Free forging process for large forgings

Large forgings usually refer to the forging of steel ingots weighing over 10 tons into various heavy-duty machinery forgings using a hydraulic press with a load of over 

1000 kN or a forging hammer with a load of over 50 kN. Such as impellers, rotors, retaining rings, high-pressure vessels, large crankshafts, and rolling mill rolls for power 

plant equipment. This type of forging is a key component of heavy-duty machinery, requiring high mechanical performance and reliable quality. But the production batch 

is generally not large, and the appearance is not too complex. Therefore, in the production process of large forgings, ensuring the quality of forgings is often the primary 

issue in formulating processes.

Steel ingots are used as billets for large forgings. The larger the weight and size of the steel ingot, the more severe the defects in the internal organizational structure. 

To ensure the quality of forgings, the forging process should try to fully eliminate these defects during the processing, and then forge them into forgings that meet the 

requirements of shape, size, and performance. So the forging and pressing processing of large forgings has a dual function of billet forging and forming forging.

The equipment for free forging is divided into two categories: forging hammers and hydraulic presses. The forging hammers used in production include air hammers and steam air hammers. Some factories also use spring hammers, clamp hammers, lever hammers, and wire hammers with simple structures and low investment. Hydraulic press is the only way to produce large forgings by using static pressure generated by liquids to deform the billet.

The basic processes of free forging include upsetting, elongation, punching, bending, twisting, displacement, cutting, and forging.