JP3386389B2 - Manufacturing method for deformed wires and steel bars - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention
To obtain deformed wire rods and steel bars used for steel bars to be embedded
In particular, it shows excellent bending workability.
Rolling method that can improve dimensional accuracy of striped ribs and bars
About the law. [0002] 2. Description of the Related Art A general deformed steel bar is shown in FIG.
A predetermined joint 2 and two vertical ribs 3 are provided on the circumferential surface of the sea urchin bar.
Are formed. Part excluding knot 2 and rib 3
Minute (free surface) 5 diameter D, node 2 height t, adjacent in the axial direction
The distance L between the nodes 2 and the width d of the rib 3 are determined according to JIS standards.
In particular, for the height t of Section 2,
The range is strictly set. In contrast, FIG.
(B) A four-ribbed variant having four longitudinal ribs 3 as shown in FIG.
Steel bars 1 are known. Four-section ribs are commonly used
In bending during use compared to 2-rib deformed steel bars
No kinking or bending, and excellent workability
One. [0003] The rolling method of this type of 4-rib deformed steel bar is
The present applicant has performed the final finishing rolling by using a four-roll rolling mill.
A method for performing the above-described method has been proposed (Japanese Patent Laid-Open No. 7-32330).
2). This is a pair of two rolls as shown in FIG.
R_1,R_TwoAnd R_3,R_FourAnd are arranged in an orthogonal cross shape.
Each finishing roll R forming the final finishing pass₁~ R_FourIn
In the circumferential groove 6 having an arc-shaped cross section, along the circumferential direction as shown in FIG.
The node grooves 7 are formed at predetermined intervals. Four of these
Finishing roll R₁~ R_FourFormed by the roll gap
A round cross-section is formed on the round hole die 8 by the rolling mill row on the upstream side.
Rolled down through the rolled material to be rolled,
To form At the same time, bites into the gap between adjacent rolls
Thus, four vertical ribs 3 are formed. [0004] However, this is not the case.
Una 4 finishing rolls R₁~ R_FourStraight material with circular cross section
For producing deformed wire rods and deformed steel bars by rolling down from the cross direction
If the product dimensions vary greatly for the following reasons,
In particular, there is a problem that it is difficult to obtain dimensional accuracy of the outer shape. [0005] That is, the free surface 5 without the node 2 is naturally pressed down.
The material is stretched in the longitudinal direction in proportion to the area reduction.
I will try. Therefore, it is normally supplied to the roll joint groove 7
The meat of the material that should be
It becomes meat closing (pull-down), and the node height t
Tend to be smaller. This pull-down phenomenon is 4
The material to be rolled is supplied by adjusting the tension on the entry side to the roll mill.
Increase the diameter of S to make the roll nodal groove 7 full of material.
It can be prevented by taking minutes. But in that case,
In addition, biting into the gap between adjacent four rolls
Since the amount increases, the outer diameter of the vertical rib 3
There is a tendency to be larger than the outer diameter. The present invention solves such problems of the prior art.
To fill the roll groove
At the same time as satisfying the degree, excessive biting of the vertical rib outer diameter
Dimension accuracy is extremely high by preventing
To provide a method for producing deformed wires and steel bars with good
Aim. [0007] Means for Solving the Problems To achieve the above object,
For the purpose of the present invention, the method for producing a deformed wire rod or steel bar
・ 4 in the last two passes in the continuous finishing and rolling line for steel bars
A rolling mill is installed, and the upstream four-roll rolling mill and its
The tension between the stand and the pre-rolling mill is 0.2 to 1.2 kgf /
mm^TwoAs a bite on the surface of the material to be rolled at the knots and four places around the circumference
To form a vertical rib, and further, the
The vertical ribs are shaped by pressing down. [0008] Embodiments of the present invention will be described below with reference to the drawings.
This will be described with reference to FIG. FIG. 4 shows the deformed wire rod and steel bar of the present invention.
The main part of the continuous finish rolling line of No. is shown. This is illustrated
Base material S passed through the rough rolling mill group and intermediate rolling mill group
After finishing rolling mill group L to be processed into
The two 4-roll rolling mills P1 and P2
They are arranged in series shifted by 45 °. in this case,
The configuration of the finishing mill group L is not particularly limited. Illustrated
Is n stands Ls₁~ Ls_nFinish consisting of
The rolling direction of the rolling mill is alternately changed horizontally and vertically.
HV alternately arranged, but any other good
No. [0009] First, a base material S having a square cross section is placed in a rough rolling mill.
Vertical rolling and horizontal rolling by flat roll of group
By caliber-less rolling while alternately changing
And gradually reduce the base material cross-sectional area. Then, in the middle
After passing through the rolling mill group, the oval hole type and
Lowering from vertical direction and horizontal direction alternately with window hole type
And a circular cross section. Finally, the rolling direction is changed to 45
Round of two 4-roll mills P1 and P2 shifted by °
Two-to-four rolls, each of which has a groove,
Rolled from two directions perpendicular to each other, as shown in FIG.
On the circumferential surface of the knuckle, there are two vertical ribs of section 2 and 4
C) A deformed steel bar 1 having 3 is manufactured. [0010] At this time, 4
Upstream rolling mill of roll rolling mill (round hole type)
P1 and the pre-rolling mill (round hole type) Ls immediately before P1_nWith
A tension is applied to the material to be rolled in between. The tension is applied at each pressure.
A single drive system that drives the mill with a dedicated motor
Even if the rolling speed of the rolling mill is adjusted,
Roll gap adjustment with common drive system where drive shares drive motor
May be performed only with adjustment, but more precise dimensional accuracy guarantee and
From this point of view, the single drive system is preferable. For example, Lord
The motor rotation speed depends on the motor load current value during
By adjusting the rolling, the upstream four-roll mill P1
And the rolling mill Ls immediately before_nTo be given to the material to be rolled between
It is possible to roll while controlling tension quickly and finely.
is there. [0011] The pressure of the four-roll rolling mills P1 and P2 in the final pass
Roll roll R₁~ R_FourHas a roll R shown in FIG.₁, R_Two
Similarly, a circumferential groove 6 having an arc-shaped cross section is formed on the peripheral surface of the roll.
And a nodal groove with a predetermined width perpendicular to the circumferential direction on the groove surface of the circumferential groove 6.
7 are engraved at predetermined intervals. A four-roll rolling mill P having such a groove shape
2 to 4 rolling rolls R of 1₁~ R _FourThe row formed by
Rolled material on the entry side of the gap 8 (that is, round hole type)
Rolling roll R while applying tension to S₁~ R_FourDepress with
You. In this case, the immediately preceding rolling mill Ls_nSupplied from round hole type
The material S to be rolled has a substantially round cross section as shown in FIG.
is there. The outer diameter H of the material to be rolled is the pressure of the four-roll rolling mill P1.
Roll roll R₁~ R_FourCircle formed by the groove bottom 7a of the joint groove 7
The diameter of the cross section (hereinafter referred to as “knot head diameter”) L_7aAbove
You. The material S to be rolled through the round hole die as described above
Diameter H of the roll hole type_7aIf greater than,
In the state where tension is applied to the material S to be rolled, the rolling roll R₁
~ R _FourWhen rolling down, the material to be rolled S is in the longitudinal direction
Elongation due to tensile stress in addition to the elongation to the outside diameter H
Is rolled while reducing the diameter more than without tension.
You. However, as the outer diameter is large, extra material rolls
Since it is supplied into the grooved groove 7, the round grooved groove is provided.
7 is good, no large pull-down
No. Therefore, the knot height t of the product deformed bar 1 is reduced.
No roundness is good. At this time, each adjacent rolling which is a non-rolled portion
Roll R₁~ R_FourThe material S to be rolled is
The ribs 3 of the deformed bar are formed (FIG. 5).
The bite 10 is a rib outer diameter L of a deformed steel bar._ThreeThe regulations
Because no rolling force is applied, tension is applied.
When rolling is carried out as it is, the deformed steel bar of the product is shown in Fig. 6.
So that the rib outer diameter L_ThreeIs the joint outer diameter L_TwoMuch larger than
You. However, by rolling while applying tension,
Reduction of outer diameter H of entry side rolled material S supplied to round hole mold
Larger ratio (ratio of reduced diameter to original outer diameter H)
As a result, the biting of the rib 3 is also reduced. FIG. 7 shows the immediately preceding rolling mill Ls_nAnd 4 rows upstream
Of the tension between stands between the rolling mills P1 and the rib outer diameter L
_Three6 is a graph showing a relationship with the graph. As shown in the figure,
The magnitude of the tension between the stands is from 0 to 0.2, 0.5, 1..
2kgf / mm^Two4 rolls on the upstream side
The start of the rib 3 formed by the rolling mill P1 is reduced.
And rib outer diameter L_ThreeGradually becomes the target size
Nodal diameter L_TwoIt can be seen that it approaches. In the present invention, the upstream four-roll rolling mill
With the start of the P1 pass, the node outer diameter L_TwoGreater than
Outer diameter L_ThreeThe protrusion of the rib 3 formed with
And press down and shape in the pass of the 4-roll rolling mill P2 on the downstream side
You. In the upstream four-roll rolling mill P1, for example, two pairs of
Roll R₁, R_ThreeAnd the roll R
_Two, R_FourAre horizontally opposed to each other, the rib 3 is inclined 45 °
It is formed by biting in the direction. 4-roll mill on the downstream side
At P2, each roll is rolled so that the rib 3 is shaped and pressed down.
Vs. R₁, R_ThreeAnd R_Two, R_FourOblique direction from cross
For 45 degrees. FIG. 8 shows the four rolls on the upstream side.
Rib 3 formed by biting in the pass of rolling mill P1
Is reduced by a 4-roll mill P2 on the downstream side and shaped.
FIG. At this time,
From the section 2 of the rib 3 in the four-roll rolling mill P1 of the stage
If the protrusion amount a is too large, the rib pressure reduction amount will be too large.
The material to be rolled rotates as indicated by the arrow symbol θ, and the portion of the rib 3 is
From position (a) to position (b), that is, the roll clearance
The rib 3 is not lowered.
It will be normal. Therefore, the upstream four-roll rolling mill P1
Immediately before that, the magnitude of the tension between stands between the rolling mills L4 is
It is necessary to control so that the protrusion amount a of the valve 3 does not become excessive.
The size is 0.2kg / mm^TwoNeed more
It is. On the other hand, the shape of wire rods and bars that can be manufactured by hot rolling
There is a limit to the accuracy of shape and dimensions, and the rolled material obtained is perfect
No point-symmetric cross section. Of such asymmetric cross section material
If excessive tension is applied during rolling, the rolling material
Rotation occurs. Therefore, the upstream 4
From the rolling mill P1 to the downstream four-roll rolling mill P2.
While entering, the position of the rib 3 is the proper position (a)
From (b) to the roll plow position,
As a result, the rib 3 remains undepressed. Like this
The limit of the tension application that causes rotation of the rolled material is 1.2 kg /
mm^TwoTurned out to be. That is, rolling of the deformed wire rod and the steel bar of the present invention.
In the method, the upstream four-roll mill P1 and the pressure immediately before it
Rolling machine Ls_nThe magnitude of the tension applied between the stands
0.2-1.2kg / mm^TwoAnd As mentioned above,
0.2kg / mm^TwoIf the tension is less than
Is excessive and the rib 3 starts to bite excessively,
No pressure is applied when the ribs 3 are pressed down by the side 4 roll rolling mill P2.
The rolled material does not rotate at the proper position and the product is not
The outer diameter of the bush becomes defective. On the other hand, the upper limit is 1.2 kg / mm
^TwoWith a tension exceeding, the rolled material itself with an asymmetric cross section
Is rotated, and as a result, as described above,
Rolling mill P2 does not achieve proper reduction, and the product
Dimensional defects occur. [Embodiment] The material S to be rolled to the upstream four-roll rolling mill P1 was
The upstream side 4 b so that the entry side dimension is 10.5 mm in diameter
Rolling mill P1 and the immediately preceding rolling mill Ls_nAnd between stands
The magnitude of the tension is approximately 0.4 to 0.7 kg / mm^TwoAdjust to
did. Roll hole die 8 of upstream four-roll mill P1
The dimensions of are shown in FIG. Roll hole diameter 9.0mm, groove of nodal groove
The diameter between the bottoms 7a was 10.0 mm. In addition, 4 b downstream
FIG. 10 shows the dimensions of the roll die of the roll mill P2. each
Roll R₁~ R_FourRadius of curvature R of the surface pressing rib 3
5.2 mm, and the opposing interval was 9.9 mm. to this
Can produce deformed bar products that pass JIS standards
Was. [0021] As described above, the variant according to the present invention
According to the method of rolling wire rods and bars, four rows are required for the last two passes.
Pre-roll tension at the upstream roll mill
Control to the range, and the rib portion on the downstream roll mill.
The ribs are shaped by pressing down the ribs.
The rotation of the material can be prevented, and as a result, the product
This has the effect of improving the dimensional accuracy of shaped wires and steel bars.
You.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an example of a deformed steel bar, in which (a) is a two-rib deformed steel bar and (b) is a four-rib deformed steel bar. FIG. 2 is a front view illustrating a roll arrangement of a four-roll rolling mill. FIG. 3 is a schematic diagram showing an example of a groove shape of a roll of a final finishing mill in deformed bar rolling. FIG. 4 is a schematic diagram illustrating an example of a path schedule according to the present invention. FIG. 5 is a sectional view showing a dimensional relationship between a roll hole die and a material to be rolled in a four-roll finishing mill of the present invention. FIG. 6 is a view showing an example of a cross-sectional shape of a deformed steel bar when rolled by an upstream roll mill without applying tension. FIG. 7 is a graph showing the relationship between the stand-to-stand tension between the upstream four-roll rolling mill and the immediately preceding rolling mill and the protrusion size of the rib. FIG. 8 is a diagram illustrating the effect of the inter-stand tension on a downstream four-roll rolling mill. FIG. 9 is an explanatory view of a groove of an upstream four-roll rolling mill in an embodiment. FIG. 10 is an explanatory diagram of a groove shape of a downstream four-roll rolling mill in an embodiment. [EXPLANATION OF SYMBOLS] 2 Section 3 ribs 7 Fushimizo R ₁ roll R ₂ roll R ₃ roll R ₄ roll S material being rolled P1 upstream 4 rolling mill P2 downstream four-roll rolling mill Ls _n upstream four-roll rolling mill Rolling mill just before

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-323302 (JP, A) JP-A-11-47804 (JP, A) JP-A-11-90505 (JP, A) 94602 (JP, A) JP-A-54-124861 (JP, A) JP-A-8-33901 (JP, A) JP-A-56-6701 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) B21B 1/16-1/18 B21B 13/12 B21H 8/00 E04C 5/03

Claims (1)

(57) [Claims 1] A four-roll rolling mill is disposed in the last two passes in a continuous finishing rolling line for wire rods and steel bars, and a four-roll rolling mill on the upstream side and a rolling mill immediately before the four-roll rolling mill are arranged. Set the tension between stands to 0.
A node and four circumferential ribs are formed on the surface of the material to be rolled at a pressure of ^{2 to} 1.2 kgf / mm ² , and the downstream rib 4 is formed.
A method for producing a deformed wire rod or a steel bar, wherein the vertical ribs are pressed down and shaped by a roll rolling mill.