15 coil nails

In the rolling process, if the surface of the steel wire is rough, the relative friction coefficient of the steel wire and roll increases, the friction resistance increases, the steel wire elongation decreases, the width increases. In the production of weighted leather material is easy to wide, is because of its rough surface. On the contrary, the surface of the steel wire is smooth, because the friction resistance between the steel wire and the roll is small, it is easy to extend, and the width is small. Domestic steel wire in order to prevent rust, the surface coated with butter, such as butter removal is not clean, easy to slip when rolled flat, also affect its width.