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-ot.-The application for a Patent has become void.
This print shows t e cation as it became open to publio inspection under Section 91 (3) (a) af the Acts.
- PATENT SPECIFICATION
Convention Date (Germany): Aug. 29, 1930. 3 929 1A Application Date (in United Kingdom): Aug. 7, 1931. No.22,477/31.
[5 Complete not Accepted.
- Improvements in and relating to Means for Preventing the drosioni I,- X X, - of i -atals, We, INTERNATIONAL GrEEBRnAL= ELECTRIC COMPANY, INCORPORAT:D, of 120, Broadway, New York, United States of America, Merchants,- a Corporation- organised under the laws of the State of New York, United States of America, (Assignees of ALLGEhMEIBIE E LEETRICITXTSGESELLSO.HAIITM, of Friedrich Karl-Ifer 2/4, Berlin, N.W., Germany, a German Company), do hereby declare the nature of this invention and in what manner the same is to be performed,. to be particularly described and ascertained in and by the following statement:-
It has been proposed to provide the surface of metals which undergo considerable wasting at certain points owing to erosion, with a coating of a resistant metal. This has been effected for example 'by plating the foundation metal with a resistant metal or by welding-on the ennobling metal after it had been reduced to a liquid condition. Plating, however, can be carried out only on smooth pieces of work, such as sheets, plates and bars. The method of welding the liquefied ennobling metal requires very high temperatures, involves uneven heating of the workpiece and causes stresses 'which give rise to serious alterations in shape and deformation of the $: whole workpiece or the welded ennobling metal cracks. Both these methods are therefore unsuitable for the form given to intricate workpieces such as turbine blades with reinforced and sharpened inlet edge.
Owing to its high initial cost, it is not practicable to resort to the proposal in respect of turbine blades for example, that the whole workpiece should be made of high-quality and erosion-resisting metal.
To obviate these disadvantages, it is proposed according to the present invention to coat the foundation metal with wear-resisting metals such as alloys of [Piree 1/-] manganese, chromium, tungsten, molylbdenui,- c-obalt or the like [by the spraying method, for example by-means of a suitable spraying,guun. Ins order to facilitate the bonding process between the foundation metal and the ennobling metal, the former may be heated to a high. temperature prior to the spraying 15 of the ennobling metal; alternatively, a heat treatment may be applied after the operation of spraying the ennobling metal has been completed. The heat treatment in either case is preferably carried out 60 in a neutral or reducing atmosphere in order to avoid the oxidizing of the foundation and ennobling metals during the course of the treatment.
Should the foundation metal and the 65 ennobling metal exhibit slight tendency to alloy, the foundation metal may be provided in a known manner (before the ennobling metal is applied) with a coating of a metal which readily forms an alloy with the ennobling metal as well as with the foundation metal.
The process forming the sabject-matter of the present invention is particularly suitable for use in the case of turbine 7t blades, when the blades can be coated, either wholly or in part for example at the inlet edge with an ennobling metal.
The use of the subject matter of the present invention is nevertheless not 80 restricted to turbine blades, as it is applicable to all cases where it is a question of providing a lower quality constructional metal at highly-stressed parts with an ennobled surface.
Having now particularly described and 85 ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we