hi there.i had always wondered why the dull blue/grey metal flat bars i buy would not be in a poor state of corrosion as they are not painted.only the ends are a bit rusty. they are not of the galvanized type.
i used to think that they were sprayed lightly with oil to stop corrosion. recently i was bending one to get a required curve and i noticed a coating flaking off the bar in the bend. sheet/angle & box section also come coated this way.
any idea what this coating is?some sort of thin electroplated paint? do you people sand it off before welding?
Sam