JP5046944B2 - Method for manufacturing a metal plate from magnesium melt - Google Patents

Abstract

A method for producing metal sheets from a magnesium melt, comprises the following steps: producing the magnesium melt, casting the magnesium melt to a cast strip, immediately after casting, strip-rolling the cast strip to a rolled strip, cross-cutting the rolled strip to metal sheets, rolling the metal sheets to a final thickness, the rolling of metal sheets being carried out, in relation to the metal sheets, in a direction a at right angle to the rolling direction of the strip-rolling, said direction being maintained during the entire rolling of the metal sheets. The method according to the invention enables very wide sheets to be produced in a simple way which meet the end user's requirements.

Description

Field of Invention

  The present invention relates to a method for producing a metal plate from magnesium melt.

  Magnesium flat products are increasingly being used, especially in the field of body structures for the production of parts that are both light weight and at the same time inherently stable, as well as comparable application areas.

  The so-called “continuous casting and rolling” is an advantageous method for producing strips with a constant thickness, in which a metal melt is cast into a strip of thickness close to the final dimension and, immediately thereafter, hot Hot rolled in-line to rolled strip. The resulting cast and hot rolled strip is then further processed. In this case, an annealing process as well as other rolling processes or forming operations are also included (DE10052423C1).

  The width of the strip produced in this way is limited by the width of the rolling interval of the roll stand used in its forming. Only so-called “slit strips”, which are smaller than the width of the original product, can be separated from said strips by longitudinal cutting. However, for the user part of the flat product, there is not only a demand for the widest spectrum of the most diverse thicknesses, but also a width that fits the intended purpose for each (that is manufactured on a conventional mill train). There is also a demand for more

  Based on the above prior art, the object of the present invention consists in suggesting a simple method that allows the magnesium metal sheet to have a larger width and excellent mechanical properties to be manufactured.

The object is a method as described in the premise of the present specification, comprising the following steps:
Producing magnesium melt;
Casting the magnesium melt into a casting strip;
Immediately after casting, strip-casting the cast strip into a rolled strip;
Cross-cutting the rolled strip into a metal plate (Querteilen);
Rolling the metal plate to a final thickness;
Here, with respect to the metal plate, the metal plate is rolled in a direction perpendicular to the rolling direction of strip rolling, and the direction is maintained during the entire rolling of the metal plate;
This is achieved by a method of manufacturing a metal plate from magnesium melt.

  According to the invention, a cast strip having a constant width is first produced from magnesium melt in a known manner, limited by the machine used for rolling. Next, the plate is cut from the strip. Then, if necessary in several passes for the time, the metal sheet is rolled perpendicular to the longitudinal direction of the strip rolling, on the one hand to the desired width and on the other hand to the required thickness. Reach. In this specification, “the rolling direction of the metal plate” always means the direction in which the metal plate enters the next rolling pass. That is, immediately after being separated from the cast and rolled strip, the metal plate still arranged in the longitudinal direction of the strip rotates at right angles (eg about the axis) to the surface of the metal plate, so that the length of the strip That direction, which is originally aligned equal to the direction, is arranged at an angle to it. In this way, very wide plates that meet the requirements of the end user can be produced with a particularly simple process.

It is clear that the metal plates produced according to the invention have excellent mechanical properties and structures that are advantageous for their subsequent processing. In this case, the deviation between the characteristics determined in the longitudinal, transverse and diagonal directions of the metal plate produced according to the invention is small. Apart from the advantages of producing wide metal sheets, technical literature for rolling magnesium metal sheets using repeated orientation changes (Beck, Adolf "Magnesium und seine Legierungen", Springer B l n 2. The positive effects already described in Auflage 2001, Kapitel: Technologie des Walzens) already occur in the processing steps according to the invention. Surprisingly, in this case their arrangement between the rollings is reduced because the resulting property improvement occurs in the rolling method according to the invention, even though the metal sheet separated from the strip is moved only once. Deviate from the array of strips received.

  In order to achieve a uniform distribution of excellent mechanical properties and a particularly good ductility in the metal sheet produced according to the invention, the process according to the invention is carried out and the resulting metal sheet has little segregation. For this purpose, when the temperature of the metal plate is lower than 200 ° C., it is advantageous to heat the metal plate to the initial rolling temperature (especially higher than 200 ° C.). A typical initial rolling temperature in this case is in the range of 200 ° C to 450 ° C.

  In order to produce a particularly thin and wide metal plate, the metal plate can be rolled in several rolling passes if necessary. When using multi-pass rolling, it is advantageous in known methods to heat the metal plate to the initial rolling temperature during each rolling step.

The present invention will be described in more detail below based on the drawings showing embodiments.
It is a schematic diagram from the upper side of a manufacturing line which manufactures a wide metal plate from magnesium melt. Yield recorded in each case in the longitudinal, transverse and diagonal directions of a magnesium strip cold-rolled longitudinally in the conventional method and a magnesium strip cold-rolled perpendicularly in the method according to the invention It is a figure which shows point _Rp0.2 and tensile strength.

  The production line 1 includes a melt refining vessel (Schmelzengefaess) 2, and magnesium is fed from the melt refining vessel by a nozzle 3 to a casting slit (not shown) of a twin roll strip casting machine (Zwei-Rollen-Bandgiessmaschine) 4. Melt S is supplied.

  The strip casting machine 4 in the currently known method has two casting rollers, which are vertically arranged vertically (not shown), and horizontally continuous between them. There are limited casting slits.

  The cast magnesium strip M leaving the strip casting machine 4 is continuously transported to the roll stand 5 installed in line with the strip casting machine 4 in the post-casting operation, where the strip is, for example, thick Rolled to a 6.5 mm hot rolled strip W. The metal plate B is cut from the hot-rolled strip W leaving the roll stand 5 by a cross cutting shear 6 arranged in a line in the conveying direction F behind the roll stand 5. If necessary, the hot-rolled strip W is trimmed along its side by a trimming machine (not shown) before the cross cutting shear 6.

  The metal plate B cut off from the hot-rolled strip W has a rectangular shape when viewed from above, and the longitudinal direction side LS of the metal plate arranged in the longitudinal direction L of the magnesium strip M is: It is narrower than its transverse direction QS arranged perpendicular to the longitudinal direction L of the hot-rolled strip W. The width of the metal plate is equal to the width b of the hot strip W.

  From the cross cutting shear 6, the metal plate B reaches the transport section 7 and is picked up by the swivel arm 8 of the stacker device 9 at the end of the transport section. The swivel arm 8 is pivotably arranged about the vertical axis 10 and thus rotates 90 degrees about the vertical axis 10. In each case, the picked metal plate B is thereby rotated 90 degrees about the axis 11 normally arranged on the surface of the metal plate B.

  The stacker device 9 places the metal plate B on the stack 12. In the said position, the longitudinal direction side LS of the metal plate B is arranged at right angles to the longitudinal direction L of the hot-rolled strip W.

In each case, the conveying device 13 transports one of the stacked metal plates B to the cold rolling mill 14, so that the metal plate is initially cooled on one short longitudinal side LS1. The rolling interval (not shown) of the intermediate rolling mill 14 is entered. In this method, each metal plate B is rolled in a direction Q in which the hot-rolled strips W are arranged at right angles to the originally rolled longitudinal direction L (ie offset 90 degrees). In each case, the length is substantially larger than the width b of the hot-rolled strip W from the 6.5 mm-thick metal plate B by cold rolling six times with intermediate heating in the furnace 15. A 0.9 mm-thick metal plate Bf having LBf is finish-rolled.

  The obtained metal plate Bf is finally annealed at 330 to 360 ° C.

The final annealed finished metal plate Bf has excellent mechanical properties. Therefore, in the case of the magnesium metal plate Bf tested here, the yield point _{R p0.2} is in the range of 165~170N / mm ^2, a tensile strength _{R m} is in the range of 250~270N / mm ² and elongation rate _{a 50} ranged from 15-20%.

FIG. 2 is a diagram comparing values of R _m , R _p0.2 , and A ₅₀ for a metal plate rolled in the longitudinal and transverse _directions . Here, the values indicated by the lines represent the longitudinal rolling material, and the rectangles, black circles, and stars represent the measured values for the transverse rolling material.

1 ... Production line; 2 ... Melt refining vessel; 3 ... Nozzle;
4 ... Twin roll strip casting machine; 5 ... Roll stand;
6 ... cross cutting shear; 7 ... conveying section; 8 ... swivel arm;
9 ... Stacker device; 10 ... Vertical axis of swivel arm;
11 ... Axis on which metal plate B rotates; 12 ... Metal plate stack;
13 ... conveying device; 14 ... cold rolling mill; 15 ... furnace; B ... metal plate;
Bf: finish rolled metal sheet; b: width of hot-rolled strip W; F: transport direction;
L: longitudinal direction of the magnesium strip M;
LBf: Length of finish rolled metal plate Bf; LS: Longitudinal side of metal plate B;
LS1... Longitudinal direction where each metal plate B enters the cold rolling mill;
M ... magnesium strip; QS ... cross side of metal plate B;
S ... Magnesium melt; W ... Hot rolled strip

Claims (5)

A method for producing a metal plate (B) from magnesium melt (S), comprising the following steps:
Producing magnesium melt (S);
Casting the magnesium melt into a casting strip (M);
Immediately after casting, the cast strip (M) is strip-rolled into a rolled strip (W);
Cross cutting the rolled strip (W) into a metal plate (B);
Rolling the metal plate (B) to a final thickness;
Here, with respect to the metal plate (B), the rolling of the metal plate (B) is performed in a direction (Q) perpendicular to the rolling direction (L) of the strip rolling, and the direction is that of the metal plate (B). Shall be maintained during the entire rolling;
Said method.   The method according to claim 1, wherein the rolling of the metal plate (B) is performed in several rolling passes.   The method according to claim 1 or 2, wherein when the temperature of the metal plate is lower than 200 ° C, the metal plate (B) is heated to an initial rolling temperature.   The method according to claim 2 or 3, wherein the metal plate (B) is heated to an initial rolling temperature between each rolling step.   The method according to any one of claims 1 to 4, wherein the finish-rolled metal sheet (B) undergoes final annealing at 330C to 360C.

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