Abstract:There are warping in 4 consecutive batches of 1215MS free cutting steel wire rode .Firstly , the result of investigation on the quality of the other batches of wire rode made from the same cast number billets which the 4 batches belong to excludes the possibility of the whole cast billets with quality problem. Secondly , factors warping concern eg. composition, rimhole, smelt and rolling process are investigated. From which rolling temperature, billets surface quality, inclusion has become the focus of the suspected factors. Thirdly , the main factor is determined by production and research, and confirmed by production finally. The results show that 1215MS free cutting steel wire rode warping is caused by rolling temperature and purity of steel,there is no evident relation between warping and billet surface defects as bin-hole,oscillation mark. Higher rolling temperature can avoid the wire rode warping defect occur.