Method and process for welding asymmetric J-shaped grooves of thin-walled tube and plate

Abstract

The invention relates to the technical field of pipe and plate welding, in particular to a welding method for asymmetric J-shaped grooves of thin-walled pipes and plates. The welding method for the asymmetric J-shaped groove of the thin-walled tube and the plate specifically comprises the following steps that S1, assembly spot welding and backing welding are conducted, specifically, spot welding is conducted in the 6H-3H-9H-12H direction, and then backing welding is conducted alternately in the 6H-3H / 9H-12H direction; s2, filling a lower half part: filling a 6H + / -4.5 H area, alternately welding left and right according to a 6H-3H-1.5 H direction and a 6H-9H-10.5 H direction for each path, welding 3-4 layers, and during welding of each layer, firstly welding a groove close to an end socket side area, then welding a groove close to a sleeve side area, and reducing heat input on the sleeve; and S3, the upper half part is filled, specifically, the 12H + / -1.5 H area is filled, welding is conducted left and right alternately in the 10.5 H-12H direction and the 1.5 H-12H direction, welding is conducted for 3-4 layers, during welding of each layer, the portion, close to the end socket side area, of the groove is welded firstly, then the portion, close to the sleeve side area, of the groove is welded, and heat input on the sleeve is reduced. The method has the advantage that the welding deformation direction and the deformation amount can be effectively controlled.

Description

Technical Field

[0001] The invention relates to the technical field of pipe and plate welding, and in particular to a welding method and process for a thin-wall pipe and a plate with an asymmetric J-shaped groove. Background Art

[0002] As one of the main equipment of the primary circuit of a nuclear power plant, the function of the pressurizer is to maintain the primary circuit pressure at a constant pressure when the power plant is in operation. The electric heater element of the lower head assembly is a key component for the pressurizer to achieve primary circuit pressure regulation. When the nuclear power plant is operating normally, the heating and regulation function of the electric heater assembly can be maximized to reduce the action of other safety systems (such as spray and up-and-down discharge systems). The electric heater element consists of two parts: the electric heater sleeve and the electric heater. The connection method with the lower head is: first weld the electric heater sleeve and the lower head with a J-shaped groove weld, and then pass the electric heater through the heater sleeve into the interior of the pressurizer. The electric heater sleeve / electric heater is distributed in 4 circles on the lower head (such as Figure 1 Each circle has a different number of electric heater elements, totaling more than 100 pieces, which are assembled vertically with the lower head.

[0003] Lower head: thickness 120mm, low alloy high strength steel 18MND5, inner surface is welded with about 20mm thick austenitic stainless steel (309L+308L) as corrosion resistant layer.

[0004] Heater sleeve: stainless steel Z2CND18.12 (N), thickness 6.3mm, inner diameter 23.6mm.

[0005] According to the outer diameter of the electric heater and the inner diameter of the sleeve, when the electric heater penetrates the inner wall of the electric heater sleeve, the theoretical gap between them is only 0.7mm. The design requires that after the sleeve and the head are welded, the electric heater can safely pass through the sleeve into the inside of the voltage stabilizer without getting stuck or damaging the parent material. Therefore, it is necessary to conduct a rod inspection after the electric heater sleeve is welded. The outer diameter of the rod is set to 22.55mm, which requires that the shrinkage deformation of any quadrant of the electric heater sleeve after welding with the lower head shall not be greater than 0.425mm.

[0006] The connection between the electric heater sleeve and the lower head is an asymmetric J-shaped groove weld (for details on the specific groove type and weld size, see Figure 2), the sleeve is made of austenitic stainless steel. Stainless steel has the characteristics of low thermal conductivity, strong thermal sensitivity, and large expansion coefficient, which is very easy to cause welding deformation. The sleeve wall thickness is only 6.3mm, and the rigidity is poor. At the same time, the welding filling volume is large, and the heat accumulation will further aggravate the welding shrinkage. The above situation determines that the welding of this weld will easily produce large welding deformation. At the same time, the diameter of the weld between the sleeve and the head is small, the groove is asymmetric, and the welding is difficult. Since this weld is the main pressure-bearing weld, the design requires that the base weld and every three layers of welds must pass the PT flaw detection, and the weld quality requirements are high. Therefore, while ensuring the quality of the J-type weld between the sleeve and the lower head, controlling the welding deformation and ensuring the smooth passage of the electric heater are the top priorities in the manufacture of voltage stabilizer products.

[0007] When the electric heater sleeve and the lower head are welded, since the head is hemispherical and the sleeve is welded vertically, there is a height difference between the upper and lower sides of the groove, and the groove of the weld is larger at the top and smaller at the bottom (see Figure 2 ), as the distance from the sleeve to the axis of the head increases, the height difference also increases, and the difference between the welding volume at the low and high places becomes larger and larger. The asymmetric welding volume will aggravate the severity of welding deformation. According to the prior art, although certain measures have been taken in terms of welding process and operation to control welding deformation as much as possible, the asymmetric shrinkage of the high and low parts of the weld still causes the pipe mouth to produce deformation exceeding the design requirements (≤0.425mm), which is mainly manifested in the overall deformation of the sleeve toward the 12 o'clock direction where the welding volume is larger, resulting in the jamming of the through rod near the 6 o'clock position. Each voltage stabilizer product has a total of 108 electric heaters, and about 95% of the electric heaters cannot be passed into the sleeve during assembly. Schematic diagram of through rod jamming caused by welding deformation in the prior art is shown in Figure 2 shown.

[0008] The disadvantage of the prior art is that only certain measures are implemented from the perspective of controlling the overall welding deformation, which reduces the welding deformation shrinkage and ensures the weld quality to a certain extent, but the control measures taken still cannot control the welding deformation within the design requirements (i.e. ≤0.425mm), and the problem of asymmetric J-groove weld deformation in a single direction is not solved, resulting in the jamming of the through rod and failure to meet the design requirements.

[0009] Therefore, in view of the deficiencies in the prior art, a method for welding a thin-walled tube and a plate with an asymmetric J-shaped groove is provided. Summary of the invention

[0010] In order to overcome the deficiencies of the prior art, the present invention provides a method and process for welding asymmetric J-shaped grooves of thin-walled tubes and plates, aiming to solve the problems of overall deformation of the casing in a single direction and large deformation after welding.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A method for welding asymmetric J-shaped grooves of a thin-walled tube and a plate comprises the following steps:

[0013] S1: Assembly spot welding and base welding: spot welding is performed in the direction of 6H→3H→9H→12H, and then base welding is performed alternately in the direction of 6H→3H / 9H→12H;

[0014] S2: Fill the lower part: fill the 6H±4.5H area, and weld alternately from left to right in the direction of 6H→3H→1.5H and 6H→9H→10.5H. Weld 3-4 layers. When welding each layer, first weld the groove close to the head side area, and then weld the area close to the casing side area;

[0015] S3: Fill the upper part: fill the 12H±1.5H area, and weld alternately from left to right in the direction of 10.5H→12H and 1.5H→12H. Weld 3-4 layers. When welding each layer, first weld the groove close to the head side area, and then weld the area close to the casing side area.

[0016] As a further improvement of the technical solution of the present invention, in step S1: a layer of base welding is performed in a whole circle, and a penetrant inspection is performed on the base layer weld.

[0017] As a further improvement of the technical solution of the present invention, in step S1: the base welding is performed alternately left and right in the directions of 6H→3H→12H and 6H→9H→12H.

[0018] As a further improvement of the technical solution of the present invention, in step S2: after welding is completed, the overlap is ground and a liquid penetration inspection is performed.

[0019] As a further improvement of the technical solution of the present invention, in step S3: after welding is completed, the overlap is ground and a liquid penetration inspection is performed.

[0020] The invention discloses a welding process for asymmetric J-shaped grooves of a thin-walled tube and a plate, which is suitable for the above-mentioned welding method for asymmetric J-shaped grooves of a thin-walled tube and a plate, and manual tungsten inert gas arc welding is adopted for welding.

[0021] As a further improvement of the technical solution of the present invention, it includes controlling the welding parameters: the diameter of the welding wire is 1.2-1.6 mm, the welding current is 120-130 A, and the welding speed is 8 cm / min-10 cm / min.

[0022] As a further improvement of the technical solution of the present invention, it also includes controlling the inter-pass temperature: a water cooling device is set to control the inter-pass temperature between 45°C and 55°C, and a water cooling device is set to assist in cooling the temperature, which can be reduced to the above temperature about 15 seconds after each welding pass is completed, thereby improving welding efficiency.

[0023] As a further improvement of the technical solution of the present invention, the water cooling device is detachably connected to the heater sleeve;

[0024] The water cooling device comprises a water supply device, a water spray head, an inclined sleeve, a water flow head, a water supply pipe, a tensioning member and a connector;

[0025] The inclined sleeve is located above the heater sleeve, the water spray head penetrates the inclined sleeve and then extends into the heater sleeve, the water flow head is connected to the water spray head, the water supply pipe connects the water flow head and the connecting head, the other end of the connecting head is connected to the water supplier, the tensioning piece is abutted against the heater sleeve, the connecting head is abutted against the tensioning piece through a nut, and the connecting head is connected to the water supplier.

[0026] As a further improvement of the technical solution of the present invention, the water spray head is provided with a plurality of through holes, and the plurality of through holes connect the interior of the water spray head with the inner wall of the heater sleeve.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] In the welding method of the thin-walled tube and the plate with asymmetric J-shaped groove of the present invention, under the premise of symmetrical welding on the left and right sides, the asymmetric channeling method for the upper and lower side welding can effectively control the welding deformation direction, that is, only the lower half is welded first, and the sleeve is fixed in a normal position as a whole by the strength of the weld of the lower half, so as to offset the effect of welding stress when the upper half is filled later, and avoid the overall deformation of the sleeve, solve the problem of the overall deformation of the sleeve in a single direction after welding, and control the deformation shrinkage of the weld in any direction within 0.425mm, thereby solving the problem of the sticking of the rod, so that the electric heater 21 of the product can finally pass smoothly. The welding method of the thin-walled tube and the plate with asymmetric J-shaped groove has the characteristics of effectively controlling the welding deformation direction and deformation amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The technology of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0030] Figure 1 It is a schematic diagram of the structure of the thin-walled tube and the plate of the present invention;

[0031] Figure 2 It is a schematic diagram of the deformation and rod blocking after welding of the asymmetric J-shaped groove of the thin-walled tube and the plate under the prior art;

[0032] Figure 3 It is a schematic diagram of the bottoming of the welding method of the asymmetric J-shaped groove of the thin-walled tube and the plate of the present invention;

[0033] Figure 4 It is a top view of the spot welding and bottoming sequence of the welding method of the asymmetric J-shaped groove of the thin-walled tube and the plate of the present invention;

[0034] Figure 5 It is a schematic diagram of the filling of the lower half of the method for welding asymmetric J-shaped grooves of thin-walled tubes and plates of the present invention;

[0035] Figure 6 It is a top view of the filling sequence of the lower half of the method for welding asymmetric J-shaped grooves of a thin-walled tube and a plate according to the present invention;

[0036] Figure 7 It is a filling deformation trend diagram of the lower half of the method for welding asymmetric J-shaped grooves of thin-walled tubes and plates of the present invention;

[0037] Figure 8 It is a schematic diagram of the upper half of the filling of the method for welding asymmetric J-shaped grooves of a thin-walled tube and a plate according to the present invention;

[0038] Fig. 9 It is a top view of the filling sequence of the upper half of the method for welding asymmetric J-shaped grooves of a thin-walled tube and a plate according to the present invention;

[0039] Fig.10 It is a filling deformation trend diagram of the upper half of the method for welding asymmetric J-shaped grooves of thin-walled tubes and plates of the present invention;

[0040] Fig.11 The present invention is a schematic structural diagram of a water cooling device in a method for welding asymmetric J-shaped grooves of a thin-walled tube and a plate.

[0041] In the figure:

[0042] 1. Lower head;

[0043] 2. Heater sleeve; 21. Electric heater;

[0044] 3. Welding seam;

[0045] 4. Water cooling device; 41. Water spray head; 42. Through hole; 43. Oblique sleeve; 44. Water supply head; 45. Water supply pipe; 46. Tension piece; 47. Connector;

[0046] 5. Tongbang. DETAILED DESCRIPTION

[0047] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention, so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other without conflict. The same reference numerals used throughout the drawings indicate the same or similar parts.

[0048] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature, or it may be indirectly fixed or connected to the other feature. In addition, the descriptions of up, down, left, right, etc. used in the present invention are only relative to the relative positional relationship of the components of the present invention in the drawings.

[0049] Reference Figures 1 to 11 A method for welding a thin-walled tube and a plate with an asymmetric J-shaped groove comprises the following steps:

[0050] S1: Assembly spot welding and base welding: spot weld 4 places in the direction of 6H→3H→9H→12H, then base weld alternately in the direction of 6H→3H / 9H→12H, that is, weld alternately in the direction of 6H→3H→12H and 6H→9H→12H;

[0051] S2: Fill the lower part: fill the 6H±4.5H area, and weld each pass alternately from left to right from bottom to top, that is, weld alternately from left to right in the direction of 6H→3H→1.5H and 6H→9H→10.5H, and weld 3-4 layers; when welding each layer, first weld the area close to the head side of the groove, and then weld the area close to the casing side to reduce the heat input on the casing;

[0052] S3: Fill the upper part: fill the 12H±1.5H area, and weld each pass alternately from left to right from bottom to top, that is, weld alternately in the direction of 10.5H→12H and 1.5H→12H, and weld 3-4 layers; when welding each layer, first weld the groove close to the head side area, and then weld the area close to the casing side to reduce the heat input on the casing.

[0053] Among them, under the premise of symmetrical welding on the left and right sides, the asymmetric channel method for welding the upper and lower sides can effectively control the direction of welding deformation, that is, only the lower half is welded first, and the strength of the weld 3 in the lower half fixes the sleeve in a normal position as a whole, so as to offset the effect of welding stress during subsequent filling of the upper half, and avoid overall deformation of the sleeve. On the basis of ensuring the quality of the asymmetric J-groove weld 3 between the heater sleeve 2 and the lower head 1, the overall welding deformation of the weld 3 is further reduced, solving the problem of overall deformation of the sleeve in a single direction after welding, and controlling the deformation shrinkage of the weld 3 in any direction within 0.425mm, thereby solving the problem of the stick 5 being stuck, and finally allowing the electric heater 21 of the product to pass smoothly. The welding method of the asymmetric J-groove of the thin-walled tube and the plate has the characteristics of effectively controlling the direction and amount of welding deformation.

[0054] In one embodiment, referring to Figure 3-Figure 4As shown, in step S1: a layer of base welding is performed in the whole circle, and a visual inspection and liquid penetration inspection are performed on the base layer of the weld 3. If only a part of the base layer is welded, when performing PT flaw detection, PT liquid enters the gap between the casing and the head and cannot be cleaned. In addition, during subsequent welding, impurities such as slag will also enter the gap between the casing and the head, which is difficult to clean, and the quality of the weld 3 cannot be guaranteed.

[0055] In one embodiment, referring to Figure 5-Figure 7 As shown, in step S2: fill the 6H±4.5H area, and weld each pass alternately in the 6H→3H→1.5H direction and the 6H→9H→10.5H direction, and weld 3-4 layers; when welding each layer, first weld the groove close to the head side area, and then weld the area close to the casing side to reduce the heat input on the casing. After welding, grind the overlap and perform a liquid penetration inspection.

[0056] In one embodiment, referring to Figure 8 to Figure 10 In step S3: fill the 12H±1.5H area, and weld each pass alternately in the 10.5H→12H direction and the 1.5H→12H direction, and weld 3-4 layers; when welding each layer, first weld the groove close to the head side area, and then weld the area close to the casing side to reduce the heat input on the casing. After welding, grind the overlap and perform a liquid penetration inspection.

[0057] In one embodiment, the control of the filling amount of the lower half is as follows: through multiple tests, it has been proved that the welding amount is about 3 / 4 circle, and 3 to 4 layers are welded, which can better play the role of controlling deformation. If the welding amount is less than 3 / 4 circle or the number of layers is not enough, the welding fixing effect is not enough to withstand the stress effect during the welding of the upper half, and the overall sleeve will still be deformed towards the 12 o'clock direction after the upper half is welded. If the welding exceeds 3 / 4 circle, due to structural limitations, the arc closing area of ​​the lower half is difficult to polish clean, and defects are likely to occur during the subsequent welding of the upper half, which is not conducive to the control of the quality of the weld 3.

[0058] The invention discloses a welding process for asymmetric J-shaped grooves of thin-walled tubes and plates, which is applicable to the above-mentioned welding method for asymmetric J-shaped grooves of thin-walled tubes and plates. The invention adopts a welding method with a small heat input and adopts manual tungsten inert gas arc welding.

[0059] In one embodiment, the welding process includes controlling welding parameters to reduce welding heat input: the welding wire diameter is selected to be 1.2-1.6 mm, and the welding current is 120-130 A. When the welding current exceeds this range, the heat input is large, and the effect of accurately controlling the welding deformation cannot be achieved. The base material of the lower head 1 is thick, and the current is less than this range, which affects the formation of the weld 3 and cannot guarantee the quality of the weld 3. Based on this current, the welding speed is controlled to 8cm / min-10cm / min. When the welding speed is less than this range, the heat input is large, which is not conducive to welding deformation control. When it exceeds this range, the weld 3 is poorly formed and the quality of the weld 3 cannot be guaranteed.

[0060] In one embodiment, the welding process also includes controlling the interpass temperature: since the lower the interpass temperature, the more conducive it is to controlling welding deformation, but this means that a long waiting time is required after each welding pass is completed, which reduces product manufacturing efficiency. After many simulation tests, by setting a water cooling device 4 to control the interpass temperature between 45°C and 55°C, the post-welding deformation can meet the design requirements.

[0061] In one embodiment, referring to Fig.11 As shown, the water cooling device 4 is detachably connected to the heater sleeve 2. Water cooling during welding can quickly remove the heat generated during welding, reduce residual stress, and increase the cooling rate during welding. It can not only make the weld 3 have fine metal grains, uniform structure, and small welding residual stress to obtain an ideal welded joint, but also reduce the residence time of the welded joint at high temperature and reduce welding deformation. To this end, we have developed a special water cooling device 4, and at the same time, a wet towel is used to wipe the head side for cooling. After implementing this measure, the actual product can be reduced to about 50°C in about 15 seconds after each welding is completed, which is not only conducive to the control of welding deformation, but also greatly improves production efficiency.

[0062] In one embodiment, the water cooling device 4 includes a water supply device, a water spray head 41, an inclined sleeve 43, a water supply head 44, a water supply pipe 45, a tensioning member 46 and a connector 47; the inclined sleeve 43 is located above the heater sleeve 2, the water spray head 41 penetrates the inclined sleeve 43 and then extends into the heater sleeve 2, the water supply head 44 is connected to the water spray head 41, the water supply pipe 45 connects the water supply head 44 with the connector 47, the other end of the connector 47 is connected to the water supply device, the tensioning member 46 abuts against the heater sleeve 2, the connector 47 abuts against the tensioning member 46 through a nut, and the connector 47 is connected to the water supply device. When the water cooling device 4 is cooling down, the water supply device supplies cooling water from bottom to top to the water spray head 41 through the connector 47 and the water supply pipe 45, and the heater sleeve 2 is cooled down through the water spray head 41.

[0063] In one embodiment, the water spray head 41 is provided with a plurality of through holes 42 , and the plurality of through holes 42 connect the interior of the water spray head 41 with the inner wall of the heater sleeve 2 , and the cooling water cools the inner wall of the heater sleeve 2 through the through holes 42 .

[0064] In one embodiment, the control of welding sequence, the control of welding parameters and the design of water-cooling tooling are three indispensable aspects. With the synergistic effect of the three aspects, the weld 3 between the heater sleeve 2 and the lower head 1 can solve the problem of deformation of the weld 3 in a single direction while ensuring the welding quality, and the deformation shrinkage in any direction is controlled within 0.425mm, so that all 108 electric heaters 21 of the product finally pass smoothly and meet the product design requirements.

[0065] The other contents of the welding method and process of the asymmetric J-shaped groove of the thin-walled tube and the plate described in the present invention can be found in the prior art and will not be described in detail here.

[0066] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Therefore, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention are still within the scope of the technical solution of the present invention.

[0067] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0068] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A method for welding asymmetric J-shaped grooves of thin-walled tubes and plates, characterized in that: The following steps are involved: S1: Assembly spot welding and base welding: spot welding is performed in the direction of 6H→3H→9H→12H, and then base welding is performed alternately in the direction of 6H→3H / 9H→12H; S2: Fill the lower part: fill the 6H±4.5H area, and weld alternately from left to right in the direction of 6H→3H→1.5H and 6H→9H→10.5H. Weld 3-4 layers. When welding each layer, first weld the groove close to the head side area, and then weld the area close to the casing side area; S3: Fill the upper part: fill the 12H±1.5H area, and weld alternately from left to right in the direction of 10.5H→12H and 1.5H→12H. Weld 3-4 layers. When welding each layer, first weld the groove close to the head side area, and then weld the area close to the casing side area.

2. A method for welding asymmetric J-shaped grooves of thin-walled tubes and plates according to claim 1, characterized in that: In step S1: a layer of base welding is performed in the entire circle, and a penetration test is performed on the base layer weld.

3. A method for welding asymmetric J-shaped grooves of thin-walled tubes and plates according to claim 2, characterized in that: In step S1: the bottom welding is performed alternately in the directions of 6H→3H→12H and 6H→9H→12H.

4. A method for welding asymmetric J-shaped grooves of thin-walled tubes and plates according to claim 1, characterized in that: In step S2: after welding is completed, the overlap is ground and a liquid penetrant inspection is performed.

5. The method for welding asymmetric J-shaped grooves of thin-walled tubes and plates according to claim 1, characterized in that: In step S3: after welding is completed, the overlap is ground and a liquid penetrant inspection is performed.

6. A welding process for a thin-walled tube and a plate with an asymmetric J-shaped groove, applicable to the welding method for a thin-walled tube and a plate with an asymmetric J-shaped groove as claimed in any one of claims 1 to 5, characterized in that: The welding is done by manual tungsten inert gas welding.

7. A welding process for asymmetric J-shaped groove of a thin-walled tube and plate according to claim 6, characterized in that: Including controlling welding parameters: welding wire diameter is 1.2-1.6mm, welding current is 120-130A, and welding speed is 8cm / min-10cm / min.

8. A welding process for asymmetric J-shaped groove of a thin-walled tube and plate according to claim 6, characterized in that: It also includes controlling the inter-pass temperature: controlling the inter-pass temperature between 45°C and 55°C, and setting up a water cooling device to assist in cooling. It can be reduced to the above temperature about 15 seconds after each welding pass is completed, thereby improving welding efficiency.

9. A welding process for asymmetric J-shaped groove of a thin-walled tube and plate according to claim 8, characterized in that: The water cooling device is detachably connected to the heater sleeve; The water cooling device comprises a water supply device, a water spray head, an inclined sleeve, a water flow head, a water supply pipe, a tensioning member and a connecting head; The inclined sleeve is located above the heater sleeve, the water spray head penetrates the inclined sleeve and then extends into the heater sleeve, the water flow head is connected to the water spray head, the water supply pipe connects the water flow head and the connecting head, the other end of the connecting head is connected to the water supplier, the tensioning piece is abutted against the heater sleeve, the connecting head is abutted against the tensioning piece through a nut, and the connecting head is connected to the water supplier.

10. A welding process for asymmetric J-shaped groove of a thin-walled tube and plate according to claim 9, characterized in that: The water spray head is provided with a plurality of through holes, and the plurality of through holes communicate with the interior of the water spray head and the inner wall of the heater sleeve.

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