Abstract
A study on the punchability and weldability of electrical steel sheets with the insulting coating has brought to the following conclusions:
1) A new inorganic-organic insulting coating improves the punchability of electrical steel sheets by more than 30 times compared with the conventional inorganic insulating coating.
2) The reason for this marked improvement in punchability cannot be explained by the shearing energy involved.
Probably, the addition of organic matter decreases the side wear of the punch.
3) The weldability of electrical steel sheets with the new insulating coating is impaired by the gas evolved through the thermal decomposition of organic matter contained.
Release of this gas from around weld beads can enhance weldability.
An industrially advantageous method is to roughen the electrical steel sheet or the insulting coating itself.
In this way, a process has been established under which an inorganic-organic insulating coating is used as the surface coating of electrical steel sheets to satisfy their punchability and weldability requirements at the same time.
