Diffusion through-flow device for welding of stainless steel water box body of steam turbine generator and use method of diffusion through-flow device

Abstract

The invention belongs to the technical field of turbonator stainless steel water box bodies, and particularly relates to a diffusion through-flow device for turbonator stainless steel water box body welding and a using method of the diffusion through-flow device. According to the technical scheme, the diffusion through-flow device for welding the stainless steel water box body of the steam turbine generator comprises a locking mechanism used for clamping the water box body and a connecting plate, a gas diffusion core used for introducing shielding gas is inserted into the water box body, and a plurality of gas outlet holes are formed in the section, extending into the water box body, of the gas diffusion core; the air outlet is communicated with an inner cavity of the gas diffusion core, a sealing mechanism is connected between the gas diffusion core and the water box body, and protective gas introduced from the gas diffusion core is diffused to the water box body and then flows out along a gap between the water box body and the connecting plate and the hollow strand channel. The invention provides a diffusion through-flow device for welding a stainless steel water box body of a steam turbine generator and a use method of the diffusion through-flow device.

Description

Technical Field

[0001] The invention belongs to the technical field of stainless steel water box bodies of steam turbine generators, and particularly relates to a diffusion flow device used for welding stainless steel water box bodies of steam turbine generators and a use method thereof. Background Art

[0002] The stator coils of nuclear power and million-class steam turbine generators adopt a water-cooled structure. There are several stainless steel hollow strands 3 inside the wire rod, and the stainless steel water box 1 at the end collects the water flow of the hollow strands 3 together. Figure 6 As shown, at the end of the stator wire rod, the welding of the stainless steel water box body 1 and the stainless steel connecting plate 2 needs to be completed. When the unit is running, the stainless steel hollow strands 3 in the stator wire rod flow deionized water to cool the wire rod, which requires that the deionized water must not have any oxidizing foreign matter remaining, and the hollow strands 3 must not have any foreign matter to cause clogging. Therefore, the weld between the stainless steel water box body 1 and the stainless steel connecting plate 2 must withstand the pressure of the circulating cooling water, and the welding process is not allowed to produce black slag caused by high-temperature oxidation of stainless steel. Otherwise, once the water circuit for cooling the unit is leaking, blocked, or other abnormalities occur, it will cause abnormal temperature rise during operation, and serious operation accidents may also occur.

[0003] like Figure 7 As shown in the figure, the end of the stator bar is welded with multiple stainless steel hollow strands 3 and the connecting plate 2 to form an assembly of about 10m in length. The excessive length and irregular shape make it impossible to weld the stainless steel water box body 1 and the stainless steel connecting plate 2 on the automatic welding equipment. Therefore, for the welding of the two, we can only use manual tungsten inert gas arc welding to complete the welding. Therefore, argon protection during the welding process becomes the core link of manufacturing.

[0004] like Figure 8 As shown, after the stainless steel water box body 1 and the stainless steel connecting plate 2 are attached, they form a welded structure with a semi-enclosed cavity. The existing welding method relies on manually attaching the water box body 1 and the connecting plate 2, and then inserting a soft air pipe into the threaded hole of the water box body 1 to directly pass argon gas to achieve air replacement. This method is not only inefficient, but also has two major risks:

[0005] First, although the argon gas is introduced into the inner cavity of the box body, the ventilation direction is the same as that of the 8 stainless steel hollow strands 3 on the connecting plate 2, forming a straight-through channel. If the argon gas is introduced at a low speed, it will be released directly along the pipeline of the hollow strands 3. If the argon gas is introduced at a high speed, a pressure difference will be generated in the cavity due to the "Bernoulli principle", and more air will be sucked in. It is impossible to form an effective argon gas protection environment for the part where the side wall of the water box body 1 and the connecting plate 2 need to be welded, resulting in local oxidation of the stainless steel in the high temperature environment of welding to produce black slag, and the internal space is limited and cannot be cleaned.

[0006] Second, the uneven gap between the water box body 1 and the connecting plate 2 which are attached by hand will lead to uneven thickness of the weld and insufficient local strength, resulting in the risk of water leakage.

[0007] For a long time, the stator wire bar manufacturing process has often encountered problems such as black slag in the inner cavity and leakage during pressure tests, and even multiple repairs have occurred. This is also a technical bottleneck in the stator wire bar production and manufacturing process. Summary of the invention

[0008] In order to solve the above problems existing in the prior art, the object of the present invention is to provide a diffusion flow device for welding a stainless steel water box body of a steam turbine generator and a method of using the same.

[0009] The technical solution adopted by the present invention is:

[0010] A diffusion flow device for welding a stainless steel water box body of a steam turbine generator comprises a locking mechanism for clamping the water box body and a connecting plate, a gas diffusion core for introducing a protective gas is inserted into the water box body, a section of the gas diffusion core extending into the water box body is provided with a plurality of air outlets, the air outlets are communicated with an inner cavity of the gas diffusion core, a sealing mechanism is connected between the gas diffusion core and the water box body, and the protective gas introduced from the gas diffusion core diffuses into the water box body and then flows out along the gap between the water box body and the connecting plate and the hollow strand passage.

[0011] The water box body is aligned with the stainless steel connecting plate at the end of the stator wire rod, and the locking mechanism is used to position the water box body and adjust the gap between the water box body and the connecting plate to meet the requirements of manual argon arc welding. The gas diffusion core is inserted into the water box body and sealed with a sealing mechanism.

[0012] According to the spatial structural characteristics of the water box body cavity and the direction of gas escape from the cavity, different gas escape channels are designed on the gas diffusion core, and under the premise of avoiding the pressure difference in the cavity due to the "Bernoulli principle", the shielding gas entering the cavity is layered at a low flow rate through turbulent displacement, and turbulent flow with irregular pulsating vortex characteristics is formed through reflection of the water box body cavity wall. This turbulent shielding gas under low-speed conditions forms a slight positive pressure in the water box body cavity, quickly diffuses to the entire water box body cavity, and then flows out along the gap between the water box body and the connecting plate and the hollow strand passage to complete the air replacement in the cavity. After the air in the water box body is fully replaced, the water box body and the stainless steel connecting plate are welded.

[0013] The diffusion flow device of the present invention can pass the protective gas into the water box body. After the air in the water box body is fully replaced by the protective gas, the water box body is welded, which can form an effective argon gas protection environment for the parts where the side wall of the water box body and the connecting plate need to be welded, ensuring that the inside of the water box body is clean and free of foreign matter, and the weld is well fused. The locking mechanism can press the water box body and the connecting plate tightly, ensuring that the gap between the water box body and the connecting plate is more uniform during welding, avoiding the risk of water leakage due to uneven thickness of the weld and insufficient local strength.

[0014] As a preferred solution of the present invention, the section of the gas diffusion core extending into the water box body is a polyhedron, and each face of the polyhedron is provided with an air outlet.

[0015] As a preferred embodiment of the present invention, the air outlet holes on the polyhedron include a plurality of straight air outlet holes parallel to the bottom surface of the water box body and a plurality of oblique air outlet holes obliquely upward relative to the bottom surface of the water box body, and the plurality of straight air outlet holes and the plurality of oblique air outlet holes are arranged at intervals.

[0016] As a preferred solution of the present invention, the air outlet hole is a threaded hole.

[0017] As a preferred solution of the present invention, one end of the gas diffusion core away from the water box body is connected to a hose.

[0018] As a preferred solution of the present invention, an anti-rotation surface is provided on a section of the gas diffusion core extending out of the water box body.

[0019] The gas diffusion core is made of copper material, and the bottom is processed into a polyhedron. A group of straight air outlets are arranged circumferentially on the polyhedron, and a group of oblique air outlets are arranged at intervals. The air outlets are connected to the inner cavity of the gas diffusion core.

[0020] The shielding gas is evenly dispersed after entering the gas diffusion core. The gas from the oblique outlet hits the oblique wall of the water box body and impacts the gas from the straight outlet. The outlet hole is a threaded hole, and the air flow rotates through it, so that the shielding gas stays in the water box body for a longer time, fully replacing the air inside the water box body to form a shielding gas environment. Compared with the direct insertion of the hose, it saves more shielding gas.

[0021] The end of the gas diffusion core can be connected to the hose, and an anti-rotation surface is arranged in the middle section. The anti-rotation surface is a plane to prevent the gas diffusion core from rotating during the tightening process of the back-tightening nut.

[0022] As a preferred embodiment of the present invention, a pipe joint is fixed on the water box body, a step surface is provided inside the pipe joint, a positioning cylinder is provided on the gas diffusion core, the gas diffusion core is inserted into the water box body from the pipe joint, the positioning cylinder overlaps the step surface of the pipe joint, and the sealing mechanism includes a back-tightening nut, which is threadedly connected to the pipe joint, and the back-tightening nut presses the positioning cylinder.

[0023] As a preferred solution of the present invention, a stopper is provided on the back-tightening nut, and the stopper is pressed tightly against an end of the positioning cylinder away from the water box body.

[0024] The thread of the back-tightening nut matches the thread of the water box body. One side of the back-tightening nut has a stopper for locking the gas diffusion core to prevent the gas diffusion core from shaking and to form a seal between the gas diffusion core and the water box body pipe joint.

[0025] As a preferred embodiment of the present invention, the locking mechanism includes a locking hook, which is a door-type frame structure. The hook body of the locking hook buckles the side of the connecting plate away from the water box body. A locking bolt is threadedly connected to the locking hook, and the locking bolt contacts the side of the water box body away from the link plate. The hook body of the locking hook and the locking bolt press the water box body and the connecting plate together.

[0026] The locking hook is a door-shaped frame structure with a screw hole on the top, which is matched with the locking bolt. When in use, the hook supports the water box body and the connecting plate to meet the welding gap requirements. The locking bolt and the locking hook are used together. By tightening the locking bolt, the locking hook presses against the water box body to achieve temporary fixation of the water box body and the connecting plate.

[0027] A method for using a diffusion flow device for welding a stainless steel water box body of a steam turbine generator comprises the following steps:

[0028] S1: First, put the back-tightening nut on the gas diffusion core, and then connect the protective gas source hose to the tail end of the gas diffusion core;

[0029] S2: Insert the gas diffusion core into the inner hole of the water box body, put the back-tightening nut on the pipe joint of the water box body, and tighten the back-tightening nut to form a seal between the gas diffusion core and the water box body;

[0030] S3: Align the water box body with the connecting plate at the end of the stator wire bar, use the locking hook and locking bolt to position, and adjust the gap between the water box body and the connecting plate to meet the requirements of manual argon arc welding;

[0031] S4: Introduce shielding gas into the gas diffusion core. After the air in the water box body is fully replaced, spot weld the water box body and the connecting plate. During the welding process, the shielding gas of the water box body is kept in a slightly positive pressure state. The welds of the water box body and the connecting plate are welded in sequence.

[0032] S5: Loosen the locking bolt, remove the locking hook, and weld the remaining weld under a protective gas environment until the entire circle is fully welded;

[0033] S6: After welding, the protective gas is continuously introduced at a low speed to cool the workpiece. When the workpiece is cooled to below 100°C, the gas source is disconnected to complete the welding of the water box body and the connecting plate.

[0034] The beneficial effects of the present invention are:

[0035] The diffusion flow device of the present invention can pass the protective gas into the water box body. After the air in the water box body is fully replaced by the protective gas, the water box body is welded, which can form an effective argon gas protection environment for the parts where the side wall of the water box body and the connecting plate need to be welded, ensuring that the inside of the water box body is clean and free of foreign matter, and the weld is well fused. The locking mechanism can press the water box body and the connecting plate tightly, ensuring that the gap between the water box body and the connecting plate is more uniform during welding, avoiding the risk of water leakage due to uneven thickness of the weld and insufficient local strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the assembly structure of the present invention;

[0037] Figure 2 is a cross-sectional view of the present invention;

[0038] Figure 3 is a schematic diagram of the structure of the gas diffusion core;

[0039] Figure 4 It is a cross-sectional view of the back-tightening nut;

[0040] Figure 5 It is a schematic diagram of the structure of the locking hook;

[0041] Figure 6 It is a structural schematic diagram of the water box body and the connecting plate;

[0042] Figure 7 It is a structural schematic diagram of a stator bar assembly;

[0043] Figure 8 This is a schematic diagram of the water box body and the connecting plate after welding.

[0044] In the figure: 1-water box body; 2-connecting plate; 3-hollow strand; 4-locking mechanism; 5-gas diffusion core; 6-sealing mechanism; 11-pipe joint; 51-air outlet; 52-polyhedron; 53-anti-rotation surface; 54-positioning cylinder; 41-locking hook; 42-locking bolt; 61-tightening nut; 111-step surface; 511-straight air outlet; 512-oblique air outlet; 611-stop. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0046] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0047] like Figure 1 to Figure 5 As shown, the diffusion flow device for welding the stainless steel water box body of the steam turbine generator of this embodiment includes a locking mechanism 4 for clamping the water box body 1 and the connecting plate 2, a gas diffusion core 5 for introducing protective gas is inserted into the water box body 1, a section of the gas diffusion core 5 extending into the water box body 1 is provided with a plurality of air outlets 51, the air outlets 51 are communicated with the inner cavity of the gas diffusion core 5, a sealing mechanism 6 is connected between the gas diffusion core 5 and the water box body 1, and the protective gas introduced from the gas diffusion core 5 diffuses to the water box body 1 and then flows out along the gap between the water box body 1 and the connecting plate 2 and the hollow strand 3 passage.

[0048] The water box body 1 is aligned with the stainless steel connecting plate 2 at the end of the stator bar, and the locking mechanism 4 is used to position the water box body 1 and adjust the gap between the connecting plate 2 to meet the requirements of manual argon arc welding. The gas diffusion core 5 is inserted into the water box body 1 and sealed with the sealing mechanism 6.

[0049] According to the spatial structural characteristics of the cavity of the water box body 1 and the direction of gas escape from the cavity, different gas escape channels are designed on the gas diffusion core 5, and under the premise of avoiding the pressure difference in the cavity due to the "Bernoulli principle", the protective gas entering the cavity is layered at a low flow rate through turbulent displacement, and a turbulent flow with irregular pulsating vortex characteristics is formed through reflection of the cavity wall of the water box body 1. This turbulent protective gas under low-speed conditions forms a slight positive pressure in the cavity of the water box body 1, quickly diffuses to the entire cavity of the water box body 1, and then flows out along the gap between the water box body 1 and the connecting plate 2 and the hollow strand 3 passage, completing the air replacement in the cavity. After the air in the water box body 1 is fully replaced, the water box body 1 and the stainless steel connecting plate 2 are welded.

[0050] The diffusion flow device of the present invention can pass the protective gas into the water box body 1. After the air in the water box body 1 is fully replaced by the protective gas, the water box body 1 is welded, which can form an effective argon gas protection environment for the side wall of the water box body 1 and the part where the connecting plate 2 needs to be welded, ensuring that the inside of the water box body 1 is clean and free of foreign matter, and the weld is well fused. The locking mechanism 4 can press the water box body 1 and the connecting plate 2 tightly, ensuring that the gap between the water box body 1 and the connecting plate 2 is more uniform during welding, avoiding the risk of water leakage due to uneven thickness of the weld and insufficient local strength.

[0051] The section of the gas diffusion core 5 extending into the water box body 1 is a polyhedron 52 , and each face of the polyhedron 52 is provided with an air outlet 51 .

[0052] The air outlet holes 51 on the polyhedron 52 include a plurality of straight air outlet holes 511 parallel to the bottom surface of the water box body 1 and a plurality of oblique air outlet holes 512 obliquely upward relative to the bottom surface of the water box body 1. The plurality of straight air outlet holes 511 and the plurality of oblique air outlet holes 512 are arranged at intervals.

[0053] The air outlet hole 51 is a threaded hole.

[0054] One end of the gas diffusion core 5 away from the water box body 1 is connected with a hose.

[0055] An anti-rotation surface 53 is provided on a section of the gas diffusion core 5 extending out of the water box body 1 .

[0056] The gas diffusion core 5 is made of copper material, and the bottom is processed into a polyhedron 52. A group of straight air outlet holes 511 are arranged circumferentially on the polyhedron 52, and a group of oblique air outlet holes 512 are arranged obliquely upward at intervals. The air outlet holes 51 are connected to the inner cavity of the gas diffusion core 5.

[0057] The protective gas is evenly dispersed after entering the gas diffusion core 5, and the gas from the oblique outlet hole 512 hits the oblique wall of the water box body 1 and impacts the gas from the straight outlet hole 511. The outlet hole 51 is a threaded hole, and the air flow generates rotation, so that the protective gas stays in the water box body 1 for a longer time, fully replaces the air inside the water box body 1, and forms a protective gas environment, which saves more protective gas than the direct insertion method of the hose.

[0058] The end of the gas diffusion core 5 can be connected to a hose, and an anti-rotation surface 53 is provided in the middle section. The anti-rotation surface 53 is a plane to prevent the gas diffusion core 5 from rotating when the back-tightening nut 61 is tightened.

[0059] Furthermore, a pipe joint 11 is fixed to the water box body 1, a step surface 111 is provided in the pipe joint 11, a positioning cylinder 54 is provided on the gas diffusion core 5, the gas diffusion core 5 is inserted into the water box body 1 from the pipe joint 11, the positioning cylinder 54 overlaps the step surface 111 of the pipe joint 11, and the sealing mechanism 6 includes a back-tightening nut 61, which is threadedly connected to the pipe joint 11, and the back-tightening nut 61 presses the positioning cylinder 54.

[0060] The back-tightening nut 61 is provided with a stopper 611 , and the stopper 611 is pressed tightly against an end of the positioning cylindrical surface 54 away from the water box body 1 .

[0061] The thread of the back-tightening nut 61 matches the thread of the water box body 1. One side of the back-tightening nut 61 has a stopper 611 for locking the gas diffusion core 5 to prevent the gas diffusion core 5 from shaking and to form a seal between the gas diffusion core 5 and the pipe joint 11 of the water box body 1.

[0062] Specifically, the locking mechanism 4 includes a locking hook 41, which is a door-type frame structure. The hook body of the locking hook 41 buckles the side of the connecting plate 2 away from the water box body 1. A locking bolt 42 is threadedly connected to the locking hook 41, and the locking bolt 42 contacts the side of the water box body 1 away from the link plate. The hook body of the locking hook 41 and the locking bolt 42 press the water box body 1 and the connecting plate 2 together.

[0063] The locking hook 41 is a door-shaped frame structure with a screw hole on the top, which is matched with the locking bolt. When in use, the hook supports the water box body 1 and the connecting plate 2 to meet the welding gap requirements. The locking bolt and the locking hook 41 are used together. By tightening the locking bolt, the locking hook 41 presses against the water box body 1 to achieve temporary fixation of the water box body 1 and the connecting plate 2.

[0064] The method for using the diffusion flow device for welding a stainless steel water box body of a steam turbine generator of this embodiment comprises the following steps:

[0065] S1: First, put the back-tightening nut 61 on the gas diffusion core 5, and then connect the protective gas source hose to the tail end of the gas diffusion core 5;

[0066] S2: insert the gas diffusion core 5 into the inner hole of the water box body 1, put the back-tightening nut 61 on the pipe joint 11 of the water box body 1, and tighten the back-tightening nut 61 to form a seal between the gas diffusion core 5 and the water box body 1;

[0067] S3: Align the water box body 1 with the connecting plate 2 at the end of the stator wire rod, use the locking hook 41 and the locking bolt to position, and adjust the gap between the water box body 1 and the connecting plate 2 to meet the requirements of manual argon arc welding;

[0068] S4: Introduce protective gas into the gas diffusion core 5, wait for about 15 seconds, and after the air in the water box body 1 is fully replaced, spot weld the water box body 1 and the connecting plate 2. During the welding process, the protective gas of the water box body 1 is kept in a slightly positive pressure state, and the welds of the water box body 1 and the connecting plate 2 are welded in sequence;

[0069] S5: Loosen the locking bolt, remove the locking hook 41, and weld the remaining welds under a protective gas environment until the entire circle is fully welded, thus completing the welding work of the water box body 1 and the connecting plate 2;

[0070] S6: After welding, the protective gas is continuously introduced at a low speed for 5 minutes to cool the workpiece. When the workpiece is cooled to below 100°C, the gas source is disconnected to complete the welding of the water box body 1 and the connecting plate 2.

[0071] S7: Repeat the above operation to complete the argon arc welding of the water box body 1 and the connecting plate 2 of all stator wire bars.

[0072] The present invention is not limited to the above-mentioned optional implementation modes. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that fall within the scope defined by the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A diffusion flow device for welding a stainless steel water box of a steam turbine generator, characterized in that: The invention comprises a locking mechanism (4) for clamping a water box body (1) and a connecting plate (2); a gas diffusion core (5) for introducing protective gas is inserted into the water box body (1); a section of the gas diffusion core (5) extending into the water box body (1) is provided with a plurality of gas outlet holes (51); the gas outlet holes (51) are communicated with the inner cavity of the gas diffusion core (5); a sealing mechanism (6) is connected between the gas diffusion core (5) and the water box body (1); the protective gas introduced from the gas diffusion core (5) diffuses into the water box body (1) and then flows out along the gap between the water box body (1) and the connecting plate (2) and the passage of the hollow strand (3).

2. A diffusion flow device for welding a stainless steel water box of a steam turbine generator according to claim 1, characterized in that: The section of the gas diffusion core (5) extending into the water box body (1) is a polyhedron (52), and each face of the polyhedron (52) is provided with an air outlet hole (51).

3. A diffusion flow device for welding a stainless steel water box of a steam turbine generator according to claim 2, characterized in that: The air outlet holes (51) on the polyhedron (52) include a plurality of straight air outlet holes (511) parallel to the bottom surface of the water box body (1) and a plurality of oblique air outlet holes (512) obliquely facing upward relative to the bottom surface of the water box body (1), and the plurality of straight air outlet holes (511) and the plurality of oblique air outlet holes (512) are arranged at intervals.

4. The diffusion flow device for welding a stainless steel water box of a steam turbine generator according to claim 1, characterized in that: The air outlet hole (51) is a threaded hole.

5. The diffusion flow device for welding a stainless steel water box of a steam turbine generator according to claim 1, characterized in that: One end of the gas diffusion core (5) away from the water box body (1) is connected to a hose.

6. The diffusion flow device for welding a stainless steel water box of a steam turbine generator according to claim 1, characterized in that: An anti-rotation surface (53) is provided on a section of the gas diffusion core (5) extending out of the water box body (1).

7. The diffusion flow device for welding a stainless steel water box of a steam turbine generator according to claim 1, characterized in that: A pipe joint (11) is fixed on the water box body (1), a step surface (111) is arranged inside the pipe joint (11), a positioning cylindrical surface (54) is arranged on the gas diffusion core (5), the gas diffusion core (5) is inserted into the water box body (1) from the pipe joint (11), the positioning cylindrical surface (54) overlaps the step surface (111) of the pipe joint (11), and the sealing mechanism (6) comprises a back-tightening nut (61), the back-tightening nut (61) is threadedly connected to the pipe joint (11), and the back-tightening nut (61) presses the positioning cylindrical surface (54).

8. The diffusion flow device for welding a stainless steel water box of a steam turbine generator according to claim 7, characterized in that: The back-tightening nut (61) is provided with a stopper (611), and the stopper (611) is pressed against an end of the positioning cylindrical surface (54) away from the water box body (1).

9. The diffusion flow device for welding a stainless steel water box of a steam turbine generator according to claim 1, characterized in that: The locking mechanism (4) comprises a locking hook (41), the locking hook (41) being a door-shaped frame structure, the hook body of the locking hook (41) buckles the side of the connecting plate (2) away from the water box body (1), a locking bolt (42) is threadedly connected to the locking hook (41), the locking bolt (42) contacts the side of the water box body (1) away from the link plate, and the hook body of the locking hook (41) and the locking bolt (42) press the water box body (1) and the connecting plate (2) together.

10. A method for using a diffusion flow device for welding a stainless steel water box body of a steam turbine generator, using the diffusion flow device for welding a stainless steel water box body of a steam turbine generator according to claim 1, characterized in that: The following steps are involved: S1: first, put the back-tightening nut (61) on the gas diffusion core (5), and then connect the protective gas source hose to the tail end of the gas diffusion core (5); S2: inserting the gas diffusion core (5) into the inner hole of the water box body (1), fitting the back-tightening nut (61) onto the pipe joint (11) of the water box body (1), and tightening the back-tightening nut (61) to form a seal between the gas diffusion core (5) and the water box body (1); S3: Align the water box body (1) with the connecting plate (2) at the end of the stator wire rod, use the locking hook (41) and the locking bolt to position, and adjust the gap between the water box body (1) and the connecting plate (2) to meet the requirements of manual argon arc welding; S4: introducing a protective gas into the gas diffusion core (5), and after the air in the water box body (1) is fully replaced, spot welding the water box body (1) and the connecting plate (2), wherein the protective gas in the water box body (1) is always maintained in a slightly positive pressure state during the welding process, and the welds of the water box body (1) and the connecting plate (2) are welded in sequence; S5: Loosen the locking bolt, remove the locking hook (41), and weld the remaining weld under a protective gas environment until the entire circle is fully welded; S6: After welding, the protective gas is continuously introduced at a low speed to cool the workpiece. When the workpiece is cooled to below 100° C., the gas source is disconnected, and the welding of the water box body (1) and the connecting plate (2) is completed.

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