In the drawing process of steel wire, the iron oxide (scale) on the wire surface must be removed thoroughly to have good surface finish of the wire product, that can reduce the loss of drawing die loss. The scaling of metal wire is done by chemical, mechanical and photoelectric methods.
Chemical pickling can be divided into circular pickling, linear pickling, vibratory pickling, electrolytic pickling, ultrasonic pickling, spiral pickling, continuous pickling, closed pickling, etc. The pickling technology is easy to operate, and the waste acid should be recycled and reused.
Mechanical methods include shot blasting and scale removal, bending roller scale removal, sand belt scale removal, high-pressure water (gas) sandblasting scale removal, mechanical processing method skin removal and wire brush scale removal etc.
Shot blasting (sand) descaling includes off-line type whole-roll descaling and on-line type single-root descaling. The whole volume descaling has large investment and high efficiency. Online type descaling has low investment and better descaling effect. Shot (sand) descaling operation is not effective in removing iron oxide with good extension performance, and it will form a hardened layer on the wire surface, which is not conducive to subsequent drawing.
Bending roller descaling is to take advantage of the low elongation and brittleness of iron oxide, and bend the wire repeatedly by pressing the twisted wheel, so as to achieve the purpose of scale breaking and descaling, and then combined with the subsequent sanding belt or wire brush to remove the residual and broken iron oxide. This combination of scale-removal method is good for carbon steel, but if the elongation of iron oxide is greater than 10%, the removal effect is not good.
The belt descaling technique consists of two sets of front and rear tensioned abrasive belts which are used to remove the scale from the wire by the combined motion of rotation and rotation. The sanding belt can be selected according to the material of the wire, and the thickness of the sanding belt can also be selected according to the surface condition. If the surface roundness of the wire is good, the iron oxide on the surface of the wire can be completely removed, if the wire has defects, the effect of descaling of this wire is not obvious.
