FI63530B - FOER FARAND OCH ANORDNING FOER KRYMPVALSNING AV METALLSTAVAR - Google Patents

Description

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q Patent granted on 11 July 1983 «\3 \ § (45) Patent oeddelat 'v ^: (51) ICv.lk.3 / lnt.C1.3 B 21 B 1/00 FINLAND —FINLAND (21) P» M * i «Lh.k * mu * -P» t * nttniökn »ng 3 ^ 65/7 ^ (22) Hakemliplivft - Amttknlngadag 29-11-7 ^

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National Board of Patents and Racers .... ... .

_. . '. __ (44) Date of issue: 31 03

Patent and octaggeratyrene '7 Amekan utitgd och utijkrifton pubitc ^ ad JX: i · 0: 3 (32) (33) (31) Requested * that <Begin priority (71) M.I.M. Rolling Consultants (H.K.) Limited, c / o Universal Corporate Services Limited, Room 309, Chartered Bank Building, Des Voeux Road,

Hong Kong, Hong Kong (HK) (72) Raymond Oliver Sayer, Townsville, Queensland, Australia-Australien (AU) (7U) Leitzinger Oy (5U) Method and apparatus for metal rod reduction roller sex -Förfarande och anordning för krympvalsning av metallstavar

The invention relates to a method for shrink-rolling a metal rod from a starting piece with a relatively large cross-sectional area by a plurality of successive rollers, each of which two adjacent rollers being provided with parallel, uncalibrated , wherein the bar material, when entering rolling mills with uncalibrated rollers, has a substantially rectangular cross-section, the main axis of which runs perpendicular to the working surfaces of the rollers and the side axis of which runs perpendicular to the main axis.

From the publication "The Wire Industry", February 1968, pages 149/150, it is known from many years of experience that the rod material can be alternately shaped into rollers of square and oval cross-section with calibrated rollers, especially in fully automatic rolling mills. In this way, the problems associated with feed control can be reduced, as can the number of rolls required to produce the final product 63530.

According to the above-mentioned publication, the bar is alternately rolled into a square and rectangular cross-section.

In this case, in rolling, the surfaces of the bar material passing from the two adjacent rollers, parallel to the work surfaces of the rolls, run to the next roll at right angles to the work surfaces of its rolls, because the axes of successive roll pairs are perpendicular to each other and the bar material “That publication also describes the use of input controllers, although they are not further defined.

The disadvantage of this known method is that the number of rolling mills cannot be reduced in all cases as would be desired. This is because the reduction of very large cross-sections leads to a deterioration in the quality of the final product, for example in the form of various tears or, correspondingly, to indentations on surfaces which are not in contact with the rollers. Sharp edges are generally required of the bar material, so the above disadvantages are considerable.

The object of the invention is to provide a method which avoids the drawbacks described above and which can widely use non-calibrated cylindrical rolls for rolling rod material, which method achieves a large reduction in cross-section without error as much as possible and which is economical in practice and requires little space. The method is applicable to a number of metals, in particular copper, steel, aluminum and their alloys. The method is particularly suitable for automatic rolling mills and can be applied to existing rolling mills by relatively small means.

The object of the invention is solved in such a way that when the rod material is fed into the uncalibrated roll silicon the main axis is 1.5 to 2.5 times as long as the side axis and after modification the rod material fed from the uncalibrated roll the main axis running parallel to the working surfaces of the bypassed rollers is 3 63530 1.5 to 2.5 times as long as the side axis running perpendicular to it.

The method according to the invention does not suffer from the disadvantages described above and an optimal aspect ratio is obtained. In each compression, not exactly a completely rectangular cross-section is obtained, but a so-called round-rectangular rectangle. In each compression, this circular rectangle is reduced to a smaller cross-section, which, however, has the same basic shape. The cross-section of the rod material coming out of the rolling mill is thus of the same shape as the rod material fed into the rolling mill.

By correctly selecting the ratios of the longitudinal and short sides, i.e. the main axis and the minor axis, the invention can avoid the difficulties encountered in rolling with uncalibrated rolls.

The method of the invention comprises: (a) transmitting said primer longitudinally through a series of successive pairs of roller chairs comprising at least one pair of two cylindrical parallel, non-grooved rollers and an input guide capable of supporting said primer as it enters the rollers.

(b) forming said initial body prior to its arrival at said input guide such that its transverse cross-sectional profile includes a short axis which is the shortest dimension of the profile and a long axis substantially at right angles to said short axis, said long axis being one and a half to two and a half times longer than said short axis} (c) feeding said initial piece to said non-grooved rollers 63530 by said input guide such that said short axis is substantially parallel to the machining surfaces of said rollers; (d) spacing said rolls at such a distance that the transverse cross-sectional area of the initial body exiting said rolls is less than the cross-sectional area of the initial body approaching said rolls and further such that the transverse dimension of the outgoing body parallel to the short axis of the incoming body one and a half to two and a half times longer than the transverse dimension of said outgoing body parallel to the long axis of the incoming body.

Comparing this method to the prior art of using circumferentially grooved rollers to form bars, the invention offers several important advantages, e.g., (1) As indicated above in this specification, conventional "groove bar rolling" may have difficulties if two corresponding coil grooves are slightly oblique to each other. or if the inlet guide of those grooves is slightly away from the correct direction with respect to the grooves, or if the rollers are mounted a little too close to each other, in which case the incoming starting piece tends to fill the grooves forming the rolling space too much. If some of these difficulties occur, they tend to cause rib-like bulges in the longitudinal direction of the initial body; these collapse due to the compressive force and compress during the next compression step, forming longitudinal fractures or cracks in the finished rod, commonly known as "folds" or "false ones". The use of the non-grooved rollers according to the invention eliminates these disadvantages simply because, since the rollers do not have grooves, they cannot be created.

63530 5 (2) The formation of a bar by the method according to the invention consumes less energy in the use of a rolling mill. These components are directly opposite to each other, and thus perform some useless work on the part.The invention eliminates such frictional abrasion and the work on the part manifests primarily as free deformation of the metal because the working load on the part is directed in one direction (usually in the direction of the roller machining surface). ) without opposing compressive loads and without any expansion of the metal in a direction parallel to the machining surface of the roll. such obstacles. In other words, the prior art of forming a bar using grooved rolls is due to the notion that in order to reduce the cross-sectional area of the part (which is paramount in any shrinking process) it is considered essential to close the part so that the part is subjected to maximum compressive loads "during grooving". to move (at least initially) completely inwardly toward its own longitudinal centerline, or rather the longitudinal centerline of the body. This earlier notion that efforts should be made to prevent radial outward or propagation movement of metal particles appears, on the surface, to be an almost irresistible notion in this field of technology. One would naturally expect, if the purpose of the shrinking process is only to shrink an output element with relatively large cross-sectional dimensions into a rod with smaller such dimensions, that it is almost self-evident that all compressive loads applied to the part should be such that they compress the part or in as many directions as possible, in which case the deformation of the metal ultimately manifests itself merely as a longitudinal enlargement of the body.

The invention differs sharply from the previous concept of bar crushing in that in each successive pair of roll chair pairs (or as many as necessary) a piece is subjected to a compressive load in only one direction 63530 (normally in the direction of machining surfaces of non-grooved rolls); and in the direction at right angles to this direction, the body is allowed to expand in a substantially transverse direction and, in addition, this expansion is arranged to be completely unobstructed; wherein the amount of free expansion of the piece in said second direction is limited (to an amount suitable for use in the next pair of rollers in the direction of travel), this limitation not being performed by preventing the piece from expanding in any way, but only by placing two pairs of non-grooved ceases to self simply because its previously exerted forces cease to act before excessive lateral expansion occurs.

(3) It has been shown experimentally that the method according to the invention, in which the body is allowed to expand laterally, the formation process of the rod. can be performed using a smaller number of shrink-rollers. For example, in the case previously referred to in the description (reduction of a copper wire ingot to an 8 mm diameter bar), sixteen rollers with rollers were provided in the usual manner. The method of the present invention had a sufficient number of fourteen rollers, all of which, with the exception of the first, i.e., reshaping, rolling mill, and last, i.e., finishing rolling, were provided with non-grooved rolls and were used in accordance with the method disclosed herein. Although this saving in the number of rolling mills is not large, it is important because the equipment is expensive. The savings are largely due to the fact that the use of non-grooved rollers reduces the number of unknown factors that must be taken into account mathematically when calculating the optimum amount of change (metal shrinkage) per pass. When grooved rollers are used, the effective diameter of the roller is indeterminate, because the metal is machined not only along the bottom diameter of the grooves but also along the side walls of the grooves. When using flat cylindrical rollers without grooves, the effective diameter of the roll can be calculated exactly, so that the best possible shrinkage of the metal can be easily calculated. 1

When a roller without grooves wears, it can be easily repaired and smoothed by simple grinding, whereas when using grooved rollers, wear in the grooves requires repair more often as a result of frictional wear due to abrasion, and this repair work requires extensive relatively complex machining to form grooves. again.

(5) Since rollers without grooves can only be smoothed by grinding, their machining surfaces can be made as hard as appropriate, thus extending the useful work steps between leveling the rolls.

(6) When using non-grooved rollers, the intervals between the smoothing steps of the rollers are further extended because the entire cylindrical surface of the rollers can be utilized by simply adjusting the input guides laterally axially with the rollers. When using grooved rollers, the only usable machining surfaces are those formed by the groove bottoms and sidewalls.

(7) When using conventional grooved rollers, the grooves must be formed for each contraction passage specifically for the task in question; e.g. in the manufacture of an 8 mm rod. The rollers can be adjusted to some extent to prevent excessive groove wear and the like, but if a different task has to be performed (e.g. to make a 10, 12 or 13 mm rod), it may happen that the whole roll row has to be changed or some rollers are difficult to bypass; while when using non-grooved rollers, only the final finishing roller needs to be replaced. For all other rollers, all you need to do is simply adjust or remove the distance between each pair of rollers on an unnecessary roller.

(8) In non-grooved rolling, the body emanating from any non-grooved roll pair necessarily has two opposite surfaces, both of which are flat and parallel, thus forming a symmetrical and geometrically constant shape which gives better Kap-palestability in input guides compared to oval, diamond-shaped to other cross-sectional shapes that are generally provided by grooved rollers because they tend to provide the greatest possible shrinkage of metal per pass. This improved stability, in turn, helps ensure that the part moves precisely in the correct position to the rollers in direct contact with the specified input guide.

The invention will now be further described with reference to the accompanying drawings, in which: 63530

Figure 1 is a partially sectioned perspective view of an embodiment of an input guide that may be used to perform the bar rolling method of the invention;

Figure 2 is a central section of one pair of input guide rollers showing a non-grooved rolled starting piece therebetween. Figure 1 shows four such pairs of rollers.

Fig. 3 is a perspective schematic diagram showing two adjacent steps in the grooved rolling of a part with the input guides omitted.

The figure »+ shows a typical sequential order of the profiles of the part, in which all the contractions except the last one have been performed by grooved rolling.

According to the drawings, the rolling mills for each constriction passage may be similar in the sense that each of them includes a pair of constriction rollers, arrangements for mounting and operating the rollers, and an input guide for transferring the rollers to the rollers.

The input guides can be of any conventional type, e.g. they can be as shown in Figures 1 and 2, each guide having an open-toped box-like frame 7 in which a plurality of paired guide rollers 8 can be mounted, grooved and spaced from each other that the through body indicated by reference numeral 9 fits between them and they support it. If the non-grooved rolling according to the invention, which is also the method according to our American patent application No. 306 M-09 (filed November 1, 1972), is preferably performed, the input guide rollers may be double grooved and otherwise as described and described in that application.

It can be seen from Figure 3 that the axes of the rollers 5 are placed at a right angle to the axes of the rollers 6 of the next rolling mill. It is advantageous to use such an arrangement in which the roll axes of every second rolling mill are placed at an angle of 90 ° to each other. Such an arrangement is already commonly used in conventional "groove rollers", where these are known as "alternating horizontal / vertical rollers". Alternatively, the roll axes throughout the rolling system may be parallel, with members arranged to rotate the piece 90 ° between successive rollers. This method is also known in the art.

It is clear that the number of rolling or contraction steps in a complete bar rolling operation depends to a large extent on the transverse dimensions of the output elements and the dimensions required of the finished bar. The series shown in Figure 4 shows the starting element profile A, which is substantially square, with eleven four-sided V-stage profiles B to L and the finished bar profile M. Figure 3 can also be seen as showing three of these profiles, e.g. F, G and H.

As previously shown, it is preferred that as many shrinkage runs as possible be performed "groovelessly", although performing only one step in this manner provides some benefit.

With the exception of the last step (reduction of the profile L to the bar profile M), all the steps shown in Fig. 4 have been performed without grooves. However, it is clear that if the bars with the profile L form a useful commodity, all the steps can be performed without grooves. For example, steel bars used as purely tensioned parts of a structure may very well be L-shaped; under these conditions, an L-shaped bar may even be more advantageous because its flat sides would allow bolt holes to be drilled, press-fastened or welded to other structural elements, etc.

However, if the finished rod is to be M-shaped, it is preferable to carry out the final contraction step by means of conventional grooved rollers, as indicated by the broken lines 10 arranged in the profile L.

As well as the last contraction step (L-M), the first step can also be performed using conventional rollers, especially when the first step is intended to reshape the output element rather than reduce its cross-sectional area perpendicular to its longitudinal direction, e.g., a first step with a trapezoidal copper wire ingot to make its profile rectangular or nearly rectangular) can be performed using conventional rollers if desired.

Referring further to Figure 4, the shape of the output element A is changed by subjecting it to unidirectional compression of the non-grooved roll, the machining surfaces of the rolls being indicated by dashed lines 11. If this step is purely or largely deformed, the resulting body profile B has approximately the same surface area. than profile A. On the other hand, some contraction of the body can be achieved at this initial stage. In either case, the roll surfaces 11 are spaced apart so that the resulting profile B is a four-sided profile comprising two flat and parallel opposite sides 12 spaced equal to the short axis indicated by reference numeral 13 and two outwardly bulging opposite sides. 14, the maximum distance between which is the same as the long axis indicated by reference numeral 15.

Experiments have shown that the length of the long shaft 15 should not be more than n, two and a half times the length of the short shaft 13 of the same piece, otherwise there is a risk that the piece will get out of the right direction when entering the next (in the direction of travel) unpaired roll. Based on current data, the best possible ratio (at least in the case of a copper body) between the long and short axes is about 2.1 · 1.0.

In the queue according to Fig. 4, the piece with profile B is pressed in one direction between the non-grooved roll surfaces indicated by reference numeral 16, whereby a piece according to profile C is formed. In this profile (and in the following profiles in the direction of travel) the ratio between the long and short axes is preferably 2.1: 1 as described above. The following pressing steps (profiles D to E) are performed in the same way. The last compression step (from profile L to profile 8) can be a purely reshaping step or a step in which both reshaping and shrinkage take place.

The sequence of compression steps shown in Fig. 4 shows the so-called "abundant" or "strong" contraction known in the art, which means an exceptionally large reduction in the cross-sectional area of the body per compression step, but it has been shown that high aspect ratios (e.g. 1: 1) feeding the equipped part to the flat cylindrical rollers by means of a suitable inlet guide gives the passing part satisfactory stability, which means that the part does not tend to tilt or fall sideways with respect to the shrink rollers. is shown) in this case all obstacles to the lateral expansion of the body are avoided.

Where abundant shrinkage can be applied, it is naturally useful because it allows the output element to be converted to the shape of the final rod with fewer compression steps. It is clear, however, that the method according to the invention can equally well be applied when less strong or even "slight" contraction is preferred; this comes into play, for example, in the production of bars from special steels or other metals, which are generally not easily considered suitable for bar rolling.

The invention can be applied to both hot and cold bar rolling. In this case, cold rolling can be limited to deformation of the metal at temperatures below which back-conversion steps, e.g. regeneration or recrystallization, do not occur within a reasonable time (e.g. between successive compression steps), and hot rolling is performed at temperatures other than freshly limited crystallization can occur.

Claims (5)

A method for shrink-rolling metal rods of a starting piece having a relatively large cross-sectional surface in several successively arranged roll chairs, of which at least two adjacent roll chairs have parallel uncalibrated cylindrical rolls and the surfaces of the rod material leaving the front of the adjacent the roll chairs parallel to the working surfaces of the rollers extend into the subsequent roll chair at right angles to the working surfaces of the rolls, the rod material when inlet in uncalibrated rolls having a substantially rectangular cross section with a rectangular head axis and a right angular surface to the rollers side axis, characterized in that at the inlet of the rod material in an uncalibrated roll pair, the main axis is 1.5 - 2.5 times as long as the lateral axis and after reshaping at the outlet of the uncalibrated rollers, the rod material has a smaller relative to the inlet rectangle cross section. 0 ° rotated outlet rectangle cross-section where the main axis running parallel to the working surfaces of the passed rollers is 1.5 - 2.5 times as long as it is perpendicular to the lateral axis of this running rod material. 2. A method according to claim 1, characterized in that the intersection between the main axis and the side axis of the rectangular cross-section of the rod material running in and out of the unbalanced rolls is 2.1: 1. Apparatus for rolling metal rods in several consecutive rolling chairs, at least two adjacent rolling chairs each provided with parallel uncalibrated cylindrical rolls and the surfaces of the rod material leaving the front of the adjacent rolling chairs in parallel. with the working surfaces of the rollers, runs into the following rolling chair at right angles to the working surfaces of the rolls, these rolling chairs being provided with inlet guides extending into the roll nip for carrying out the method according to claim 1 or 2, characterized in that the cylindrical rollers (5) 6) spacing is set so that the rectangular cross-section of the outgoing rod material is such that the main axis is 1.5 - 2.5