JPS59215233A - Production of pc steel or steel stranded wire - Google Patents

Abstract

PURPOSE:To perform strain tempering at a low cost with a small sized installation by connecting two pairs of capstans having different diameters via hydraulic disc brakes to apply tensile strain on the wire and controlling tension and temp. between a weld zone and a non-weld zone. CONSTITUTION:A PC steel wire or steel stranded wire 1 to be treated is wound around capstans 2-1a, 2-1b from an arrow direction and is then passed through a heating coil 8 and a water cooling nozzle 9 until the wire is wound half around a turn roller 3. The wire is then wound around capstans 2-2a, 2-2b having a larger outside diameter and is coiled on a coiler. A disc brake 14 is actuated to grip disc 13 and to connect the capstans 2-1a, and 2-2a, 2-1b and 2- 2b in the stage of applying tension on the wire 1. Tensile strain (or tension) is generated continuously on the wire 1 between the capstans having different circumferential speeds. The wire is heated by the coil 8 and is cooled by the nozzle 9 under such strain, by which the wire 1 having a low relaxation characteristic is produced.

Description

Detailed Description of the Invention (a) Technical field The present invention relates to a manufacturing method for improving the laxation properties of PC (press rest concrete) steel wires and steel stranded wires (7) used for concrete reinforcement, etc. .

←）Background technology Conventionally, in order to impart low luxation properties to PC steel wires and steel stranded wires, strain-removal methods have been used to remove strain under tension.
Tempering process is being performed. There are three methods for applying tension in this process:

(1) Method of applying tension with two caterpillar capstans with different speeds (1) Method of applying tension by winding around two double capstans with different diameters (1) Utilizing the special skill of dies Among these methods, method (1) is limited to the case of steel wire, and in many cases (method 0) is used. However, in any of these methods, the tension is the breaking load of 3
Since the heating temperature is as high as 0 to 50% and the heating temperature is approximately 650°C, there is a problem that the connection portion of the PC steel wire or steel stranded wire is likely to break. To solve this problem, the PC
Usually, steel wires and steel stranded wires are connected using grip couplers for continuous processing. However, in the conventional method, the grip coupler is a consumable item and costs high, and since the outer diameter of the coupler is large, it is not possible to apply tension with a caterpillar capstan, and with a double capstan, the groove width needs to be widened, which requires equipment. It becomes large. Furthermore, when high-frequency heating is used, the inner diameter of the heating coil increases, resulting in a significant drop in heating efficiency. Therefore, there were many problems in terms of productivity, equipment cost, and energy saving.

(C) Disclosure of the Invention The present invention solves the above-mentioned problems and provides a strain tempering method that uses relatively small equipment and has low production costs. The content of the present invention will be explained with reference to FIG. Figure 1 shows the same outer diameters of the invention, 2-2a and 2-2b.
The outer diameter is about 1.0% to 1.5% larger than the former with the same outer diameter. Further, capstans 2-1a and 2-1b are fixed to the shaft 7, but capstans 2-2a and 2-2b are not fixed to the shaft. The number of grooves for winding the cap stan is preferably 5 to 8. Insert the PC steel strand 1 to be processed into the capstan 2-1 from the direction of the arrow.
After winding 6 turns around a and 2-1b, the heating coil 8.
Pass it through the water-cooled nozzle 2 and wind it around the turn roller 6 for half a turn.
Next, a double capstan 2-2a having an outer diameter larger by, for example, 1.5% than the capstan.

2-2b for 5.5 turns and led to a winder (not shown). When applying tension, use disc brake 1.
4 grips the disk 13, the capstans 2-1a, 2-2a, 2-1t) and 2-2b are connected, and tensile strain ( or tension) is generated continuously. By heating with a high frequency heating coil 8 and cooling with a water cooling nozzle 9 under this tensile strain, a PC steel stranded wire with low luxation properties is obtained. The heating temperature in this case is 6
00 to 400°C, but if the temperature is low, the breaking load will be high and the relaxation value will be low, but the elongation will be poor.On the other hand, if the temperature is too high, the elongation will be good but the breaking load will be low and the relaxation value will be large. Therefore, it is preferable to select the temperature between 600 and 400°C. The tensile strain varies depending on the diameter difference of the double capstan, but if the diameter difference is 1.0 to 1.
If it is within the range of 5%, a wire stranded with PC steel with a small relaxation value can be obtained.

A diameter difference of 1.5% or more has little effect on the relaxation value, and on the contrary, wire breakage increases more than with PC steel.

In this case, the method of connecting the PC steel strands is by heat pressure welding and then left to cool. The strength of this weld is approximately 90 ki'/,
Furthermore, this welded part has a strength of 90 when heated to 650℃.
It is halved from kg/l. On the other hand, the strength of PC steel strands is approximately 200"/d, and the tension due to the double capstan is 60-50% of that, so the tensile stress is 80-1
00'/. Therefore, if left as is, it will break at the weld. Another feature of the method of the invention is to control the tension in this weld. During continuous operation, the disc brake 14 operates at a high pressure setting value of, for example, 100 kg/d, grips the disc 16 with high pressure to prevent it from slipping, and the capstans 2-1a and 2-2
a, 2-1b and 2-2b rotate at the same angular velocity.

In other words, the wire is pulled from the PC steel by a speed difference of 1.5%,
It is heated to about 350'C at the heating coil 8 and a permanent elongation of about 0.8% occurs. From the moment the welded part enters the capstan '2-1a, during the 4 turns of winding,
The hydraulic pressure is set to low pressure by the hydraulic control device 17 7,
Cap stands 2-1a and 2-2a and 2-1b and 2-
The speed difference between 2b is less than 1.5% (0,5%
(preferably), as a result, the tension of the wire is also lower than that of PC steel. The tension at this time is preferably 60 to 35% of the breaking load of the PC steel wire in order to ensure low lactation performance. Furthermore, before and after the welding part enters the heating coil 8, the heating source is turned off or the heating output is lowered so that the temperature of the welding part does not rise above 200°C. The heating is returned to normal temperature before and after the weld exits the 10-thermal coil. Further, after the welded portion wraps around the capstans 2-2a and 2-2b and leaves the capstan, the oil pressure is returned to the original high pressure setting value. The low pressure setting value of the hydraulic pressure is determined while checking the value of the load cell 11 so that two or more tensions to be processed are applied. Next, an example will be explained.

Example: PC steel stranded wire of grade 270 (12,7'7111
was subjected to srain tempering treatment according to the method of the present invention under the conditions shown in Table 1, and the results shown in Table 2 were obtained.

The breaking load of the normal part of the sample material is 19.500 kq, the breaking load of the welded part is 9.000 kg, and the relaxation test conditions in Table 2 are as follows: The initial load is 70% of the standard breaking load and 1000 kq. It is shown as the load reduction rate after time. As shown in the table, sufficiently low luxation values were exhibited in the normal area and the welded area (low-pressure treated area), and stable processing was achieved without any breakage of the welded area during processing.

Table 1 Processing conditions Table 2 Relaxation ml Figure 2 shows the changes in tension applied to the PC steel wire in this example, detected and recorded by a load cell as it passes through the welded area, and 25 indicates low pressure treatment. , 22.27 is a high pressure processing section.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the equipment used in the manufacturing method of the present invention, Figure 2
The figure is a diagram showing changes in tension for explaining the present invention. 1: PC steel wire, PC steel stranded wire, 2-1a, 2-1b
. 2-2a, 2-2b2: Capsun, 6: Turn roller, 4: Drive shaft, 5: Transmission gear, 6: Bearing. 7: shaft, 8: heating coil, 9: water cooling nozzle, 10: hydraulic rotary joint, 11: load cell. 12: Thermometer, 16: Disc, 14: Disc brake, 15: Hydraulic pump, 16: Solenoid valve. 17: Hydraulic control device, 18: High pressure setting switch. 19: Low pressure setting switch, 20: Hydraulic hose, 21: Oil tank, 22, 23: High pressure treatment, 26: High pressure-low pressure switching, 24: Heating stop, 25: Low pressure treatment. Procedural amendment Showa f? Kazuo Wakasugi, Commissioner of the Japan Patent Office, July 7, 2017, 1, Incident Display BI! 2005 Patent Application No. 88486 2, Name of the invention: PC steel wire, manufacturing method of steel stranded wire 3, Relationship with the case of the person making the amendment Patent application Person: Address: 5-15 Kitahama, Higashi-ku, Osaka City
Name (213) President of Sumitomo Electric Industries, Ltd. Tetsube 4, Agent Address: 6, Sumitomo Electric Industries, Ltd., 1-1-3 Shimaya, Konohana-ku, Osaka, Japan. Explanation column 7. Contents of amendment (1) Specification, page 5, line 17, "80-100" is corrected to "60-100". (2) On the 18th line of the same page in the same book, ``broken at'' is corrected to ``mostly broken at.''・(3
) On page 6, lines 1 and 10 of the same book, rkg/mJJ is corrected to rkg/Kuchichi. (4) On the 20th line of the same page in the same book, "10 fever" is corrected to "heating." (5) On page 7, line 1 of the same book, "Return heating to normal temperature." is corrected to "Return heating output to normal." (6) On the second hit of the same page in the same book, "turn" is corrected to "2 turns." (7) Ministry of the same page, line 14, r19.500kg, J to r19.500kg, J
Correct to. (8) On the 15th line of the same page in the same book, r9.0OOJ is corrected to r9.0OOJ. (9) Table 1 on page 8 of the same book is corrected as follows.

Claims (2)

[Claims] (1) In the strain tempering process that imparts low laxation performance to PC steel wire and stranded steel wire, two pairs of capstans with different diameters are connected via a hydraulic disc brake to adjust and impart tensile strain. A method for manufacturing PC steel wire and stranded steel wire, which is characterized by controlling tension and temperature in welded and non-welded parts. (2) The PC steel wire according to claim (1), characterized in that the tempering temperature is adjusted to 600 to 400°C in the non-welded part and 200°C or less in the welded part,
Method of manufacturing steel strands.