Machining method for eccentric crankshaft of hay mower

The invention relates to a machining method for an eccentric crankshaft of a hay mower. The machining method comprises the following steps that a, a raw material steel bar is cut into a plurality of steel sections, the steel sections are heated and softened under the condition of the temperature ranging from 1,185 DEG C to 1,215 DEG C, then the steel sections are placed in a die to be subjected to heading preforming, and then an air hammer is adopted for being matched with a clamp for forging the steel sections into the shape similar to the crankshaft; b, the steel sections treated in the step a are placed in a forming die, the eccentric crankshaft with the machining allowance left is formed through forging and pressing, and trimmings are removed; and c, the eccentric crankshaft is immersed in water to be cooled, and then an oxide skin on the surface of the eccentric crankshaft is removed. Accordingly, on one hand, the oxide skin can be formed on the surface of the eccentric crankshaft; and on the other hand, the metallographical reaction can be conducted in the steel sections, and finally the strength and tenacity of the eccentric crankshaft can be improved.