JPH0371202B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a blast cooling device for rolling out and conveying hot rolled wire rods into a ring shape on a roller conveyor. As shown in FIG. 1, hot rolled wire rod 3 is rolled by a rolling mill 4 and slowly cooled by a water cooling device 5.
is wound up by a winding machine 6 and spread out in an eccentric ring shape on the conveyor 1. If the conveyor type is a roller conveyor, the ring-shaped wire is cooled by blast cooling provided below the row of rollers. Cold air blows upward between the rolls from a large number of air cooling nozzles 2 arranged in the device 2' and directly hits the wire to cool it. In this case, conventionally, as shown in Figure 2 (plan view), the arcuate portions of the rings overlap at the edges in the width direction of the conveyor, and the coil density is higher than at the center, making it difficult to cool the wire material. It is the biggest cause of quality variations in properties. SUMMARY OF THE INVENTION The present invention provides an effective cooling device for a ring-shaped wire, which effectively cools the end portions to maintain a uniform cooling balance with the center portion. The present invention provides an apparatus in which a hot rolled wire rod is rolled out into a ring shape on a roller conveyor and conveyed while being blast-cooled from below the conveyor. In addition, the length of the center part of the body is 70 of the ring wire diameter.
This is a blast cooling device for conveyor conveyance of ring-shaped wire rods, characterized by a cooling rate of ~90%. The present invention will be explained in detail below with reference to the drawings. FIG. 3 is a plan view of the conveying device according to the present invention, and FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3. The conveyor roll 1 is characterized by its shape.
This is because the roll diameters of the roll a and the lengthwise ends 1b and 1b' are different. That is, 3rd to 4th
As shown in the figure, differences in roll diameter are provided by forming stepped rolls or by adding concave curves or linear inclinations, but in order to avoid duplication of explanation, detailed explanation will be given below by taking the stepped roll as an example. First, the diameter of the long body center portion 1a is the same as the diameter of a normal conveyor roll, but both ends of the body length have a smaller diameter than this long body center portion 1a, and the difference is the diameter 1b of both ends of the body length. Or 1b'/center diameter of trunk length 1a x 100
% = 20-90%. According to the inventors' experiments, the above diameter ratio is 20%.
If it is less than that, the mechanical strength of the roll shaft will be insufficient. or
If it exceeds 90%, the effects of the invention described below cannot be expected. Next, regarding the area conditions of these large-diameter portions and small-diameter portions, the trunk length l of the trunk length central portion 1a is slightly shorter than the diameter D of the ring-shaped wire 3 developed on the roll. Design it like this. In this embodiment, both end portions 3' of the eccentric ring-like high-density ring protrude outward from the central portion 1a of the body length. When incorporating this protruding part into the design, according to the experiments conducted by the present inventors, in practical terms, the central length of the trunk length l/ring-shaped wire diameter D x 100% = 70 to 9
I found out that setting it to 0% is sufficient. If it is less than 70%, troubles will occur, such as (i) the end of the ring will sag and become deformed, (b) the loading condition will become unstable, and (c) the ring end will get caught in the small diameter part during transportation. If it exceeds 90%, the air cooling effect of the dense ring-shaped overlapping portion will be weakened, and the effects described below will not be obtained. Desirably around 80% is generally effective. By providing a step in the roll diameter as described above, there is a difference in the interval between adjacent rolls, that is, the area of the refrigerant passage, and the air volume from the two groups of air cooling nozzles arranged below is increased between the central part 1a of the body length and both ends. Part 1b, 1
Due to the difference in b′, the cooling effect becomes higher in the denser part of the ring-shaped wire. In order to make this cooling effect even larger and more effective, a difference is made in the arrangement conditions of the air cooling nozzles 2 below the central part 1a of the body length and below both ends 1b, 1b' of the body length. For example, the central zone A1 in Figure 3
Consideration may be given to increasing the number of the two groups of wind cooling nozzles in both end zones A2 or increasing the air volume or speed of the two groups of air cooling nozzles in the two end zones A2. In addition, it is better to complete the cooling in a short time, and uniform cooling is required in accordance with the density pattern of the ring-shaped wire, so if the balance between the cooling effects of A1 and A2 can be adjusted, it will be easier in the implementation process. Furthermore, it is possible to make fine balance adjustments in the width direction, making it possible to achieve uniform quality. Further, the roller arrangement can of course be combined with conventional stepless rollers. Next, examples according to the present invention will be shown. The type is based on the illustrated examples in Figures 3 and 4, and the diameter of the roll is 100 mmφ at the center part 1a.
Both ends 1b and 1b' are 45mmφ, and the corner radius of the step is 20mm.
mmR, the length l of the center of the roll is 840mm, the pitch between the rolls is 200mm, the diameter D of the ring-shaped wire is 1070mm
mmφ (conveyance pitch 40 mm). Also air cooling nozzle 2
As shown in Figure 3, the arrangement of the ring-shaped wire rods is adjusted to the density of the ring-shaped wire rods, with one piece per 1 m in the conveyor conveyance direction at the center of the conveyor, and two pieces per 1 m in the conveyor direction between the rolls at both ends 1b and 1b'. Pieces x 5 = 10 pieces. However, fine cooling balance adjustment according to the ring density is performed with reference to the theoretical coil density distribution shown in Figure 5 (in Figure 5, x indicates the conveyor width direction and y indicates the conveyor conveyance direction). or,
The air volume per nozzle was the same for each nozzle. In Figure 5, the coil overlap density sx/so is It is expressed as FIG. 6 shows the wind-cooled nozzle distribution of the conventional method [FIG. 6a] and the wind-cooled nozzle distribution of the present invention [FIG. 6b]. The sample material has a diameter of 5.5φ and a composition of C: 0.61%.
After hot rolling the wire using a hard steel wire with Si: 0.24% and Mn: 0.55%, approximately 800
During the rapid cooling to ℃ and transfer by winder to a conveyor, air was used as the cooling liquid and the cooling rate was set to 8℃/sec. Using. As a result of carrying out the test under these conditions, as shown in Table 1, the variation in the mechanical properties of the wire rod was greatly improved compared to the conventional method, as shown in Table 1.

[Table] As shown in Table 1, the mechanical strength variation σ of the conventional roller conveyor with a uniform roll diameter has an extreme difference between the center and end portions of the coil, but according to the roller conveyor of the present invention. The difference between the center and edges was significantly reduced, making uniform cooling possible.
It should be noted that substantially the same effect can be obtained not only with stepped rolls but also with rolls with a concave curve or a linearly sloped roll diameter difference. As described above, according to the present invention, by providing a difference in the diameter of the conveyor rolls and arranging the blast nozzles appropriately, the cooling effect of the ring-shaped wire can be made uniform and the quality can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a general example of a wire rod rolling cooling conveyance facility, FIG. 2 is a plan view of a conventional conveyance facility, FIG. 3 is a plan view of a conveyance facility of the present invention, and FIG. 4 is an A of FIG.
-A arrow view, FIG. 5 is a diagram showing the density distribution of the ring-shaped wire rod, FIG. 6 a is a distribution diagram of air-cooled nozzles by a conventional roller conveyor with a uniform roll diameter, and FIG. 6 b is a diagram of the roller conveyor of the present invention. It is a wind cooling nozzle distribution map according to. DESCRIPTION OF SYMBOLS 1... Conveyor roll, 2... Air cooling nozzle, 3... Ring-shaped wire, 4... Rolling machine, 5... Water cooling device, 6... Winding machine.

Claims (1)

[Claims] 1. In a device that rolls out a hot rolled wire rod into a ring shape on a roller conveyor and transports it while being blast-cooled from below the conveyor, the diameter of the rollers at both ends of the roller conveyor is 20 to 90% of the diameter at the center. The center length of the trunk length is 70 to 90% of the ring wire diameter.
A blast cooling device for conveyor conveyance of ring-shaped wire rods.