Abstract:A throughout investigation has been carried out on the flatness measurement system and flatness control system of the Ansteel 1450 tandem cold mill. Temperature difference across the strip width which the flatness control system has not taken account into can corrupt the flatness measurement. Bad flatness will come into being when there has a large temperature difference distribution over the strip width due to a large reduction. For purpose of avoiding this, a compensation for temperature grads is applied to the flatness target curve. The results indicated that the compensated flatness is excellent and the strip with better flatness can be obtained after the compensation.