JB/T 7027-1993 Technical requirements for 300～600MW steam turbine rotor forgings
Some standard content:
Machinery Industry Standard of the People's Republic of China
JB/T7027-93
300～600MW Steam Turbine
Technical Conditions for Rotor Forgings
1993-09-21 Issued
Ministry of Machinery Industry of the People's Republic of China
Implementation on 1994-07-01
Machinery Industry Standard of the People's Republic of China
300600MW Steam Turbine
Technical Conditions for Rotor Forgings
1 Subject Content and Scope of Application
JB/T 7027 --93
This standard specifies the technical requirements, inspection rules, test methods, certificates and marks of vacuum-treated alloy steel forgings for 300～600MW steam turbine rotors.
This standard applies to the ordering, manufacturing and inspection of rotor forgings for 300-600MW steam turbines working under high temperature and (or) high stress.
2 Reference standards
GB2106
GB6394
GB6395
GB6397
GB10561
ZBJ32.005
JB/ZQ6101
JB/ZQ6104
JB/ZQ6117
3 Ordering requirements
Chemical analysis methods for copper, iron and alloys
Jinchen tensile test method
Metal Brinell hardness test method
Metal Charpy ( V-notch) impact test methodMethod for determining average grain size of metals
Method for high temperature tensile endurance test of metals
Metal tensile test specimen
Microscopic evaluation method for non-metallic inclusions in steelTest method for thermal stability of steam turbine main shaft and rotor forgingsPowder avoidance inspection method for forged steel parts
Ultrasonic flaw detection method for steam turbine and generator rotor forgingsMethod for testing mechanical properties of steel products
3.1 The purchaser shall specify the adopted standard, sales number, corresponding technical requirements, inspection items and inspection items other than those required by this standard in the order contract or technical agreement.
3.2 The purchaser shall provide the silver parts ordering drawings indicating the sampling positions for mechanical properties tests and the deep finishing dimensions of blade slots.3.3 The items that the purchaser requires to participate in on-site inspection shall be stated in the contract. 4 Technical requirements
4.f Manufacturing process
4.1.1 Smelting and casting
4.1.1.1 The steel for silver parts shall be smelted by ladle refining or electroslag remelting. With the consent of the purchaser, other methods of smelting that ensure quality may also be used. 4.1.1.2 The molten steel shall be vacuum treated during pouring to remove harmful gases, especially hydrogen. During the vacuum treatment process, the capacity of the vacuum system must be large enough to reduce the initial increased pressure to a low value within 2 minutes after porcelain opening, which should usually be lower than 133Pa. 4.1.2 Plating
4.1.2.1 There shall be sufficient removal of the upper and lower parts of the copper chain to ensure that the finished forgings are free of shrinkage cavities, sparseness, severe segregation and other harmful defects.
Approved by the Ministry of Machinery Industry on September 21, 1993
Implemented on July 1, 1994
JB/T7027-93
4.1.2.2 The forging method used must make the entire part as uniform as possible. The forging press should have sufficient tonnage to forge the entire cut surface of the forging. The axis of the forging should roughly coincide with the center line of the ingot. Unless otherwise specified in the order agreement, the better end of the ingot should be the end close to the generator.
4.1.2.3 The steel ingot can be forged into a rotor by forging or direct forging. If the forging process is adopted, the steel ingot should be lengthened before forging. The axial length should be reduced by at least 30% during forging. If the direct forging method is adopted, the ratio of the cross-sectional area of the steel ingot and the rotor at the maximum diameter should be greater than 2.75:1 for 30Cr1Mo1VE steel forgings and greater than 3.5+1 for 30Cr2Ni4MoVE steel plated parts. The above requirements are excluding electroslag ingots. 4.1.3 Heat treatment
4.1.3.1 Heat treatment after forging
30Cr1Mo1VE steel forgings shall be subjected to at least one normalizing treatment at 980-1030℃, tempered after normalizing, and then air-cooled or furnace-cooled. 30Cr2Ni4MoVE steel forgings shall be subjected to at least two normalizing treatments at different temperatures within the range of 835-1010℃, kept for a long enough time under the normalizing method to ensure the austenitization and homogenization of the structure, cooled to below the transformation temperature, and then tempered, furnace-cooled or air-cooled after tempering.
4.1.3.2 Performance heat treatment
After rough machining, the forgings shall be subjected to performance heat treatment in the straightened state. 30Cr1Mo1VE steel forgings should be uniformly heated to 940-970℃, and after being kept warm for a long enough time, the shaft surface should be evenly cooled to below 205℃ by blasting, and then slow cooling is allowed. Oil or water spray cooling can only be used with the consent of the buyer. After obtaining a good phase change structure, the forgings should be tempered at no less than 660℃, kept warm for a long enough time, and then furnace cooled to below 300℃, and then allowed to be air-cooled out of the furnace. 30Cr2Ni4MoVE steel forgings should be uniformly heated to 830-860℃, and water or water spray tempered after sufficient insulation. After obtaining a good phase change structure, they should be tempered at no less than 570℃. Keep warm for a long enough time, then furnace cooled to below 300℃, and then allowed to be air-cooled out of the furnace.
4.1.3.3 Stress Relief Treatment
After the performance heat treatment and subsequent rough machining and center hole drilling, the forgings shall be stress relieved within the range of 15-50℃ below the final tempering temperature, but the stress relief temperature of 30Cr1Mo1VE steel forgings shall not be lower than 620C, and the stress relief temperature of 30Cr2Ni4MoVE steel shall not be lower than 540℃.
Forgings shall be in a vertical state during stress relief treatment, heated evenly, and have sufficient holding time to ensure complete burn-through. The cooling rate of the forgings before cooling to 370℃ shall not exceed 15℃/h, and then furnace cooled to 170-230℃, and then air cooled out of the furnace. 4.1.3.4 With the consent of the purchaser, the stress relief treatment temperature may be higher than the range specified in Article 4.1.3.3 of this standard. At this time, the center hole test piece shall be returned to the original corresponding position. After stress relief treatment, additional tensile test must be carried out. 4.1.4 Machining
4.1.4.1 Before the performance heat treatment, the entire surface of the forging shall be subjected to the first rough machining. Without the consent of the buyer, it is not allowed to cut grooves between the integral impellers and process the impeller steps before the performance heat treatment and formal ultrasonic flaw detection. 4.1.4.2 After the performance heat treatment, the forging shall be subjected to the second rough machining before the stress relief treatment and thermal stability test, and the center hole shall be tested.
4.1.4.3 The center hole shall be drilled according to the size and tolerance specified in the purchaser's order sample. In order to remove the excessive defects in the center part detected by ultrasonic, it is allowed to enlarge the center hole within the limit range indicated in the order drawing or agreed by the purchaser. 4.1.4.4 After the stress relief treatment, the center hole shall be refined and polished or polished by a method that does not cover the defects, so that the surface roughness R value is 1.6μmbzxZ.net
4.1.4.5 During the manufacturing and subsequent packaging process, the rotor body forging shall not be welded. 4.2 Chemical composition
4.2.1 The supplier shall conduct smelting analysis for each heat of molten steel, and the analysis results shall comply with the requirements of Table 1. 2
30Cr1Mo1VE
30Cr2Ni4MoVF
30Cr1Mo1VE
30Cr2Ni4MoVE
Note: ① Strictly control the aluminum content in the steel, Mn
～~1. 00
JB/T7027-93
～ 0. 37
Chemical composition
≤0.0015
③ If the chemical composition exceeds the allowable value, the purchaser shall be notified in time for review. If the purchaser has not responded within 10 days after the written notice is issued, the forgings can continue to be processed. ③ Under the premise of meeting the requirements of mechanical properties, the carbon content of 30Cr2Ni4MoVE steel should be reduced as much as possible. ① When vacuum deoxidation is used, the silicon content should not exceed 0.10%. ③ The specified values of lead, copper and tin of 30Cr1Mo1VE pin and 30Cr2Ni4MoVE steel are the target values. 4. 2. 2
The supplier shall conduct finished product analysis for each forging: the analysis results shall comply with the provisions of Table 1, but the deviations specified in Table 2 are allowed. Table 2 Permissible deviations of chemical composition
30Cr1Mo1VE
30Cr2Ni4MoVE
30Cr1Mo1VE
30Cr2Ni4MoVE
+ 0,02
Each forging shall be analyzed for gas content, and the results shall comply with the provisions of Table 3. Table 3 Gas content
30Cr1Mo1VE
30Cr2Ni4MoVE
4.3 Mechanical properties
4.3.1 The conventional mechanical properties of forgings shall comply with the provisions of Table 4. At the same time, the difference between the maximum and minimum values of the radial test specimen of the rotor body shall not exceed 55MPa for 30Cr1Mo1VE steel; when the service strength of 30Cr2Ni4MoVE steel is less than or equal to 690MPa, the difference shall not exceed 55MPa. When it is greater than 690MPa, the difference shall not exceed 70MPa. 3
Upper flat white energy
Sampler position
Body radial, shaft end
Center hole (weaving direction)
Body radial, shaft end
Center hole (longitudinal)
Body radial, output end
Center hole (longitudinal)
Body radial, shaft end
Center hole (longitudinal)
Body radial, shaft end
Center hole (transverse)
Body radial, shaft end
Center hole (transverse)
Body radial
Center hole (transverse)
Body radial
Center hole (transverse)
JB/T 7027-93
Mechanical properties
590~690
≤116
30Cr1Mo1VE
≥690
≥660
790~910
≥760
860~970
30Cr2Ni4MoVE
When the first batch, process changes or special requirements are required, the high temperature endurance strength requirements of 30Cr1Mo1VE steel forgings are listed in Table 5, among which, 4.3.2
100h endurance strength index To ensure the value, 500h endurance strength index is used for assessment test. Table 5 High temperature endurance strength
Test requirements
Fracturing time ≥100h
Elongation ≥15%
Fracture shall not be on V-notch
Fracturing time ≥500h
When the first batch or harmful residual elements exceed the standard, 30Cr2Ni4MoVE steel forgings shall be assessed by aging test, and the results shall comply with the provisions of Table 6. Table 6 Aging test
Aging time
FATT, value-added
4.4 degree inspection
JB/T 702793
Check the uniformity of hardness of plated parts after performance heat treatment. The absolute value of hardness is for reference. The hardness difference between points on the same arc surface should not exceed 30HBS, and the hardness difference on the same line should not exceed 40HBS. 4.5 Nondestructive inspection
4.5.1 General requirements
Forgings shall not have cracks, white spots, shrinkage cavities, folds, excessive segregation, inclusions and looseness exceeding the allowable limit. 4.5.2 Magnetic particle inspection
The outer cylindrical surface of the forging shall be subjected to magnetic particle inspection after fine machining. The supplier shall ensure that the inspection results meet the following requirements: a. No defect display greater than 1.5 mm in length is allowed on the outer ring surface of the rotor body: b. During the final inspection of the rotor body, except for the bearing part, if a defect display greater than 1.5 mm is found in other parts that are allowed to be polished, local grinding and polishing are allowed. The depth of the polishing shall not exceed 1.6 mm, and it shall have a smooth transition with the surrounding surface. 4.5.3 Ultrasonic inspection
4.5.3.1 Single scattered defect signals with an equivalent diameter of less than 1.6 mm shall not be counted, but the noise height shall be less than 50% of the amplitude of the equivalent diameter of 1.6 mm.
Note: A single scattered defect refers to a defect where the distance between two adjacent defects is greater than 10 times the equivalent diameter of the larger defect. 4.5.3.2 The axial, radial and circumferential positions of all defects with an equivalent diameter of 1.6 to 3.5 mm shall be recorded and reported to the purchaser. The total number of defects with an equivalent diameter of 1.6 to 3.5 mm shall not exceed 20, and any defect with an equivalent diameter greater than 3.5 mm is not allowed. 4.5.3.3 Three dense defect areas with an equivalent diameter less than 1.6 mm are allowed outside 75 mm from the center hole surface, but the size of the dense area in any direction shall not be greater than 20 mm, and the distance between any two dense areas shall not be less than 120 mm. 4.5.3.4 When the bottom wave attenuation loss caused by the defect reaches 3 dB, it shall be recorded and reported to the purchaser. 4.5.3.5 No wandering signal or strip defect signal is allowed. 4.5.3.6 The supplier shall provide the buyer with the material loading and reduction data measured at the two ends and three places in the middle of the rotor body with 2~2.5MHz and 4~5MHz probes respectively.
4.5.3.7 When the ultrasonic flaw detection results of silver parts exceed the above provisions, the supplier and the buyer shall conduct re-inspection and discussion, but whether the forgings can be judged as qualified shall be decided by the buyer.
4.5.4 Center hole inspection
After the center hole is finely bored or ground to a surface roughness R. value of 1.6um, the center hole inspection shall be carried out and shall comply with the following provisions: a. The axial and circumferential positions of defects equal to or greater than 1.5mm shall be recorded and reported to the purchaser. Within a field of view inspected by a peephole instrument, there shall not be 3 visible defects greater than 1.5mm or 9 visible defects less than 1.5mm. b.
The total length of all defects on the same generatrix on the inner hole surface shall not be greater than 50mm; d.
No tear-like bifurcation defects are allowed: e.
When the distance between two defects on the same generatrix is less than 5 times the length of the larger defect, it shall be treated as a continuous defect; f.
Visible defects greater than 3mm in length and dense areas composed of non-metallic inclusions are not allowed: g. For defects that do not meet the above requirements, local grinding and polishing are allowed after obtaining the consent of the purchaser, but the depth of grinding and polishing should not exceed 1.6mm, and the transition should be smooth with the surrounding surface. 4.6 Thermal stability test
The purchaser shall conduct thermal stability test, and the supplier shall be responsible for the test results. 4.7 Metallographic inspection
4.7.1 The average grain size of forgings. 30Cr1Mo1VE steel should not be coarser than grade 2.0. 30Cr2Ni4MoVE steel should not be coarser than grade 3.0. 4.7.2 The four types of inclusions A, BC, and D of forgings should not exceed grade 3.0. 4.8 Residual stress inspection
The residual stress of the mirror parts shall be measured, and its value shall not be greater than 8% of the lower limit of radial yield strength in Table 4. If the residual stress exceeds the above provisions, the forgings shall still be supplemented with stress relief tempering in accordance with the provisions of Article 4.1.3.3 of this standard, and the residual stress and hardness values shall be re-measured. 5
4.9 Dimensions and surface roughness
JB/T7027-93
4.9.1 The plated parts after processing shall meet the requirements of dimensions, tolerances and surface roughness specified in the order letter. 4.9.2 The straightness tolerance of the center hole axis is 3mm; the roundness tolerance of the center hole is 0.3mm, and the coaxiality tolerance between the center hole and the forging is 1.0mm.
5 Inspection rules and test methods
5.1 Chemical composition analysis
5.1.1 Chemical composition analysis shall be carried out according to the method specified in GB223 or other methods that can ensure the quality of analysis. 5.1.2 Each furnace (each package) of molten steel can be sampled during pouring to determine the chemical composition of the molten steel. When multiple furnaces are poured together, the weighted average analysis results shall also be reported. When smelting analysis is not possible, finished product analysis is allowed to replace smelting analysis. When sampling is taken from forgings, the analysis results should meet the requirements of finished product analysis.
5.1.3 The finished product analysis sample can be taken from 1/2 of the wall thickness of each plated extension, and from 1/3 of the surface for forgings without center holes, or from radial performance acceptance samples.
5.1.4 The sample for gas analysis should be cut from the middle section of the core support and the radial test rod. 5.2 Mechanical property inspection
5.2.1 The tensile property inspection shall be carried out according to the method specified in JB/ZQ6117, and the impact test shall be carried out according to the method specified in GB2106. 5.2.2 Except for the shaft end sample, the notch direction of the impact sample shall be parallel to the axis of the rotor body. 5.2.3 The shaft end, radial and center hole test samples of the rotor body shall be cut according to the position and quantity specified in the purchaser's order drawing and sampling drawing. 5.2.4 The high temperature endurance strength test shall be carried out in accordance with the provisions of GB6395, and the sample specifications shall be provided by the purchaser. 5.2.5 The high temperature endurance strength test or long-term aging test shall be carried out by the purchaser, and the supplier shall ensure that the test results meet the requirements of Table 5 and Table 6. 5.3 Hardness test
Measure one point every 90* on the outer surface of the two journals and the shaft of each forging (a total of 12 points). 5.4 Non-destructive testing
5.4.1 The magnetic particle test of the outer surface shall be carried out in accordance with JB/ZQ6101. The ultrasonic test of the outer surface shall be carried out in accordance with JB/ZQ6104. The magnetic particle test and ultrasonic test of the center hole shall be carried out in accordance with the methods determined by both parties. 5.4.2 Ultrasonic testing should be carried out at least twice. The first test is carried out before quenching and tempering and drilling the center hole. The second test is carried out after quenching and tempering and before drilling the center hole. The results of both tests are provided to the buyer. The inner hole ultrasonic test is carried out by the buyer, and the supplier shall ensure that the center hole ultrasonic test results meet the requirements of the relevant provisions of this standard. 5.4.3” The center hole inspection is observed with a laparoscopic instrument, and if necessary, a magnetic particle inspection combined with a film inspection instrument is used for observation. 5.5 Metallographic inspection
5.5.1 Grain size inspection is carried out by sampling the radial end of the shaft motor and the middle of the center hole bar material in accordance with the provisions of GB6394. 5.5.2 Inclusion inspection is carried out by sampling the radial end of the shaft motor and the middle of the center hole material, and is evaluated according to the rating diagram 1 in Appendix A of GB10561.
5.6 Residual stress determination
5.6.1 The residual stress is determined by the ring cutting method or the ring core resistance strain method. 5.6.2 The ring cutting method is to cut a 25mm×25mm ring at one end of the shaft body, and use the method of measuring the average deformation of the ring before and after cutting to calculate the residual stress. The calculation formula is: o,E8/D
Where a, residual stress.MP a;
3-Algebraic value of diameter increase, mm:
D Outer diameter of the ring before cutting, mm:
E--Elastic modulus of the material, MPa
5.7 Thermal stability test
The thermal stability test shall be carried out in accordance with the provisions of ZBJ32005. 5.8 Retest
JB/T702793
5.8.1 If a test result in the mechanical property test is unqualified, two specimens can be taken from the same position of the forging as the original specimen for retest. The retest results of the two specimens of the tensile test and the average value of the three test results of the initial test and retest shall meet the specified requirements; the two specimens of the impact test and the average value of all test results shall meet the specified requirements. 5.8.2 If the mechanical property test fails due to white spots and cracks, it shall not be Retest. 5.9 Re-heat treatment
5.9.1 If the retest of mechanical properties of the forging still fails, when the strength of the specimen is high but the plasticity, toughness or brittle transition temperature does not meet the requirements, the center hole specimen should be reinserted into the hole and re-tempered together with the forging, and then inspected according to the provisions of Article 5.2 of this standard. The sampling location of the center hole specimen after re-tempering should be agreed upon with the purchaser. 5.9.2 If the mechanical properties test results show that the forging cannot be re-tempered, then how the forging is further heat treated and processed must be determined by negotiation between the supply and demand parties.
5.9.3 Re-heat treatment should not exceed two times. 6 Acceptance and certificate of conformity
6.1 The supplier shall provide the necessary convenience to the purchaser's acceptance personnel so that the purchaser's acceptance personnel can conduct on-site inspection. 6.2 The purchaser has the right to choose a certain part of the forging. For some acceptance test items, if it is found in the acceptance test or in the subsequent processing or test that the forgings do not meet the supplementary technical requirements specified in this standard and the order contract, the purchaser shall promptly notify the supplier and the two parties shall negotiate to resolve the problem. 6.3 The supplier shall provide the purchaser with a certificate of conformity, which shall include the following: a.
He Shang number:
Forging drawing number:
Standard number and steel type;
Smelting furnace number and smelting method:
Smelting analysis and finished product analysis results:
Main dimensions of steel ingots and actual forging ratio of forgings; Actual temperature, holding time and cooling method of each heat treatment: Test results of mechanical properties;
Ultrasonic test report:
Results of other tests and supplementary tests required by the purchaser: Actual dimensions and weight of delivered forgings.
Marking and Packaging
The supplier shall mark the contract number, furnace number, part number, etc. on each silver piece corresponding to the lower end face of the steel ingot, and paint it with white paint. 7.1
7.2 The plated piece shall be marked with the ultrasonic circumferential start mark. 7.3 The supplier shall apply rust inhibitor to the outer surface and center hole surface of each forging, and plug the two ends of the center hole with wooden plugs to prevent damage or corrosion during transportation and storage.
Additional Notes:
This standard was proposed and coordinated by the Deyang Large Castings and Forgings Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Deyang Large Castings and Forgings Research Institute. The main drafters of this standard are Lu Jirong, Sun Qiyuan, Wang Jigen, and Zhou Yunsong. 7
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