Wet sand casting process of Nodular Iron Crankshaft

Crankshaft is one of the most important components of automobile engine. For automobile crankshaft, its main function is to realize the power output of engine. On the one hand, it bears the influence of fatigue factors such as torsion and bending, on the other hand, it also needs to bear the impact of crankshaft connecting rod. According to the inspection data of crankshaft damage [1], the impact of crankshaft wear, torsion, bending, etc. on the crankshaft accounts for the majority. Therefore, for the casting process of crankshaft, when the crankshaft material is reasonably selected, the casting process should also be analyzed to reduce the casting defects of crankshaft and effectively control the quality of castings in the casting process, so as to ensure the qualified rate of castings, Improve the efficiency of casting production.

Because of the particularity of crankshaft, not only the material has good mechanical properties, but also the material economy of crankshaft. Nodular cast iron is a kind of alloy material with good mechanical properties and economic rationality. Compared with other cast steel materials, nodular cast iron has not only good anti torsion and bending properties, but also shows great advantages in the face of the impact transmitted by the crankshaft connecting rod. In this paper, qt900-2 is used for automobile crankshaft to improve the structure of nodular cast iron by adding different elements, Meet the needs of automobile crankshaft application.

The wet sand casting process of nodular iron crankshaft is mainly divided into two parts: sand mold preparation and pouring. For the sand ratio required by the crankshaft wet sand mold, the new sand with a mass fraction of 5% and the residual sand with a reasonable proportion can be used as the composition of used sand. The wet sand casting process of nodular iron crankshaft adopts the sequential solidification process scheme, as shown in Figure 1, which is not only suitable for large-scale production of crankshaft, In addition, the defects of the casting can be reasonably controlled by controlling the relevant processes in the process link, so as to improve the qualification rate of the casting crankshaft.

The production practice shows that the ductile iron crankshaft by wet sand casting greatly simplifies the production process of the common crankshaft, meets the mechanical properties of the engine crankshaft, and reduces the production cost of the crankshaft. At the same time, for the control of casting defects, the casting defects in the process of wet sand casting are also easy to overcome or even eliminate in the process, thus ensuring the quality of the crankshaft.

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