Combined welding manufacturing process method for large-size water bucket type rotating wheel

Abstract

The invention discloses a combined welding manufacturing process method for a large-size water bucket type rotating wheel. A combined welding structure of a hub, a water bucket upper side wing, a water bucket lower side wing and an external water bucket is adopted. Martensitic stainless steel forgings are adopted for preparing hubs, external water buckets and water bucket side wings, non-consumable electrode gas shielded welding is adopted in high-stress areas of the water buckets, high weld joint quality and good weld joint metal impact toughness are obtained, the martensitic stainless steel forgings are basically equivalent to martensitic stainless steel forgings, and the performance of the martensitic stainless steel forgings is superior to that of micro cast-weld-state structures of additive materials; a linear or approximately linear multi-layer stacking path is adopted, so that the welding process is simplified, automatic welding is realized, and the welding quality is improved; narrow-gap non-gas metal arc welding equipment is adopted, and the weight of welding deposited metal is reduced, the manufacturing period is shortened, and the production efficiency is improved through a multi-layer stacking welding mode.

Description

Technical Field

[0001] The invention belongs to the technical field of production and manufacturing of impact runners, and in particular relates to a combined welding manufacturing process method for a large-size bucket runner. Background Art

[0002] With the needs of my country's economic development, the demand for energy continues to increase, and large-capacity impact hydropower units have become an inevitable option. The runner is the core component of the hydropower generator set. As the capacity of the unit increases, the size and weight of the runner also increase. At present, in order to solve the problem of the size limitation of the raw material forgings of large impact runners, the runner has to be divided into the runner hub, bucket flanks and external buckets for separate manufacturing. The runner hub is manufactured by integral forging processing, and the runner bucket flanks and external buckets are manufactured by forging welding or arc additive manufacturing. Among them, the impact runner welds of the ordinary forging welding structure are generally large grooves and are manufactured by manual welding. The weld structure also has the disadvantages of low impact toughness, large welding volume, and unstable quality control of manual welding welds; the arc additive manufacturing method usually has the disadvantages of poor performance of the weld part and low manufacturing efficiency. Summary of the invention

[0003] In view of this, the present invention provides a large-size bucket-type runner assembly welding manufacturing process method, which has the characteristics of high weld structure impact toughness, relatively small welding volume, automated welding, and stable weld quality control. The present invention is achieved through the following technical solutions:

[0004] S1. The large-size bucket runner adopts a combined welded structure of the hub, bucket upper wing, bucket lower wing and external bucket;

[0005] S2. Assemble the upper bucket wing and the lower bucket wing on the wheel hub, and perform multi-layer and multi-pass welding of the upper bucket wing, the lower bucket wing and the wheel hub along the groove path of the upper bucket wing and the groove path of the lower bucket wing respectively using a narrow gap non-melting electrode gas shielded welding gun, and the welding material is martensitic stainless steel welding wire;

[0006] S3, phased array ultrasound, pulse reflection ultrasound, and diffraction time-of-flight ultrasound equipment are used to perform nondestructive testing on the welds between the upper wing of the bucket, the lower wing of the bucket, and the wheel hub;

[0007] S4. Use CNC equipment to process the bilaterally symmetrical U-shaped narrow gap grooves for welding the wheel hub, the upper and lower wing of the bucket and the external bucket;

[0008] S5. Install external buckets on the wheel hub, bucket upper wing and bucket lower wing. Starting from the middle position of the external bucket groove path, use two narrow gap non-metallic electrode gas shielded welding guns to weld symmetrically on both sides of the groove at the same time. The welding depth is 10mm to 300mm. For the remaining welding depth of the groove, use a narrow gap non-metallic electrode gas shielded welding super-long welding gun to perform multi-layer stacking welding in the flat welding position;

[0009] S6, phased array ultrasound, pulse reflection ultrasound, and diffraction time-of-flight ultrasound equipment are used to perform nondestructive testing on the welds of the upper wing of the bucket, the lower wing of the bucket, the hub, and the external bucket;

[0010] S7. After combined welding, the large-size Pelton wheel is subjected to stress relief annealing at a temperature of 550°C to 600°C;

[0011] S8. Use CNC equipment to correct the dimensions of the upper wing, lower wing and external scoop lines of the scoop.

[0012] In the above-mentioned large-size bucket-type wheel combined welding manufacturing process method, the S5 is to assemble an external bucket on the wheel hub, the upper side wing of the bucket and the lower side wing of the bucket, start from the middle position of the external bucket groove path, and use a narrow gap non-melting electrode gas shielded welding gun to weld on one side of the groove, the welding depth is 10mm~300mm, and the unmelted metal at the root of the weld is polished and removed. For the remaining welding depth of the groove, a narrow gap non-melting electrode gas shielded welding super-long welding gun is used to perform multi-layer stacking welding in the flat welding position.

[0013] In the above-mentioned large-size bucket-type wheel combined welding manufacturing process method, the S5 is to assemble an external bucket on the wheel hub, the upper side wing of the bucket and the lower side wing of the bucket, and start from the middle position of the external bucket groove path, and use two narrow gap non-metallic electrode gas shielded welding guns to weld symmetrically on both sides of the groove at the same time, with a welding depth of 10mm to 300mm. For the remaining welding depth of the groove, a narrow gap metallic electrode gas shielded welding super-long welding gun is used to perform multi-layer stacking welding in a flat welding position.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1) The present invention uses martensitic stainless steel forgings to prepare the external bucket and bucket flanks. Non-melting electrode gas shielded welding is used in the high stress area of ​​the bucket. The welding impact toughness KV2 (0°C) is ≥120J, which is basically equivalent to the martensitic stainless steel forging parent material, and the performance is better than the micro-casting welded structure of the additive material;

[0016] 2) Using a straight or nearly straight multi-layer stacking path is conducive to simplifying the welding process, realizing automated welding, and improving welding quality;

[0017] 3) Through narrow gap welding equipment and multi-layer stacking welding methods, the weight of welding deposited metal can be reduced, the manufacturing cycle can be shortened, and production efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following is a brief introduction to the drawings required for use in the embodiments of the present invention.

[0019] Figure 1 It is a schematic diagram of the combined structure of the wheel hub, the upper side wing of the water bucket, the lower side wing of the water bucket, and the external water bucket and its welding path.

[0020] Figure 2 It is a schematic diagram of the welding groove structure of the wheel hub, the upper side wing of the water bucket, the lower side wing of the water bucket and the external water bucket.

[0021] Figure 3 This is a schematic diagram of the overall structure of a large-size Pelton impeller.

[0022] Description of Reference Numerals

[0023] 1-wheel hub; 2-buoy upper wing; 3-buoy lower wing; 4-external bucket; 5-root of weld between wheel hub, bucket upper wing, bucket lower wing and external bucket; 9-runner; 21-groove path of bucket upper wing; 31-groove path of bucket lower wing; 41-groove path of wheel hub, bucket upper wing, bucket lower wing and external bucket; 51-groove of welding between wheel hub, bucket upper wing, bucket lower wing and external bucket. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and technical effect of the present invention clearer, further explanation will be given below in conjunction with the drawings and specific embodiments, but each embodiment does not constitute a limitation of the present invention. The specific implementation methods described in the drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0025] Example 1

[0026] In this embodiment, a large-size Pelton wheel assembly welding manufacturing process method includes the following steps:

[0027] S1. The large-size bucket runner adopts a combined welded structure of the hub, bucket upper wing, bucket lower wing and external bucket, such as Figure 1 As shown;

[0028] S2. Install the upper bucket wing and the lower bucket wing on the wheel hub. Use a narrow gap non-melting electrode gas shielded welding gun to perform multi-layer and multi-pass welding along the groove path of the upper bucket wing and the groove path of the lower bucket wing. The welding material is a high-strength and toughness martensitic stainless steel welding wire with an impact toughness value of KV2 (0℃) ≥ 120J;

[0029] S3. After step S2 is completed, use phased array ultrasound, pulse reflection ultrasound, and diffraction time-of-flight ultrasound equipment to perform nondestructive testing on the welds between the upper wing of the bucket, the lower wing of the bucket, and the wheel hub;

[0030] S4. After the detection in step S3 is completed, the wheel hub, the upper wing of the water bucket, the lower wing of the water bucket and the external water bucket are welded with a bilaterally symmetrical U-shaped narrow gap groove, such as Figure 2 As shown;

[0031] S5. Assemble the external bucket on the wheel hub, bucket upper wing and bucket lower wing, and use two narrow gap non-metallic electrode gas shielded welding guns to weld symmetrically along the wheel hub, bucket upper wing, bucket lower wing and both sides of the external bucket groove path at the same time, with a welding depth of 10mm to 300mm. For the remaining welding depth of the groove, use a narrow gap non-metallic electrode gas shielded welding super-long welding gun to perform multi-layer stacking welding in the flat welding position;

[0032] S6. After step S5 is completed, use phased array ultrasound, pulse reflection ultrasound, and diffraction time difference ultrasound equipment to perform nondestructive testing on the welds of the upper wing of the bucket, the lower wing of the bucket, the hub, and the external bucket;

[0033] S7. The large-size water bucket after combined welding is subjected to stress relief annealing at a temperature of 550°C to 600°C;

[0034] S8. Use CNC equipment to modify the dimensions of the upper bucket wing, lower bucket wing and external bucket line, and finally obtain a complete large-size bucket runner, such as Figure 3 shown.

[0035] In this embodiment, martensitic stainless steel forgings are used to prepare the external water bucket and water bucket flanks. Non-melting electrode gas shielded welding is adopted in the high stress area of ​​the water bucket. The welding impact toughness KV2 (0℃) is ≥120J, which is basically equivalent to the martensitic stainless steel forging parent material, and the performance is better than the micro-casting welded state organization of the additive material. The use of a straight or nearly straight multi-layer stacking path is conducive to simplifying the welding process, realizing automated welding, and improving the welding quality. Through narrow gap welding equipment and multi-layer stacking welding methods, the weight of the welding deposited metal is reduced, the manufacturing cycle is shortened, and the production efficiency is improved.

[0036] Example 2

[0037] Based on Example 1, step S5 is differentiated, an external bucket is assembled on the wheel hub, the upper wing of the bucket and the lower wing of the bucket, and a narrow gap non-metallic electrode gas shielded welding gun is used to weld on one side of the groove starting from the middle position of the groove path of the external bucket, and the welding depth is 10 mm to 300 mm, and the root of the weld is polished and removed. For the remaining welding depth of the groove, a narrow gap non-metallic electrode gas shielded welding super-long welding gun is used to perform multi-layer stacking welding in a flat welding position;

[0038] Example 3

[0039] Based on Example 1, step S5 is differentiated, an external bucket is assembled on the wheel hub, the upper wing of the bucket and the lower wing of the bucket, and starting from the middle position of the groove path of the external bucket, two narrow gap non-metallic electrode gas shielded welding guns are used to weld symmetrically on both sides of the groove at the same time, and the welding depth is 10mm to 300mm. For the remaining welding depth of the groove, a narrow gap metallic electrode gas shielded welding super-long welding gun is used to perform multi-layer stacking welding in a flat welding position;

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it should be clear to those skilled in the art that the technical solutions described in the aforementioned embodiments may be modified, or some or all of the technical features therein may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A large-size Pelton wheel assembly welding manufacturing process, characterized in that: The following steps are involved: S1, a large-size bucket-type runner (9) adopts a combined welded structure of a hub (1), bucket upper wing (2), bucket lower wing (3) and an external bucket (4); S2. Assemble the upper bucket wing (2) and the lower bucket wing (3) on the wheel hub (1); perform multi-layer and multi-pass welding of the upper bucket wing (2), the lower bucket wing (3) and the wheel hub (1) along the groove path (21) of the upper bucket wing (2) and the groove path (31) of the lower bucket wing (3) using a narrow gap non-melting electrode gas shielded welding gun, respectively; the welding material is a martensitic stainless steel welding wire; S3, using phased array ultrasound, pulse reflection ultrasound, and diffraction time-of-flight ultrasound equipment to perform nondestructive testing on the welds between the bucket upper wing (2), the bucket lower wing (3) and the wheel hub (1); S4, using numerical control equipment to process the wheel hub (1), the upper wing of the bucket (2), the lower wing of the bucket (3) and the external bucket (4) for welding the bilaterally symmetrical U-shaped narrow gap groove (41); S5, assembling an external bucket (4) on the wheel hub (1), the bucket upper wing (2) and the bucket lower wing (3), starting from the middle position of the groove path (41) of the external bucket (4), using two narrow gap non-metallic electrode gas shielded welding guns to simultaneously and symmetrically weld on both sides of the groove (51), with a welding depth of 10 mm to 300 mm, and using a narrow gap non-metallic electrode gas shielded welding super-long welding gun to perform multi-layer stacking welding in a flat welding position for the remaining welding depth of the groove (51); S6, using phased array ultrasound, pulse reflection ultrasound, and diffraction time-of-flight ultrasound equipment to perform nondestructive testing on the welds of the bucket upper wing (2), the bucket lower wing (3), the wheel hub (1), and the external bucket (4); S7, after the assembly welding, the large-size Pelton wheel (9) is subjected to stress relief annealing at a temperature of 550° C. to 600° C.; S8. Use numerical control equipment to correct the dimensions of the upper wing (2), the lower wing (3) and the outer buoy (4) of the buoy.

2. The large-size Pelton wheel assembly welding manufacturing process according to claim 1 is characterized in that: In the S5, an external bucket (4) is assembled on the wheel hub (1), the bucket upper wing (2) and the bucket lower wing (3), and a narrow gap non-metallic electrode gas shielded welding gun is used to weld on one side of the groove (51) starting from the middle position of the groove path (41) of the external bucket (4), with a welding depth of 10 mm to 300 mm, and the unmelted metal at the weld root (5) is polished and removed, and the remaining welding depth of the groove (51) is carried out by using a narrow gap non-metallic electrode gas shielded welding super-long welding gun in a flat welding position to perform multi-layer stacking welding.

3. The large-size Pelton wheel assembly welding manufacturing process according to claim 1 is characterized in that: In the S5, an external bucket (4) is assembled on the wheel hub (1), the bucket upper wing (2) and the bucket lower wing (3), and starting from the middle position of the groove path (41) of the external bucket (4), two narrow gap non-metallic electrode gas shielded welding guns are used to simultaneously and symmetrically weld on both sides of the groove (51), with a welding depth of 10 mm to 300 mm. For the remaining welding depth of the groove (51), a narrow gap metallic electrode gas shielded welding super-long welding gun is used to perform multi-layer stacking welding in a flat welding position.

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