JPH0470104B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of forming a material by press.

[Prior Art] For example, when rolling down the width or thickness of a material such as a slab, conventionally the work was carried out using a rolling mill. However, since rolling mills cannot achieve a large rolling reduction per roll, several passes are required to roll down to a predetermined width or thickness, resulting in a problem of poor work efficiency.

Therefore, in order to improve work efficiency, various proposals have been made in recent years to reduce the slab by using a press that can reduce the amount of reduction per time.

[Problems to be Solved by the Invention] However, in the above-mentioned press, the press load is determined without any particular attempt to eliminate the increase in contact pressure due to friction between the material and the die.
For this reason, only customary molding can be performed,
There were problems such as increased press load.

In view of the above-mentioned circumstances, the present invention has been made with the object of making it possible to form a material with minimum press pressure.

[Means for Solving the Problems] The present invention provides a material with a parallel portion and an inclined portion extending in the parallel portion and opening away from the center in the width direction of the material as it goes rearward with respect to the feeding direction of the material. In the method of pressing and molding with a mold having
The feed amount of each pass 1 _p is calculated as the average plate width or average plate thickness.
When W _n is the plate width or thickness W on the press entrance side, W 1 is the plate width or thickness W ₁ on the press exit side, and θ is the angle of inclination of the sloped part of the mold with respect to the parallel part, 1 _p = (0.8 to 0.9) W _n - W −W ₁ /2tanθ.

[Function] In the present invention, the feed amount of each pass is set to 1/2 of the difference between the width or thickness of the plate at the entrance of the press and the width or thickness of the plate at the exit from the press, from the value obtained by multiplying the average plate width or average plate thickness by 0.8 to 0.9. Since molding is performed using the value obtained by subtracting the value obtained by multiplying the value by dividing the value by the right cut of the inclination angle of the mold slope part, pressing can be performed with the optimum load at all times.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

Figure 1 shows a general situation when a material is width-reduced by a press. In the figure, 1 is a material such as a slab, 2 is a mold for forming material 1 such as width reduction, etc. The mold 2 can be moved back and forth in the width direction of the material 1 by means of a reduction screw or a reduction cylinder. In addition, the shape of the material 1 contacting part of the mold 2 includes a parallel part 2a parallel to the material 1 and a parallel part 2a parallel to the material 1.
It has a shape with a sloped part 2b that extends from the top and gradually widens at the rear in the direction of movement of the material 1, and during molding, the sloped part 2b is parallel to the part 2a parallel to the direction of movement of the material 1.
It is now located further back.

In the above press, the press load P is generally expressed as P=K _n ·S _n ·Q _p (). Here, K _n : Deformation resistance of material 1 (Kg/mm ² ) S _n : Projected contact area of material 1 whose width is rolled down in one molding (mm ² ) Q _p : Rolling force function (dimensionless number) And the projected contact area S _n is expressed as S _n =L×t (). Here, L: Projected contact length (mm) of the material 1 rolled down in one molding t: Thickness of the material 1.

On the other hand, the magazine "Plasticity and Processing" Vo1, 11 No. 117
(October 1970), etc., theoretically, in hot pressing, the rolling force function Q _p is Q _p = 1/4 (π + L/W _n ) (L/W _n ≧ 1).
...() Q _p = 1/4 (π+W _n /L) (L/W _n <1)
...(), and it is expressed as Q _p =P _n /K _n ... (), and W _n = W + W ₁ /2 or W _n = 2W ₁ + W/3 ... (). Here, P _n ; Average contact pressure between mold 2 and material 1 (Kg/
mm ² ) W _n ; Average sheet width of material 1 (mm) W; Press entry side sheet width of material 1 (mm) W ₁ ; Press outlet side sheet width of material 1 (mm).

Therefore, as is clear from Figure 2, which shows formulas () and () as a graph, if pressure is constantly applied with Q _p ≒ 1, the average contact pressure P _n between mold 2 and material 1 will be
can be formed with a value approximately equal to the average resistance K _n of the material 1, and can be formed with the minimum pressure, so it can be said to be the most ideal press. Therefore,()
By solving this with the left side of the equation = 1, L/W _n =4-π is obtained, and from this, L≒0.86W _n . . . () is obtained. Therefore, it can be seen that the optimum projected contact length L should be approximately L≈(0.8 to 0.9) W _n for the average plate width W _n . For example, set the width reduction amount to 350mm.
(constant), if the input slab width (press input side plate width of material 1) W is 900 mm, the output side slab width (press output side plate width of material 1) W ₁ will be 550 mm,
The average plate width W _n of material 1 is W _n =
From W+W _1/2 , W _n =900+550/2=725mm, and the projected contact length L is L=0.86×8.75≒624 from formula ().
mm. Similarly, if the entrance slab width W is 1200 mm, the average plate width W _n is 1025 mm, and the projected contact length L is 882 mm.
Therefore, when the entrance slab width W is 1500 mm, the average plate width W _n is 1325 mm and the projected contact length L is 1140 mm.
A graph plotting this is shown in FIG.

Therefore, in the case of width reduction of material 1, the input side plate width W is usually determined and the width reduction amount is set, and from this, the output side plate width W ₁ and the average plate width W _n are known.
The projected contact length L may be changed so as to satisfy the equation ().

On the other hand, in the case of a simple mold 2 consisting of a parallel part _2a and an inclined part 2b as shown in FIG. If the inclination angle of 2b is θ, then the contact projection length L is expressed as L=1 _p +W-W ₁ /2tanθ... () From equations () and (), 1 _p = 0.86W _n -W −W ₁ /2tanθ ...() is found. Therefore, in each pass, the feed amount of material 1 is 1 _p
If 1 _p ≈ (0.8 to 0.9) W _n −W−W ₁ /2tanθ, good width reduction can be achieved.

Although the embodiments of the present invention have been described with respect to the case of width forming, the present invention can also be applied to thickness forming, the material is not limited to slabs, and it can be applied to various things, and other points of the present invention are explained below. Of course, various changes may be made within the scope.

[Effects of the Invention] According to the method of forming a material using a press according to the present invention, forming can be performed with the average contact pressure and the deformation resistance of the material being approximately equal, so the press load can be reduced and the feed amount can be reduced to 1 _p. Since the inclination angle θ of the mold can be easily determined to eliminate abrasion loss between the mold and the material, various excellent effects can be achieved, such as being able to perform pressing with an optimal load at all times.

[Brief explanation of the drawing]

Figure 1 is a general plan view when forming a material by press, and Figure 2 is the relationship between the rolling force function and the ratio of average plate width and projected contact length when forming as shown in Figure 1. Figure 3 is a graph showing the relationship between the average plate width, the optimal projected contact length and the entry side plate width, and Figure 4 is the feed amount for each pass when performing the press forming method of the present invention. FIG. 3 is a plan view for explaining how to make a determination. In the figure, 1 is the material, 2 is the mold, 1 _p is the feed amount of each pass, W _n is the average plate width (average plate width or average plate thickness),
W is the press entry side plate width (press entry side plate width or plate thickness), W ₁ is the press exit side plate width (press exit side plate width or plate thickness), and θ is the inclination angle.

Claims (1)

[Claims] 1. A material is pressed by a mold having a parallel portion and an inclined portion extending in the parallel portion and opening away from the center in the width direction of the material as it goes rearward with respect to the feeding direction of the material. In the forming method, the feed amount 1 _p of each pass is determined by the average plate width or average plate thickness W _n , the press entry side plate width or plate thickness W, the press exit side plate width or plate thickness W ₁ , the parallelism of the inclined part of the mold 1. A method for forming a material using a press, characterized in that, when the angle of inclination with respect to the part is θ, the forming process is performed such that 1 _p = (0.8 to 0.9) W _n −W−W ₁ /2 tan θ.