As one of the key parts of the engine, the crankshaft bears the combined action of alternating bending and alternating torsional loads during the movement. In particular, the transition fillet between the journal and the crank bears the greatest alternating stress, and the crankshaft fillet position often causes the crankshaft to break due to high stress concentration. Therefore, in the crankshaft design and manufacturing process, it is necessary to strengthen the crankshaft fillet position to improve the overall performance of the crankshaft. Crankshaft fillet strengthening usually adopts induction hardening, nitriding treatment, fillet shot peening, fillet rolling and laser shock.

Shot blasting is used to remove oxide scale, rust, sand and old paint film on medium and large metal products and castings that have a thickness of not less than 2mm or do not require accurate dimensions and contours. It is a cleaning method before surface coating. Shot peening is also called shot peening, which is one of the effective methods to reduce fatigue of parts and increase life span.

Shot peening is divided into shot peening and sand blasting. Using shot blasting for surface treatment, the impact force is large, and the cleaning effect is obvious. However, the treatment of thin plate workpieces by shot peening can easily deform the workpiece, and the steel shot hits the surface of the workpiece (whether shot blasting or shot peening) to deform the metal substrate. Because Fe3O4 and Fe2O3 have no plasticity, they peel off after being broken, and the oil film is The base material deforms at the same time, so the shot blasting and shot blasting cannot completely remove the oil stains on the work piece with oil stains. Among the existing surface treatment methods for workpieces, the best cleaning effect is sandblasting.