1 Production Process
The production process is shown in Fig. 1 ~ 5, including coating spraying, coating drying, core setting, box closing pouring and sand falling out of box.
2 Casting Inspection
2.1 Surface Quality Comparison
Compared with resin sand process, the surface quality of castings produced by V-process is obviously improved. The comparison of surface quality is shown in Fig. 6 and Fig. 7.
2.2 Internal Quality Inspection
The thick part of the casting blank was cut by wire cutting, and the internal structure was observed to be compact without casting defects such as porosity, shrinkage porosity, slag inclusion and shrinkage cavity, as shown in Figure 8.
2.3 Mechanical Property Test
Due to the particularity of the vacuum casting process, the surface of the casting tends to cool rapidly at the end of the casting. The main reason is that the sand is dry and cold, and the liquid metal is quenched in a short time, but after the sand is heated, the cooling rate will slow down, and the number of eutectic clusters is less, and the pearlite content in the matrix is lower, The mechanical properties and impact toughness of the material can not meet the technical requirements.
Through analysis and research, the method of adding 0.3% copper, controlling the final silicon at about 2.4% and sand falling out of the box 5 ~ 6 h after pouring is found out. The mechanical properties of the castings produced can meet the technical requirements of customers. The wall thickness of the attached test block is 60 ~ 200 mm.
2.4 Casting Processing
After machining, the casting blank of the forklift front axle meets the technical requirements of the drawing. The processed products are shown in Figure 9.
