CN114029576A

CN114029576A - Method for welding opening of expansion valve

Info

Publication number: CN114029576A
Application number: CN202010933719.6A
Authority: CN
Inventors: 宋明
Original assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Current assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Priority date: 2020-09-08
Filing date: 2020-09-08
Publication date: 2022-02-11
Anticipated expiration: 2040-09-08
Also published as: CN114029576B

Abstract

The invention provides a welding method of an expansion valve pipe orifice, and belongs to the technical field of welding. The welding method of the expansion valve pipe orifice comprises an expansion valve, a pipe and a restrictor, wherein the pipe orifice of the expansion valve is provided with an expanding opening, the end part of the pipe is inserted at the expanding opening, a welding seam is formed between the expanding opening and the pipe, and the restrictor is positioned inside the connecting part of the expansion valve pipe orifice and the pipe; the welding method comprises the following steps: preheating: preheating a position 2-4 mm below a welding line at a flaring part, and then preheating the welding line and a region 10-15 mm above the welding line by adjusting flame upwards; adding brazing filler metal and preserving heat: adding brazing filler metal into the welding seam to enable the brazing filler metal to be melted, flow and joint filled; and repeatedly moving the flame back and forth to keep the temperature of the welding seam and the range of 10mm above and below the welding seam until the brazing filler metal penetrates to form a welding angle. The welding method of the expansion valve pipe orifice can firmly fix the throttle arranged in the pipe orifice, and avoids the occurrence of noise.

Description

Method for welding opening of expansion valve

Technical Field

The invention belongs to the technical field of welding, and particularly relates to a method for welding an expansion valve pipe orifice.

Background

The electronic expansion valve is an important functional part in an air conditioner, at present, the purposes of throttling and noise reduction are achieved by adding built-in throttlers at two ends of a pipe orifice of the electronic expansion valve, the pipe orifice of the electronic expansion valve and a pipe are only welded in the process of welding the pipe orifice of the expansion valve and the pipe, the throttlers are not firmly fixed, and the problems that a refrigerant drives the throttlers to move up and down in the heating operation, impact is carried out in the welding position, and metal friction causes noise are caused.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the invention provides a welding method of the orifice of the expansion valve, which can firmly fix the throttle arranged in the orifice and avoid the occurrence of noise.

According to the embodiment of the disclosure, the welding method of the expansion valve nozzle comprises the following steps: the expansion valve comprises an expansion valve, a pipe and a restrictor, wherein a pipe opening of the expansion valve is provided with a flared opening, the end part of the pipe is inserted into the flared opening, a welding seam is formed between the flared opening and the pipe, and the restrictor is positioned in the connection part of the pipe opening of the expansion valve and the pipe; the welding method comprises the following steps: preheating: preheating a position 2-4 mm below a welding line at a flaring part, and then preheating the welding line and a region 10-15 mm above the welding line by adjusting flame upwards; adding brazing filler metal and preserving heat: adding brazing filler metal into the welding seam to enable the brazing filler metal to be melted, flow and joint filled; and repeatedly moving the flame back and forth to keep the temperature of the welding seam and the range of 10mm above and below the welding seam until the brazing filler metal penetrates to form a welding angle.

According to the welding method disclosed by the invention, the welding seam and the area above the welding seam are preheated within the range of 2-4 mm below the welding seam at the flaring part, the outer wall of the throttle at the position of 2-4 mm below the flaring part is directly contacted with the inner wall of the pipe at the outer side of the welding seam, the temperature of the throttle inside the welding seam can be quickly raised by preheating the position, the speed of the whole preheating process is improved, the fact that the throttle is firmly welded when subsequent brazing filler metal can be melted and flows to the position is ensured, and the problem that the throttle is insecure and generates impact noise is avoided.

According to an embodiment of the present disclosure, the preheating step has a step including: when the flame is preheated to a position 2-4 mm below a welding line at the flaring part, the angle between the flame and the horizontal plane of the welding line is 5-10 degrees; when the flame is adjusted upwards to preheat the welding seam and the area 10-15 mm above the welding seam, the angle between the flame and the horizontal plane of the welding seam is 40-50 degrees, when the color of the welding seam is white, the angle of the flame is adjusted to be 5-10 degrees to slowly preheat the whole welding seam, and the whole welding seam is white.

According to the embodiment of the disclosure, in the step of preheating the position 2-4 mm below the welding line at the flaring part, when the preheating part is slightly white, the step of preheating the welding line and the area 10-15 mm above the welding line is carried out.

According to the embodiment of the disclosure, the steps of adding the brazing filler metal and keeping warm are entered when the whole preheating part is white and the brightness is not increased in the preheating step.

According to the embodiment of the disclosure, the distance between the inner flame and the base material in the preheating step is 15-30 mm; the distance between the inner flame and the base material in the steps of adding the brazing filler metal and preserving heat is 200-250 mm.

According to the embodiment of the disclosure, the angle between the flame and the horizontal plane of the welding seam in the steps of adding the brazing filler metal and preserving heat is 5-10 degrees.

According to the embodiment of the disclosure, in the steps of adding the brazing filler metal and preserving heat, the flame is reciprocated up and down and rotated in the circumferential direction to preserve heat.

According to the embodiment of the disclosure, in the steps of adding the brazing filler metal and preserving heat, the brazing filler metal is added into the welding seam for 2-3 times.

According to an embodiment of the present disclosure, the welding flame is a micro-carbonization flame.

According to the embodiment of the disclosure, the brazing filler metal is copper-based brazing filler metal containing silver, and the diameter and the using amount of the brazing filler metal are determined according to the capacity of a welding seam.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view showing the connection of an expansion valve to a pipe;

FIG. 2 is a cross-sectional view of the expansion valve at the orifice;

FIG. 3 is a schematic view of an expansion valve orifice weld according to an embodiment of the present disclosure;

FIG. 4 is a schematic view of an expansion valve orifice braze flow at a weld joint according to an embodiment of the present disclosure;

in the above figures: 1. an expansion valve; 11. flaring; 2. piping; 3. a restrictor; 4. and (7) welding seams.

Detailed Description

The invention is described in detail below by way of exemplary embodiments. It should be understood, however, that elements, structures and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

FIG. 1 is a schematic view showing the connection of an expansion valve to a pipe; fig. 2 is a cross-sectional view of the orifice of the expansion valve.

Referring to fig. 1 and 2, an expansion valve 1 is an important component of an air conditioner, and a pipe 2 is usually connected to a nozzle of the expansion valve 1 to realize the flow of a refrigerant; in order to throttle and reduce noise, throttlers 3 are arranged in two ends of the pipe orifice of the expansion valve 1.

In order to facilitate the connection and positioning of the expansion valve 1 and the pipe 2, the opening of the expansion valve 1 has a flared end 11, the pipe 2 is inserted into the flared end 11, and a weld between the inner diameter of the flared end 11 and the outer diameter of the pipe 2 is brazed, thereby welding the expansion valve 1 and the pipe 2.

However, since the built-in throttle 3 is not firmly fixed in the pipeline, when the air conditioner is operated for heating, the refrigerant drives the throttle 3 to move up and down, so that the problems of metal impact and friction noise are generated at the expansion valve 1.

In order to solve the problem of noise at the expansion valve 1 when the air conditioner operates, the invention provides a welding method capable of ensuring that the restrictor is firmly fixed at the pipe orifice of the expansion valve 1.

Fig. 3 is a schematic view of an expansion valve nozzle weld according to an embodiment of the present disclosure, and fig. 4 is a schematic view of an expansion valve nozzle filler metal flowing in the weld according to an embodiment of the present disclosure.

Referring to fig. 3 and 4, in order to ensure that the restrictor 3 can be welded during welding, in addition to welding of the weld between the inner diameter of the flared opening 11 and the outer diameter of the pipe 2, the liquid brazing filler metal is required to sequentially flow and fuse in four directions in the weld, the liquid brazing filler metal flows and fuses downward first, then flows and fuses transversely, and finally flows and fuses simultaneously up and down in the secondary weld on the inner side.

Specifically, the welding method of the expansion valve nozzle comprises the following steps:

s1, preheating: preheating a position 2-4 mm below a welding line at a flaring part, and then preheating the welding line and a region 10-15 mm above the welding line by adjusting flame upwards;

s2, adding brazing filler metal and preserving heat: adding brazing filler metal into the welding seam for multiple times to enable the brazing filler metal to be melted, flow and joint filled; and repeatedly moving the flame back and forth to keep the temperature of the welding seam and the range of 10mm above and below the welding seam until the brazing filler metal penetrates to form a welding angle.

Because the throttle is hidden inside, flame can't directly preheat it, and in addition, the expansion valve mouth of pipe and throttle are mostly heterogeneous material, be the red copper material like the expansion valve mouth of pipe, the throttle is the brass material, can't preheat simultaneously two kinds of different materials during the welding, consequently, in order to reach fine preheating effect, preheat the step above, set up preheating position and order: preheating the flaring in the range of 2-4 mm below the welding line and then preheating the welding line and the area above the welding line, directly contacting the outer wall of the throttle at the position of 2-4 mm below the flaring with the inner wall of the pipe at the outer side of the welding line, preheating the position to quickly raise the temperature of the throttle inside the welding line, improving the speed of the whole preheating process, ensuring that the follow-up brazing filler metal can be melted and flow to the position to firmly weld the throttle, and avoiding the problem that the throttle is not firm and generates impact noise.

According to the heat transfer guiding principle between the welding seam structure and the materials, the micro-carbonization flame is used for welding the welding seam in the method, at the moment, the mixing ratio of LPG and oxygen in the welding flame is smaller than 1, the temperature of the welding flame is about 2700 ℃, and a good welding effect can be achieved.

In the whole preheating process, in order to enable the temperature between different materials inside and outside the welding seam to be in a balanced state, the welding process is realized by adjusting the angle of welding flame for many times. In the welding, the expansion valve is vertically fixed in the illustrated state and welded.

Specifically, the S1 preheating step includes: when the position 2-4 mm below a welding line at the flaring position is preheated, the angle between flame and the horizontal plane of the welding line is 5-10 degrees, the circumferential rotation is adopted for preheating, the rotation angle is larger than 120 degrees, the speed is not too high, when the preheating position is slightly white under the visual observation of a sunglasses, the flame is adjusted upwards to preheat the welding line and the area 10-15 mm above the welding line, the angle between the flame and the horizontal plane of the welding line is 40-50 degrees, when the color of the welding line is white under the visual observation of the sunglasses, the angle between the flame and the horizontal plane of the welding line is adjusted to 5-10 degrees to slowly preheat the whole welding line, so that the whole welding line is white, and the brightness is not increased any more.

In the early stage (preheating the position 2-4 mm below a welding seam), the angle between welding flame and the horizontal plane of the welding seam is about 5-10 degrees, the flame can be roughly concentrated below the welding seam due to a small inclination angle, the position can be quickly preheated, and the flame is adjusted upwards after the preheating position is slightly white; in the middle stage (preheating a welding seam and a 10-15 mm area above the welding seam), the angle between welding flame and the horizontal plane of the welding seam is about 40-50 degrees, a large preheating range can be covered, heat is continuously transferred to the lower part of the welding seam while the welding seam part is preheated, the temperature below the welding seam is continuously increased while the welding seam part is preheated, and the temperature imbalance caused by different materials in the welding seam when the welding seam and the upper part and the lower part of the welding seam are directly preheated is avoided; when the color of the welding line is white, the welding line enters a later stage preheating stage, the flame angle is adjusted to be 5-10 degrees for slow preheating, finally the whole preheating range is white, the brightness is not increased any more, and the preheating effect of temperature balance is achieved.

In the steps, when the position 2-4 mm below the welding seam is preheated in the early stage, the preheating position is slightly white and the upward-adjusting flame is switched to the middle stage. When the brass restrictor is whitish, the temperature is increased to the brazing temperature, so that the situation that the position is directly preheated to the brazing temperature is avoided, and the temperature of the position is continuously increased due to heat conduction during the middle and later preheating periods, so that the structure of the brass restrictor in the brass restrictor is influenced; in the middle period, when the welding seam is white and is close to the brazing temperature, the flame angle is adjusted to be a small angle for slowly preheating, so that the temperature of the whole welding seam area is slowly increased to the brazing temperature, and the temperature cannot exceed the brazing temperature due to continuous and quick preheating.

Therefore, according to the welding method disclosed by the invention, the welding flame is subjected to angle adjustment in stages in the whole preheating process, so that the temperature balance rise between different materials inside and outside a welding seam is ensured; and each technological process is visible, controllable and easy to operate, the mass operation of unified welding quality can be realized, the reliable fixation of the throttler in the welding seam is ensured, the noise generated by the fact that the throttler is not fixed and impacts metal in the heating process in the prior art is avoided, and the method has the advantages of balanced temperature in the preheating process, high welding quality and mass operation.

When the S1 preheating reaches the soldering temperature (the color of the welding seam is white and the brightness is not increased), the method proceeds to the step S2 of adding the brazing filler metal and preserving the heat.

In the step of S2 adding solder and maintaining: the brazing filler metal is about 10-20% of silver-containing phosphorus-copper brazing filler metal, the diameter of the brazing filler metal is 3mm, the using amount of the brazing filler metal is 25mm, and the brazing filler metal is added into a welding seam in batches for 2-3 times; and (3) adding brazing filler metal and simultaneously preserving heat: adjusting the angle between the flame and the horizontal plane of the welding seam to be 5-10 degrees, moving the welding seam and the range of 10mm above and below the welding seam up and down and preserving heat in a circumferential rotating way, and observing the infiltration condition of the liquid brazing filler metal until the brazing filler metal infiltrates to form a welding angle.

The control to the brazing filler metal total amount can avoid the problem that volume is excessive when personal operation, volume is little the welding not firm, simultaneously, add brazing filler metal many times and can guarantee that liquid brazing filler metal smoothly flows in that the welding seam is inside, prevent the big excessive problem of the inside liquid brazing filler metal volume of welding seam to and add the problem that brazing filler metal welding seam flow inhomogeneous welding quality is poor.

In some embodiments, in the preheating step of S1, the distance of the inner flame from the parent material is 15mm to 30 mm; s2, in the steps of adding brazing filler metal and preserving heat, the distance between the inner flame and the base metal is 200-250 mm;

if the distance is too close, the base metal is quickly preheated to the brazing temperature, uniform heating of different materials cannot be guaranteed, and the quality of subsequent welding can be affected, namely the liquid brazing filler metal is not uniform at a welding seam; if the distance is too far away, temperature rise is slower, can influence production efficiency, consequently, this disclosure has set up the distance of flame and base metal in each step, can guarantee the thermally equivalent of base metal, can guarantee welded high efficiency simultaneously.

This disclosed embodiment makes the expansion valve mouth of pipe can reach the welding target shown in fig. 3 through the setting to welding flame, distance, angle, the interpolation number of times isoparametric of brazing filler metal, the throttle is firm to be fixed in the inside of welding seam, this effect is realized when welding expansion valve mouth of pipe and piping, need not to increase new structure, part and process for the fixed of throttle, the fixed target of throttle has been reached under the prerequisite that does not increase the cost, product quality is improved, the noise of expansion valve mouth of pipe department has been avoided.

In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A method for welding an expansion valve orifice is characterized by comprising the following steps: the expansion valve comprises an expansion valve, a pipe and a restrictor, wherein a pipe opening of the expansion valve is provided with a flared opening, the end part of the pipe is inserted into the flared opening, a welding seam is formed between the flared opening and the pipe, and the restrictor is positioned in the connection part of the pipe opening of the expansion valve and the pipe;

the welding method comprises the following steps:

preheating: preheating a position 2-4 mm below a welding line at a flaring part, and then preheating the welding line and a region 10-15 mm above the welding line by adjusting flame upwards;

adding brazing filler metal and preserving heat: adding brazing filler metal into the welding seam to enable the brazing filler metal to be melted, flow and joint filled; and repeatedly moving the flame back and forth to keep the temperature of the welding seam and the range of 10mm above and below the welding seam until the brazing filler metal penetrates to form a welding angle.

2. The welding method of claim 1, wherein the preheating step comprises: when the flame is preheated to a position 2-4 mm below a welding line at the flaring part, the angle between the flame and the horizontal plane of the welding line is 5-10 degrees; when the flame is adjusted upwards to preheat the welding seam and the area 10-15 mm above the welding seam, the angle between the flame and the horizontal plane of the welding seam is 40-50 degrees, and when the color of the welding seam is white, the angle between the flame is adjusted to 5-10 degrees to slowly preheat the whole welding seam.

3. The welding method according to claim 1, wherein in the step of preheating the position 2-4 mm below the welding seam at the flaring part, when the preheating part is whitish, the step of preheating the welding seam and the area 10-15 mm above the welding seam is carried out.

4. The welding method according to claim 1, wherein the steps of adding the brazing filler metal and maintaining the temperature are performed when the entire preheating portion is white and the brightness is not increased in the preheating step.

5. The welding method according to claim 1, wherein a distance of the inner flame from the base material in the preheating step is 15 to 30 mm; the distance between the inner flame and the base material in the steps of adding the brazing filler metal and preserving heat is 200-250 mm.

6. The welding method according to claim 1, wherein the angle of the flame with the horizontal plane of the weld in the brazing filler metal adding and holding steps is 5 ° to 10 °.

7. The welding method according to claim 1, wherein the brazing filler metal is added to the weld in 2 to 3 times in the brazing filler metal adding and heat insulating steps.

8. The welding method according to claim 1, wherein the step of adding the brazing filler metal and maintaining the temperature is performed by reciprocating upward and downward and rotating the flame in a circumferential direction.

9. The welding method of claim 1, wherein the welding flame is a micro-carbonization flame.

10. The welding method according to claim 1, wherein the brazing filler metal is a copper-based brazing filler metal containing silver, and the diameter and the amount of the brazing filler metal are determined in accordance with the capacity of the weld.