EP1265724A1

EP1265724A1 - High speed oxyacetylene cutting of a thick steel part and device therefor

Info

Publication number: EP1265724A1
Application number: EP01919519A
Authority: EP
Inventors: Guy Prioretti; Véronique Prioretti; Françoise Prioretti-Hacking; Jean-Michel Prioretti
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-03-23
Filing date: 2001-03-15
Publication date: 2002-12-18
Also published as: FR2806654B1; CA2403534A1; WO2001070443A1; US6783605B2; US20030037842A1; AU2001246606A1; FR2806654A1

Abstract

The invention concerns a method and a device for high speed oxyacetylene cutting of thick steel parts. The invention is characterised in that it consists in: synchronously moving a oxyacetylene cutting torch (30) maintained at a predetermined height above the part to be cut (1), and a kerf cutting torch (20) comprising at least a blade-type nozzle (25), which passes inside the very oxyacetylene cut (1.3). The blade-type nozzle (25) emits through its cutting edge at least a heating and/or gas cutting fluid jets striking hard the kerf front combining with the gas cutting fluid jets emitted by the oxyacetylene torch (30) to form a kerf front (1.4) having a broken line profile.

Description

Method for high speed flame cutting of a thick piece of steel, and device for implementing said method

The present invention relates to a method and a device for oxygen cutting steel parts, such as slabs, billets and blooms.

The technological background can be illustrated by document EP-A-0 639 416 which describes a two-line flame-cutting installation, each of which comprises a movable pendulum-type flame-cutting trolley. We can also refer to document US-A-2 820 420 which describes an oxygen cutting torch cantilevered on a horizontally movable carriage, and to document WO-A-96/20818 which describes an overhead crane supporting a telescopically extendable vertical working arm.

In general, conventional flame cutting torches consist of two main parts, a first part of which serves to supply the fluids (oxygen, combustible gas, coolant), which is called the torch body, this part does not not being in direct contact with the flame, and a second nozzle part, which is in turn directly in contact with the flame, and serves to distribute, distribute the fluids, and eject the gases (fuel and combustible) in proportions and specific characteristics, specific to fluid mechanics, to carry out the desired flame cutting operation.

Those skilled in the art know that the oxygen cutting nozzles can simultaneously perform two functions: the first consists in producing a heating flame, by means of the supply and mixing (external or internal to the nozzle) of a gas combustible and an oxidizing gas, such as oxygen, to bring the attack zone of 1 Oxycutting to very high temperature so as to obtain a self-combustion of the metal to be flame-cut thanks to the arrival of a separate oxygen jet. The second function consists in producing and directing a specific oxygen jet over the zone previously brought to self-combustion temperature, in order to obtain the cutting of the metal according to the desired geometrical characteristics. For this purpose, the existing oxygen cutting nozzles comprise one or more cutting oxygen conduits, parallel or not, located in the same plane (generally orthogonal to the attack surface of the product to be cut), and a certain number heating conduits which are arranged either concentrically around the cutting oxygen jet, or on either side of the line of movement of the cutting oxygen jet (s).

The oxygen cutting nozzles used in traditional techniques are positioned at a certain distance from the surface concerned, or attack surface, of the workpiece, the direction of the cutting oxygen jet being generally chosen to be substantially perpendicular to the attack surface for better efficiency (if the cutting oxygen jet is orthogonal to the attack surface, the thickness of material to be cut is minimal, which allows a maximum oxycutting speed with economy of fluids ).

In general, all the oxy-cutting nozzles currently used are mounted to move relative to the piece to be cut, above and / or below said piece, but always outside the groove of oxyfuel. This constitutes a notable drawback, insofar as the cutting oxygen jet must travel a considerable distance in the open air between its exit from the oxygen cutting nozzle and its impact on the surface of the metal to be cut. This disadvantage is naturally all the greater as the thickness of the product to be cut increases, which de facto limits the techniques of oxygen cutting to the cutting of relatively few parts. thick. This drawback is also found for the heating jet, which is generally limited to heating the impact zone on the surface and / or at a shallow depth of the surface of the product. Indeed, it is the heat of self-combustion of the hot metal with the cutting oxygen which generates and propagates the heat along the cutting groove over the entire thickness of the flame-cut product, thus making it possible to maintain and continue. the flame-cutting operation by self-combustion with cutting oxygen. During the cutting process, the jet of oxygen cutting fluids emitted by the oxygen cutting torch maintained at a determined height above the part forms a groove which crosses right through the entire thickness of the part to be cut. The front line of the groove is then substantially rectilinear, and in extension of the axis of the oxygen cutting jet, said line moving progressively during the cutting process, at a speed called oxy-cutting speed, which speed in fact corresponds at the relative speed of movement of the flame cutting torch relative to the workpiece. The oxycutting speed for a nozzle of given geometric and fluidic characteristics is actually a function, among other things, of the thickness of the body to be cut: in fact, the thicker the body, the more the speed of movement is reduced due to the propagation , step by step, and non-instantaneous of the heat of combustion and of the combustion itself throughout the bleeding from the inlet to the outlet.

To complete the state of the art, mention may also be made of various flame cutting processes using several torches.

Document US-A-3,852,126 thus presents an oxycutting process using two torches, including a first torch with a vertical axis, and a second torch with an oblique axis. This provision is intended to allow the lateral bringing together of the two torches in a direction transverse to the trajectory, so that the two grooves partially overlap. It is however not taught to bring the two torches together to the point that their respective grooves overlap completely, and even less to introduce one of the torches in the groove made by the other.

Document EP-A-0 017 807 describes a flame-cutting device having a first cutting torch with a vertical axis, associated with a second deburring torch carried by a support blade passing through the groove, the second torch having only and the sole function of rectifying the edges of the groove on the face of the piece to be cut which is opposite to that facing the torch. The technological background is finally illustrated by documents JP-A-60 052985 and US-A-3 492 552.

Document JP-60 052985 presents a method for forming an edge with a curved groove, by providing for the successive passage of a torch with a vertical axis to obtain a straight cut, then of a transversely oblique torch to obtain a cut at 45 degrees. , and finally a fusion torch to form the concave edge. Document US-A-3,492,552 describes a digital device for controlling the position of a torch relative to the workpiece.

The invention relates more particularly to 1 Oxycutting at high speed of thick steel parts. It will be understood that the existing techniques are greatly limited in performance, both in terms of the thickness of the workpiece to be cut and the speed of flame cutting.

The invention aims to design a flame cutting technique to avoid the aforementioned drawbacks and / or limitations. The subject of the invention is therefore a method and a high-speed flame-cutting device for a thick piece of steel, which is capable of making regular and rapid cutting of thick pieces of steel, regardless of the thickness of the product to be cut. The technique sought must in particular be capable of carrying out slitting operations under technically and economically optimal conditions.

This problem is solved in accordance with the invention by means of a high-speed flame-cutting process for a thick piece of steel, in which a flame-cutting torch is moved, maintained at a determined height above the piece to be cut, and also moving, in synchronism with the movement of the flame cutting torch, a bleeding torch comprising at least one blade nozzle which passes inside the same flame cutting groove, said blade nozzle emitting by its edge at minus a jet of heating and / or oxygen cutting fluids striking the bleeding front by combining with the jet of oxygen cutting fluids emitted by the oxygen cutting torch to form a bleeding front having a broken line profile.

Thanks to the use of a tapping torch, operating inside the oxygen cutting tapping itself, it is possible to eliminate the aforementioned drawbacks of the great distance of the jet of heating and / or oxygen cutting fluids, and the oxy-fuel cutting power is also increased by increasing the number of oxygen cutting nozzles if one wishes to have very high power for cutting thick bodies, the thickness of which, for example, greatly exceeds 10 cm. The tapping torch can, depending on the case, be used as an injection nozzle (single or multiple), by projecting only heating fluids towards the tapping front.

Preferably, the jet of the flame cutting torch has a direction which is substantially perpendicular to the surface concerned of the part to be cut, while the or the jets of the tapping torch are inclined at an acute angle determined with respect to said direction.

Advantageously in this case, the tapping torch emits several superimposed jets of heating and / or oxygen cutting fluids attacking the tapping front at different acute angles, the value of which increases with the distance from the surface of the part attacked by the jet of the flame cutting torch. Thanks to the plurality of superimposed jets of oxygen cutting fluids attacking the same bleeding front at different acute angles, we can divide the length of the bleeding, that is to say the distance between the inlet and the outlet, in a certain number of sections or "no flame cutting", by assigning to each section a flame cutting nozzle with specific characteristics, so that the speed of flame cutting of the part is notably increased to reach that of a not. It is therefore the first time that one uses a real bleeding nozzle intervening inside the oxygen cutting groove throughout the cutting process.

Preferably, the synchronous displacement of the oxygen cutting and tapping torches is carried out by mounting their associated supports on a common carriage moving horizontally above the piece to be cut. In particular, the oxygen cutting and bleeding torches are vertically movable, the bleeding torch being retractable above the piece to be cut.

Provision may also be made for the tapping torch to be set into vertical vibration during at least part of the cutting process. Such a vertical vibration makes it possible to facilitate the progression of the tapping blade in the oxygen cutting tapping as it advances during the cutting process. The invention also relates to a device for implementation of the above-mentioned flame cutting process, the device being remarkable in that it comprises a carriage which can be moved horizontally, said carriage carrying supports for an oxygen cutting torch and a bleeding torch, the oxycut cutting torch overhanging the workpiece being arranged to emit a substantially vertical jet of oxygen cutting fluids, while the tapping torch comprises at least one blade nozzle arranged to move in the oxygen cutting tapping and emit by its edge at least an inclined jet of heating and / or flame cutting fluids.

Preferably, the supports for the oxygen cutting and bleeding torches are individually adjustable in the vertical position. In particular, the support of the tapping torch is suspended from a cylinder of vertical axis, said cylinder having a stroke allowing the rise of the blade nozzle (s) above the piece to be cut.

It may be possible to provide that the cylinder body supporting the tapping torch is connected to a vibrator which can generate vibrations of small amplitude in a vertical direction.

According to a particular embodiment, the blade nozzle of the tapping torch is unique, and has a network of internal channels extending obliquely between the upper facet and a slice of said blade nozzle. It will naturally be possible, as a variant, to provide nozzles with multiple blades, each of which is capable of emitting one or more jets of flame cutting fluids.

Preferably then, the internal channels are arranged to form at least one group associated with the same jet of heating and / or oxygen cutting fluids, in order to allow the passage of cutting oxygen and / or heating gases, and a coolant. In particular, the blade nozzle has several groups of internal channels intended to produce superimposed inclined jets the inclination of the channels with respect to the vertical being identical in the same group and varying from one group to the other, increasing from top to bottom of said blade nozzle.

In the case of oxycutting a continuous casting piece, it will be advantageous to provide that the carriage supporting the torch cutting and bleeding torches is movable transversely to the direction of continuous casting by being mounted on a main carriage which moves horizontally above the moving part, in the direction of continuous casting, said main carriage carrying a means of temporary securing to said moving part.

Other characteristics and advantages of the invention will emerge more clearly in the light of the description which follows and of the appended drawing, relating to particular embodiments, with reference to the figures in which:

- Figure 1 schematically illustrates an installation implementing the high speed flame cutting process according to the invention, here applied to the cutting of a continuous casting part, said part being shown in section by a vertical plane passing through oxygen cutting,

FIGS. 2 and 3 are sections respectively along II-II and III-III of FIG. 1, making it possible to better distinguish the arrangement respectively of the flame cutting torch and the bleeding torch during the cutting process,

- Figure 4 is a schematic view illustrating the tapping torch used in the context of the method of the invention, with the feed tanks fitted to the torch body, the torch nozzle being a nozzle flat blade,

FIGS. 5 and 6 are elevation views illustrating two different embodiments of the blade nozzle of the tapping torch, respectively with a unitary nozzle emitting several superposed oblique jets, and with several complementary nozzles each emitting an oblique jet,

- Figure 7 is a sectional view on a very large scale of the thick part being cut, showing the particular geometry of the bleeding front in a broken line resulting from the use of a blade nozzle emitting jets of superimposed fluids heating and / or flame cutting,

- Figure 8 is a side view of the aforementioned blade nozzle, and Figure 9 is a section along IX-IX of Figure 8, to better distinguish the arrangement of the internal channels of the blade nozzle, with here three groups of internal channels intended to produce superimposed inclined jets. Figures 1 to 3 illustrate a piece of steel such as a slab, billet or bloom being cut in accordance with the high speed flame cutting process of the invention. The part 1 to be cut has an upper surface 1.1 and a lower surface 1.2, and it rests horizontally on rollers 2. Being in this case a continuous casting part, the part 1 to be cut moves on the rollers 2 in a horizontal direction denoted 101.

In the figures, a device 10 can be distinguished which makes it possible to implement the high speed flame cutting process according to the invention.

This device comprises first of all a first carriage 11 moving by rollers 12 on a support R, a carriage which could be called a translation carriage. Indeed, the carriage 11 moves horizontally above the piece to be cut 1, and it is even mechanically linked to this piece during the implementation of the cutting process by a support 15 ending in a gripping device 16. The structure of this temporary attachment means may naturally vary as the case may be, and magnetic devices can also be used, as well as clamp systems which enclose the part to be cut on either side at its lateral facets. A second carriage 13 can be moved horizontally, being movable by its rollers 14 on the rails secured to the bottom of the carriage 11, the direction of movement denoted 100 of this carriage 13 being perpendicular to that of the carriage 11. The second carriage could thus be called 13 steering carriage, because it moves transversely to the part 1 in movement, to cut the part along the entire width and the entire thickness thereof.

The carriage 13 firstly comprises a support 19 of a flame cutting torch 30 of the traditional type. This flame cutting torch 30 overhangs the part to be cut, and it is arranged to emit a powerful jet denoted 36 substantially vertical from heating and flame cutting fluids. The support 19 is hung on a horizontal plate 17 secured to the carriage 13. We can see in FIGS. 1 and 3 the arrangement of this support 19, which comprises a baluster 31, ending lowerly by a collar 29 holding the flame cutting torch 30, which torch can be brought to the desired vertical position, which is adjustable with a locking in position by a screw 32. There have been noted 34 the supply pipes of the various oxygen cutting fluids. The jet 36 emitted by the flame cutting torch 30 thus achieves an attack on the part on an upper part of the thickness thereof. This part of the bleeding front is therefore essentially vertical. In accordance with an important characteristic of the invention, the carriage 13 also includes a support 18 for a tapping torch 20. This tapping torch 20 comprises a torch body 23 extending below by a blade nozzle 25 which is arranged for move in the oxygen cutting groove noted 1.3, and emit by its edge at least one inclined jet 26 of heating and / or oxygen cutting fluids. In FIG. 1, the progress 102 of the flame cutting process has been shown diagrammatically by arrow 102, and it can be seen that the blade nozzle 25 progresses inside the groove 1.3, the jets of heating fluids and / or oxygen cutting which it emits thus attacking the remaining part of the bleeding front which is noted 1.4. The body 23 of the tapping torch 20 is attached to a baluster 22 which is here connected to the rod 27 of a jack 21, in particular a pneumatic jack. The jack 21 has a vertical axis, and its body is fixed by bolting to the horizontal plate 17.

Thus, the flame cutting torches 30 and bleeding 20 are connected by their associated support 19, 18 to a common carriage 13 which moves horizontally above the piece to be cut, this common mounting then ensuring the synchronous movement of the two torches during the cutting process. The use of a jack also makes it possible to adjust the vertical position of the tapping torch 20, that is to say the precise position of the blade nozzle 25, so that its jets 26 are directed on particular points on the bleeding front with great precision. The stroke of the jack will preferably be chosen such that the bleed torch 20 can be retracted above the part when this torch is not used. The jack thus allows the ascent of the blade nozzle (s) 25 above the part to be cut.

We have also illustrated here a vibrator 28 mounted in the upper part of the cylinder 21 which supports the torch bleeding 20, said vibrator being arranged to generate vibrations of small amplitude in a vertical direction. Such a vibration makes it possible to facilitate the progression of the blade nozzle 25 in the groove 13 during the cutting process. As an indication, the amplitude of the vibrations could be of the order of 1 to 2 mm. The body 23 of the tapping torch 20 is also equipped with a plurality of conduits 24 serving to bring the various fluids concerned. Thus, and in accordance with an essential characteristic of the process of the invention, an oxygen cutting torch 30 and a tapping torch 20 are moved in synchronism, the latter comprising at least one blade nozzle 25 which passes inside the same the oxygen cutting groove 1.3, said blade nozzle emitting through its edge at least one jet of heating and / or oxygen cutting fluids 26 striking the bleeding front 1.4 by combining with the jet of heating and oxygen cutting fluids 36 emitted by the flame cutting torch 30 to form a bleeding front 1.4 having a broken line profile.

It will be noted in FIG. 1 that the jet 36 of the flame cutting torch 30 has a direction which is substantially perpendicular to the surface concerned 1.1 of the piece to be cut, while the jet or jets 26 of the tapping torch 20 are inclined by an acute angle determined with respect to said direction. We will return later in more detail to the importance of the inclination of these latter jets, in particular with reference to FIGS. 8 and 9. The blade nozzle 25 of the tapping torch 20 may be unique as illustrated in FIG. 5, or still multiple, as illustrated in figure 6.

In FIG. 5, the blade nozzle 25 has a network of internal channels 60.1, 60.2, 60.3 which extend obliquely between the upper facet 54 and a wafer 55 of said blade nozzle. The associated inputs are denoted 56.1, 56.2, 56.3, and the jets of heating and flame cutting fluids which exit through the edge 55 of the blade 25 are denoted 26.1, 26.2, 26.3. Preferably, the associated exit angles, denoted a 1, a 2 a 3 are different, and increase from the top to the bottom of the blade nozzle 25.

In FIG. 6, a variant has been illustrated in which the blade nozzle 25 is multiple, that is to say made up of three sub-assemblies of blade nozzles 25.1, 25.2, 25.3. Each sub-assembly has its individual fluid inlets, 56.1, 56.2, 56.3, respectively, and its heating and / or flame-cutting fluid outlets in the form of oblique jets, respectively 26.1, 26.2, 26.3. The internal channels 60.1, 60.2, 60.3 are then arranged accordingly in the thickness of these three components constituting the blade nozzle 25.

It will be understood that the number of internal channels, used to emit superimposed inclined jets, may vary in practice depending on the operating conditions encountered.

The views of FIGS. 5 and 6 are in reality schematic, insofar as the channels 60.1, 60.2, 60.3 are in fact each constituted by a group of channels associated with the various fluids of the same outlet jet. This will result in heating gases, cutting oxygen, and coolant. If it is desired to use the tapping torch as an injection nozzle (single or multiple), the fluids ejected and projected against the tapping front will then only be heating fluids.

Figure 4 provides a better understanding of the arrangement of the body 23 of the tapping torch 20 with regard to its fluid supply. The outline of the torch body 23 is shown in phantom, and it includes a number of feeders each associated with the different fluids involved. The different internal channels which are formed in the thickness of the head of the blade nozzle 25 have been symbolized by the reference 60. For the supply of these different channels, there is first of all a feeder 40 including an inlet for cutting oxygen 41 which is delivered by a pipe 43, a feed manifold 44 in heating gas, with inlets 45 and 46 corresponding to the combustible gas and to the oxygen, these gases being delivered by pipes 47, 48 associated, and finally a feeder 49 for supplying cooling fluid, for example water, with a water inlet 50 and a water outlet 51, the connections being provided by associated pipes 52, 53 respectively.

It should be noted that the blade nozzle 25 moves, during the cutting process, inside the flame cutting groove itself, which gives a considerable calorific advantage insofar as one obtains, so natural, preheating of the oxygen cutting fluids, which is particularly interesting for cutting oxygen. The cutting oxygen pipe is in fact subjected to heating by the heat of the oxygen cutting operations, and the radiant heat of the cut product if it is hot, as is the case with continuous casting slabs in the steel industry. It in turn transmits this heat to the oxygen cutting fluids playing the role of blade cooler and heat exchanger, thus allowing heat to be supplied to the combustion for which it is a requester.

As has been said above, it is the combination of the jets of the flame cutting torch and the tapping torch which makes it possible to perform a flame cutting at high speed, even for a very thick piece to be cut.

The inclination of the jets 26 of the tapping torch 20 has the effect of forming a tapping front 1.4 having a broken line profile. If the tapping torch 20 comprises a blade nozzle emitting a jet of oxygen cutting fluid 26, then the tapping front 1.4 simply consists of two segments, with a vertical segment associated with the jet 36 of the cutting torch 30, and an oblique segment associated with jet 26 of the tapping torch 20. However, in practice, it will be advantageous to provide a plurality of superimposed jets, and such an example has been illustrated in FIG. 7. In the present case, the blade nozzle 25 has three groups of internal channels making it possible to emit three superimposed jets of oxygen cutting fluids 26.1, 26.2, 26.3. Each of these jets gives an oblique conformation associated with the bleeding front 1.4. In this case, the area denoted AB is assigned to the external flame cutting torch 30, the jet 36 of which is perpendicular to the attack surface 1.1. The other sections, denoted BC, CD, DE, correspond respectively to the inclined jets 26.1, 26.2, 26.3 emitted by the blade nozzle 25 of the tapping torch 20. The corresponding angles of inclination with respect to the vertical are denoted al, a2 , a3. The broken line ABCDE, here consisting of four sections, forms the front of the oxygen cutting groove 1.4. In the case illustrated in FIG. 7, the three zones assigned to the three oxycutting steps of the blade nozzle 25, that is to say BC, CD, DE, are of substantially equal lengths. On the other hand, the area AB assigned to the outside torch is a little larger, because of the power given and desired for the flame cutting torch 30. However, it should be understood that the distribution can be modulated according to the circumstances encountered, and the angles of inclination a 1, a 2, a 3 will therefore be chosen to obtain the desired zone lengths. One could for example choose to give more importance to the last step by increasing the angle a3, in order to increase the length of the section DE. As will be understood, each jet of unit cutting oxygen fluids must ensure the cutting of only part of the thickness of the part to be cut, that is to say one section from the four aforementioned sections , this division of labor precisely allowing very high oxygen cutting speeds to be achieved despite the large thickness of the part to be cut.

The arrangement of the internal channels of the blade nozzle 25, which makes it possible to produce the three superimposed jets of heating and / or flame cutting fluids 26.1, 26.2, 26.3 will be better understood by referring to FIGS. 8 and 9.

It can be seen in FIG. 9 that the blade nozzle 25 of the tapping torch, here unique, has a network of internal channels which form several groups each of which is associated with a jet of heating or oxygen cutting fluids. In this case, an embodiment has been represented with three groups of internal channels, respectively denoted 60.1, 60.2, 60.3. Each of these groups itself comprises a plurality of inclined internal channels, the direction of which is the same for the channels of the same group.

Here we have referenced the internal channels of the first group 60.1 of channels, it being understood that this group which constitutes the first step is then reproduced, with however a different inclination each time.

One thus distinguishes, successively, moving away from the outlet section 55, a channel 60.11 associated with the cooling water inlet, a channel 60.12 associated with the cooling water outlet, a channel 60.13 associated with the heating fuel gas inlet, a channel 60.14 associated with the heater oxygen inlet (it will be noted that these last two channels 60.13, 60.14 meet before the outlet to open out by a single channel), and two channels 60.15, 60.16 corresponding to the cutting oxygen outlet. These six channels 60.11 to 60.16 form what we can call an oxycutting step, which step is characterized by its angle of inclination al. The other groups of channels 60.2 and 60.3 are arranged in a similar manner, but their inclination, respectively a2 and a3 increases progressively from the top to the bottom of the blade nozzle 25.

FIG. 8 makes it possible to distinguish the associated output orifices at the level of the edge 55 of the blade nozzle 25: for each group of channels associated with an oxycutting pitch, there is successively, from top to bottom, an orifice 61.11 associated with the outlet of the heating gas, and two orifices 61.12, 61.13 associated with the outlet of the cutting oxygen.

As has been said above, the flame cutting step can constitute an independent blade, or all of the flame cutting steps can be incorporated in one and the same flame cutting blade, as has just been described.

The simultaneous action of the oxycutting steps of individualized and different inclination contributes to distributing the total length of the oxygen cutting groove between the different oxycutting steps, preferably in an equal manner or in a manner proportional to the power of each oxycutting step nozzle, and thus reducing the cutting time of the total thickness to that of cutting the reduced thickness, treated by an oxy-cutting step nozzle.

As indicated above, the through channels of one or the other group of channels can be used to project only heating fluids towards the bleed front. It is thus possible to produce an injection nozzle, single or multiple, passing directly into the groove.

Finally, to facilitate the manufacture and connection of such a multi-channel blade, it is possible to use curved pipes, the upstream end of which is of round section (for easy connection to the manifold), and the remaining part of which is of flattened section (for minimum lateral dimensions).

It has thus been possible to carry out a process and a device for oxygen cutting at high speed allowing the cutting of steel parts of great thicknesses, in particular largely greater than 10 cm. The method and the device of the invention are of course applicable to a fixed part or to a continuous casting part.

The invention is not limited to the embodiments which have just been described, but on the contrary encompasses any variant incorporating, with equivalent means, the essential characteristics set out above.

Claims

1. A method of high-speed flame cutting of a thick piece of steel, in which a flame cutting torch is maintained, maintained at a determined height above the piece to be cut, characterized in that one also moves, by synchronism with the movement of the flame cutting torch (30), a bleeding torch (20) comprising at least one blade nozzle (25) which passes inside the same flame cutting groove (1.3), said nozzle in blade emitting by its edge at least one jet of heating and / or flame cutting fluids (26) striking the bleeding front (1.4) by combining with the jet of flame cutting fluids (36) emitted by the blowtorch flame cutting (30) to form a bleeding front (1.4) having a broken line profile.

2. Method according to claim 1, characterized in that the jet (36) of the flame cutting torch (30) has a direction which is substantially perpendicular to the surface concerned (1.1) of the workpiece, while the or the jets (26) of the tapping torch (20) are inclined at an acute angle determined with respect to said direction.

3. Method according to claim 2, characterized in that the tapping torch (20) emits several superimposed jets of heating and / or flame cutting fluids

(26.1, 26.2, 26.3) attacking the bleeding front (1.4) at different acute angles, the value of which increases with the distance from the surface (1.1) of the part attacked by the jet (36) of the flame cutting torch (30) .

4. Method according to any one of claims 1 to 3, characterized in that the synchronous movement of the oxygen cutting torches (30) and of the groove (20) is carried out by mounting their associated supports (19; 18) on a common carriage (13) moving horizontally above the workpiece.

5. Method according to any one of claims 1 to 4, characterized in that the flame cutting torches (30) and bleeding (20) are vertically movable, the bleeding torch (20) being retractable above the piece to be cut.

6. Method according to any one of claims 1 to 5, characterized in that the tapping torch (20) is placed in vertical vibration during at least part of the cutting process.

7. Device for implementing the flame cutting method according to any one of claims 1 to 6, characterized in that it comprises a carriage (13) movable horizontally, said carriage carrying supports (19; 18) of an oxygen cutting torch (30) and a tapping torch (20), the oxygen cutting torch (30) overhanging the workpiece being arranged to emit a substantially vertical jet (36) of oxygen cutting fluids, while the tapping torch (20) comprises at least one blade nozzle (25) arranged to move in the oxygen cutting tapping (1.3) and emit by its edge at least one inclined jet (26) of heating fluids and / or flame cutting.

8. Device according to claim 7, characterized in that the supports (19; 18) of the oxygen cutting torches (30) and of the groove (20) are individually adjustable in the vertical position.

9. Device according to claim 8, characterized in that the support (18) of the tapping torch (20) is suspended from a jack (21) of vertical axis, said jack having a stroke allowing the raising of the nozzle (s) blade (25) above the workpiece.

10. Device according to claim 9, characterized in that the body of the jack (21) supporting the tapping torch (20) is connected to a vibrator (28) capable of generating vibrations of low amplitude in a vertical direction.

11. Device according to any one of claims 7 to 10, characterized in that the blade nozzle (25) of the tapping torch (20) is unique, and has a network of internal channels (60.1, 60.2, 60.3) s 'extending obliquely between the upper facet (54) and a wafer (55) of said blade nozzle.

12. Device according to claim 11, characterized in that the internal channels (60.1, 60.2, 60.3) are arranged to form at least one group associated with the same jet of heating and / or oxygen cutting fluids, in order to allow the passage of cutting oxygen and / or heating gases, and a cooling fluid.

13. Device according to claim 12, characterized in that the blade nozzle (25) has several groups of internal channels (60.1, 60.2, 60.3) intended to produce superimposed inclined jets (26.1, 26.2, 26.3), the inclination channels with respect to the vertical being identical in the same group and varying from one group to another by increasing from the top to the bottom of said blade nozzle.

14. Device according to any one of claims 7 to 13, for one flame cutting of a continuous casting part, characterized in that the carriage (13) supporting the flame cutting torches (30) and bleeding

(20) is movable transversely to the direction (101) of continuous casting by being mounted on a main carriage (11) which moves horizontally above the moving part, in the direction of continuous casting, said main carriage carrying means (15, 16) for provisionally securing to said movable part.