Shaft machining process of steam turbine generator shaft
Turbine generator shaft processing technology includes many:
Such as shaft forging inspection and cutting test, turning sequence processing technology, milling processing technology, boring sequence processing technology. Used in the rotary shaft material has certain requirements. Let's introduce each of these contents separately.
First, the rotating shaft material
The large-capacity turbine rotor core is made of high-quality alloy steel forgings with high mechanical strength and good magnetic permeability (such as nickel-chromium molybdenum vanadium, nickel-chromium vanadium, vanadium-nickel-molybdenum, etc.). For large steam turbine generators of thermal power stations, such motor shafts requiring load changes and frequent start and stop during operation, most of the large and large steam turbine generator rotor shafts at home and abroad use NiCrMoV steel materials.
Second, the shaft processing process
The main process of rotating shaft machining is:
Rotary shaft forging inspection and cutting test, rotary shaft turning sequence machining, rotary shaft milling processing and rotary shaft boring sequence processing.
1. Rotary shaft forging inspection and cutting
After the rotating shaft forgings are put into the factory, the inspection shall be carried out in strict accordance with the design drawings and relevant technical specifications. All the information provided by the supplier must be complete, and the unsatisfactory forgings cannot be put into the process of cutting and processing, which is detrimental to the original condition.
First clean the surface of the forging and the center hole with a washing oil (kerosene), cotton yarn, white cloth, etc. Check the center hole with a sniffer, and the center hole should meet the drawing requirements. Then, the order specification is required to perform ultrasonic flaw detection on the outer circular surface and other parts. And an excessive portion of the journal portion, each of the inner fillets magnetic particle flaw detection inspection and surface hardness. After all the above items have passed the inspection, the 350t heavy-duty CNC bed is turned on the rotating shaft forgings. Check the shape tolerance and machining allowance of each part of the forging. After passing the test, cut the test ring according to the drawings and technical specifications.
2. Rotary shaft turning sequence processing technology
The machining of the rotating axle sequence is carried out on a heavy-duty 350t heavy duty CNC sleeper. At present, the conventional process for machining the rotating shaft of a steam (gas) wheel generator is: Universal joint - double bracket support. That is, the torque is transmitted by the universal joint, and the center frame is supported by the rotating shaft steam, the excitation journal or the oil sling. The use of this processing technology can well solve the negative impact on the machining accuracy due to factors such as the gap of the machine's own transmission mechanism.
3. Rotary shaft milling processing technology
The milling process of the lower slot is to use a disc milling cutter for rough milling and semi-finishing milling to lower the slot, and to finish the lower slot with a rod milling cutter. The numerical control indexing accuracy of the device is used to ensure the indexing accuracy of the lower wire slot.
Turbine generator rotor slots have been machined using machine clamp welded rotor milling cutters. Due to the long grinding time of the milling cutter and the short milling time of the rotor milling machine, the tool preparation is not connected, and the machine tool often fails to work, which cannot meet the production needs. In recent years, the machine clamp indexable rotor roughing cutter and high speed steel integral milling cutter have been adopted. The indexable rotor milling cutter is adopted to improve the production efficiency and ensure the processing quality of the rotor groove.
4. Rotary shaft boring sequence machining process
The coupling boring mold is installed, and the boring mold is assembled with the inner end of the coupling end face. The model "A" mark is placed at the position where the mark "G" on the outer circle is symmetrical when the coupling is placed on the lathe. After the assembly, it is required that the feeler of the 0.02 mm joint surface is not entered, and then the main shaft of the boring machine is found by the boring hole. After the coaxiality is within 0.01mm, the coupling hole can be processed.
Such as shaft forging inspection and cutting test, turning sequence processing technology, milling processing technology, boring sequence processing technology. Used in the rotary shaft material has certain requirements. Let's introduce each of these contents separately.
First, the rotating shaft material
The large-capacity turbine rotor core is made of high-quality alloy steel forgings with high mechanical strength and good magnetic permeability (such as nickel-chromium molybdenum vanadium, nickel-chromium vanadium, vanadium-nickel-molybdenum, etc.). For large steam turbine generators of thermal power stations, such motor shafts requiring load changes and frequent start and stop during operation, most of the large and large steam turbine generator rotor shafts at home and abroad use NiCrMoV steel materials.
Second, the shaft processing process
The main process of rotating shaft machining is:
Rotary shaft forging inspection and cutting test, rotary shaft turning sequence machining, rotary shaft milling processing and rotary shaft boring sequence processing.
1. Rotary shaft forging inspection and cutting
After the rotating shaft forgings are put into the factory, the inspection shall be carried out in strict accordance with the design drawings and relevant technical specifications. All the information provided by the supplier must be complete, and the unsatisfactory forgings cannot be put into the process of cutting and processing, which is detrimental to the original condition.
First clean the surface of the forging and the center hole with a washing oil (kerosene), cotton yarn, white cloth, etc. Check the center hole with a sniffer, and the center hole should meet the drawing requirements. Then, the order specification is required to perform ultrasonic flaw detection on the outer circular surface and other parts. And an excessive portion of the journal portion, each of the inner fillets magnetic particle flaw detection inspection and surface hardness. After all the above items have passed the inspection, the 350t heavy-duty CNC bed is turned on the rotating shaft forgings. Check the shape tolerance and machining allowance of each part of the forging. After passing the test, cut the test ring according to the drawings and technical specifications.
2. Rotary shaft turning sequence processing technology
The machining of the rotating axle sequence is carried out on a heavy-duty 350t heavy duty CNC sleeper. At present, the conventional process for machining the rotating shaft of a steam (gas) wheel generator is: Universal joint - double bracket support. That is, the torque is transmitted by the universal joint, and the center frame is supported by the rotating shaft steam, the excitation journal or the oil sling. The use of this processing technology can well solve the negative impact on the machining accuracy due to factors such as the gap of the machine's own transmission mechanism.
3. Rotary shaft milling processing technology
The milling process of the lower slot is to use a disc milling cutter for rough milling and semi-finishing milling to lower the slot, and to finish the lower slot with a rod milling cutter. The numerical control indexing accuracy of the device is used to ensure the indexing accuracy of the lower wire slot.
Turbine generator rotor slots have been machined using machine clamp welded rotor milling cutters. Due to the long grinding time of the milling cutter and the short milling time of the rotor milling machine, the tool preparation is not connected, and the machine tool often fails to work, which cannot meet the production needs. In recent years, the machine clamp indexable rotor roughing cutter and high speed steel integral milling cutter have been adopted. The indexable rotor milling cutter is adopted to improve the production efficiency and ensure the processing quality of the rotor groove.
4. Rotary shaft boring sequence machining process
The coupling boring mold is installed, and the boring mold is assembled with the inner end of the coupling end face. The model "A" mark is placed at the position where the mark "G" on the outer circle is symmetrical when the coupling is placed on the lathe. After the assembly, it is required that the feeler of the 0.02 mm joint surface is not entered, and then the main shaft of the boring machine is found by the boring hole. After the coaxiality is within 0.01mm, the coupling hole can be processed.
