Evanescent mode vacant-shell casting technique of double-saddle balance shaft shell

Abstract

The invention relates to an evanescent mode vacant-shell casting technique of a double-saddle balance shaft shell. The evanescent mode vacant-shell casting technique comprises the following steps: (1) producing a double-saddle balance shaft shell and a riser foam mold by foaming copolymerization (STMMA), independently producing a pouring gate, bonding a double-saddle balance shaft shell module and the pouring riser to form a combined model; (2) roasting the combined model in a roasting room at the temperature of 50 to 60 DEG C for 24h; (3) placing the roasted combined model into a high-temperature-resisting and high-strength paint pool to be painted, then roasting the combined model in the roasting room, painting and roasting the combined model for four times, and controlling the thickness at 1.2mm to 1.8mm; (4) combining the roasted combined models again on an iron rack in a way that four combined models form on pouring body, and roasting the combined model; (5) boxing, filling sand and compacting; (6) vacuumizing a sand box, and burning the model in rich oxygen to form a vacant shell; and (7) casting.

Description

Technical field: [0001] The invention belongs to the field of casting technology, and in particular relates to a lost-foam hollow shell casting technology for a double-rider balance shaft shell. Background technique [0002] The double-riding balance shaft housing is a complex casting, which is usually manufactured by ordinary sand casting, which is difficult and has a high scrap rate. However, in the general lost foam manufacturing, the castings are seriously carbonized and have many defects. The Chinese patent with the authorized notification number CN102328025B discloses a lost foam casting method for the balance shaft housing, which includes the following steps: A1, using polystyrene foamed plastic to make the overall lost foam model, and the pouring riser is made separately The pouring riser is a hollow cylindrical type, and the model and the pouring riser are combined and bonded together to obtain a combined model for casting; A2, the combined model is put into the co...

AI Technical Summary

Problems solved by technology

[0003] Although this casting method has improved the surface quality of castings to a certain extent, it has been found in practical applications that the effect of using polystyrene foamed plastics for overall foaming to make the overall model of lost foam is still unsatisfactory. After the foam plastic is foamed, it is easy to produce pores and carbon increase during the pouring process, which will affect the quality of the casting. At the same time, although the combined model has been baked for 3 times, the shape of the model is still not firm enough, and the fire resistance of the refractory aggregate is stable. There are also deficiencies in the casting method, which is prone to sand inclusion defects, and the combined model is still prone to deformation due to pressure changes after vacuuming. Therefore, there are still many areas for improvement in this casting method.

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