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Rolling wire rod
The rolling of coil is similar to bar, except that more rolling stands are used, so that the billet can be reduced down to smaller sizes. As the cross-section is reduced, the billet is extended, so that the final length of small coil sizes can be several kilometres. In order to handle this long length, the rolled stock passes through a helical tube, spinning at high speed, which forms the rod into a helical coil. One billet is rolled into a single finished coil.
The rings of the coil are controlled cooled, using fans to blow air over the product. This cooling can also be controlled to adjust the properties of the coil products. Coil produced in this way may be ribbed, for reinforcing steel applications, or plain for subsequent drawing to wire.