Lost-foam casting process

Abstract

The invention relates to a lost-foam casting process which overcomes the technical bias existing in the prior art of mould shell collapsing due to the uncovered plastic cloth after finishing casting and is successfully developed. The process comprises the following steps: after the casing step of the traditional lost-foam casting process is finished, the plastic cloth is immediately uncovered, the vacuum is continued to be extracted for a plurality of minutes under the negative pressure during the casting process until the surface of the casting part is hardened and shaped, and then the casting part is taken out form the box after sufficient cooling. The invention has the advantages that the process changes the organizational structure of the casting part, enables the crystal grain to become fine, enhances the mechanical property of the casting part, and enables the chemical composition to be more qualified as well as the shelling falling of the coating layer of the casting part to be more thorough.

Description

technical field [0001] The invention relates to the technical field of lost foam casting technology, in particular to a lost foam casting technology that overcomes the prejudice of the prior art. Background technique [0002] The lost foam casting process is already a mature technology. The traditional lost foam casting process is to bond and combine foam models similar in size and shape to the castings to form a model cluster, brush the refractory layer and dry it, and bury it in dry quartz sand. In the box, after being vibrated, covered with plastic cloth, it is casted under negative pressure. After casting, when the plastic cloth does not move, reduce the vacuum degree and continue vacuuming for several minutes until the surface of the casting is hardened and formed, then stop vacuuming (The specific time for the vacuum extraction is determined by the condition of the casting, the purpose is to make the surface of the casting harden and form), uncover the plastic cloth, a...

AI Technical Summary

Problems solved by technology

The traditional lost foam casting process believes that in order to ensure that the box does not collapse, the vacuum degree must be reduced for several minutes while the plastic cloth does not move. This is a misunderstanding in the traditional lost foam casting process; moreover, the traditional lost foam casting process There is a large stress inside the casting after casting. In order to solve the shortcoming of large stress inside the casting, the traditional process adopts a separate aging treatment after the casting process is completed; Slower, part of the residual carbon element after the lost foam gasification is easy to infiltrate the casting from the outside to the inside, resulting in changes in the chemical composition of the casting, changes in the microstructure of the casting, and changes in performance, resulting in castings that do not meet the requirements