鐵鋼の再結晶軟化に及ぼす合金元素の影響

抄録

The present report supplys some data on the recrystallization softening of cold-rolled alloyed iron and steels, with'a point of view to survey the effect of the alloying elements on the rigidity of steel at high temperature.
The samples were prepared by induction melting in magnesia-lining crucibles, using 0.08% C Swedish steel and the best grade of metals or ferro-alloys as the alloying materials. After complete annealing, these alloyed iron bars were subjected to cold rolling of 20% and 50% reduction in thickness. And Brinell hardness tests were carried out upon the sections of these rolled bars, which were reannealed at various temperatures (300 to 1000°C) for a constant period of time (2hr), and also at a constant temperature (550, 600, 650 or 700°C) for vafious periods of time (2min to 100hr).
The results obtained were shown in Figs. 1, 2, 4 and 5, from which the following conclusions were drawn.
(1) Nb, Ti, Mo, W, V, Cr and Co raised the recrystallization temperature, and retarded the softening of steel accompanied by annealing.
(2) Ni, Mn, Si, Al, Sn and P hardly changed the range of softening temperature of ferritic steel.
(3) Cu, added more than the solubility limit for iron, raised the softening temperature of steel.
(4) Cold rolled 0.65%C steel having spheroidal structure was easily softened than the lamellar one by annealing.
(5) High Ni-or high Mn-steel having austenitic structures showed higher softening temperatures than the ferritic ones.