MicroSim Bars® and PhasTranSim® are tools developed to assist R&D engineers in designing steel products with specific metallurgical and mechanical properties. MicroSim Bars® is a modeling tool that simulates the evolution of austenite during hot rolling of steel bars, considering factors like chemical composition, temperature, and deformation conditions. It predicts changes in the steel's microstructure during the rolling process, crucial for determining the final properties of the product. On the other hand, PhasTranSim® is a simulation tool that focuses on phase transformations in steels after hot rolling, considering the transformation from austenite to ferrite, pearlite, bainite or M/A constituents. It helps R&D engineers to understand how changes in process conditions impact the steel's microstructure and mechanical/metallurgical properties. These tools aid in efficiently developing steel products with desired characteristics while it is possible to reduce the costs. This paper will explain these tools, the validation for their development and will explore a real case where the alloy design was optimized with a possible cost reduction.