ZTC4 alloy is a kind of α-β cast titanium alloy with moderate strength. It has good casting performance, welding performance and corrosion resistance. It is the most widely used cast titanium alloy at home and abroad. The alloy can be used under annealing or hot isostatic pressing, and can work under 350℃ for a long time. It is suitable for manufacturing static aviation structural parts, such as casing, bracket, shell, frame, turbocharger impeller, etc.

ZTC4 smelting and casting process

(1) Smelting process

The parent alloy ingot is smelted twice in the vacuum consumable electrode arc furnace, or the large ingot is smelted twice in the vacuum consumable electrode arc furnace and the bar material removed the surface oxide is forged by the blank as the parent alloy ingot.

(2) Casting process

The mother alloy ingot was used as consumable electrode and re-melted in a vacuum consumable electrode arc shell furnace. Gravity casting or centrifugal casting was adopted according to the shape, size and weight of the casting. Due to the use of shell furnace smelting, cast titanium metal liquid superheat is low; feeding capacity is worse than cast steel, generally adopted centrifugal casting. In this way, metal liquid filling cavity and casting shrinkage can reduce casting defects, refine grain size and improve performance.

Because titanium is a highly chemically active metal, it must react with various molding materials commonly used at present in the molten state, resulting in the hard and brittle reaction layer (usually called α contamination layer) formed on the surface of the casting with oxygen, carbon and nitrogen, resulting in adverse effects on the mechanical properties of the alloy. Therefore, the casting of titanium and titanium alloy must be used to melt titanium inert special casting. At present, the casting models used in the industrial production of titanium are: machined graphite type, tamped (graphite) type, graphite melt model shell, refractory metal