Welding process of motor shaft for general assembly type luxury cruise ship main propeller

Abstract

The invention relates to a welding process of a motor shaft for a main propeller of a final assembly type luxury cruise ship, which not only can produce the final assembly type motor shaft with high quality and low manufacturing cost, but also can improve the production efficiency and ensure the delivery cycle. A 60-degree V-shaped groove with the same size inside and outside is adopted, an internal groove is firstly machined and polished, a small groove with the depth of 3 mm is pre-formed in an outer circle, and after internal welding is completed and flaw detection is qualified, an external groove is completely machined; the rotary bracket is used for rotating the workpiece at a constant speed to realize welding while rotating the workpiece; the interior of the motor shaft is welded in a gas shielded welding mode, the welding current is 150-300 A, the voltage is 20-30 V, the welding speed is 30-48 mm / min, the exterior of the motor shaft is welded in a submerged-arc welding mode after three manual welding bottoming is conducted at the bottom, and the welding current is 470-600 A, the voltage is 30-36 A, and the welding speed is 300-400 mm / min through submerged-arc welding; in order to keep the temperature of the welding part, a hoop is manufactured for placing an electric blanket; when the interior of the motor shaft is welded, a welder sits on a cantilever crane, an exhaust fan is placed behind the welder, a ventilation pipeline is placed behind the exhaust fan, then smoke generated by internal welding is exhausted, the internal air quality is guaranteed, and the internal temperature is reduced.

Description

Technical Field

[0001] The invention relates to a welding process for a motor shaft for a main propulsion unit of a luxury cruise ship, which can produce a high-quality, low-cost assembled motor shaft and improve production efficiency and ensure delivery cycle, and belongs to the field of large-scale ship motor shaft manufacturing. Background Art

[0002] At present, there are only a few manufacturers of forgings for assembled motor shafts. With the increase of large ship manufacturers, forging manufacturers have been provided with development opportunities. However, how to produce high-quality, low-cost assembled motor shafts and ensure delivery cycles are new issues facing forging manufacturers. Because there is no implementation plan for welding motor shafts for main propulsion of assembled luxury cruise ships.

[0003] The welding drawing provided by the customer shows that the groove is small inside and large outside. This type of groove is easy to change after the actual welding, and the bottom weld is prone to cracks and other defects after the internal welding is completed and before the external welding. At the same time, in order to ensure the welding quality, more bottom welds will be planed off before external welding. If the groove is based on the customer's drawing, the margin will be insufficient, which is not suitable for such welding parts with very high precision requirements. Summary of the invention

[0004] Design purpose: To avoid the shortcomings of the background technology, a welding process for the motor shaft of the main propulsion unit of an assembled luxury cruise ship is designed, which can ensure both the assembly centerline and the high precision requirements of the workpiece, and keep the deformation of the workpiece within a controllable range during the welding process, while allowing the operator to enter the motor shaft for safe welding operations.

[0005] Design scheme: In order to achieve the above-mentioned design objectives. The present invention has the following manufacturing process design: 1. The motor short shaft and the rotor core are assembled by adopting a stopper. Heat the external stopper, utilize the principle of thermal expansion and contraction, and assemble in a vertical assembly manner to ensure its concentricity. After the assembly is completed and the workpiece is cooled, ribs are welded around the connection parts for reinforcement to tighten the rotor core and the short shaft. After the internal welding is completed, the external reinforcement ribs are removed. 2. The welding drawings provided by the customer show that the groove is a small inner groove and a large outer groove (this type of groove is easy to deform after welding, and after the internal welding is completed and before the external welding, the bottom weld is prone to cracks and other defects. In order to ensure the welding quality, more bottom welds will be planed off, and then the external welding will be carried out. If the groove in the drawing is followed, the margin will not be enough). In order to ensure the welding quality, the present invention has designed a new groove scheme, that is, a 60° V-shaped groove with the same size inside and outside. First, the internal groove is processed and polished, and a small groove with a depth of 3mm is pre-opened on the outer circle. After the internal welding is completed and the flaw detection is qualified, the external groove is completely processed, which can more effectively control the deformation caused by welding. 3. In order to ensure the smooth progress of welding and to ensure the uniformity of the weld, the present invention uses a rotary bracket to rotate the workpiece at a uniform speed to achieve welding while the workpiece is rotating. 4. The internal welding is carried out by gas shielded welding, with a welding current of 150-300A, a voltage of 20-30V, and a welding speed of 30-48mm / min. After each weld is completed, the root is cleaned and the slag is removed to ensure the welding quality. After the internal overall welding is completed, flaw detection is carried out. For the outside, three manual welds are first welded on the bottom to lay the base, and then submerged arc welding is used for welding. Submerged arc welding uses a welding current of 470-600A, a voltage of 30-36A, and a welding speed of 300-400mm / min. After welding, flaw detection is carried out. After the flaw detection is qualified, annealing is carried out. After annealing, flaw detection is carried out again. 5. In order to maintain the temperature of the welding part, a clamp is made to place the electric blanket. During the welding operation, the temperature is monitored in real time with a temperature measuring gun. The temperature is kept at around 100°C. When the temperature drops, welding is stopped and heating is performed. 6. During internal welding, the welder sits on the armrest and does not directly contact the workpiece to ensure welding accuracy. An exhaust fan is placed behind the welder, and a ventilation duct is placed behind the exhaust fan to discharge the smoke generated by internal welding, ensure the internal air quality, and reduce the internal temperature. The welder wears protective tools to prevent harm to his health. Arrange two welders to work alternately, and replace them every fifteen minutes of welding.

[0006] Compared with the background technology, the present invention solves the problem of difficult assembly and inability to ensure concentricity; secondly, the dedicated welding groove, welding method and welding tooling ensure that the deformation of the workpiece during the welding process is within a controllable range and the manufacturing accuracy is ensured; the arrangement of deep ventilation ducts inside the rotor core improves the harsh welding environment inside the rotor core and ensures that the welding personnel can operate normally and ensure safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a cross-sectional schematic diagram of the present invention.

[0008] Figure 2 yes Figure 1 Schematic diagram of the local structure of the welding process. DETAILED DESCRIPTION

[0009] See attached Figure 1 and 2 A welding process for the motor shaft of the main propulsion unit of a general assembly luxury cruise ship: 1) The short shaft and the rotor core are assembled by means of a stopper, the external stopper is heated, and the concentricity is ensured by utilizing the principle of thermal expansion and contraction and assembling in a vertical assembly manner. After the assembly is completed and the workpiece is cooled, ribs are welded around the connection parts to reinforce the rotor core and the short shaft. After the internal welding is completed, the external reinforcement ribs are removed; 2) A 60° V-shaped groove with the same size inside and outside is used, the internal groove is first processed and polished, and a small groove with a depth of 3mm is pre-opened on the outer circle. After the internal welding is completed and the flaw detection is qualified, the external groove is completely processed; 3) A rotary bracket is used to rotate the workpiece at a uniform speed to achieve welding while the workpiece is rotating. 4) The motor shaft is welded internally by gas shielded welding, with a welding current of 150-300A, a voltage of 20-30V, and a welding speed of 30-48mm / min. After each weld, the root is cleaned and the slag is removed. After the internal welding is completed, flaw detection is performed. For the external part, three manual welds are first welded at the bottom to prime it, and then submerged arc welding is used. Submerged arc welding uses a welding current of 470-600A, a voltage of 30-36A, and a welding speed of 300-400mm / min. After welding is completed, Perform NDT, and anneal after passing the NDT. Perform another NDT after annealing is completed; 5) In order to maintain the temperature of the welding part, make a clamp to place the electric blanket. Use a temperature gun to monitor the temperature in real time during welding. The temperature is kept at around 100°C. When the temperature drops, stop welding and heat; 6) When welding the inside of the motor shaft, the welder sits on the armrest, and an exhaust fan is placed behind the welder. A ventilation duct is placed behind the exhaust fan to discharge the smoke generated by the internal welding, ensure the internal air quality, and reduce the internal temperature.

[0010] It should be understood that although the above embodiments provide a relatively detailed textual description of the design ideas of the present invention, these textual descriptions are only simple textual descriptions of the design ideas of the present invention, rather than limitations on the design ideas of the present invention. Any combination, addition or modification that does not exceed the design ideas of the present invention shall fall within the protection scope of the present invention.

Claims

1. A welding process for the motor shaft of a main propeller of an assembled luxury cruise ship, characterized by: 1) The short shaft and the rotor core are assembled by means of stoppers. The external stoppers are heated and assembled by means of vertical assembly using the principle of thermal expansion and contraction to ensure concentricity. After the assembly is completed and the workpiece is cooled, ribs are welded around the connection parts to reinforce the rotor core and the short shaft. After the internal welding is completed, the external reinforcement ribs are removed; 2) Use a 60° V-shaped groove with the same size inside and outside. First, process the inner groove and grind it, and pre-open a small groove with a depth of 3mm on the outer circle. After the internal welding is completed and the flaw detection is qualified, the outer groove is processed; 3) Use a rotary bracket to rotate the workpiece at a constant speed to achieve welding while the workpiece is rotating. 2.4) The inside of the motor shaft is welded by gas shielded welding, with a welding current of 150-300A, a voltage of 20-30V, and a welding speed of 30-48mm / min. After each weld, the root is cleaned and the slag is removed. After the internal overall welding is completed, flaw detection is carried out. For the outside, three manual welds are first welded at the bottom to lay the base, and then submerged arc welding is used for welding. Submerged arc welding uses a welding current of 470-600A, a voltage of 30-36A, and a welding speed of 300-400mm / min. After welding, flaw detection is carried out, and after the flaw detection is qualified, annealing is carried out, and flaw detection is carried out again after annealing; 5) In order to maintain the temperature of the welding part, make a hoop to place the electric heating blanket. Use a temperature measuring gun to monitor the temperature in real time during welding. The temperature is kept at around 100°C. When the temperature drops, stop welding and heat. 6) When welding the inside of the motor shaft, the welder sits on the armrest, an exhaust fan is placed behind the welder, and a ventilation duct is placed behind the exhaust fan to discharge the smoke generated by the internal welding, thereby ensuring the internal air quality and reducing the internal temperature.

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