A mold shell for precision casting titanium alloy

Abstract

The invention discloses a mold shell for precision casting titanium alloy. The mold shell is composed of 1 layer layer, 2 layers of transition layer, 4 layers of reinforcement layer and a sand layer between each layer, wherein the surface layer contains 200-400 Boron nitride powder, the sand layer between the surface layer and the transition layer is fused mullite sand with a particle size of 40-100 mesh; the first transition layer contains 200-400 mesh Y2O3 powder, and the second transition layer Contains 200-400 mesh Al2O3 powder, the sand layer between the first transition layer and the second transition layer and between the second transition layer and the reinforcement layer is fused mullite sand with a particle size of 40-80 mesh; The 4 reinforcement layers all contain bauxite, and the 3 sanding layers between the 4 reinforcement layers are coal gangue sands of 16-24 mesh.

Description

technical field [0001] The invention relates to the field of casting molding, in particular to the field of precision casting titanium alloys. Background technique [0002] Titanium is a new type of engineering metal material that rises rapidly after steel, iron, copper and aluminum. It has the characteristics of high strength, low density, corrosion resistance, non-magnetic properties, and good biocompatibility, and is more and more popular among people. In the early stage, it was mainly used in the military field, and now it is gradually expanding to the civilian field, and the growth is rapid. [0003] At present, the mold shells used for titanium alloy precision casting can be roughly divided into: graphite mold shells, tungsten surface ceramic mold shells, oxide ceramic mold shells, etc. Among them, the casting casted by the graphite formwork has a layer of carburized α brittle layer on the surface with a thickness of about 0.2-0.3 mm, which may cause crack generation ...

AI Technical Summary

Problems solved by technology

The tungsten surface layer investment casting mold shell α must be dewaxed by solvent, which is harmful to human health and pollutes the environment; in addition, the tungsten surface layer mold shell is roasted in a reducing atmosphere, and the mold shell deposited on the surface of the mold shell is dewaxed. The ash content of the material is difficult to burn off, and it is easy to react with liquid titanium during pouring, forming pores on the surface of the casting

Zirconia, yttrium oxide and other oxides that are less reactive with titanium liquid used in the surface layer and adjacent layer coating of oxide ceramic formwork have higher performance; the surface coating with yttrium oxide as filler has better casting performance , but yttrium oxide is prone to hydration, and its slurry is very sensitive to pH changes and is easy to gel

In addition, the oxide ceramic formwork cannot avoid the formation of an α-staining layer on the surface of the casting, and its thickness ranges from 0.02 to 0.2 mm.