| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rolled magnet material without developing the barrel cracking of a bloom caused by heating and also, the cracking in hot-rolling by applying a tempering heated to a specific temp. after blooming or cogging a ingot and thereafter, applying hot-rolling. SOLUTION: The cast ingot of Fe-Cr-Co magnet material is bloom or cog in hot-state and as necessity requires, cut. This bloom is heated to 980-1030 deg.C. In this treatment, σ phase is fully eliminated and α single phase + network like γ phase, i.e., the structure precipitating the γ phase in the α phase is developed. After tempering, the hot-rolling is applied. By this method, the strength of the steel becomes high and the traverse crack (internal crack) in the hot- rolled bloom is not developed. Further, the surface temp. and the internal temp. of the bloom are comparatively uniformized by raising the temp. after keeping to a prescribed temp. for a prescribed time on the way of raising the temp. in the tempering, and the barrel crack on the bloom in not developed. |
