MAGNETIC WIRE HEAT TREATMENT APPARATUS AND MAGNETIC WIRE HEAT TREATMENT METHOD

Abstract

A tension annealing treatment consisting of a furnace and the operation method can improve magnetic properties of magnetic wire with a diameter of under 20 m and achieve continuous operation without wire breakage by controlling the temperature and tensile stress in the furnace with designated values accurately by means of a wire diameter measuring device, tension measuring device, plural capstans and tension rollers between plural capstans installed in the furnace. The interval between a wire supply bobbin and a wire winding up bobbin is divided into serval parts which are controlled to have same conveyance speed and tensile stress to dissolve the deference of each other by controlling the rotary speed of capstans and the tension loaded by tension rollers.

Claims

1. A heat treatment apparatus to apply tension annealing to magnetic wire comprising: a wire supply part comprising a supply bobbin on which magnetic wire is wound, wire reels, a capstan for supply, and a tension roller, a wire diameter and wire tension measurement part comprising a wire diameter measuring device, a tension measuring device, a post measurement capstan, a tension roller and wire reels, a tension annealing furnace comprising a furnace for heat treatment, a temperature measuring device, a post heat treatment capstan, a tension roller and wire reels, a wire winding up part comprising a wind-up bobbin, a rolling up capstan, and wire reels, a control unit comprising an input unit to receive signals given by the wire diameter measuring device, the tension measuring device, the temperature measuring device, and the plurality of capstans and tension rollers and control instructions controlling the temperature, the tensile stress of the wire and the conveyance speed in the furnace to designated values by adjusting said rotary speed of the capstans and the tensile tension of the tension roller placed between said supply bobbin and a said wind-up bobbin, to make measured values of the temperature, the tensile stress and the conveyance speed equal to the designated values respectively.

2. A heat treatment apparatus of claim 1 applied to an amorphous wire coated with an insulation material further comprising a wire diameter measuring devices to measure two diameters including an inner diameter of wire metal and an outer diameter of the magnetic wire including the insulation material on its surface.

3. A heat treatment method using the heat treatment apparatus of claim 1 to apply a tension annealing to magnetic wire within a temperature range of from 450 C. to 550 C., a tensile stress of from 50 MPa to 250 MPa and a conveyance speed of from 1 m to 10 m per minute in the furnace controlled by the measured values of diameter, tensile stress, temperature, and conveyance speed with arranged measuring instruments installed into a process in which the magnetic wire is supplied from the supply bobbin on which the wire is wound, then carried through the wire measurement part and the wire tension measurement part, subsequently inserted into the tension annealing furnace, and finally wound on the bobbin equipped with a capstan to control a rotary speed by using the capstans, the tension rollers and the wire reels.

4. A heat treatment method using the heat treatment apparatus of claim 2 to apply a tension annealing to magnetic wire within a temperature range of from 450 C. to 550 C., a tensile stress of from 50 MPa to 250 MPa and a conveyance speed of from 1 m to 10 m per minute in the furnace controlled by the measured values of diameter, tensile stress, temperature, and conveyance speed with arranged measuring instruments installed into a process in which the magnetic wire is supplied from the supply bobbin on which the wire is wound, then carried through the wire measurement part and the wire tension measurement part, subsequently inserted into the tension annealing furnace, and finally wound on the bobbin equipped with a capstan to control a rotary speed by using the capstans, the tension rollers and the wire reels.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0026] FIG. 1 is a schematic view of a tension annealing furnace for a magnetic wire.

[0027] FIG. 2 shows effects of tension annealing temperature on a magnetic property of magnetic wire.

DETAILED DESCRIPTION OF EMBODIMENTS

[0028] Preferred embodiments depend on objects for the work and performance requested from applications. The first embodiment of the present invention on the structure of a tension annealing furnace for a magnetic wire is explained as below using FIG. 1. The tension annealing furnace 1 for a magnetic wire consists of 6 parts of a wire supply part 10, a wire diameter measurement part 20, a wire tension measurement part 30, a tension annealing furnace 40, a wire winding up part 50, and a control unit 60. The wire supply part 10 comprises a supply bobbin 11, wire reels 12, a tension roller 13, and a supply capstan 14. The wire diameter measurement part 20 comprises a wire diameter measuring device 21, a post diameter measurement capstan 22, and wire reel 12. The wire tension measurement part 30 comprises a tension measuring device 31, wire reels 12, and a tension roller 13. The tension annealing furnace 40 comprises a tension annealing furnace 41, a temperature measuring device 42, a post heat treatment capstan 43, and wire reels 12. The wire winding up part 50 comprises a wind-up bobbin 51, a winding up capstan 52, wire reels 12, and a tension roller 13. The control unit 60 is equipped with a receiver 61 for sensor signals indicating such values as diameter, tension, temperature, and rolling speed and control instructions 62 for the capstans, tension rollers, the heater of the furnace to control the designated temperature and tensile stress of the wire.

[0029] The control unit 60 has an input unit 61 to receive related sensor signals as the wire dimeter, wire tension, furnace temperature, wire conveyance speed of each capstan 14, 22, 43, and 52, and the tension value of each tension roller 13 and also has control instructions 62 to keep the temperature and the tensile stress at the designated values by controlling the wire conveyance speed given by each capstan 14, 22, 43, and 52 and the tension adjusted by each tension roller 13 operated based on the value calculated from the related sensor signals.

[0030] The first embodiment is operated in series of procedures as bellow. The magnetic wire 2 wound on a supply bobbin 11 is drawn from the wire supply part 10 to the wire diameter measurement part 20 where the wire diameter is measured by the wire diameter measuring device 21. Subsequently it is carried to the wire tension measurement part 30, where the tension is measured precisely by the tension measuring device 31 and the conveyance speed and tensile stress are adjusted to the designated values respectively with tension roller 13 and the post diameter measurement capstan 22. The wire is tension annealed in the tension annealing furnace 40 at the designated values of temperature and tensile stress respectively and is carried out to the wire winding up part 50 where it is wound on a wind-up bobbin through adjusting the wire conveyance speed to the designated value by using the post heat treatment capstan 43, winding up capstan 52 and a tension roller 13.

[0031] As for the magnetic wire 2, a glass coated amorphous wire with a diameter from 10 m to 30 m is used. The wire of 1 km to 5 km is wound on the supply bobbin 11 with an inner diameter of 30 mm and with a flange. Each wire reel 12 is a V-groove roller type. Tension roller 13 can adjust the load from 1 g to 20 g with the accuracy of 0.1 g. In the case of a wire diameter of 10 m, the tension roller can control the tensile stress of from 100 MPa to 2000 MPa with accuracy of 10 MPa. Each capstan, 14, 22, 43, and 52 can control the wire conveyance speed from 1 m to 1000 m per minute by controlling the rotary speed. The tension annealing furnace is a vertical structure type free from bending stress with a furnace length of from 10 cm to 100 cm.

[0032] The temperature of the tension annealing furnace, as shown in FIG. 2, gives the most important influence on the magnetic properties and the optimal temperature range is from 450 C. to 550 C. The optimal temperature range is dependent on the alloy composition of the magnetic wire 2. In the case of amorphous alloy, the magnetic property falls extremely at the crystallization temperature around 550 C. or higher. The nearer 550 C. temperature setting of the furnace 41 is desirable to get better magnetic properties and a faster conveyance speed. But the crystallization temperature of amorphous wire 2 in the furnace varies from 550 C. to lower temperature according to the variation of the tensile stress, wire diameter, and conveyance speed. It is careful the furnace setting temperature becomes over the crystallization temperature of the amorphous alloy. Therefore, keeping tensile stress and conveyance speed controlled to designated values, the temperature is brought as close to 550 C. as possible.

[0033] The wire tensile stress is an important factor in the tension annealing method. A larger tensile stress of the magnetic wire 2 in the furnace can make more reduction in the hysteresis of the magnetic wire and more increase in the anisotropy field at temperature of near 550 C. Too big a tension load causes a strong frictional force between the rollers and the wire resulting in wire breakage. Therefore, it is very important to control the tension of the wire to a designated value. The value of the wire tension in the furnace is calculated by the tension measured by the tension measuring device 31 and the wire diameter measured by the wire diameter measuring device 21. Its value is controlled to be equal to the designated value with adjusting tension and conveyance speed using the tension roller 13 placed upstream of the furnace and the post heat treatment capstan 43.

[0034] The wire diameter measuring device 21 is produced based on some physical principles such as a laser type size measuring device, a size measuring device with magnetic impedance, and a microscope size measuring device and it can measure diameter of from 10 m to 30 m with accuracy of 0.5 m. The tension measuring device 31 is produced using a strain gage type to achieve high accuracy and it can measure a tensile stress of from 0 to 2000 MPa with accuracy of 1 MPa.

[0035] The furnace 1 has two difficult problems compared to the conventional one. The first problem is to have a longer interval between the supply bobbin 11 and the wind-up bobbin 51 than the current one because the wire diameter measuring device 21 and the tension measuring device 31 are installed. The problem is solved by dividing the long interval to four parts which are the wire supply part 10, the measuring parts 20, 30, the furnace 40 and the winding up part 50. The wire in the four parts is carried with suitable speed by each capstan placed in each part. The second problem is that the tension and speed at each part controlled by the capstan and tension roller placed are different from each other. The deference causes variation in wire conveyance speed and friction between the tension rollers and the wire to result in wire breakage. The problem is solved by the control unit which can calculate the deference of the tension and wire conveyance speed continuously and control each tension using each tension roller and each speed using each capstan at high speed of from 1 m to 10 m per minute.

[0036] The second embodiment of this invention applied to a wire covered with insulating material 2 is the first one further which is equipped with a type of a wire diameter measuring device to measure the inner diameter of the metal portion and the outer diameter of the wire covered with insulating material. The tensile stress is calculated from the net tension only loaded to the wire metal part which is divided by the metal diameter

[0037] The third embodiment is directed to a preferred method of tension annealing the magnetic wire 2 using the first embodiment or the second embodiment. This method requests to measure the diameter, the tensile stress, the temperature and the conveyance speed using the wire diameter measuring device 21, the tension measuring device 31, the temperature measuring device 42, and the capstans 14, 22, 43, 52 respectively and to perform tension annealing within the temperature of from 450 C. to 550 C., the tensile stress of from 50 MPa to 250 MPa and the conveyance speed of from 1 m to 10 m per minute in the furnace. This method is implemented as a program of the control unit 60.

EXAMPLES

[0038] The detail of the present invention is explained according to the preferred examples bellow.

Example 1

[0039] The first example is explained as below based on FIG. 1 and FIG. 2. The tension annealing furnace 1 for a magnetic wire consists of six parts of a wire supply part 10, a wire diameter measurement part 20, a wire tension measurement part 30, a tension annealing furnace 40, a wire winding up part 50, and a control unit 60. The wire supply part 10 comprises a supply bobbin 11, wire reels 12, a tension roller 13, and a supply capstan 14. The wire diameter measurement part 20 comprises a wire diameter measuring device 21, a post diameter measurement capstan 22, and wire reels 12. The wire tension measurement part 30 comprises a tension measuring device 31, wire reels 12, and a tension roller 13. The tension annealing furnace 40 comprises a tension annealing furnace 41, a temperature measuring device 42, a post heat treatment capstan 43, and wire reels 12. The wire winding up part 50 comprises a wind-up bobbin 51, a winding up capstan 52, wire reels 12, and a tension roller 13. The control unit 60 is equipped with a receiver 61 for indicating such values such as diameter, tension, temperature, and rolling speed and control instructions 62 for the capstans, tension roller, the heater of the furnace to control the designated temperature and tensile stress of the wire.

[0040] The control unit 60 has an input unit 61 to receive related sensor signals of the wire dimeter, wire tension, furnace temperature, wire conveyance speed of each capstan 14, 22, 43, and 52, and the tension value of each tension roller 13 and also has control instructions 62 to keep the temperature and the tensile stress at the designated values by controlling the wire conveyance speed given by each capstan 14, 22, 43, and 52 and the tension adjusted by each tension roller 13 operated based on the value calculated from the related sensor signals.

[0041] The first embodiment is operated in series of procedures as bellow. The magnetic wire 2 wound on a supply bobbin 11 is drawn from the wire supply part 10 to a wire diameter measurement part 20 where wire diameter is measured by the wire diameter measuring device 21. Subsequently it is carried to the wire tension measurement part 30 where the tension is measured precisely by the tension measuring device 31 and the conveyance speed and the tensile stress are adjusted to the designated values respectively with the tension roller 13 and the post diameter measurement capstan 22. The wire is tension annealed in the tension annealing furnace 40 at the designated values of temperature and tensile stress respectively and is carried to the wire winding up part 50 where it is wound on a wind-up bobbin through adjusting the wire conveyance speed to the designated value by using the post heat treatment capstan 43, winding up capstan 52 and the tension rollers 12.

[0042] As for the magnetic wire 2, a glass coated amorphous wire with a diameter of 10 m is used. The wire of 1 km is wound on the supply bobbin 11 with an inner diameter of 30 mm and with a flange. Wire reel 12 is a V-groove roller type. Tension rollers 13 load weight of 2 g (200 Mpa) with the accuracy of 0.1 g (10 Mpa) to the wire. Each capstan, 14, 22, 43, and 52 control wire conveyance speed of 1 m per minute by the rotary speed of 10 rpm with accuracy of 0.01 rpm under operation. The tension annealing furnace is a vertical structure type free from bending stress with the furnace length of 30 cm.

[0043] The temperature of the tension annealing furnace, as shown in FIG. 2, gives the most important influence on the magnetic properties. The temperature is set to 530 C. which is 20 C. bellow the crystallization temperature of the amorphous alloy. If the wire temperature exceeds 550 C., the magnetic properties become poor remarkably. It is important to keep the temperature below 550 C. The conveyance speed is 1 m per minute and the holding time in the furnace is 18 seconds. The net length of the wire heated up to the designated temperature of 530 C. is reduced as much as possible with a result that the elongation and the change of tensile stress of the wire become small.

[0044] A large tensile stress of the wire in tension annealing treatment can reduce hysteresis of the wire but increase the anisotropy field. The tension annealing is carried out at a designated tensile stress of 200 MPa and designated temperature of 530 C. and results in magnetic properties such as a coercive force of 0.01 Oe and an anisotropy field of 1 Oe wherein smaller coercive means smaller hysteresis. The continuous operation of 1 km wire can be carried out without wire breakage when the values of tension and conveyance speed are controlled to be equal to the designated values with adjusting tension and conveyance speed using the tension roller 13 placed upstream of the furnace and the post heat treatment capstan 43. The value during operation is calculated by the tension measured by the tension measuring device 31 and the wire diameter measured by the wire diameter measuring device 21.

[0045] A size measuring device 21 with magnetic impedance are used to measure diameter of from 10 m with accuracy of 0.5 m. The strain gage type of tension measuring device 31 is used to measure and control a tensile stress of 2000 MPa with accuracy of 1 MPa. The measured values are input in the control unit where they are recorded corresponding to the designated distance from the start of wire drawing and the designated distance inserted into the furnace is treated at the time with the temperature of 530 C. and tensile stress of 200 MPa.

[0046] The interval between the supply bobbin 11 and the wind-up bobbin 51 becomes as long as 4 m because the wire diameter measuring device 21 and the tension measuring device 31 are installed. The problem is solved by dividing the long interval into four parts consisting of the wire supply part 10, the measuring parts 20, 30, the furnace 40 and the winding up part 50 which have each a capstan 14, 22, 43, 52 and a tension roller 13 between capstans. By controlling the tension and speed at each part controlled by the capstan and tension roller placed, the differences in wire conveyance speed and the friction between tension roller and wire are dissolved and continuous operation of 1 Km at the speed of 1 m per minute can be performed without wire breakage.

[0047] As shown above in the present example, the magnetic properties of the magnetic wire is improved from 5 Oe to 1 Oe in the anisotropy field, and from 0.1 Oe to 0.01 Oe in coercive force by operating with a magnetic wire temperature of 530 C., a tensile stress of 200 MPa and a conveyance speed of 1 m per minute. Therefore, the magnetic sensitivity of GSR sensor strongly dependent on the magnetic properties of the amorphous wire is improved largely and it can be developed into a lot of applications.

Example 2

[0048] The second example of the present invention applied to a glass coated amorphous wire 2 with an inner metal diameter of 10 m and an outer diameter of 12 m including coated glass is the first example further which is equipped with a type of a wire diameter measuring device to measure the inner diameter of the metal part and the outer diameter of the wire covered with insulating material. The tensile stress is calculated from the net tension only loaded to the wire metal part which is divided by metal diameter.

Example 3

[0049] The third example is related to a method carried out using the furnace described in the first example. This method requests to measure the diameter, the tensile stress, the temperature and the conveyance speed using the wire diameter measuring device 21, the tension measuring device 31, the temperature measuring device 42, and the capstans 14,22, 43, 52 respectively and to perform tension annealing within the temperature range of from 450 C. to 500 C., the tensile stress of from 50 MPa to 250 MPa and the conveyance speed of from 1 m to 10 m per minute in the furnace. This method is implemented as a program of the control unit 60.

INDUSTRIAL APPLICABILITY

[0050] As mentioned above, the present invention directed to a tension annealing furnace and a method therefor is useful in improving the magnetic performance of GSR censor through improving the magnetic properties of magnetic wire.

REFERENCE SIGNS LIST

[0051] 1: a heat treatment equipment of magnetic wire

[0052] 2: magnetic wire

[0053] 10: wire supply part

[0054] 11: supply bobbin

[0055] 12: wire reel

[0056] 13: tension roller

[0057] 14: supply capstan

[0058] 20: wire diameter measurement part

[0059] 21: wire diameter measuring device

[0060] 22: post diameter measurement capstan

[0061] 30: wire tension measurement part

[0062] 31: tension measuring device

[0063] 40: tension annealing furnace

[0064] 41: furnace for tension annealing treatment

[0065] 42: temperature measuring device

[0066] 43: capstan after heat treatment

[0067] 50: wire winding up part

[0068] 51: bobbin for winding up

[0069] 52: winding up capstan

[0070] 60: control unit

[0071] 61: input unit of sensor signals (dimension, tension, furnace temperature)

[0072] 62: control instructions (capstans, tension rollers)