JPH1046355A - Treatment for surface of metallic tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating a metallic tube capable of setting the thickness of a build-up welding layer to a desired one and capable of easily and securely forming a durable metallic layer of prescribed components subjected to metallurgical joining extremely small in the rate of dilution at the time of forming a durable metallic layer such as a wear resistant layer, a corrosion resistant layer of the like on the inside and outside surfaces of a metallic tube to be exposed to severe wear environments or corrosive environments by welding. SOLUTION: As for the method for treating the surface of a metallic tube, at the time of forming a durable metallic layer 2 obtd. by metallurgical joining on the surface of a metallic tube 1, the metallic tube 1 is arranged in the longitudinal direction, the surface is coated with a granular durable metallic material 2 mixed with a binder, a coil 3 connected to AC power is arranged around the metallic tube 1, and power is supplied to the coil 3. Then, by moving at least either the metallic tube 1 or the coil 3 to the axial direction of the metallic tube 1, the metallic tube 1 and the granular durable metallic material 2 are heated by induction heating to melt the granular durable metallic material 2, and the melted durable metallic material 2 is welded on the surface of the heated metallic tube 1 to form the durable metallic layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a surface of a metal tube, and more particularly to a method for imparting excellent durability to the inside and outside surfaces of a metal tube exposed to a wear environment or a corrosive environment in various industries. It relates to improvement of surface treatment method.

[0002]

2. Description of the Related Art In order to transport raw materials and product materials in the manufacturing industry such as steel, cement, etc., when they are transported through metal pipes using a so-called pipeline facility or when they are pressure-fed, such materials are used. The eroded portion, whatever its shape, is exposed to a wear environment. In the chemical, petrochemical, water treatment, and power generation industries, there are corrosive environments and high-temperature heating environments due to chemical reactions and a wide variety of weakly acidic atmospheres. There is always the risk of heat loss.

[0003] As a measure against such abrasion or corrosion, a special material corresponding to the purpose of countermeasures generally called cladding is mechanically or mechanically applied to the inner or outer surface of the metal pipe.
Metallurgically adhered or welded. Thus, the most widely used welding method for metallurgical joining is the overlay welding method. In the case of forming a wear-resistant layer, arc welding using a welding rod or a welding wire as a filler metal is used. In general, even when forming a corrosion-resistant layer, a predetermined corrosion-resistant material can be melted and welded by an arc welding method, a gas welding method, or a plasma powder overlay method. Explosive bonding or rolling and crimping methods are sometimes used for cladding, which has a large number of market demands, such as stainless steel materials and titanium materials, but the types of cladding materials are limited.

When the arc welding method is used to form the wear-resistant layer, the heat input necessarily inevitably causes penetration into the metal tube side as the base material, thereby diluting the wear-resistant material. However, there is a problem that a chemical component is reduced due to each dilution ratio according to each welding condition, and furthermore, wear-resistant overlay welding materials are generally high in welding crack susceptibility. It should be welded by welding, and multi-layer welding requires complicated work in terms of thermal management and also in the method of construction, and is not preferable.

However, in one-pass, single-layer welding, the wall thickness is often limited to 3 to 5 mm from the principle thereof, and the existence and fluctuation of the dilution ratio stabilize the target wear resistance. Not only is it difficult, but also the required wear-resistant layer is extremely diluted near the inner and outer surfaces of the base metal tube, and is further limited to a thickness range of 3-5 mm, with a thinner layer thickness and When a large layer thickness is required, it is extremely difficult and requires complicated means.

On the other hand, when forming a corrosion-resistant layer, unlike a wear-resistant layer, a layer thickness such as a wear-resistant layer is not required in design to prevent static corrosion wear and cracking.
A layer thickness of 1 mm may be satisfactory. However, the corrosion-resistant layer has a small variation error range of the target component, the diluted layer is not considered as a corrosion-resistant layer, and the component value required in the conventional overlay welding method in which the component value varies in the thickness direction of the layer is one. Despite being about 2 mm, 5 to 3
There is a variety of problems in that a buildup layer of about 7 mm must be formed, an expensive special alloy material must be welded in a larger amount than necessary, and the construction cost must be increased.

When the base material is a metal tube, as shown in FIGS. 19 and 20, the metal tube (a) is arranged laterally on a pair of receiving rollers (b) and connected to a motor. While rotating the metal tube (a) by the rotation drive member (c), the inner and outer surfaces of the metal tube (a) are welded by a plasma powder overlay welding method, an automatic TIG welding method, and a MIG welding method using a torch (d). For example, overlay welding is performed while feeding powder or filler rod or wire of a predetermined material component. However, in the case of a metal pipe having a length of about 1 m or more, the nozzle swings and it is difficult to weld properly. In addition, there is a lower limit on the inner diameter when installing on the inner surface of metal, and a diameter length of about 80 mm or more in the case of plasma welding and about 150 mm or more in the case of MIG welding, and it can not be done with less than that There is.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been developed to solve the above-mentioned various problems in the prior art, and has been developed to solve the problems of the metal pipes exposed to severe wear and corrosive environments. When welding and forming a durable metal layer such as an abrasion-resistant layer or an anti-corrosion layer on the inner and outer surfaces, a predetermined component that can be set to a desired thickness and has a metallurgical bond with a very small dilution rate It is an object of the present invention to provide a surface treatment method for a metal tube that can easily and reliably form a durable metal layer.

[0009]

In order to solve the above-mentioned problems and to achieve the object, the present invention provides a method for forming a durable metal layer formed by metallurgical bonding on the inner surface of a metal tube. A tube is arranged vertically, a powdery and durable metal material mixed with a binder is applied to the inner surface of the tube, and a coil connected to an AC power supply is arranged around the metal tube to energize the coil. Along with moving at least one of the metal tube and the coil in the axial direction of the metal tube, the metal tube or the granular durable metal material is heated by induction heating to melt the granular durable metal material, An object of the present invention is to provide a surface treatment method for a metal tube, characterized in that the molten durable metal material is welded to an inner surface of a heated metal tube to form a durable metal layer.

In order to solve the above-mentioned problems and to achieve the object, the present invention provides a method for forming a durable metal layer formed by metallurgical bonding on the inner surface of a metal tube. After applying a powdery and durable metal material mixed with a binder to the inner surface thereof, insert a core tube coated with a release material on the outer surface into the metal tube, and place the metal tube around the metal tube. A coil connected to an AC power supply is arranged and energized, and at least one of the metal tube and the coil is moved in the axial direction of the metal tube to induce the metal tube or the powdery and durable metal material. A metal tube formed by heating to melt the powdery durable metal material, and welding the molten durable metal material to an inner surface of the heated metal tube to form a durable metal layer; The surface treatment method of the present invention is provided.

[0011] Further, in order to solve the above-mentioned problems and achieve the object, the present invention provides a method for forming a durable metal layer formed by metallurgical bonding on the outer surface of a metal tube. And a powdery and durable metal material mixed with a binder is applied to the outer surface thereof. A coil connected to an AC power supply is arranged around the metal tube to energize the coil, and the metal tube is energized. By moving at least one of the coil and the coil in the axial direction of the metal tube, the metal tube or the powdery and durable metal material is heated by induction heating to melt the powdery and durable metal material. An object of the present invention is to provide a surface treatment method for a metal tube, comprising forming a durable metal layer by welding a conductive metal material to an outer surface of a heated metal tube.

Further, in order to solve the above-mentioned problems and to achieve the object, the present invention provides a method for forming a metal tube by using a metallurgical joint on the outer surface of a metal tube. Orientation, and apply a powdery and durable metal material mixed with a fixing agent to the outer surface thereof, and around the metal tube,
A short-tube mold for preventing the coating material from flowing down and forming a smooth coating layer is fitted, and a coil connected to an AC power supply is disposed and arranged outside the mold. While energizing the metal tube, at least one of the metal tube and the mold surrounding the coil is moved in the axial direction of the metal tube,
By rotating the metal tube about its axis, the metal tube or the powdery and durable metal material is heated by induction heating to melt the powdery and durable metal material. An object of the present invention is to provide a method for treating a surface of a metal tube, wherein a material is welded to an outer surface of a heated metal tube to form a durable metal layer. In the present invention, “granular” refers to “a powder alone”, “a granule alone”, and “a mixture of a powder and a granule”.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the present invention, and the present invention is applied to a wear environment. A metal pipe 1 to be exposed is vertically arranged at a construction site so as to be vertically movable, and a powder material 2 of a wear-resistant material mixed with a glass-based adhesive is applied to an inner surface of the metal pipe 1 to a predetermined thickness. At a predetermined position around the tube 1, the coil 3 connected to an AC power supply is disposed so as to surround the coil 3, the coil 3 is energized, and the metal tube 1 is moved downward in the axial direction, thereby inductively heating the metal tube 1. After the coating powder material 2 is melted by the heat energy of the metal tube 1 and welded to the inner surface of the metal tube 1,
When the descent of the metal tube 1 and the energization of the coil 3 are stopped,
The deposited metal solidifies to form a wear-resistant layer 4 on the inner surface of the metal tube 1. In addition, a small amount of a slag-making agent (slag component) may be added for smooth welding.

The formation of the wear-resistant layer 4 is based on the principle that the powder material 2 is melted by the effect of heat energy on the inner surface of the induction-heated metal tube 1 due to the relationship between current carrying capacity and time. 1 is performed by welding and solidifying on the inner surface.

Next, an example corresponding to the first embodiment of the present invention will be described. (Embodiment) For example, FIG. 1 shows a case where a wear-resistant layer 4 is formed on the inner surface of a metal pipe 1 for transferring and pumping various materials in the steel and cement industries by using a powder material 2 as a wear-resistant material. The surrounding coil 3 shown in FIG.
An embodiment in which a high-frequency power source of KHZ · 30 KW is connected and energization processing is performed is described below. Metal tube: SGP-100A, outer diameter φ114.3mm, wall thickness 4.5, length
1000 mm, lowering speed 50 mm / min powder material; iron-based powder 50% + tungsten carbide (W ₂ C) 50% (particle size -250 + 60 microns) coating thickness; 4 mm high-frequency oscillator condition; coil load voltage: 360 V, coil load Under the conditions described above, a wear-resistant metal pipe for transfer and pressure feeding was obtained, which was uniformly provided with a wear-resistant layer 4 having a welded layer thickness of 2 mm on the inner surface under the above conditions. Performance of wear-resistant metal pipes for transfer and pumping; service life was about 20 times or more as compared with conventional SGP raw pipes, and about 15 times or more as compared with hardened pipes.

FIG. 2 shows a second embodiment of the present invention. The difference from the first embodiment is that the metal tube 1 is not moved and the coil 3 is moved to the first position. Only at the point where the metal tube 1 was moved upward in the direction of the arrow at the same speed as the moving speed of the metal tube 1 in the embodiment, other conditions were the same as those of the first embodiment. The performance of the metal tube is the same as in the first embodiment. Therefore,
The same means are denoted by the same reference numerals.

FIG. 3 shows a third embodiment of the present invention. The difference from the first and second embodiments is that both the metal tube 1 and the coil 3 are simultaneously placed in opposite directions. Is moved at the same speed to
The metal tube 1 is moved downward in the direction of the arrow and the coil 3 is moved.
Is moved upward in the direction of the arrow, and is therefore different from the example of the first embodiment only in the following point. Therefore, the same means are denoted by the same reference numerals.

(Examples) In an example corresponding to the third embodiment, the metal tube 1, the powder material 2, the coating thickness of the powder material, the high-frequency oscillator conditions of the coil 3, the welding layer of the wear-resistant layer 4, and the like. Since the thickness and the like are the same as those in the example of the first embodiment, the same reference numerals are given to the same means, but in this embodiment, both the metal tube 1 and the coil 3 are moved in opposite directions. Since the means for moving at the same time is employed, the processing time can be reduced to about half.

FIG. 4 shows a fourth embodiment of the present invention. In this embodiment, the inner surface of the metal tube 1 is coated with a glass-based fixing agent and has a diameter of 0.5 to 3 mm as a wear-resistant material.
This method employs a means for applying the powder mixture material 12 to the extent that the metal tube 1 is lowered while rotating the metal tube 1. This is different from the above-described embodiments in this point. , Metal tube 1, powder-grain mixed material 1
2, the high-frequency oscillator condition of the coil 3, the wear-resistant layer 4
Is the same as that of the example in the first embodiment, and the same means are denoted by the same reference numerals.

In the fourth embodiment, the metal tube 1
Is adopted because the wear-resistant material applied to the inner surface of the metal tube 1 is a powder-granular mixed material 12 of powder and granular material.
This is because compared to the powder material 2 described above, depending on its component, its fluidity is large and it may flow downward during melting, and the molten metal may flow down due to centrifugal force accompanying rotation of the metal tube 1. It is a measure of prevention.

(Examples) In the examples corresponding to the fourth embodiment, the following points are different from the examples in the above-described respective embodiments, and the other points are the same. . Rotational speed of metal tube; 100-350 times / minute Powder-mixed material; Iron-based powder (-250 to +60 microns) 30%
+ 70% of tungsten carbide (0.5-3mm)

FIG. 5 shows a fifth embodiment of the present invention. In this embodiment, the metal tube 1 is rotated but not moved downward, instead of moving downward. Only in the point that the means for moving the coil 3 disposed around the metal tube 1 at the same speed as the descending speed of the metal tube 1 in the first, third and fourth embodiments is adopted, Since this is different from the fourth embodiment, the same reference numerals are given to the same means, and the example in the fifth embodiment is also the same as that in the fourth embodiment. Same as the example.

FIG. 6 shows a sixth embodiment of the present invention. The difference from the fourth and fifth embodiments is that the metal tube 1 is moved down while rotating,
Since only the means for moving the coil 3 upward at the same speed as the descending speed of the metal tube 1 is employed, the same means are denoted by the same reference numerals, and the example of the sixth embodiment is also described. This embodiment is the same as the embodiment of the fourth embodiment, but in this embodiment, since the means for simultaneously moving both the metal tube 1 and the coil 3 in opposite directions is employed, the processing time is reduced to about half. it can.

FIG. 7 shows a seventh embodiment of the present invention. In this embodiment, the inner surface of the metal tube 1 is formed as a wear-resistant material not containing a binder and having a diameter of 1 to 9 mm. When applying the powder mixture material 12 of the degree powder body and the granular body to form the wear-resistant layer 4 by welding, as in the fourth embodiment, the applied powder and grain mixture is rotated by the centrifugal force of the metal tube 1. Material 12
After applying the powder-mixed material 12 to the inner surface of the metal tube 1 without employing a means for preventing the falling of the powder, the core tube 5 coated with the release material on the outer surface is inserted into the metal tube 1. In the same manner as in the first embodiment, a coil 3 connected to an AC power supply is arranged at a predetermined position around the metal tube 1 to energize the coil 3 and to connect the metal tube 1 to the axis line. The metal tube 1 is induction-heated by moving the metal tube 1 downward, and the thermal energy of the metal tube 1 melts the applied powder-mixed material 12 and fuses the material onto the inner surface of the metal tube 1. When the power supply to the coil 3 is stopped and the welding metal is stopped, the deposited metal solidifies and a wear-resistant layer 4 is formed on the inner surface of the metal tube 1.

According to the seventh embodiment, the presence of the core tube 5 inserted into the metal tube 1 allows the metal tube 1 to be processed during the processing without applying a rotational centrifugal force to the metal tube 1. It is possible to effectively prevent the powder-particle mixture material applied to the inner surface of the core tube 5 from flowing and falling, and since the release material is applied to the outer surface of the core tube 5, there is an advantage that the material can be used repeatedly and repeatedly. .

Next, an example corresponding to the seventh embodiment will be described. For example, a wear-resistant layer 4 is provided on the inner surface of a metal pipe 1 for transferring and pumping various materials in the steel and cement industries. In the case where welding is performed by using the powder-mixture material 12 as a wear material, an embodiment in which a high-frequency power supply having a frequency of 400 KHZ and 30 KW is connected to the surrounding coil 3 as shown in FIG. . Metal tube; STPG-90A, schedule 80, outer diameter φ101.6mm, wall thickness 8.1mm, length 600mm, descent speed 30mm / min Powder and mixed material; powder material; Co (cobalt) heat-resistant high alloy (Stellite No. 6) (Grain size 80-300 mesh) Granular material; Tungsten carbide 20% (0.5-2) Coating thickness; 4mm Core tube; Outer diameter φ75mm, wall thickness 5mm High frequency oscillator condition; Coil load voltage: 360V, Coil load current 170A Under the above conditions, a wear-resistant metal tube for transfer and pressure feeding was obtained, which was uniformly provided on the inner surface with a wear-resistant layer 4 having a welded layer thickness of 4 mm. Performance of wear-resistant metal pipes for transfer and pumping; When used for coal ash transport pipes, abrasion resistance and service life more than 5 times that of conventional high chromium cast iron pipes were obtained, and maintenance was unnecessary for 3 years. .

FIG. 8 shows an eighth embodiment of the present invention. The difference from the seventh embodiment is that the metal tube 1 is not moved and the coil 3 is moved to the seventh embodiment. This embodiment is similar to the seventh embodiment except that the metal tube 1 is moved upward in the direction of the arrow at the same speed as the moving speed of the metal tube 1, and other conditions are the same as those of the seventh embodiment. The performance of the metal tube is the same as that of the seventh embodiment. Therefore, the same means are denoted by the same reference numerals.

FIG. 9 shows a ninth embodiment of the present invention. The difference from the seventh and eighth embodiments is that both the metal tube 1 and the coil 3 are simultaneously moved in the opposite directions. Is moved at the same speed to
The metal tube 1 is moved downward in the direction of the arrow and the coil 3 is moved.
Is moved upward in the direction of the arrow, and is therefore different from the example of the first embodiment only in the following point. Therefore, the same means are denoted by the same reference numerals.

(Embodiment) In the embodiment corresponding to the ninth embodiment, the metal tube 1, the powder-mixture material 12, the coating thickness of the powder-mixture material, the high-frequency oscillator condition of the coil 3, the wear-resistant layer Since the thickness of the welded layer 4 and the like are the same as those in the example of the seventh embodiment, the same reference numerals are given to the same means, but in this embodiment, both the metal tube 1 and the coil 3 are used. Are simultaneously moved in opposite directions, so that the processing time can be reduced to about half.

FIG. 10 shows a tenth embodiment of the present invention, in which a metal tube 1 exposed to a corrosive environment or a high heating environment is used.
Is vertically arranged at the construction site so as to be able to move up and down, and a powder material 22 of a corrosion-resistant and heat-resistant material mixed with a glass-based adhesive is applied to the outer surface of the metal tube 1 to a predetermined thickness.
A coil 3 connected to an AC power supply in a predetermined position around
To energize the coil 3 and the metal tube 1
Is moved downward in the axial direction to cause induction heating of the metal tube 1, and the thermal energy of the metal tube 1 melts the coating powder material 22 and welds it to the outer surface of the metal tube 1. When the current supply to the coil 3 is stopped, the deposited metal solidifies and the corrosion-resistant and heat-resistant layer 14
Is formed. In addition, a small amount of a slag-making agent (slag component) may be added for smooth welding.

Next, an example corresponding to the tenth embodiment of the present invention will be described. (Embodiment) For example, the outer surface of a metal tube 1 such as a boiler tube used in a chemical plant, a power generation facility, etc.
When the heat-resistant layer 14 was formed by welding using a powder material 22 of corrosion-resistant and heat-resistant material, a current was passed through a surrounding-type coil 3 as shown in FIG. 10 by connecting a high-frequency power source having a frequency of 400 KHZ and 30 KW. Examples are shown below. Metal tube; STB-340 Outer diameter 42.7mm, wall thickness 3mm, length 15
00mm, descending speed 50mm / min Powder material; Ni-Cr-B-Si-WC- alloy powder Coating thickness; 2mm High frequency oscillator condition; Coil load voltage: 360V, Coil load current 170A, Coil inner diameter φ70mm Welding under the above conditions Corrosion-resistant, heat-resistant layer 14 with a thickness of 1.5 mm
Was uniformly provided on the outer surface, and a corrosion-resistant and heat-resistant metal tube was obtained. The performance of the metal tube: corrosion of the outer surface of the pipe, corrosion due to high-temperature SOx and the like, and abrasion due to flying high-temperature dust were significantly reduced.

FIG. 11 shows an eleventh embodiment of the present invention. The difference from the tenth embodiment is that the metal tube 1 is not moved and the coil 3 is moved to the tenth embodiment.
This is a point that the metal tube 1 is moved upward in the direction of the arrow at the same speed as the moving speed of the metal tube 1 in the embodiment, and the other execution conditions are the same as those in the tenth embodiment. The performance of the metal tube is the same as that of the tenth embodiment. Therefore, the same means are denoted by the same reference numerals.

FIG. 12 shows a twelfth embodiment of the present invention. The difference from the tenth and eleventh embodiments is that both the metal tube 1 and the coil 3 are simultaneously moved in the opposite directions. This embodiment is different from the first embodiment in that the metal tube 1 is moved downward in the direction of the arrow and the coil 3 is moved upward in the direction of the arrow.
Therefore, it differs from the example of the tenth embodiment only in the following points. Therefore, the same means are denoted by the same reference numerals.

(Examples) In an example corresponding to the twelfth embodiment, the metal tube 1, the powder material 22, the coating thickness of the powder material, the high-frequency oscillator condition of the coil 3, the corrosion resistance,
Since the thickness of the heat-resistant layer 14 and the like are the same as those in the example of the tenth embodiment, the same reference numerals are given to the same means.
Are simultaneously moved in opposite directions, so that the processing time can be reduced to about half.

FIG. 13 shows a thirteenth embodiment of the present invention, in which a metal tube 1 exposed to a corrosive environment or a high heating environment is used.
Is vertically arranged at the construction site so as to be able to move up and down, and the outer surface of the metal tube 1 is coated with a powder-mixed material 32 of a powder having a diameter of about 0.5 to 3 mm as a corrosion-resistant and heat-resistant material mixed with an adhesive. When forming the heat-resistant layer 14 by welding, the applied powder-mixture material 32 has a large fluidity, so that it is prevented from flowing down during melting and a smooth coating layer is formed. A short tubular mold 6 around the metal tube 1
Is mounted so as to be able to move up and down, and a coil 3 connected to an AC power supply is arranged outside the mold 6 to energize the coil 3 while moving the metal tube 1 downward in the axial direction.
By rotating the metal tube 1 about its axis, the metal tube 1 is induction heated, and the thermal energy of the metal tube 1 melts the coating powder / particle mixed material 32 and welds it to the outer surface of the metal tube 1. When the lowering and rotation of the metal tube 1 and the energization of the coil 3 are stopped after that, the deposited metal solidifies and a corrosion-resistant and heat-resistant layer 14 is formed on the outer surface of the metal tube 1.

Next, an example corresponding to the thirteenth embodiment of the present invention will be described. (Embodiment) For example, the outer surface of a metal tube 1 such as a boiler tube used in a chemical plant, a power generation facility, etc.
In the case where the heat-resistant layer 14 is formed by welding using a powder-particle mixed material 32 obtained by mixing a powder and a granular material as a corrosion-resistant and heat-resistant material, the surrounding coil 3 as shown in FIG. An embodiment in which the high-frequency power supply is connected to carry out the energization processing is described below. Metal tube; STB-340, outer diameter φ42.7mm, wall thickness 3mm, length 1
000mm, descending speed 30mm / min Powder mixed material; Co-Cr-W powder (80-280 mesh)
+ 10% WC (0.5-1mm) Coating thickness; 4mm-5mm Die; Alumina ceramics High frequency oscillator condition; Coil load voltage 360V, Coil load current 170A, Coil inner diameter φ90mm Corrosion resistance and heat resistance of 2mm welding layer thickness under the above conditions A corrosion-resistant, heat-resistant metal tube having the layer 14 uniformly on the outer surface was obtained. Performance of the metal tube The coated metal tube is particularly effective in preventing heat cracks and cracks due to thermal shock, and can be used as a means for preventing cooling water from leaking from the boiler tube.

FIG. 14 shows a fourteenth embodiment of the present invention. The difference from the thirteenth embodiment is that the metal tube 1 is rotated but not moved downward.
Only the point at which the mold 6 and the coil 3 were moved upward in the direction of the arrow at the same speed as the descending speed of the metal tube 1 in the thirteenth embodiment, other conditions were the same as in the thirteenth embodiment. The performance is the same as that of the thirteenth embodiment and the performance of the metal tube after the treatment is the same as that of the thirteenth embodiment. Therefore, the same means are denoted by the same reference numerals.

FIG. 15 shows a fifteenth embodiment of the present invention. The difference from the thirteenth and fourteenth embodiments is that the metal tube 1 is This is a point that both the mold 6 and the coil 3 are simultaneously moved in the opposite direction at the same speed. In this embodiment, the metal tube 1 is moved downward in the direction of the arrow while rotating, and the mold 6 is moved.
And that the coil 3 is moved upward in the direction of the arrow, and thus differs from the example of the thirteenth embodiment only in the following points. Therefore, the same means are denoted by the same reference numerals.

EXAMPLE An example corresponding to the fifteenth embodiment is described with reference to a metal tube 1, a powder / grain mixed material 32,
Coating thickness of the powder / particle mixture material, high-frequency oscillator condition of the coil 3,
Since the mold 6, the corrosion resistance, the thickness of the welded layer of the heat layer 14, and the like are the same as those of the example in the thirteenth embodiment, the same means are denoted by the same reference numerals. Since the means for simultaneously moving both the metal tube 1, the mold 6, and the coil 3 in opposite directions is employed, the processing time can be reduced to about half.

FIG. 16 shows a sixteenth embodiment of the present invention. In this embodiment, a gap between the inner surface of the mold 6 and the corrosion-resistant and heat-resistant layer 14 made of the powder-mixture material 32 is used. to, from the top of the mold 6, for example, MgO-SiO ₂ -CoF ₂
The present embodiment differs from the thirteenth embodiment only in that a means for continuously or discontinuously adding the -MnO-based flux 7 is adopted, and the other points are completely the same.
Therefore, the same means are denoted by the same reference numerals. According to the embodiment, since the slag layer 8 after melting and solidification can be formed uniformly along the surface of the corrosion-resistant and heat-resistant layer 14 made of the powder-particle mixture material 32, a uniform and smooth surface treatment layer can be obtained. can get.

FIGS. 17 and 18 show the seventeenth and eighteenth embodiments of the present invention, respectively. In the fourteenth and fifteenth embodiments, the flux is similar to that of the sixteenth embodiment. The first point only in the point that the means for adding
This is different from the fourth and fifteenth embodiments, and the other points are completely the same. Therefore, the same symbols are given to the same means.

In each of the above embodiments and examples, the thickness of the durable metal layer (abrasion and corrosion resistant layer) formed on the inner and outer surfaces of the metal tube is preferably in the range of 0.1 to 5 mm.
The reason is based on the following. If the layer thickness is less than 0.1mm, conventional techniques such as brazing and thermal spraying can be used,
Since it is economically and efficiently the same as the present invention, it is meaningless, and it is practically difficult to apply and control the granular metal material with a layer thickness smaller than 0.1 mm. Also, the layer thickness is 5mm
If it is thicker, large induction heating energy is required to uniformly dissolve and weld the powder metal material, and there is a danger that the metal tube itself will be overheated due to increased heating, resulting in deterioration of the material.

The main embodiments and examples of the present invention have been described above. However, the present invention is not limited to these, and the scope of the present invention can be achieved without departing from the gist of the invention. Various design changes are possible within the scope of the present invention, all of which are to be included in the present invention.

[0044]

According to the present invention, since the durable metal layer is formed on the inner and outer surfaces of the metal pipe according to the above-mentioned processing method, the following excellent effects are obtained.

(1) When forming a durable metal layer such as a wear-resistant layer or a corrosion-resistant layer on the inner and outer surfaces of a metal tube exposed to a severe wear environment or a corrosive environment, a desired build-up layer thickness is required. And a durable metal layer of a predetermined component which has been formed by metallurgical bonding with an extremely small dilution ratio can be easily and reliably formed.

(2) The metal tube is arranged vertically, and the metal tube and / or the coil disposed around the metal tube is vertically moved, and / or the surface treatment is performed while rotating the metal tube. Since the means is adopted, it is advantageous in terms of space as compared with the above-described conventional technology in which the metal tube is arranged sideways to perform the surface treatment, and can be applied to the surface treatment of a significantly long metal tube, The efficiency and accuracy of the surface treatment can be significantly improved.

(3) The lower limit of the inner diameter of the metal tube is not remarkably limited as in the prior art described above, and the present invention can be easily and reliably applied to the inner surface treatment of a metal tube having a remarkably small diameter.

[Brief description of the drawings]

FIG. 1 is a simplified explanatory diagram of a first embodiment of the present invention.

FIG. 2 is a simplified explanatory diagram of a second embodiment of the present invention.

FIG. 3 is a simplified explanatory diagram of a third embodiment of the present invention.

FIG. 4 is a simplified explanatory diagram of a fourth embodiment of the present invention.

FIG. 5 is a simplified explanatory diagram of a fifth embodiment of the present invention.

FIG. 6 is a simplified explanatory diagram of a sixth embodiment of the present invention.

FIG. 7 is a simplified explanatory diagram of a seventh embodiment of the present invention.

FIG. 8 is a simplified explanatory diagram of an eighth embodiment of the present invention.

FIG. 9 is a simplified explanatory diagram of a ninth embodiment of the present invention.

FIG. 10 is a simplified explanatory diagram of a tenth embodiment of the present invention.

FIG. 11 is a simplified explanatory diagram of an eleventh embodiment of the present invention.

FIG. 12 is a simplified explanatory diagram of a twelfth embodiment of the present invention.

FIG. 13 is a simplified explanatory diagram of a thirteenth embodiment of the present invention.

FIG. 14 is a simplified explanatory diagram of a fourteenth embodiment of the present invention.

FIG. 15 is a simplified explanatory diagram of a fifteenth embodiment of the present invention.

FIG. 16 is a simplified explanatory diagram of a sixteenth embodiment of the present invention.

FIG. 17 is a simplified explanatory diagram of a seventeenth embodiment of the present invention.

FIG. 18 is a schematic explanatory view of an eighteenth embodiment of the present invention.

FIG. 19 is a simplified explanatory view showing one example of a conventional method for hardfacing the inner surface of a metal tube.

FIG. 20 is a simplified explanatory view showing one example of a conventional method for hardfacing the outer surface of a metal tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal tube 2 Powder material 3 Coil 4 Wear layer 5 Core tube 6 Die 7 Flux 8 Slag layer 12 Powder mixed material 14 Corrosion-resistant and heat-resistant layer 22 Powder material 32 Powder mixed material

Claims (18)

[Claims] When forming a durable metal layer made of metallurgical bonding on the inner surface of a metal tube, the metal tube is arranged vertically.
A powdery and durable metal material mixed with a binder is applied to the inner surface of the metal tube, and a coil connected to an AC power supply is arranged around the metal tube to energize the coil. By moving one of them in the axial direction of the metal tube, the metal tube or the powdery and durable metal material is heated by induction heating to melt the powdery and durable metal material. A surface treatment method for a metal tube, comprising forming a durable metal layer by welding to an inner surface of a heated metal tube. 2. The method according to claim 1, wherein both the metal tube and the coil are moved in opposite directions. 3. The surface treatment method for a metal tube according to claim 1, wherein the metal tube is rotated. 4. The metal according to claim 1, wherein a wear-resistant layer is formed on an inner surface of the metal pipe by using a wear-resistant material as a powdery and durable metal material. Tube surface treatment method. 5. The metal according to claim 1, wherein a corrosion-resistant layer is formed on the inner surface of the metal tube by using a corrosion-resistant material as a powdery and durable metal material. Tube surface treatment method. 6. When forming a durable metal layer made of metallurgical bonding on the inner surface of a metal tube, the metal tube is arranged vertically.
After applying a powdery and durable metal material mixed with a binder to the inner surface thereof, insert a core tube coated with a release material on the outer surface into the metal tube, and connect an AC power source around the metal tube. Surrounding the coil and energizing the coil, and moving at least one of the metal tube and the coil in the axial direction of the metal tube to heat the metal tube or the powdery and durable metal material by induction heating. Melting the powdery and durable metal material and welding the melted durable metal material to the inner surface of the heated metal tube to form a durable metal layer. . 7. The surface treatment method for a metal tube according to claim 6, wherein both the metal tube and the coil are moved in opposite directions. 8. The surface treatment method for a metal tube according to claim 6, wherein a wear-resistant layer is formed on an inner surface of the metal tube by using a wear-resistant material as a powdery and durable metal material. . 9. The method for treating a surface of a metal tube according to claim 6, wherein a corrosion-resistant layer is formed on an inner surface of the metal tube by using a corrosion-resistant material as a powdery and durable metal material. . 10. When forming a durable metal layer formed by metallurgical bonding on the outer surface of a metal tube, the metal tube is disposed vertically, and a powdery durable metal material mixed with a binder is provided on the outer surface. By applying and encircling a coil connected to an AC power supply around the metal tube and energizing the coil, and moving at least one of the metal tube and the coil in the axial direction of the metal tube. To heat the powdered and durable metal material by induction heating to melt the powdered and durable metal material, and weld the melted durable metal material to the outer surface of the heated metal tube to form a durable metal layer. Forming a surface of a metal tube. 11. The method of claim 10, wherein both the metal tube and the coil are moved in opposite directions. 12. The surface treatment method for a metal pipe according to claim 10, wherein a wear-resistant layer is formed on an outer surface of the metal pipe by using a wear-resistant material as a powdery and durable metal material. . 13. The method according to claim 10, wherein a corrosion-resistant layer is formed on an outer surface of the metal tube by using a corrosion-resistant material as a powdery and durable metal material. . 14. When forming a durable metal layer formed by metallurgical bonding on the outer surface of a metal tube, the metal tube is disposed vertically, and a powdery durable metal material mixed with a binder is provided on the outer surface. And a short-tube mold for preventing the coating material from flowing down and forming a smooth coating layer is fitted around the metal tube, and an AC power supply is provided outside the mold. And energizing the coil, and moving at least one of the metal tube and the mold surrounding the coil in the axial direction of the metal tube, and moving the metal tube along its axis. , The metal tube or the powdery and durable metal material is heated by induction heating to melt the powder and durable metal material, and the molten durable metal material is heated by the heated metal tube. To form a durable metal layer by welding to the outer surface of Metal tube surface treatment method. 15. A metal pipe and at least one axis of a mold surrounding a coil while appropriately adding a flux from above the mold to a gap between a coating layer of a durable metal material and an inner surface of the mold. Moving in the direction and rotating the metal tube.
5. The surface treatment method for a metal tube according to 4. 16. The surface treatment method for a metal tube according to claim 14, wherein both the metal tube and the mold surrounding the coil are moved in opposite directions. 17. The metal according to claim 14, wherein a wear-resistant layer is formed on an outer surface of the metal pipe by using a wear-resistant material as a powdery and durable metal material. Tube surface treatment method. 18. The metal according to claim 14, wherein a corrosion-resistant layer is formed on the outer surface of the metal tube by using a corrosion-resistant material as a powdery and durable metal material. Tube surface treatment method.