Forging process of engine crankshaft

The invention discloses a forging process of an engine crankshaft. The forging process includes the following steps: 1), for first fire, holding a bar by a pressing clamp, biting the bottom, upsetting and drawing; 2), for second fire, upsetting, drawing and performing number printing, wherein number printing depth is 120; 3), for third fire, using a 120-degree up-down V-shaped anvil to perform turn grinding, finishing and straightening, wherein grinding shift amount is 170; 4), pressing a turn (2), using an angle square to determine an angle, pressing a turn (3), and pressing a turn (1); 5), performing number printing, pressing out a bottom end small shaft (5), and pressing out a small shaft (4) between a flange and the turn (1); 6), rounding the flange to be in a process size, using the angle square to check relative angle of all turns after reaching the required size, using a wrench to adjust the relative angle of the turns by taking a middle turn as a reference, chamfering sides of each turn, finishing, straightening and completing. Metal fibers of a forged crankshaft are continuous and free of distortion, the forged crankshaft is high in quality, long in service life, few in tool aid input, high in additional value and obvious in economic benefit, and the forging process is applicable to forging production of various crankshafts.