CN1371307A

CN1371307A - Thermal spraying equipment

Info

Publication number: CN1371307A
Application number: CN00812287A
Authority: CN
Inventors: 迈克尔·W·塞茨
Original assignee: METALSPRAY INTERNATIONAL LC
Current assignee: METALSPRAY INTERNATIONAL LC
Priority date: 1999-07-29
Filing date: 2000-07-27
Publication date: 2002-09-25
Anticipated expiration: 2020-07-27
Also published as: AU5840600A; WO2001008810A1; JP2003505599A; CA2379902A1; CN1153629C; EP1210180A1

Abstract

Thermal spraying apparatus comprises a spray head defining a nozzle with a throat (132) through which gas under pressure can be supplied. First and second guides are provided to guide feedstock wires (124) towards a point of intersection in or adjacent an end of the throat, preferably at an angle of between 45 and 90 degrees. The gas is forced through the throat at high pressure, preferably at a pressure sufficient to cause supersonic flow, thereby generating a finely atomised spray of molten feedstock material. The feedstock guides can take the form of drilled tubular inserts, or inserts with grooves which are received in cavities in body halves of the spray head.

Description

Thermal spraying equipment

Background of the present invention

The present invention relates to be used in substrate, producing the thermal spraying equipment and the thermal spray method of corrosion resistant and/or hard coating.

International application WO has described a kind of thermal spray method and apparatus of above-mentioned general type for No. 98/00574.

The purpose of this invention is to provide method and apparatus as the development of known method and equipment.

Summary of the invention

According to the invention provides a kind of thermal spraying equipment, it comprises a nozzle, and this nozzle limits a throat with an import and an outlet, and the gas flow with the axis alignment of throat, makes gas can deliver to import under pressure; At least the first and second guidance, they arrange guide respectively raw material thread by import towards one in the throat end or the crosspoint of contiguous throat end; A power supply is arranged to such an extent that be connected in raw material thread, so that causing electric arc between the raw material thread in throat; And a compressed air source, to arrange to throat's supply air, described guidance is arranged to such an extent that make raw material thread point to the crosspoint, thus the angle between limiting 45 ° and 90 ° between the raw material thread.

Described guidance is preferably arranged to such an extent that make the angle that limits between the raw material thread be approximately 60 °.

Nozzle can be made of first and second bodies, half one, and each body half one limits a part of throat.Throat is taper between import and outlet generally.

Guidance can be included in each hole that forms in body half one, and that part of the qualification throat relative section of each hole and body half one intersects, and each hole tilts with respect to the axis of throat.

Guidance can comprise to be inserted, and inserting can embed in each hole, a hole that has a raw material thread to pass in each is inserted, and an inclined end face, the shape of this inclined end face and the shape complementarity of throat are arranged.

Perhaps, each hole can intersect at localization cavity, and inserting to be housed within the localization cavity; Make it against the raw material thread that passes each hole.

Inserting to have polygonal cross-section, and limits and to have the plane that in use is used for the location structure that engages with raw material thread respectively.

Insert and to constitute by copper or copper/tungsten.

Body half one preferably conducts electricity, and a terminal or contact is arranged to be connected in power supply in each body half one.

Body half one preferably is installed on the non-conductive head, and this head is with state fixed body half one spaced apart.

Description of drawings

Fig. 1 is the exploded view according to spraying plating head first embodiment of thermal spraying equipment of the present invention;

Fig. 2 is the stereogram of the equipment of Fig. 1;

Fig. 3 is the rear end view of the equipment of Fig. 1;

Fig. 4 is the cutaway view along 4-4 line among Fig. 3;

Fig. 5 is the partial exploded view of second embodiment of the spraying plating head of equipment;

Fig. 6 is the cutaway view of second embodiment of spraying plating head.

The specific embodiment

Equipment shown in Fig. 1 to 4 comprises a thermal spray head, and this head in use is connected in compressed air or source nitrogen by flexible pipe 10, and is connected in a high current power supply 12.

The General Principle of equipment work is similar to the principle of No. 98/00574, aforementioned international patent application WO substantially, and the content of this international patent application is used for referencial use in this manual.

The spraying plating head of equipment comprises first and second bodies, half one 14 and 16 of conduction, and they are machined to aluminium alloy, is installed on the non-conductive head 18, and this head for example can with suitable plastics such as PTFE be molded or machined is made.

Shown in the exploded view of Fig. 1, body half one 14 and 16 is articulated in head 18 by pin, and this helps the assembling of head and the respect to one another correct location of body half one.The outer sleeve 56 of toughened plastic such as nylon is fixing on the throne with body half one, and is located reliably by a pin 58.

The front surface of head has a circular middle body 20, is the outlet 22 of a nozzle at the center of this part, and this nozzle has an import 24, and has a cylindrical shape throat of extending between import and outlet.This throat is taper from import to outlet, thereby has the inlet diameter of 8mm and the outlet diameter of 8.5mm.

Cavity

28 and 30 respectively in body half one 14 and 16 machined form, and limit inclined hole 32 and 34 respectively, described inclined hole becomes the about 30 ° angle and the

slot part

36 and 38 of body half one that limits throat 26 to intersect with the axis X-X with respect to throat respectively, thereby the angle between two holes is 60 °.

Copper is inserted and 40 can be arranged in each hole, inserts 40 to have end 42, and the shape of this end and the

groove face

36 and 38 complementations that limit nozzle throat, thereby when inserting in hole 34 when in place its end 42 and throat's flush.Form a hole 44 in each is inserted, raw metal silk 46 of the size receivability in this hole is inserted when described silk passes, and can electrically contact with described silk when entering throat 26.

In the model machine of equipment, raw material thread 46 points to the crosspoint that overlaps with outlet 22 and the central axis X-X of throat substantially on the outer end of throat 26.In some application scenario, perhaps need move this crosspoint, but it has been found in practice that this crosspoint is preferably in the throat in the throat outside.

On body half one 14 and 16, be respectively equipped with

electric connection

48 and 50, so that connect high-

power lead

52 and 54, described lead is connected in power supply 12 with body half one, thereby makes electric current reach raw material thread 46 by body half one with inserting, and causes electric arc in the crosspoint of raw material thread in throat.In the model machine of present device, power supply 12 is the constant voltage sources with about 42 to 48 volts (and being about 32 to 36 volts in the situation of legacy equipment) work.Arc current is between 150 amperes and 300 amperes, and 2 to 5 crust (g) at the gas pressure at import 2 places are generally 4 crust.

Second embodiment of Fig. 5 and 6 expressions thermal spray head of the present invention.Second embodiment is similar to first embodiment to a great extent, thereby only draw body half one 114 of a conduction of Fig. 5, and it is corresponding to body half one 14 of Fig. 1.The body half 116 (see figure 6)s coupling of body half one 114 and a complementation, this two and half one is assembled into a non-conductive body according to the mode identical with first embodiment.

The main distinction between first and second embodiment is, in the situation of second embodiment, each body half one limits a rectangular channel or cavity 118, so that admit the contact end of detachable 120 forms of inserting, a diameter to extend from the upright head part 126 of body half one 114 greater than the less relatively hole 122 of raw material thread 124 diameters, directly over the bottom of cavity 118, leave the bottom of head part 126, and further pass the end 128 of body half one, shown in the cutaway view of Fig. 6.Be machined to a central groove 134 on 120 in its four adjacently situated surfaces each of inserting, thereby in fact described groove extends around the body of inserting.The function of inserting will describe in detail hereinafter.As in first embodiment, the aligning of the hole 122 and the central groove 134 in 120 of inserting makes raw material thread 124 intersect at a point, and the end 130 of the throat 132 that this point is just limited two body half ones is with interior or just exceed this end.

The passage that the square/rectangular cross section of one taper is arranged in the throat 132 of this embodiment, rather than circular hole, this is because easier like this processing.And the circular hole of outlet is not necessary.The import of throat is 6mm * 6mm, exports into 6mm * 7mm (rectangle).

Insert and 120 serve and the copper of first embodiment, the 40 identical purposes of inserting, generally constitute by copper or copper/tungsten.A through hole 136 passes to sidepiece from sidepiece to be inserted.In model machine, insert on the direction of through hole 136, about 20mm that inserts is long, and its each surperficial 12mm is square, and 134 about 1mm are dark for groove.Be provided with indenture 138 on each surface on the central groove either side, it is as the locator of place kick or flat head screw, as illustrated in Figures 5 and 6.

As mentioned above, raw material thread 124 in use is positioned at groove 134 (see figure 6)s, and inserting provides the power that makes raw material thread point to its crosspoint, thus make raw material thread and insert between form good electrical contact.

Above-mentioned inserting has insert many advantages of 40 of the tubulose that surpasses first embodiment.At first, each is inserted and has four wear surfaces, thereby only need turn over 90 ° a new wear surface just can be provided.The life-span of inserting in other words, is longer relatively.Have been found that this inserting do not resemble such easy obstruction in the situation of inserting of boring.This inserting made the spray torch head of also packing into from the front easily easily.

As described above described in the international patent application, delivering to the gas pressure of nozzle interior and volume preferably regulates to such an extent that caused air-flow (sonic orchoked gas flow) sound or that block before producing electric arc in throat, thereby the generation of electric arc has in the discharge end portion of nozzle or just exceeds the effect that discharge end portion produces hypersonic flow in throat, otherwise can't reach this effect.Formed high flow rate causes the very thin atomizing of fused raw material particle, and at described particle very high particle speed during from the substrate of nozzle directive.

Have been found that and use velocity of sound or supersonic airstream, and electric arc is positioned in the zone of supersonic speed or velocity of sound air-flow, can obtain the most effective effect.

Because the very high-temperature (being generally 4000 ℃) of electric arc, electric arc heating rapidly enter the gas of electric arc and make its remarkable expansion.This rapid expansion as the source of the gas in the flow field, is blocked the air-flow by electric arc effectively effectively.Because this ponding, gas are tended to flow around " obstacle ", be similar to water flowing around the concrete bridge post.

When having supersonic airstream, the gas that flows to " obstacle " (electric arc) " is not known " electric arc, until its actual electric arc that enters, thereby makes gas be forced into arc region.The high flow situation of the high pressure of Xing Chenging causes dissolving the very thin atomizing of raw material like this.Therefore, in using the situation of ultrasonic basic flow, electric arc can be positioned at any position along throat, until and comprise the exit region of throat and just exceed described exit region.In the situation of supersonic speed ejection, discharge currents has the supersonic flow field structure of rhombus.

Raw material thread 46 can be traditional solid filament, still, has been found that the belt carcass silk that uses the metal ceramic powder that comprises the tubular metal body and include, and uses nitrogen or other suitable inert gas, can obtain fabulous effect like this.Cermet material generally is the metal of sintering and the mixture of carbide, because the hard carbide material is included in the metal adhesive, thereby tends to improve carbonaceous deposits from thermal spraying method.Use pure nitrogen gas or other suitable inert gas can protect the raw metal particle of atomizing, make it avoid oxidation, thereby significantly improve the quality of the coating that is produced.

Have been found that and adopt spraying plating distance short between jet expansion and the substrate to be plated, preferably less than 10mm up to little to 5mm, can further reduce the formation that the coating quality is had the oxide of adverse effect like this.In one type of prior art syringe, short jet length can cause substrate overheated, and still, owing to the very high gas flow by coating apparatus of the present invention, this gas sprays and has cooling effect, and it is overheated to prevent.

It is believed that, compare with traditional about 30 ° angle of the crossing, adopt at least 45 °, be generally 60 ° the relatively large raw material thread angle of the crossing, can guarantee, the end that produces the some raw material thread at electric arc is more stable in the high velocity air in throat, makes the atomizing of the motlten metal that electric arc produces more even because of the less exposed surface cross section of raw material thread.Relevant therewith, raw material thread guidance structure is not charged in the throat, thereby the air-flow in the not disturbance throat, and this also is important.

Claims

1. A thermal spraying apparatus comprising a nozzle defining a throat with an inlet and an outlet, and a gas flow path aligned with the axis of the throat so that the gas under pressure can be sent to an inlet; at least first and second guides arranged to respectively guide the feed filaments through the inlets towards an intersection within or adjacent to the throat end; a power supply arranged to be connected to the feed filaments so that between the wires causing an arc in the throat; and a source of compressed air arranged to supply air to the throat, said guides being arranged so that the raw wires point towards the intersection, thereby defining a 45° and 90° between the raw wires angle between.

2. The thermal spraying apparatus of claim 1, wherein the guides are arranged such that the angle defined between the filaments is approximately 60°.

3. Thermal spraying apparatus as claimed in claim 1 or claim 2, wherein the nozzle is formed from first and second body halves, each body half defining a portion of the throat.

4. The thermal spraying apparatus of claim 3, wherein said guides respectively include holes formed in the body halves, each hole intersecting that portion of the body halves defining the relevant portion of the throat , each hole is inclined relative to the axis of the throat.

5. The thermal spraying apparatus of claim 4, wherein said guide includes inserts receivable in relevant holes, each insert having a hole through which a raw material wire can pass, and having a An end face whose shape is complementary to that of the throat.

6. The thermal spraying equipment according to claim 4, characterized in that: the holes of the guides respectively intersect with the positioning cavities, and the inserts can be received in the positioning cavities, so that the inserts abut against and pass through Raw material with holes.

7. The thermal spraying apparatus of claim 6, wherein the insert is of polygonal cross-section and defines planes, each plane having a locating structure for engaging the feedstock wire in use.

8. The thermal spraying apparatus of claim 7, wherein said insert is of square cross-section and defines a rectangular plan with slots formed in at least one of the planar faces to engage the feedstock wire in use .

9. The thermal spraying device according to claims 5 to 8, characterized in that the insert is made of copper or copper/tungsten.

10. Thermal spraying apparatus as claimed in any one of claims 3 to 9, wherein said body halves are preferably electrically conductive, with a joint or contact on each body half, so that Connect to power supply.

11. The thermal spraying apparatus of claim 10, wherein said body halves are mounted on a non-conductive head, said non-conductive head holding said body halves in a spaced apart state. department.

12. Thermal spraying apparatus as claimed in any one of the preceding claims, wherein the throat is rectangular in cross-section.