Crankshaft — a part of complex shape, having a neck for connecting rods, which takes the effort and converts them into torque.Crankshafts are made of carbon, chromium-manganese, chromium-Nickel-molybdenum, and other steels, as well as special high-strength cast irons. The advantage of steel shafts is the highest strength, the possibility of obtaining high hardness of the necks by nitriding, cast iron shafts – cheaper.

Billets of steel crankshafts of the average sizes in large-scale and mass production make forging in the closed stamps on hammers or presses, thus process of preparation of preparation passes some operations.

Due to the high requirements of the mechanical strength of the shaft is of great importance the location of the material fibers in the preparation of the workpiece to avoid cutting them in the subsequent machining. To do this, use stamps with a special bending streams. After stamping before machining, the billet shafts are subjected to heat treatment.