Assembling and welding process for large rotary chamber

Abstract

The invention relates to an assembling and welding process for a large rotary chamber, which is characterized by comprising the following steps: S1, processing before assembling; s2, assembling a front arc section; s3, the compression part is assembled; s4, a seam flange and a supporting piece are assembled; s5, welding is conducted, specifically, the structure obtained in the step S4 is welded, but the joint closing flange is not welded; s6, overall assembly is conducted, specifically, after the prefabricated carbon steel section is assembled to the upper end face of the profiled part, the remaining weld joints are welded; and S7, the structure obtained in the step S6 is subjected to heat treatment, the *-shaped support is dismantled after annealing, and shape correction is conducted. The assembling and welding process has the beneficial effects that the problems of large-diameter S135 melon slice forming, assembling and welding deformation control, large assembling and welding stress and the like are successfully solved by adopting the assembling and welding process; according to the process, the construction period is obviously shortened by 1 / 3, the assembling and welding stress of martensitic stainless steel is greatly reduced, and the post-welding size deformation of a 7m-diameter runner chamber product is controlled within 5mm of a single side.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of water turbine components, in particular to an assembly and welding process for a large-scale rotary chamber. Background Art

[0002] The runner chamber is the core working part of the turbine. It is subject to harsh working conditions and often experiences cavitation and erosion. S135 is a super martensitic stainless steel specially used for hydropower. It has good corrosion resistance, wear resistance and fatigue resistance, but strong hardenability. In particular, the S135 large runner chamber contains the welding of carbon steel and super martensitic stainless steel. The expansion coefficients of the two materials are very different, and the shrinkage and stress after welding are large. How to assemble to minimize the welding stress and avoid cracking of the workpiece under stress after welding, heat treatment and service is a technical problem that needs to be solved urgently. Summary of the invention The invention aims at the technical problems existing in the prior art and provides a welding process for a large rotary chamber.

[0003] The technical solution of the present invention to solve the above technical problems is as follows: A welding process for a large rotary chamber comprises the following steps: S1. Pre-assembly treatment: After assembling the stand, fix two semicircular bottom flanges on the stand so that the end gaps of the two bottom flanges are opposite and the outer edges of the bottom flanges are located on the upper end surface of the stand; S2, assembling the front arc segment: draw a positioning line on the bottom flange in step S1, and then assemble and spot weld the front arc segment according to the positioning line. One bottom flange corresponds to one front arc segment, and the arc length of the front arc segment is less than or equal to the arc length of the corresponding bottom flange; S3, assembling the profiled part: the profiled part is composed of a plurality of arc-shaped segments, which are sequentially hoisted on the profiled part of step S2 and temporarily supported to form a circular profiled part; the longitudinal center line of the gap between the bottom flanges coincides with the longitudinal center line of the gap between the adjacent arc-shaped pieces arranged above them; and the carbon steel segments are prefabricated for standby use; S4. Install the joint flanges: first, pair the joint flanges in pairs and install them in the gap between the bottom flanges, so as to simultaneously connect the bottom flange, the front arc segment, and some arc segments on the profiled part, and the top of the joint flange extends above the top surface of the profiled part; then, install the longitudinal ribs, transverse ribs, and annular reinforcement ribs on the profiled part and the outer wall of the front arc segment; finally, after removing the internal temporary support, install the M-shaped support; S5, welding: welding the structure obtained in step S4, but the joint flange is not welded; S6. Overall assembly: After assembling the prefabricated carbon steel section on the upper end surface of the profiled part, weld the remaining weld; S7, heat treating the structure obtained in step S6, removing the cross-shaped support and adjusting the shape after annealing.

[0004] As a further technical solution, in step S1, before installing the bottom flange, a ground sample line needs to be drawn first so that the radial dimension is expanded unilaterally for inefficient welding shrinkage, and then the bottom flange is installed on the stand according to the ground sample line.

[0005] As a further technical solution, in step S3, a temporary lifting lug is provided on the inner wall of each arc segment for lifting and adjusting the shape.

[0006] As a further technical solution, in step S3, before each arc segment is hoisted, a three-dimensional template is used to check the profile, and during the inspection, the gap with the arc segment is controlled to be within 3 mm; The verticality of the three-dimensional template is within 1 mm.

[0007] As a further technical solution, the three-dimensional template includes at least three inspection plates and tie bars connecting the inspection plates, the straight side of the inspection plate is provided with a bayonet for installing the tie bars, and several inspection plates are gap-connected through the garbage, and the curved side of the inspection plate is used to check the profile of the arc segment; The curved side of the test plate is adapted to the edge curve of the arc segment in the height direction.

[0008] As a further technical solution, in step S3, angle and position adjustment are performed for each assembled arc segment.

[0009] As a further technical solution, in step S4, cross-shaped supports are horizontally provided at the upper and lower ends of the front arc segment and the profiled part from bottom to top.

[0010] As a further technical solution, in step S5, the welding process is as follows: S51, weld E of the annular reinforcement outside the welded structure; S52, longitudinal weld A in welded profile; S53, annular seam B between welded profile and front arc segment, and between front arc segment and bottom flange.

[0011] As a further technical solution, in step S3, when prefabricating the carbon steel section, first draw a ground sample line, calibrate the top flange, set up support, then draw a line on the top flange to install a straight cone tube, and perform intermittent base welding on the inside and outside. After one straight cone tube is installed on one top flange, they are treated as a whole, that is, two carbon steel sections are prepared for use.

[0012] As a further technical solution, in step S6, the longitudinal weld C between the joint flange and the front arc section and the profiled part is first welded to a depth of 1 / 3, and then the annular seam D between the carbon steel section and the profiled part is welded, and finally the longitudinal weld C is fully welded.

[0013] The beneficial effects of the present invention are as follows: the welding process of the present invention successfully overcomes the problems of large-diameter S135 melon slice forming, welding deformation control, and large welding stress; the process significantly shortens the construction period by 1 / 3, greatly reduces the welding stress of martensitic stainless steel, and the dimensional deformation of the 7m diameter wheel chamber product after welding is controlled within 5mm on a single side, which is better than the standard control requirement of 1MM / 1000mm, reaching the industry-leading level. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the structure of a large rotary chamber prepared in the embodiment; Figure 2 This is a schematic diagram of the rack structure used in Example 1; Figure 3 This is a schematic diagram of the structure of assembling the bottom flange in step S1 of Example 1; Figure 4 It is a structural schematic diagram of the front arc segment assembled in step S2 of embodiment 1; Figure 5 This is a schematic diagram of the structure of assembling the first arc-shaped segment in step S3 of Example 1; Figure 6 This is a schematic diagram of the structure of assembling the press-formed part in step S3 of Example 1; Figure 7 This is a partial structural schematic diagram of the assembly of the fitting seam flange in step S4 of Example 1; Figure 8 This is a schematic diagram of the structure of assembling the cross-shaped support in step S4 of Example 1; Fig. 9 This is a schematic diagram of the structure in which the carbon steel segment is assembled in step S6 of Example 1; Fig.10 It is a structural schematic diagram of the carbon steel section; Fig.11 This is a schematic diagram of the structure of a three-dimensional sample.

[0015] In the accompanying drawings, the components represented by the reference numerals are listed as follows: Stand 1, bottom flange 2, front arc section 3; Profiled part 4, arc segment 4a, temporary support 4b, temporary lifting lug 4c; Carbon steel section 5, joint flange 6, longitudinal rib plate 7, transverse rib plate 8, annular reinforcement rib 9, M-shaped support 10; Three-dimensional template 11, inspection plate 11a, tie rod 11b, bayonet 11c; Top flange 12 and straight cone cylinder 13. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0017] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0018] In the description of the present application, the term "for example" is used to mean "used as an example, illustration or description". Any embodiment described as "for example" in the present application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is given to enable any technician in the field to implement and use the present invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid unnecessary details to obscure the description of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in the present application.

[0019] Example 1 This embodiment is to solve the defect that the workpiece cracks under stress after welding, after heat treatment and during service due to the large difference in expansion coefficients of the two materials during the assembly process of the wheel chamber, and provides a welding process for a large wheel chamber, which specifically includes the following steps: S1. Pre-assembly treatment: After the rack 1 is matched, two semicircular bottom flanges 2 are fixed on the rack 1 so that the end gaps of the two bottom flanges 2 are opposite to each other and the outer edge of the bottom flange 2 is located on the upper end surface of the rack 1; (See Figure 2 , Figure 3 ) S2, assembling the front arc segment 3: draw a positioning line on the bottom flange 2 in step S1, and then assemble and spot weld the front arc segment 3 according to the positioning line. One bottom flange 2 corresponds to one front arc segment 3, and the arc length of the front arc segment 3 is less than or equal to the arc length of the corresponding bottom flange 2; (see Figure 4 ) S3, assembling the profiled part 4: the profiled part 4 is composed of a plurality of arc segments 4a, which are sequentially hoisted on the profiled part 4 of step S2 and a temporary support 4b is installed to form a circular profiled part 4; the longitudinal center line of the gap between the bottom flange 2 coincides with the longitudinal center line of the gap between the adjacent arc segments 4a arranged above it; at the same time, the prefabricated carbon steel segment 5 is reserved; (see Figure 5 , Figure 6 , Fig.10 ) S4, install the joint flange 6: first, match the joint flanges 6 in pairs and install them in the gap between the bottom flanges 2, so as to simultaneously connect the bottom flange 2, the front arc segment 3, and the partial arc segment 41 on the profiled part 4, and the top of the joint flange 6 extends above the top surface of the profiled part 4; then install the longitudinal rib plate 7, the transverse rib plate 8 and the annular reinforcement rib 9 on the outer wall of the profiled part 4 and the front arc segment 3; finally, after removing the internal temporary support 4b, install the M-shaped support 10; (see Figure 7 , Figure 8 ) S5, welding: welding the structure obtained in step S4, but the joint flange 6 is not welded; S6. Overall assembly: After assembling the prefabricated carbon steel section 5 on the upper end surface of the profiled part 4, weld the remaining weld; (See Fig. 9 ) S7, heat-treating the structure obtained in step S6, removing the cross-shaped support 10 after annealing, and correcting the shape.

[0020] In this example, a reasonable assembly and welding sequence is adopted to take into account both the construction period and the reduction of welding stress, effectively control the welding deformation, and ensure the welding size of the workpiece.

[0021] In the specific implementation process, Step S1, according to the size specifications of the workpiece, clean the assembly platform, determine the directions of the X and Y axes, and build the stand 1, for example, with a height of 500 mm.

[0022] Then draw a ground sample line to make the radial dimension unilaterally expand outward, for example, expand outward by 10mm for inefficient welding shrinkage, and then use the positioning block to place the bottom flange 2 on the stand 1 according to the ground sample line. At this time, the size of the stand 1 exceeds the outer contour of the bottom flange 2 by 50-100mm. In this embodiment, the bottom flange 2 is made of carbon steel.

[0023] In the specific implementation process, In step S3, a temporary lifting lug 4c is provided on the inner wall of each arc segment 4a for lifting and convenient adjustment. For example, the temporary lifting lug 4c is provided on the upper part of the inner wall of the arc segment 4a.

[0024] In the specific implementation process, In step S3, each arc segment 4a is formed by hot pressing at 1050°C, and then a three-dimensional template 11 (see Fig.11 ) Check the type line, and during the inspection process, the gap with the arc segment 4a must be controlled to be within 3mm, that is, there are no defects such as bulges, cracks, wrinkles, etc. on the surface. The surface meets the NB / T47013I level requirements through ultrasonic and coloring inspections to meet the use requirements. Furthermore, the gap is within 2mm; it can be explained that the arc segment 4a can be made of stainless steel; it should be explained that the verticality of the three-dimensional template 11 is within 1mm.

[0025] First, hoist the first arc segment 4a of the X-axis, and set a measuring platform and a laser leveling instrument (not shown in the figure) inside the space enclosed by the two bottom flanges 2 to monitor the transfer size and deformation. Specifically, the mechanical energy angle is adjusted by the distance from each arc segment to the center of the runner chamber, and the longitudinal position is checked and adjusted with a laser level. After assembly and positioning, temporary support 4b is performed using process steel pipes; then the remaining arc segments 4a are assembled according to the aforementioned process plan, and temporary support 4b is performed on all of them.

[0026] During the calibration process, for the protruding points, heat calibration is adopted on the outer wall, and cold water cannot be used. The shell is assisted by compressed air blowing; for the concave points, the outside is spot welded with basket bolts and pulled to the process size.

[0027] More specifically, the three-dimensional template 11 includes at least three inspection plates 11a and tie rods 11b connecting the inspection plates 11a. The straight side of the inspection plate 11a is provided with a snap-on 11c for installing the tie rods 11b. Several inspection plates 11a are gap-connected by the garbage. The curved side of the inspection plate 11a is used to check the profile of the arc segment 4a; the curved side of the inspection plate 11a is adapted to the edge curve of the arc segment 4a in the height direction.

[0028] When prefabricating the carbon steel section 5, first draw a ground sample line, calibrate the top flange 12, set up the support, then draw a line on the top flange 12 and install the straight cone tube 13, and intermittently weld the inside and outside. After one straight cone tube 13 is installed on one top flange 12, they are taken as a whole, that is, two carbon steel sections 5 are prepared for standby use, and the supports in the two prefabricated carbon steel sections 5 form a cross shape.

[0029] In the specific implementation process, In step S4, after the joint flanges 6 are paired, the side faces are first welded with positioning blocks, and the misalignment shall not be greater than 2 mm; then the local interference positions of the welded joint flanges 6 are polished and assembled to the gaps; When installing the M-shaped support 10, the support is executed in a "Bagua shape", with the M-shaped support 10 horizontally set in the front arc section 3, and the upper and lower ends of the profiled part 4 are horizontally set with M-shaped supports 10, and all the annular reinforcement ribs 9 and the outer periphery of the cylindrical structure (i.e., the workpiece) formed by them also need to be equipped with 8-10 process supports to reduce the welding deformation of the annular reinforcement ribs 9.

[0030] In the specific implementation process, In step S5, the welding process is as follows: S51, weld E of the annular reinforcement rib 9 outside the welded structure; S52, welding the longitudinal weld A in the profiled part 4; S53, welding the annular seam B between the profiled part 4 and the front arc segment 3, and between the front arc segment 3 and the bottom flange 2.

[0031] During the welding process, when welding vertically, the inside and outside of the groove should be welded symmetrically to reduce the change of the curvature of the cylinder after welding; and the joint flange 6 is temporarily not involved in the welding, and it will be adjusted and assembled according to the deformation after welding. (See Figure 1 ) In the specific implementation process, The two prefabricated carbon steel sections 5 are assembled on the upper end surfaces of the profiled part 4, and the M-shaped support 10 formed in the cylinder body forms a "Bagua shape". (See Fig. 9 ) In step S6, firstly weld the longitudinal weld C between the joint flange 6 and the front arc section 3 and the profiled part 4 to 1 / 3 of the depth, then weld the annular weld D between the carbon steel section 5 and the profiled part 4, and finally fully weld the longitudinal weld C. (See Figure 1 ) In the specific implementation process, In order to prevent deformation during heat treatment, the whole part is heat treated in the furnace. After heat treatment, the center face code plate is removed, that is, the left and right halves are separated after heat treatment to prevent stress release during heat treatment and deformation at the vertical face. After heat treatment annealing, all process supports are removed, and the dimensions are re-set and checked. The parts with large local deformation are calibrated with dynamic fire. The dimensions are checked, the axis and the petal connection are marked, and the machining allowance position is stamped as a reference line for machining. All welds on the flow surface are polished smooth.

[0032] During the welding process of this embodiment: 1. Welding material selection: S135+S135, using Harbin Welding Institute H13 / 5S, S135 and Q235 carbon steel welding, using E316LT1-1 flux-cored wire gas shielded welding; 2. Bevel welding sequence: The base material thickness is 65, all double-sided X grooves are used. The welding sequence of each weld is to weld the outer 1 / 3 depth first, then clean and grind the inner 2 / 3 depth, then weld the outer full, and finally weld the inner full; 3. The welding sequence for each pass: the circumferential seam is divided into sections along the circumference, and 4 people perform symmetrical back-welding and intermittent welding simultaneously; the longitudinal seam is welded from bottom to top, and 4 people perform synchronous welding.

[0033] 4. Preheating and interlayer temperature control: Use electric heating plates to cover the 150mm range on both sides of the weld. During the welding process, the temperature within the 100mm range near the groove is always kept between 100-150 degrees. The flame inside the groove is heated to 250 degrees before welding. This can ensure the fluidity of the molten pool and prevent excessive thermal expansion and deformation, as well as thermal cracks.

[0034] 5. Post-heating: To prevent cold cracks and dehydrogenation, heat the electric heating plate to 350 degrees immediately after welding, keep the weld warm for 2 hours, and then slowly cool it.

[0035] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0036] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0037] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A welding process for a large rotary chamber, characterized in that: The steps include: S1. Pre-assembly treatment: After the stand (1) is assembled, two semicircular bottom flanges (2) are fixed on the stand (1) so that the end gaps of the two bottom flanges (2) are opposite to each other and the outer edges of the bottom flanges (2) are located on the upper end surface of the stand (1); S2, assembling the front arc segment (3): draw a positioning line on the bottom flange (2) of step S1, and then assemble and spot weld the front arc segment (3) according to the positioning line, so that one bottom flange (2) corresponds to one front arc segment (3), and the arc length of the front arc segment (3) is less than or equal to the arc length of the corresponding bottom flange (2); S3, assembling the profiled part (4): the profiled part (4) is composed of a plurality of arc segments (4a), which are sequentially hoisted onto the profiled part (4) of step S2 and temporarily supported (4b) to form a circular profiled part (4); the longitudinal center line of the gap between the bottom flanges (2) coincides with the longitudinal center line of the gap between the adjacent arc segments (4a) arranged above them; and the prefabricated carbon steel section (5) is prepared for standby; S4, assembling the joint flanges (6): firstly mate the joint flanges (6) in pairs and then install them in the gap between the bottom flanges (2) so as to simultaneously connect the bottom flange (2), the front arc segment (3), and the partial arc segment (41) on the profiled part (4), and the top of the joint flange (6) extends above the top surface of the profiled part (4); then, install the longitudinal ribs (7), the transverse ribs (8) and the annular reinforcement ribs (9) on the outer wall of the profiled part (4) and the front arc segment (3); finally, after removing the internal temporary support (4b), install the M-shaped support (10); S5, welding: welding the structure obtained in step S4, but not welding the joint flange (6); S6. Overall assembly: After assembling the prefabricated carbon steel section (5) on the upper end surface of the profiled part (4), welding the remaining weld; S7, heat treating the structure obtained in step S6, removing the cross-shaped support (10) after annealing, and correcting the shape.

2. A welding process for a large rotary chamber according to claim 1, characterized in that: In step S1, before installing the bottom flange (2), a ground sample line must be drawn first so that the radial dimension is expanded outward on one side for inefficient welding shrinkage, and then the bottom flange (2) is installed on the stand (1) according to the ground sample line.

3. A welding process for a large rotary chamber according to claim 1, characterized in that: In the step S3, a temporary lifting lug (4c) is provided on the inner wall of each arc-shaped segment (4a) for lifting and adjusting the shape.

4. A welding process for a large rotary chamber according to claim 1, characterized in that: In the step S3, before each arc segment (4a) is hoisted, the three-dimensional template (11) is used to check the profile, and during the inspection, the gap with the arc segment (4a) is controlled to be within 3 mm; The verticality of the three-dimensional template (11) is within 1 mm.

5. A welding process for a large rotary chamber according to claim 4, characterized in that: The three-dimensional template (11) comprises at least three inspection plates (11a) and tie bars (11b) connecting the inspection plates (11a); a slot (11c) for installing the tie bars (11b) is provided on the straight side of the inspection plate (11a); a plurality of inspection plates (11a) are gap-connected via the tie bars (11b); and a curved side of the inspection plate (11a) is used to check the profile of the arc segment (4a); The curved side of the inspection plate (11a) is adapted to the edge curve of the arc segment (4a) in the height direction.

6. A welding process for a large rotary chamber according to claim 4, characterized in that: In the step S3, each time an arc segment (4a) is assembled, the angle and position are adjusted.

7. The welding process for a large rotary chamber according to claim 1, characterized in that: In the step S4, cross-shaped supports (10) are horizontally arranged at the upper and lower ends of the front arc segment (3) and the press-formed member (4) in sequence from bottom to top.

8. The welding process for a large rotary chamber according to claim 1, characterized in that: In step S5, the welding steps are as follows: S51, weld E of the annular reinforcement rib (9) outside the welded structure; S52, welding the longitudinal weld A in the profiled part (4); S53, welding the annular seam B between the profiled part (4) and the front arc segment (3), and between the front arc segment (3) and the bottom flange (2).

9. The welding process for a large rotary chamber according to claim 1, characterized in that: In the step S3, when prefabricating the carbon steel section (5), first draw a ground sample line, calibrate the top flange (12), and after arranging the support, draw a line on the top flange (12) to install the straight cone tube (13), and intermittently weld the inside and outside. After one top flange (12) is installed with one straight cone tube (13), they are taken as a whole, that is, two carbon steel sections (5) are prepared for use.

10. The welding process for a large rotary chamber according to claim 1, characterized in that: In step S6, the longitudinal weld C between the joint flange (6) and the front arc section (3) and the profiled part (4) is first welded to a depth of 1 / 3, then the circumferential weld D between the carbon steel section (5) and the profiled part (4) is welded, and finally the longitudinal weld C is fully welded.

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