RU2380209C1 - Method for manufacturing of hollow blade - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention is related to methods for manufacturing of hollow turbine blades and may be used in aviation and power industry. Two halves of blade are shaped with allowance along contour. Airfoil portion of one of specified blade halves is arranged as a whole with tail. Blade halves are assembled and welded by melting method. On completion of welding, hot straightening of blade is carried out in die with deformation of welded joint with extent of at least 50%.

EFFECT: reduced labour intensiveness of hollow blades manufacturing and their improved accuracy.

2 cl, 1 dwg

Description

The invention relates to methods for the manufacture of composite turbine blades and blades and can be used in the aviation and energy industries.

There is a method of manufacturing a hollow blade by molding each of the two halves of the blade, assembling them and diffusion welding between them, twisting the assembled blade (see, for example, AS USSR No. 487707, B21K 3/00. Published 15.10.75. Bull. No. 38).

The disadvantage of this method is the high complexity of manufacturing associated with the preparation of the surface for welding and diffusion welding.

Closest to the proposed invention is a method of manufacturing a hollow blade from steels and alloys, comprising forming two of its halves, a feather of one of which is performed in one piece with a shank, assembling and welding between them (see RF Patent No. 2005105904. A method of manufacturing a hollow blade for turbomachines. Publish. 08/10/2006. Bull. No. 22).

This method is also time-consuming and requiring the use of special equipment for diffusion welding and preparation of a fine-grained alloy structure, since diffusion welding is carried out under conditions of superplasticity of the alloy.

The technical result, the achievement of which the claimed solution is directed, is to reduce the complexity of manufacturing hollow blades and increase their accuracy.

The specified technical result is achieved by the fact that in the method of manufacturing a hollow blade of steel and alloys, including the molding of two of its halves, the feather of one of which is performed in one piece with a shank, they are assembled and welded together, the halves of the blades are molded with an allowance along the contour, welding carried out by the melting method, and after welding, hot straightening of the blade in the stamp is performed with the deformation of the welded joint with a degree of at least 50%.

In the method, if there are internal stiffening ribs in the blade, they are stamped on one of the halves and welded on the other.

The use of fusion welding and subsequent hot dressing with deformation of the welded joint can significantly simplify the assembly process for welding and the welding itself; provide high accuracy of geometric dimensions, obtaining a fairly uniform structure and mechanical properties of the glory in the product.

The relative degree of deformation of the welded joint with a degree of at least 50% ensures welding of possible welding discontinuities and the achievement of the physicomechanical properties of the welded joint at the level of the base metal (see Forging of large forgings, results of a study of technological conditions. / Ed. By V.N. Trubin, I.Ya. Tarnovsky. - M.-SPb .: Mashgiz, 1962 .-- 224 p.).

Welding stiffeners with feather blades provides high strength composite blades.

The method is as follows.

First, one half of the blade, including a shank and a feather with stiffeners, is obtained from a measured bar stock of diameter D and length L by hot stamping on a hammer or press. The other half of the scapula, depending on the thickness and size of the pen, is obtained either by hot stamping or by cold cutting - by stamping.

After preliminary cleaning and machining with preparation of the edges of both halves of the blades for welding, they are assembled and welded using one of the fusion welding types (depending on the grade of alloy) with the formation of a weld bead with a height exceeding half the thickness of the feather part of the blade at the welding place, since the next the deformation of the welded joint during hot dressing should be at least 50%.

Then, the welded blade is heated in the furnace to the temperature of hot deformation and the die is straightened to the final dimensions of the product and with the relative deformation of the welded joint with a degree of at least 50%. After that, the blade is transferred to the thermal and final machining.

In a single or small-scale production, half of the blade, including a shank and a feather with stiffeners, is obtained by free forging with subsequent preliminary machining. The other half of the blade - the cover - is cut out in the form of a flat reamer from the sheet, and its twist is done manually. After the assembly and welding of the blade, it is heated to the forging temperature, the pen is twisted to the final dimensions and the forged welds in the underlay tool (dies).

A specific implementation of the method is considered on the example of the manufacture of a new generation hollow fan blade of a gas turbine engine from VT 8 alloy.

The hollow fan blade consists of a feather (1), a shank (2) and a cover (3).

The forging of one half of the blade, including a feather (1) with an internal diagonal rib and a shank (2), was made by stamping on GKShP with a force of 35 MP from a stepped round billet with step sizes: 120 mm in diameter 30 mm long and 50 mm in diameter 400 mm long . A stepped shaft billet was obtained by hot upsetting on a gas condensate field from a rod with a diameter of 50 mm of VT 8 alloy.

Heating for planting and stamping was carried out in a heating electric furnace at a temperature of 1100 ° C, and hot molding in the temperature range of 1100-950 ° C.

The blade cover was made of a 2 mm thick billet by cold stamping on a 0.25 MN press.

After hot stamping, annealing and pickling were annealed. Then both the workpieces were machined with the preparation of the edges for fusion welding. After that, the blade was assembled, installed in the conductor and conducted Inp welding with a tungsten electrode in an inert gas (argon) with filler material of the same composition (VT 8) (Inp welding with an inert gas And non-consumable N electrode with an additive - Sec. GOST 14771) . With the formation of a weld bead 3.5 mm high above the surface of the feather blade.

Then the blade was removed from the conductor, the weld seam was cleaned (if necessary) and transferred to the forging and stamping shop for hot dressing.

After heating the blades in an electric furnace to a temperature of 980 ° C, it was hot straightened in dies on a 25 MN hydraulic press. At the same time, all welds were deformed with a degree of more than 50% until the entire surface of the pen was aligned and twisted.

The claimed method in comparison with the prototype allows to simplify the technology and reduce the complexity of manufacturing the blades. Provide high quality finished product.

Claims (2)

1. A method of manufacturing a hollow blade from steels and alloys, comprising forming two of its halves, the feather of one of which is integral with the shank, assembling and welding among themselves, characterized in that the molding of the halves of the blade is made with an allowance along the contour, welding is performed by melting , and after welding, hot straightening of the blade in the stamp is performed with the deformation of the welded joint with a degree of at least 50%. 2. The method according to claim 1, characterized in that in the manufacture of a hollow blade with internal stiffening ribs, the latter are stamped on one half of the blade and welded on the other half of the blade.