SU1518568A1 - Method of manufacturing runner for flancis turbine hydraulic machine - Google Patents

Abstract

The invention relates to metallurgy, and more specifically to the manufacture of impellers for radial-axial hydraulic machines. The purpose of the invention is to increase the operational reliability of the impeller. The method includes welding blades, heat treatment of the wheel, heating the lower rim and the middle part of the blades to 250-350 ° C at a speed of 100-300 ° C / h, air cooling and final machining of the wheel. The application of the method allows to increase the resistance to the formation of fatigue cracks and the operational reliability of the impeller. 1 il.

Description

The invention relates to hydraulic engineering, more specifically to the manufacture of impellers radial-axial hydraulic machines.

The aim of the invention is to noBbmie the operating reliability of the impeller by creating residual volumetric compressive stresses in the welded joint.

The drawing shows the wheel radial-axial hydraulic machines.

Example. Impeller material: blades and rim rolled steel sheet grade 06X12H3D; upper rim - casting of steel 06X12H3D-J1.

FIG. Figure 1 shows the working track manufacturing scheme. The impeller contains lower rim 1 and upper

rim 2, between which the blades Ze are installed with input edges 4 and output 5. The blades 3 abut on the outer rim 1 and ends 7 on the upper rim 2. On the blade x 3, in the places adjacent to the lower rim 1, electro-radiation heaters 8 are installed .

In the manufacture of the impeller, the machined blades 3 and the upper rim 2 are assembled by welding the rigid connections connecting them (not shown). Then the final welding of the blades 3 is carried out on the ends 7 with the upper rim 2. The heating of the upper rim 2 with the blades 3 is carried out using electrolysis heaters 8 before

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welding up to 175–25 C. Heating is carried out uniformly along the entire perimeter of the upper rim 2. During the heating process, the upper rim 2 with blades 3 is covered with asbestos cloth. Monitoring the ocynier heating temperature is made during the welding process. When the temperature drops below, no welding is allowed. Temperature control is carried out by thermocouples fipH- boiled to the blade m 3 (not shown in the drawing). Welding is performed by electrons of the CPU 51. Welding modes: electrode 4: current lee 130-150 A; Ice electrode force 5 Ice 160-170

The following heat treatment is carried out according to the mode: heating to 640 ± 10 C, {Shutter speed 15 h; heating rate 50 s / h; cooling rate at 2 ° C is 30 ° C / h; in the temperature range of 250-150 ° C, the cooling rate, after the cooling temperature in air.

The ends of the 6 blades 3 are machined along the interface with the lower rim 1, and then the lower rim is welded to the blades (similar to the welding of blades 3 with the upper rim 2) and the final heat treatment of the wheel.

The impeller is pre-machined, leaving an allowance of 10 mm per hundred. ron the diameter of the lower rim. The residual stresses are then measured in the indicated areas of the blades. The measurement is carried out by the low-destructive method (1.7 mm holes, 1.2 mm depth) with the help of special three-component tensor sockets with 8 blades x (through 1 blade).

Before final machining of the impeller, the lower rim 1 and the middle part a of the blades 3 between the output 5 and the input 4 chrome

Kami heat electroradiation heaters 8 to 280-300 s. Heating is carried out to a predetermined temperature for 3x hours (with speed), followed by exposure for three hours to equalize the temperature around the rim circumference with natural air cooling. Sections, wheels, not exposed places

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A method of manufacturing an impeller radial-axial hydraulic machine, which includes welding the blades with upper and lower rims and subsequent heat treatment of the wheel, characterized in that, in order to increase operational reliability by creating residual volumetric compressive stresses in the welded joint, after heat treatment the wheels heat the lower rim and the middle parts of the blades between the output and the entrance edges at a speed of 100-300 C / h to temperan heating are electrically operated for 55 rounds of 250 to 350 ° C, cooled on air heaters 8, ceiling elements Okhla, "de no lack.

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The final machining of the impeller and measurement of residual stresses in all 15 blades x at the weld seam adjacent to the lower rim at a distance of 120 mm from the end edge of the output edge and additionally at distances of 250 and 400 mm from the end edge of the output edge at two blade x. The strain measurement is made by the ISD-3 static deformation meter.

For comparison, the manufacturing of the impeller of the hydraulic machine is carried out according to the prototype method, which includes the welding of blades with lower and upper rims and heat treatment of the wheel.

As a result of using the proposed method for the manufacture of hydraulic impellers, it has been established that residual compressive stresses are observed in the middle zones of the blades, which are 20-30 St1a. In the middle zones of the blades of wheels manufactured by a known method, residual tensile stresses are observed and they are 120-200 tffla on the working side and 120-250 MPa on the non-working side of the blade.

The application of the proposed method allows to significantly increase the operational reliability (over 5 years) of the impeller operation by creating residual volumetric compressive stresses in the welded joint. In addition, the resistance to the formation of fatigue cracks and destruction of the blades during shutdown of hydraulic machines is significantly increased.

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Claims (1)

40 claims five 0 A method of manufacturing an impeller radial-axial hydraulic machine, which includes welding the blades with upper and lower rims and subsequent heat treatment of the wheel, characterized in that, in order to increase operational reliability by creating residual volumetric compressive stresses in the welded joint, after heat treatment the wheels heat the lower rim and the middle parts of the blades between the exit and entrance edges at a speed of 100-300 C / h are temperatur and the wheel is machined.