A method for thermal-diffusion chromizing in powders is proposed, which includes preliminary electrolytic hydrogenation under cathodic polarization in a 26%-sulfuric-acid solution. The results presented in the work convincingly demonstrate the effectiveness of hydrogenation for increasing the thickness of the carbide zone of critical steels and cast irons. Preliminary hydrogenation increases significantly the thickness of the carbide zone of the diffusion layer. Analysis of the obtained dependences shows that the most intense growth of the carbide layer occurs at the current density of anodic polarization: for carbonaceous cores, i = 1−3 mA/mm², and for cast iron, i = 0.5−2.0 mA/mm². Thus, the thickness of the carbide zone on carbonaceous steel 20 and 45 are increased by approximately 3 times, and on cast iron, by 1.4 times. Furthermore, optimization is conducted to find the optimal conditions for hydrogenation to achieve the maximum thickness of the carbide zone of the chromized layer, which determines the cavitation–erosion resistance of steels in technological solutions of food productions, particularly, in solutions of table salt. In this case, the cavitation–erosion resistance (based on weight loss over 3 hours of testing on a magnetostriction vibrator) in a 3%-NaCl solution is increased for steel 45 by 10 times, for steel 20, by 12 times compared to normalized ones, for cast iron SCh20, by 3.6 times compared to standard chromizing, and by 25 times compared to its resistance in the delivered state.