Patent Application
20130152653
The present invention relates to rolling angle profiles. More particularly this invention concerns a method of and apparatus for rolling angle iron, typically of steel.
A standard apparatus for rolling angle profiles from rolling stock has an upper horizontal profile roll and a lower horizontal profile roll that rotate about respective upper and lower horizontal and parallel axes and that together define an open roll gap or pass that lies in a rolling plane perpendicular to the travel direction of the rolling stock and that normally includes the rotation axes of the horizontal rolls. At least one nonhorizontal pair of edging rolls laterally compress the rolling stock and define a rolling plane also extending perpendicular to the travel direction of the rolling stock and perpendicular to the plane of the gap of the horizontal rolls. Such angle profiles, for example, may have equal or unequal legs, and the like.
With a so-called duo rolling method as described in U.S. Pat. No. 4,791,799 uses universal rolling stands, optionally in reverse rolling mode, used for forming a profile of the desired cross section. This system has a reversing two-high rough rolling mill, at least one universal working rolling mill and at least one flanging edge-rolling mill included in a reversing tandem rolling mill group, and a universal finishing rolling mill at the outlet end of the structural steel rolling mill. The reversing tandem group following the rough rolling mill has a universal working rolling mill, a flanging edge-rolling mill and the universal finishing rolling mill. By including the universal finishing rolling mill in the reversing tandem rolling mill group the universal finishing rolling mill also participates in the reversing action and because of that is more effective in shaping than the standard finishing rolling mill so that in practice the special universal finishing rolling mill following the reversing tandem group is omitted as well as the edge-rolling mill commonly provided with it and the roller bed located between them. The dimensional accuracy and the surface properties of the rolled product as well as the service life of the rolls of the universal finishing rolling mill are not impaired when the reduction of the universal finishing rolling mill is set smaller than that of the universal working rolling mill.
Using multiple successively arranged universal rolling stands for making double T-beam profiles is also disclosed, for example, in U.S. Pat. No. 3,251,213.
Although the use of duo or universal rolling stands for rolling angle profiles from preliminary profiles usually having square or rectangular cross sections is considered advantageous with regard to shape and dimensional accuracy of the generated angle profile, these stands with substantially horizontal work rolls are disadvantageous with regard to the flexibility of making different profiles and with regard to the number of forming gaps required for the forming process, which disadvantages result in high costs for making different angle profiles. In fact, it is typical for all methods using closed grooving that depending on the size of the angle in the angle profile, five to nine forming gaps are needed so as to generate an angle profile from a rectangular cross section.
The required gaps need a considerable roll barrel length and can only be used in limited leg thickness ranges. However, many angle profiles are made with different leg thicknesses, thereby further increasing the necessary number of gaps and thus the costs for rolls. Thus, in practice attempts were already made to improve the process of angle rolling in rolling mills in that on a duo roughing stand, a rectangular initial pass section having a small angle or a preprofiled initial pass section having a comparatively large angle is generated that then usually is formed in three cycles in the same gaps of a duo-uni-duo group until the approximate leg thickness of the finished angle is reached, and is finally formed in a separate duo finishing gap so as to obtain the finished angle dimension.
However, a disadvantage of this is that in the case of such a rolling setup, the edging stand usually designed as a simple duo stand has to be designed as a comparatively cost-intensive universal stand. Another major disadvantage of this universal rolling method is that the large, nondriven vertical rolls have to be driven by the horizontal rolls of the edging stand. For this reason it is also necessary to roll a web reduction in the edging stand resulting in thickened ends of the generated profile in the vertical roll gaps. These thickened parts are in turn also increased through the required edging for small leg thicknesses and the associated expansion of the rolling stock. Finally, with such a form of the universal rolling method it is not possible to set predetermined radii on the leg tips of the angle legs in a defined and controlled manner.
It is therefore an object of the present invention to provide an improved angle-profile rolling system.
Another object is the provision of such an improved angle-profile rolling system that overcomes the above-given disadvantages, in particular that it is possible in a simpler and improved manner in rolling trains, in reversing or continuous arrangement, to generate profiles within the tolerances and within a wide dimensional range and that have equal and unequal angle legs with optionally different thicknesses of the two legs.
A rolling apparatus for rolling angle profiles from rolling stock has according to the invention upper and lower horizontal profile rolls rotatable about respective parallel upper and lower axes and together defining an open or closed roll gap that lies in a rolling plane perpendicular to a travel direction of the rolling stock. At least one pair of nonhorizontal edging rolls laterally compress the rolling stock and define a rolling plane extending perpendicular to the travel direction of the rolling stock. The rolling plane defined by the profile rolls and the rolling plane defined by the pair of edging rolls are not coplanar with each other. This rolling stand according to the invention can do angle rolling in reversing and also continuous operating mode.
Preferably, the invention enables roll forming of leg tip radii with natural edges and also with round edges using the modified rolling apparatuses according to the invention. Angle profiles with equal and unequal legs with the same or different leg thicknesses and with leg tips having natural edges or defined round edges can be rolled by the inventive modification of the rolling apparatus with open or closed gap where, however, the essential standard stand arrangements of reversing, semicontinuous, or continuous rolling mills are used. Profiles having natural edges are to be understood as shapes that are the result of a free lateral expansion during forming without specifically influencing the shape geometry.
Preferably, the initial passes necessary for the angle size for grooving with open or closed gaps are rolled in the usual known manner from initial pass sections that have a size dimensioned for the roughing passes. These cross-sectional shapes designated as leader pass are preferably geometrically adapted in terms of their shape to the subsequent shapes; however, also preferred are methods in which the shapes are geometrically adapted to the cross sectional shape predetermined by the leader passes. Finally, this means that the open or closed gaps according to the invention can also be adapted to already existing leader pass geometries or, where applicable, can be used without any further modifications.
The vertical rolls commonly used in universal rolling stands of the prior art that are arranged in opposing pairs in the center axis of the horizontal roll and for which therefore the rolling plane defined by the work rolls is congruent with the rolling plane defined by the edging rolls, are replaced according to the invention by preferably vertically arranged edging rolls that are upstream and/or downstream of the so-called H-rolls and can preferably be fed up to the barrel region of the profile or H-rolls.
In a preferred embodiment of the invention, the edging rolls are arranged in pairs downstream of the profile rolls so that viewed in the travel direction of the rolling stock, the rolling plane defined by the at least one pair of edging rolls lies downstream of the rolling plane of the profile rolls. In an alternative and likewise preferred embodiment of the invention, the edging rolls are provided in pairs upstream of the profile rolls so that viewed in the travel direction of the rolling stock, the rolling plane defined by the at least one pair of edging rolls lies upstream of the rolling plane of the profile rolls. However, particularly preferred is a configuration in which the at least one pair of edging rolls is upstream of the profile rolls and at least one pair of edging rolls is downstream of the profile rolls, as a result of which in particular the reversing operation of the rolling apparatus according to the invention is facilitated in an advantageous manner.
However, the rolling apparatus according to the invention can also be used in continuous rolling operation without any restrictions with regard to the apparatus technology. For example, if a rolling apparatus comprising edging rolls arranged upstream and downstream of the profile rolls is used in continuous operation, then, if necessary, the pair of edging rolls upstream of the profile rolls can be permanently removed from the edge region of the angle and thus cannot influence the rolling result. Of course, the same applies analogously for the pair of edging rolls downstream of the profile rolls in the rolling direction.
It is preferred that the rolling apparatus according to the invention is mounted on a common stand base and therefore is also used as a quasimodified universal rolling stand within a rolling train. With this preferred embodiment, it is also possible to do a retrofit or replacement with the stand, or to completely replace sets of rolls.
A particular advantage of the arrangement of the edging rolls upstream and/or downstream of the roll plane of the profile rolls is that, if needed, the edging rolls can be set at a spacing from each other that is smaller than the barrel width of the profile rolls. In conventional universal roll stands, positioning the edger relative to one another was always limited by the dimensions of the work rolls, where there was no possibility to use the edging rolls for profile widths that were narrower than the barrel width of the work rolls. This problem is solved according to the invention with particularly simple means in that the usability of the rolling apparatus according to the invention is increased without the need of installing profile rolls having a narrower barrel width for narrower profiles. Thus, the rolled width can be smaller than the horizontal barrel width, as a result of which the major disadvantage of the universal gap rolling known from the prior art using a typical H-and V-rolling apparatus and a roll gap between the V-rolls and the front faces of the H-rolls is avoided.
At the same time it is now possible with the same set of rolls to roll angles having different leg lengths, this being particularly advantageously facilitated if the edging rolls can be moved relative to the rolling stock individually and also within the respective pairs of edging rolls.
The H-rolls of the stands have similarly shaped open drawing passes for reducing the thickness to the desired thickness of the finished angle. It is typical here that in all stands the barrel widths are selected large enough that even the largest leg lengths, which are design-specifically allocated to a dimension group, can be formed in the barrel region of the H-rolls.
In the meaning of the invention, the edging rolls do not have to be vertical and perpendicular to the profile rolls. Rather, also such embodiments are considered to be comprised by the inventive idea in which the edging rolls have only an inclined position of their longitudinal axes relative to the longitudinal axis of the upper or the lower profile roll, which principally results in a V-shape of the position of the pair or pairs of edging rolls relative to each other. The advantage of an inclined position of the longitudinal axes of the edging rolls is a smaller reverse bend in the finishing pass. This is in particular of advantage in the case of angles having a significant leg length.
Due to the ability of the inventive rolling apparatus to set the edging rolls in an inclined position with regard to the rolling stock, the possibility of making a great variety of profiles without the need of replacing complete apparatus portions is supported. Preferably, influencing the medium straight profile width and thus the leg lengths takes place by the vertical edging rolls that, however, are oriented at an angle. The width-dependent dimension groups are mainly determined by the possible vertical positioning range of the rolling apparatus, preferably in a modified universal rolling stand, because the edging rolls are not impaired by the H-barrel width.
The shape of the edging rolls of a rolling apparatus according to the invention is not necessarily strictly cylindrical with a round cross section, but can deviate from this shape at least over partial lengths of the edging rolls. In the meaning according to the invention, the vertical edging rolls, depending on the horizontal gap shape of the profile rolls used, are cylindrical or frustoconical if the leg ends of the angle profile to be made are desired with natural edges or undefined edge radii. However, for implementing defined leg ends having predetermined end radii, the vertically arranged edging rolls can also be stepped and can comprise a defined transition radius in the corner of the shoulder. However, the stepped edging rolls having a transition radius can preferably be used for horizontal gap shapes of the profile rolls having a horizontal and parallel position of the leg-angle profile relative to the longitudinal axis of the respective profile rolls.
The use of stepped vertically arranged edging rolls having a defined transition radius between the legs of the angle profile may require, if needed, a new previously uncommon operating mode of the profile rolls and the edging rolls. Depending on the selected shape of the profile rolls and the edging rolls, preferably, different methods and operating modes for positioning can be selected:
In general, it is to be noted that existing rolling trains comprising universal stands are characterized in terms of their structure by an alternation of universal stands and edging stands. By sufficiently dimensioning the edging stands with regard to their maximum rolling force and the maximum rolling moment, the edging stands can be integrated in the rolling process for leg thickness reduction of the angle profile. Here, due to the machine-related design with regard to the maximum rolling force and the maximum rolling torque, the universal stands do the main forming work when making the angle profile from the preliminary profile. Also, in the universal stands, in addition to the reduction of the leg thickness, the medium straight profile width is specifically adapted to the different angle dimensions.
Since each rolling apparatus according to the invention has edging rolls arranged in pairs upstream and/or downstream of the horizontal profile rolls, the use of the rolling apparatus according to the invention results in a very effective influence on the straight profile width of the angle profile, notwithstanding that in the case of small edging rolls, the maximum vertical rolling force for the usual vertical rolling with a large roll diameter and a significant barrel width can be significantly underrun.
Since the universal mill trains from the prior art usually have twice the number of universal stands compared to edging stands, according to the invention, the required width reduction is distributed over twice the number of passes compared to the conventional known universal angle rolling method. By arranging the edging rolls upstream and/or downstream of the horizontal profile rolls, there is in addition the possibility of immediately neutralizing again the lateral expansions caused by the leg thickness reduction pass. Thus, the possible number of vertical passes doubles again when using the rolling apparatus according to the invention. This has forming-related advantages, in particular when making thin leg thicknesses for which the width reductions can be kept small in a targeted manner.
The additional possibilities of configuring the edging rolls in a continuous arrangement, for example, with changing diameters or an offset arrangement upstream and/or downstream of the stand(s) carrying the horizontal profile rolls, likewise expand the flexibility when making many different angle profiles.
In a particularly preferred configuration of the invention, the rolling apparatus according to the invention is part of a rolling train that comprises at least one rolling stand having a rolling apparatus according to the invention and at least one finishing gap. Alternatively, the rolling apparatus according to the invention can also be part of a compact group or a tandem group that comprises at least one rolling apparatus according to the invention and one finishing gap as well as a pair of edging rolls arranged between the rolling apparatus and the finishing gap. Particularly preferred is in the second alternative if the compact finishing group comprises two rolling apparatuses according to the invention and one pair of edging rolls arranged between these two rolling apparatuses. Through this, applicability of the rolling apparatus according to the invention to already existing apparatus concepts while fully achieving the above-described goals is facilitated in a particularly advantageous manner.
In reversing mill trains that usually comprise a three-stand compact group including two universal stands and one edging stand are usually identical. In such a case, the second universal stand has to be used as a duo stand in order to accommodate the finishing gap. However, in the meaning of the invention this can be avoided if the edging stand (with horizontal edging rolls, so-called “edger”) is displaceable, if a sufficient barrel length is available, and if the edging stand is sufficiently dimensioned in terms of machine stability. In this case, the finishing gap can be arranged on the edging stand (edger), and the second rolling stand having the rolling apparatus according to the invention can also be used for effective rough rolling. Moreover, this additional arrangement of the finishing gap on the barrel of the edging stand enables that a two-stand rolling stand group comprising a rolling apparatus according to the invention and an edging stand (edger) can also be used for this type of angle rolling.
This is also the case if, in addition to the compact group, a separate finishing stand is available. Since in the case of large angles, setting the folding process of the legs of the angle profile into the 90° position in the finishing stand is extremely difficult, the drawing pass in the first and second rolling stands of the compact group can also be selected with different acute angle geometries. The constant folding process can then be carried out preferably completely or partially in the edging stand. By preferably using a displaceable edging unit comprising horizontal edging rolls (edger) having a sufficient barrel length, preparatory folding into the 90° position can also be prepared in a second gap on the edging stand itself. In the last cycle, preferably, the rolled profile runs idle through the second rolling stand having the rolling apparatus according to the invention, and the folding process is prepared in the roughing gap on the edger and is completed on a separate finishing stand. The advantages of this special solution are, in particular, little gap wear in the finishing gap and a more flat configuration of the rolling stands that are modified according to the invention and have open and closed gaps, thereby enabling overall a better roll utilization.
With regard to the method, the invention is implemented in that for making angle profiles, a rolling apparatus is used that comprises an upper horizontal profile roll and a lower horizontal profile roll that together define an open or closed roll gap that lies in a rolling plane perpendicular to the travel direction of the rolling stock, and at least one pair of nonhorizontal edging rolls that laterally compress the rolling stock and define a rolling plane that is perpendicular to the travel direction of the rolling stock, wherein the rolling plane defined by the at least one pair of profile rolls and the rolling plane defined by a pair of edging rolls are not congruent with each other. According to the invention, prior to and/or after the rolling pass by means of the horizontal profile rolls, the rolling stock is formed by at least one pair of nonhorizontal edging rolls.
The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:
As seen in
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| Number | Date | Country | Kind |
|---|---|---|---|
| 102011121512.7 | Dec 2011 | DE | national |
