Timken 16-25-6 耐熱鋼に及ぼす N の影響並にその電子顯微鏡的考察 : 耐熱鋼の研究 IX

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(1) studies were made on the hardness, the optical microscopic structure, the micro-hardness and the electron-microscopic structure of the 8 samples, Cr 16-Ni 25 and Cr 16-Ni 25-Mo 6% series, each N not added and about 0.08, 0.12, 0.22% N added respectively, and of the other 8 samples, Cr 16-Ni 25, Cr 16-Ni 25-Mo 6, Cr 25-Ni 25-Mo 6 and Cr 35-Ni 25-Mo 6% series, each N not added and about 0.2% N added respectively, after solution-treated at 1000-1200℃, then aged at the temperatures up to about 900℃. By these results author studied the iufluences of N and, at the same time, of Cr and Mo. (2) When the N content is higher, the hardness becomes generally also higher or has little difference, after variously heat-treated. Then author explained the changes of hardness due to the durations and the temperatures of ageing, and the influences of the solutiontreating temperatures upon these changes, according to the coagulation of the precipitated particles and the assumption of the solubility limit curves of C & N into γ. (3) Next author observed their optical microscopic-structures. The samples, containiog N more over about 0.12%, have the banded structures of the colonies of the nitride particles, when quenched at about 1000℃. If N% becomes higher, there appear more colonies and the particles become more bigger. At about 1200℃ these colonies dissolve in γ completely. But when tempered at about 800℃, if N% becomes higher, the precipitates at the grain-boundaries and the cleavages become more abundant, and, at the same time, there appear more the Neumann line-like fine parallel-line structures at all over the ground-masses in every grains. When Mo is added, these appear similarly. (4) By the microhardness tests, the maximum hardness differences between the grains of this steel amount to about 100, beyond our expection. The hardness differences between the interiors and the boundaries of the grains, and those between the positions where the colonies of particles sit or not, are generally 20-50. On the 35-25-6 series, we could assume the α+δ and γ phase by this micro-hardness test. (5) studies were made on the electron-microscopic structures of these samples, checking the relation between the optical microscopic-structures and the electron-microscopic images. Comparing the micro-photographs of the 1st images pressed on the surfaces of the treated methyl-methacrylate monomer with the optical microscopic structure photographs, we could confirm that the fine particles of the colonies of the N-rich samples and their fine parallel-line structures due to the precipitation in the grains, etc. were pressed correctly and minutely. By the micro-photographs of the 2nd images pressed on the surfaces of their replicas, Al films (250A) spreaded on the Cu-screens and capped, the films have the wrinkles very much, especially at the meshes of Cu-screens the films slack loose surprisingly, but it was confirmed that this did not prevent to observe the electron-microstructures at the high magnifications. These studies on checking were seen in no reference in Japan. By many electron-microphotographs of these samples, there are much differences between the degrees of the roughness of the surfaces of the grains, and the grain boundaries and the cleavages have many cases of the appearances electron-microscopically. Besides these results, it was found that, on the samples ccntaining much N and Mo, quenched from about 1200℃ and tempered at about 800℃, among the fine parallel-line structures, the continuation of the bands or the particles. about 5, 000A. which we can observe by the opticalmicroscope, there are the ultra finer parallel-lines, the continuation of the particles, about 500-1400A. The high high-temperature creep resistances of the Timken 16-25-6 heat-resisting steels by addition of Mo and N owe to these structures of the lines, the continuations of the ultra-fine electron-microscopic particles.
社団法人日本鉄鋼協会の論文
1952-11-25

著者

出口喜勇爾
日本特殊鋼

Timken 16-25-6 耐熱鋼に及ぼす N の影響並にその電子顯微鏡的考察 : 耐熱鋼の研究 IX

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