WO2024055509A1

WO2024055509A1 - Insertion piece and method for repairing gap between shrouds of titanium alloy blades of steam turbine

Info

Publication number: WO2024055509A1
Application number: PCT/CN2023/076901
Authority: WO
Inventors: 马义良; 张勇; 李宇峰; 张邵勋; 关淳; 王庆生; 初世明; 刘洋; 郭魁俊; 梁天赋; 田硕; 潘劭平; 赵洪羽; 徐林峰
Original assignee: 哈电发电设备国家工程研究中心有限公司; 哈尔滨汽轮机厂有限责任公司
Priority date: 2022-09-14
Filing date: 2023-02-17
Publication date: 2024-03-21
Also published as: CN115502654B; CN115502654A

Abstract

An insertion piece for repairing a gap between shrouds of titanium alloy blades of a steam turbine, the insertion piece comprising a first insertion piece structure (61) and a second insertion piece structure (62), wherein one end of the second insertion piece structure (62) is perpendicular to the first insertion piece structure (61); the second insertion piece structure is enclosed by two arc-face structures having the same radius and a planar structure, the circle centers of the two arc-face structures being on the same horizontal line and having a certain distance therebetween; and when the planar structure is in a horizontal state, an outer circular-arc face of the first insertion piece structure (61) is connected to an arc-face structure on an inner side of the second insertion piece structure (62), and a lower edge and a left edge of the first insertion piece structure are correspondingly aligned with a lower edge and a left edge of the second insertion piece structure. By means of repairing a gap between shrouds of blades, a gap between shrouds of titanium alloy blades is controlled within a safety design range, thereby solving the problem of contact stiffness being unstable due to the gap between the shrouds of the titanium alloy blades exceeding a standard, and making the blades operate safely. Further provided is a method for repairing a gap between shrouds of titanium alloy blades of a steam turbine.

Description

A steam turbine titanium alloy blade shroud gap repair insert and gap repair method

Technical field

The invention relates to a blade shroud gap repair insert and a gap repair method, belonging to the technical field of steam turbine blades.

Background technique

Since the connected steam turbine blades are arranged in a circular array, a stable contact stiffness must be formed between the shrouds of the blades at the operating speed. When the gap between the blade shrouds caused by processing, assembly, operation, etc. is found during the maintenance process, When the gap exceeds the standard, it needs to be dealt with in time, because the excessive gap destroys the entire circle linking characteristics of the blade, the contact of the blade shroud is in an unstable state, and the continued operation of the blade may pose safety risks.

Therefore, there is an urgent need to propose a steam turbine titanium alloy blade shroud gap repair insert and a gap repair method to solve the above technical problems.

Contents of the invention

The research and development of this invention solves the problem of blade operation safety caused by the excessive clearance of the titanium alloy blade shrouds of current steam turbines. The following provides a brief summary of the invention in order to provide a basic understanding of certain aspects of the invention. It should be understood that this summary is not an exhaustive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention.

Technical solution of the present invention:

A steam turbine titanium alloy blade shroud gap repair insert includes a first insert structure and a second insert structure. One end of the second insert structure is arranged perpendicularly to the first insert structure. The second insert structure consists of two It is composed of an arc surface structure and a planar structure with the same radius. The centers of the two arc surface structures are on the same horizontal line and have a certain distance. The planar structure is in a horizontal state. The outer arc surface of the first insert structure is in contact with the second arc surface structure. The arc surface structures on the inner sides of the two insert structures are connected, and the lower edges and left edges of the two insert structures are set to each other.

Preferably: the height of the second insert structure is H1, the height of the first insert structure is H2, H1>H2, and the radius of the inner arc surface of the first insert structure is smaller than the arc surface inside the second insert structure. For the radius of the structure, the arc surface structure inside the first insert structure and the second insert structure are coaxially arranged. The arc angle of the first insert structure is α, and the arc angle of the second insert structure is greater than α.

Preferably: the outer arc side of the second insert structure is chamfered.

A method for repairing the shroud gap of a steam turbine titanium alloy blade: the insert includes a first insert structure and an insert structure arranged perpendicularly to the second insert structure, and includes the following steps:

Step 1: Gap grinding before repair;

Step 2: Insert selection;

Step 3: Insert patch repair;

Step 4: Insert welding;

Step 5: Non-destructive testing after repair;

Step 6: Grind the repaired gap;

Step 7: Non-destructive testing after grinding.

Preferably: the blade shroud includes a first shroud structure and a second shroud structure, the first shroud structure is connected to the second shroud structure, and there is wear between the working surfaces of the first shroud structure and the second shroud structure. Create a gap.

Preferred: include the following steps:

Step 1: Grind the working surface of the first shroud structure and the second shroud structure before repair, grind the gap into a shape corresponding to the insert, and grind the chamfer on the working surface of the first shroud structure. In the welding area, the gap after grinding requires a smooth transition of the wear position, and cleaning with alcohol to clean the surface;

Step 2: Select the inserts. The inserts are designed with different thickness specifications. According to the maximum gap on one side of the gap after grinding, select the second insert structure with appropriate thickness;

Step 3: Repair the insert, clamp the insert in a bench vise, polish the edges and corners of the insert according to the gap contour, so that the repaired insert can adapt to the ground gap, and insert the second insert structure of the insert into In the gap, the surface of the first insert structure is in contact with the second shroud structure and marked with a marking line to check the tightness of the contact between the insert structure and the back side of the second shroud structure;

Step 4: Weld the inserts, mechanically remove the oxide layer on the turbine blades and the parts to be welded on the inserts, and use acetone or alcohol to wipe the inserts, the parts of the turbine blades to be welded and the areas near the welds; assemble the inserts into the gaps in and fixed by spot welding;

Step 5: Non-destructive inspection. After the welding is completed, first conduct a visual inspection. There should be no undercuts, pores, or crack defects in the first welding area and the second welding area; the surface color of the weld should be silvery white, light yellow, or golden yellow;

Step 6: Grind the blade shroud after welding the inserts, clean the first welding area and the second welding area, and grind the excess welding meat to ensure that the end of the blade shroud is flush with the blade shroud surface and must not be lowered. on the blade shroud surface;

Step 7: Non-destructive testing. Conduct a visual inspection with a 10x magnifying glass on the surface of the first welding area and the second welding area again. There should be no undercuts, pores, or crack defects.

Preferable: In step two, the thickness of the second insert structure should be selected to be 0.3mm larger than the measurement gap.

Preferable: In step three, use red red powder to check the fit between the insert and the working surface of the first and second shroud structures. The contact area should be greater than 75%.

Preferred: In step four, for welding the insert and the second shroud structure, first mechanically remove the oxide layer on the second shroud structure and the parts to be welded on the insert, and wipe the insert and the second shroud with acetone or alcohol. Assemble the inserts at the parts to be welded with the structure and near the welds, and perform spot welding to fix them. Check the welding equipment and argon gas bottle pressure before welding, and adjust the argon protection equipment according to the welding position so that it can Without affecting the welding operation, the heat-affected zone of the weld, back and gap should be well protected; the welding material should be TA1 welding wire with a diameter of 1.6mm. The welding wire is not allowed to have cracks or interlayers. Wipe it clean with acetone or alcohol before use. Welding uses tungsten argon arc welding, the current is 40-75A, the argon gas flow is 10-15L/min, the interlayer temperature is less than 60°C, and high-frequency arc starting is used.

Preferred: The welding equipment adopts argon arc welding machine.

The invention has the following beneficial effects:

1. By repairing the gap of the blade shroud, the present invention controls the titanium alloy blade shroud gap within the safe design range, solves the problem of excessive titanium alloy blade shroud gap and unstable contact stiffness, and ensures safe operation of the blades;

2. The present invention realizes the shroud gap filling of titanium alloy blades by using insert welding and repair of titanium alloy materials;

3. The present invention extends the service life of the blades and reduces the maintenance cost of the steam turbine unit. The welding repair method is simple to operate, has strong adaptability and versatility, and can be widely used to repair excessive gaps in the shrouds of titanium alloy blades of steam turbines.

Description of drawings

Figure 1 is a three-dimensional view of a steam turbine titanium alloy blade shroud gap repair insert;

Figure 2 is a top view of a steam turbine titanium alloy blade shroud gap repair insert;

Figure 3 is a front view of a steam turbine titanium alloy blade shroud gap repair insert;

Figure 4 is a flow chart of a method for repairing the shroud gap of a steam turbine titanium alloy blade;

Figure 5 is a perspective view of the blade shroud;

Figure 6 is a gap comparison chart under different states;

Figure 7 is a schematic diagram of the installation position of the insert;

Figure 8 is a partial schematic diagram of the installation position of the insert;

Figure 9 is a top view of the insert installation position;

FIG. 10 is a cross-sectional view along line A-A in FIG. 9 .

In the picture: 1-First shroud structure, 2-Second shroud structure, 3-Normal blade shroud gap, 4-Gap, 5-Repaired blade shroud gap, 6-Insert piece, 61-No. One insert structure, 62-the second insert structure, 7-the first welding area, 8-the second welding area.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is described below through the specific embodiments shown in the drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. Furthermore, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily confusing the concepts of the present invention.

In the present invention, unless otherwise clearly stated and limited, the terms "installation", "connection", "connection", "fixing" and other terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrated; 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 an internal connection between two elements or an interaction between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Specific Embodiment 1: This embodiment will be described with reference to Figures 1-3. A steam turbine titanium alloy blade shroud gap repair insert in this embodiment includes a first insert structure 61 and a second insert structure 62. The second insert One end of the sheet structure 62 is arranged perpendicularly to the first insert structure 61; the second insert structure 62 is composed of two arc surface structures and a planar structure with the same radius, and the centers of the two arcs are on the same horizontal line and at a distance of For D, the planar structure is in a horizontal state, the outer arc surface of the first insert structure 61 is connected to the arc surface structure inside the second insert structure 62, and the lower edges and left edges of the two are set opposite each other;

The height of the second insert structure 62 is H1, the height of the first insert structure 61 is H2, H1>H2, and the radius of the inner arc surface of the first insert structure 61 is smaller than the inner arc of the second insert structure 62 The radius of the surface structure, the arc surface structure inside the first insert structure 61 and the second insert structure 62 is coaxially arranged, the arc angle of the first insert structure 61 is α, and the arc angle of the second insert structure 62 Degree is greater than α;

The outer arc side of the second insert structure 62 is processed with a chamfer 63, and the chamfer 63 is 0.2×45°; by adjusting the values of the center distance D and R12, its shape can be changed to adapt to different gaps 4.

Specific embodiment 2: This embodiment is described in conjunction with Figures 1-10. This embodiment is a method for repairing the gap between the titanium alloy blade shroud of a steam turbine, comprising a first insert structure 61 and a second insert structure 62. The second insert structure 62 has a The end is vertically arranged with the first inserting sheet structure 61, and the first inserting sheet structure 61 and the second inserting sheet structure 62 are integrally formed;

The second insert structure 62 is composed of two arc surface structures with a radius of R12 and a planar structure. The centers of the two arcs are on the same horizontal line and the distance is D. The planar structure is in a horizontal state, and the first insert structure is in a horizontal state. The outer arc surface of the structure 61 is connected to the arc surface structure inside the second insert structure 62, and the lower edge and left edge of the two are set to each other. The radius of the inner arc surface of the first insert structure 61 is R9;

H1 is 13mm, H2 is 2mm, α is 30°, the outer arc side of the second insert structure 62 is processed with a chamfer 63, and the chamfer 63 is 0.2×45°;

A steam turbine titanium alloy blade shroud gap repair insert is an insert 6. The insert 6 includes a second insert structure 62 and an insert structure 61 arranged perpendicularly to the second insert structure 62.

The blade is connected to the blade shroud. The blade shroud includes a first shroud structure 1 and a second shroud structure 2. The first shroud structure 1 is connected to the second shroud structure 2. The first shroud structure 1 is connected to the second shroud structure 2. The wear between the working surfaces of the two surrounding belt structures 2 forms a gap 4;

Includes the following steps:

Step 1: Gap grinding before repair; grind the working surface of the first shroud structure 1 and the second shroud structure 2 before repair, and grind the gap 4 into a shape corresponding to the insert piece 6 to facilitate insertion. Piece 6 is assembled, mainly for grinding the working surfaces of the first shroud structure 1 and the second shroud structure 2 where the working surfaces rub against each other and the transition position is not smooth after wear, and the working surfaces of the first shroud structure 1 and the second shroud structure 2 are worn The burrs, warping, etc. left behind; grind the chamfered welding area on the working surface of the first shroud structure 1 for the welding of the insert 6. During grinding, protect the peripheral position of the gap 4 from damage. The final gap 4 requires a smooth transition of the wear position, and cleaning with alcohol is required to clean the surface;

Step 2: Select the insert piece 6; select the insert piece 6. The insert piece 6 is designed with specifications of different thicknesses. According to the maximum gap on one side of the gap 4 after grinding, select the second insert piece structure 62 with an appropriate thickness;

The thickness of the second insert structure 62 should be selected to be 0.3mm larger than the measurement gap;

Step 3: Repair the insert 6; repair the insert 6, clamp the insert 6 on a bench vise, grind the edges and corners of the insert 6 according to the contour of the gap 4, so that the grinding insert 6 can adapt to the gap 4 after repair. Insert the second insert structure 62 of the insert 6 into the gap 4. The first insert structure 61 is in contact with the surface of the second shroud structure 2 and is marked with a marking line to ensure the uniqueness of the position of the insert 6. The accuracy of the grinding of the blade 6; check the tightness of the contact between the insert 6 and the back side of the second shroud structure 2; use red red powder to check the contact between the insert 6 and the working surfaces of the first shroud structure 1 and the second shroud structure 2 For fit, the contact area should be greater than 75%;

Step 4: Welding the insert 6; Weld the insert 6, mechanically remove the oxide layer on the turbine blades and the parts to be welded on the insert 6, and wipe the inserts, the parts to be welded on the turbine blades and the vicinity of the welds with acetone or alcohol area; assemble the insert 6 into the gap 4 and fix it by spot welding, and perform welding repair according to the welding process specifications of the material;

Step 5: Non-destructive testing after repair; non-destructive testing, after the welding is completed, first conduct visual inspection. There should be no undercuts, pores, cracks and other defects in the first welding area 7 and the second welding area 8; the surface color of the welding seam should be the best. The best color is silvery white, followed by light yellow and golden yellow; if the welding seam is purple blue, dark blue, gray black, gray, gray white, it means that the welding seam has been contaminated by harmful gases and the welding seam is unqualified; in the welding seam and heat Penetration inspection is carried out in the affected area, and no defects are allowed to exist;

Step 6: Grind the repaired gap; grind the blade shroud after welding insert 6, and grind the first welding area Clean area 7 and second welding area 8, and grind off excess welding meat to ensure that the end of the blade shroud is flush with the blade shroud surface and must not be lower than the blade shroud surface;

Step 7: Non-destructive testing after grinding; for non-destructive testing, perform a visual inspection with a 10x magnifying glass on the surface of the first welding area 7 and the second welding area 8 again. There should be no undercuts, pores, cracks and other defects;

In step four, the insert 6 and the second shroud structure 2 are welded. First, mechanically remove the oxide layer on the second shroud structure 2 and the insert 6 to be welded, and wipe the insert 6 and the insert 6 with acetone or alcohol. At the parts to be welded and near the welds of the second shroud structure 2, assemble the inserts 6 according to the technical requirements and fix them by spot welding. Weld repairs are carried out according to the welding process specifications of the materials. Before welding, check the welding equipment and argon gas bottles. Pressure, adjust the argon protection equipment according to the welding position, so that it can provide good protection for the weld, back and gap heat-affected zone without affecting the welding operation; choose TA1 welding wire with a diameter of 1.6mm as the welding material. , The welding wire is not allowed to have cracks or interlayers. Wipe it clean with acetone or alcohol before use. Welding uses tungsten argon arc welding, the current is 40-75A, the argon gas flow is 10-15L/min, and the interlayer temperature is less than 60°C. High-frequency arc starting to prevent tungsten electrode from contaminating the weld. Use alcohol to clean the weld groove before welding, and feed the wire evenly and steadily to ensure that the welding area is effectively protected by argon gas. Use the advance/delay gas supply function of the welding equipment to ensure that the weld is well protected; due to the The secondary belt structure 2 and the insert 6 have high melting points, large heat capacity, and poor thermal conductivity. The welding seam and the near seam area are prone to grain growth. Therefore, the heat input must be strictly controlled during welding, and small current and fast welding must be used;

The welding equipment adopts an argon arc welding machine with high-frequency arc starting and advanced/delayed gas supply functions. The welding protective gas is high-purity argon with a purity of 99.999%;

The present invention uses welding inserts 4 to fill the gaps in the titanium alloy blade shrouds, and solves the problem of excessive gaps in the titanium alloy blade shrouds. For blades linked in a full circle, if the blade gap exceeds the standard, it is often necessary to replace the blades with new ones. , the method of filling the blade shroud gap, the cost of replacing a new titanium alloy blade is about RMB 200,000, and the cost of repairing a blade using the present invention is about RMB 2,000. Therefore, the present invention effectively reduces the cost of the steam turbine. The operation and maintenance cost of titanium alloy blades is reduced, and the blade shroud repair method is simple to operate, highly adaptable and versatile, and can be widely used to repair excessive gaps in the titanium alloy blade shrouds of steam turbines.

It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutations and combinations. Therefore, the present invention no longer applies to the permuted and combined technical solutions. Although explained one by one, it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.

This embodiment is only an illustrative description of this patent and does not limit its protection scope. Those skilled in the art can also make partial changes to it. As long as the spirit and essence of this patent are not exceeded, they are all within the protection scope of this patent.

Claims

A steam turbine titanium alloy blade shroud gap repair insert, which is characterized by: including a first insert structure (61) and a second insert structure (62). One end of the second insert structure (62) is connected to the first insert structure. The sheet structure (61) is arranged vertically, and the second insert structure (62) is composed of two arc surface structures and a planar structure with the same radius. The centers of the two arc surface structures are on the same horizontal line and have a certain distance. , the planar structure is in a horizontal state, the outer arc surface of the first insert structure (61) is connected to the arc surface structure inside the second insert structure (62), and the lower edges and left edges of the two are arranged opposite each other.
A steam turbine titanium alloy blade shroud gap repair method according to claim 1, characterized in that: the height of the second insert structure (62) is H1, and the height of the first insert structure (61) is H2, H1 >H2, the radius of the inner arc surface of the first insert structure (61) is smaller than the radius of the arc surface structure inside the second insert structure (62), the first insert structure (61) and the second insert structure (62) The inner arc surface structure is coaxially arranged. The arc angle of the first insert structure (61) is α, and the arc angle of the second insert structure (62) is greater than α.
A method for repairing the shroud gap of a steam turbine titanium alloy blade according to claim 2, characterized in that: the outer arc side of the second insert structure (62) is processed with a chamfer (63).
A method for repairing the gap of a titanium alloy blade shroud of a steam turbine, characterized in that: a titanium alloy blade shroud gap repairing insert according to claims 1 to 3 is used, the insert (6) comprises a second insert structure (62) and an insert structure (61) arranged perpendicular to the second insert structure (62), and the method comprises the following steps:

Step 1: Gap grinding before repair;

Step 2: Selection of insert (6);

Step 3: Repair the insert (6);

Step 4: Weld the insert (6);

Step 5: Non-destructive testing after repair;

Step 6: Grind the repaired gap;

Step 7: Non-destructive testing after grinding.
A steam turbine titanium alloy blade shroud gap repair method according to claim 4, characterized in that: the blade shroud includes a first shroud structure (1) and a second shroud structure (2), and the first shroud The belt structure (1) is connected to the second belt structure (2), and a gap (4) is formed by wear between the working surfaces of the first belt structure (1) and the second belt structure (2).
A steam turbine titanium alloy blade shroud gap repair method according to claim 5, characterized in that it includes the following steps:

Step 1: Grind the working surface of the first shroud structure (1) and the second shroud structure (2) before repair, and grind the gap (4) into a shape corresponding to the insert (6). The working surface of the first shroud structure (1) is ground to create a chamfered welding area. The gap (4) after grinding requires a smooth transition of the wear position. Clean it with alcohol to clean the surface;

Step 2: Select the insert (6). The insert (6) is designed with specifications of different thicknesses. According to the maximum gap on one side of the gap (4) after grinding, select the second insert structure (62) of appropriate thickness. );

Step 3: Repair the insert piece (6), clamp the insert piece (6) in a bench vise, and grind the edges and corners of the insert piece (6) according to the contour of the gap (4) so that the grinding insert piece (6) can adapt to grinding. After the gap (4), insert the second insert structure (62) of the insert (6) into the gap (4), and the first insert structure (61) is in contact with the surface of the second shroud structure (2) , and mark it with a marking line to check the tightness of the contact between the insert (6) and the back of the second shroud structure (2);

Step 4: Weld the insert (6), mechanically remove the oxide layer on the turbine blades and the parts to be welded on the insert (6), and wipe the inserts, the parts of the turbine blades to be welded and the areas near the welds with acetone or alcohol ;Assemble the insert (6) into the gap (4) and fix it by spot welding;

Step 5: Non-destructive inspection. After the welding is completed, first conduct a visual inspection. There should be no undercuts, pores, or crack defects in the first welding area 7 and the second welding area 8; the surface color of the welding seam should be silver white, light yellow or gold. yellow;

Step 6: Grind the blade shroud after welding the insert (6), clean the first welding area (7) and the second welding area (8), and grind excess welding meat to ensure that the end of the blade shroud is in contact with the The blade shroud surface is flush and shall not be lower than the blade shroud surface;

Step 7: Non-destructive testing. Conduct a visual inspection with a 10x magnifying glass on the surface of the first welding area (7) and the second welding area (8) again. There should be no undercuts, pores, or crack defects.
A method for repairing the shroud gap of a steam turbine titanium alloy blade according to claim 6, characterized in that in step two, the thickness of the second insert structure (62) is selected to be 0.3 mm larger than the measured gap.
A method for repairing the shroud gap of a steam turbine titanium alloy blade according to claim 6, characterized in that in step three, red red powder is used to check the insert (6) and the first shroud structure (1) and the second shroud. With respect to the fit of the working surface of the belt structure (2), the contact area should be greater than 75%.
A method for repairing the shroud gap of a steam turbine titanium alloy blade according to claim 6, characterized in that: in step four, the insert piece (6) and the second shroud structure (2) are welded and removed mechanically first. Use acetone or alcohol to wipe the oxide layer on the parts to be welded on the second shroud structure (2) and the insert piece (6), and wipe the parts to be welded on the insert piece (6) and the second shroud structure (2) and the vicinity of the weld, Assemble the insert (6) and fix it by spot welding. Check the welding equipment and argon gas bottle pressure before welding. Adjust the argon protection equipment according to the welding position so that it can be used without affecting the welding operation. Provide good protection for the weld, back and heat-affected zone; choose TA1 welding wire with a diameter of 1.6mm as the welding material. The welding wire is not allowed to have cracks or interlayers. Wipe it clean with acetone or alcohol before use. Welding uses tungsten arc welding. The current is 40-75A, the argon gas flow is 10-15L/min, the interlayer temperature is less than 60°C, and high-frequency arc is used.
A method for repairing the shroud gap of a steam turbine titanium alloy blade according to claim 9, characterized in that: the welding equipment adopts an argon arc welding machine.