JP2971308B2 - Roll cross rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll cloth rolling method, and more particularly to a roll cloth rolling method for eliminating the directionality of mechanical properties of a rolled steel sheet.

[0002]

2. Description of the Related Art In cold rolling of steel sheets, parallel roll rolling mills such as a quadruple roll type, a six roll type, and a cluster roll type are used. In this rolling, since the metal flow in the rolling process is constant in the rolling direction, it is known that the mechanical properties of the rolled material become directional as the rolling ratio increases.

[0003]

When a rolled steel sheet having the above-described directionality is used as a material, as shown in FIGS. 7A and 7B, a circular plate 01 is cut out and deep drawn into a three-dimensional mold 02. In such processing, a wave-like ear 03 occurs at the end of the processed plate 01. Since the ears 03 are cut off with a line 04 or the like to be removed to obtain a product, a portion shown by hatching in the drawing is wasted and the yield is reduced.

[0004] As a property representing the deep drawability of the above-mentioned rolled steel sheet, there is a Rankford value usually called an r value, and the larger this value is, the better the deep drawability is, that is, it is considered that ears and wrinkles do not occur. I have. Further, if the r-value has directionality, the above-mentioned ear is generated, and the yield is reduced. The present invention has been made in view of the above prior art, and has as its object to provide a roll cloth rolling method in which the deep drawability of a rolled steel sheet, particularly the directionality thereof, is improved.

[0005]

In order to achieve the above object, the present invention provides a cold rolling method using a roll cross rolling mill in which at least the upper and lower work roll axes intersect in a plane parallel to a rolling surface. Rolling so that the thrust force generated between the roll and the metal material (the force generated in the work roll axis direction) is 5% or less of the rolling reaction force. In other words, the thrust coefficient μ _T = thrust force F _T /
Rolling is performed at _a roll roughness _Ra and a roll cross angle θ ° within a range in which a rolling condition of a roll rolling force P ≧ 0.05 can be maintained.

[0006]

As shown in FIGS. 2A and 2B, when the upper and lower work rolls 1 and 2 are rolled so as to intersect in a plane parallel to the rolling surface, the work rolls 1 and 2 and the rolled steel plate 3 are interposed. , A thrust force F _T is generated. The thrust force F _T is a force acting in the work roll axial direction, and acts in the up and down directions as shown by the solid and broken lines in the drawing. Due to this thrust force F _T , the rolled steel sheet 3 is deformed not only in the rolling direction but also in the width direction, that is, sheared, and as a result, the internal structure of the rolled steel sheet 3 loses its directivity, and the mechanical strength of the rolled steel sheet 3 decreases. Properties are obtained.

In the present invention, as shown in FIG. 1, test pieces in the length direction, width direction and 45 ° direction are cut out from a steel sheet rolled at _a constant cross angle θ while changing the roll roughness Ra. the r value and the thrust coefficient mu _T of the test piece was measured quantitatively grasp the relationship between the variation Δr and thrust coefficient mu _T of r values for the roll roughness R _a, similarly cross at a constant roll roughness R _a From the steel plate rolled by changing the angle θ, cut out each test piece in the length direction, width direction and 45 ° direction, measure the r value and thrust coefficient μ _T of each test piece, and calculate the thrust coefficient μ _T
Quantitatively grasp the relationship between the cross angle θ relative to, in the thrust coefficient mu _T region which has the effect of reducing the variation of the r value [Delta] r, the roll roughness R _a corresponding to a specific thrust coefficient mu _T
And the cross angle θ can be read.

As a result, it has been found that the thrust coefficient μ _T region effective for improving the deep drawability of the rolled steel sheet and eliminating the directionality of the mechanical properties is a thrust coefficient μ _T ≧ 0.05 (FIG. 3 ( a) (b) refer), to identify the thrust coefficient μ must roll roughness corresponding to _T R _a and cross angle θ be selected at this condition, deep drawability good, moreover, to eliminate the directional rolling It was possible to do.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. FIG. 1 shows an embodiment of the present invention. FIG. 1 shows the situation of test rolling. As shown in the drawing, in the rolling mill, a pair of upper and lower work rolls 1 and 2 are arranged crossing each other in a plane parallel to the rolled steel plate 3. The roll cross angle of the work rolls 1 and 2 is θ °.

As shown in FIGS. 2A and 2B, the thrust force F _T generated between the upper and lower work rolls 1 and 2 and the rolled steel plate 3 is a force acting in the work roll axial direction. Acts vertically in opposite directions as indicated by the solid and broken lines.
Due to this thrust force F _T , the rolled steel sheet 3 is deformed not only in the rolling direction but also in the width direction, that is, sheared, and as a result, the internal structure of the rolled steel sheet 3 loses its directivity, and the mechanical strength of the rolled steel sheet 3 decreases. Properties are obtained.

From the rolled steel plate 3, three test pieces are cut out in different directions. The test piece was a test piece cut out at an angle of 0 ° to the length direction, and an angle of 45 ° to the length direction.
And a test piece cut out at an angle of 90 ° with respect to the length direction. Each r value is r ₀ ,
r ₄₅ and r ₉₀ . The average value of the r values, the variation of the r values, and the thrust coefficient of the three test pieces are obtained by the following equations.

[0012]

(Equation 1)

Here, F _T is a thrust force, and P is a roll reduction force. Here, in the test rolling mill shown in FIG. 1, the roll cross angle of a pair of upper and lower work rolls 1 and 2 is represented by θ =
Test rolling was performed using _a roll fixed at 1.3 ° and the roll roughness _Ra was changed, and the r values r ₀ , r ₄₅ , and r ₉₀ of each cut test piece were measured, and the r was measured. the equation from the value, obtains the variation Δr of the r value by the equation from the thrust force F _T and the roll rolling force P during rolling of each specimen were determined thrust coefficient mu _T. The test result is shown in FIG.
(B).

[0014] FIG. 3 (a), and the thrust coefficient mu _T and the vertical axis is a plot on a graph of roll roughness R _a and the horizontal axis, and FIG. (B), the variation of the r value Δr Is plotted on a graph with the vertical axis as the vertical axis and the roll roughness _Ra as the horizontal axis. From the results shown in FIGS. 3A and 3B,
And variation of the r value Δr for the roll roughness R _a, the relationship between the thrust coefficient mu _T is read quantitatively. Therefore,
Thrust coefficient μ _T is 0.05 or more, that is, roll roughness _Ra
Is 0.5 μm or more, it was confirmed that the variation Δr of the r value was reduced and the mechanical properties of the rolled steel sheet 3 were reduced.

Further, in the test rolling mill shown in FIG. 1, the roll roughness was limited to _Ra = 1.5 μm, and test rolling was performed using rolls having a changed roll cross angle θ. R ₀ , r ₄₅ , r ₉₀ which are r values of
From the r value, the average value of the r value and the variation Δr of the r value were obtained by the formula and the formula. Figure 4 shows the test results.
(A) and (b).

FIG. 4A shows the average value of r values as the vertical axis,
The graph is plotted on a graph with the roll cross angle θ as the horizontal axis, and FIG. 2B is plotted on a graph with the r-value variation Δr as the vertical axis and the roll cross angle as the horizontal axis. is there. From the results shown in FIGS. 4A and 4B, the relationship between the average value of the r value with respect to the roll cross angle θ and the variation Δr of the r value is quantitatively read. Therefore, when the roll cross angle is θ = 0.5 ° or more, the variation Δr of the r value
It was confirmed that the mechanical properties of the rolled steel sheet 3 decreased, and that the average value of the r value increased to improve the deep drawability.

FIGS. 5 (a), 5 (b) and 5 (c) show the thrust coefficient μ _T as a common vertical axis, and a variation Δr of r value,
Roll cross angle theta, are those obtained by arranging a graph with the horizontal axis respectively roll roughness R _a, with respect to the thrust coefficient mu _T, the variation of the r value [Delta] r, the roll cross angle theta, the tendency of the roll roughness R _a This is shown in comparison. From the results of FIG. 5, the variation Δr of the r value is expressed by the following equation: Thrust coefficient μ _T ≧ 0.0
5 decreases in a region (indicated by hatched) is improved directionality of the rolled steel plate 3 of the deep drawability is improved, and the roll cross angle θ should retain the same area, numerical area of the roll roughness R _a Becomes clear. In other words, the thrust coefficient μ _T is 0.0
In the 5 or a region, when setting a certain thrust coefficient mu _T, and θ roll cross angle required to hold the thrust coefficient mu _T, so that it can advance combination set the roll roughness R _a Become.

The present invention, light of the above-described conditions, the cold rolling using a roll cross rolling mill, to the extent that the thrust coefficient mu _T is 0.05 or more, the roll roughness under a range capable of holding the area Rolling is performed at _a degree _Ra and a roll cross angle θ. Therefore, according to the present invention, it is possible to accurately roll a rolled steel sheet having a small directional property and a good deep drawability, in which the variation Δr of the r value is reduced.

Next, FIG. 6 shows a configuration example of an apparatus applied to the above-described method of the present invention. As shown in FIG. 6, a pair of upper and lower work rolls 1 and 2 are crossed in a plane parallel to the rolling steel plate 3, the roll roughness R _a thrust coefficient mu _T is 0.05 or more shown in FIG. 5 Is predetermined in the roll roughness area that holds the area where Backup roll 1
Reference numerals 1 and 12 are provided to support the work rolls 1 and 2, respectively. The roll cross device 13 is a device that crosses the work rolls 1 and 2 and the backup rolls 11 and 12 in pairs, and is driven by a command from the control device 17.

The roll reduction device 14 is a device for applying a predetermined roll reduction force P to the work rolls 1 and 2 and the backup rolls 11 and 12. Rolling force detector 1
Reference numeral 5 denotes a device for detecting a roll rolling force P, which is attached to the roll rolling device 14. Thrust force detector 16
Is a device for detecting the thrust force F _T that occur in the axial direction of the work rolls 1 and 2, are attached to the chock of the work roll 1 and 2.

The control device 17 controls the roll cloth device 1 based on the detected roll pressure P and thrust force F _T.
8 is controlled. That is, the control device 17 includes a calculation unit 18 that calculates a thrust coefficient μ _T from the roll reduction force P detected by the reduction force detector 15 and the thrust force F _T detected by the thrust force detector 16, Part 1
The thrust coefficient μ _T calculated by using the set value (0.0
5) A check unit 19 for determining whether or not the above is satisfied, and a control unit 20 for calculating and selecting a required roll cross angle θ from the result of the check unit 19 and operating the roll cross device 13.

[0022] As described above, in this apparatus, thrust using work rolls 1 and 2, previously manufactured in roll roughness R _a region for holding a region thrust coefficient mu _T is 0.05 or more, is detected from the coefficient mu _T, since holding the automatic selection roll cross angle θ necessary to roll cross angle θ in the region corresponding to the roll roughness R _a, the direction of the mechanical properties of the steel sheet to be cold rolled It is possible to roll a steel sheet having a reduced depth and good deep drawability. The present invention can be applied not only to a 2Hi mill in which a pair of work rolls are crossed but also to any multiple rolling mill such as a quadruple and a six-ply.

[0023]

As described above, according to the present invention, when performing roll cross rolling in which a metal material is rolled by intersecting at least the axes of the upper and lower work rolls in a plane parallel to the rolling surface, the work roll and the metal are rolled. Since the thrust force generated between the steel sheet and the material is 5% or more of the rolling reaction force, the directionality of the mechanical properties of the steel sheet to be cold-rolled is reduced, and the steel sheet with good deep drawability can be reliably rolled. It works and is extremely beneficial.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an experimental apparatus used in the present invention and a procedure for collecting test pieces.

FIG. 2 is an explanatory diagram showing a relationship between a deformation direction of a rolled steel sheet and roll thrust force in roll cross rolling.

FIG. 3 shows that the roll cross angle θ is kept constant and the roll roughness R
For each test piece rolled steel plate by changing the _a, it is a graph comparing the variation Δr of the r value, and a thrust coefficient mu _T.

[4] keep the roll roughness R _a constant, each test piece of rolled steel plate by changing the roll cross angle theta, and variations in the r values [Delta] r, it is a graph comparing thrust coefficient mu _T.

[Figure 5] and the thrust coefficient mu _T common longitudinal axis, and the variation Δr of the r value, the roll cross angle theta, is a graph comparing the change in the roll roughness R _a.

FIG. 6 is a schematic diagram showing a configuration of an embodiment of a rolling apparatus to which the method of the present invention is applied.

FIG. 7 is a perspective view showing a state of a waveform ear which is conventionally generated during deep drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Work roll 2 Work roll 3 Rolled steel plate 11 Backup roll 12 Backup roll 13 Roll cross device 14 Roll reduction device 15 Reduction force detector 16 Thrust force detector 17 Control device 18 Operation unit 19 Check unit 20 Control unit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hideaki Furumoto 4-6-22 Kannonshinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Research Institute (56) References JP-A-59-215201 (JP, A JP-A-3-291101 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21B 1/22

Claims (1)

(57) [Claims] 1. A thrust force generated between a work roll and the metal material when performing roll cross rolling in which a metal material is rolled by intersecting at least axes of upper and lower work rolls in a plane parallel to a rolling surface. Roll cross-rolling, characterized in that the rolling is performed so as to be 5% or more of the rolling reaction force.