Effect Of Surface Quality On Damage Of Oriented Silicon Steel

Effect of surface quality on damage of oriented silicon steel

The surface quality of oriented silicon steel (including bottom mass, inner oxidation layer and surface oxidation) has obvious influence on iron loss, but the degree and mechanism of influence of each factor on iron loss are still unclear. The effects of surface quality factors on iron loss were studied by comparing the changes of iron loss before and after pickling after removing the outer oxide layer, the changes of iron loss after pickling after removing the bottom layer, and the changes of iron loss after polishing after removing the bottom layer and the inner oxide layer. It is found that surface oxidation has no obvious effect on iron loss, and inner oxidation layer has the greatest effect on iron loss. The morphology and composition of the inner oxide layer were analyzed by scanning electron microscopy. It was found that the inner oxide layer was a discrete particle of magnesia olivine and spinel. The inner oxide layer increases the iron loss by its pinning of the 180 wall movement and the bottom layer increases the iron loss by increasing the volume fraction of the 90 closed domains.

Oriented silicon steel is a kind of metal functional material widely used in transformer core. Due to the iron loss of oriented silicon steel, the power transformer will lose a lot of electric energy. There is a layer of magnesium silicate on the surface of oriented silicon steel, which is formed by the reaction of SiO2 formed in the process of decarburization annealing and MgO coated before high temperature annealing. The presence of magnesium silicate substrate can avoid the bonding of steel strip during high temperature annealing and improve the adhesion of the surface insulating coating. The surface quality of oriented silicon steel includes the bottom mass, the inner oxidation layer and the surface oxidation during high temperature annealing and cooling.