The boom is one of the key parts of the excavator frame (boss). In the early stage, this product was produced by welding forgings and round steel. However, during the use of excavator, the boss of large root arm carries alternating load in all directions, so there is a great risk of cracking at the welding joint. Compared with forging, welding and other production methods, casting has the advantages of low production cost and low cracking risk. Therefore, the product process is adjusted to cast steel as a whole. In order to shorten the development and trial production cycle, the enterprise used ProCAST software to numerically analyze the casting molding process, and predicted the shrinkage cavity, shrinkage porosity position and hot crack tendency of the casting.
(1) The casting process of the connecting boss of the large root arm of the excavator was numerically simulated by ProCAST simulation software. Through the data analysis of the mold filling process and solidification process, the possibility of insufficient filling of the casting and the distribution of shrinkage cavity and porosity defects were effectively predicted.
(2) After comparing the HTI data of the three process schemes, the process scheme of using limestone sand instead of silica sand to make core without cold iron is finally selected. It not only reduces the difficulty of sand mold making, but also reduces the risk of hot crack defects in the thickness transition part of the casting. Through production verification, the castings meet the production quality requirements.
(3) It shortens the development cycle of numerical simulation software and reduces the cost of product design.
The practice shows that the close combination of computer simulation technology and casting process design achieves the purpose of optimizing process design and improving the economic benefit and competitiveness of products.