A gating system for thin-walled cylindrical parts and its precision casting method

Abstract

The invention discloses a pouring system for thin-walled cylindrical parts and a precision casting forming method thereof. A wax tree, the surface of the wax tree is covered with a mold shell. The method of precision casting includes forming a mold without parting surface; coating of the mold; preheating of the mold; smelting and pouring; cleaning of castings; heat treatment, etc. The invention can replace the currently widely used centrifugal casting molding method, can significantly save the master alloy, improve the yield, reduce the harsh requirements for equipment, environment and personnel, reduce the machining amount, and the cost is only 60% of the centrifugal casting cost, Due to the large amount of Stellite inner bushing and the large number of varieties every year, it has very considerable economic benefits.

Description

technical field [0001] The invention belongs to the precision casting of Stellite alloy, in particular to the precision casting forming method of a wear-resistant Stellite inner bush for a valve core and a valve stem of a steam turbine. Background technique [0002] The steam turbine spool parts require that the sealing surface has a certain hardness to ensure its wear resistance and prolong the service life of the parts. For this reason, the methods commonly used at present are 1) surface nitriding treatment; 2) adopting the process of plasma spray welding to surfacing Stellite alloy on the workpiece surface. 3) After the overall inner lining of Stellite alloy is interference-fitted with the outer sleeve of the sleeve, the end faces are sealed and welded to achieve the functions of sealing and wear resistance. [0003] Among the above-mentioned several processes, the surface nitriding treatment process is simple, but the sealing performance and wear resistance are relative...

AI Technical Summary

Problems solved by technology

[0003] Among the above several processes, the surface nitriding process is simple, but the sealing performance and wear resistance are relatively poor

Plasma spray welding technology needs to design and manufacture a series of high-performance inner hole plasma spray guns according to different inner hole diameters, and has strict requirements on the operator's technology and the surrounding environment, the process is complicated, and the yield is very low.

[0004] The one that is developing well now is the integral Stellite inner bushing made by the centrifugal casting method. Only a few manufacturers have the production capacity of this product, and the price is expensive.

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