Split section pass forming unit

Abstract

This document describes a slotted section forming unit comprising a pair of rollers and a rib removal means, wherein the pair of rollers has a profile configured to produce a pair of slotted rods with symmetrical dimensions, said pair of slotted rods being connected by a rib, and the rib removal means for removing the rib in its entirety, forming a first slotted rod and a second slotted rod.

Description

Split section pass forming unit BACKGROUND OF THE INVENTION Field of invention The present invention relates generally to the field of wire rod rolling mills. More specifically, the present invention relates to a new split-section pass formation in a wire rod rolling mill. Analysis of the related technique Rolling a small product on a wire rod rolling mill limits the production rate (expressed in tonnes per hour, or t / h) to a level below the reheating furnace's capacity. For example, rolling 5.5 mm diameters at 115 m / s results in a production rate of approximately 70 t / h, which represents less than 50% of the capacity of a typical reheating furnace. Full utilization of the furnace capacity is generally achieved with diameters of 8.0 mm and larger. Various solutions in the prior art have been attempted to address this problem. One solution involves double-strand rolling, that is, rolling two billets in the mill simultaneously and finishing them on separate lines. The experimental use of accumulators, such as the Morgan MorShor®, is also known in the art. However, such prior art machines did not perform as expected, since the material can never be controlled with sufficient precision to make the process reliable. Other prior art solutions, such as the Danieli Twin MIDA®, are based on casting two billets simultaneously, rolling the double strand in parallel, and diverting them to separate finishing lines. These solutions create quality problems because the billet casting speed is too high for many products.Document EP 0532856 A1 describes a split-section pass forming unit comprising rolling rolls (not shown) for forming a bar with a "cloverleaf" cross-section, a splitting station comprising a roller box for transforming the "cloverleaf" cross-section into a "peanut" cross-section, and a splitting box for cutting the "peanut" cross-section bar into separate bar sections. The previous technique does not yield quality smooth round wire rod. To increase production, a rolling mill can roll two billets simultaneously and feed them to separate finishing mill lines. This limits the quality of the bar that can be produced, as the elastic deflection of the rolling mill becomes more pronounced under these loading conditions, leading to a loss of control over the section being rolled and, consequently, the final material tolerance. This poses significant challenges when it comes to balancing the temper of the individual lines and producing the same metallurgical properties in the finished material from the same steel heat. The splitting technology has existed for many years and is used for the production of deformed or ribbed construction material where, generally in the prior art, tolerance and surface quality are not of paramount importance. This technology is particularly used in bar rolling mills to produce multiple finished sections from a single line of rolled material in the roughing and intermediate mills. However, it should be noted that this process has not been transferred to wire rod rolling mills due to the inability to control the split section with sufficient precision to produce the required accuracy of the feed section and the inability to remove the required rib in a splitting feed known as a splitting pass. The embodiments of the present invention constitute an improvement over the systems and procedures of the prior art. SUMMARY OF THE INVENTION In one embodiment, the present invention provides a split-section pass forming unit comprising: a pair of rollers, the pair of rollers having a rolling profile configured to produce a pair of split bars with symmetrical dimensions in the form of symmetric rounds, said pair of split bars being connected via a rib; and a deburring means configured to completely remove the rib, forming a first split bar and a second split bar, wherein the deburring means is a punch and die process using a customized rib-removal deburring process, or wherein the deburring means uses an abrasive wheel. In another embodiment, the present invention provides a wire rod rolling mill comprising a split-section pass forming unit according to the invention. According to another embodiment of the present invention, the first and second split bars of a split section pass forming unit according to the invention can be produced on individual finishing lines or on a combined finishing line / rolling train capable of rolling two end sections simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS The present description, based on one or more different examples, is detailed with reference to the following figures. The drawings are provided for illustrative purposes only and merely represent examples of the present description. These drawings are provided to facilitate the reader's understanding of the present description and should not be considered as limiting its scope, reach, or applicability. It should be noted that, for clarity and ease of illustration, these drawings are not necessarily drawn to scale. FIG.1 shows a lack of symmetry in the split section of the previous technique. Figure 2 shows a split section according to the teachings of the present invention, demonstrating symmetry. Figures 3A to 3C show a punch and die procedure used for nerve removal. FIGS. 4A to 4B show additional nerve removal processes according to various embodiments of the present invention. FIGS.5A and 5B show different designs of the use of the wire rod rolling mill in conjunction with the present invention. DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Although this invention is illustrated and described in a preferred embodiment, it can be produced in many different configurations. A preferred embodiment is shown in the drawings and will be described in detail herein. It is understood that this description is to be regarded as an example of the principles of the invention and the associated functional specifications for its construction and is not intended to limit the invention to the illustrated embodiment. Those skilled in the art will conceive of many other possible variations within the scope of the present invention as defined by the appended claims. It should be noted that, in this description, the references to "an embodiment" or "an embodiment" mean that the feature being referenced is included in at least one embodiment of the invention. Furthermore, separate references to "an embodiment" in this description do not necessarily refer to the same embodiment; however, such embodiments are not mutually exclusive, unless otherwise stated and except where it would be obvious to those skilled in the art. Therefore, the present invention may include any variety of combinations and / or integrations of the embodiments described herein within the scope defined by the appended claims. As noted earlier, a key problem with the previous technique is the inability to remove the necessary rib in a slitting feed known as a slitting pass. If the rib is not completely removed in the case of smooth wire rod, it can laminate into the material, creating surface creases and defects that will appear in the finished product and / or cause failures in components manufactured from the wire rod. If the split section can be produced correctly and accurately, and the splitting rib can be removed, the wire rod material can be produced using a splitting process. The present invention provides a system and a procedure for removing the rib and controlling the profile to be split. The production of quality wire rod from a split section using the prior art method is not possible, in part, due to its lack of symmetry. Figure 1 illustrates this lack of symmetry in the prior art. Figure 1 also depicts the sinew 102 that is formed in the prior art, where there is no process for completely removing the sinew. A typical split section is separated by tearing in the sinew region, where the sinew is intentionally produced to tear along the dashed line shown (tearing that inevitably results in a portion of the sinew remaining in each of the split halves). The inability to completely remove the sinew (which can then become a defect in a finished smooth round wire rod) is the limiting factor of this prior art process. The present invention redefines the formation of the split section pass. Figure 2 shows a split section according to the teachings of the present invention, where the split section is almost perfectly symmetrical (compared to Figure 1) and the rib 202 has been reconfigured to allow it to become scrap material that will be completely removed in the rolling process. Symmetry is achieved by modifying the sequence of passes and the roll grooves to form symmetrical round profiles. In the present invention, a symmetrical round section can be achieved since a splitting device and a fixed knife to separate the two halves of the section are no longer required. In the prior art, the lack of symmetry was deliberately designed to allow for the operating space for the knife. In order to produce the new symmetrical section, the rolling mill groove profile is redesigned to allow for a higher fill ratio.A key aspect of this profile change is that it is only possible with the new splitting process, and the symmetrical nature of the new sections obtained after the splitting process allows the process to be used by higher quality manufacturing plants. Having a symmetrical feed to the finishing line without residual ribs ensures the production of a high-quality round bar. These round profiles can be produced on individual finishing lines or on a combined finishing line / train that can roll two finished sections simultaneously, reducing equipment costs and complexity. Nerve removal can be carried out through different procedures. In an embodiment according to the present invention, a punch and die process is employed, where a customized deburring and stripping process is provided for the complete removal of the rib. Figures 3A-C illustrate this customized process. Many of these dies are mounted on a track similar to a tank track. The track is driven at the speed of the material being deburred (Vs) and can also be driven at a slightly higher speed (Vr) to ensure that the material being processed is not impeded as it moves through the plant. Vr = Vs + a feed rate percentage of up to 3%. The dies are shaped to the section to be deburred and stripped of the rib; the upper and lower dies interact with each other to completely remove the steel rib between the two processed sections.The steel nerve that joins the two symmetrical round sections is removed, unlike the current splitting procedure, which separates the two halves by tearing the nerve and still leaving part attached or connected to the round section. In another embodiment of the present invention, the procedure employed for the complete removal of the sinew involves the use of abrasive wheel technology or cutting wheel technology, which removes the sinew entirely. Figure 4A illustrates this process. The abrasive wheel would replace the current slitting blade, which effectively separates the material by traction. It functions similarly to an abrasive wheel, as all of the sinew material is removed from the base material. In another additional embodiment not covered by the present invention, the procedure employed for the complete removal of the nerve involves the use of a high-speed cutting tool. In another embodiment not covered by the present invention, the procedure employed for the complete removal of the rib involves an arrangement of interlocked splitting rolls designed to detach the rib from the rolling process. Figure 4B illustrates this process. This procedure replicates the procedure shown in Figure 3B; however, it is incorporated directly into the roll in a rolling stand or into the rolls of a guide located downstream of a rolling stand. This procedure reduces the need for additional equipment space; however, it will require more frequent maintenance due to the reduction of the cutting and deburring surface. Figures 5A-5B show different wire rod rolling mill configurations used in conjunction with the present invention. Figure 5A shows a typical long rolling mill installation comprising a plurality of rolling stands for rolling wire rod. Typically, in this arrangement, the only product that could be produced by splitting the asymmetrical section would be a deformed bar or a deformed bar, since the previously mentioned torn rib section always remained visible in the finished plant material. However, using the present invention, the plant can now produce quality material in the same manner, quality material being that material used for structural components where the surface finish of the material's shape is an important factor.This material can now be produced at twice the rate it was previously, when the plant was limited to a single-line finishing layout. Figure 5B shows a similar layout with the addition of an extra rolling mill that can only be used for quality round wire rod products intended for the automotive industry, allowing for further improvement in the quality of the finished product. The present invention provides the ability to take a billet and produce a split section that can be cut into two acceptable feed sections and then rolled to obtain a quality round wire rod. This billet could then be fed directly from a continuous casting without slowing down the casting machine's output by rolling smaller products on the rolling line. This offers significant cost advantages for the rolling mill operator, as all products can now be manufactured as premium quality products and the billets no longer need to be sold separately. As noted earlier in the background section, the current state-of-the-art procedure results in the simultaneous rolling of multiple billets, which increases the cost of equipment and the difficulty of rolling a quality material. The advantages of the present invention over prior art processes include reduced transformation costs for the production of smaller, more profitable products. A high-grade reinforcing round steel bar (HSRB) rolling mill could be modified to produce not only deformed bar products but also quality rods in straight lengths of similar size. A constant production rate allows for the introduction and stabilization of WinLink® in the rolling process. WinLink® enables continuous or semi-continuous direct rolling of long liquid steel products without interruption. A high-speed casting machine is directly connected to a high-availability rolling mill, where the conventional billet furnace is replaced by an advanced induction unit.With lower transformation costs, significant energy savings, higher performance, smaller space requirements and lower carbon dioxide emissions, a WinLink® compact mini-steelworks can be as competitive and attractive as a larger traditional mini-steelworks. The present invention is advantageous from a business perspective because the wire rod rolling mill will always operate at an efficient speed compared to the reheating furnace. The reheating furnace could be eliminated, as the fixed production rate allows for direct casting into the rolling process. The advantages of the present invention over prior solutions are the increased production of smaller, high-quality materials, which are typically sold for higher profits; the ability to use this solution with a continuous casting rolling mill and maintain a stable casting speed for all products to be rolled; the possibility of performing the finishing roll of two high-quality round sections on the finishing mill; and the capacity to roll high-quality round material. CONCLUSION In the preceding embodiments, a system and method for the effective implementation of high-quality round wire rod production by a split-rolling process have been shown. While various preferred embodiments of the invention have been shown and described, it is understood that there is no intention to limit the invention by such description, but rather to encompass all modifications within the scope of the invention, as defined in the appended claims.

Claims

1. A split-section pass forming unit comprising: a pair of rollers, the roller pair having a roller profile comprising grooves configured to produce a pair of split rods with symmetrical dimensions in the form of symmetrical round sections, the pair of slotted rods being connected via a rib; and rib removal means configured to remove the rib entirely, forming a first split rod and a second split rod, wherein the rib removal means consists of a punch and die process using a customized deburring and rib removal process, or wherein the rib removal means uses an abrasive wheel.

2. A wire rod rolling mill comprising a split-section pass forming unit according to claim 1. 3.Use of the split section pass forming unit according to claim 1, wherein the first and second split rods are produced on separate finishing lines.

4. Use of the split section pass forming unit according to claim 1, wherein the first and second split rods are produced on a combined finishing line / train capable of rolling two finished sections simultaneously.

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