SU873696A2 - Method for making blades - Google Patents

Description

one

The invention relates to the field of engineering technology and can be used in the manufacture of compressor and turbine blades.

According to the main author. St. No. 8,26631 discloses a method for manufacturing blades, which consists in heating the workpiece, closed die forging in superplasticity mode, heat treatment, machining and twisting the pen 1.

However, the use of heat treatment before twisting leads to a decrease in the product performance characteristics due to high residual stresses arising during the spinning process, which is also due to the increased strength characteristics and the low plasticity characteristics of the heat-treated material. This reduces the fatigue strength of the products.

The aim of the invention is to increase fatigue strength. The goal is achieved by the fact that the B method of manufacturing blades, including heating of the workpiece, closed die forging in superplasticity mode, thermal, mechanical processing and the subsequent twist of the feather, heat treatment is performed after twisting the machined blade feather.

The proposed method is as follows.

The original bar stock is coated with glass grease, heated and subjected to 5 closed die forging in superplasticity mode.

The resulting semi-finished product has an allowance along the pen profile of 0.1-0.2 mm. The allowances are chosen based on the capabilities of the straining and mechanical processing, taking into account the surface cleanliness, the depth of the defective stamping layer, the accuracy and stability of the blade base during the processing. Stamping, passing a series of auxiliary 15 operations (removal of glass grease, barbs and altered layer), are sent to mechanical processing.

After machining, the pen is twisted on the bending tool and dried, heat treatment is performed.

Conducting heat treatment at the end of the blade manufacturing process improves the machinability of the stamping material, and this drastically reduces the laboriousness of the process by reducing the consumption of the cutting tool and increasing the productivity of the treatment. The required forces for over 30 twists of the pen are reduced by reducing the strength and

increase the plasticity of the material that did not pass the second annealing. This will entail a decrease in the level of residual stresses arising from the rotation during twisting, which will significantly increase the service life of the blades.

Conducting heat treatment after machining and twisting the pen will significantly reduce the level of residual stresses arising during machining, and most importantly, almost completely eliminate the effect of internal stresses arising from the twist of the pen on the performance characteristics of the blades, in particular, on their endurance.

The decrease in the level of residual and internal stresses after heat treatment is due to the fact that when the return processes are accelerated, as a result of which the residual micro and macro stresses are eliminated.

Example. The rod blank (material BT-9; size 0 14X34) is coated with EVT-24 glass grease and heated to a temperature of 950 ° C. Then, the heated billet is placed in a closed stamp, OiCHa by an inductor, which provides a temperature in the deformation zone of 950-960 ° C, and is stamped at a constant temperature with a deformation rate of 3-5 mm / min. In the resulting compressor blade with a non-twisted nib and with an allowance

along the 0.1 mm and 0.2 mm profiles, the glass grease, burrs and the altered layer are removed. After that, the machining is carried out.

The treatment is carried out in the following sequence: first the lock is processed, and then, using it as a base, the profile of the pen is polished.

After processing, the profile is monitored on POMKL devices.

The twist of the pen is made on a profile-bending device, after which the blades, having passed the final control on the geometry and quality of the twist, are transferred to heat treatment.

The heat treatment is carried out as follows. Blades mounted on stands to eliminate nicks and warping profiles are loaded into an oven with a temperature of 530 ° C and held for 6 hours.

The medium in the furnace can be any, since the process of forming an altered layer on the surface of the parts proceeds at temneterours of more than 700 ° C, and a layer with a thickness of not more than 0.01 mm forms in 2 hours.

In order to determine the health of the products, the blades were manufactured according to the proposed method and tested on a shaker table under various loads. The results are shown in the table.

As can be seen from the above results, the use of the proposed method of manufacturing blades provides the following advantages compared with the known ones:

increase in product life by 10-15% by increasing fatigue strength;

reducing the labor intensity of manufacturing the blade by improving the workability of the material.

Claims (1)

1. USSR author's certificate No. 826631, cl. At 21K 3/04, 1977.