JPS622883B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing round steel bars and deformed steel bars (hereinafter referred to as steel bars) by hot multi-strip rolling of steel bars.

In recent years, in order to improve productivity and quality in rolling steel bars, non-twist rolling with a wide range of rolling speeds and vertical rolls has become popular. Particularly for fine size products (10 to 16 mm), a method called slit rolling is also adopted in which a rotating knife blade installed in a guiding device is used to split the product into two parts at the point where it leaves the oval roll near the finishing roll. .

For example, JP-A-51-119583 or JP-A-52-
In the publication No. 116762, a so-called slit rolling method is proposed.

The present inventor analyzed and studied the conventional slit rolling method, and based on Japanese Patent Application No. 57-109893, the oval hole shape surrounded by the upper and lower slit rolls was
We proposed a multi-strip rolling method for steel bars in which oval inclination angles β are arranged symmetrically.

The present invention preferably regulates the inclination angle β of a plurality of ovals surrounded by the upper and lower slit rolls to 20° each, and uses slit rolls arranged with the inclination angles inclined in the same direction,
This paper proposes a multi-strip rolling method for steel bars that involves slitting.

The present invention will be explained in detail below with reference to the drawings.

Figure 1 shows an example of three-slit rolling. The part manufacturing method of the present invention involves passing a billet having the cross section shown in FIG. 1A through rough and intermediate rolling mills multiple times.
Create a flat cross section B with a thickness of H ₁ and a width of W ₁ as shown in Figure 1 No. 1.

Next, use No. 2 to roll down section B to a thickness of H ₂ and make two cuts to create starting section C divided into three sections. Width of C ₁ = width of C ₃ , C ₁・C ₃
Width > C ₂ width.

Next, turn the C section 90 degrees and attach it to No. 3. C
The width W ₂ of is compressed to W ₃ , but as a result, the thickness H ₃ of the D section becomes slightly larger, and the section of the three rounded sections d ₁ , d ₂ , and d ₃ becomes almost It becomes equal. No. 4 roll has flanges P ₁ and P ₂
It is a blind hole type with . The inclination angle of the two cuts is θ=95°, and they are separated from the center at θ ₁ =θ ₂ =47°50′. Reduce the thickness to H ₄ and make deeper cuts. The thickness of the joint part shall be 4 mm.

No. 5 F is the preparation cross section for slitting with No. 6 roll. The widths of W ₅ and W ₄ are almost equal. The cutting angle δ is 90°. δ ₁ of cut = 40°・
Distribute to δ ₂ = 50°. The thickness of the joint part is 2mm
shall be. The ovals f ₁ , f ₂ , f ₃ forming F are blind hole types with equal areas and have flanges P ₁ and P ₂ .

That is, according to the present invention, incisions are made from four holes before the slit roll, the cross-sectional dimensions of the holes to be divided are made approximately equal to each other, and the thickness of the connecting portion of the cuts is 2 mm. .

No. 6 is a roll for slitting. FIG. 1 shows three divisions. Each oval has a blind hole shape. Ovals g ₁ , g ₂ , and g ₃ with an inclination of 20° to the center line are arranged as shown in the drawing.

That is, the oval hole shapes g ₁ , g ₂ and g ₃ surrounded by the upper and lower slit rolls are each given an inclination angle β, but the inclination angles β are inclined in the same direction.
Therefore, the engagement angle α of the blades is also inclined in the same direction.

The engagement depth S of the blades of the upper and lower rolls is 3 mm. The engagement angle α of the blades shall be 10°, and the clearance of the blades in the S portion shall be 0.3 to 0.5 mm. Also, the slopes m and n of the flanges on both sides of the hole mold are set to about 8 to 10%. This is made smaller than the slope of α of the meshing blades. That is, the purpose is to protect the blades by not applying the thrust directly to the engaging blades, but to applying the thrust to the flanges P ₁ and P ₂ first.

According to the inventor's experiments, the oval hole type array surrounded by the upper and lower slit rolls is arranged at the same slope for both odd and even number divisions. Figure 1
The arrangement shown in No. 6 has three slits, FIG. 2 shows the arrangement with two slits, and FIG. 3 shows the arrangement with four slits. In either case, the appropriate inclination angle β of the oval with respect to the center line is about 20°. Also, the meshing angle α of the blades of the upper and lower rolls is 10°, and the meshing depth S
It is desirable that the blade clearance be 3 mm and the blade clearance be 0.3 to 0.5 mm.

In order to perform the above-mentioned slitting process smoothly, the inclination angle θ of the valley of the slit portion of the hole mold two before the slitting roll is set to 95°, and the slope angle θ of the valley of the slit portion of the hole mold immediately before the roll is set to 95°. is 90°, but there is no particular limitation. In addition, by arranging each oval in the No. 6 slit at an angle of 20 degrees to the center line, the roll hole shape causes the divided material to leave the roll through the fund at an angle of 90 degrees to the roll axis. The twist of the material itself helps, and it also makes it easier to divide and introduce into the next hole type.

The preparation material that comes out of No. 5 is fed into No. 6 roll as it is, and is sheared and divided by the upper and lower rolls. No.6 g ₁ ~
The width of the oval g ₃ is almost the same as the width f ₁ to f ₃ of No. 5, but the thickness is H ₆ <H ₅ . No.6
At the same time, each oval cross section is slit, and at the same time the central part is strongly compressed, but the ends are made lighter.

According to experience, it is desirable to perform slitting during rolling with a reduction rate of 10 to 20%, but considering the load on the cutting edge, it is better to select a smaller reduction rate for large items and a larger reduction rate for small items. good.

That is, according to the present invention, by stretching the central portion, the thin portion is pulled, thereby reducing the load on the blade portion. This protects the blade, cleans the cut end, and prevents large burrs from forming at the cut end.

As described above, in the present invention, the hole shapes of the upper and lower slit rolls are out of phase with each other, and a state in which the material is squeezed diagonally is formed, and an interlocking blade is formed by the upper and lower rolls passing each other. . Until now, the action and effect of Thriztrol had not been recognized at all.

In addition, with this slitting method, regardless of the size of the steel bar, if the diameter of the cross section of the product is 1, the inside and thickness of the oval of the slitting roll is 2.15 x 0.76 x 0.785.
Since the multiplier and the ratio are kept constant, the load on the cutting edge of the roll during slitting hardly changes regardless of the size of the product.

Furthermore, as mentioned above, the inclination angles β of the oval hole types g ₁ , g ₂ , and g ₃ are inclined in the same direction, so the material prepared in No. 5 requires the use of a specially prepared guiding mechanism. It is suitable for simplifying equipment because it can be fed to a No. 6 slit roll for slitting.

Next, the three oval pieces of g ₁ to _{g 3} slit by No. 6 are each slit at an angle of 70 degrees with a fund, so that they are oriented at 90 degrees with respect to the roll axis, but at the same time the distance between them is widened. No.7 roll h ₁ ~ _{h 3}
It is guided by the hole pattern and the oval shape is adjusted.

The divided materials h ₁ to _{h 3} that have passed No. 7 enter the No. 8 roll without twisting, are transformed into i ₁ to i ₃ , and then enter the No. 9 roll without twisting, j ₁ It is transformed as ~j ₃ .

The oval material coming out of the No. 9 roll is twisted at 90 degrees here, and the final roll of No. 10 yields three products k ₁ , k ₂ , and k ₃ at the same time. Although the figure shows a deformed steel bar, the same applies to round steel.

As described in detail above, according to the present invention, it is possible to select an appropriate number of slits based on the product size and roll a steel bar in multiple strips at the existing roll speed, which has great industrial effects.

[Brief explanation of the drawing]

Fig. 1 is a process explanatory drawing showing the slot series of the present invention using a three-slit example, Fig. 2 is a two-slit slot layout diagram, and Figure 3 is an explanation of a four-slit slot arrangement. It is a diagram. S...depth of engagement, m...flange slope, n...
Flange slope.

Claims (1)

[Scope of Claims] 1. A rolled rough material having a preformed cross-section so that the cross-sectional area of each bar after division is equal, corresponding to the number of steel bars required to obtain multiple steel bars at the same time through hot rolling. is introduced into a slit roll, flanges forming blind hole shapes are provided at both ends of the slit roll, and a plurality of blind hole shapes surrounded by the upper and lower slit rolls have an inclination angle β, and each of the inclination angles is the same. The oval material is made into an oval material by slitting it during rolling with interlocking blades having an inclination angle α with the adjacent blind hole shape, and holding the oval material at 90° with respect to the roll axis. A method for rolling multiple strips of steel bar, characterized in that each strip is rolled using subsequent groove rolls. 2 For multiple oval blind holes, the inclination angle β is
2. The method of multi-strip rolling of a steel bar according to claim 1, wherein slitting is performed during rolling at a rolling reduction rate of at least 10%.