The permanent improving of physical and mechanical properties of cast alloys, the improving of old processes and the introduction of new processes allowing to get a precision casting with a soft surface and not demanding the machining and, finally, a constant increasing of the productivity of applied processes change not just technological but economic case of the modern foundry. The computer modeling becomes an inalienable part of processes of the new model design and the engineering of technological processes for its production. It gets a status of an important and often a decisive competitive advantage. The computing of the gating system for casting of 20x5ML steel was completed and the most optimal option allowing getting castings without defects was found with LVMflow modeling program. Output of valid casting was computed, there were finding out a needed metal filling of furnace and selecting batch's material to get the necessary chemical compound of alloy. Based on condition that the smelting will be carried out on return and fresh materials, a spending of acquisition has been defined. Then the way of computing was used as an initial variant to the checking modeling with ProCAST program which allowed to obtain higher amount of valid castings due to the changing the design of gate system. It let change metal filling of furnace and pick up a need in fresh materials in the different way. The calculation of costs for acquisition is revealed that the using of ProCAST let to achieve the reducing to get casting with saving needed quality of alloy.