EP0785402A1 - Heat treatment installation for metallic article loads - Google Patents

Abstract

An installation for the heat treatment of a charge of metal components comprises: (a) a first assembly (1) of elements (2 - 7, 9) arranged in an upper line, at least two of these elements being furnaces open at the bottom; (b) some elements (3 - 7, 9) able to move on lateral tracks (27A - 27F) with respect to the longitudinal axis of the upper line, allowing the sliding of these elements of the first assembly from a working position to a transfer position and back, the working position for each moving furnace (3 - 7) incorporating a hoist (30) acting on a stopper on the furnace; (c) a second assembly (11) of elements (12 - 14) of which at least one is a quenching vat, these elements fitted with hoists (34) being able to move on an horizontal track (15) and arranged in a lower position under the transfer position of the first assembly, and allowing, for any number of the elements of the two assemblies, the bringing together of each element of the second assembly (11) with respect to each chosen element of the first assembly (1); and (d) a manipulator (17) for charging and discharging, moving on a vertical track (16) extending the length of the first assembly (1) and allowing the charging and discharging of all the elements of the first assembly (1).

Description

The need for different branches of industry to use more and more parts produced in series is increasing and also the use of different heat treatments as well as alloys or other special materials forming said parts. The need has therefore increased to use installations allowing various heat treatments to be carried out and comprising several elements, such as ovens or quenching tanks, while allowing easy access so as to be able, on the one hand, to arrange the facilities in a rational way and, on the other hand, allow the automation of treatment processes.

An installation making it possible to carry out heat treatments on loads of metal parts with a rational arrangement of the essential elements is described in European patent no. 0 296 102 where the two sets are arranged one under the other and where each element of the second set of the lower line can be brought opposite each element of the first set on the upper line.

Also known is the European patent application no. 0 533 615, by the same applicant, describing an installation for the heat treatment of successive loads comprising an oven with a vertical arrangement open downwards, this oven being capable of sliding in a sliding plane placed at the height of the oven between a position located above a rack elevator and a position above a bin. This patent application only describes an oven arranged above a quenching tank. This sliding oven has the advantage of being able to push the load from a position under the oven to a position above a tray without the need to hang or unhook the load in or from the oven.

Market conditions obliging the industry, on the one hand, to increase the quality of their products or their processes and, on the other hand, to lower prices, an object of the present invention is to provide an installation even more flexible than that indicated in the first place, while maintaining the superior quality made possible with the second installation mentioned above. This object is achieved by the installation described in the independent claim.

La figure 1

est une vue en élévation longitudinale schématique de l'installation selon l'invention,

la figure 2

est une vue en plan de dessus schématique de l'installation de la figure 1,

la figure 3

est une coupe à plus grande échelle selon la ligne III-III de la figure 2,

la figure 4

est une coupe à plus grande échelle selon la ligne IV-IV de la figure 2,

la figure 5

est une coupe en agrandie selon la ligne V-V de la figure 2,

la figure 6

est une coupe à plus grande échelle selon la ligne VI-VI de la figure 2,

la figure 7

est une vue en plan de dessus du manipulateur et

la figure 8

est une vue en plan de dessus du chariot d'une station à laver.

The invention will be explained in detail with reference to the accompanying drawings showing by way of example an embodiment of the object of the invention.

Figure 1

is a schematic longitudinal elevation view of the installation according to the invention,

figure 2

is a schematic top plan view of the installation of FIG. 1,

figure 3

is a section on a larger scale along line III-III of FIG. 2,

figure 4

is a section on a larger scale along line IV-IV of FIG. 2,

figure 5

is an enlarged section along line VV in FIG. 2,

figure 6

is a section on a larger scale along the line VI-VI of FIG. 2,

figure 7

is a top plan view of the manipulator and

figure 8

is a top plan view of the cart of a washing station.

Figures 1 and 2 schematically show a relatively complex installation to be able to demonstrate different applications and possibilities for handling various loads in heat treatment. It is understood and will emerge from this description that Figures 1 and 2 show only some of the many possibilities of an installation according to the invention and that the user is able to modify this installation to a large extent for the adapt to their needs. In other words, thanks to the installation according to the invention, the user can, from a very wide range of combinations and possibilities, choose and define the optimal installation that best meets said needs.

Figures 1 and 2 show, in analogy to an installation according to European patent no. 296 102, a first assembly 1 on the upper line comprising a group of ovens 2-7 and at one end a washing station 9. This installation was initially planned with a symmetrical arrangement with respect to the oven 5, but for For reasons of presentation, the second oven similar to oven 2 and the second washing station similar to station 9 have not been shown.

In the example according to FIGS. 1 and 2, the furnace 2 is an income furnace described in more detail with the aid of FIG. 5, this furnace being vertically movable by means of a bracket and a mechanical drive. . The austenitization, carburizing or carbonitriding furnaces are described in more detail in Figure 3.

Ovens 3 and 7 are the same as ovens 4, 5 or 6 with the difference that low temperature heating is integrated in their heating chamber. The washing machine 9 is explained in more detail in FIGS. 6 and 8. All the elements of the first set, except for the vertically movable oven, can move laterally with respect to the longitudinal axis of the two sets, as is see in Figure 2.

The second assembly 11, see FIG. 3, is arranged on the lower line and comprises, in this exemplary embodiment, three treatment stations, 12, 13 and 14. The station 12 is an oil cooling tank, the station 13 is a salt cooling tank and the station 14 is a water cooling tank. The processing stations 12, 13 and 14 are arranged on a horizontal track 15 constituted by two rails, in a similar manner to that which is described in European patent no. 296 102. The treatment tanks, here cooling, are freely movable on this horizontal way to be able to come next to any oven.

It is obvious that in a given installation, the tanks are arranged in such a way that the path traveled by these tanks is minimum. This means that, in a specific installation designed for one or more specific work sequences, it is not necessary for each tank to come opposite each oven but of course only opposite the planned oven (s) ( s) for the treatments envisaged.

The loads are loaded and unloaded using a manipulator 17 mounted on a longitudinal track 16 consisting of two rails whose plane is perpendicular to that formed by the tracks 15. This manipulator, to which we will return in more detail to l 'support of Figures 3 and 7, can move along the installation to load or unload any element of the first set, after having taken the load to be treated on the storage stations before treatment 18 to deposit it, after the desired treatment, on the treatment stations storage after treatment 19. This is indicated symbolically by the arrows M.

Figure 3 shows a section along line III-III of Figure 2 with, in the upper line, the oven 5 and, in the lower line, the tray 13 of the assembly 11 and the manipulator 17. The oven 5 is similar oven disclosed and described in detail in European patent application no. 533 615, to which explicit reference is made. The furnace 5 is a bell furnace 20 having in its base an opening 21 limited by a belt 22. Heating bodies 23, a turbine 24 and a double jacket 25 ensure the homogeneity of the speeds of the treatment gases in the feed 40 by forced circulation inside and around the bell 20.

The oven 5 is movable from left to right and from right to left in the plane of the drawing in FIG. 3, the position of the oven on the right, above the tank 13, being indicated in dotted lines. The oven stroke is indicated by the arrow CF. For this, it is carried by rollers 26 which roll on a lateral raceway 27D, and is driven by a rack-and-pinion reduction motor 10.

In the position of Figure 3, the oven 5 is closed by means of a plug 28 which is supported by the plate 29 of an elevator 30, guided by a bracket 31 and driven by a reduction motor 32 and rack 32A. The motor control makes it possible to hermetically close the oven 5. This arrangement allows a rapid rise in temperature of the load and has the advantage of ensuring a heat treatment of high precision where the temperature dispersion across the entire load is reduced.

This oven 5 as well as the ovens 4 and 6 allow various treatments such as austenitization, case hardening, accelerated case hardening, carbonitriding, nitriding, annealing and tempering.

By moving the oven 5 to the right in FIG. 3, it is located above the quenching or cooling tank 13, in this case a salt or water cooling tank. When the oven is moved, the rollers 26 roll on the lateral track 27D formed for example by rails. The drive can be rack-and-pinion. This quenching tank 13 is a tank known per se and is rectangular in plan, closed by a cover 33 and containing an elevator 34 consisting of a bracket 35, a support arm 36 and a tray or grid handling 37 (see also Fig. 2). The bracket is equipped with a reduction motor and a rack 38. The cover 33 of the tank is displaceable by means of a displacement mechanism 68 comprising a piston acting on a shaped part, see FIG. 2.

Inside the tank, a fluid guide ring 39 delimits a channel which allows a homogeneous flow of the coolant through the charge 40 by means of a circulating pump or a stirring pump 41. The cover 33 is provided with an opening through which the plate 37 of the elevator 34 can pass.

The manipulator 17, designed to transport the load 40, is attached to the rear of the installation by moving on the loading track 16 comprising an upper support rail 42 and a lower rail 43 on which the rollers roll. 44 of the manipulator. It can therefore reach each element of set 1 of the line upper part of the installation as well as the stations 18, 19. The manipulator comprises a box 45 enclosing an elevator 46 consisting of a bracket 47 equipped with a reducing electric motor and an eccentric 48 acting on a support arm 49.

On the support arm 49 is mounted a lateral transfer plate 50 driven by a reduction and rack motor 51 making it possible to move the load laterally. The travel of this side plate is indicated by an arrow CM. It can be seen in FIG. 7 that one end of this plate 50 is in the form of a semicircle, capable of receiving a base grid 52 of a load 40 made up of loose parts in stacked baskets. This arrangement makes it possible to use only one manipulator for charging and discharging from stations 18 to stations 9-2-3-4-5-6-7-8 and 19 (Fig. 2).

The manipulator makes it possible to deposit a load on the flat sliding surface 8 of the plug 28 placed on the plate 29 brought into the intermediate position. This transfer operation being carried out, it is understood that the manipulator 17 can be evacuated and that the elevator 30 can be driven so as to charge the load 40 by descent and return and at the same time to close the oven by means of the plug 28. The operation of transferring the charge after a heat treatment at high temperature and under controlled atmosphere is similar to that described in European patent application no. 533 615. The elevator 30 of the oven is actuated so as to be placed in an intermediate position between the closed position of the oven visible in FIG. 3 and the lower loading position described above. In this intermediate position, the plug 28 is extracted from the hood of the oven and its flat upper surface 8 is flush with the upper plane of the cover 33 of the container 13.

The oven is then moved from left to right, and the base belt 22 of the oven pushes the base grid 52 on the sliding face 8 of the plug 28 and slides this grid until it reaches the cover 33 The movement of the oven continues until the grid 52 is on the upper face of the plate 37 of the elevator 34 of the tank which has been brought into a position where this upper surface is also flush with the surface. 33. It is therefore sufficient to maneuver the elevator 34 so as to lower the load in the tank, then to load a new load on the plug 28 by means of the manipulator 17 and to return the oven to its initial position and to close it by means of the elevator 30 and the plug 28.

This part of the installation is therefore ready for a new treatment cycle. It turns out that these lateral displacement ovens do not require any hooking of the load and that no moving mechanical part is exposed to heat, which allows the load to be immersed in less than 5 seconds, this permanently under protection carbonated. So no air penetration, and therefore no oxidation, is possible.

The cooling tank 13 with the load after quenching and before draining is moved in front of a washing station, in this case the washing station not shown on the right of FIG. 2, for washing after soaking in the salt of tank 13 As will be described below with the aid of FIG. 8, the quenched charge is extracted from the liquid by the elevator of the tank, then drained and then transferred to the washing station to be discharged by the manipulator 17 which will deposit the load on the storage stations after treatment 19.

In the installation according to FIGS. 1 and 2, the oven 5 of FIG. 3 is similar to the oven 4 and 6 while the oven 3 is shown diagrammatically in FIG. 4, this oven being similar to the oven 7. The oven 3 ( or 7) differs from the oven 5 described above with the aid of FIG. 3 by a low temperature heating 53 integrated in the heating chamber 54. Since this oven is at low temperature, the walls 55 are slightly less thick as those of ovens 4, 5 or 6. The other elements of the bell oven as well as the elevator 30 are the same, just like the motor 56 of the rack drive 57 of the oven 3 (7) on the side track 27B (27F).

FIG. 5 schematically shows another type of oven, namely a preheating oven 2. This oven 2 is movable in height by means of a bracket 58 and a mechanical drive 59. In this embodiment, the plug 60 is fixed and when the oven is in the upper position, the load 40 can be deposited on the plug by the manipulator 17 and then the oven goes back down on the load and the heat treatment cycle starts. The fixed plug is equipped with a gas circulation turbine 61. The manipulator 17 is the same as described above. To unload the oven after the heat treatment, the oven is brought to its upper position and the load can be unloaded by the manipulator.

Figure 6 shows the section on line VI-VI of Figure 2 with in addition the section (in dotted line) of the manipulator and one of the cooling tanks described above using Figure 3. The washing machine 9 comprises two water tanks 66 with two independent water circuits 62 and 63, and above a sealed chamber 64 which can be moved upwards so that the load can be transferred either by means of the manipulator 17 or by means of carriage 65 moving along a track lateral 27A using a reduction motor 67 and rack. This carriage also includes a semicircular plate 65A adapted to push a circular grid 52 supporting the load (Fig. 7).

After the load in the cooling tank 13 has cooled down, the quenched load extracted from the liquid by the elevator 34 in the tank is drained. After draining, the washing station is open in the high position, the handling carriage 65 pushes the load in question in the washing station. After the washing cycle, the manipulator 17 picks up the load for a tempering cycle, possibly in station 2, or else to be deposited on the storage stations after treatment 19.

• pour l'austénitisation-cémentation-carbonitruration sous azote jusqu'à 750° C,
• sous méthanol (+azote) au-dessus de 750° C max. 1'100° C sous gaz ou max. 1'230° C sous gaz,
• carbonitruration avec une adjonction de 3 à 5 % NH₃,
• Dispositif de refroidissement rapide des charges sous atmosphère par une ventilation extérieure au moufle.

To give an example among many other possibilities of handling the various loads in heat treatment, we consider case hardening and quenching. The manipulator 17 takes the load 40 to be treated on the storage stations before treatment 18 and introduces the load into the washing machine 9. After washing, the manipulator unloads the station 9 then goes into the waiting position in front of the work station for the desired cementation treatment, namely one of the ovens 4, 5 or 6. These are ovens with the following possibilities:

• for austenitization-carburization-carbonitriding under nitrogen up to 750 ° C,
• under methanol (+ nitrogen) above 750 ° C max. 1'100 ° C under gas or max. 1'230 ° C under gas,
• carbonitriding with an addition of 3 to 5% NH ₃ ,
• Device for rapid cooling of loads in an atmosphere by ventilation outside the muffle.

• un bac a eau
• un bac à huile, max. 100° C
• un bac à huile, max. 200° C
• un bac à sel, max. 600° C
• un bac de refroidissement sous azote, basse ou haute pression
• ou d'autres bacs connus en soi.

If the station is in the process of processing an old load, it is necessary to wait for the end of the treatment and the discharge of the load by quenching in one of the tanks 12, 13 or 14. As described above, these tanks can be

• a water tank
• one oil tank, max. 100 ° C
• one oil tank, max. 200 ° C
• salt container, max. 600 ° C
• a cooling tank under nitrogen, low or high pressure
• or other tanks known per se.

The oven being moved backwards, the load via the manipulator 17 is deposited on the plug 28 resting on the elevator 30 then immediately lowered to the low position and the oven returns to the working position. The charge is introduced into the furnace for the heat treatment cycle via the elevator 30 of the furnace.

At the end of the cycle, the cooling tank 12, 13 or 14, depending on the operator's choice, is positioned in front of the furnace in question by moving on the horizontal track 15. A new load is waiting on the manipulator 17.

The operator controls the quenching operation, the oven is partially opened and then immediately moved by the reduction motor drive on one of the side tracks 27 C, D or E with the load at temperature and under a gaseous atmosphere on the elevator 34 from the tank and immediately immersed in the coolant where forced circulation of the coolant ensures good homogeneity of the quench. Immediately, the manipulator 17 deposits a new load 40 on the plug 60 of oven 2 which is moved to the high position. The oven then returns to the initial position and the new charge is introduced into the oven and a new heat treatment cycle is restarted.

Then, the cooling tank with the load after quenching before dripping is moved in front of the washing station 9 or in front of the other washing station. Station 9 is intended for washing after quenching in the oil tank and the other station is intended for washing after quenching in the salt tank. The quenched charge is extracted from the liquid by the tank elevator and drained. After draining, the washing station is open in the high position, the handling trolley 65, see FIGS. 6 and 8, pushes the load in question into the washing station. After the washing cycle, the manipulator 17 picks up the washed load for a possible tempering cycle in the furnace 2 or the other similar furnace or else to be deposited on the storage stations after treatment 19.

It emerges from the description that this installation allows, on the one hand, very great flexibility with regard to the various treatments provided and offers the possibility of aligning furnaces with very diverse heat treatment, such as austenitization, carburizing, carbonutriation, nitrocarburization or oxynitriding on the one hand and preheating, annealing and tempering on the other hand, as well as cooling tanks of various types, such as oil, water, salt or gas tanks, as well as washing stations of different designs and this in a single installation allowing rational treatment, thanks to the concept of aligning the two sets, namely the ovens and washing stations on an upper line, and the other elements such as cooling on a lower line, to provide only one manipulator integral with the installation and capable of loading and unloading each oven and each washing station, and by providing ovens which can be moved on a side track, thus making it possible to avoid the costly operation of hanging the load on the oven for a more reliable and faster heat treatment. Such an installation allows automation of certain manipulations only, desired by the user, that is to say partial automation, or total automation.

Claims (4)

Installation for the heat treatment of a load of metal parts, characterized - by a first set (1) of elements (2-7, 9) arranged in an upper line, at least two of these elements being ovens (2-7) open downwards, - in that elements (3-7, 9) of the first set (1) are movable on lateral tracks (27A-27F) relative to the longitudinal axis of the upper line, allowing the sliding of said elements of the first set d a working position in a transfer position, and back, the working positions comprising for each mobile oven (3-7) an elevator (30) acting on a plug (28) of the oven, - By a second set (11) of elements (12-14) at least one of which is a quenching tank, these elements provided with elevators (34) being movable on a horizontal track (15) and arranged in a lower position under said position for transferring movable elements (3-7, 9) from the first set, and allowing, for any number of elements from the two sets, to bring each element from the second set (11) opposite each element chosen from the first set (1), and - By a loading / unloading manipulator (17) movable on a vertical track (16) extending along the first set (1) and making it possible to load / unload all the elements of the first set. Installation according to claim 1, characterized in that the manipulator (17) is guided by an upper support rail (42) and comprises rollers (44) rolling on a lower rail (43) and is provided with an elevator (46 ) acting on a support arm (49) receiving a lateral displacement plate (50). Installation according to claim 1 or 2, characterized in that the washing station (9) is provided with a sealed chamber (64) movable up and horizontally by a carriage (65) rolling on a lateral track (27A). Installation according to one of claims 1 to 3, characterized in that the elevators (30, 34) and the means for lateral displacement of the mobile elements (3-7, 9) are provided with rack-and-pinion reduction motors (32, 32 A , 38; 10; 67).

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