DE3100271A1 - Method and apparatus for cutting up pieces of metal into narrower sections - Google Patents

Abstract

A pair of driven cutter rolls arranged one above the other and having annular wedge elements is used to cut a relatively hot piece of metal of rectangular cross-section into three or more narrower sections. The annular wedge elements dig into the piece of metal, which is transported in its longitudinal direction, and form V-shaped grooves in it. The angle between the flank which is closer to the cast side of the piece of metal to be cut up and on which the cutting force acts and a perpendicular to the rolling axis is larger than the angle between the other flank and the same perpendicular. The cross-section of the annular wedge element is thus asymmetric relative to the plane passing through the vertex of the wedge element and extending perpendicular to the rolling axis. <IMAGE>

Description

The invention relates to a method and an apparatus

for cutting relatively long, warm, rectangular cross-sections Metal pieces in the longitudinal direction, for example continuously cast steel slabs, to narrow Sections.

Usually steel products are made of the following machining sequence subject: First, in a steelworks, refined, molten steel is converted into Molds are poured and solidified there into raw blocks. The rough blocks formed in this way are heated uniformly in a deep furnace and then rolled into semi-finished steel. After cooling and surface treatment, the semi-finished steel is reheated and rolled out into the desired finished products.

Others, more recently used on a larger scale Process is molten steel from de., Steel melting furnace directly to semi-finished forms (or castings) continuously cast.

About the utilization and productivity of the tray during continuous casting To increase, the number of casting sizes must be reduced and the casting weight at of any size can be increased as much as possible. In fact, however, they vary Rolled products such as cold-rolled sheets ordered by customers regarding the thickness and the width to a large extent.

There are many shapes to meet this requirement in continuous casting required according to the desired number of sizes, especially widths, and these forms have to be changed frequently. Frequent changing of Continuous casting molds Naturally requires a considerable amount of time, so that the operating time of the continuous casting plant is decreased. This results in a reduction in use and productivity the deposit as well as the productivity of the workforce.

To solve this problem it has been proposed to increase the width of the To vary shape during continuous casting.

The continuous casting of an ingot with a width that is only the Half of the maximum possible width, for example, reduces productivity on half. This suggestion is therefore not advantageous.

So many different Widths are grouped together as possible and rolled as a single piece, the width of which is equal to that of the widest piece in the group; after that it will continuously cast piece with the help of a suitable device to the desired Cut wide.

The usual production of ingots comes in different sizes of semi-finished steel products are manufactured in the primary steelworks stage. At the However, continuous casting does not have this capacity to produce various Sizes if you don't change the shape you are using.

Therefore, in continuous casting, a wide piece of steel is first made here and cut / then later into narrower sections.

An example of this is the cutting of the casting in the longitudinal direction by means of a cutting torch. Another possibility is in JP-PS 83 023/76 describes where a casting is fed between a pair of horizontal rollers, each having one or more annular projections and one above the other are arranged. This creates one or more grooves with a V-shaped (wedge-shaped) Transverse cut formed in the longitudinal direction of the casting. After that, will that between the innermost points of the grooves in the top and bottom of the The remaining thin metal of the casting was cut by a cutting torch.

These processes enable the production of semi-finished steel in different widths by cutting a casting with a certain width in Longitudinal direction. However, flame cutting removes a significant amount of the material melted as slag, so that the process yield is reduced. The low one Cutting speed is based on the heat given off by the piece during the cutting process. This hinders the effective use of the heat that the casting after casting contains, so that the saving of energy for rewarming for subsequent Rolling is reduced. The flame cutting also lays the coarse-grained structure within of the casting free, which after subsequent oxidation as a defect in the finished product remains.

Another method of cutting material with a Therefore, there is no flame cutting in a certain width into two or more narrow sections. In this process, one or more grooves are made with a V-shaped (wedge-shaped) Cross-section cut into each surface of the piece in which this is between a Pair of horizontal, superposed rollers is passed, each have at least one annular projection. By repeating this process the upper and lower grooves are gradually deepened until the innermost points of the grooves meet at the end of the cutting process.

When cutting a piece lengthways into three or more narrow sections according to the method described last, two variants are suitable.

A first method is to subdivide the sections Continue in two parts until you get the desired number of sections will. The second method is to put the piece in the desired one at the same time Number of sections to be cut. The first method has several disadvantages. if If a piece is divided into two parts, the half sections are each arched. For practical reasons it is very difficult to walk along such a curved one Make a longitudinal cut on the surface. Furthermore, the frequent pass reduces by the cutting device the production efficiency. Hence the efficiency the second method is higher than the first method.

However, if you cut a long piece of metal, for example a steel slab, lengthways into three or more narrower sections at the same time in which using a pair of horizontal rollers with annular projections results in problems arise here as well. A cut through one piece with the two sides of the original piece, i.e. a cross-section on which the cutting force of the annular The protrusion has not acted, looks approximately like an asymmetrical one in cross-section Dog bones that vary in thickness when viewed across the width. If such a Piece is rolled for thickness reduction by paired, horizontal rollers, so has the product obtained has a large bulge, as the metal in different places is lengthened differently in width. This curvature not only makes it difficult subsequent rolling, but also degrades the quality of the finished product.

When cutting a flat section, for example a steel slab, care is required with the paired rollers with annular protrusions, so that all severed sections have a symmetrical cross-section or their Thickness irregularities are minimized across the width.

In contrast, the invention is based on the object of a method and a device for cutting a piece of metal into three or more narrow ones To create sections with high efficiency and thereby the above disadvantages to avoid.

Furthermore, the curvature obtained in the severed section should be so far can be minimized so that subsequent rolling is not hindered and the quality of the finished product is not deteriorated.

The inventive method for cutting a relatively long, hot metal piece with a rectangular cross-section in the longitudinal direction in three or more narrower sections are made in such a way that the metal piece in the longitudinal direction by a pair of driven knife rollers with ring wedges arranged one above the other is guided so that the wedges in the top and bottom of the metal piece cut in and cut into this piece of metal wedge-shaped or V-shaped grooves. The groove that is closest to one of the foot sides of the original piece to be cut, i.e. the side that is not acted upon by cutting force is shaped in such a way that this Side closer to the groove flank compared to a vertical by a larger angle is inclined than the other groove flank.

To form such a groove, the corresponding, annular Wedge has a cross section that is opposite one through the pointed end of the wedge extending and perpendicular to the roll axis extending perpendiculars asymmetrically is. In particular, the one closest to the cast side of the original piece to be cut The lying wedge flank is beveled at a greater angle than the other flank.

When cutting according to the above procedure, the cutting section has with the cast side of the original piece the following cross-section: The cut side of this section, i.e. the side opposite the cast side of the piece rolled by the rolling flank provided with a larger cone angle. With the oscillation plane including a considerable amount of orizontal components, the one with the blunt results inclined wedge flank rolled part of a plate, which as with usual paired rollers is rolled. Therefore, the metal flows into this part in the longitudinal direction of the section, which prevents an increase in thickness. This results in a cross-section with minimal variation in thickness in width direction.

Therefore, even the portion with the casting side of the original piece no significant curvature during subsequent rolling between the paired horizontal ones Rollers. This reduces the rolling frequency and increases productivity. The limited one Metal flow in the width direction increases the cutting accuracy.

The two sides of a section that is not a cast side of the original piece has, are rolled through the other wedge flank, the angle is smaller or more pointed.

Therefore, metal is built up in these areas. This metal structure is substantially symmetrical about the longitudinal axis of such a section, so that result from the subsequent reduction in thickness between the paired, horizontal ones Rolling does not result in any disadvantageous curvature.

The invention is described below with reference to the accompanying drawing explained in more detail. The figures show: FIG. 1 a schematic cross-sectional view for explanation, as with a pair of well-known rollers with an annular wedge cut a piece of metal into narrower ones Sections Figure 2 is a cross-sectional view of three sections below Use of the rollers according to FIG. 1 cut from a wider piece of metal have been.

Fig. 3 is a schematic cross-sectional view for explaining how According to the invention, a metal piece is cross-sectioned into narrower sections, Fig. 4a a cross section or a plan view of a section in the cut state.

4b shows a cross-section or a top view of the same and 4b ' Section in which the two sides are trimmed, Fig. 4c shows a cross section or a reflected light of the same and 4c 'section after being flattened by a pair Horizontal rollers, FIG. 5 shows a cross section of an embodiment according to the invention a knife roller, Fig. 6 is a detailed cross-sectional view in enlarged Scale of a knife roller according to the invention with an annular wedge, FIG. 7 a cross-sectional view similar to FIG. 6 of an annular wedge, in which the contour one flank is formed by a kinked line and the outer flank has a greater angle of inclination than the sections of the inner flank, Fig. 8a are cross-sectional views of annular wedges, and 8b the contours of the Flanks are formed by curved lines, with convex outer and Inner flanks (Fig. 8a) or concave outer flank and convex inner flank (Fig. 8b), FIG. 9 shows a top view of a device according to the invention for cutting up Pieces of metal and FIG. 10 is a front view of a knife roll stand as part of FIG Device according to FIG. 9.

Fig. 1 shows the usual technique of cutting a relatively hot one Metal pieces into smaller pieces. An annular one provided on a knife roller 21 Projection 22 has the shape of an annular wedge in cross section, both of which Flanks are inclined at the same angle e. The wedge 22 is thus in cross section symmetrical. There are two such driven knife rollers arranged one above the other 21 is provided, and a metal piece 1 transported in its longitudinal direction is passed between the paired knife rollers 21. This will cut the wedges into the top and bottom of the metal piece and form V-shaped grooves there 2. In general, the metal piece 1 is repeatedly passed through the rollers 21, so that the groove 2 is gradually deepened until it is completely cut through. This cut is made at a high temperature. If the piece of metal is made of steel, for example, the cutting temperature is from 700 to 1300 ° C.

Fig. 2 shows the cross-sectional shape of three sections into which a wide metal piece with the help of the paired knife rollers with the ring-shaped wedges is subdivided according to FIG. The middle section 4 is essentially symmetrical Thickness variation with respect to its central axis on. In comparison this is a change in thickness in the cut side sections 5, the each have a side 3 of the original metal piece on which no cutting force has acted (hereinafter referred to as free side 3), with an increase in Cut side 7 before.

This asymmetrical variation in thickness is amplified when the metal piece is cut in the usual manner above.

Investigations to determine a method are within the scope of the invention been carried out, with the help of which a piece of metal into three or more narrower ones Pieces cut using paired knife rollers with annular wedges without causing an unbalanced variation in thickness; in In this context, attempts have been made to understand the mechanism causing such unbalanced thickness variations to occur. These investigations led to the following findings. If a wide piece of metal, for example a steel slab or plate into three or more narrower pieces using the process is cut according to FIG. 1, the cutting effect of the annular Wedge 22 the metal to form a V-shaped groove. The displaced metal flows in the longitudinal direction of the metal piece 1 and is reinforced at the same time in the thickness direction. Due to this thickness reinforcement, the two lateral sections 5 are each with free side 3 thicker on the cut side 7 on which the cut is made, and on the free side 3 thinner.

In the context of the invention it has been shown that such an unbalanced Variations in thickness can be excluded by changing the cross-sectional shape of the annular wedge 32, which cuts off the section with the free side 3, according to Fig. 3 is asymmetrical. In this embodiment, each knife roller has two annular ones Wedges 32 to get the Cut piece of metal 1 into three sections. The angle (Teilflankenwin] cel) 81 and 62 between the flanks 34 and 35 and a vertical line m passing through the pointed end 33 of the profile of the wedge 32 runs and extends perpendicular to the axis 1 of the knife roller 31 are different. The angle # 1 of the flank near the free side 3 (hereinafter referred to as outer flank 34 designated) is greater than the angle 82 of the adjacent, opposite flank (hereinafter referred to as inner flank 35).

The horizontal component of the length of contact L between the wedge 32 and the portion is L x are1 or L x are2.

Therefore, in the protruding annular splines 32, the horizontal component is the contact length is greater for the outer flank 34 than for the inner flank 35. Therefore the part of the section which contacts the outer edge 34 results in a plate which as rolled between conventional horizontal rolls. As is well known, flows in the usual Plate rolling the metal mainly in the rolling direction. By increasing the angle 81 of the outer flank 34, more metal flows in the direction in which the groove 2 is extends where the outer flank 34 contacts the plate, so that the reinforcement of the The thickness of the metal piece 1 is reduced. Therefore, the unbalanced thickness variation are reduced so far that in the subsequent rolling to reduce the thickness none significant curvature occurs. Thanks to the small inside flank angle e2, the middle section 4 to a much stronger metal construction. This metal structure results essentially symmetrical to the width, so that there is no curvature, when the section 4 is rolled by horizontal rolling to reduce the thickness will.

After cutting off a relatively hot, wide piece of metal, for example a steel slab into narrower sections according to the above procedure, a trimming is carried out to provide the side of the section with a Leap to flatten due to the cutting process, then the trimmed section becomes to reduce the thickness rolled by means of paired horizontal rolls. Fig. 4 shows these working steps at an outer section 5, which in this illustration is a section from the right Page in Fig. 2 is.

Fig. 4a is a cross section of a section 5 immediately after Cutting with a cut side 8 with a projection 9 and a flat free Page 3. In this case, the section 5 according to FIG. 4a 'is strongly curved.

Figure 4b is a cross-section of a section 10 after trimming on both sides 3 and 11 by means of a pair of vertical rollers for disposal of the projection 9. Since the two sides 3 and 8 are trimmed, the flat free side 3 stronger than the cut side 8 with the projection 9 becomes the curvature of the trimmed section according to FIG. 4b 'with respect to the section according to Fig.

4a 'vice versa.

Fig. 4c is the cross section of a portion 12 with uniform Thickness due to the reduction in thickness by rolling the trimmed portion 10 by means of a pair of horizontal rollers. With these rollers the thicker one will be Part longer than the thinner part, so that the curvature of the rolled flat Section 12 according to FIG. 4c 'also reversed with respect to the section according to FIG. 4b' will.

For efficient production, the asymmetrical thickness variation in section 5 are reduced to such an extent that the curvature in this state, i.e., in Figures 4c and 4c 'can be reduced to substantially zero. By According to the invention, it is selected suitable flank angles 81 and i2 for the ring wedge possible, the symmetry deviation regarding the thickness variation to decrease in the desired way.

The above description relates to an embodiment in which the piece of metal is divided into sections. The same is true in the Cases where the metal piece is divided into four or more sections.

The ring wedge that cuts off the outer section with one free side, receives a larger flank angle on the outside than on the inside. Of the Ring wedge that cuts off a section with two cut sides has equiangular ones Outside and inside flanks. Fig. 5 shows an embodiment of such a knife roller. For cutting a piece of metal into sections, this knife roller 41 has two outer ring wedges 42 at the opposite end portions and two therebetween lying, inner ring wedges 43 on. Each outer ring wedge 42 is the outer one Flank angle 61 larger than the inner flank angle 82 for the inner ring wedges 43, the angle e3 of both the outer and inner flanks is equal to the inner flank angle 82 of the outer ring wedges 42.

6 shows a detailed cross-sectional view of an annular wedge to cut off a section with a free side.

To improve the effect according to the invention, the outer flank angle should 1 should be as large as possible, provided that the angle a at the wedge apex (= 01 + 82) is from 30 to 900. When the wedge apex angle a # 1 exceeds 900, becomes the height (h in Fig. 2) of the roof-like projection on the cut side so great that many trimming passes are required in order to process this Turn off the advance. Furthermore, if the cut is made with such a wedge, the knife roller is exposed to such a large reaction force that the cutting device is which must be big enough to withstand.

In addition, the desired V-shaped groove cannot be formed. det until the piece of metal has not passed between the knife rollers several times is; this worsens the working efficiency. If, on the other hand, the wedge apex angle a is smaller than 300, the ring-shaped wedge does not have sufficient strength and wears out quickly.

The wedge apex angle a in the range from 30 to 900 becomes the outer flank angle 81 and divided the inner flank angle. These angles must be chosen in such a way that that the thickness variation obtained in the cut piece is small enough, so that the section 12 in the rolled state according to FIG. 4c 'does not have any significant curvature learns.

According to the invention, the angle # 1 should preferably be from 0.52cd to 0.92 «.

If the maximum thickness of the metal piece is II, then one will be obtained high cutting efficiency if the width g of the chisel tip is less than or equal 0.05 H (£ # 6 0.05EI) or preferably 0.01 H to 0.04 H (# = = 0.01H to 0.04II) amounts to.

According to the above description, the wedge flanks are in their contour straightforward, but the invention is not limited to this. For example the flank shape can also be kinked or curved. Fig. 7 shows an embodiment with kinked flank. 8a and 8b show embodiments with curved Flanks. The wedge flank angle in these embodiments (hereinafter referred to as equivalent wedge flank angle) is defined in the following manner. In the cross section of the ring wedge, a line segment q is derived in such a way that the area which is marked by a line segment m through the pointed end of the wedge (center point / # in Fig. 6) and perpendicular to the rolling axis, through the contour n of the wedge flank, which through the kinked or curved line is formed, and by a baseline p the Wedge flank is equal to the area defined by the lines?, Q and p is defined. The between the line segment q and the line segment m angle formed perpendicular to the rolling axis is called the equivalent wedge flank angle 8e1 or 8e2 defined. In the embodiments according to FIG. 7, the outer wedge flank angle is 81 greater than the equivalent internal wedge flank angle e e2 in the embodiments 8a and b, the equivalent outer wedge flank angle 8e1 is greater than that equivalent internal wedge flank angle Oe2. In the ring wedge according to FIG. 8a, both the inside as well as the outside flank convex. The ring wedge according to FIG. 8b has a concave outer flank and a convex inner flank.

The piece of metal to be cut must be kept at a high temperature, so that the ring wedge is easy to form a wedge-shaped groove in the metal piece can cause plastic deformation. If the piece of metal is made of steel, the cutting temperature is preferably about 700 to 13000C. When the piece of metal is continuously cast, this is directly from the continuous casting plant of the cutting device fed so that it can be cut before cooling. In case it cooled down is, the piece of metal should be put back in a so-called so-called deep furnace for cutting suitable temperature to be heated.

9 shows a cutting system according to the invention for pieces of metal with knife roll stands 51 and 52, a transport device 81 and a guide device 91.

The two knife roll stands 51 and 52 are arranged in tandem. The cutter rolls 53 and 54 in each stand are driven by a reversible motor 55 driven via a reduction gear 56, cardan joints 57 and a spindle 58.

Fig. 10 shows a front view with details of the knife roll stands 51 and 52. The stacked, paired knife rollers 53 and 54 are rotatably supported in a housing 61 by means of bearings 62 and 63, see above that they can be moved up and down. The knife rollers 53 and 54 each have three ring wedges 64, 65 and 66. With the two lateral ring wedges 65 and 66 the outer flank angle is greater than the inner flank angle according to the above Description. In the case of the middle ring wedge 64, the outer and inner flank angles are equal and also equal to the inner flank angle in the outer ring wedges 65 and 66.

The right end 67 of the roller is connected to the universal joint 57.

The distance between the rollers or the depth of cut of the annular wedges 64, 65 and 66 in the section is fastened to the housing 61 by a screw device 71 set.

This screwing device 71 has a worm gear winch 76 which either with the aid of a motor 72 via a chain transmission 73 with a reduction gear or driven by a motor 75 with a reduction gear. By raising and lowering a screw 77, the winch 76 moves that with the screw 77 connected bearings up and down. There is a winch 76 on each side which are connected to one another by a connecting rod 78.

According to FIG. 9, the conveying device 81 conveys the metal piece 1 in its longitudinal direction and is at the inlet end and at the outlet end of the knife roll stands 51 and 52 provided. The transport device 81 has a plurality of rollers 82 which are arranged at suitable intervals in the conveying direction. The rollers 82 have each have a sprocket 83 and are connected to one another via a chain 84 so that that they are driven simultaneously by means of a reversible motor 85.

Adjacent to the knife mill stands 51 and 52 are at the entry end and the outlet end each have a guide device 91 with a pair of guide plates 92 is provided, which can be moved over the transport path and is connected to one end of an im Cross-section of square support part 93 are connected. The support part 93 is on slidably attached to a guide rail 94, the opposite end of the support part is connected to a drive 96 via a connecting rod 95.

The operation of the cutting device according to the invention is as follows: At the beginning, the gap between the knife rollers 53 and 54 is set so that that the cutting depth required for the first pass is achieved. The space between the rolls on the second knife roll stand 52 is less than that on the first stand 51, so that the wedge-shaped groove formed by the first frame 51 on the second Roll stand 52 is deepened.

To ensure cutting with the exact width, the Metal piece 1 are fed to the knife roll stands 51 and 52 in the correct position. For this purpose, the guide plates 92 are preset in a suitable manner in which the Guide device 91 is moved forwards and backwards with the aid of the drive 96, so that the metal piece 1 is held in the correct feed position.

Then the transport device 91 is operated to the metal piece 1 to be introduced into the first and second knife roll stands 51 and 52. In these Scaffolds 51 and 52 cut the annular wedges 64, 65 and 66 from above down into the metal piece 1 to form wedge-shaped grooves 2.

This will cut the piece of metal into the desired narrower sections cut up. If the cut is not made in a single pass, the knife rollers 53 and 54 and the rollers 82 of the transport device 81 in reverse Direction driven to guide the metal piece 1 in the opposite direction. In this pass through the second and the first roll stands 52 and 51 in this Sequence, the wedge-shaped groove 2 is deepened in the section 1. The piece of metal 1 is repeatedly guided through the roll stands 51 and 52 until the cut is completed.

Example A piece of metal is divided into three sections below Cut up conditions: 1) Metal piece quality: Pure carbon steel Shape: Slab (thickness 200 mm, width 1.5 m, length 6 m) temperature: 1000 ° C.

2) Knife rollers flank angle of the annular wedges a) According to the invention, annular wedge (81 7 e2> corresponding to the shape according to FIG. 7; outer wedge flank angle 81 = 250 Inner wedge flank angle 92 = 21o (equivalent angle) b) conventional ring-shaped Wedge (# 1 = outer - wedge flank angle e1- = 230 -.

Inner wedge flank angle 82 = 23 3) rolling pass Pass no. 1 2 3 4 Number of cuts 70 60 40 28 (top and bottom in total in mm) Table I below shows the Schnittergebaisse under the above conditions: I le 1 form of the ring-shaped structure on the structure of the genes: eils Mitt # elab- both sides- ~~~~~~~~~~~~~~~~~~~~~~ schnJUt (mm) sections (mm) Invention 0.8 6.0 State of the art 9.6 8.5 How yourself from Table I, the metallic build-up (d in Fig. 2) becomes strong. reduced, when the outer wedge flank angle 81 is greater than the inner wedge flank angle # 2 In the present example, the metal structure decreases by 29 t when the outer Keli flank angle is increased from 230 to 25 ° When flat rolling by the paired horizontal rollers (cf. FIGS. 4c and 4c ') according to the prior art obtained section has a curvature of 300 mm, while the curvature in the erfindungsgeinäß received section is only 50 min. This obtained according to the invention, slight curvature does not pose any problem during subsequent rolling.

Claims (5)

Method and device for cutting pieces of metal into smaller ones Sections of claims 1. Method of cutting a relatively warm piece of metal (1) with a rectangular cross-section into three or more narrow sections by training of wedge-shaped grooves in the longitudinal direction of the metal piece, d a d u r c h g e k e nn z e i c h n e t that the angle (e1) between (m) a perpendicular to the rolled piece Line / and the free side (3) of the metal piece fixed to the cast-free side (3) adjacent flank / groove (2) is larger than the angle between the other flank 1 and the same vertical line (m). 2. Device for cutting a relatively warm piece of metal (1) with a rectangular cross-section into three or more narrower sections, thereby characterized, (a) that a knife roll stand (51 and / or 52) with a pair on top of each other arranged, rotatable knife rollers (53, 54) is provided, each of several arranged around the roller, annular wedges (32; 42, 43; 64, 65 66), the in the axial direction of the roller at a distance to each other along the roller are arranged, (b) that two wedges are outer wedges (32; 42; 65, 66) which are closer are at the respective ends of the roller, (e1) (c) that the flank angle / the to the flanks of the outer wedges facing the roller ends is greater than the flank angle / the other flanks of the outer wedges and (e2) (d) that on the entry and exit side of the knife roll stand (51 and / or 52> a transport device (81) for conveying of the metal piece to be cut (1) through the frame in the longitudinal direction of the metal piece (1 is Norse 3. Apparatus according to claim 2, characterized in that the Apex angle a of the outer wedges (32; 42; 65, 66) as the sum of the flank angle (e1) near the end of the roll and the flank angle (e2) of the outer flank is from 30 to 900 and the flank angle 81 is from 0.52a to 0.92a. 4. Apparatus according to claim 2 or 3, characterized in that the tip of each outer wedge is flattened, and that the width s # of this flattening from 0.01 H to 0.04 H, H being the maximum thickness of the in the roll stand is to be cut metal piece (1). 5. Device according to one of claims 2 to 4, characterized by a guide device (91) for guiding the metal piece to be cut, the the knife roll stand (51 and / or 52) is arranged adjacent and a guide plate (92) which is reciprocable transversely to the direction in which the to cutting metal piece (1) is conveyed by the transport device (81).