DE1085744B - Annealing furnace system for the production of hard material coatings by gas plating - Google Patents

Description

GERMAN

It is known to use annealing furnace systems for gas plating by nitriding or cementing are provided with a reaction vessel with a cooled head part and a supply pipe which is connected to the headboard. In this system, the reaction gas is through the feed pipe into the Reaction container in which the workpieces to be coated are located. The gas reacts then on the workpieces to be coated.

The invention relates to an annealing furnace system for producing hard material coatings, in which, in contrast to the known systems, several reaction ^{gases are fed to a reaction zone 1} in which the workpieces to be coated are located. The device according to the invention also consists of an annealing furnace into which one or more reaction containers can only be lowered over part of their length, the reaction containers being provided with a cooled head part. The annealing furnace system according to the invention also has an insert tube which is attached to the head part and which contains holding devices for the workpieces to be coated. Several feed lines for the reaction gases protrude into the reaction zone of the insert tube. The insert tube, which contains the supply lines, can be extended and retracted with the head part. The device is used in particular to convert metal halides for the production of, for example, the known coatings, the nitrides, carbides, borides or suicides of titanium, zirconium, chromium, etc. If the device according to the invention is built in the manner shown in the figures, for example namely that the gases are conducted downwards into the reaction zone (downdraft), then their use leads to more uniform coatings than if the gases, as in the known devices, are fed to the reaction zone from below or in a horizontal pipe.

In the device according to the invention, a reaction vessel described in more detail below is shown in a conventional electrically heated annealing furnace can be raised and lowered and from the lines of the cooling water. and the reaction gases arranged easily detachable, within the annealing furnace for heating and implementation of the introduced metal halides, taken out in a glowing state, so that in its place Immediately another reaction container can be used again in the annealing furnace and at one of the Annealing furnace spatially distant place, brought to the cooling, with several such annealing furnace to one Battery combined and the reaction containers or crucibles belonging to each individual annealing furnace in one common cooling system can be cooled, opened and recharged.

Annealing furnace system

for the production of hard material coatings
by gas plating

Applicant:

Metallgesellges ehaft Aktiengesellschaft,
Frankfurt / M., Reuterweg 14

Willy Ruppert, Frankfurt / M.,
Gottfried Schwedler, Offenbach / M.,

Otto Essewein, Frankfurt / M.,

and Bernhard Fritz, Frahkfurt / M.-Hedderriheini,

have been named as inventors

The suitably mobile, electrically heated annealing furnace with the reaction container arranged in it is designed according to the invention so that the reaction container with its end open on one side Piece protrudes from the annealing furnace and this end as a water-cooled head with support bolts, claws or the like. For lifting the container by means of a crane or the like. Is provided. The support of the The reaction container in or on the annealing furnace is carried out by arranging support chairs and support claws or the like on the ceiling of the furnace, which is insulated against thermal radiation.

Further details in the design and arrangement of the reaction vessel according to the invention and the operation of the same by means of a transport crane are shown on the basis of the drawings of the closer, without thereby limiting the general inventive concept to this embodiment should be.

Figs. 1 and 2 show in front and side views the overall structure of the annealing furnace with reaction vessels together with feeds and feed lines;

Fig. 3, 4, 5 and 6 show a view of the reaction vessel and the pipes detachably arranged in it and lines for the supply and discharge of the cooling water and the reaction gases with a container to accommodate the batches that are to be provided with a hard material coating.

Fig. 7 and 8 show a side view of a transport crane suitable for operating the reaction crucible.

009 567/196

3 4

In all figures, 1 is the reaction become. For the separation of hard materials, the container or crucible is designated, which is only opened at one end from the cooled head of the reaction container 1 (upper) and made of quartz or a protruding insert tube 10 at an upper end of highly heat-resistant chrome-nickel steel with pre- provided with a flange 11, on which the preferably more nickel than chromium or from a 5 flange 12 with the supply pipes 13 and 14 and highly heat-resistant chromium-nickel alloy, optionally also 17 and corresponding shut-offs. In the case of steels, a higher nickel content should be aimed for in these lines 14 and 16 and 17 a in order to prevent the formation of the brittle σ phase in the (Fig. 3). These supply pipes serve to avoid the steel in the area of the annealing crucible, the supply of the selected metal halides, ζ. Β. during annealing at temperatures between 600 and 10 Ti Cl ₄ , in a hydrogen atmosphere, such as from 900 ° C. Such steels are known and can be seen in Fig. 1, and the supply of a volatile one is commercially available. Of course, it is not necessary to combine the metalloid that forms the cooled parts of the reaction container with the metal, e.g. the carbon tar and the lines are also made of highly heat-resistant material for the carbides in the form of volatile carbon steels. For these parts, simple 15 hydrogen supplied to the reaction chamber is sufficient. The structural steels. The use of corrosion-resistant hydrocarbons, e.g. B. methane, here are gen steels for these parts, however, in terms of preferably with hydrogen diluted so far that on their resistance to corrosive liquids from these hydrocarbon-hydrogen and acidic gases the advantage of longer life mixture at reaction temperatures of 900 to and less maintenance. 20 1200 ° C no free carbon, e.g. B. Soot, deposit

According to the illustration of Fig. 3 is around the upper can.

At the end of the quartz crucible 1 a clamp 2 with tensioning As shown in Fig. 6, the ends of the range

screws 3 and connecting straps 4 arranged, halide (13 ')> and hydrocarbon gas supply

around the water-cooled head, which advantageously consists of tube (15) up to or into the reaction zone 10 b, so

the two parts 5 and 7 with the flanges 6 and 8 25 that the reaction gases only in this reaction zone

exists on the quartz tube 1 with the help of pressing after heating by the countercurrent outside

seals or synthetic resin-like masses gas-tight of the insert tube 10 for rising exhaust gases

to fix. The reaction marked 5 a and 7 a succeed. The narrower part of the interchangeable

Nozzles for the cooling water are shown in Fig. 2 lower part 10 a of the insert tube 10 can

borrowed. The cooling water is added at 5 a, over which as 30 also with advantage to generate one or even

Water flow indicator developed connection 5 b exploited several volatile reaction components

in 7 and derived via the nozzle 7 a . They will. You fill the room for this purpose

Lead 5α and lead Ta are preferably between the narrower part of the interchangeable piece of the

shut off by taps. Insert pipe and the gas lines 13 and 15 as well

To the reaction vessel 1 with its water 35 the thermocouple shell 12 a with suitable cooled head 5, 7 in the illustrated in Fig In this the heating jacket 24 and the electrical resistance area of the reaction vessel adjusting temperature heater 25 to be able to be raised and lowered, to deliver at least one reaction component, support bolts 9 or the like are arranged on the head part 5, 4 ° To promote the generation of volatile Reactdie on the support chair 22, which on the furnace ceiling tion components can sit or in some other way supported by the flange 12 ending supply pipe 17 with which is attached just below the can be. The upper head part 7 also has valve 17 a, a suitable gas can be introduced, two support bolts 7 b, which are preferably arranged parallel to the, for example, made of titanium or TiC by support bolts 9. With the help of the 45 introduction of hydrogen chloride through 17 volatile bolts 7 δ, the upper head part can be produced from the reaction titanium chloride and the actual reaction crucible 1 can be fed in with the crane to be described in 10 b.

be lifted. The upper part 7 of the reaction container from Fig. 1 and 2 on the foot part of the mobile

ters 1 also has two line stubs 18 with stops and strips 30 arranged in the annealing furnace 23

Valve 18 α and the vacuum manometer 19 for an 50 serve for easy and quick adjustment of the in

show the negative and positive pressure in the reaction vessel in the transport crane shown in Figs. 7 and 8

and 20 with the shut-off valve 21 for diverting its start-up to the annealing furnace in order to

To use or to lift out reaction gases after the reaction or Zer- container 1, if they

Settlement of the metal halides in the reaction zone from or to the still to be described cooling or

be brought inside the reaction vessel 1 via the exhaust gas storage device,

control 20 α. The specially designed for the present purposes

To this in the lower part of the container 1 arigeord- wound transport crane (Fig. 7 and 8) consists of

Neten and preferably widened reaction zone parts which can be displaced telescopically relative to one another

10 b (Fig. 5) leads a concentrically in the reaction or columns 31 and 35, with protective shields against the

container 1 arranged insert tube 10 (Fig. 5), the 60 heat radiation in the same telescopic design, the

preferably via a flange connection a jointly on the mobile carriage 32 with the as

has removable part 10a and acting on its Um- counterweight nitrogen tank 33 and

Fang radiation protection plates 10 c are arranged to one of the backrest 34 are arranged. Through the handle

Heat radiation upwards against the water 39 via the wheel 38 with the pinion and a ratchet

to shield a chilled head. The extended ⁶ 5 of the brake 37 is raised and the rack 35

Part 10 b of the insert tube 10 forms the actual lowered and thus the support arms 40 attached to it

Treatment room for the deposition of hard materials or 40 a, whose function from Fig. 7 without further ado

from the gas phase and can be seen during the deposition of this.

Fabrics in the form of covers in shape and size In addition to the manual drive, other drive

adapted to the respective workpieces 7 ° types possible, z. B. with the help of a small elec-

5 6

Irish engine. The drive by means of compressed air is particularly simple and advantageous, preferably made of rubber or acid-resistant. For this purpose, if plastics are made, the valves 14 and 16, the tube 31 closed at the bottom, are shut off as smoothly as possible, and the valves 18 α and 20 are opened. Over and flawlessly round inner surface, during the tele- the valve 20, the air is pumped out of the reaction head-like extendable column 35 at least at its 5 container, then the lower end of the reaction is filled as smoothly and well as possible into the container with purified hydrogen, nor-tube 31 suitable or sealed upper maize is pumped out and filled with hydrogen again. The vacuum manometer 19 is checked from a compressed air bomb that is still on the crane next to the pumping out and filling with hydrogen is to be attached via a nitrogen bomb. After the last filling with hydrogen for lifting the support arm into the lowest part of io, the pipe 31 is also closed with compressed air and, when lowering, valve 21.

drained again. Now you pivot the support arm of the transport - the support arm 40 can, as can be seen in Fig. 7, crane in position 40 and lifts with the aid of the crane, can be releasably pivoted or exchanged, not only the reaction container on the bolt 9 from the Abdaß the container 1 to the support bolts 9, 15 adjusting device and moves the reaction container but also the upper head part 7 with insert tube 10 with adjustment of the crane with the help of the stops on the support bolt 7 b transported, in particular to the annealing furnace and by lowering the special also the insert tube 10 from the reaction column 35 into the preheated annealing furnace,
container 1 removed or swiveled in. After a few minutes you can see the va. The receiving gifts 40 b of the support arm 20 kuummanometer 19 a pressure increase inside 40 is at 40 c about its own axis with play for the purpose of the reactor vessel as a result of the heating. Now rotatable for better adjustability. the water and gas connections are made, whereby the cooling and shut-off device (Fig. 9 with a plan view Fig. 10 before connecting the gas lines) consists of a support column 41 with part of the overpressure via the valves 14, 16, 21 a rotatable attachment 42, which drains with the aid of 25, whereby the air is flushed out of these in the lock 43 in each case for putting down or down. It is recommended that the container 1 can be stopped with the aid of the reaction crucible in question, the most favorable ring overpressure when moving in or out. To hold in the arms 42 α from the annealing furnace.

of the rotatable attachment 42 are receiving grooves 42 b. The lower part of the reaction for receiving the support bolts 9 and 7 b of the reactor 30 with the expanded part of the insert tube 1 and the upper head part 7 is now heated and the reaction material on the Reaction temperature, left. A particularly favorable arrangement option- Here, purified hydrogen or a mixture of hydrogen and volatile matter purified from the reaction vessel on the rotatable attachment is shown. in which large air contains hydrocarbons, as their equilibrium flaps 45 are let in with springs which correspond to the connection with hydrogen and solid carbon in the bonds between the upper space 46 a and lower temperatures for the TiC coatings, lower space 46 b close automatically. The control through valve 15 in the reaction vessel and the Abeines with the help of the strong fan 49 generated gas through the valve 21, the nozzle 20 and the exhaust air flow to cool the shut-off React 40 gas control 20 a in the exhaust line. Now the tion crucible can be closed with the help of levers 47 and 48 via valve 18 α. The heating times of the concentric shafts 47a and 48a and eccentric not only depend on the size of the reaction container disks 50 and the batches, but also on the crucible. A similar arrangement can also be used, material. In order to heat up Reak, if the reaction crucibles made of high-heat-resistant quartz crucibles are cooled under the same conditions, digem steel after the reaction in water. longer times than for heating up the reaction. The intermediate floor 44 with the air crucibles is made of heat-resistant steels. After reaching 45 and their actuating devices, due to the reaction temperature of, for example, 950 to a simple, stable framework to support the 1000 ° C, the crucible contents are held for about V2 to support column 41, the fan is driven by a liquid 50 for 1 hour under flowing hydrogen or Replaced the circulation device and the container 46 closed the bottom plate 51 by the specified hydrogen-hydrocarbon mixture. _{Ti Cl 4 can} then only be switched into and then switched via the valve 14 and the container 46 can then also be admitted to the water supply and discharge supports 13 and, if necessary, the lines that are passed through. pure hydrogen adds the volatile hydrocarbons required for separating the car-die mode of operation of the annealing furnace system after the erbids. The invention is now designed, for example, in the manufacture of the carbide deposition.The constellation of titanium carbide layers is also selected for the carbide deposition as follows: Concentration of the hydrocarbons in relation to the charge is carried out with the aid of the transport the head part 7 is not able to deposit soot, ie carbon, with the insert tube 10 from the reaction ^{vessel 16o} . The supply of the titanium tetrachloride can be withdrawn and the extended part of the insert can take place, for example, with the aid of the devices labeled 27, 28 tube 10b with the reaction material, for example drawing and 29 in FIGS. Through nozzles, press dies, fed from below. The work introduction of hydrogen into the immersion tube 28 and testify with a bolt or a bayonet through the closure located in the evaporation flask 27 or a similar device in the ⁶ 5 titanium tetrachloride a hydrogen-titanium tetra-widened part of the insert tube is held. After the chloride mixture has been generated and the charging process via 13, the insert pipe 7 is fed into the reactor pipe 10. The concentration of the titanium tetration tank 1 is retracted with the aid of the crane. After closing the flanges 6 and 8 with the aid of the flow rate of the hydrogen and completely ring-shaped seals (not shown), the 7 ° particularly well by setting the temperature of the

Titanium tetrachloride can be regulated with the thermostat 29. The concentration of titanium tetrachloride vapor is adjusted according to the equivalent amount of hydrocarbon supplied, e.g. B. Methane.

The flow velocities and the; Amounts of gas can easily be adjusted so that the specified workpieces are provided with the desired coatings on their surfaces in the available reaction times of about 3 to 5 hours. After the Ti C deposition has ended, the supply of the Ti Cl ₄ -hydrogen mixture is switched off and the system is then flushed through with pure hydrogen or with the hydrogen-hydrocarbon mixture described ^{for about x} hours. Thereafter, valves 14, 16 and 21 are closed, valve 18 a is opened, water connections 5 a and Ta are disconnected and the reaction container is moved out of the annealing plant using the transport crane described and placed on the cooling or storage device described. After the reaction container has been moved out of the annealing plant, the mean temperature rises in the entire crucible despite the cooling of the lower part of the annealing crucible, so that an increase in pressure is initially observed on the vacuum manometer (for reaction crucibles made of quartz for about 10 to 20 minutes). In the further course of cooling, the overpressure disappears and a negative pressure develops, which can be read on the vacuum manometer when the valves are closed. The formation of negative pressure brings with it the risk that air may be sucked into the reaction vessel via leaks - which may have occurred during the deposition of the coatings - and the hydrogen located there could explode. In order to avoid this, one switches over the movable nitrogen line 33 α, which is guided with guides 33 b on the transport crane, nitrogen at such a pressure via the valve 21 on the reaction vessel that it is somewhat under the pressure that, experience has shown, when the First sets the crucible, lies. This precautionary measure is sufficient to avoid under all circumstances the formation of negative pressure in the reaction crucible while the reaction crucible, which is at 900 to 1000 ° C., is driven to the cooling device. At the cooling device, the connection to a hydrogen supply and exhaust gas line is made (and to the water supply and drainage for further cooling of the flanges) and the crucible is now allowed to cool there under flowing hydrogen.

The cooling speeds can be forced very easily by using _; the powerful fan 49 acting as an air blower blows fresh air running from the lower part of the cooling device or from a compressed air line against the still hot reaction container. The air flow can be regulated with the aid of the air flaps 45. This type of cooling is well suited for cooling the reaction crucibles made of quartz and also of stainless steel.

In the case of reaction vessels made of stainless steel, however, even higher cooling rates can be achieved, if the sheet metal container of the - as described - · modified cooling device with Water fills and the crucible is quenched by moving it into the cooling water, with the aid of a circulation pump (instead of the fan) then ensures that the water is thoroughly mixed and prevents the formation of larger vapor bubbles that impede rapid cooling. Just this last measure has the great advantage that it is one for a large number of air-hardening steels supplies sufficiently high cooling rate in the reaction vessel, so that these steels After the Ti C coatings have been applied, the prepared tools fully cure and thus the deposition the protective coatings on the tools with the hardening of the tool steel used as the base material can be combined without any special outlay on equipment.

With the aid of annealing and cooling system and a reaction vessel made of quartz according to the invention can also be the pre-degassing of the base material in a vacuum under 1 mm Hg, especially at 10- ² to 10- * mm Hg measured at 600 to 700 ° C and preferably Easy to carry out up to 1000 ° C (see patent application M 27211 VIa / 48 b of May 25, 1955 = German Auslegeschrift 1 056 450). In this case, getter metals can be used in the reaction vessel with the workpieces to be degassed to generate and increase the vacuum.

The use of the known membrane valves has been shown to be a particularly favorable design for the valves 14, 16, 17 a, 18 α and 21 located on the head part of the reaction vessel.

Claims (2)

Patent claims: 1. Annealing furnace system for the production of hard material coatings by gas plating with one or more reaction vessels which can be lowered only to part of their length into an annealing furnace with a cooled head part and an associated supply pipe, characterized in that an insert tube (10, 10 a , IQb) is attached, which is provided with holding devices for the workpieces to be coated and contains feed lines (13, 14) for the reaction gases, which. Reach down into the reaction zone (105) of the insert pipe, the insert pipe containing the feed lines being retractable and extendable with the head part. 2. Use of an annealing furnace system according to claim 1 for vacuum pretreatment and / or for the subsequent heat treatment of the base material after the production of the coatings. Considered publications:
British Patent No. 589,977;
French patent specification No. 1 093 772. In addition 3 sheets of drawings © 009 567/196 7.60