Fe in this phase is about 15 weight%. A change of the C concentration in the δ solid solution has a greater effect upon the lattice parameter of the δ phase than that of Fe concentration. The solid solubility of ternary TiFe phase is given as from 52 to 54 weight% of Fe and the maximum solubility of C is considered to be less than 0.1 weight%Fe. The ternary TiFe2 phase has a wide range of solubility of iron which extends from 69 weight pct to 77 weight pct of iron, and the maximum solid solubility of carbon in the TiFe2 phase is considered to be less than 0.2 weight pct of carbon. The δ solid solution is in equilibrium with α or β titanium, TiFe phase, TiFe2 phase, α or γ iron and graphite, and there exist two quasi-binary eutectic reactions of liquid\
ightleftarrowsδ+TiFe2 and liquid\
As the first step for studying the intergranular corrosion of alloys,the galvanic corrosion current of zinc,contacted with iron,a simple model of contact phases in alloys,was analysed graphically and represented as a function of the ratio of anodic and cathodic polarizations,the cathode area,the heat of activation of the cathode metal in hydrogen electrode reaction and the ion concentration of the cathode metal in solution.
The anodic polarization PA of β phases, electron compounds, and other intermetallic compounds AmBn increased suddenly and the corrosion potential of those compounds became noble at some values of Δx, the difference of electronegativities of A and B. This phenomenon was explained as originated in the change of the stability of B atom (base metal) in alloys and it was presumed that Tammann’s “Wirkungsgrenze” might be a similar phenomenon and be due rather to the change of some properties in the alloys, for instance, the ordered arrangement of atoms, than to an oxide film on the alloy surface.