FR2575185A1 - Process and device for the production of deposits and refills of metallic, metalloceramic and ceramic materials on a substrate - Google Patents

Abstract

The substrate 10 is softened very locally with the aid of a source of heat 14 such as a transferred or semitransferred plasma torch and at the same time the refilling material is projected hot and at a high velocity, for example by means of a detonation gun 22 using a propylene-air mixture, onto the locally softened substrate. The detonation gun and the plasma torch are independently controllable, and this makes it possible in particular to avoid a partial dilution of the substrate in the projected material.

Description

Method and device for making deposits
and reloading of metallic materials, metallo
ceramics and ceramics on a substrate
The present invention relates to a method making it possible to produce deposits and reloads of metallic, metalloceramic and ceramic materials on a substrate. The invention also relates to a device for implementing this method.

 Various methods are known for making metallic, metalloceramic and ceramic deposits or reloads on a metal substrate.

 For example, hot spraying processes, commonly called "shooping", carried out in particular by means of flame guns, make it possible to obtain coatings under advantageous economic conditions. These methods are well known and used industrially. Their main drawback is linked to the fact that the projectat-substrate attachment is essentially mechanical and takes place with very little or even zero chemical diffusion. 4th addition, the deposits produced by these processes are always porous.

 The use of a blown plasma torch instead of a flame gun makes it possible to improve the quality of the deposits and the attachment of the projectat to the substrate, a partial metallurgical diffusion participating in certain cases in this attachment. In addition, there is a significant decrease in the porosity of the coatings.

 The use of a plasma torch blown in an enclosure under vacuum and under a controlled atmosphere makes it possible to further improve the quality of the coatings obtained.

 Another known method of hot spraying uses a detonation gun by means of which small quantities of powder are sprayed at high speed (about mach 2) by the explosion of an acetylene-oxygen mixture. The deposits thus obtained are well attached to the substrate and their porosity is very low.

However, this method has the drawback of requiring a heavy installation located in an enclosure protecting personnel against intense noise and the risk of explosion.

 In all existing hot spraying processes, the coatings obtained always have the drawback of being fragile to a greater or lesser degree on impact.

 Other methods of reloading which are similar to welding are also currently used.

In this category, one finds the processes of reloading with the arc, under protective gas, by means of wire or rods as well as the processes of reloading by plasma of transferred or semi-transferred arc. In this case, the filler material such as a cobalt-based alloy is in the form of a bath
Liquid protected by plasma gas and, therefore, protected from oxidation. The reloads obtained by this process are waterproof and their attachment to the substrate is excellent since it implements a metallurgical dilution between the projectat and the substrate.

 These plasma recharging processes of transferred or semi-transferred arcs, however, have a serious drawback. In fact, there is a sometimes significant dilution of the substrate in the molten reloading bath which, taking into account the generally less noble character of the base metal of the substrate compared to the recharging alloy, can degrade the mechanical qualities and reloading chemicals very sensitively. This drawback is all the more annoying since the dilution rate is very difficult to control. In addition, obtaining a well-melted liquid bath also leads to excessive heating of the part to be recharged, which can be prohibitive when it is desired to locally recharge large parts such as cutting or stamping tools. indeed, significant mechanical stresses are thus induced due to thermal heterogeneities. These constraints lead to deformations, possible breakages, cracks and cracks which develop - in the reloading during cooling.

 The subject of the present invention is precisely a method and a device making it possible to produce fillings and reloads of metallic, metallo-ceramic and waterproof ceramic materials with high mechanical characteristics and not having the drawbacks of existing methods and devices.

 To this end and in accordance with the invention, a method is proposed for producing deposits and reloading of metallic, metallo-ceramic and ceramic materials on a substrate, characterized in that it consists in very locally softening the substrate to using a heat source and simultaneously projecting the material to be deposited, hot and at high speed, by means adjustable independently of said heat source, onto the locally softened substrate.

The invention also relates to a device for producing deposits and reloading of% metallic, metalloceramic and ceramic materials on a substrate, characterized in that it comprises a heat source intended to soften very locally the substrate, and adjustable means independently of said source for simultaneously projecting
The material to be deposited, hot and at high speed, on the locally softened substrate.

 Preferably, the heat source is constituted for example by a semi-transferred pla-sma torch, by a laser or by an electron gun and the means for projecting the material to be deposited are constituted for example by a detonation gun, by a blown plasma projection torch - or by a flame gun.

 A preferred embodiment of the invention will now be described, by way of nonlimiting example, with reference to the appended drawing in which the single figure is a perspective view schematically showing the recharging of the planar surface of a part using a device according to the invention.

 In the figure, the part to be treated is designated by the reference 10. This part is a metal part which can be of any shape, the parallelepiped shape shown in the figure being given only by way of example.

 Opposite the face of the part 10 on which it is desired to deposit a ceramic, metallo-ceramic or metallic material such as a cobalt-based alloy, the device 12 according to the invention is placed. By way of example, this device 12 is arranged in the figure opposite the upper face 10a of the part 10, which in this case constitutes the face to be recharged.

In order to effect the reloading of at least part of the surface 10a using the device 12, the entire part of the surface 10a to be reloaded is scrolled in front of the device 12. To this end, it is possible to- for example move part 10 in a movement
straight line represented by arrow F in the figure, the device 12 remaining fixed. Of course, it is also possible to carry out the scanning of the surf-ace lOa
by immobilizing part 10 and moving the device
tif 12. Depending on the shape of the surface 10a to be recharged,
it will also be understood that the relative scrolling between
the part and the reloading device may not
not be straight but circular or any other
form.

According to the invention, the device 12
comprises a heat source constituted in the embodiment represented by a semi plasma torch
transferred or transferred 14 emitting a transferred arc 16 surrounded by a column of protective gas 18. The arc
transferred 16 locally heats the substrate to fu
sion of a lenticular area 20, the depth of this
zone can be adjusted at will by acting on the
plasma torch 14.

The device 12 according to the invention further comprises means for projecting the material to be deposited, which are constituted in the embodiment shown
felt in the figure by a detonation cannon 22. The high speed projection of the molten powder of re
loading is shown at 24, following the arrow. The impact of the molten powder on the substrate is shown
in 26. This impact merges with zone 20 melted by
the transferred arc 16.

Thanks to the device which has just been described,
the melting of the substrate can be very localized and does not have
make only a small thickness under the effect of a rule
appropriate age of the plasma torch 14. Furthermore, thanks to its temperature and its energy due to the vi
projection size, the reloading powder comes
become embedded, become embedded in the softened zone of the subs t rat.

This completely eliminates the risk of di
partial release of the substrate in the projected alloy
whose purity is fully preserved and, consequently, the mechanical, chemical qualities, etc. Furthermore, the protection provided by the gas coming from the plasma torch prevents any oxidation or nitriding of the materials used. It is thus possible to reload very localized, on large parts by eliminating the risks associated with thermal heterogeneities, as well as reloads on small parts without risk of deterioration of the substrate.

 In summary, the device according to the invention therefore has the combined advantages of recharging by transferred plasma and recharging by detonation gun, without having the disadvantages.

 In addition, the fact of very locally heating the substrate by means of a t-ransferred arc plasma makes it possible to use a detonation gun less efficient than the acetylene oxygen cannons usually used. In particular, it is possible to use a cannon consuming a propylene-air mixture, which eliminates the risks of explosions and very significantly reduces the cost of the installation.

 Finally, it should be recalled that the invention is not limited to the case where the heat source is constituted by a transferred plasma torch and where the material to be deposited is projected by means of a detonation gun, but also applies, by way of nonlimiting examples, in cases where the heat source is constituted by a laser or by an electron gun and in cases where the material to be deposited is projected by means of a blown plasma torch or a flame gun.

Claims (5)

 1. Method for producing deposits and reloading of metallic, metallo-ceramic and ceramic materials on a substrate, characterized in that it consists in very locally softening the substrate (10) using a heat source (14 ) t14) and simultaneously projecting the material to be deposited, hot and at high speed, by means (22) adjustable independently of said heat source, onto the locally softened substrate.  2. Device for producing deposits and reloading of metallic, metallo-ceramic and ceramic materials on a substrate, characterized in that it comprises a heat source (14) intended to very locally soften the substrate (10 ), and means (22) adjustable independently of said source for simultaneously projecting the material to be deposited, hot and at high speed, onto the locally softened substrate.  3. Device according to claim 2, characterized in that the heat source (14) consists of one of the following devices: semi-transferred plasma torch, laser transferred plasma torch, electron gun.  4. Device according to any one of claims 2 and 3, characterized in that the means (22) for projecting the material to be deposited are constituted by one of the following devices: detonation gun, projection torch at plasma blast, flame gun.  5. Device according to any one of claims 2 to 4, characterized in that the heat source (10) is a plasma torch and in that the means (22) for projecting the material to be deposited are constituted by a detonation cannon consuming a propytene-oxygen mixture.