42CrMo steel bars are widely used in machinery manufacturing for producing high-load core components such as heavy-duty gear blanks, crankshafts, connecting rods, and hydraulic cylinder rods, as their excellent tensile strength, impact toughness, and hardenability ensure stable operation under high pressure and frequent stress. In the automotive and engineering machinery fields, they are applied to make transmission shafts, chassis load-bearing rods, and excavator boom pivot shafts, benefiting from strong fatigue resistance that extends component service life. They also find use in the energy sector (for high-pressure pipeline flanges and turbine rotor shafts) and the mold industry (for medium-sized mold guide pillars and ejector pins), serving as a critical material for industrial scenarios requiring both high strength and durability.