PRODUCT CATEGORIES

Vacuum Heat Treatment Furnace

Vacuum Sintering Furnace

Vacuum Brazing Furnace

Vacuum heat treatment of aviation impeller

In the aviation industry, a large number of high-strength, high-precision metal parts are required. The processing of these metal parts is inseparable from the heat treatment process. Among all heat treatment processes, vacuum heat treatment is widely used because of its excellent properties.

Directionally solidified superalloy is a kind of new material with good mechanical properties and low alloy density developed to meet the needs of high thrust-to-weight ratio aero-engines. In order to improve the structure and properties of the alloy, almost all of the directionally solidified superalloys need to be heat treated. The hot-end components of aero-engines produced by directional solidification technology, such as turbine rotors or stator blades, are mostly formed by precision casting, resulting in precision castings with no or small margins. In order to keep the heat-treated parts free from oxidation and depletion of alloying elements, the best option is to heat-treat under vacuum conditions.

Process example

The first-stage turbine rotor blade of aero-engine is a hollow structure, which is made of DZ4 directional solidification superalloy. A special cover plate (material GH3030) should be added to the hole on the end face of the blade crown, and the technical requirements are vacuum brazing for connection. The use of vacuum brazing furnace for high temperature vacuum brazing of blades is the best process under the existing conditions.

For vacuum brazing, 171 brazing filler metal brazing temperature is 1150-1200℃, holding time is 60-70min, and the cooling method is furnace cooling. After brazing, the surface of the blade is bright, the round root of the brazing seam is good, smooth and has been brazed through, and no defects such as brazing cracks are found.

The solution treatment of turbine rotor blades was originally only carried out in ordinary air furnaces, and there were serious oxidation and surface alloy elements depletion due to burning loss. The depth of the depleted layer was as high as 0.12mm. For the blade, the extension between the blade body and the tenon is not processed, and there is no machining allowance, that is to say, the surface quality of the blade is unqualified if the above phenomenon occurs. Secondly, the air furnace is used to treat the blade, and the heat treatment deformation is large, and the light transmittance of the blade profile exceeds 10%.

In order to improve the heat treatment quality of the blades, the RVGQ vacuum air quenching furnace produced by SIMUWU is used for solution treatment.

The gas quenching furnace produced by SIMUWU has the following characteristics:

(1) The furnace door and furnace bottom are equipped with heating elements, and high-flow gas nozzles are evenly distributed in the cylindrical heating chamber to avoid uneven heating and cooling.

(2) The control system adopts Siemens PLC, and all the actions of the furnace can be switched between automatic and manual, and there are interlocking protection devices. The PLC temperature control system has good control accuracy and repeatability, and can automatically display, record and print the control process and results.

(3) The equipment can control the gas partial pressure, and obtain a higher vacuum inflation pressure by backfilling argon. The vacuum working pressure of vacuum heat treatment can be adjusted within a certain range according to needs.

The air quenching cooling speed of the equipment has a wide adjustment range, and can be operated in the furnace equivalent to conventional furnace cooling, air cooling and oil cooling, which meets most of the requirements for vacuum air quenching of aerospace parts.

Process flow:

The heating temperature of the vacuum solution treatment was 1220°C. In order to reduce the thermal stress, the heating process of the workpiece adopts step heating, and the heating speed of each stage is slow heating, and the holding time is 2h. Selection of vacuum degree: 6.67×10^–¹Pa is used before the partial pressure temperature. Partial pressure is carried out at 900-1000 ℃, and high-purity argon is recharged into the vacuum heating chamber to obtain a higher vacuum inflation pressure, so as to avoid the evaporation of superalloys under vacuum and high temperature conditions, and obtain a bright surface. Generally 3 ~ 14Pa. Gas quenching pressure 3bar.

After the vacuum heat treatment of the turbine rotor blade, the parts are bright and silver-white, and there is no metal element depletion layer and no out-of-tolerance deformation. Excellent mechanical properties.

Vacuum furnace equipment selection: RVGQ series vacuum heat treatment furnaces produced by SIMUWU are high-quality products for vacuum heat treatment process. Good temperature control accuracy and temperature control uniformity ensure effective vacuum heat treatment process. SIMUWU specializes in the manufacture of vacuum furnaces, has more than ten years of relevant experience, and has a good reputation in the field of vacuum furnace manufacturing. The product line includes vacuum air quenching furnace, vacuum oil quenching furnace, vacuum brazing furnace, etc., which are widely sold in developed and developing countries.