Operation of pipe-rolling mills has been considered. Problem of determining the rational passes has been discussed. Procedures of pass calculation, developed by NITI-NTZ, MISiS, UralNITI Institutes have been described. Comparison of the procedures has been made. Improvement in deformation conditions has been considered. Determination of true reductions has been discussed. Opportunity for prevention of variations in wall thickness has been described. Accuracy of setting the function of true reductions has been evaluated. Requirements to pipe accuracy have been taken into account. Shaped mandrel application during ShKh15 steel rolling has been described.