Differential cooling is successfully used in automobile industry to obtain tailored mechanical properties along the thin-walled beams using tool or spray quenching. Thicker steel plates used for soil-working tools in agriculture require high hardness, and therefore, are hardened in water. However, differential cooling of such tools can improve their durability by creating hardness gradients suitable for the spatial variation of loadings that they are subject to. Therefore, the focus of this study is, using Impinging jet Quenching Technique (IJQT), to perform differential cooling of 15 mm steel plate with different water and air flow rates, thus generating a temporal and spatial temperature evolution data. This data is used for further simulations of phase transformations and final hardness gradient predictions in application to other steels using their chemical composition as an input parameter. The experiments resulted in a wide range of cooling rates of 1–43°Cs−1 along the steel plate, generated by different cooling strategies. The simulations showed different combinations of hardness levels along the sample of three simulated steels with different hardenability levels, demonstrating the potential of implementing the same approach for further studies of other steels in terms of their capability of providing necessary hardness gradients using IJQT.