The current Cold Upsetting Steel wire rod continent can provide 5.5?~40?, the more mature range is 6.5?~25? High-grade fasteners on the quality of raw materials requirements are as follows: the coil has a high plastic index, high sectional shrinkage and elongation; in the cold plastic deformation, the material deformation resistance is small, low processing hardening rate, the material yield strength ratio is small and the coil hardness HRB appropriate, not too high; the coil has a good surface quality, should be smooth and round, no bump folding, scarring cracks, pockmarks, etc., the steel organization is dense, no Internal defects
