阅读说明：本技术 小径管焊接头焊后热处理无冷却感应加热器及其制作方法 (Cooling-free induction heater for postweld heat treatment of small-diameter pipe welding joint and manufacturing method thereof ) 是由 汪洋 连丽 豆志远 王顺阳 邢增为 王顺兴 丁光柱 孙松涛 陈东旭 周旭东 李世 于 2019-10-12 设计创作，主要内容包括：本发明公开了一种小径管焊接头焊后热处理无冷却感应加热器及其制作方法,在小径管外壁焊缝处设置有小径管导电感应器,小径管导电感应器为片状蛇形贴面结构,分左侧片状小径管导电感应器和右侧片状小径管导电感应器,两侧的片状小径管导电感应器结构一致,均呈扇环形结构,扇环形的内环半径R等于小径管的半径r加上小径管的管壁厚度s,即：R=r+s,所述左侧片状小径管导电感应器和右侧片状小径管导电感应器的扇环长度X<Sub>1(The invention discloses a small-diameter pipe welding joint postweld heat treatment cooling-free induction heater and a manufacturing method thereof, wherein a small-diameter pipe conductive inductor is arranged at a welding seam of the outer wall of a small-diameter pipe, the small-diameter pipe conductive inductor is of a sheet snake-shaped veneering structure, the left sheet small-diameter pipe conductive inductor and the right sheet small-diameter pipe conductive inductor are separated, the sheet small-diameter pipe conductive inductors at two sides are consistent in structure and are of a fan-ring structure, and the radius R of the fan-ring inner ring is equal to the radius R of the small-diameter pipe plus the pipe wall thickness s of the small-diameter pipe, namely: r = R + s, and the fan ring length X of the left and right sheet small-diameter tube conductive inductors 1 and the left sheet small-diameter tube conductive inductor and the right sheet small-diameter tube conductive inductor are pasted on the outer wall of the small-diameter tube in a semi-surrounding shape. The invention solves the problem of heat treatment of the small-diameter pipe joint which is difficult to treat by the traditional copper pipe, reduces the traditional water cooling circulation system,thereby saving costs.)

1. The utility model provides a no cooling induction heater of path pipe soldered connection postweld thermal treatment, includes path pipe (3), its characterized in that: the utility model discloses a small diameter pipe (3) outer wall welding seam department is provided with small diameter pipe conductive inductor, small diameter pipe conductive inductor is slice snakelike wainscot structure, divides left side slice small diameter pipe conductive inductor (1) and right side slice small diameter pipe conductive inductor (2), left side slice small diameter pipe conductive inductor (1) and right side slice small diameter pipe conductive inductor (2) structure are unanimous, all are fan ring shape structure, and fan annular inner ring radius R equals the radius R of small diameter pipe plus the tube wall thickness s of small diameter pipe, promptly: r = R + s, and the fan-ring length X of the left sheet small-diameter tube conductive inductor (1) and the right sheet small-diameter tube conductive inductor (2)₁= π R-s; the left sheet small-diameter tube conductive inductor (1) and the right sheet small-diameter tube conductive inductor (2) are pasted on the outer wall of the small-diameter tube (3) in a semi-surrounding shape; u-shaped winding turns of winding belt of sheet-shaped snake-shaped veneering structure and straight small-diameter pipe (3)the diameters are matched, and the number of U-shaped winding turns is increased by one turn when the diameter of the small-diameter pipe (3) is increased by 20 mm; the gap distance L between the left sheet small-diameter tube conductive inductor (1) and the right sheet small-diameter tube conductive inductor (2)₁Equal to the wall thickness s of the small-diameter pipe (3) and the width n of the winding belt of the sheet-shaped snake-shaped veneering structure₁is 1 to 1.3 times of the wall thickness of the small-diameter pipe (3), and the gap distance m between adjacent winding belts₁is 0.6 to 0.8 times of the wall thickness of the small-diameter pipe (3); the left sheet small-diameter tube conductive inductor (1) and the right sheet small-diameter tube conductive inductor (2) comprise an inductor insulating layer (31), an inductor conductive layer (32) and an inductor heat-insulating layer (33) from inside to outside, and the inductor insulating layer (31) is adhered to the outer wall of the small-diameter tube (3).

2. the small-diameter tube welding joint post-weld heat treatment cooling-free induction heater according to claim 1, characterized in that: the inductor conducting layer (32) is formed by cutting a copper plate, and Ni-P alloy is chemically plated on the surface of the inductor conducting layer (32) to prevent the inductor conducting layer (32) from being oxidized at high temperature; the inductor insulating layer (31) is positioned between the small-diameter pipe (3) and the inductor conducting layer (32) and has double effects of insulation and heat preservation; the inductor heat-insulating layer (33) is positioned on the outer side of the inductor conducting layer (32) and has double effects of insulation and heat preservation.

3. The method for manufacturing the small-diameter pipe welding joint post-weld heat treatment cooling-free induction heater as claimed in claim 1 or 2, comprises the following specific steps:

Cutting and forming a copper plate with the thickness of 0.3-0.5 mm according to the shapes of a left sheet small-diameter tube conductive inductor (1) and a right sheet small-diameter tube conductive inductor (2), and bending the copper plate into a sheet snake-shaped veneering structure to obtain an inductor conductive layer (32);

Chemically plating a layer of Ni-P alloy on the surface of the inductor conducting layer (32) to prevent the inductor conducting layer from being oxidized at high temperature, wherein the thickness of the Ni-P alloy plating layer is 1/12-1/15 of the thickness of the inductor conducting layer (32);

a sensor insulating layer (31) is arranged between the sensor conducting layer (32) and the small-diameter pipe (3), the sensor insulating layer (31) is formed by bonding glass ribbons layer by layer through a high-temperature bonding agent, the high-temperature bonding agent is formed by mixing aluminum oxide and aluminum dihydrogen phosphate, the molar ratio of the aluminum oxide to the aluminum dihydrogen phosphate is 1:2, and the thickness of the sensor insulating layer (31) is 1/6-1/8 of the thickness of the pipe wall of the large-diameter pipe (3);

An inductor heat-insulating layer (33) is arranged outside the inductor conducting layer (32) and the Ni-P alloy coating, the inductor heat-insulating layer (33) is formed by bonding glass ribbons layer by layer through a high-temperature adhesive, the high-temperature adhesive is formed by mixing alumina and aluminum dihydrogen phosphate, the molar ratio of the alumina to the aluminum dihydrogen phosphate is 1:2, and the thickness of the inductor heat-insulating layer (33) is 1/5-1/6 of the thickness of the small-diameter pipe (3);

the thickness of the inductor insulating layer (33) is more than or equal to that of the inductor insulating layer (31);

when the left sheet small-diameter tube conductive inductor (1) and the right sheet small-diameter tube conductive inductor (2) are manufactured, an inductor insulating layer (31), an inductor conductive layer (32) and an inductor insulating layer (33) are sequentially bonded on dies of the left sheet small-diameter tube conductive inductor (1) and the right sheet small-diameter tube conductive inductor (2) respectively, and then naturally dried for 0.5-1.0 hour after bonding, and then heated and dried at the temperature of 60-80 ℃;

seventhly, after the left sheet-shaped small-diameter tube conductive inductor (1) and the right sheet-shaped small-diameter tube conductive inductor (2) are manufactured and subjected to recrystallization annealing, bending and forming, wherein the radius R of the bending radian of the left sheet-shaped small-diameter tube conductive inductor (1) and the right sheet-shaped small-diameter tube conductive inductor (2) is the radius R of the small-diameter tube (3) plus the tube wall thickness s of the small-diameter tube (3), namely: r = R + s, and the fan-ring length X of the left sheet small-diameter tube conductive inductor (1) and the right sheet small-diameter tube conductive inductor (2)₁ =πR-s ；

Subjecting the bent and formed left sheet-shaped small-diameter tube conductive inductor (1) and the right sheet-shaped small-diameter tube conductive inductor (2) to stress relief annealing and chemical nickel-phosphorus alloy plating to obtain the formed left sheet-shaped small-diameter tube conductive inductor (1) and the right sheet-shaped small-diameter tube conductive inductor (2);

When the small-diameter pipe inductor (1) and the small-diameter pipe inductor (2) are semi-surrounded and stuck to the outer wall of the small-diameter pipe (3).

Technical Field

The invention relates to the technical field of heat treatment, in particular to a small-diameter pipe welding joint post-weld heat treatment cooling-free induction heater and a manufacturing method thereof, which are suitable for post-weld heat treatment heating of a heated surface pipe in a boiler of a thermal power plant.

background

The traditional postweld heat treatment of the welded joint of the heating surface pipe in the boiler of the thermal power plant adopts flame heating or far infrared heating. Flame heating is difficult to ensure uniform temperature due to low efficiency and great influence of operation skills, and is only used for postweld heat treatment of individual repair welding joints of medium and low alloy steel. The flexible resistance heating is suitable for preheating before welding, postheating and postwelding heat treatment, adopts a thermocouple to measure the temperature, and uses automatic temperature control equipment to monitor and record the temperature. However, when the flexible resistance heating is adopted, the requirement on the surface quality of the processed welding joint is high, and a special clamp is required to be manufactured for tightly adhering the heater and the weldment, so that the operation is troublesome and a large space is required. When the far infrared heating is carried out, each welding opening heating device, each thermocouple and each heat preservation device are installed one by one, the efficiency is low, and the temperature field is influenced by a plurality of factors; when the number of the welded junctions is small and the wall thickness of the part is not large, the heat treatment method can meet the requirement of engineering progress and can also ensure the temperature gradient of the joint area of the part. However, with the rapid increase of the number of joints needing postweld heat treatment, the increase of time required for postweld heat treatment and the deterioration of a temperature field caused by the increase of the wall thickness of a material, the traditional heating method and process are far from meeting the requirements of engineering progress and engineering quality. Quality accidents (such as rework, cutting off a welding joint and re-welding) caused by the traditional postweld heat treatment process appear greatly in recent years, wherein the welding joint of the small-diameter tube with the largest number and the most prominent problem is the welding joint of the small-diameter tube with the heating surface.

the medium frequency induction heating utilizes the principle that the conversion among electricity, magnetism and heat energy is utilized to heat the heated object, and can be used for carrying out postweld heat treatment on a welded joint. The current inductors are mainly classified into two types, one type is wound by a copper pipe and cooled by water, the other type is wound by a copper cable, and a heat insulation layer is arranged between the copper cable and a heated workpiece. Medium frequency induction heating has been applied to heat treatment of small-diameter pipe materials, but because the space between the small-diameter pipes of the heating surface is small and only about 5mm exists, the existing inductor cannot be installed, so that the medium frequency induction heating is not applied to post-welding heat treatment of the small-diameter pipe joints of the heating surface.

disclosure of Invention

the technical problem to be solved by the invention is as follows: the inductor is suitable for plane heating, arc surface or other heating occasions which can be unfolded into a plane, and solves the problem of heat treatment of the welded joint of the small-diameter tube which is difficult to treat by the traditional copper tube by designing the inductor into a sheet-shaped snake-shaped veneered structure.

the technical scheme adopted by the invention for solving the technical problem is as follows:

The utility model provides a no cooling induction heater of path pipe soldered connection postweld thermal treatment, includes the path pipe, path pipe outer wall welding seam department is provided with path pipe electric inductor, path pipe electric inductor is slice snakelike wainscot structure, divides left side slice path pipe electric inductor and right side slice path pipe electric inductor, left side slice path pipe electric inductor and right side slice path pipe electric inductor structure are unanimous, all are fan annular structure, fan annular inner ring radius R equals radius R of path pipe plus the tube wall thickness s of path pipe, promptly: r = R + s, and the fan ring length X of the left and right sheet small-diameter tube conductive inductors₁= π R-s; the left sheet small-diameter tube conductive inductor and the right sheet small-diameter tube conductive inductor are pasted on the outer wall of the small-diameter tube in a semi-surrounding shape; the number of U-shaped winding turns of the winding belt of the sheet-shaped snake-shaped veneering structure is matched with the diameter of the small-diameter pipe, and the number of U-shaped winding turns is increased by one turn when the diameter of the small-diameter pipe is increased by 20 mm; the gap distance L between the left sheet small-diameter tube conductive inductor and the right sheet small-diameter tube conductive inductor₁equal to the wall thickness s of the small-diameter pipe and the width n of the winding belt of the sheet-shaped snake-shaped veneering structure₁Is 1-1.3 times of the wall thickness of the small-diameter pipe, and the gap distance m between adjacent winding belts₁Of small diameter tube wall thickness (0.6)About 0.8) times; the left sheet small-diameter tube conductive inductor and the right sheet small-diameter tube conductive inductor respectively comprise an inductor insulating layer, an inductor conductive layer and an inductor insulating layer from inside to outside, and the inductor insulating layers are adhered to the outer wall of the small-diameter tube.

The inductor conducting layer is formed by cutting a copper plate, and Ni-P alloy is chemically plated on the surface of the inductor conducting layer to prevent the inductor conducting layer from being oxidized at high temperature; the inductor insulating layer is positioned between the small-diameter pipe and the inductor conducting layer, and has double effects of insulation and heat preservation; the inductor heat-insulating layer is positioned on the outer side of the inductor conducting layer, and has double effects of insulation and heat preservation.

the manufacturing method of the small-diameter pipe welding joint post-welding heat treatment cooling-free induction heater comprises the following specific steps:

cutting and forming a copper plate with the thickness of 0.3-0.5 mm according to the shapes of a left sheet-shaped small-diameter tube conductive inductor and a right sheet-shaped small-diameter tube conductive inductor, and bending the copper plate into a sheet-shaped snake-shaped veneering structure to obtain a sensor conductive layer;

Chemically plating a Ni-P alloy plating layer on the surface of the conductive layer of the inductor to prevent the conductive layer of the inductor from being oxidized at high temperature, wherein the thickness of the Ni-P alloy plating layer is 1/12-1/15 of the thickness of the conductive layer of the inductor;

A sensor insulating layer is arranged between the sensor conducting layer and the small-diameter pipe, the sensor insulating layer is formed by bonding glass ribbons layer by layer through a high-temperature binder, the high-temperature binder is formed by mixing aluminum oxide and aluminum dihydrogen phosphate, the molar ratio of the aluminum oxide to the aluminum dihydrogen phosphate is 1:2, and the thickness of the sensor insulating layer is 1/6-1/8 of the thickness of the large-diameter pipe;

Fourthly, arranging an inductor heat-insulating layer outside the inductor conducting layer and the Ni-P alloy coating, wherein the inductor heat-insulating layer is formed by bonding glass ribbons layer by layer through a high-temperature binder, the high-temperature binder is formed by mixing alumina and aluminum dihydrogen phosphate, the molar ratio of the alumina to the aluminum dihydrogen phosphate is 1:2, and the thickness of the inductor heat-insulating layer is 1/5-1/6 of the thickness of the small-diameter pipe wall;

The thickness of the inductor insulating layer is more than or equal to that of the inductor insulating layer;

When manufacturing the left sheet small-diameter tube conductive inductor and the right sheet small-diameter tube conductive inductor, sequentially bonding an inductor insulating layer, a large inductor conductive layer and an inductor insulating layer on the dies of the left sheet small-diameter tube conductive inductor and the right sheet small-diameter tube conductive inductor respectively, naturally airing for 0.5-1.0 hour after bonding, and then heating and drying at the temperature of 60-80 ℃;

Seventhly, after the left sheet-shaped small-diameter tube electric guide inductor and the right sheet-shaped small-diameter tube electric guide inductor are manufactured and subjected to recrystallization annealing, bending and forming, wherein the radius R of the bending radians of the left sheet-shaped small-diameter tube electric guide inductor and the right sheet-shaped small-diameter tube electric guide inductor is the sum of the radius R of the small-diameter tube and the tube wall thickness s of the small-diameter tube, namely: r = R + s, and the fan ring length X of the left and right sheet small-diameter tube conductive inductors₁ =πR-s ；

subjecting the bent and formed left sheet-shaped small-diameter tube conductive inductor and the right sheet-shaped small-diameter tube conductive inductor to stress relief annealing and chemical nickel-phosphorus alloy plating processes to obtain the formed left sheet-shaped small-diameter tube conductive inductor and the right sheet-shaped small-diameter tube conductive inductor;

and ninthly, when the device is used, the left sheet small-diameter tube conductive inductor and the right sheet small-diameter tube conductive inductor are semi-surrounded and are adhered to the outer wall of the small-diameter tube.

the processed copper plate is subjected to recrystallization annealing, so that the work hardening effect is eliminated, the copper plate is convenient to bend and deform in the next step, the internal stress is eliminated, the size of the inductor is prevented from changing during working, and the size stability of the conductive inductor is improved.

The invention carries out stress relief annealing on the bent copper plate so as to eliminate the internal stress and reduce the tendency of deformation and cracking of the conductor in the conductive inductor during working.

The invention adopts the Cu sheet with certain thickness to manufacture the inductor, saves space, but can not adopt water cooling, so the method of chemical plating Ni-P is adopted to prevent the inductor from being oxidized during heating.

the invention has the following positive beneficial effects:

1. The space is saved:

adopt the copper sheet of slice veneer formula to do the inductor, reach inductor "miniaturization" purpose, through designing into two structures with the inductor, directly merge two inductors through mechanical method during the heating, can avoid the trouble that can meet when integral inductor installs.

2. Cooling in the absence of water:

The sheet inductor does not need to be cooled by water, so that the cost is saved by reducing the traditional water cooling circulation system.

3. High-temperature oxidation prevention of the chemical plating layer:

When pure copper is used as the inductor material, if the pure copper is not cooled, the temperature of the inductor is close to the heating temperature, and the oxidation is easy to occur, so that the Ni-P alloy plating layer chemically plated on the surface of the inductor can effectively prevent the oxidation.

4. heat insulation composite layer:

the invention uses the mixture of alumina and aluminum dihydrogen phosphate as the high-temperature adhesive on the surface of the inductor, and the glass ribbon is adhered on the surface of the inductor, thereby playing the dual functions of insulation and heat preservation, improving the integral strength of the inductor and prolonging the service life.

Drawings

FIG. 1 is a schematic structural diagram of a sheet-shaped serpentine veneering conductive inductor of a small-diameter pipe with a diameter of 45 mm;

FIG. 2 is a schematic structural diagram of a sheet-shaped serpentine veneering conductive inductor of a small-diameter pipe with a diameter of 70 mm;

FIG. 3 is a schematic diagram of the position structure of the small-diameter tube and the sheet-shaped serpentine veneering conductive sensor;

fig. 4 is a top view of fig. 3.

Detailed Description

the invention will be further explained and explained with reference to the following examples and drawings: