JP2004193033A - Electric heating method of conductive rod-shaped member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make temperature of a whole part of a longitudinal rod-shaped member heated by electric heating almost uniform. <P>SOLUTION: A construction that realizes such a temperature distribution on the rod-shaped member 2 that the temperature at a central part of the rod-shaped member 2 is higher than that at both end parts when electrically heating the rod-shaped part 2 by making first electrodes 9<SB>1</SB>contact with respective end parts of the conductive rod-shaped member 2; and that the temperature at both end parts of the rod-shaped member 2 is higher than that at the central part when electrically heating the rod-shaped member 2 by using second electrodes 9<SB>2</SB>; is provided, and a first process of electrically heating the rod-shaped member 2 by using the first electrodes 9<SB>1</SB>and a second process of electrically heating the rod-shaped member 2 by using the second electrodes 9<SB>2</SB>are processed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for electrically heating a conductive rod-shaped member, and more particularly to a method for heating electrodes by pressing electrodes at both ends of the conductive rod-shaped member and supplying current to the rod-shaped member.
[0002]
[Prior art]
Conventionally, a copper electrode is used in this type of energization heating method (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP-A-8-264260 ([0015], Table 1)
[0004]
[Problems to be solved by the invention]
For example, when copper electrodes are pressed against both ends of a rod-shaped member made of an Al alloy, and the rod-shaped members are energized and heated, the copper electrodes generate less Joule heat and a smaller temperature rise than the rod-shaped members. Since heat is transmitted from the rod-shaped member, the rod-shaped member has a temperature distribution in which the temperature is higher at the center than at both ends of the rod-shaped member. However, there is a problem that it cannot be made uniform over the entire area.
[0005]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an electric heating method in which the temperature of a conductive rod-shaped member caused by heating can be made substantially uniform over its entire length.
[0006]
According to the present invention, in order to achieve the above object, according to the present invention, electrodes are pressed against both ends of a conductive rod-shaped member, and when the rod-shaped member is electrically heated, the rod-shaped member is energized as a first electrode. When the rod-shaped member is made to exhibit a temperature distribution such that the temperature of the rod-shaped member is higher at the center than at both ends thereof when heated, and when the rod-shaped member is electrically heated as the second electrode , A rod-shaped member having a temperature distribution at both ends thereof higher than that at the center thereof is prepared, and the rod-shaped member is electrically heated using the first electrode. There is provided a method for electrically heating a conductive rod-shaped member, the method comprising performing a first step and a second step of electrically heating the rod-shaped member using the second electrode.
[0007]
When the above-described means is adopted, a temperature distribution appears in the rod-shaped member in the first step such that the temperature is higher in the central portion than in the both ends thereof. In the secondary process, the rod-shaped member is heated by the second electrode so that the temperature rise at both ends is greater than the temperature rise at the center thereof. It can be made substantially uniform over its entire length.
[0008]
In this case, when the first step is performed using the second electrode, a temperature distribution appears in the rod-shaped member such that the temperature is higher at both ends than at the center. Therefore, if the temperature at the center is raised to a predetermined temperature in preparation for the secondary process, the temperature at both ends exceeds the target temperature, adversely affecting the material properties at both ends and melting both ends. Occurs.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
In the electric heating device 1 shown in FIGS. 1 and 2, a conductive and hollow rod-shaped member 2 is supported at both ends thereof by a heat and electric insulating support member 3 such as ceramics. Each support member 3 has a recess for receiving the outer peripheral surface of the rod-shaped member 2. First and second energizing units U ₁ and U ₂ are arranged at both ends of the rod-shaped member 2, respectively. Each of the first and second energizing units U ₁ and U ₂ has a U-shaped support frame 4, and two pneumatic (or hydraulic) working cylinders 7 ₁ , 7 on the upper plate 5 and the lower plate 6 of the support frame 4, respectively. 7 ₂ is mounted side by side in the axial direction of the rod-like member 2. The piston rod 8 of each of the working cylinders 7 ₁ and 7 ₂ penetrates the upper and lower plates 5 and 6 and is located at the center of the rod-shaped member 2 in the _first and second energizing units U ₁ and U ₂ . both working cylinder 7 of the _first electrode 9 ₁ respectively to the piston rod 8 is attached to opposite I, also both hydraulic cylinders 7 ₂ of the piston rod facing each be in both end faces of the rod-like member 2 8 the second electrode 9 ₂ are each attached to. Each of the first and second electrodes 9 ₁ and 9 ₂ has a concave arc surface 10 so as to be in close contact with the outer peripheral surface of the rod-shaped member 2.
[0010]
In the first energizing unit U _1, the leads 13 extending from the lead wire 11 and both the second electrodes 9 ₂ extending from both the first electrode 9 ₁ is focused on one lead wire 14, the lead 14 Is connected to one terminal of the power supply 15. Also in the second energizing unit U _2, leads 17 extending from the lead wire 16 and both the second electrodes 9 ₂ extending from both the first electrode 9 ₁ is focused on one lead wire 18, the lead wire Reference numeral 18 is connected to the other terminal of the power supply 15.
[0011]
The rod-shaped member 2 is made of an Al alloy, for example, a 5000 series Al alloy, and has a conductivity of 1.9 × 10 ⁷ S / m.
[0012]
First electrode 9 ₁ Cu alloy, for example, tough pitch copper (JIS C1100) is configured from, its conductivity is a 5.8 × 10 ⁷ S / m, higher than that of the rod-like member 2. In this case, by operating the respective operating cylinders ₇₁ each first electrode 9 ₁ respectively pressed against the opposite ends of the rod-like member 2 by heating it to energization from the power supply 15 to the rod-like member 2, the rod As shown in FIG. 3, the member 2 has a temperature distribution in which the temperature is higher at the center than at both ends.
[0013]
The second electrode 9 ₂ steel, for example, is constructed from rolled steel for general structure (JIS SS400), a conductivity of a 6.0 × 10 ⁶ S / m, significantly than that of the rod-like member 2 Low. In this case, by operating the respective working cylinder 7 _2, each of the second electrodes 9 ₂ respectively pressed against the opposite ends of the rod-like member 2, is energized from the power supply 15 to the rod-like member 2, heating it, the As shown in FIG. 4, the rod-shaped member 2 has a temperature distribution in which both ends are hotter than the center thereof. This is for the following reasons. That is, the second electrode 9 ₂ the conductivity is low, it calorific value of itself is a temperature rise large compared to the rod-like member 2 to become larger than the Joule heat of the rod-like member 2, the temperature difference the is the temperature of the heat conduction occurs both ends of the second electrode 9 ₂ the rod-like member 2 is higher than the temperature of the central portion.
[0014]
In light of the points of the hits the energized heating rod-like member 2, and the primary step of electrically heating the rod-like member 2 by using the first electrode 9 _1, the rod-shaped member with the second electrode 9 ₂ And a secondary step of heating by heating.
[0015]
If such a means is adopted, in the first step, a temperature distribution appears in the rod-shaped member 2 such that the temperature is higher at the center than at both ends thereof. The second electrode 9 ₂ is a second step, the rod-shaped member 2 is, toward the rising temperature case of both end portions than raising the temperature if the central portion is heated so that the larger rod-shaped member by heating 2 can be made substantially uniform over its entire length.
[0016]
〔Example〕
(1) A rod-shaped member 2 having the same material as described above, having an outer diameter of 90 mm, an inner diameter of 83 mm, and a length of 1000 mm is prepared. As shown in FIG. 3 supported. The set respectively the pressing area relative to the rod-like member 2 by all first electrodes 9 ₁ to 1500 mm ^2, also it by all the second electrodes 9 ₂ to 3000 mm ^2. Further, the target temperature of the rod-shaped member 2 by heating was set to 500 ° C.
[0017]
(2) As shown in FIG. 5 (a), actuates the respective hydraulic cylinders 7 _1, 20000 A each first electrode 9 ₁ the rod-like member 2 from the power supply 15 to the respective pressure contact with the both end portions of the rod-like member 2 Was passed. In this case, from the start of heating to the time when the temperature of the rod-shaped member 2 reached 150 ° C., the temperature of the member 2 rose substantially constant over its entire length, as shown by the line a in FIG.
[0018]
(3) When the temperature at both ends is approximately 200 ° C. and the temperature at the center reaches approximately 300 ° C. as shown by the lines b and b in FIG. the cylinder 7 ₁ is operated, to separate the respective first electrodes 9 ₁ from both ends of the rod-like member 2, also actuates the respective hydraulic cylinders 7 _2, each of the second electrodes 9 ₂ at both ends of the rod-like member 2 The electrodes were pressed against each other, and a current of 20,000 A was passed from the power source 15 to the rod-shaped member 2.
[0019]
As a result, as shown in FIG. 6 and lines c and d, the rod-shaped member 2 is heated so that the temperature rise at both ends is greater than the temperature rise at the center, and finally the rod-shaped member 2 is heated. The temperature of the both ends of the member 2 is increased by approximately 300 ° C., while the temperature of the central portion is increased by approximately 200 ° C., and the temperature of the member 2 is approximately 500 ° C. over its entire length as shown by a line e in FIG. Reached.
[0020]
When switching the first electrode 9 ₁ and the second electrode 9 _2, when in the state in which the first electrode 9 ₁ as shown in FIG. 7 (a) is pressed against the rod-like member 2, FIG. 7 ( each second electrode 9 ₂ as shown in b) pressed against the rod-shaped member 2, thereafter, be made to separate the respective first electrodes 9 _1, as shown in FIG. 7 (c) from the rod-like member 2 Good.
[0021]
【The invention's effect】
According to the present invention, by employing the above-described means, the temperature of the conductive rod-shaped member due to electric heating can be made substantially uniform over its entire length.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an electric heating device.
FIG. 2 is a sectional view taken along line 2-2 of FIG.
FIG. 3 is a graph showing a temperature distribution of a rod-shaped member when a first electrode is used.
FIG. 4 is a graph showing a temperature distribution of a rod-shaped member when a second electrode is used.
FIG. 5 is an explanatory diagram showing an example of a state in which power is supplied to a rod-shaped member.
FIG. 6 is a graph showing a change in temperature distribution of a rod-shaped member when the first and second electrodes are used.
FIG. 7 is an explanatory view showing another example of a state of energizing the rod-shaped member.
[Explanation of symbols]
2. Rod-shaped members 7 ₁ , 7 ₂ Working cylinders 9 ₁ , 9 ₂ First and second electrodes 15 Power supply

Claims (1)

Each electrode at both ends of the conductive rod-like member (2) in pressure contact, contact to electrically heating the rod-like member (2), as the first electrode (9 _1), the rod-like member (2) when energized heated, its rod-like member (2), those towards the center portion to revealing the temperature distribution such that the temperature higher than both end portions thereof, also as the second electrode (9 _2), wherein When the rod-shaped member (2) is energized and heated, the rod-shaped member (2) is prepared so as to exhibit a temperature distribution such that the temperature at both ends is higher than that at the center thereof. a primary step of electrically heating the rod-like member (2) with a first electrode (9 _1), 2 energized heating the rod-like member (2) with the second electrode (9 ₂₎ order And heating the conductive rod-shaped member.

Images