JPS62199206A - Sizing rolling method for bar and wire rod - Google Patents

Abstract

PURPOSE:To considerably shorten the time for roll changing by forming the calibers of 8 pieces of rolls to the same shape as the shape or a circular stock or the shape having 120% arc and relief part and sizing the rolls in a 80% range of the stock diameter. CONSTITUTION:The circular stock 6 is used as the stock. The calibers 7 of 8 pieces of the rolls 1 are formed to the same shape as the shape of the stock circle or the shape having the arc of 120% diameter and the suitable relieve parts 3. The roll reduction is then selected and the sizing is executed within the range of the stock diameter of 80% of the stock diameter. The decrease of the out of roundness is made extremely less in such 4-roll rolling than in 2-roll rolling. The part shaped by the 1st pass of rolling is hardly changed in the width in the 2nd pass and therefore, the time for roll changing with respect to size changing is considerably shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for sizing and rolling rods and wires.

(Prior art) Size change in plate rolling can be easily carried out by changing the rolling reduction of the rolls, whereas size change in bar wire rolling is
It is necessary to change the role to a dedicated role each time. Therefore, the actual situation is that rolling stoppages due to size changes account for more than 10% of the total working time, and account for more than half of the causes of stoppages.

In the past, the problem caused by this was only an increase in the cost of heating furnace fuel, electricity, etc., but recently, direct rolling of rolled materials and hot charge rolling have been implemented, and it has become a serious problem that requires the entire upstream process to be stopped. It has become a thing.

A conventional technique known as a method of sizing and rolling rods and wires includes rolling by PCRM.

This is a method in which the material is rolled in the space of three skew rolls while applying diagonal rotation to the material, and because the material rotates, it is not suitable for continuous rolling. There is also the problem that spiral flow occurs in the material, and there are only examples of this method being used for round billet rolling.

Also, flat roll rolling is a similar technology, but the last few stands are caliber rolling as in the conventional method, and when changing the size series, the roll change of the coarse and intermediate stands is eliminated, so the time saving effect is However, it is not effective in the most frequent case of role reshuffling in the final 2 to 4 stands. As mentioned above, in bar rolling, there is no practical sizing rolling method, and its realization has been awaited.

(Problem to be solved by the invention) The rolling method that is currently used almost 100% of the time in bar rolling is a method in which the entire material is rolled with two rolls forming a caliber, and generally more than 10 rolls are used to roll the material. At the rolling stand, interest rate 9
The final circular shape is obtained by performing the entire stretching by alternating the 00-0 rolling method (hereinafter, this rolling method will be referred to as the 20-rule rolling method).

FIG. 8 is an explanatory view of the 20-roll rolling method, in which the round hole type used for the final roll is fully shown, and the material entering the roll 1 has a vertically elongated oval shape. A perfect circle is formed along the caliber bottom 7 from the relief 17 part 3 in the figure to obtain the desired product diameter, and ideally, an oval is rolled and filled exactly in this part, and the relief part 3 The free surface portion 5 along the gap between the 52 rolls is widened due to the widening of the material itself.
It is expected that a shape close to a perfect circle will be obtained.

Now, when considering sizing by the 20-roll rolling method, if the roll gap is reduced by one roll from a fully circular roll gap, the diameter of the caliber bottom 7 will decrease by 1 m1I, while the diameter of the relief part 3 will decrease by 1 m1. , if the relief angle 4 is 15°, the diameter will decrease by only 027 mIII, and the difference in deviation during this time will be 0.
．． It becomes 73 mN. The diameter of the free surface 50 can be adjusted by manipulating the short diameter of the entrance oval.
This radial difference of 0.73 mm is the maximum value over the entire circumference of the finished product.

The calculated value of the possible sizing range by the 20-roll rolling method, assuming a dimensional tolerance of 1JIs of ±1.5%, a total diameter difference, and a factor of 2.1, is +2.3 of the roll true circular diameter at a relief angle of 150.
%, -22%, which is extremely small and cannot withstand practical use.

(Means for solving all problems) In view of the problems related to the conventional 20-roll rolling method, the present invention
The 0-roll rolling method was adopted as the sizing rolling method. 40
It is well known that the rolling method is aimed at precision rolling and high area reduction rolling, as disclosed in, for example, JP-A-50-140354 or JP-A-58-1703. In the present invention, we focused on the property that in addition to the rolling characteristic of the 40-rule rolling method that the width spread is small, the reduction in roundness due to the rolling operation of the rolls is extremely small due to the large relief angle.

In the present invention, a circular material is sized by passing it through two four-roll rolling mills, tBJ and tBJ, which have roll angles of 450 degrees different from each other, as shown in FIG.

The structure of the present invention is that the material is a circular material 6 shown by a dashed-dotted circle in the first figure, and the caliber 7 of the eight rolls 1 is
The material is shaped to have a circular arc with a diameter of the same to 120% and an appropriate relief part 3 relative to the circle of the material, and by arbitrarily selecting the roll reduction, the material can be spread over a wide range from the material diameter to 80% of the material diameter. This allows for sizing. 11th EI (The dotted line figure in figure B1 is 4 in the same figure +A+)
This is a rolling mill 8 shaped with a 0-roll.

The roll hole pattern arrangement in the final three passes of general 40-rule rolling is corner-to-corner, but in the present invention it is round-to-round, which is a feature of the present invention.

This is a circular material that is formed by a circle two passes before the final pass, and can be made into any circular shaped product by the round hole molding in the subsequent two passes, ranging from the circular material as it is to 80 mm of the diameter of the circular material. It is also a suitable pore array for sizing.

The reason why the general roll hole arrangement has corners except for the final pass is that it can achieve a large reduction in area, has good bite into the roll, and is advantageous against twisting of the material. This is for a reason. Incidentally, in the case of a square hole type, the maximum area reduction rate per pass is theoretically 50%, whereas in the case of a round hole type, it is about 15%.

Another feature is that the diameters of the arcs provided on the eight rolls in the final two passes are all the same or 120% of the diameter of the circle of the material. In order to minimize the occurrence of deviation in diameter due to sizing and to narrow down the possible sizing range, it is best to have the same diameter as the circle of the material, but when considering the sharing of rolls, 120% Then, the sizing according to the present invention is "J".

In particular, it is undesirable to make the diameter smaller than the circle of the material because of the problem of deviation in diameter and the possibility of occurrence of folding flaws. Note that the rolling rolls in the through-through rolling line are not necessarily limited to the final 2 bus J2+ of the present invention, and the rolling method other than the 40-rule rolling method.

Now, the basis of the sizing method of the present invention is that the deterioration in roundness due to roll reduction is small, and that the width of the part rolled and shaped in the 1st pass of the 40-roll hardly changes in width in the 2nd pass and 1". Yes, Yes, Below I will explain these two points in detail.

The (Al, (Bl and tC1) diagrams in FIG. 2 show the extremely small deterioration in roundness due to roll rolling operation in comparison with the 20-roll rolling method.

As mentioned above, the maximum deviation in diameter of the finished steel due to the reduction of the rolls occurs between the caliber bottom 7 and the relief portion 6. The tC1 diagram in FIG. 2 shows the relationship between the total maximum deviation diameter difference and the release angle 4 of the roll when the roll is pressed by 1 mm. The maximum radius difference increases rapidly as the relief angle 4 decreases, so the 40-hole rolling method in which the relief angle 4 is around 67.5° is significantly lower than the 20-hole rolling method in which the relief angle 4 is around 15°. It can be seen that it shows good qualities.

FIG. 3 shows changes in the top and bottom diameter 11 and the circumferential diameter 12, which is the dimension of the relief part, when a roll having a hole shape of 80φ base circle is fully rolled down. As mentioned above, the difference between the top and bottom diameters 11 and the circumferential diameter 12 is the maximum deviation difference, and with a roll reduction of 10 mm, the maximum deviation difference is 7.3 tn in the 20-roll rolling method.
m, whereas in the 40-rule rolling method, 0-Bmm
Please thoroughly understand this.

Next, FIG. 4 shows the characteristics of a small width spread 9 in comparison with the 20-rule rolling method. The 40-rule rolling method is
It can be seen that compared to the 20-roll rolling method, it has good properties such as a smaller width spread and less influence by the specific roll diameter.

Next, the possible sizing range according to the present invention will be explained.

Figure 5 shows that the roll caliber has the same diameter as the material circle and 1
Of the 90° holding angle of the cross section of the product per 0-ru, the inner 45° (b in the figure) is the perfect circle forming part, and the both ends are 22.5° (
In the diagram, a) K is the relief part, and the relief amount is 90° (C in the figure), which is the tangent from the perfect circle, and the relief angle 4 is 67.5°.
All cases of basic hole type are shown.

In this case, the possible sizing range is calculated values of +0% and -8°2% of the roll diameter, and the maximum deviation of the diameter is 0.6%. If the diameter of the roll caliber is 120% of the diameter of the material circle, the maximum deviation in diameter within the same sizing range is JI
2.1% and 120% of the allowable limit of S are the limits of the roll diameter that can be used. Incidentally, in FIG. 5 and FIGS. 6 and 7 described below, the dot-dashed circle indicates the circular material 6, and the dotted line indicates the caliber position 9 before rolling.

Figure 6 shows the case where the relief amount is set to 105° (D in the figure) to increase the possible sizing range, and the other conditions are the same as in Figure 5.The possible sizing range at this time is the calculated value of the roll perfect circle. The tenth factor of the diameter is -17.4%, and the maximum deviation in diameter is 1.3%.
It is.

The larger the amount of relief, the more unnatural the hole shape becomes, leading to quality concerns such as wrinkles, but it is desirable to set the value as large as possible without causing any defects. Even with some safety considerations, sizing up to 10% of the roll diameter is possible.

As shown in Fig. 7, as a method to increase the possible sizing range, the angle of the perfect circle forming part of the roll hole type in the first pass is reduced (300 in Fig. 7, E in the figure), and the angle at both ends is made small. It is also possible to increase the angles of the sections (30 degrees each in FIG. 7, F in the figure).

However, in this case, in the second roll, the angle of the perfect circle forming part is large (60° in Fig. 7), the relief angle at both ends is small (15° in Fig. 7), and the maximum deviation is This has the disadvantage of being larger than the case shown in FIG. Taking these things into consideration, the maximum amount of sizing is 20% of the roll diameter.
%, that is, it is desirable to perform sizing within the range of the material diameter to 80% of the material diameter.

(Effect of the invention) This is an example of a factory that rolls products of 22-120φ.
In the 0-roll rolling method, roll rearranging of the two finishing stands was carried out approximately 100 times, but in the 40-rule rolling method of the present invention, only 9 times were required, and the roll change was carried out approximately 100 times. The total changeover time, which is the pooling of all changeover times such as roll changeovers for coarse and intermediate stands when changing trains, and roll changeovers for special sizes, has been reduced to approximately one-third of the conventional time.

This is not only a cost advantage due to an improvement in work rate, but is also extremely effective as an indispensable technology for establishing direct rolling and hot charge rolling.

[Brief explanation of drawings]

Figure 1 +AJ, FB+ is an explanatory diagram of the 40-rule rolling method of the present invention, Figure 2 (Al, (Bl is a comparative explanation of the 20-rule rolling method and 40-rule rolling method in which the roundness decreases due to roll reduction) figure,
Figure 2 (tea) is a diagram of the maximum eccentric diameter difference and clearance angle, (Figure 6 (Fig. Figure 6 is a comparative diagram of the 20-ru rolling method and 40-ru rolling method (C1 is a diagram of the circumferential diameter and top and bottom diameter, Figure 4 is a comparison diagram of the width spread characteristics of the 20-ru rolling method and the 40-ru rolling method, Figure 5 is 6 and 7 are explanatory diagrams of the possible sizing range according to the present invention, and FIG. 8 is an explanatory diagram of the conventional 20-roll rolling method. 1: Roll 2: Rolled material 3: Relief portion 4: Relief Angle 5: Free surface 6: Circular material 7: Caliber or caliber bottom 8: Rolled material shaped with a square 40-rule 9: Caliber position before rolling 11: Top and bottom diameter 12: Circumference Agent Patent attorney Tatsuo Chanoki (A) 6th) (C) Amendation (rHrφ) Procedural amendment (voluntary) May 22, 1985 ■

Claims (1)

[Claims] Rolling using two machines: a 4-roll rolling mill in which four rolls are arranged so that the extensions of the roll axes are perpendicular to each other in the same vertical plane to form a square, and a 4-roll rolling mill in which the four rolls are arranged to form a diamond shape. In the method, the material is circular, and the caliber of 8 rolls is the same to 120 mm with respect to the diameter of the circle of the material.
% of the diameter and an appropriate relief, and the material is sized within the range of the material diameter or 80% of the material diameter by arbitrarily selecting the rolling reduction of the rolls. Sizing rolling method.