Akira Sakakura

New grain-oriented silicon steel with high permeability "ORIENTCORE HI-B"

A new grain-oriented silicon steel with a higher degree of grain orientation than usually obtainable by known conventional procedures was developed. The new material (HI-B) has made large improvements in core loss and magnetostriction characteristics by effects due to surface coating that are more remarkable with a higher degree of grain orientation. HI-B is 2-3 grade better than todays conventional products. Furthermore, there will be the possibility of improvement by 1-2 grade in the near future. HI-B has lower linear magnetostriction as compared to conventional material and is less sensitive to stress in spite of superior magnetic properties. Actual transformers made from HI-B materials have improved transformer characteristics such as core loss, exciting VA, and noise, reflecting the magnetic properties of materials.

Characteristics of Magnetic Properties of Grain‐Oriented Silicon Iron with High Permeability

Grain‐oriented silicon iron with high permeability is prepared using aluminum‐nitride needles to restrain normal grain growth. The improvements in hysteresis loss of specimens with a permeability of 1920 are about 0.120 W/kg at 15 kG and 0.160 W/kg at 17 kG as compared to the commerical product with a permeability of 1820. That is the reason why the crystal orientation has a strong influence on total loss, especially at B = 17 kG. The effect of grain size on total loss is important also. The detrimental aluminum nitride and aluminum oxide are not present in the base metal after final annealing. For example, aluminum oxide is removed from the base metal and absorbed into a glass film. Glass‐type coating plays a dominant role, not only for the magnetostriction, but also for total loss of these specimens with high permeability, especially in thin‐gauge specimens.

Effects of AlN on the Primary Recrystallization Textures in Cold‐Rolled‐(110)[001]‐Oriented Single Crystals of 3% Silicon Iron

Cold‐rolled‐(110)[001]‐oriented single crystals of 3% silicon iron containing AlN in solution develop a doublet {111} 〈110〉−oriented primary recrystallization texture consisting of grains with diameter of 0.5 to 1 mm after anneal at 550°C for 40 h followed by anneal at 1200°C. At the first anneal, very fine needle‐like AlN precipitates, while (110)[001]‐oriented primaries begin to originate at the surface of the sheet. At the heating process of the subsequent anneal, doublet {111} 〈110〉−oriented primaries originate at the middle of the sheet, and then grow at the expense of (110)[001]‐oriented primaries. It is proved that very fine needle‐like AlN precipitated after cold rolling is found to have a great effect on these primary recrystallization phenomena.

The effects of AIN on secondary recrystallization textures in cross rolled and annealed (001) (hkl) oriented single crystals of 3 Pct Si-Fe

A study was made of the effects of A1N on the recrystallization textures in cross rolled and annealed (001)[hkl] oriented single crystals of 3 pct Si-Fe and A1N was found to have a great effect on secondary recrystallization textures. Cross rolled and annealed (001)[hkl] oriented crystals containing fine needle-like A1N about 1 µ or less in length develop (001)[hkl] oriented secondary recrystallization textures at the expense of the primary recrystallized matrix. Furthermore, very fine needles of A1N contained in (001)[110] oriented single crystals control the orientation of primary recrystallization textures.

Effects of AlN on the secondary recrystallization behavior of 3% Si‐Fe (110) [001] single crystals

Cold rolled (110) [001] single crystals of 3% Si‐Fe containing AlN controlled adequately in size, distribution and quantity develop the original (110) [001] or cube‐on‐edge orientation by seconary recrystallization after an anneal at 550°C for 40h followed by an anneal at 1200°C. During the course of secondary recrystallization, (110) [001] primaries grow at the expense of {111} 〈110〉 and {120} 〈001〉 main primaries.