JP2001009576A - Metallic material jointing method, and high frequency induction heating coil used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic material jointing method wherein a butt part is accurately heated to a desired jointing temperature during liquid phase diffusion jointing and a jointing product having a proper mechanical strength can be obtained, and also provide a high frequency induction heating coil used for it. SOLUTION: In this jointing method, end faces of metallic materials 2 and 3 are butted via an insert material 1, a the butt part 4 is heated to the temperature above the melting point of the insert material 1 for performing liquid phase diffusion jointing. In this case, a high frequency induction heating coil 10 is used as a heating means, and a coil width center 12 is positioned on a jointing face 8 of the metallic material. Also, a light condensing axial line 7 in an optical system is positioned at the position which is descentered from the coil width center 12 in the coil width direction. The surface temperature of the butt part 4 is measured by a radiation temperature meter 6 mounted to the high frequency induction heating coil 10, so that the heating temperature of the butt part 4 is controlled on the basis of the measured temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of inserting an insert material between end faces of a metal material to be joined such as a tube material and joining by liquid phase diffusion joining and a high frequency induction heating coil used for the method.

[0002]

2. Description of the Related Art Conventionally, as a method of joining steel pipes such as oil country tubular goods for oil drilling, end faces of steel pipes to be joined are butt-joined via an insert material. A liquid phase diffusion bonding method is known in which a melted insert material is heated to a temperature equal to or lower than the melting point of the steel pipe to diffuse the melted insert material to the end face of the steel pipe.

As a means for heating the butted portion, as shown in the conventional example of FIG. 2, an annular butted portion 4 of steel pipes 2 and 3 joined via an insert material 1 is concentrated and used. Since high-speed heating can be performed, a high-frequency induction heating coil 5 is often used. The surface temperature of the butt 4 is measured by a radiation thermometer 6 for controlling the heating temperature of the butt 4, and based on the measured value. The amount of electric power supplied to the high-frequency induction heating coil 5 is controlled.

However, in the joining of the steel pipes by the above-described apparatus shown in FIG. 2, the actual heating temperature of the butting portion 4 varies considerably at each joining, and the insert material 1 is shifted due to the deviation from the joining temperature which is the control target temperature. In this case, there is a problem that the liquid phase diffusion becomes excessive or insufficient, and the mechanical strength of the joined portion after joining becomes insufficient.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, and can accurately heat a butt portion to a desired joining temperature at the time of liquid phase diffusion joining, and can obtain appropriate mechanical strength. It is an object of the present invention to provide a metal material joining method capable of obtaining a joined product having the same and a high-frequency induction heating coil used for the method.

[0006]

Means for Solving the Problems In order to achieve the above object, the present inventors have observed and studied the behavior of the butt portion at the time of joining in detail, and as a result, as shown in FIG.
The insert material 1 melted by heating is intermittently extruded onto the end surfaces of the steel pipes 2 and 3 as a convex part 1a in the form of a droplet, and the focusing axis 7 of the optical system of the radiation thermometer 6 is ,
3 is located at the same position as the joint surface 8, the projection 1 a easily appears in the spot-like temperature measurement range of the radiation thermometer 6. When the projection 1 a appears, the surface of the steel pipe and the liquid projection 1 a The measurement temperature of the radiation thermometer 6 becomes inaccurate due to the difference in emissivity from the measurement result, and as a result of the temperature control based on this measurement temperature, a difference between the actual heating temperature and the junction temperature is found.
Based on this knowledge, the present invention has been completed.

That is, according to the first aspect of the present invention, the end faces of metal materials to be joined are butted via an insert material, and the butted portion is heated to a temperature equal to or higher than the melting point of the insert material to perform liquid phase diffusion bonding. In the joining method, a high-frequency induction heating coil is used as the heating means, and the center of the coil width of the high-frequency induction heating coil is positioned at the joining surface position of the metal material, and is eccentric in the coil width direction from the center of the coil width. The surface temperature of the butting portion is measured by a radiation thermometer attached to the high-frequency induction heating coil with the optical axis of the optical system positioned at the position, and the heating temperature of the butting portion is determined based on the measured temperature. It is a metal material joining method characterized by controlling.

In the present invention, the bonding surface position of the metal material means the end surface position of the metal material because the thickness of the insert material is as thin as several tens of μm and can be ignored. The reason why the center of the coil width is located at the above-mentioned joint surface position is that the normal high-frequency induction heating coil is set in the axial direction with respect to the metal material (for example, ± 0.
5 mm).

According to the first aspect of the present invention, first, the high-frequency induction heating coil heats the butted portion by positioning the center of the coil width at the joining surface position of the metal material. The material can be heated with a symmetrical temperature distribution centered on the insert material without being biased, and the melted insert material is diffused evenly between the two metal materials, and good diffusion bonding is performed. The focusing axis of the optical system of the radiation thermometer is
Since it is located at a position eccentric in the coil width direction from the coil width center located at the bonding surface position, the insert material melted when the butt portion is heated is extruded, and a droplet-shaped convex portion is formed on the surface of the bonding surface position. Even when extruded, the appearance of the projections within the spot-like temperature measurement range of the radiation thermometer can be suppressed to a small amount or can be prevented, and the radiation thermometer can accurately measure the surface temperature of the metal material. It is possible to accurately heat the butted portion to a desired joining temperature based on the measured value,
By performing good liquid phase diffusion bonding without excess and deficiency, a bonded product having appropriate mechanical strength can be obtained.

According to a second aspect of the present invention, the end faces of the metal materials to be joined are butted via an insert material, and the butted portion is heated to a temperature equal to or higher than the melting point of the insert material to perform liquid phase diffusion bonding. A high-frequency induction heating coil for use in a joining method, wherein a radiation thermometer is mounted with a converging axis of an optical system positioned at a position eccentric from a coil width center in a coil width direction. .

According to the second aspect of the present invention, the same operational effects as those of the first aspect can be obtained by using the center of the coil width at the position of the joining surface of the metal material.

In the present invention, the eccentricity of the converging axis of the optical system of the radiation thermometer from the center of the coil width in the first and second aspects can have various values. Is less than 1 mm, the center of the coil width,
Therefore, since it is too close to the joining surface of the metal material, the convex portion of the melted insert material easily appears within the spot-like temperature measuring range of the radiation thermometer, and when the eccentric amount exceeds 5 mm, the eccentricity exceeds the joining surface portion. The temperature control is performed to measure the surface temperature of the metal material at a position where the temperature tends to decrease due to heat transfer loss or the like outside the butted portion and to maintain the portion at the set temperature. Since overheating is likely to occur, the eccentricity is 1 to 3 as described in claim 3.
It is particularly preferred that the configuration be 5 mm.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the drawings, the same parts as those in FIGS. 2 and 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.
Reference numeral 10 denotes a high-frequency induction heating coil that surrounds the butted portion 4 of the steel pipes 2 and 3, has a cooling water flow passage 11 therein, and centers the coil width 12 on the position of the joint surface 8 of the steel pipes 2 and 3 (= steel pipe 2). , 3). Reference numeral 6 denotes a radiation thermometer, which is mounted on the high-frequency induction heating coil 10 in such a manner that the converging axis 7 of the optical system is eccentric from the coil width center 12 by δ in the coil width W direction and oriented in the coil diameter direction. .

Reference numeral 13 denotes a temperature control device, which is a measurement temperature t output from the radiation thermometer 6 and a junction temperature set value T set by the setting unit 14.
Is output to the high-frequency power supply device 15 and the high-frequency power amount P for the high-frequency induction heating coil 10 is supplied.
Is adjusted to control the heating temperature of the butting portion 4.

Using the apparatus having the above structure, the insert material 1
A pressurizing device (not shown) applies a pressing force to the steel pipes 2 and 3 whose end faces are abutted through each other, and the butted portion 4 is heated by the high-frequency induction heating coil 10 so that the butt 4 is at or above the melting point of the insert material 1 and the steel pipes 2 and 3 The liquid phase diffusion bonding is performed by heating to a bonding temperature lower than the melting point. During this heating, even if the insert material 1 is melted and extruded intermittently onto the end surfaces of the steel pipes 2 and 3 as droplet-shaped convex portions 1a (see FIG. 3), the converging axis of the radiation thermometer 6 7 is located at a position eccentric from the joining surface 8 by δ in the coil width direction.
m), the amount of appearance of the convex portion 1a decreases or becomes zero, and the radiation thermometer 6 accurately measures the surface temperature of the steel pipe 2 or 3 (the steel pipe 2 in FIG. 1), and the measured temperature t Since the butting portion 4 can be accurately heated to the joining temperature T based on this, the liquid-phase diffusion bonding can be performed without excess and deficiency, and proper mechanical strength of the joined portion can be obtained.

After the heating, the butting portion 4 is cooled by a conventional method. In the cooling step, the cooling amount may be controlled based on the temperature measured by the radiation thermometer 6. it can.

[0017]

〔conditions〕

○ Steel pipe (material to be joined): Carbon steel pipe STPG41 for pressure piping
0 (JIS Z3454) Outer diameter = 216.3 mm, wall thickness = 10.3 mm Insert material: Material = BNi-3 (JIS Z326)
5), thickness = 35 μm ○ Bonding conditions: bonding temperature = 1300 ° C., holding time = 60
Second, pressure = 3MPa, bonding surface roughness = Rmax25
μm Radiation thermometer: Silicon photodiode radiation thermometer,
Temperature measuring range spot diameter = 2mm

[0018]

[Table 1]

From the results shown in Table 1, it can be seen that, in comparison with the comparative example corresponding to the conventional method shown in FIG. It can be seen that the mechanical strength was improved.

The present invention is not limited to the above example. For example, the amount of eccentricity (of the converging axis) of the radiation thermometer may be a value other than the above, and the power control system for the high frequency induction heating coil may be used. May be other than the above. The present invention can be widely applied to joining of various metal materials such as pipes and rods other than oil country tubular goods.

[0021]

As described above, according to the present invention,
The surface temperature of the metal material was measured with a radiation thermometer by positioning the light-collecting axis at a position eccentric in the coil width direction of the high-frequency induction heating coil from the joint surface of the metal material.
The appearance of the protrusion of the molten insert material within the spot-like temperature measurement range of the radiation thermometer is suppressed, the surface temperature of the metal material is accurately measured, and the butt portion is accurately heated to the joining temperature. Good liquid phase diffusion bonding can provide a bonded product having appropriate mechanical strength.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a bonding apparatus showing an example of an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a conventional bonding apparatus.

FIG. 3 is an enlarged schematic view of a main part of FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insert material, 2 ... Steel pipe, 3 ... Steel pipe, 4 ... Butt joint, 6 ... Radiation thermometer, 7 ... Condensing axis line, 8 ... Joint surface, 10
... High frequency induction coil, 12 ... Coil width center, 13 ... Temperature control device.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) H05B 6/06 H05B 6/06 // G01N 33/20 G01N 33/20 P (72) Inventor Shigeyuki Inagaki Nagoya Nagoya 3-9-111, Tenpakucho, Minami-ku, Daido Special Steel Tenpakuso 205 F term (reference) 2G055 AA03 AA12 BA14 FA01 3K059 AB22 AC33 AD04 4E067 AA02 AD02 BA05 BH02 CA03 CA05 EC06

Claims (3)

[Claims] 1. A joining method for joining liquid metal diffusion joints by joining end surfaces of metal materials to be joined with each other via an insert material and heating the butted portion to a temperature equal to or higher than the melting point of the insert material. A high-frequency induction heating coil is used as a means, and the center of the coil width of the high-frequency induction heating coil is located at the bonding surface position of the metal material, and the light-collecting axis of the optical system is located at a position eccentric from the center of the coil width in the coil width direction. Metal surface characterized by measuring a surface temperature of the butt portion by a radiation thermometer attached to the high-frequency induction heating coil and controlling a heating temperature of the butt portion based on the measured temperature. Material joining method. 2. High-frequency induction heating used in a joining method for performing liquid phase diffusion joining by joining end faces of metal materials to be joined with each other via an insert material and heating the butted portion to a temperature equal to or higher than the melting point of the insert material. A high-frequency induction heating coil, wherein a radiation thermometer is mounted on a coil, with a light collecting axis of an optical system positioned at a position eccentric from a coil width center in a coil width direction. 3. The method according to claim 1, wherein the eccentricity of the optical axis of the optical system of the radiation thermometer from the center of the coil width is 1 to 5 mm. .