JP3403946B2 - Guide roller between stands of 4-roll rolling mill - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stand for a four-roll rolling mill which prevents twisting of a rolled material during the second pass rolling by a guide roller between stands of the four-roll rolling mill. It relates to the shape of the guide roller. 2. Description of the Related Art Generally, in the rolling of steel bars and wire rods, a method in which a four-roll rolling mill is installed in the final stage of a finishing rolling mill row or in the base material rolling to the final stage is disclosed in, for example, JP-A-6-2622.
01, JP-A-6-262202, and Japanese Patent Application No. 8
-300608. FIG. 3A is a diagram showing a four-roll rolling process, and FIGS. 3B and 3C are views of a first-pass stand 1 and a second-pass stand 2 as viewed from a rolling material entering direction. is there. As shown in FIG.
As shown in (b) and (c), the four-roll rolling mill is configured by arranging two stands with a 45 ° offset from each other in series, and a roller is provided between the stands to prevent twisting of the rolled material. An expression guide box 3 may be installed. [0003] In the above-mentioned guide roller between the stands of the four-roll rolling mill, the rolled material in the first pass is twisted in order to prevent the generation of harmful flaws (calibur spills) on the quality. And a binding force that can be supplied in the second pass is required. FIG. 4 shows a state in which the rolled material is held by a guide roller. FIG. 5 is an enlarged view of the first pass roll caliber, and FIG.
5B shows a worn state during use, and FIG. 5C shows a state in which the guide roller holds the rolled material in the worn state.
As shown in FIG. 4, a conventional guide roller 4 is a rolled material 5.
The V-shaped angle 6 of the contact portion with the rolled material is
It is in line with the use caliber shape of the pass eye. [0004] However, as shown in FIG.
As the shape of the rolled material changes as needed along with the progress of the wear portion 9 of the caliber 8 of the pass roll 7, FIG.
As shown in the figure, the contact with the guide roller becomes a point. Since the caliber wear is remarkable at the so-called shoulder portion (relatively the side of the caliber), the rolled material 10 formed by the worn caliber swells near the corner. Therefore, the contact point with the guide roller shifts to the V-shaped valley side, and the restraining force against the torsional moment decreases. As a countermeasure, it is known that a double guide roller is effective in preventing torsion with a two-roll rolling mill or the like, but there is a problem that a four-roll rolling mill has no mounting space. [0005] On the other hand, there is an example of using a carbide material or the like as a measure against roll abrasion. However, the cost of the grinding wheel becomes large. In addition, general ductile rolls have problems such as low purchase price and low grinding cost but severe wear. [0006] In order to solve the above-mentioned problems, the present invention reduces the V-shaped angle of the guide roller so as to move the passing material to the center point of the caliber.
By holding at four corresponding points to secure the restraining force against the twisting moment, the contact position is kept constant even when the shape of the passing material changes due to roll wear, and the twisting is prevented. The gist of the invention is that, in a four-roll rolling mill for bar and wire rod rolling, the contact portion of the rolled material of the guide roller between stands is reduced by one pass in the passing material .
4 points corresponding to the caliber center point of each roll
The Rukoto contacting, in the first pass 4 rolling mill stands between the guide rollers of which were characterized by not also impair the torsion binding on the change of the rolled material shape due to wear of the roll caliber. Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows a rolled material holding state when the V-shaped angle of the guide roller is reduced. As shown in this figure, the guide roller 11 having the reduced V-shaped angle 6 and the rolled material 5 make four-point contact at the upper , lower, left and right contact portions 12 of the rolled material 5 to secure the same holding force as the conventional surface contact. I do. FIG.
Indicates a state in which the rolled material rolled by the worn first pass roll caliber is held. Regardless of caliber wear, the four-point contact of the upper , lower, left and right contact portions 12 remains the same as in the case of no wear, indicating that a strong holding force against torsion can be secured. [0008] According to the shape of the first pass roll caliber, the V-shaped angle is 9 for the passing material having a corner angle of 109 °.
Use a 0 ° guide roller. Further, the effect is increased by increasing the bottom R of the guide roller V to 3 mm. When rolling bar steel with a cross-sectional area of about 180 square millimeters using a 4-roll rolling mill using a conventional guide roller, twisting of about 45 ° occurs at a rolling amount of about 50 tons, and the first pass rolling is performed. When the upper , lower, left and right contact portions of the material enter the caliber portion of the second pass, caliber spills (so-called ear flaws) occur during the second pass rolling, and the roundness deteriorates. However, when the guide roller of the present invention is used, good rolling can be performed without twisting of the rolled material even at a rolling of about 200 tons within the range of the roll reduction adjustment in the first pass. As described above, the present invention does not require any modification to the rolling mill and the guide roller mounting structure, and only changes the V-shaped angle of the guide roller to reduce the distance between the stands when the roll caliber is worn. To prevent twisting. As a result, in rolling of relatively small diameter steel bars and wire rods with high torsion frequency, stable quality can be ensured with low-cost ductile rolls.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a state in which an improved guide roller according to the present invention holds a rolled material. FIG. 2 is a view showing a state in which an improved guide roller according to the present invention holds a rolled material. FIG. 3 is a diagram showing an arrangement of a four-roll rolling mill. FIG. 4 is a view showing a state in which a conventional guide roller holds a rolled material. FIG. 5 is a view showing wear of a roll caliber. [Description of Signs] 1 First pass stand 2 Second pass stand 3 Roller guide box 4 Conventional guide roller 5 Rolled material 6 V-shaped angle 7 First pass roll 8 Caliber 9 Wear part 10 Rolled material 11 with worn caliber 11 guide roller 12 having a smaller V-angle vertical and horizontal contact section min

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-229609 (JP, A) JP-A-3-68909 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 39/14 B21B 1/00-11/00

Claims (1)

(57) [Claims 1] In a four-roll rolling mill for bar and wire rod rolling, the rolled material contact portion of the guide roller between stands is set to the caliber center point of each rolling roll in the first pass of the passing material .
The Rukoto contacting the four points corresponding to the first pass roll caliber 4 rolling mill stands between the guide rollers of which were characterized by not impair the torsion binding against change of the rolled material shape due to wear of.