Method for preventing blades of whole turbine impeller of high temperature alloy from under-casting

Abstract

The invention relates to a method for preventing blades of a whole turbine impeller of a high temperature alloy from under-casting. The method comprises the following steps: 1, preparing a whole turbine impeller wax mold through an integrated compression molding technology, wherein the wax mold is formed by a circular disc and the blades uniformly distributed on the periphery of the circular disc; and 2, carrying out shell making and dewaxing on the whole turbine impeller wax mold through a molten mold precision casting technology. The method is characterized in that: the tip part of each blade of the completed whole turbine blade wax mold is bonded with a length of a wax sheet with a certain shape and a certain size, wherein the shape and the size of each wax sheet are characterized in that the thickness is 0.5-3mm, the width is 5-30mm and the length is 5-30mm; and each wax sheet forms a "air storage bag" shell type cavity in the whole turbine impeller type shell after completing theshell making and the dewaxing of the whole turbine impeller wax mold. Compared with the prior art, the "air storage bag" structure can effectively prevent the blades from under-casting, and especially can prevent thin exhaust edges of the blades from under-casting. Nonmetals included by the blade tips can easily enter the "air storage bag" shell type cavities, so the inclusion case of castings can be improved. Embodiments prove that the casting qualification rate is improved over two times and the cost is reduced by over 50%.

Description

technical field [0001] The invention relates to a method for preventing blade undercasting of a high-temperature alloy integral turbine impeller, and belongs to the technical field of high-temperature alloy precision casting. Background technique [0002] Gas turbine engines have become an important prerequisite and bottleneck for the development of my country's aircraft and even large aircraft. Superalloys and their parts forming technology have always been called the heart of gas turbines and have been used to manufacture gas turbine hot end components. With the increasing demand for helicopters and drones in my country in recent years, the market for small and medium gas turbine engines is promising. The core component of the hot end of a small and medium-sized gas turbine - the "turbine" often adopts a superalloy integral turbine impeller structure. The integral molding of turbine disk and blade will inevitably put forward higher requirements for defect control and eve...

AI Technical Summary

Problems solved by technology

Its disadvantages are: first, the alloy is poured at too high a temperature, resulting in coarse grains inside the casting, and the actual mechanical properties decrease; second, the rise of the shell temperature increases the probability of shell breakout; third, the shell material is washed by the high-temperature melt The bottom is easy to fall off and non-metallic inclusions enter the casting; fourth, some castings are thin because of the blade, even if the combination of extremely high pouring temperature and shell temperature is used or even centrifugal casting is used, due to the "suffocation" of the blade end in the shell mold, local The phenomenon of under-casting of blades; Fifth, if centrifugal casting is used, special tooling and fixtures are required, and at the same time, the shell mold is required to have higher strength, which increases the difficulty of the process

Images