JP2010005656A - Method of manufacturing magnesium sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a magnesium sheet by which the amount of camber of the sheet is suppressed. <P>SOLUTION: In a stage for performing hot or warm rolling, a coil of the magnesium sheet which is reversely rolled or rolled and wound is rearranged on the unwinding side and a plurality of passes of rolling for supplying the sheet to the next pass are repeated without changing the upper and back surfaces to be rolled and also different circumferential speed rolling which is 1.05-1.3 in the circumferential speed ratio of the upper and lower work rolls and the relationship in the dimension of the circumferential speed between the upper and lower work rolls is reversed every next pass, is continuously performed in at least the last two or more passes. Otherwise, the coil of the rolled magnesium sheet is rearranged on the unwinding side, a plurality of passes of rolling for supplying the sheet to the next pass are repeated by changing the upper and back surfaces to be rolled every next pass are repeated and also the different circumferential speed rolling which is 1.05-1.3 in the circumferential speed ratio and by which the relationship in the dimension of the circumferential speed between the upper and lower work rolls is maintained is continuously performed in at least the last two or more passes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention, in the process of hot and warm rolling of the magnesium plate, in the reverse rolling of multiple passes and the rolling by changing the arrangement of the winding coil to the unwinding side of the winding coil, different peripheral speed rolling different in the peripheral speed of the upper and lower work rolls And a method for producing a magnesium plate simultaneously.

In general, Mg and Mg alloys are difficult-to-work materials that are not suitable for plastic working at room temperature because of their crystal structures. For this reason, all the processes in rolling and press forming are performed at a high temperature. If it is attempted to process at room temperature, it will not crack because it will crack. Therefore, in addition to the material, in some cases, the device itself contacting the material must be heated and processed. For example, in the step of hot or warm rolling a coiled Mg plate, the Mg plate is thinned by rolling a plurality of passes (see, for example, Patent Document 1).
JP 2006-144062 A

  However, when an Mg plate is manufactured by rolling a plurality of passes as described above, an upward or downward plate warpage may occur in the rolling direction. When this sheet warpage occurs, wrinkles occur on the surface of the sheet in the rolling pass and the subsequent rolling pass, and target characteristics cannot be obtained. Furthermore, the equipment is damaged and causes troubles, which becomes a major operational problem. As described above, the warpage of the plate becomes a major operational problem, and its occurrence should be completely suppressed. However, the plate warpage is caused by the complicated influence of various operational problems such as the temperature difference between the upper and lower surfaces of the Mg plate, the difference in thermal expansion of the upper and lower work rolls, the effect of the rolling reduction, and the amount of roll gap increase. appear. Further, as proposed in Patent Document 1, there is a method of controlling the shape by different circumferential speed rolling in order to flatten the shape in the sheet width direction, but multiple-pass rolling is performed with the different circumferential speed rolling alone. If this happens, warping in the longitudinal direction of the plate will be emphasized. For this reason, it is difficult to eliminate board warping.

  The present invention has been made against the background of the above circumstances, and has been made to solve the above-mentioned problems relating to the production of coiled Mg plates, eliminating the occurrence of wrinkles on the surface of the Mg plates and improving the product yield. In addition, the purpose is to suppress the warpage of the equipment to the extent that the equipment is not damaged and the operational problem does not occur.

  That is, in the method for producing a magnesium plate of the present invention, the first invention of the present invention is the reverse rolling or rolling in the step of coiling and winding the magnesium plate and performing the hot or warm rolling. Then, the rolled magnesium plate coil is repositioned on the unwinding side and rolled for the next pass without changing the upper and lower rolling surfaces, and the peripheral speed ratio of the upper and lower work rolls is 1.05. It is characterized by performing at least the last two passes continuously at different peripheral speeds in which the relationship between the peripheral speeds of the upper and lower work rolls is reversed for each subsequent pass.

  The method for producing a magnesium plate according to the second aspect of the present invention is to wind a magnesium plate in a coil shape, wind it up, and hot or warm-roll the magnesium plate coil rolled and wound up. While changing the arrangement on the unwinding side and changing the up-and-down rolling surface for each next pass to repeat the rolling for a plurality of passes, the peripheral speed ratio of the upper and lower work rolls in the rolling is 1.05 to 1.3, and It is characterized in that at least the last two passes or more are continuously performed at different peripheral speeds while maintaining the magnitude relation of the peripheral speed between the upper and lower work rolls.

  The method for manufacturing a magnesium plate according to the third aspect of the present invention is characterized in that, in the first or second aspect of the present invention, in the rolling step, a final pass to be finished is an even-numbered pass.

In the present invention, a pure magnesium plate or a magnesium alloy plate is assumed as the magnesium plate. The composition of the present invention is not particularly limited.
Moreover, in the said rolling process, hot rolling or warm rolling is made into object, and it is applicable also to the process including both hot rolling and warm rolling.

In the present invention, at the time of the rolling process, reverse rolling and rolling that is rolled and wound up are rearranged on the unwinding side and rolled for use in the next pass are included in a plurality of passes. Both of them may be included in the rolling process. A magnesium plate can be efficiently manufactured into a thin plate by these rolling.
Moreover, the last two passes or more are continuously performed by different peripheral speed rolling among the said reverse rolling or the rolling by the said arrangement change. Therefore, according to the present invention, part or all of the rolling pass by reverse rolling or changing the arrangement of the magnesium plate coil is set to different peripheral speed rolling.
In the case of different peripheral speed rolling, when the magnitude relationship between the upper and lower work rolls is made constant, the plate is reversed for each pass. When the magnitude relationship between the upper and lower work rolls changes depending on the rolling pass, the upper and lower rolling surfaces of the plate are not changed. By these, the curvature which arises in a magnesium plate by the rolling by the said arrangement change can be eliminated effectively.

Moreover, the peripheral speed ratio in different peripheral speed rolling needs 1.05-1.3. If it is less than 1.05, strong processing by different peripheral speed rolling cannot be obtained, so the effect of suppressing sheet warpage is small. As the value exceeds 1.3, the amount of residual strain of the material differs between the upper roll side and the lower roll side, so the plate warpage increases. Further, the material and the work roll slide, and the target peripheral speed ratio cannot be obtained.
Furthermore, the warp can be further improved by setting the final pass by different circumferential speed rolling to the even pass.

  As described above, according to the method for producing a magnesium plate of the present invention, the magnesium plate is coiled, wound, wound, and subjected to hot rolling or hot rolling, and reverse rolling or rolling. The rolled magnesium plate coil is rearranged on the unwinding side and subjected to rolling for the next pass in a plurality of passes, and in this rolling, the peripheral speed ratio of the upper and lower work rolls is 1.05 to 1.3, at least the last Therefore, the magnesium plate can be efficiently manufactured into a thin plate by reducing the warp to a level where there is no operational problem.

(Embodiment 1)
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
This will be described as a process in which a magnesium alloy melt having an appropriate composition is cast, and then the thickness of the product is adjusted by hot rolling and warm rolling. Further, the present invention may be a step of forming a hot-rolled sheet by continuous casting and rolling and warm-rolling it.

Hot / warm rolling This step is a step for processing an ingot or continuously cast rolled plate into a magnesium plate having a predetermined thickness. Here, rolling at 300 ° C. or higher is hot rolling, and rolling at less than 300 ° C. is warm rolling.
The outline of the rolling apparatus will be described. Rolling equipment combining work rolls 2 and 3 for rolling a plate, a reel for unwinding and winding the plate, and a device for heating and holding the plate, and control of twin motor drive Is possible. Work rolls 2 and 3 can be heated to a surface temperature of about 350 ° C. by a sheathed heater installed inside. Rolling can be performed by heating the material at a heating temperature of 300 ° C. in hot rolling and 230 ° C. in warm rolling. A device using a heating source such as a high frequency or a halogen lamp is installed in the heating device so as to control the temperature in the plate longitudinal and width directions to be constant.

  In reverse rolling, the magnesium plate 10 is fed from the unwinding coil 1 to the winding coil 5 in one pass, and rolled by work rolls 2 and 3 that rotate at the same peripheral speed. In the next pass, rolling is performed by reversing the work rolls 2 and 3 with the winding coil 5 as the winding side and the winding coil 1 as the winding side. Reverse rolling is performed by repeating this.

After the reverse rolling is performed with a predetermined number of passes, different peripheral speed rolling is performed by changing the peripheral speed between the work rolls 2 and 3 continuously for the last two passes or more. At this time, the peripheral speed ratio is in the range of 1.05 to 1.3, and the relationship between the peripheral speeds of the upper and lower work rolls 2 and 3 is reversed every next pass. That is, in the first pass of different peripheral speed rolling, for example, when the peripheral speed of the upper work roll is larger than that of the lower work roll, the relationship is reversed in the subsequent passes. It is possible to change the value of the peripheral speed ratio.
The final rolling pass is preferably a plurality of passes in the entire rolling pass. Thereby, curvature can be improved more.
Moreover, it is desirable that the number of passes of different peripheral speed rolling is an even number.

(Embodiment 2)
In the hot rolling and warm rolling processes, in addition to the reverse rolling, as shown in FIG. 2, the winding coil 5 wound by rolling is rearranged to the unwinding side using the rolling device, and the winding is performed. A magnesium plate can be unwound as the take-up coil 1 and rolled by the work rolls 2 and 3. However, in this case, when changing the arrangement, it is necessary to perform rolling so that the upper and lower rolling surfaces do not change.

  After rolling by the above-mentioned change of arrangement with a predetermined number of passes, different peripheral speed rolling is performed by changing the peripheral speed between the work rolls 2 and 3 continuously in the last two passes or more or in all of the change-over rolling. . Also in this case, the peripheral speed ratio is in the range of 1.05 to 1.3, and the relationship between the peripheral speeds of the upper and lower work rolls is reversed every next pass.

(Embodiment 3)
In the hot rolling and warm rolling processes, using the rolling device, as shown in FIG. 3, the winding coil 5 wound by rolling is rearranged to the unwinding side, and a magnesium plate is used as the winding coil 1. Rolling out can also be performed by the work rolls 2 and 3. However, in this case, when changing the arrangement, the vertical rolling surface is changed for each subsequent pass, and the next pass is used.

  After rolling by the above-mentioned change of arrangement with a predetermined number of passes, different peripheral speed rolling is performed by changing the peripheral speed between the work rolls 2 and 3 continuously in the last two passes or more or in all of the change-over rolling. . At this time, the peripheral speed ratio is set to a range of 1.05 to 1.3, and the relationship between the peripheral speeds of the upper and lower work rolls is kept constant. Therefore, the peripheral speed ratio may be different between passes.

  In Embodiment 1-3 above, an intermediate annealing step can be provided between the hot rolling step and the warm rolling step or in the middle of the warm rolling step. Examples of the conditions for the intermediate annealing include 8 to 16 hours in a temperature range of 300 to 450 ° C.

  In this test, rolling was performed with an appropriate pass schedule in rolling consisting of 5 or more total rolling passes. An AZ31 alloy sheet with a thickness of 5.4 to 6.5 mm is thinned by hot rolling to near 2.0 mm with an appropriate pass schedule, and the rolling speed is controlled by controlling the peripheral speed ratio within a specified range. It was.

First, in the method shown in Embodiment 1, in the pass schedule shown in Table 1 (test materials No. 1 to No. 8), in the range of the peripheral speed ratio of 1.0 to 1.3, in the vicinity of 2.0 mm plate thickness. To 0.6 mm to the thickness of the plate. At this time, in the different circumferential speed rolling performed continuously, the magnitude relation of the circumferential speed between the upper and lower work rolls was reversed for each pass. In addition, for comparison, a sample that was subjected only to constant speed rolling while performing reverse rolling (sample No. 10) and a sample that was subjected to different peripheral speed rolling only on the last pass (sample No. 11) were prepared. did.
Note that the path schedule in Table 1 indicates that the path and path No. The thickness in the table indicates the thickness after the pass (same for Table 2).

Next, as shown in the second embodiment, during coil rolling, the coil on the winding side is rearranged on the winding side so that the upper and lower rolling surfaces do not change with the completion of coil winding in one pass. In the continuous different peripheral speed rolling, the magnitude relationship between the upper and lower peripheral speed ratios was reversed for each pass, and rolling was performed according to the pass schedule shown in Table 2 (test material No. 20).
Further, as shown in the third embodiment, in coil rolling, when the winding of the coil in one pass is completed, the upper and lower rolling surfaces are changed so that the winding side coil is rearranged to the unwinding side, and a continuous difference is made. In the peripheral speed rolling, rolling was performed according to the pass schedule shown in Table 2 (test material No. 30) so that the relationship between the upper and lower peripheral speed ratios does not change for each pass.
Note that steepness was used to determine the flatness of the plate material. The measurement of the steepness is a value obtained from the following formula 1 (m is divided by δ) using the arc length m and the warp height δ of the plate at the plane distance 2l shown in FIG. It shows that the warpage is large.
Steepness K = m / δ Equation (1)

It is a flowchart which shows the process of one Embodiment of this invention. Similarly, it is a flowchart which shows the process of other embodiment. Similarly, it is a flowchart which shows the process of other embodiment. It is a figure which shows the measuring method of the steepness in the Example of this invention.

Explanation of symbols

1 Unwinding coil 2 Work roll 3 Work roll 5 Rewinding coil

Claims (3)

  Magnesium plate is coiled, unwound, wound up, and rolled or rolled up by changing the magnesium plate coil rolled up by reverse or rolling in the process of hot or warm rolling The rolling for the next pass is repeated a plurality of passes without changing the surface, and the peripheral speed ratio of the upper and lower work rolls in the rolling is 1.05 to 1.3, and the magnitude relationship of the peripheral speeds between the upper and lower work rolls is as follows: A method for producing a magnesium plate, characterized in that at least the last two passes are continuously performed at different peripheral speeds that are reversed for each pass.   Magnesium plate is coiled, unwound, wound, and hot or warm rolled. During rolling or rolling, the rolled and wound magnesium plate coil is rearranged on the unwinding side, and the upper and lower rolling surfaces are next. While rolling for each pass is repeated for multiple passes, the peripheral speed ratio of the upper and lower work rolls is 1.05 to 1.3 in the rolling, and the relationship between the peripheral speeds of the upper and lower work rolls is maintained. A method for producing a magnesium plate, wherein the different circumferential speed rolling is continuously performed for at least the last two passes.   3. The method for manufacturing a magnesium plate according to claim 1, wherein in the rolling step, a final pass to be finished is an even-numbered pass.

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