On the surface of the wire and the body of the adhesion of a head or completely non-adhesive metal layer called scarring. Generally it is tongue-shaped, uneven thickness and size. Some scars are rooted, some not rooted, in the full length of the wire, regular or irregular distribution.
Scars will impact on the wire surface quality grade, in deep processing, easy to burr, and in severe cases are also prone to fracture, influence the drawing performance.
The cause of scarring
1. Raw materials themselves exist lug, folding or scarring (with the coil body part of the combination);
2. Rolling surface iron oxide is not clean, pressed into the rolling surface to form scars;
3. The folded layer is pulled apart into scars after further rolling;
4. There is debris on the surface of the rolled parts, while being brought into the rolling groove, after rolling, is attached to the surface of the rolled parts. This kind of scarring is not rooted and irregular distribution.
5. There are serious scratches on the rolled parts during the rolling process;
6. Iron chips are adhered to the surface of the guide;
7. Non-finished hole rolling groove with a large pit, pressed into a bump during rolling, and then rolled to form periodic scarring.
Prevention methods
1 Prevent the surface of the billet with quality defects into the next process;
2.Reasonable control of the heating process, to avoid the billet surface oxide layer is too thick;
3 Check the inner surface of the guide carefully, and remove the parts with iron oxide in time;
4.Reasonably adjust the second flow among stands to avoid scratching the rolled parts;
5.Strengthen the inspection of the surface quality of the rolling groove.
