JPS5827002B2 - Finish rolling method for circular cross-section rolled material - Google Patents

Description

[Detailed Description of the Invention] Conventionally, in order to improve the dimensional accuracy of the rolled steel material having a circular cross section, it is necessary to remove the tension during rolling of the steel material. Something like this is known.

The first method is to form a loop between rolling mills, and the second method is to detect tension and automatically control the rotational speed of the rolls so that a large force is not applied to the rolled material.

However, these methods basically have limitations in terms of response speed and stability in automatic control, and therefore product dimensional accuracy cannot be improved beyond a certain level.

The accuracy varies depending on the product, but it is approximately ±0.2 to 0.
It is about 4m.

In addition, there were other disadvantages such as the equipment costs being enormous and the factory space required.

Further, due to the dimensional accuracy of these products, some products required secondary processing steps.

There are quite a few products in which drawing is performed using rolled steel bars or wire rods.

On the other hand, in the conventional rolling method for circular cross-section rolled materials, the amount of reduction is large and the center distance between the rolls between the stands is large, so even if a light reduction is attempted, the rolled material will be twisted and the dimensional accuracy of the finished product will not be improved. .

In addition, various block mills such as the Morgan block mill are used for intermediate rolling and finish rolling of steel materials, but their main purpose is to increase the speed of the mill and make the mill itself more compact, so the oval hole type shaft ratio is is not small, the reduction amount is large, and the dimensional accuracy of the obtained product is about ±0.2M.

In addition, an inlet roller guide is also required in front of the circular hole die to prevent twisting of the rolled material.

The present invention advantageously solves these difficulties and provides a method for finish rolling a circular cross-section rolled material with high product dimensional accuracy.

Below are six of its characteristics.

That is, in order to realize light reduction rolling without causing twisting, the first step is to make the first stand roll horizontal, the second stand roll also horizontal, and the third stand roll vertical when rolling steel materials, etc. The idea is to use rolling mill series close to each other resulting in combinations of rolling directions such as vertical-vertical-horizontal.

Second, the rolls of the first and second stands were carved with oval grooves to increase the length of contact with the rolled material, and the rolls of the third stand were carved with circular grooves. That's true.

Thirdly, the cross-sectional shape of the material introduced into the first stand of such a finishing rolling mill row was an oval cross-sectional shape, and its size range was set as follows.

If the product size is 571 gl1 or more and less than 40 wl1, the major axis is 1.07 D+ 0.5N to 1.18 D+ 0
．． 4 often short axis 1.01 D+ 0.2vm to 1.05
D+ 0.4m, and if the finished product size is 40M or more and 200wn or less, the major axis is 1.04 D+ 1.5 to 1.1
0D+3.5 short diameter 1.01 D+ 0.2Fa to 1
．． 02 D+ 1.5w1.

However, here, D in the formula indicating the above dimension range is defined as the point between the two points where a straight line passing through the center of the hole at right angles to the roll gap center line intersects with the profile of the hole, as will be described later. is the distance.

Fourth, the dimensional range of the rolled material having an oval or similar cross-sectional shape rolled by the first stand and the second stand is as follows.

If the product size is 5 m or more and less than 40 m, the major axis is 1.
．． 0712D+0.52■ to 1.1865D+0.
45M, and its short axis is 0.985D-0.1m to 01998D
shall be.

Also, if the dimensions of the finished product are 40w1 or more and 200m4, the major axis should be 1.0412D + 1.52M to 1.1035.
D+3.65 original, and its short axis is 0.985D11m to 0.998Dm.

The oval or similar groove used to roll a rolled material with such a cross-section must also have the following characteristics:

That is, as a fifth feature, the size range of the oval or similar shaped holes arranged in the first stand and the second stand is as follows.

That is, if the dimensions of the finished product are from 5wl1 or more to less than 40m1, the width is 1.1412D+2.02 layers to 1-2565D+1°95, and the short axis is 0.985D-0.1m to 0.998Df.
Let it be i.

In addition, if the dimensions of the finished product are 40M or more and 200wl14,
Its width is 1.0912D+4.02vt;ttt to 1.1535D+6°15Wt, and the short axis is 0.9
From 85Dm to 0.998DIw.

Sixthly, a feature of the present invention is that the distance between the roll centers between the stands is extremely small.

That is, The roll center distance between the first stand and the second stand is 5.6D+400 spells As below, The roll center distance between the second stand and the third stand is 4.6 D+ 320vtytt The following shall apply.

There is no particular lower limit, but it is better to make it as narrow as possible depending on the structure of the device.

The above features of the present invention will be explained in detail below.

In this description, the dimensions of a product with a circular cross section are 511g1
From 1 to 4071a less than 1 and from 40W or more to 20
It is displayed separately at 0 m-1.

The reason for this is that it is well known that properties such as width expansion and retention of rolled material by guides change depending on the size of the finished product.

Here, the definition of the dimensions of the finished product is as follows.

In other words, the dimensions of the finished product are as shown in Figure 1.

This is the hole size when preparing the product shape with a circular or similar hole placed on the third stand. It is the distance between two points where a straight line perpendicular to the center line i intersects the hole profile.

Now, the cross section of the material used in the present invention has an oval or similar cross-sectional shape, and is made by a known method.

Here, a shape similar to an oval is a shape that has circular arcs drawn by a single R on the top and bottom with the center of the radius on a straight line perpendicular to the center of the roll gap, as shown in Figure 2.

As shown in FIG. 3, the shape has a circular arc with the center of the radius at the center of the hole shape, and a circular arc R2 inscribed in this circular arc R1 on the left and right sides.

Also, a hexabon as shown in Figure 4.

It refers to an offtabonal as shown in Figure 5. Hereinafter, all shapes will be referred to as oval shapes.

Now, the cross section of the material used in the present invention is made by a known method.

That is, it is produced by a loop control method or by rolling the residue by various block mills, or in some cases by an uncontrolled rolling method.

The major axis and minor axis of the cross-sectional shape of this material and their axial ratios are each within the ranges described below.

Here, the definitions of the major axis and minor axis of the cross-sectional shape of the material before entering the first stand and their axial ratios are as follows.

That is, as shown in FIG. 6, when the material is caught in the first stand and the direction of the cross section of the material is fixed relative to the hole shape of the first stand, it coincides with the center line i of the roll gap of the first stand. The length of the cross section of the material in the direction of a.

The length of the cross section of the material in the direction perpendicular to the binding.

Then, this length a. is the major axis, bo is the minor axis, and a
□ Let /bo be the axial ratio of the material cross section.

The range of the axial ratio is from 5 stations or more to 4071a.
For less than 1, it is 1.03 to 1.21, and the dimensions of the product are 40
From M or above to 200m1, it must be 1.02 to 1.17.

In the figure, j indicates the expected width of the rolled material.

In addition, the range of dimensions of this material must be limited as follows.

That is, if the dimensions of the finished product range from 5 cm or more to less than 40 cm, the major axis is a.

is set from 1.07D+0.5M to 1.18D+0.4m, and its short diameter is 1.07D+0.5M.

The range is from 1.01D+0.2 stations to 1.05D+0.4 stations.

In addition, if the dimensions of the finished product are 40cm or more and 200m-1, the major axis a□ should be changed from 1.04D+1.5M to 1.10D+
3.5M, short diameter.

1. The range must be 1.02D+1.5m from the oID+0.2 station.

The reason for setting these ranges is that, as mentioned above, the material has an oval shape, so that the rolled material cannot be twisted in its normal posture without a guide to maintain the posture of the rolled material, such as an entrance roller guide, in the first and second stands. By being able to roll, and keeping the amount of reduction in the finishing hole mold 1 small, and applying a small amount of reduction in the first stand and the second stand,
Since the degree of adhesion between the rolled material and the rolls is much better than with conventional guides, twisting of the rolled material on the final stand can be prevented.

Therefore, if a material exceeding the upper limit of this range is used, the reduction amount becomes large, which tends to cause subtle non-uniformity in the plastic flow of the rolled material, which tends to twist during rolling, and increases the width.
Product dimensional accuracy deteriorates.

Also, if a material below the lower limit of this range is used, the axial ratio of the cross-sectional shape of the material will be small, so the first stand and the second stand
The stand cannot prevent the torsional moment of the third stand, and the rolled material becomes more likely to twist, resulting in poor dimensional accuracy of the finished product.

Next, the conditions required for the hole shape of the second stand will be described.

First, the second stand must have an oval hole.

The reason is that the hole shape of the third stand is circular or a similar hole shape, and it is well known that the hole shape of the second stand must be oval.

Therefore, the cross-sectional shape of the rolled material rolled in the second stand is
It is limited by the number of words.

That is, in order to improve the dimensions of the product in the third stand, light reduction is necessary, and on the other hand, the hole shape of the second stand functions as an entrance guide to hold the rolled material against the third stand. must be fulfilled.

Therefore, the cross-sectional shape of the rolled material rolled on the second stand is limited as follows.

That is, the range of the axial ratio of the rolled material having an oval cross-sectional shape is as follows.

That is, if the size of the product is less than 4011g1, the axial ratio must be set from 1.09 to 1.31, and if the size of the product is 4011m or more and 2001, the axial ratio must be set from 1.05 to 21.

Note that the definition of the axial ratio of the cross section of the rolled material is as follows.

That is, as shown in Fig. 7, the length of the cross section of the rolled material rolled in the second stand in the direction parallel to the center line of the roll gap is defined as B2, and the length of the cross section of the rolled material in the direction parallel to the center line of the roll gap is defined as B2. Let b2 be the cross-sectional dimension of the rolled material, then let a2/b be the axial ratio of the rolled material.

This definition is the same for the first stand, which will be described later.

In addition, the dimensional range of the rolled material is as follows.

If the product size is 511g11 or more and less than 40M, the major diameter is 1.0712D + 0.52 to 1.1865D
+0.45M short axis 0.985D-0.9 from 0.1m
98Dm product size is 407ia or more and 200Wt has a long diameter of 1.0412D+1.52m to 1.1035D
+3.65m short axis 0.985Dm to 0.998DW
shall be.

Although the cross section of the rolled material is limited as described above, the following considerations must be taken in order to roll the rolled material without twisting.

That is, as shown in FIG. 8, it is important to make the contact length l of the hole of the second stand as long as possible.

Since it is not possible to greatly change the shape and dimensions of the cross section of the rolled material that is bitten into the second stand in order to perform a slight reduction, and the height of the hole of the second stand, in order to increase the contact length l, the curvature of the hole of the second stand must be changed. I have no choice but to make it bigger.

However, as the curvature increases, the hole shape approaches a circular shape, which deteriorates the function of the entrance guide for the third stand.

There is a range of suitable length l for twisting, that is, an oval hole type.

The range is as follows.

If the dimensions of the product are 5M or more and less than 407N1, the width of the hole should be 1.142D + 2.02M to 1.256.
5 D+ 1.95mt, short axis 0.985D-
From 0.1m to 0.998D.

Also, the product size is from 4011111 or more to 200M or less1
Then, its width is 1.0912D+4.0211m
1.1535D+6.15N residue, and the short axis is 0.
From 985DIm to 0.998DW.

The width of the oval hole shape is defined as follows.

That is, as shown in FIG. 9, the length d between two points where the oval hole profile intersects with the roll surface forming the roll gap.
is called a hole shape.

Further, the distance B2 between two points where a straight line passing through the center of the hole shape and perpendicular thereto intersects with the profile of the hole shape is called the short axis.

Note that this definition is the same for the first stand, which will be described later, with the hole shape being A1 and the short axis being B1.

Next, the hole shape of the first stand will be described.

The relationship between the hole shape of the first stand and the hole shape of the second stand is such that a slight reduction is applied to the hole shape of the second stand.

Therefore, the short diameter of the hole shape of the first stand is made slightly thicker than that of the second stand.

Furthermore, if the dimensions of the grooves are made approximately the same, a uniform rolling reduction is applied in the second stand, and twisting of the rolled material in the second stand can be prevented.

Also, the first stand has the function of being viewed as a second stand.

The first stand holds the rolled material in a predetermined position, and the second stand holds the rolled material in a predetermined position.
This is to stabilize the biting posture in the stand.

The second stand alone cannot prevent the third stand from twisting, so the first stand is always required, and the two-point support of the first and second stands prevents the rolled material on the third stand from twisting. It can be done.

Furthermore, the roll center distance between mutual stands will be described.

In order to prevent twisting of the rolled material, the distance range must be limited as follows.

That is, the roll center distance between the first and second stands is 5.6.
D+400W or less, and the roll center distance between the second and third stands is 4.6D+320m.

- In a rolling method such as the old book method, the first stand, second stand, and third stand are all subjected to a slight reduction, so the roll dimensions can be reduced, so the rolls between the stands can be easily met. This allows the center distance to be reduced.

On the other hand, although there is no lower limit to the distance, it is better to make it as narrow as the structure of the device allows.

Now, if all the above-mentioned conditions are satisfied and the well-known general continuous rolling hole design method is combined, light reduction can be achieved, the rolled material can be rolled without twisting, and the dimensional accuracy of the rolled material after rolling can be as good as the finished product. Although it varies depending on the dimensions, it can be set within ±0.1.0 to 0.2 ON.

If the pressure is light, the absolute value of the medium wave in the hole shape will be small, so the absolute error for the estimated value of the medium wave will be small.

Therefore, it is possible to accurately estimate the cross-sectional area of the steel material in the hole pattern.
Also, the absolute value of the amount of change in medium wave when tension or compression is applied can be kept small.

Furthermore, in addition to this, the advance rate is also small, making it easier to match the volume velocities and keeping tension and compression extremely small.

The effects of the present invention are as follows.

(1) Products rolled by such a method have extremely high precision, and secondary processing such as drawing can be omitted in some cases, resulting in products with extremely high added value.

(2) If this rolling equipment is installed, there is no need for complicated speed control in coarse and intermediate stages as in the past, and equipment costs can be kept low.

(3) By arranging this device at the finishing stage, there is no need for space for forming loops, etc., the mill line can be shortened, and power costs related to control during factory operation can also be saved.

(4) If a product with the same level of dimensional precision as conventional products can be made using water droplets, it is extremely easy to do so, and dimensional instrumentation equipment and the like are not required.

In addition, the dimensions of both ends of a single rolled material are much better than before, reducing the amount of cutoff and improving yield.

(5) Furthermore, since this rolling equipment is small, it can be easily installed not only in a newly established mill line from the beginning, but also in an existing mill.

In the following, the invention will be explained in more detail with reference to the drawings.

Figures 10A, 1, 2 and 1 are explanatory diagrams showing embodiments of the present invention, Figure 11 is a plan view showing an example of the configuration of a rolling mill, and Figure 1
Figure 2 shows an actual rolling mill, where A is the above-mentioned plan view and the opening is a side view.

FIG. 10 shows an embodiment of the present invention, in which the material 1 shown in FIG. Rolling with die 4 (Figure 10) Next, the width of the hole die formed by the roll 5°6 of the second horizontal stand is A2, and the short axis is B2. 7 (FIG. 10 C), then roll 8 of the third vertical stand,
A circular or similar hole shape 10 formed by 9
(Fig. 10 2).

As a result, a product 11 (shown in Figure 10) with extremely high dimensional accuracy (circularity within ±o, 0.20 W from i, depending on the product dimensions) can be obtained.

FIG. 11 is a plan view schematically showing the configuration of a rolling mill according to the present invention having the groove arrangement shown in FIG. 10, and shows an example in which the first to third stands are unitized 12.

13 is a mill motor, 14 is a transmission gear, 15 is a pass line, 16 is a first horizontal stand, 17 is a second horizontal stand, and 18 is a vertical stand.

A specific example of the apparatus used in the present invention is shown in FIG.

The rotational force obtained by the motor 13 is transmitted to the first stand 16 and the second stand 17 at a predetermined rotational speed via the reducer 14.
, and are transmitted to the rolls of the third stand 18 to rotate these rolls.

The above example shows the case where the first stand 16 is horizontal, the second stand 17 is horizontal, and the third stand 18 is vertical, but the exact same result can be obtained even if the arrangement is vertical-vertical-horizontal. is clear.

Next, examples of the present invention will be specifically described.

Example 1 A round bar of 11.0# made of carbon steel for mechanical structures (845C) was rolled using a rolling mill arrangement shown in FIG. 11.

The material method and dimensions of each hole were as follows.

Material a.

O 1st stand A.

1 Second stand A2 =1 =1 =1 =1 =1 (Unit, ytm) 2.65+0.3 1.6 ±0.3 5.45 0.98 5.4 Second stand B2 = 10.8 3 stands D=11.13 The rolling temperature is 900℃, the rolling speed is 20'/Seo
Met.

As a result, a round bar product with a dimensional accuracy of 11.0±0.1 was obtained.

Example 2 A round bar of 7071a made of carbon steel (8150) for machine structural use was rolled using the rolling mill arrangement shown in FIG.

The material dimensions and the dimensions of each hole were as follows.

(unit: unit) Material a.

=74.60±0.3bo=71.50±0.3 1st stand A1=75.15 B1=69.86 2nd stand A2=75.64 B2=69.54 3rd stand D=71.05 The rolling temperature is 800℃, and the rolling speed is 1.7'/Se.
It was C.

As a result, a round bar product with a dimensional accuracy of 70φ±0.13m was obtained.

Among these, the present invention has the above effects when rolling steel materials, but it is also applicable to buttons having other cross-sectional dimensions and other metals such as copper, lead, aluminum, etc.

[Brief explanation of the drawings] Figure 1 is an explanatory diagram of the definition of product dimensions according to the present invention;
Figures 3, 4, and 5 are explanatory diagrams of the oval cross-sectional shape, Figure 6 is an explanatory diagram of the cross-sectional shape of the material, and Figure 7 is an explanatory diagram of a rolled material similar to an oval residue tobacco pack. Figure 8 is an explanatory diagram of the contact length of an oval hole type, Figure 9 is an explanatory diagram showing the width of an oval or similar hole type, and Figures 10 A, 1, C, 2, and H are illustrations of the implementation of the present invention. 11 is a plan view showing an example of the configuration of a rolling mill; FIG. 2.3...Roll, 4...Oval hole type, 5,6...Roll, 7...Oval hole type, 8.9... ...Roll, 10...
- Hole mold, 11... Finished product, 12... Rolling machine, 13... Mill motor 14...
Shift gear, 15...Pass line, 16...
...First horizontal stand, 17...Second horizontal stand, 18...Pear-shaped stand.

Claims (1)

[Claims] 1 Three stands are used for finishing and rolling steel materials, and each roll is arranged horizontally-horizontally-vertically or vertically-horizontally as the first, second and third stands in order from the input side of the material. A method for finish rolling a circular cross-section rolled material, characterized in that the first and second stand rolls have an oval hole shape, the third stand roll has a circular hole shape, and further satisfies the following conditions. (a) When the oval cross-sectional dimension of the material to be introduced into the first stand is set to 40 mm with the diameter of the final finished product divided by 5 sections, the major axis is 1.07 D+ 0.5W to 1.18 D+ 0.
4m short axis 1.01D 10.2m~1.05D+0.4g
When m401m1<D<20011m, the major axis is 1.
04 D+1.5M~1.10 D+3.5M Minor axis 1.
01 D10.2m to 1.02 D+ 1.5R. (b) When the dimensions of the rolled material rolled by the first stand and the second stand are 5 m<:D<40 ytm, the major axis is 1.
0712D+0.52mm~1.1865D+0.45m Short diameter 0.985D-0.1m~0.998DW40 m
When <l:D<:200 ytm, the major axis is 1.04
12D+1.52m ~1.1035D+ 3.65m Short diameter 0.985Dig! ~0.998DH. (C) When the dimensions of the oval hole type of the first stand and the second stand are 511m<D<40111IIl, the width dimension is 1
．． 1412D+2.02M ~1.2565 D+ 1.95m Short diameter 0.985D-0.1W~0.998D 40Wζ
When D<200g112, width dimension 1.0912D
+4.0211IIl~1.1535D+6.15M Minor axis 0.985 Dm~0.998 Dm. (d) The roll center distance between the stands shall be 5.6D+400W or less for the first stand and the second stand, and 4.6D+320W or less for the second stand and the third stand.