RU2710824C1 - Multi-stage rolling mill for rolling unit with finishing rolling mill with inclined rolls, hot pilger rolling or automatic rolling mill type - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: present invention relates to rolling. Rolling mill (1) for hollow articles comprises support structure (3) forming bed (4) for arrangement of stands of rolling mill (10A, 10B, 15A, 15, 15B) installed in series along axis of rolling (100). Rolling mill comprises first section (41) for rolling on long mandrel and second section (42) for rolling without mandrel, located after first section (41) relative to movement direction of said hollow items. Rolling mill is also equipped with facilities for support of mandrel. According to the present invention, the first set of stands (10A, 10B) and / or the second set of stands (15A, 15, 15B) comprises at least one stand with detachable rolls, wherein the plant comprises a second inclined rolling mill to obtain a final thickness of the hollow articles, operating on a mandrel located before the first rolling mill, wherein first section (41) is configured to roll the obtained rolled hollow articles to obtain the required thickness.EFFECT: possibility of improving the surface quality of hollow articles and improving reliability of equipment.9 cl, 8 dwg

Description

FIELD OF THE INVENTION

The present invention relates to installations for rolling hollow products. More specifically, the invention relates to a multi-stand rolling mill, preferably but not exclusively intended for rolling lines, in which an inclined roll rolling mill, a hot pilgrim pipe rolling mill or an automatic mill are used as a rolling mill to obtain a final thickness.

State of the art

The prior art installation for the manufacture of stitched (or hollow) products, for example, seamless pipes. In particular, some rolling plants comprise a rolling mill for producing a final thickness (i.e., a mill with inclined rolls) for rolling on a mandrel. An example of such rolling mills is an expanding mill, in which the stitched product is rolled between two electrically driven rolls, the axes of which are usually located at an angle of 60 ° to the rolling axis, and in which rolling is performed on a mandrel inserted into the stitched product. A piercing mill, in which two inclined rolls exert an external influence on the product, and in which the product is stitched with a mandrel, is usually located in front of the pipe expansion device. Another device, the rolling mill, is located after the device for flaring pipes and is used to align the thickness of the stitched product exiting the device for flaring. The rolling mill rolls in the product using two inclined rolls and a mandrel. After the rolling mill, a furnace is usually located, for example, on fossil fuel, in which the stitched product is kept at a predetermined temperature, and then sent to a calibration mill containing a limited number of stands, usually no more than six, but their number is variable depending on the specific situation.

The installation of this type involves at least three stations (piercing mill, a device for flaring pipes and obkatny mill) "inclined" type, which interact with the stitched product approximately along a helical path. This feature has a significant impact on the quality of the rental, because this type of rolling inevitably leads to defects in the size and / or shape of the product.

Another disadvantage of the above installation is the presence of a furnace located between the rolling mill and the calibration mill. In fact, the presence of this furnace leads to a significant increase in the overall dimensions of the installation. In addition, the use of a heating furnace has a significant impact on other aspects, including the control of accumulation of pipes, the problem of excessive decarburization and / or oxidation in case of prolonged residence in the furnace, weight loss due to the formation of scale in the furnace. In general, these aspects also affect the costs associated with the design / construction / installation management, and therefore the production costs.

In connection with the foregoing, there is a need to create a new technical solution that will eliminate or at least limit the disadvantages mentioned above. Thus, the main objective of the present invention is to provide a rolling mill that can solve these problems. Within the framework of this task, the first objective of the present invention is to provide a rolling mill installed in a plant for rolling stitched products after a rolling mill of an inclined type to obtain a final thickness of products (for example, a device for expanding pipes). Another objective of the present invention is the creation of a rolling mill, which will improve the quality of the stitched product processed in the specified installation of rolling. Another objective of the present invention is to provide a reliable and simple rolling mill at a competitive price.

EP 2878389 describes a tube mill with a mandrel, consisting of two stands located after the piercing stands. The first group of stands is designed for rolling the pipe with a mandrel inside, and the second group of stands located after the first group of stands is used to extract the mandrel without rolling the pipes. In this solution, calibration at the end of the rolling mill is not performed, and since the pipe passes a single rolling on a mandrel in the rolling mill, after passing through the rolling mill, the pipe has an unsatisfactory surface quality.

Disclosure of Invention

The present invention relates to a plant for rolling hollow products, which contains a first rolling mill, consisting of a support structure, which forms a bed for stands installed sequentially along the axis of rolling, while the specified support structure contains

- the first section for continuous rolling on a long mandrel, which contains the first group of stands installed sequentially along the axis of rolling, starting from the input section of the specified installation;

- the second section for rolling without a mandrel, located after the first section, relative to the direction of movement of the hollow products, which contains the second group of stands of the rolling mill, installed in series along the axis of rolling; means for supporting the mandrel in which

- a second rolling mill is provided to obtain the final thickness of the hollow products, located in front of the first rolling mill, and in which the first section is configured to run rolled hollow products to obtain the desired thickness, and the second section is configured to calibrate the rolled hollow products to obtain the required outer diameter .

Brief Description of the Drawings

The objectives and advantages of the present invention will become apparent on the basis of the following detailed description of an example embodiment of the invention, considered together with the accompanying drawings, given solely as a non-limiting example, in which:

- in FIG. 1 shows a side view of a rolling mill in accordance with the present invention;

- in FIG. 2 shows a horizontal projection of the rolling mill shown in FIG. 1;

- in FIG. 3 and 4 respectively show a side view and a front view of the stands of a rolling mill in accordance with the present invention;

- in FIG. 5 and 6 respectively show a side view and a front view of a stand for supporting the mandrel of a rolling mill in accordance with the present invention;

- in FIG. 7 is a schematic illustration of a rolling mill in accordance with the present invention;

- in FIG. 8 shows a section along the plane VIII-VIII indicated in FIG. 1.

The implementation of the invention

With reference to the above accompanying drawings, the present invention relates to a multi-stand rolling mill 1 for stitched products (also known as hollow products). A rolling mill 1 according to the present invention can be effectively used in a rolling installation comprising an inclined type rolling mill to obtain a final thickness of a product (for example, a pipe expansion device, Assela mill, Disher mill or a planetary rolling mill), which is used as the main rolling mill stations or devices. A rolling mill 1 according to the present invention can also be used in an installation that comprises a rolling mill for hot pilgrim rolling of pipes or an automatic mill that allows stitched products of a certain thickness to be obtained. Rolling mills of the above types are known to those skilled in the art and therefore will not be described in detail. In this regard, planetary rolling mill manufactured by KOCKS under the trademark KRM ™ is known to those skilled in the art. An example of an automatic mill is a mill supplied by AETNA STANDARD under the name Automatic Mill. An example of a Discher rolling mill is the mill manufactured by AETNA STANDARD under the trademark ACCU ROLL ™.

The above list of rolling mills is provided solely as a non-limiting example. In particular, the rolling mill of the present invention can also be used in other plants that require higher surface quality and accurate dimensions than conventional systems. This requirement is met when using a rolling mill in accordance with the present invention.

In general, the rolling mill of the present invention can be effectively used in place of the rolling mill and the calibration mill, which are standard parts of the rolling mill described above.

In FIG. 1 is a side view of a rolling mill 1 in accordance with the present invention, which comprises a support structure 3 that forms a frame 4 for accommodating a group of stands arranged in series along the axis of rolling 100 (also called rolling direction 100). The said frame 4 forms the first rolling section 41 and the second rolling section 42. The latter is located after the first section 41 relative to the direction of movement of the stitched products along the direction of rolling 100.

In the first section 41, the first group of stands of the rolling mill 10A, 10B (hereinafter also referred to as the first stands 10A, 10B) are arranged sequentially along the rolling axis 100, starting from the inlet section 4A of the bed 4. In particular, the stands 10A, 10B perform continuous rolling on long mandrel 7. As described in more detail below, when the latter is inserted into the stitched product immediately after the input portion 4A relative to the axis of rolling 100. In particular, the mandrel 7 is inserted so that the end portion 7A protrudes forward relative to the front of the stitched product lia.

The second group of stands of the rolling mill 15A, 15, 15B (hereinafter referred to as the second stands 15A, 15, 15B) for rolling without a mandrel, that is, for rolling without using a mandrel inside the hollow product, are located in the second section 42. These second stands 15A, 15, 15B, thereby, are located immediately after the first stands 10A, 10B with respect to the direction of movement (indicated by the arrow, pos. 2, Fig. 1) of the stitched products along the rolling axis 100. In other words, the second stands 15A, 15, 15B are arranged sequentially immediately behind the first stands 10A, 10B. Thus, in general, the rolling mill 1 is one machine within the same supporting structure 3, in which two rolling processes are carried out sequentially: the first - on the mandrel, the second - without the mandrel in the stitched product.

In the embodiment shown in the accompanying drawings, two stands 10A, 10B are located in the first section 41, and four stands 15A, 15, 15B are located in the second section 42 for rolling without a mandrel. In any case, the number of stands in the first section 41 may be more than two. The number of stands 15 in the second section 42 may be more than four or any other (but always more than two).

In accordance with the present invention, the rolling mill 1 is provided with first means for supporting the mandrel and preferably second means for supporting the mandrel, which are located before and after the first stands 10A, 10B, respectively, when viewed in the direction 2 of movement of the stitched products. Preferably, the tools for supporting the mandrel are located on the first portion 41 and are used to support the mandrel 7 when the mandrel, not supported and not guided by the stitched product, enters the rolling mill, and when the stitched product is removed from the mandrel to perform rolling without mandrel in the second portion 42. Preferably, the first mandrel support means comprise a first mandrel support stand 112 located between the inlet portion 4A of the frame 4 and the first group of stands 10A, 10B. Preferably, the second mandrel support means also comprise a second mandrel support stand 113 located between the first stands 10A, 10B in the first section 41 and the second stands 15A, 15, 15B in the second section 42. In FIG. 5 and 6 show images of a possible embodiment of a stand for supporting a mandrel that can be used in a rolling mill 1 according to the present invention. These implementation options are known from the prior art and are already used in all rolling mills having a held mandrel.

In connection with the foregoing, it should be noted that, from the point of view of operation, the first section 41 for rolling with a mandrel and the second section 42 for rolling without a mandrel can be used instead of the rolling mill and calibration mill, respectively. In other words, the first section 41 can perform a run-in function to obtain the desired thickness, and the second section 42 a calibration function of the stitched product to obtain the required outer diameter. Thus, the rolling mill 1, corresponding to the present invention, can be effectively used instead of two mills (rolling mill and calibration mill), which will also eliminate the use of a heating furnace installed in traditional systems between these mills. In particular, in accordance with another preferred aspect, it should be noted that the first section 41 allows for “longitudinal” run-in in thickness, rather than “winding-in”, as in traditional rolling mills. Due to this, the number of defects is reduced compared to running in a helix, which can be performed using a traditional rolling mill.

In FIG. 3 and 4 show a possible embodiment of the first stands 10A, 10B and / or the second stands 15A, 15, 15B of the rolling mill 1. In this example, stands with four rolls are shown. However, in accordance with the present invention can be used stands with three rolls. In any case, in both sections 41, 42 of the rolling mill 1, each stand of the rolling mill is similar to neighboring stands from a mechanical point of view. In particular, each stand is located at an angle of 180 ° to the adjacent stand relative to the vertical axis passing through the rolling axis 100. In this regard, the first stand 15A of the second section 42 will be rotated 180 ° to the last stand 10B of the first section 41 relative to the specified vertical axis. The terms "first" and "last" are indicated taking into account the direction 2 of the movement of the stitched product in the rolling mill 1.

In all cases, the rolls of stands 10A, 10B, 15A, 15, 15B of the rolling mill are driven by drive shafts (not shown in the figures), which in turn are connected to electric motors 40. Each drive shaft can be driven independently of other drives shafts, i.e. using a functionally independent electric motor. Alternatively, and in accordance with principles known in the art, in the case of three-roll stands, it is possible to set the mechanical transmission inside the stand in such a way that all the rolls of the stand are driven by a single electric motor. In the case of four-roll stands, two adjacent rolls must be driven by the corresponding drive shafts controlled by a single electric motor.

Preferably, the first stands 10A, 10B of the first portion 41 are adjustable stands; this applies to stands in which the radial position of the rolls relative to the rolling axis 100 can be adjusted. Preferably, at least one rolling mill with adjustable rolls is included in the second section 42. According to a possible embodiment, all of the first stands 10A, 10B and the second stands 15A, 15, 15B comprise adjustable rolls. To adjust the radial position of the rolls, adjustment systems known in the art (e.g., eccentric adjustment systems) can be used. Such systems are driven by control devices built into the design of the rolling mill.

In addition, preferably, the first stands 10A, 10B and / or the second stands 15A, 15, 15B of the rolling mill 1 comprise removable rolls. This means that the rolls can be removed from the stand without having to remove and / or without opening the stand itself. Alternatively, fixed rolls can be used, for the replacement and repair of which it is necessary to open the stands.

In accordance with another aspect, the rolling mill 1 comprises a system for leveling and locking the stands in the bed 4. According to the preferred embodiment shown in the accompanying drawings, stands 10A, 10B, 112, 113 located in the first section 41 and the second section 42 are provided with at least one pair of floating fingers 71 mounted on opposite sides of the stand and on a horizontal plane 300 that extends through the rolling axis 100. The alignment system comprises at least one first pair of hydraulic cylinders 81 and a second pair of hydraulic cylinders 82 attached to the supporting structure 3 at the output section 4B of the frame 4 and the input section 4A of the frame 4, respectively. The cylinders 81 of the first pair interact with the corresponding floating finger 71 of the last stand 15B of the second section 41, and the cylinders 81 of the second pair interact with the floating finger of the first stand of the first section 41, that is, stand 112 to support the mandrel. The cylinders 81 of the first pair move the floating fingers 71 of the stand 15B of the second section 42 so as to insert them into the external frames in the adjacent stand 15 and move the floating fingers located in these frames. This action is repeated for the first stand 112 for supporting the mandrel, located next to the input section 4A of the frame 4. In particular, the fingers 71A of the first stand 112 for supporting the mandrel are inserted into the corresponding beds in the supporting structure 3. Thus, all the stands are fixed and locked in axial direction. The cylinders 82 are fixed in the supporting structure 3 at the inlet portion 4A and interact with the floating fingers 7A of the stand 112 to support the mandrel in such a way as to move them in the opposite direction, that is, to the outlet portion 4B. Thus, the floating fingers 71, 71A are disconnected from the frames with which they were previously connected so that one or more stands of the rolling mill 1 can be removed.

According to a preferred embodiment of the invention, the stands 112, 10A, 10B, 113, 15A, 15, 15B of the rolling mill 1 are equipped with an additional pair of fixed holders 73, 73A located on opposite sides of the stand, in a substantially vertical plane 302 passing through the axis rolling 100. In this configuration, the rolling mill 1 contains additional supporting (thrust?) cylinders 91, attached to the supporting structure 3 as the output section 4B of the frame 4. The cylinders 91 act on the holders 73, 73A located in the vertical glossiness 302, similar to how the above cylinders act on floating fingers located in a horizontal plane. The interaction between the cylinders 91 and stands 112, 10A, 10B, 113, 15A, 15, 15B provides only compression.

In accordance with the present invention, as shown in FIG. 2, 7 and 8, the rolling mill 1 in accordance with the present invention is preferably equipped with a mill stand changing apparatus for introducing and subsequently removing the stands 112, 10A, 10B, 113, 15A, 15, 15B of the two sections 41 and 42. In this regard in FIG. 8 is a cross-sectional view illustrating the structure of the supporting structure 3 of the rolling mill 1, in which the frame 4 is formed between the supporting plane 101, in which the stands 112, 10A, 10B, 113, 15A, 15, 15B, and the original plane 102, essentially parallel to the reference plane, and located at a height exceeding the height of the stands. The cage changer comprises a first platform 601 on the loading side 3A and a second platform 602 on the unloading side 3B. The first platform 601 is configured to transport free stands (a general image of which is shown in pos. 9), and the second platform is configured to transport stands for replacement. The installation also includes a device for transverse translational movement 650, which pushes one or more free stands 9 located on the first platform 601, in the direction opposite to the direction of the respective stands for replacement (in frame 4) until the latter are displaced (in direction 105, perpendicular to the rolling axis 100) on the second platform 602. Two platforms 601, 602 are driven by means of supply 670 in a direction parallel to the rolling axis, as shown by arrows, pos. 8, in FIG. 2.

With reference to FIG. 7, in accordance with another aspect of the present invention, the rolling mill 1 is provided with means for supporting the mandrel 7 (not shown) for supporting the mandrel during the rolling of the stitched product in the first portion 41. In particular, the means for supporting the mandrel can be made to hold mandrel, stopped during the rolling process, or alternatively, moving it to a predetermined position. Indeed, to ensure the necessary rolling conditions, when the front part of the stitched product reaches the central plane 200 of the last stand 10B of the first section 41, the end part 7A of the mandrel 7 should protrude relative to the plane itself. When, on the contrary, the rear part of the stitched product reaches the central plane 200, the end part 7A of the mandrel should be in the input section (plane 205 in Fig. 7) of the first stand 15A of the second section 42. Thus, the means for supporting the mandrel are arranged to move the mandrel 7 in order to ensure the above rolling conditions. In this regard, it should be noted that in the rolling mill 1 in accordance with the present invention, the rolling speed is restrained (in the order of 0.1-0.3 m / s). Therefore, in order to limit the heating of the mandrel during the rolling of the first section, the stitched products obtained after the rolling mill 1, usually has one length, that is, a length of the order of 6-15 m

The present invention, therefore, also relates to a rolling installation consisting of at least one rolling mill to obtain a final thickness of the products and an additional rolling mill having the above features. As indicated above, the rolling mill 1 in accordance with the present invention is capable of continuous rolling on a long mandrel and rolling without a mandrel in stitched products, the thickness of which has already been determined using a rolling mill to obtain a final thickness. The latter can be of an inclined type, for example, a tube flaring device, an Assel mill, a Disher mill, or a planetary rolling mill. Alternatively, the rolling mill for obtaining the final thickness of the products may be an automatic mill or a hot pilgrim pipe rolling mill.

The rolling process using a rolling mill in accordance with the present invention will now be described using the example of the circuit shown in FIG. 7. The rolling mill preferably comprises a station 6 for cooling and lubricating said mandrel 7 used in the first rolling section 41 of the rolling mill 1. At the end of the rolling in the first section 41, the mandrel 7 moves back parallel to the rolling axis 100 until it reaches the initial position A, as shown in FIG. 7. Gradually, the mandrel 7 is shifted upward in the transverse direction indicated by arrow 105 to a second predetermined position B in the station 6. In this position, the mandrel 7 is cooled. Gradually, the mandrel 7 extends parallel to the axis of rolling 100 to a third predetermined position C, in which it is lubricated. After complete lubrication, the mandrel 7 returns to the second preset position B, and then to the first preset position A. From this position, the mandrel 7 extends along the rolling direction and is inserted into the stitched product loaded into the rolling mill 1. For this, the stitched product is located on the rolling axis 100 starting from the side opposite to the side on which said station 6 is located.

Rolling mill 1 in accordance with the present invention allows you to perform specified tasks and goals. In particular, the configuration of the rolling mill allows you to limit the size and cost of the installation, and also allows you to not use a heating furnace. However, the rolling mill in accordance with the present invention allows to obtain products with fewer defects than products that can currently be obtained using traditional systems, for example, consisting of a rolling mill of an inclined type to obtain the final thickness of the products.

Claims (15)

1. Installation for rolling hollow products, containing the first rolling mill (1), consisting of a support structure (3), which forms a frame (4) for stands (10A, 10B, 15A, 15, 15B), installed in series along the axis of rolling ( 100), while the specified supporting structure (3) contains the first section (41) for continuous rolling on a long mandrel (7), which contains the first group of stands (10A, 10B) installed sequentially along the axis of rolling (100), starting from the input section (4A) of the specified supporting structure (3); the second section (42) for rolling without an inner mandrel, located after the first section (41) relative to the direction of movement (2) of the hollow products, and which contains a second group of stands of the rolling mill (15A, 15, 15B) installed in series along the axis of rolling (100 ) made with the possibility of calibrating the outer diameter of the obtained rolled hollow products; means for supporting the mandrel (112, 113) for mounting the mandrel (7), characterized in that the first group of stands (10A, 10B) and / or the second group of stands (15A, 15, 15B) contains at least one stand with removable rolls, and the installation contains a second inclined rolling mill to obtain the final thickness of the hollow products, working on a mandrel located in front of the first rolling mill moreover, the first section (41) is made with the possibility of running in the obtained rolled hollow products to obtain the desired thickness. 2. Installation according to claim 1, in which the first rolling mill (1) contains first means for supporting the mandrel (112) in front of the specified first group of stands (10A, 10B) relative to the indicated direction of movement of the hollow products and / or second means for supporting the mandrel ( 113) located after said first group of stands (10A, 10B) with respect to the direction of movement (2) of the hollow articles. 3. Installation according to claim 1 or 2, in which the first means for supporting the mandrel provide a supporting mandrel stand (112) located between the specified input section (4A) of the bed (4) and the first group of stands (10). 4. Installation according to claim 2 or 3, in which the second means for supporting the mandrel provide a supporting mandrel stand (113) located between the first group of stands (10A, 10B) and the second group of stands (15A, 15, 15B). 5. Installation according to any one of paragraphs. 1-4, in which each stand (10) of the specified first section (41) contains rolls (11, 12, 13, 14), the radial position of which is adjusted relative to the axis of rolling (100). 6. Installation according to any one of paragraphs. 1-5, in which the second group of stands (15) of the second section (42) contains at least one stand with rolls (11, 12, 13, 14), the radial position of which is adjusted relative to the axis of rolling (100). 7. Installation according to any one of paragraphs. 1-6, in which the first rolling mill (1) contains means for aligning and locking these stands in the frame (4). 8. The installation according to claim 1, wherein said inclined rolling mill is a mill according to the type of pipe expanding mill, Assel mill, Disher mill, or planetary rolling mill. 9. Installation according to claim 8, which contains a station (6) for cooling and lubricating the mandrel (7) used in the first rolling mill (1).

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