Production method for preventing cavitation by surfacing martensitic stainless steel on the flow surface of fixed guide vanes

Abstract

The present invention provides a production method for preventing cavitation by surfacing martensitic stainless steel on the flow surface of a fixed guide vane, comprising: reserving a surfacing surface in the cavitation-prone area of ​​the flow surface of the fixed guide vane, welding the fixed guide vane and the upper ring plate and the lower ring plate of the seat ring to form an integral part; wherein an austenitic stainless steel transition layer is surfacing on the surfacing surface, and a martensitic stainless steel corrosion-resistant layer is surfacing on the surface of the austenitic stainless steel transition layer. The present invention uses low-alloy high-strength structural steel to make the fixed guide vane body, reserves a surfacing surface in the erosion-prone area of ​​the flow surface, and surfacing martensitic stainless steel on the fixed guide vane body at two surfacing times: surfacing the fixed guide vane alone first and then assembling and surfacing with the upper and lower ring plates, and surfacing the fixed guide vane after assembling and surfacing with the upper and lower ring plates. Since the martensitic stainless steel wear-resistant layer is formed on the flow surface of the fixed guide vane, the cavitation degree of the flow surface of the fixed guide vane can be effectively alleviated, the maintenance cycle can be shortened, the maintenance cost can be reduced, and the economic benefits of the industrial production of water pump turbines can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of fixed guide vane production methods, and specifically relates to a production method for surfacing martensitic stainless steel on the flow-through surface of a fixed guide vane to prevent cavitation. Background Art

[0002] During long-term operation, the flow-through components of pump-turbines are subjected to the combined effects of erosion, abrasion and electrochemical corrosion, which can easily lead to material damage and affect the power generation and efficiency of the pump-turbines.

[0003] The fixed guide vane is one of the common flow components of the pump turbine. During the long-term operation of the unit, a large number of cavitation defects will appear on the flow surface of the fixed guide vane. Summary of the invention

[0004] In view of the defects in the prior art, the present invention provides a production method for surfacing martensitic stainless steel on the flow surface of a fixed guide vane to prevent cavitation, which can effectively solve the above problems.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The present invention provides a production method for surfacing martensitic stainless steel on the flow surface of a fixed guide vane to prevent cavitation, comprising the following steps:

[0007] Step S1, using a low alloy high strength structural steel plate to cold press form to manufacture a fixed guide vane (1);

[0008] Step S2, machining the fixed guide vane (1), reserving a surfacing surface (2) in a cavitation-prone area of ​​the guide vane flow surface of the fixed guide vane (1), wherein the area of ​​the surfacing surface (2) forms a groove relative to the main body area of ​​the fixed guide vane (1);

[0009] Step S3, the fixed guide vane (1) and the seat ring upper ring plate (5) and the seat ring lower ring plate (6) are welded to form an integral part; wherein an austenitic stainless steel transition layer is welded on the weld surface (2), and a martensitic stainless steel corrosion-resistant layer is welded on the surface of the austenitic stainless steel transition layer, so that the weld surface formed after the welding and the main body area of ​​the fixed guide vane (1) form a smooth surface.

[0010] Preferably, it is characterized in that step S3 specifically comprises:

[0011] Step S3.1, performing single-piece surfacing welding on the fixed guide vane (1), the method being:

[0012] The edge groove position of the surfacing surface (2) of the fixed guide vane (1) is the position in contact with the seat ring upper ring plate (5) and the seat ring lower ring plate (6), and except for the edge groove position, a first austenitic stainless steel transition layer (3-1) is surfacing-welded on the surfacing surface (2) of the fixed guide vane (1), and a first martensitic stainless steel corrosion-resistant layer (4-1) is surfacing-welded on the surface of the first austenitic stainless steel transition layer (3-1), so as to form a rough fixed guide vane;

[0013] Performing post-weld heat treatment on the weld layer surface of the rough fixed guide vane to obtain a fixed guide vane (1) after heat treatment;

[0014] Step S3.2, assembling the heat-treated fixed guide vane (1) and the seat ring upper ring plate (5) and the seat ring lower ring plate (6);

[0015] The contact area between the heat-treated fixed guide vane (1) and the seat ring upper ring plate (5) and the seat ring lower ring plate (6) includes the edge groove area of ​​the cladding surface (2) and other edge contact area;

[0016] In the region of the edge groove position of the contacting cladding surface (2), a low-alloy high-strength welding material (8) is first used to weld to a level with the bottom surface of the first austenitic stainless steel transition layer (3-1), so as to form a groove weld (7); a second austenitic stainless steel transition layer (3-2) is clad on the surface of the groove weld (7), so that the second austenitic stainless steel transition layer (3-2) and the first austenitic stainless steel transition layer (3-1) are connected and have the same thickness; a second martensitic stainless steel corrosion-resistant layer (4-2) is clad on the surface of the second austenitic stainless steel transition layer (3-2), so that the second martensitic stainless steel corrosion-resistant layer (4-2) and the first martensitic stainless steel corrosion-resistant layer (4-1) are connected and have the same thickness;

[0017] Processing the surface of the second martensitic stainless steel corrosion-resistant layer (4-2) and performing stress relief annealing;

[0018] In the other edge contact position areas, welding is performed using a low alloy high strength welding material (8);

[0019] Thus, the fixed guide vane (1), the seat ring upper ring plate (5), and the seat ring lower ring plate (6) are welded to form an integral part.

[0020] Preferably, it is characterized in that the thickness of the first austenitic stainless steel transition layer (3-1) is 1-10 mm; the thickness of the first martensitic stainless steel corrosion-resistant layer (4-1) is 1-20 mm.

[0021] Preferably, step S3 specifically comprises:

[0022] Step S3A, assembling the fixed guide vane (1) with the surfacing surface (2) reserved, the seat ring upper ring plate (5), and the seat ring lower ring plate (6) to form an integral part;

[0023] Step S3B, performing overall surfacing welding on the integral part, the method is as follows:

[0024] The fixed guide vane (1) with a reserved surfacing surface (2) and the area to be surfacing between the seat ring upper ring plate (5) and the seat ring lower ring plate (6) include three parts: the first part is the main area of ​​the surfacing surface (2) of the fixed guide vane (1); the second part is the edge groove position of the surfacing surface (2) of the fixed guide vane (1), that is, the position where the surfacing surface (2) of the fixed guide vane (1) contacts the seat ring upper ring plate (5) and the seat ring lower ring plate (6); the third part is the non-edge groove position of the fixed guide vane (1) and the position where the seat ring upper ring plate (5) and the seat ring lower ring plate (6) contact, which is called other edge contact position area;

[0025] At the edge groove position, firstly, a low-alloy high-strength welding material (8) is used to weld to the surface of the main body area flush with the surfacing surface (2) of the fixed guide vane (1), so as to form a groove weld (7);

[0026] On the one hand, low-alloy high-strength welding materials (8) are used for welding in other edge contact position areas; on the other hand, a first austenitic stainless steel transition layer (3-1) is simultaneously welded on the surface of the groove weld (7) and the surface of the main area of ​​the weld surface (2) of the fixed guide vane (1), and a first martensitic stainless steel corrosion-resistant layer (4-1) is welded on the surface of the first austenitic stainless steel transition layer (3-1);

[0027] The surface of the first martensitic stainless steel corrosion-resistant layer (4-1) is subjected to post-weld heat treatment to obtain a final product.

[0028] Preferably, the thickness of the first austenitic stainless steel transition layer (3-1) is 1-10 mm; the thickness of the first martensitic stainless steel corrosion-resistant layer (4-1) is 1-20 mm.

[0029] The production method of surfacing martensitic stainless steel on the flow surface of a fixed guide vane to prevent cavitation provided by the present invention has the following advantages:

[0030] The present invention uses low-alloy high-strength structural steel to make the fixed guide vane body, reserves a surfacing surface in the easily corroded area of ​​the flow surface, and surfacing martensitic stainless steel is welded to the fixed guide vane body at two surfacing times: the fixed guide vane is first surfacing welded alone and then assembled with the upper and lower ring plates, and the fixed guide vane is assembled with the upper and lower ring plates and then surfacing welded. Since the martensitic stainless steel wear-resistant layer is formed on the flow surface of the fixed guide vane, the cavitation degree of the flow surface of the fixed guide vane can be effectively alleviated, the maintenance cycle can be shortened, the maintenance cost can be reduced, and the economic benefits of the industrial production of water pump turbines can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic structural diagram of a fixed guide vane with a reserved surfacing surface of a water pump turbine seat ring provided by the present invention;

[0032] Figure 2 The schematic diagram of the fixed guide vane surfacing welding that first participates in the single-piece surfacing welding is shown;

[0033] Figure 3 This is a schematic diagram of the fixed guide vane and the upper and lower ring plates that are first subjected to single-piece cladding and then assembled for cladding;

[0034] Figure 4 It is a schematic diagram of the structure after the fixed guide vane and the upper and lower ring plates are assembled without single-piece surfacing welding;

[0035] Figure 5 A cross-sectional view of the integral part formed by the final cladding in the cladding area;

[0036] Figure 6 for Figure 5 Partial magnification;

[0037] Figure 7 A top view of the integral part formed by the final cladding;

[0038] Figure 8 for Figure 7 Partial enlarged image. DETAILED DESCRIPTION

[0039] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] The present invention provides a production method for preventing cavitation by cladding martensitic stainless steel on the flow surface of a fixed guide vane. Low-alloy high-strength structural steel is used as the material of the fixed guide vane. An austenitic stainless steel transition layer and a martensitic stainless steel corrosion-resistant layer are sequentially clad in the cavitation-prone area of ​​the flow surface of the fixed guide vane by cladding. This can effectively alleviate the cavitation degree of the flow surface of the fixed guide vane, shorten the maintenance cycle, reduce maintenance costs, and improve the economic benefits of the industrial production of water pumps and turbines.

[0041] The present invention provides a production method for surfacing martensitic stainless steel on the flow surface of a fixed guide vane to prevent cavitation, comprising the following steps:

[0042] Step S1, using low alloy high strength structural steel plate to cold press, process and grind to obtain a fixed guide vane 1;

[0043] Step S2, processing the fixed guide vane 1, reserving a surfacing surface 2 in the cavitation-prone area of ​​the guide vane flow surface of the fixed guide vane 1, and forming a groove body in the area of ​​the surfacing surface 2 relative to the main area of ​​the fixed guide vane 1, forming Figure 1 The structure shown;

[0044] Step S3, the fixed guide vane 1 and the seat ring upper ring plate 5 and the seat ring lower ring plate 6 are welded to form an integral part; wherein, an austenitic stainless steel transition layer is welded on the weld surface 2, and a martensitic stainless steel corrosion-resistant layer is welded on the surface of the austenitic stainless steel transition layer, so that the weld surface formed after the weld and the main area of ​​the fixed guide vane 1 form a smooth surface.

[0045] In the present invention, the austenitic stainless steel transition layer can be a 309 type austenitic stainless steel transition layer with a thickness of 1-10 mm; the martensitic stainless steel corrosion resistant layer can be a 410NiMo type martensitic stainless steel corrosion resistant layer with a thickness of 1-20 mm. After surfacing welding, the martensitic stainless steel corrosion resistant layer can be further subjected to stress relief annealing, and the martensitic stainless steel corrosion resistant layer can be processed and subjected to surface penetration testing.

[0046] When performing step S3, according to the timing of surfacing welding, there are two methods: first surfacing welding of the fixed guide vane as a single piece and then surfacing welding after assembling with the upper and lower ring plates, and surfacing welding of the fixed guide vane as a whole after assembling with the upper and lower ring plates. The following are two introductions:

[0047] The first method: The fixed guide vane is first welded as a single piece and then assembled with the upper and lower ring plates and then welded

[0048] Step S3 is specifically as follows:

[0049] Step S3.1, performing single-piece surfacing welding on the fixed guide vane 1, the method is as follows:

[0050] like Figure 2As shown, the edge groove position of the surfacing surface 2 of the fixed guide vane 1 is the position in contact with the seat ring upper ring plate 5 and the seat ring lower ring plate 6. Except for the edge groove position, the surfacing surface 2 of the fixed guide vane 1 is welded with an austenitic stainless steel welding wire to weld a 1-10 mm first austenitic stainless steel transition layer 3-1. After the first austenitic stainless steel transition layer 3-1 is welded, a martensitic stainless steel welding wire is used to weld a 1-20 mm first martensitic stainless steel corrosion resistant layer 4-1 on the surface of the first austenitic stainless steel transition layer 3-1 to ensure that the total thickness of the processed surfacing layer is consistent with the original fixed guide vane thickness, so as to form a rough fixed guide vane.

[0051] Performing post-weld heat treatment on the weld layer surface of the rough fixed guide vane for processing, thereby obtaining a fixed guide vane 1 after heat treatment;

[0052] Step S3.2, such as Figure 3 As shown, the heat-treated fixed guide vane 1 and the seat ring upper ring plate 5 and the seat ring lower ring plate 6 are assembled;

[0053] The contact area between the heat-treated fixed guide vane 1 and the seat ring upper plate 5 and the seat ring lower plate 6 includes the edge groove area of ​​the cladding surface 2 and other edge contact area;

[0054] In the area of ​​the edge groove position of the contacting cladding surface 2, firstly, a low-alloy high-strength welding material 8 is used to weld to be flush with the bottom surface of the first austenitic stainless steel transition layer 3-1 to form a groove weld 7; the fixed guide vane 1 and the seat ring upper ring plate 5 and the seat ring lower ring plate 6 are groove welded;

[0055] Then, a 1-10 mm second austenitic stainless steel transition layer 3-2 is built-up on the surface of the groove weld 7, so that the second austenitic stainless steel transition layer 3-2 is connected to the first austenitic stainless steel transition layer 3-1 and has the same thickness; after the second austenitic stainless steel transition layer 3-2 is welded, a 1-20 mm second martensitic stainless steel corrosion-resistant layer 4-2 is built-up on the surface of the second austenitic stainless steel transition layer 3-2 using a martensitic stainless steel welding wire, so that the second martensitic stainless steel corrosion-resistant layer 4-2 is connected to the first martensitic stainless steel corrosion-resistant layer 4-1 and has the same thickness;

[0056] Processing the surface of the second martensitic stainless steel corrosion resistant layer 4-2 and performing stress relief annealing;

[0057] In other edge contact areas, low alloy high strength welding material 8 is used for welding;

[0058] Thus, the fixed guide vane 1 and the seat ring upper ring plate 5 and the seat ring lower ring plate 6 are welded to form an integral part.

[0059] As a specific implementation, the thickness of the first austenitic stainless steel transition layer 3-1 is 1-10 mm; the thickness of the first martensitic stainless steel corrosion-resistant layer 4-1 is 1-20 mm.

[0060] The second method: integral surfacing after the fixed guide vane and upper and lower ring plates are assembled

[0061] Step S3 is specifically as follows:

[0062] Step S3A, such as Figure 4 As shown, the fixed guide vane 1 with the surfacing surface 2 reserved and the seat ring upper ring plate 5 and the seat ring lower ring plate 6 are assembled to form an integral part;

[0063] Step S3B, performing overall surfacing welding on the integral part, the method is as follows:

[0064] The fixed guide vane 1 with the surfacing surface 2 reserved and the area to be surfacing between the seat ring upper ring plate 5 and the seat ring lower ring plate 6 includes three parts: the first part is the main area of ​​the surfacing surface 2 of the fixed guide vane 1; the second part is the edge groove position of the surfacing surface 2 of the fixed guide vane 1, that is, the position where the surfacing surface 2 of the fixed guide vane 1 contacts with the seat ring upper ring plate 5 and the seat ring lower ring plate 6; the third part is the non-edge groove position of the fixed guide vane 1 and the position where the seat ring upper ring plate 5 and the seat ring lower ring plate 6 contact, which is called other edge contact position area;

[0065] At the edge groove position, firstly, a low-alloy high-strength welding material 8 is used to weld to the surface of the main area of ​​the surfacing surface 2 of the fixed guide vane 1 to be flush with the surface to form a groove weld 7;

[0066] On the one hand, low alloy high strength welding material 8 is used for welding in other edge contact position areas; on the other hand, a 1-10 mm first austenitic stainless steel transition layer 3-1 is simultaneously welded on the surface of the groove weld 7 and the surface of the main area of ​​the weld surface 2 of the fixed guide vane 1, and a 1-20 mm first martensitic stainless steel corrosion resistant layer 4-1 is welded on the surface of the first austenitic stainless steel transition layer 3-1;

[0067] The surface of the first martensitic stainless steel corrosion-resistant layer 4-1 is subjected to post-weld heat treatment to obtain a final product.

[0068] As a specific implementation, the thickness of the first austenitic stainless steel transition layer 3-1 is 1-10 mm; the thickness of the first martensitic stainless steel corrosion-resistant layer 4-1 is 1-20 mm.

[0069] In the present invention, both the first welding method and the second welding method need to be subjected to nondestructive testing after welding to determine whether there are defects. The cross-sectional views of the integral parts formed after welding are as follows: Figure 5 and Figure 6 As shown, the top view is as Figure 7 and Figure 8 shown.

[0070] The present invention provides a production method for preventing cavitation by cladding martensitic stainless steel on the flow surface of a fixed guide vane. The fixed guide vane body is made of low-alloy high-strength structural steel, and martensitic stainless steel is claddinged on the surface of the fixed guide vane body made of the low-alloy high-strength structural steel. After cladding, a martensitic stainless steel wear-resistant layer exists in the corrosion-prone area of ​​the flow surface of the fixed guide vane, which has excellent wear resistance and corrosion resistance. Therefore, after welding, the wear resistance and corrosion resistance of the flow surface of the fixed guide vane are improved, the service life is increased, and the maintenance cycle is shortened.

[0071] Two embodiments are described below:

[0072] The surfacing welding of the erosion-prone area of ​​the flow surface of the fixed guide vane can be divided into the surfacing welding of the fixed guide vane as a single piece and then assembled with the upper and lower ring plates, and the surfacing welding of the fixed guide vane as a whole after the fixed guide vane and the upper and lower ring plates are assembled. Example 1 is a method of surfacing the fixed guide vane as a single piece and then assembled with the upper and lower ring plates. Example 2 is an integral surfacing welding after the fixed guide vane and the upper and lower ring plates are assembled.

[0073] Example 1

[0074] like Figure 1 As shown, the main body of the pump turbine seat ring fixed guide vane 1 is manufactured by cold pressing low-alloy high-strength structural steel plate, and the cavitation-prone area of ​​the guide vane flow surface of the fixed guide vane 1 is processed and polished to form a surfacing surface 2;

[0075] like Figure 2 As shown, it is a single-piece surfacing of a fixed guide vane, and a 309-type austenitic stainless steel transition layer 3 with a thickness of 1-10 mm is surfacing on the surfacing surface 2 of the fixed guide vane 1; after the transition layer is welded, a 410NiMo-type martensitic stainless steel corrosion-resistant layer 4 with a thickness of 1-20 mm is surfacing on its surface; in the case of single-piece surfacing, the groove of the surfacing surface 2 is not welded; in order to facilitate the subsequent processing of the martensitic stainless steel corrosion-resistant layer 4, the fixed guide vane 1 involved in the single-piece surfacing can be subjected to a post-weld heat treatment after the surfacing layer is welded;

[0076] like Figure 3As shown, the fixed guide vane 1 involved in the single-piece surfacing is assembled with the upper ring plate 5 of the seat ring and the lower ring plate 6 of the seat ring; the groove weld 7 at the groove position of the fixed guide vane 1 and the upper and lower ring plates is welded with low-alloy high-strength welding material 8. The non-surfacing area needs to be welded fully. For the groove where the surfacing surface 2 is located, first use low-alloy high-strength welding material 8 to fill the surfacing layer, then use 309 type austenitic stainless steel welding material to surfacing to form the second austenitic stainless steel transition layer 3-2, and finally use 410NiMo type martensitic stainless steel welding material to form the second martensitic stainless steel corrosion-resistant layer 4-2; the second martensitic stainless steel corrosion-resistant layer 4-2 of the fixed guide vane 1 should be stress-relieved and annealed after surfacing, and the second martensitic stainless steel corrosion-resistant layer 4-2 should be processed and surface penetration flaw detection should be performed.

[0077] Example 2

[0078] like Figure 4 As shown, the surfacing welding of the fixed guide vane 1 and the upper ring plate 5 and the lower ring plate 6 of the seat ring after assembly, the non-groove position welds of the fixed guide vane 1 and the upper and lower ring plates are welded with low-alloy high-strength welding materials 8, and the non-surfacing parts need to be welded fully. For the groove weld 7 where the surfacing surface 2 is located, first use low-alloy high-strength welding materials 8 to fill the surfacing layer, then use 309 austenitic stainless steel welding materials to surfacing to form an austenitic stainless steel transition layer, and finally use 410NiMo martensitic stainless steel welding materials to form a martensitic stainless steel corrosion-resistant layer; the martensitic stainless steel corrosion-resistant layer of the fixed guide vane 1 should be stress-relieved and annealed after surfacing, and the martensitic stainless steel corrosion-resistant layer should be processed and subjected to surface penetration flaw detection;

[0079] like Figure 5 and Figure 6 As shown, the inside of the groove weld 7 between the fixed guide vane 1 and the seat ring upper ring plate 5 and the seat ring lower ring plate 6 is welded and filled with low-alloy high-strength welding material 8, the transition layer is made of 309 type austenitic stainless steel welding material, and the surface layer is made of 410NiMo type martensitic stainless steel welding material.

[0080] The present invention uses low-alloy high-strength structural steel to make the fixed guide vane body, reserves a surfacing surface in the easily corroded area of ​​the flow surface, and surfacing martensitic stainless steel is welded to the fixed guide vane body at two surfacing times: the fixed guide vane is first surfacing welded alone and then assembled with the upper and lower ring plates, and the fixed guide vane is assembled with the upper and lower ring plates and then surfacing welded. Since the martensitic stainless steel wear-resistant layer is formed on the flow surface of the fixed guide vane, the cavitation degree of the flow surface of the fixed guide vane can be effectively alleviated, the maintenance cycle can be shortened, the maintenance cost can be reduced, and the economic benefits of the industrial production of water pump turbines can be improved.

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A production method for surfacing martensitic stainless steel on the flow surface of a fixed guide vane to prevent cavitation, characterized in that: The following steps are involved: Step S1, using a low alloy high strength structural steel plate to cold press form to manufacture a fixed guide vane (1); Step S2, machining the fixed guide vane (1), reserving a surfacing surface (2) in a cavitation-prone area of ​​the guide vane flow surface of the fixed guide vane (1), wherein the area of ​​the surfacing surface (2) forms a groove relative to the main body area of ​​the fixed guide vane (1); Step S3, the fixed guide vane (1) and the seat ring upper ring plate (5) and the seat ring lower ring plate (6) are welded to form an integral part; wherein an austenitic stainless steel transition layer is welded on the weld surface (2), and a martensitic stainless steel corrosion resistant layer is welded on the surface of the austenitic stainless steel transition layer, so that the weld surface formed after the weld and the main body area of ​​the fixed guide vane (1) form a smooth surface; Step S3 is specifically as follows: Step S3.1, performing single-piece surfacing welding on the fixed guide vane (1), the method being: The edge groove position of the surfacing surface (2) of the fixed guide vane (1) is the position in contact with the seat ring upper ring plate (5) and the seat ring lower ring plate (6), and except for the edge groove position, a first austenitic stainless steel transition layer (3-1) is surfacing-welded on the surfacing surface (2) of the fixed guide vane (1), and a first martensitic stainless steel corrosion-resistant layer (4-1) is surfacing-welded on the surface of the first austenitic stainless steel transition layer (3-1), so as to form a rough fixed guide vane; Performing post-weld heat treatment on the weld layer surface of the rough fixed guide vane to obtain a fixed guide vane (1) after heat treatment; Step S3.2, assembling the heat-treated fixed guide vane (1) and the seat ring upper ring plate (5) and the seat ring lower ring plate (6); The contact area between the heat-treated fixed guide vane (1) and the seat ring upper ring plate (5) and the seat ring lower ring plate (6) includes the edge groove area of ​​the cladding surface (2) and other edge contact area; In the region of the edge groove position of the contacting cladding surface (2), a low-alloy high-strength welding material (8) is first used to weld to a level with the bottom surface of the first austenitic stainless steel transition layer (3-1), so as to form a groove weld (7); a second austenitic stainless steel transition layer (3-2) is clad on the surface of the groove weld (7), so that the second austenitic stainless steel transition layer (3-2) and the first austenitic stainless steel transition layer (3-1) are connected and have the same thickness; a second martensitic stainless steel corrosion-resistant layer (4-2) is clad on the surface of the second austenitic stainless steel transition layer (3-2), so that the second martensitic stainless steel corrosion-resistant layer (4-2) and the first martensitic stainless steel corrosion-resistant layer (4-1) are connected and have the same thickness; Processing the surface of the second martensitic stainless steel corrosion-resistant layer (4-2) and performing stress relief annealing; In the other edge contact position areas, welding is performed using a low alloy high strength welding material (8); Thus, the fixed guide vane (1), the seat ring upper ring plate (5), and the seat ring lower ring plate (6) are welded to form an integral part.

2. The method for preventing cavitation by surfacing martensitic stainless steel on the flow surface of a fixed guide vane according to claim 1, characterized in that: The thickness of the first austenitic stainless steel transition layer (3-1) is 1-10 mm; the thickness of the first martensitic stainless steel corrosion-resistant layer (4-1) is 1-20 mm.

Images