DE1055332B - Process for the manufacture of metallic workpieces, e.g. B. turbine blades, with longitudinal ducts - Google Patents

Description

The invention relates to a method for manufacturing metallic workpieces, e.g. B. turbine blades, with one or more long channels by hot forming a blank according to cross-sectional content and / or shape, the metallic filler cores of which are introduced into correctly positioned bores Workpiece have adapted deformation properties and can be removed by a leaching process are.

In this context, hot forming is basically understood to mean any hot working that leads to deformation of the workpiece blank according to cross-sectional content and / or shape, preferably extrusion, but also rolling, forging and drawing.

Insofar as previously leached filler cores were used with deformation properties that were as matched as possible to the workpiece, the Properties differ in that the core could be attacked by an acid, the workpiece but less or practically not. So was z. B. chosen a filler core made of soft steel, if the workpiece was made of stainless steel. The deformation properties are therefore not fully matched of workpiece and core material naturally make it difficult to control the duct cross-sections in their relationship to the total cross-section during deformation. The material drilled out goes to waste, even the leached filling goes to waste, in the full amount that corresponds to the content of the channels. The leaching of the relevant core mass requires a not inconsiderable one Time and also an appropriate amount of acid.

It is known per se to subsequently produce a cylindrical bore in a workpiece blank insert a sleeve into this hole and finally press a core into it. For the same Like the workpiece, the core is only selected if it is an integral part of the finished, solid workpiece, e.g. B. valve, forms, and it is between a Core and shell part of the workpiece is a ring layer made of a highly conductive material, e.g. B. copper, accommodate. Also - as already mentioned - in this case A ^ is not a ring-shaped one, but one full bore made in the workpiece.

Furthermore, a known proposal for the production of thin-walled tubes is between a Jacket made of steel or a steel alloy and a core block, which is also made of steel or a steel alloy consists, an insulating layer, e.g. B. oxide layer, aluminum bronze od. Like. To provide and after an extrusion of this unit to release the cover tube produced from the core rod, so that both parts can be reused individually. When arriving

Method of manufacture

of metallic workpieces,

z. B. Turbinensctiaufein, with long channels

Applicant:

Henry Wiggin & Company Limited,
London

Representative: Dr.-Ing. G. Eichenberg, patent attorney,
Düsseldorf, Cecilienallee 76

Claimed priority:
Great Britain 29 April 1954

Alexander Barbour Graham,

Thornliebank, Glasgow (Great Britain),

has been named as the inventor

Applying this method to workpieces with several longitudinal channels, however, the output cavities would have to be in turn can be generated by making full bores. In addition, in each case there is a to expect firm adhesion of the core or cores in the deformed workpiece. The removal of the or the kernel therefore encounters corresponding difficulties.

According to the invention, a core of the obtained by electroerosive, annular drilling is now Workpiece together with a bushing body made of leachable material and placed in the ring bore used as filling.

The production of the annular bores according to the known method of electrical discharge machining offers various advantages within the scope of the invention. One time, holes can be drilled using electrical discharge machining Manufacture of very small diameter, with the result that little filler is used too are needed and thus also, the time required for later leaching is reduced to a minimum can be. In addition, the materials used to manufacture turbine blades Made of difficult-to-machine, heat-resistant and chromium-nickel alloys with small amounts of Titanium and aluminum exist, the machining of which by electroerosion compared to other machining

809 790/182

Claims (2)

Longitudinal processes, such as drilling or milling, are shortened or made easier. The filler is expediently introduced into the annular bore around the core as a preformed metal sleeve. Here, the malleability of the liner material should essentially correspond to the malleability of the material of the workpiece during hot forming. Since it is to be leached out again after hot forming to create the final channels or cavities in the workpiece, it must at least be more easily attacked by acid than the workpiece itself in order to prevent it from being damaged in any way when the filler is leached out. The bore is preferably produced as an annular blind hole. This maintains the cohesion of the core with the workpiece, which largely reduces the risk of inaccuracies due to insufficient flow of the filler. After the hot forming has taken place, the workpiece is then cut up; as a result, the filler sleeve is exposed at both ends and can consequently be leached out from both ends. But it is also possible to produce a continuous annular bore and to use the resulting core to fill the bore before the hot forming. EXAMPLE Using tubular brass electrodes, ring bores approximately 0.95 cm in outside diameter and 13.97 cm in depth were formed in a cylindrical blank made of a heat-resistant chromium-nickel alloy 9.21 cm in diameter and 15.24 cm in length were slightly larger than the electrodes used to make them. Tightly fitting tubular filler cans were inserted into these bores, the ductility of which during extrusion essentially corresponded to the ductility of the blank material. An alloy consisting of iron, manganese and titanium served as filler. Then / the blank was then heated to a temperature of about 1200 ° C. and introduced with its closed head end into an extrusion press, in which it was shaped into a blade. Here, the filler cans were lengthened, their cross-section reduced and their cross-sectional shape changed. The extruded workpiece was then cut into short pieces with the filler-free front end falling off. After leaching out the filler in boiling acid, the cores could be removed from the bores, whereby suitable longitudinal channels were formed for the passage of the coolant. Another hot or cold reduction or ίο -forming, z. B. by hot rolling, can be done before or after the removal of the filler and the cores. In the latter case, an intermediate filler, e.g. B. in cold deformation, a plastic can be used in the holes to a. Prevent squeezing. Patent claims. 1. A method for manufacturing metallic workpieces, e.g. B. turbine blades, with a or several longitudinal channels by hot forming a blank according to the cross-sectional content and / or shape, the metallic filler cores of which are introduced into the correct position for the workpiece have matched deformation properties and can be removed by a leaching process are, characterized in that one obtained by electroerosive, annular boring Core of the workpiece together with a sleeve body introduced into the ring bore Leachable material is used as the filling. 2. The method according to claim 1, characterized in that the inserted into annular blind holes Filler can by cutting the thermoformed workpiece at both of them Ends exposed and leached from both sides. Considered publications: German Patent No. 560,343;
British Patent No. 671,247; Swiss Patent No. 176 097; U.S. Patent Nos. 1980716, 2,093,775; "Machinery", Vol. 80, February 21, 1952, p. 322; "American Machinist," 3. September 1951, pp. 194/95, and March 3, 1952, pp. 136 and 138; "ETZ-B", No. 6, June 21, 1953, p. 195.