Mineo Muraki

Control of recrystallization during high-temperature hot-rolling of grain-oriented silicon steel

Recrystallization kinetics of 3 % Si steel after hot rolling in the temperatures between 1373 and 1573 K, which is quite important to obtain uniform magnetic properties, was studied. Recrystallization rate after hot rolling was relatively slow because of low dislocation density, which resulted from rapid recovery, and its behavior was strongly influenced by the initial grain size and coexistence of the γphase. Based on these Findings, controlling technology of recrystallization during hot rolling of grain-oriented Si steels is discussed.

Development of high-temperature hot-rolling process for grain-oriented silicon steel

A numerical study was conducted to analyze the dissolution process of manganese sulfide, and the advantages of very-high-temperature and short-time slab reheating prior to hot rolling were demonstrated. Inhibitor dissolution was greatly accelerated at elevated temperatures. High-temperature and short-time slab reheating also facilitated structure refinement by static recrystallization with appropriate rolling schedules and reduced initial grain sizes. This recrystallization also served to improve product surface quality. Another advantage of the high-temperature hot-rolling process is increased flexibility for controlling inhibitor precipitation during hot rolling.

Cold-Rolled Micro-Texture in Polycrystalline 3%Si-Fe

Cold-rolled micro-texture of polycrystalline 3%Si-Fe was investigated using high-resolution Electron BackScattering Patterns (EBSP) method. There were deformation bands near grain boundaries. The orientation relationship between the deformation bands and the surrounding deformed grains is explained by the orientation rotation around a <211> axis. The activated slip to generate these deformation bands is estimated from the <211> rotation. The S-value, which is a geometrical index of slip operation against applied stress, of this slip system was not maximum value of all, but it had a common slip plane with an adjacent grain. A hypothesis that the slip system having a common slip plane with an adjacent grain is activated was proposed from the present results.