CN218117857U

CN218117857U - Steam turbine diaphragm

Info

Publication number: CN218117857U
Application number: CN202222491944.6U
Authority: CN
Inventors: 娄忠路; 林琪; 董丽君; 王金山; 温丹; 孔维雅; 高德臣
Original assignee: Siemens Energy Inc
Current assignee: Siemens Energy Inc
Priority date: 2022-09-20
Filing date: 2022-09-20
Publication date: 2022-12-23
Anticipated expiration: 2032-09-20

Abstract

The present disclosure provides a steam turbine diaphragm comprising: a first component (1) made of a first material, having a first connecting surface; a second component (2) made of a second material different from the first material, having a second connection surface; and a plurality of third members (3) made of a third material different from the first material, each of the third members (3) having an end portion embedded in one of the embedding holes on the second member (2) and having a third connecting surface at the end portion, the third connecting surface being exposed through the embedding hole so that the third connecting surface is located in the same plane as the first connecting surface and the second connecting surface and the third connecting surface are opposed to the first connecting surface; the second connection surface of the second component (2) and the third connection surface of the third component (3) are connected to the first connection surface of the first component (1) by means of an electron beam weld seam (A). The steam turbine diaphragm of the present disclosure can reduce welding deformation.

Description

Steam turbine diaphragm

Technical Field

The present disclosure relates to a steam turbine diaphragm.

Background

The steam turbine is a rotary steam power plant, also known as a steam turbine engine. When the high-temperature high-pressure steam turbine works, the high-temperature high-pressure steam passes through the fixed nozzle to become accelerated airflow and then is sprayed onto the blades, so that the rotor provided with the blade row rotates, and simultaneously, the rotor does work outwards.

Steam turbines generally comprise a rotating part (rotor) and a stationary part (stator). The rotating part comprises a main shaft, an impeller, a moving blade, a coupling and the like. The static part comprises a steam inlet part, a cylinder, a clapboard, a static cascade, a steam seal, a bearing and the like. The diaphragms in the stationary part serve to hold the stationary blades while dividing the cylinder into several chambers. The stationary blades of the first-stage diaphragm are also called nozzles, and the first-stage diaphragm and the nozzles thereof bear complex working conditions, so that the requirements on the materials, processing and manufacturing are very high.

In order to meet the technical performance requirements of complex working conditions on the partition plate and reduce the cost, the partition plate can adopt a mode of assembling and welding a plurality of parts. For example, the diaphragm may include a diaphragm fixing ring as a base, a blade connecting ring connected to the diaphragm fixing ring, and blades (stationary blades) mounted on the blade connecting ring. The baffle fixing ring can be made of relatively low-cost materials, and the blade connecting ring and the blades are made of high-strength materials. The vane connection ring is integrated with the diaphragm fixing ring by welding.

In order to reduce the cost, the wall thickness of the blade connecting ring is generally thinner than that of the baffle fixing ring, so that welding deformation is caused when welding is performed by adopting a traditional filling welding mode, and meanwhile, the position of the blade is changed, so that the technical requirement cannot be met.

Moreover, the deformation of the traditional welding technology is large, and the machining amount after welding needs to be large, so that the subsequent machining cost is high.

The present disclosure proposes a gas insulated switchgear that at least partially solves the drawbacks existing in the prior art.

SUMMERY OF THE UTILITY MODEL

The technical problem that this disclosure will solve is to provide a steam turbine baffle, can reduce welding deformation.

In order to solve the above technical problem, according to a first aspect of the present disclosure, there is provided a steam turbine diaphragm, comprising: a first component made of a first material, having a first connection surface, and having a first wall thickness in a direction perpendicular to the first connection surface; a second component made of a second material different from the first material, having a second connection surface and a second wall thickness in a direction perpendicular to the second connection surface, the second wall thickness of the second component being smaller than the first wall thickness of the first component; and a plurality of third members made of a third material different from the first material, each of the third members having an end portion embedded in one of the embedding holes on the second member and having a third connecting surface located at an end portion of the third member, the third connecting surface of the third member being exposed through the embedding hole such that the third connecting surface of the third member is located in the same plane as the first connecting surface of the first member and the second connecting surface of the second member and the third connecting surface of the third member are opposed to the first connecting surface of the first member; the second connection surface of the second component and the third connection surface of the third component are connected with the first connection surface of the first component by an electron beam weld.

In the present disclosure, an end portion of each of the third members is embedded in one of the embedding holes of the second member, and the second member and the third members are joined to the first member and connected at the joint by an electron beam weld. When the electron beam welding is used, a welding groove does not need to be formed in advance, the strength of the second part cannot be influenced, meanwhile, the electron beam welding is used for welding the fit clearance of the fit surface, the heat affected area generated by welding can be minimized, and therefore welding deformation is greatly reduced. In addition, the electron beam welding seam avoids introducing filling materials, the connecting surfaces on two sides are directly fused and connected together, compared with the traditional filling welding with beveling, only one welding seam is arranged, the deformation is small, therefore, the direct fine machining can be carried out after the heat treatment, and the remaining fine machining amount is much smaller than that of the traditional welding. In addition, the welding speed of the electron beam welding is higher than that of other welding speeds, so that the cost is further reduced, and the efficiency is improved. Moreover, as the electron beam welding seam avoids introducing a filling material, and the connection is realized only based on the melting of the parent metals at two sides, the chemical electrostatic corrosion (grain boundary corrosion) is reduced at the welding seam interface in use, and the working reliability is improved.

Further, according to an embodiment of the present disclosure, the first member and the second member are both annular members; the second component is located inside the first component, and the electron beam weld is an annular weld formed between the second component and the first component.

Since the second part is arranged at the inner side of the first part and an annular welding seam is formed between the second part and the first part, the fit clearance for assembling and electron beam welding can be very small, the first part at the outer side forms effective restraint for the second part at the inner side when electron beam welding is carried out, and the welding deformation is further reduced.

Further, according to an embodiment of the present disclosure, the plurality of third components are fixed to the second component by pre-fixing welds, which are argon arc welds.

The third component may be pre-secured within the second component by spot welding the second and third components, such as by argon arc welding, to facilitate forming an integral first combination for assembly and welding with the first component. This further improves the welding effect and the welding quality.

Further, according to an embodiment of the present disclosure, the first member is a separator fixing ring; the second component is a blade connecting ring; the third component is a blade; the electron beam welds include a first electron beam weld formed at a position on an upstream side of the turbine diaphragm between the first and second opposing joining surfaces and a third joining surface by a first electron beam weld and a second electron beam weld formed at a position on a downstream side of the turbine diaphragm between the first and second opposing joining surfaces and a third joining surface by a second electron beam weld performed after the first electron beam weld.

The first electron beam welding line and the second electron beam welding line are respectively formed on the downstream side and the downstream side of the steam turbine partition plate, so that the welding area of the fit clearance between the second component and the first component is fully welded, the welding and sealing effects on the upstream side and the downstream side can be guaranteed, the welding strength is further guaranteed, the damage of chemical electrostatic corrosion and the welding line due to the scouring and cutting action of air flow in high-speed steam is reduced, and the working reliability is further improved.

Further, according to an embodiment of the present disclosure, the first electron beam weld is connected with the second electron beam weld.

The first electron beam welding line and the second electron beam welding line are respectively formed on the downstream side and the downstream side of the steam turbine partition plate, so that the welding area of the matching gap between the second component and the first component and the welding area of the third component and the matching gap between the first component and the second component are fully welded, the welding and sealing effects on the upstream side and the downstream side can be guaranteed, the welding strength is further guaranteed, the damage to the welding lines due to chemical electrostatic corrosion and the scouring and cutting effect of air flow in high-speed steam is reduced, and the working reliability is further improved.

Further, according to an embodiment of the present disclosure, the second material and the third material are the same.

Due to the fact that the materials of the second component and the third component are the same, the physical and chemical properties of the electron beam welding seam between the second component and the first component are consistent, and therefore the uniformity and the reliability of the welding strength are further improved.

According to a second aspect of the present disclosure, there is provided a welding method for a steam turbine diaphragm, characterized by comprising the steps of: providing a first component, a second component, and a plurality of third components, wherein the first component is made of a first material, has a first connection surface, and has a first wall thickness in a direction perpendicular to the first connection surface; the second component is made of a second material, has a second connection surface, and has a second wall thickness in a direction perpendicular to the second connection surface; and the third component is made of a third material and has a third connecting surface; wherein the first material is different from the second and third materials; assembling the second and third components to form a first assembly, wherein the third component is embedded within an embedding aperture on the second component such that the second and third connection surfaces are flush in the assembly; assembling the first assembly with the first component to form a second assembly such that the second connection surface of the second component and the third connection surface of the third component mate with the first connection surface of the first component and form a mating gap; and welding a fit clearance between the second connecting surface of the second component and the third connecting surface of the third component and the first connecting surface of the first component by electron beam welding to form an electron beam welding seam.

Further, according to an embodiment of the present disclosure, before the step of assembling the first assembly with the first component to form a second assembly, the method further includes performing pre-fixing welding on the second component and a third component in the assembly by argon arc welding to form a pre-fixing weld between the second component and the third component.

Further, according to an embodiment of the present disclosure, the first member and the second member are both annular members; the second component being located inside the first component, wherein the step of welding with electron beam welding a mating gap between the second connection surface of the second component and the third connection surface of the third component with the first connection surface of the first component to form an electron beam weld comprises, in order: seal welding the fit-up gap by electron beam welding on a first side of the second assembly corresponding to an upstream side of the turbine diaphragm to form a first electron beam weld; form welding the fit-on gap at a second side of the second assembly corresponding to a downstream side of the turbine diaphragm by electron beam welding to form a second electron beam weld.

Therefore, the steam turbine partition plate effectively solves the problem of welding deformation of thin-wall parts in the partition plate, improves the processing quality, the production efficiency and the working reliability, and reduces the production cost.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and not to limit the disclosure. In the drawings:

FIG. 1A is an axial schematic view of a steam turbine diaphragm according to the present disclosure;

FIG. 1B is an enlarged, fragmentary, schematic view of a section M of the steam turbine diaphragm shown in FIG. 1A;

FIG. 2 is a schematic cross-sectional view of section M of the steam turbine diaphragm shown in FIG. 1A;

FIG. 3 is a schematic flow diagram of a welding method for a steam turbine diaphragm according to the present disclosure.

The reference numbers indicate:

1. a first member; 2. a second component; 3. a third component;

A. electron beam welding; a1, a first electron beam weld; a2, second electron beam welding seams;

B. and (4) pre-fixing the welding seam.

Detailed Description

The technical solutions in the embodiments of the present disclosure will be described clearly and completely with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the embodiments described are only some embodiments of the present disclosure, rather than all embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without inventive step, are intended to be within the scope of the present disclosure.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise.

Fig. 1A is an axial structural view of a steam turbine diaphragm according to the present disclosure, fig. 1B is a partially enlarged structural view of an M portion of the steam turbine diaphragm shown in fig. 1A, and fig. 2 is a sectional structural view of the M portion of the steam turbine diaphragm according to the present disclosure. Referring to fig. 1A, 1B and 2, it can be seen that the steam turbine diaphragm of the present disclosure includes: a first part 1, a second part 2 and a plurality of first parts 1. Wherein the first part 1, made of a first material, has an upper surface (as seen in fig. 1B and 2) forming a first connection surface and has a first wall thickness in a direction perpendicular to the first connection surface. The second part 2, which is made of a second material, has a lower surface (as viewed in fig. 1B and 2) forming a second connection surface and has a second wall thickness in a direction perpendicular to the second connection surface. As can be seen from fig. 1B and 2, the second wall thickness of the second component 2 is smaller than the first wall thickness of the first component 1. A plurality of third members 3 made of a third material, whose lower surfaces (as viewed in fig. 1B and 2) form third connection surfaces. The second member 2 and the third member 3 are welded to the first member 1.

According to an embodiment of the present disclosure, the first material is different from the second material and the third material. For example, the first material may be a American Standard A36 steel, and the second and third materials may be American Standard 405 steel.

According to an embodiment of the present disclosure, the first member 1 and the second member 2 are both annular members. The first component 1 is a clapboard fixing ring, the second component 2 is a blade connecting ring, and the third component 3 is a blade. The first attachment surface of the first part 1 is the inner surface of the diaphragm mount and the second attachment surface of the second part 2 is the outer surface of the blade attachment tab. The second component 2 is located inside the first component 1 and the electron beam weld is an annular weld formed between the second component 2 and the first component 1.

Referring to fig. 2 in conjunction with fig. 1A and 1B, it can be seen that each third member 3 has an end portion (lower end of the third member 3 shown in fig. 2) which is fitted in a fitting hole on the second member 2, the third member 3 further has a third connecting surface (lower end surface of the third member 3 shown in fig. 2) located at the end portion of the third member 3, which is exposed through the lower end opening of the fitting hole so that the third connecting surface of the third member is located in the same plane as the first connecting surface of the first member, and the second connecting surface of the second member 2 and the third connecting surface of the third member 3 are opposed to the first connecting surface of the first member 1; the second connection surface of the second member 2 and the third connection surface of the third member 3 are connected to the first connection surface of the first member 1 by an electron beam welding seam a.

As can be seen from fig. 2, the electron beam weld a includes a first electron beam weld A1 directed toward an upstream side of the turbine diaphragm and a second electron beam weld A2 directed toward a downstream side of the turbine diaphragm, the first electron beam weld A1 being formed at a position on the upstream side of the turbine diaphragm between the first and second and third opposite connection surfaces by a first electron beam welding, and the second electron beam weld A2 being formed at a position on the upstream side of the turbine diaphragm between the first and second and third opposite connection surfaces by a second electron beam welding performed after the first electron beam welding. As can also be seen in fig. 2, in a preferred embodiment, the first electron beam weld A1 is connected to the second electron beam weld A2.

In the present disclosure, the third member is embedded in the embedding hole of the second member, and the second member and the third member are mated with the first member and connected by an electron beam weld at the mating. When the electron beam welding is used, a welding groove does not need to be formed in advance, the strength of the second component cannot be influenced, meanwhile, the electron beam welding is used for welding the fit clearance of the fit surface, the heat affected area generated by welding can be minimized, and therefore welding deformation is greatly reduced.

In addition, the electron beam welding seam is adopted in the method, so that the introduction of filling materials is avoided, the matching surfaces on the two sides are directly connected together in a melting mode, compared with the traditional filling welding with a groove, only one welding seam is arranged, the deformation is small, the direct fine machining can be carried out after the heat treatment, and the remaining fine machining amount is much smaller than that of the traditional welding.

In addition, the welding speed of the electron beam welding is higher than that of other welding speeds, so that the cost is further reduced, and the efficiency is improved.

Moreover, as the electron beam welding seam avoids introducing filling materials and realizes connection only based on the fusion of the parent metals on two sides, the welding seam interface reduces chemical electrostatic corrosion grain boundary corrosion in use and improves the working reliability.

Furthermore, in the present disclosure, since the second component is inside the first component with an annular weld formed therebetween, the fit-up clearance for assembly and electron beam welding can be very small, and the outside first component forms effective restraint to the inside second component when electron beam welding is performed, further reducing welding deformation.

With additional reference to fig. 2, it can be seen that the third component 3 is secured to the second component 2 by a pre-fixing weld B, which is an argon arc weld. The third component may be pre-secured within the second component by spot welding the second and third components, such as by argon arc welding, to form an integral first assembly for assembly and welding with the first component. This further improves the welding effect and the welding quality.

In addition, in this disclosure, by forming the first electron beam welding line and the second electron beam welding line on the downstream side and the downstream side of the turbine diaphragm, it is ensured that the welding area at the fitting clearance between the second member and the first member and the third member is sufficiently welded, and the welding and sealing effects on the upstream side and the downstream side can be ensured, thereby further ensuring the welding strength, reducing the damage to the welding lines due to the erosion cutting action of the air flow in the high-speed steam, and further improving the operational reliability.

In addition, in embodiments of the present disclosure, the second material and the third material are the same. Due to the fact that the materials of the second component and the third component are the same, the physical and chemical properties of the electron beam welding seam between the second component and the first component are consistent, and therefore the uniformity and the reliability of the welding strength are further improved.

FIG. 3 is a schematic flow diagram of a welding method for a steam turbine diaphragm according to the present disclosure. The welding method of the present disclosure is explained below with reference to fig. 3.

In an embodiment of the present disclosure, a welding method for a steam turbine diaphragm includes the steps of:

s1: a first component 1, a second component 2 and a plurality of third components 3 are provided.

Wherein the first component 1 is made of a first material, has a first connection surface, and has a first wall thickness in a direction perpendicular to the first connection surface; the second part 2 is made of a second material, has a second connection surface and has a second wall thickness in a direction perpendicular to the second connection surface; the third part 3 is made of a third material and has a third connecting surface; wherein the first material is different from the second material and the third material.

S2: the second component 2 and the third component 3 are assembled to form a first combination.

Wherein the third part 3 is embedded in the embedding hole in the second part 2 such that in the combination the second connection surface and the third connection surface are flush.

S3: the second member 2 and the third member 3 in the combined body were pre-fixed welded by argon arc welding.

This is a preferred step. This step S3 is performed to form a pre-fixing weld B between the second component 2 and the third component 3, prior to the step of assembling the first combination with the first component 1 to form the second combination. In this way, the third component can be pre-secured within the second component to facilitate forming an integral first assembly for subsequent assembly and welding with the first component. This further improves the welding effect and the welding quality.

S4: the first assembly is assembled with the first component 1 to form a second assembly.

In this step, the second connecting surface of the second component 2 and the third connecting surface of the third component 3 are brought into fit with the first connecting surface of the first component 1 and form a fit gap.

In the embodiment according to the present disclosure, the first member 1 and the second member 2 are both annular members; the second part 2 is located inside the first part 1.

Next, the fitting gap between the second connecting surface of the second member 2 and the third connecting surface of the third member 3 and the first connecting surface of the first member 1 is welded by electron beam welding, forming an electron beam weld a.

According to an embodiment of the present disclosure, the step of welding the fitting gap between the second connection surface of the second member 2 and the third connection surface of the third member 3 and the first connection surface of the first member 1 by electron beam welding to form the electron beam weld a includes, in order:

s5: the mating gap is seal welded (first electron beam welding) on the first side of the second assembly to form a first electron beam weld A1.

Wherein the first side of the second assembly corresponds to an upstream side of the turbine diaphragm. In this step, the fitting gap is seal-welded on the first side of the second assembly by electron beam welding to form a first electron beam weld A1.

S6: form welding (second electron beam welding) is performed on the mating gap on the second side of the second assembly to form a second electron beam weld A2.

Wherein the second side of the second assembly corresponds to a downstream side of the turbine diaphragm. In this step, the fit-up gap is form-welded on the second side of the second assembly by electron beam welding to form a second electron beam weld A2.

Because the working condition of the steam turbine partition plate is complex, the steam turbine partition plate has humidity and static electricity, and the welding seam itself can have micro cracks. In the present disclosure, the step of forming an electron beam weld by electron beam welding is divided into two parts, welding is started from one side of the erosion end (i.e., the upstream end of the turbine diaphragm), the fitting gap is sealed, and then electron beam welding is performed from the opposite side of the erosion end (i.e., the downstream end of the turbine diaphragm) toward the erosion end to form a double-sided weld.

The first part (i.e., the first electron beam welding of step S5) performed previously is used to adhere the first assembly and the first part together with the first electron beam weld A1. In this step, the first assembly is least constrained in the first component, is most adaptable, and is more likely to form a high quality weld. The welding seam has better sealing effect. This previously performed step S5 may be referred to as seal welding. The first electron beam welding seam A1 with good sealing effect is formed on the upstream side of the steam turbine partition plate, so that electrostatic corrosion and particle scouring generated by high-speed steam can be better prevented from damaging the inside of the welding seam.

The second part of the later execution (i.e. the second electron beam welding in step S6) forms a second electron beam welding seam A2 on the downstream side of the steam turbine diaphragm, and forms a sealed cabin together with the first electron beam welding seam. Even a small fraction of non-melted sites in the middle are acceptable. This later performed step S6 may be referred to as form welding.

The seal weld and the form weld may be the same on the process itself, both belonging to electron beam welding.

In the embodiment of the disclosure, the seal welding is performed on the upstream side of the turbine diaphragm, and then the forming welding is performed on the downstream side of the turbine diaphragm, and the step of forming the electron beam welding seam a is sequentially divided into two welding steps, so that a place with a relatively large hazard (the upstream side of the turbine diaphragm) is formed (the first electron beam welding seam A1 is formed) first, and the place is in a good state in an initial stage. Then, the back surface (the downstream side of the turbine diaphragm) is reinforced by a second electron beam welding bead A2. Since the rear side of the diaphragm is inherently less subject to erosion and less subject to pressure, the welding of this side can be used as a final weld, so that the overall electron beam weld has the best welding strength and operational reliability.

In the embodiment of the present disclosure, by setting parameters such as the current of the electron beam welding, the welding depth of the electron beam weld can be adjusted, so that the first electron beam weld A1 and the second electron beam weld A2 are ensured to be connected, thereby ensuring the welding strength.

The foregoing is merely a preferred embodiment of the present disclosure, and it should be noted that modifications and embellishments could be made by those skilled in the art without departing from the principle of the present disclosure, and these should also be considered as the protection scope of the present disclosure.

Claims

1. Steam turbine baffle, its characterized in that includes:

a first part (1) made of a first material, having a first connection surface and a first wall thickness in a direction perpendicular to the first connection surface;

a second part (2) made of a second material different from the first material, having a second connection surface and a second wall thickness in a direction perpendicular to the second connection surface, the second wall thickness of the second part (2) being smaller than the first wall thickness of the first part (1); and

a plurality of third members (3) made of a third material different from the first material, each of the third members (3) of the plurality of third members (3) having an end portion embedded in one embedding hole on the second member (2) and having a third connecting surface at the end portion of the third member, the third connecting surface of the third member being exposed through the embedding hole such that the third connecting surface of the third member is located in the same plane as the first connecting surface of the first member, and the second connecting surface of the second member (2) and the third connecting surface of the third member (3) are opposed to the first connecting surface of the first member (1);

the second connecting surface of the second component (2) and the third connecting surface of the third component (3) are connected to the first connecting surface of the first component (1) by means of an electron beam weld seam (A).

2. The steam turbine diaphragm according to claim 1,

the first part (1) and the second part (2) are both annular parts;

the second component (2) is located inside the first component (1), and the electron beam weld is an annular weld formed between the second component (2) and the first component (1).

3. The steam turbine diaphragm according to claim 1,

the third parts (3) are fixed on the second part (2) through pre-fixing welding seams (B), and the pre-fixing welding seams (B) are argon arc welding seams.

4. The steam turbine diaphragm according to claim 1,

the first component (1) is a clapboard fixing ring;

the second component (2) is a blade connecting ring;

the third part (3) is a blade;

wherein the electron beam weld (A) includes a first electron beam weld (A1) formed at a position on an upstream side of the turbine diaphragm between the first and second opposite connection surfaces and a third connection surface by a first electron beam welding and a second electron beam weld (A2) formed at a position on a downstream side of the turbine diaphragm between the first and second opposite connection surfaces and a third connection surface by a second electron beam welding performed after the first electron beam welding.

5. The steam turbine diaphragm according to claim 4,

the first electron beam weld seam (A1) is connected to the second electron beam weld seam (A2).