Hot Band Grain Research Articles

Influence of composition and hot rolling parameters on the magnetic and mechanical properties of fully processed non-oriented low-Si electrical steels

The influence of composition (Si, Al, Mn. P and B) and hot rolling parameters on the properties of fully processed ultra-low carbon. low Si, non oriented electrical steels was investigated. Nine steels were examined, using twelve combinations of slab reheating temperature, finishing temperature and coiling temperature. It was found that maximisation of the polarisation through composition generally causes an increase in core losses. Hot band and final grain size influence the magnetic and mechanical properties more than composition. The grain boundary segregation of P results in finer grains and lower polarisations. Increasing the Mn and/or Al content coarsens the final grains as a result of coarser MnS.and/or AIN precipitates.

Effect of hot rolling parameters on the magnetic properties of a low-silicon ultra-low-carbon steel

An ultra-low-carbon steel was hot rolled with various reheating, finishing and coiling temperatures. A significant reduction of the core losses after cold rolling and annealing can be obtained by lowering the slab reheating temperature, which results in a coarser precipitate structure and final grain. The magnetic induction can be increased by realising a coarse hot band grain structure.

Effect of hot-band grain size on magnetic properties of non-oriented electrical steels

Hot-band grain size of 0.5% Si steels was changed from 42 to 115 μm by various combinations of several hot rolling and annealing conditions. The hot-bands were cold rolled from 2.3 to 0.50 mm and finally annealed for 1 min at several temperatures between 750 °C and 950°C. The values of magnetic induction B50 in the directions of 0° and 90° from the rolling direction increase, whereas that of 45° direction decreases a little with an increase in the hot-band grain size. The core loss W15/50 in 0°, 45° and 90° directions decreases altogether with an increase in the hot-band grain size. The change in B50 with an increase in the hot-band grain size is caused by decreases of (110) component in the annealing texture. The change in W15/50 with an increase in the hot-band grain size is accounted for both of the grain size and texture effects.