JB/T 8707-1998 Technical requirements for rotor forgings without center hole for steam turbines above 300MW
Some standard content:
ICS77. 140.85
Machinery Industry Standard of the People's Republic of China
JB/T8707-1998
300MW and above steam turbine
Specification of the noncentral hole rotors forgingsusedfor more than30oMW turbine generator1998-03-19 Issued
Ministry of Machinery Industry of the People's Republic of China
1998-07-01 Implementation
JB/T8707—1998
Appendix A of this standard is a reminder appendix.
This standard is proposed and managed by Deyang Large Castings and Forgings Research Institute of the Ministry of Machinery Industry. Drafting unit of this standard: Shanghai Steam Turbine Co., Ltd. Main drafters of this standard: Wang Siyu and Wang Jigen. 1
1Scope
Standard of the Machinery Industry of the People's Republic of China
Technical Conditions of the Non-Central Hole Rotor Forgings Used For than 300MW Turbine Generator
Specification of the noncentral hole rotors forgings used for more than 300MW turbine generator JB/T8707-1998
This standard specifies the technical requirements, inspection rules, test methods, certificates and marks of vacuum-treated alloy steel forgings for non-central hole rotors used for steam turbines with a capacity of more than 300MW (including 300MW). This standard is applicable to the ordering, manufacturing and inspection of non-central hole rotor forgings for steam turbines with a capacity of more than 300MW (including 300MW) working under high temperature and (or) high stress.
2Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are all valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest version of the following standards. GB223—(82~94)
GB231—84
GB/T229—94
GB6394-—86
GB6395—86
GB10561—89
JB/T702793
JB/T846896
ZBJ32005—88
ASTMA370—77
3Ordering requirements
Chemical analysis methods for steel and alloys
Metal Brinell hardness Test methods
Metal Charpy notch impact test method
Metal average grain size determination method
Metal high temperature tensile rupture test method
Microscopic evaluation method of non-metallic inclusions in steel300600MW steam turbine rotor forgings technical conditionsMagnetic particle inspection method for forged steel parts
Thermal stability test method for steam turbine main shaft and rotor forgingsMethod for mechanical properties test of steel products
3.1 The supplier shall have a complete quality assurance system and have a track record of producing sufficient quantities of similar materials and similar size rotor forgings with center holes.
3.2 The purchaser shall specify the forging drawing number, adopted standard, steel grade, strength grade and inspection items and indicators other than the requirements of this standard in the order contract or technical agreement.
3.3 The purchaser shall provide the forging order drawing indicating the sampling position for mechanical properties test and the deep finishing dimensions of the blade root groove. 3.4 The items that the purchaser requires to participate in on-site inspection shall be stated in the contract. Approved by the Ministry of Machinery Industry on March 19, 1998
Implemented on July 1, 1998
4 Technical requirements
4.1 Manufacturing process
JB/T8707-1998
The rotor without center hole shall be manufactured according to the mature hot processing process of the corresponding rotor with hole. In case of major changes, the purchaser's consent shall be obtained. 4.1.1 Smelting and casting
4.1.1.1 The steel for forgings 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, the capacity of the vacuum system must be large enough to reduce the initial increased pressure to a low value within 2 minutes after pouring, which should usually be less than 133Pa.4.1.2 Forging
4.1.2.1 Sufficient removal should be made on both the upper and lower parts of the ingot to ensure that the finished forgings are free of shrinkage, looseness, severe segregation and other harmful defects.
4.1.2.2 The forging method used must give the entire forging a uniform structure. The forging press should have sufficient tonnage to forge the entire cross section 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 ingot can be upset or directly forged into a rotor. If the upset process is used, the ingot should be lengthened before upsetting, and the axial length should be reduced by at least 30% during upsetting. If the direct forging method is adopted, the ratio of the cross-sectional area of the ingot and the maximum diameter of the rotor shall be greater than 2.75:1 for 30Cr1MoIV steel forgings and greater than 3.5:1 for 30C2Ni4MoV steel forgings. The above requirements are excepted for electroslag ingots. 4.1.3 Heat treatment
4.1.3.1 Heat treatment after forging
30Cr1Mo1V steel forgings shall be normalized at 980～1030℃ at least once, tempered after normalizing, and then air-cooled or furnace-cooled. 30Cr2Ni4MoV steel forgings shall be normalized at different temperatures in the range of 835～1010℃ for no less than two times, kept at the normalizing temperature for a long enough time 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 should be subjected to performance heat treatment in a vertical state. 30Cr1Mo1V steel forgings should be uniformly heated to 940-970℃, and after being kept warm for a long enough time, the shaft surface should be cooled to below 205℃ by uniform blasting, and then slow cooling is allowed. Oil quenching or water spray cooling can only be used with the written consent of the purchaser. After obtaining a good phase transformation 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.
30Cr2Ni4MoV steel forgings should be uniformly heated to 830-860℃, and after being fully kept warm, water quenched or water spray quenched. After obtaining a good phase transformation structure, they should be tempered at no less than 570℃, 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.
4.1.3.3 Stress Relief Treatment
After the performance heat treatment and subsequent rough machining, the forgings shall be stress relieved within the range of 15-50℃ below the final tempering temperature, but the stress relief temperature of 30Cr1Mo1V steel forgings shall not be lower than 620℃, and the stress relief temperature of 30Cr2Ni4MoV 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 4.1.3.3. After stress relief treatment, a supplementary tensile test must be carried out.
JB/T8707-1998
4.1.3.5 With the consent of the purchaser, stress relief treatment may not be performed. 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 purchaser, 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. 4.1.4.3 After all performance and ultrasonic flaw detection are qualified, the forging shall be processed according to the dimensional tolerance specified in the purchaser's order drawing. 4.1.4.4 During the manufacturing and subsequent packaging process, the rotor body forging shall not be welded.2 Chemical composition
The supplier shall conduct smelting analysis on each heat of molten steel, and the analysis results shall comply with the provisions of Table 1. Table 1 Chemical composition
30CrIMo1V
30Cr2N4MoV
1Strictly control the aluminum content in the steel.
2On the premise that the mechanical properties meet the requirements, reduce the carbon content of 30Cr2Ni4MbV steel as much as possible. 3When vacuum carbon deoxidation is adopted, the silicon content shall not exceed 0.10%430G1MbIV steel and the aluminum, copper and antimony specified values of 30G2Ni4MoV steel are the target valuesAl
4.2.2The supplier shall conduct finished product analysis on each forging, and the analysis results shall comply with the provisions of Table 1, but the deviation specified in Table 2 is allowed. Table 2 Allowable deviation of chemical composition
30G:1MolV
30C2Ni4MoV
30GIMolV
30C2Ni4MbV
Each forging shall be analyzed for gas content, and the results shall conform to the requirements of Table 3. Table 3 Gas content
30GIMolV
30C2Ni4MbV
Mechanical properties
≤1.0X106
≤1.5×106
≤35×10-6
≤35×106
≤100×106
≤70×10%
JB/T8707-1998
4.3.1 The conventional mechanical properties of forgings shall conform to the requirements of Table 4. At the same time, the difference between the maximum and minimum values of the yield strength of the rotor body specimen in the longitudinal direction should not be greater than 55MPa for 30Cr1Mo1V steel and should not be greater than 70MPa for 30Cr2Ni4MoV steel. Table 4 Mechanical properties
FATTso
Upper platform energy J
First batch production,
Sampling position
Body radial, shaft end
Body radial, shaft end
Body radial, shaft end
Body radial, shaft end
Body radial
Body radial
590~690
≥720
≤116
30CrIMoIV
Forging strength grade
790~910
30Cr2N4MoV
860970
When the process changes significantly or there are special requirements, the high temperature endurance strength requirements of 30CrlMolV steel forgings are listed in Table 5. Among them, the 100h endurance strength index is the assessment value, and the 5000h endurance strength index is the guaranteed value. Table 5 High temperature endurance strength
Test requirements
Fracture time ≥100h
Elongation ≥15%
Fracture shall not be at the V-notch
Fracture time ≥5000h
4.3.3 When the first batch of production or harmful residual elements exceed the standard, the aging test and acceptance indicators of 30Cr2Ni4MoV steel forgings shall be agreed upon by the supply and demand parties.
Hardness test
The uniformity of hardness of forgings shall be checked after performance heat treatment, and the absolute value of hardness is for reference. The hardness difference between points on the same arc surface shall not exceed 30HBS, and the hardness difference on the same busbar shall not exceed 40HBS. 4.5 Nondestructive Inspection
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
Forgings shall be subjected to magnetic particle inspection after finishing, and the supplier shall ensure that the inspection results meet the following requirements: a) No defects greater than 1.5 mm in length shall be allowed on the outer surface of the rotor body; b) During the final inspection of the rotor body, except for the bearing part, if defects greater than 1.5 mm are found in other grinding parts that are allowed to be polished, local grinding and polishing are allowed, and the polishing depth shall not exceed 1.6 mm, and shall have a smooth transition with the surrounding surface. 4
4.5.3 Ultrasonic inspection
JB/T8707-1998
4.5.3.1 Single scattered defect signals with an equivalent diameter of less than 1.6 mm1) shall not be counted, but the noise height shall be less than 50% of the amplitude of the equivalent diameter of 1.6 mm
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. 4.53.3 For 30Cr1MolV steel forgings, 30Cr2N4MoV steel forgings, 150mm from the axis, and 170mm from the axis, 30Cr2N4MoV steel forgings are allowed to have 3 dense defect areas with an equivalent diameter of less than 1.6mm, but the size of the dense area in any direction should not be greater than 20mm, and the distance between any two dense areas should not be less than 120mm. 4.5.3.4 When the bottom wave attenuation loss caused by defects reaches 3dB, it shall be recorded and reported to the buyer. 4.5.3.5 No wandering signal and strip defect signal are allowed. 4.5.3.6 The supplier shall provide the buyer with the material attenuation data measured at the two ends and the middle of the maximum diameter of the rotor body using 2~2.5MHz and 4~5MHZ probes.
4.5.3.7 When the ultrasonic flaw detection results of the forgings exceed the above provisions, the supplier and the buyer shall conduct re-inspection and discussion, but whether the forgings can be judged to be qualified shall be decided by the buyer.
4.5.3.8 When ultrasonic testing finds echo signals reaching the record level, whether the forging can be judged as qualified shall be determined by the purchaser. 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 shall not be coarser than Grade 2.0 for 30Cr1Mo1V steel and Grade 3.0 for 30Cr2N4MoV steel. 4.7.2 The four types of inclusions A, B, C, and D of forgings shall not exceed Grade 3.0. 4.8 Residual stress test
The residual stress of forgings 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 4.1.3.3, and the residual stress and hardness values shall be re-measured. 4.9 Dimensions and surface roughness
The processed forgings shall meet the requirements of dimensions, tolerances and surface roughness specified in the order drawings. 5 Inspection rules and test methods
5.1 Chemical composition analysis
5.1.1 Chemical composition analysis shall be carried out in accordance with the methods 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 shall meet the requirements of finished product analysis.
5.1.3 The finished product analysis sample can be taken from the same part of the longitudinal or radial sample of the forging. 5.1.4 The sample for gas analysis shall be cut from the radial test bar. 5.2 Mechanical property inspection
1) A single scattered defect is a defect in which the distance between two adjacent defects is greater than 10 times the equivalent diameter of the larger defect. 5
JB/T8707-1998
5.2.1 The tensile property test shall be carried out in accordance with the method specified in ASTMA370, and the impact test shall be carried out in accordance with the method specified in GB/T229. 5.2.2 Except for the shaft end specimen, the notch direction of the impact specimen shall be parallel to the axis of the rotor body. 5.2.3 The shaft end and radial specimens of the rotor body shall be cut according to the position and quantity specified in the order drawing and sampling drawing of the purchaser. 5.2.4 The high temperature endurance strength test shall be carried out at the purchaser in accordance with the provisions of GB6395, and the supplier shall ensure that the test results meet the requirements of Table 5. 5.25 When necessary, the aging test shall be carried out at the purchaser, using the isothermal or step cooling test method. The supplier shall ensure that the test results meet the requirements of 4.3.3.
5.3 Hardness test
Measure one point every 90° on the outer cylindrical surface of the two journals and the shaft body of each forging (a total of 12 points). Hardness test is in accordance with GB231. 5.4 Nondestructive testing
5.4.1 General requirements
Forgings shall not have cracks, white spots, shrinkage cavities, folds, excessive segregation, inclusions and looseness exceeding the allowable limit. 5.4.2 Magnetic particle inspection
Forgings shall be subjected to magnetic particle inspection after finishing. The supplier shall ensure that the inspection results meet the following requirements: a) No defects greater than 1.5 mm in length are allowed on the outer surface of the rotor body; b) During the final inspection of the rotor body, except for the bearing part, if defects greater than 1.5 mm are found in other parts that are allowed to be polished, local grinding and polishing are allowed. The polishing depth should not exceed 1.6 mm, and it should have a smooth transition with the surrounding surface. 5.4.3 Ultrasonic testing shall be conducted at least twice, the first test shall be conducted before quenching and tempering, and the second test shall be conducted after quenching and tempering. The results of both tests shall be provided to the purchaser.
Ultrasonic testing shall be conducted in accordance with the method specified in Appendix A (suggested Appendix) or JB/T7027, or in accordance with the method agreed upon by the supply and demand parties. 5.5 Metallographic testing
5.5.1 Grain size testing shall be conducted by sampling the shaft body and in accordance with the provisions of GB6394. 5.5.2 Inclusion testing shall be conducted by sampling the shaft body and evaluating the inclusions according to the rating diagram I in Appendix A of GB10561-89. 5.6 Residual stress determination
5.6.1 Residual stress shall be 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 calculate the residual stress by measuring the average deformation of the ring before and after cutting. The calculation formula is:
Where: 0 residual stress, MPa:
5 algebraic value of diameter increment, 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
5.&1 If a test result in the mechanical property test is unqualified, two specimens can be taken from the adjacent parts of the forging to be retested. 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. 6
JB/T8707-1998
5.8.2 If the mechanical properties test fails due to white spots and cracks, retesting is not allowed. 5.9 Reheat treatment
5.9.1 If the mechanical properties of the forgings are still unqualified after retesting, when the strength of the specimen is high but the plasticity, toughness or brittle transition temperature does not meet the requirements, the forgings should be re-tempered and then tested according to the provisions of 5.2. 5.9.2 If the mechanical properties test results show that the forgings cannot be re-tempered, then how to further heat treat and process the forgings must be determined by negotiation between the supplier and the buyer.
5.9.3 Re-quenching and tempering heat treatment should not exceed 2 times. 6 Acceptance and certificate of conformity
6.1 The supplier shall provide the necessary convenience to the buyer's acceptance personnel so that the buyer's acceptance personnel can conduct on-site inspections. 6.2 The purchaser has the right to select certain acceptance test items for forgings. 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 issue. 6.3 During the production process, if either party deems it necessary to conduct rotor core performance verification, the two parties shall negotiate to resolve the issue. 6.4 The supplier shall provide the purchaser with a certificate of conformity, which shall include the following: a) Contract number:
b) Forging drawing number:
c) Standard number and steel type:
d) Melting furnace number and melting method:
e) Forging identification number:
J Melting analysis and finished product analysis results;
g) Main dimensions of steel ingot and actual forging ratio of forgings; h) Actual temperature, holding time and cooling method of each heat treatment; i) Test results of mechanical properties:
i) Ultrasonic test report:
k) Results of other tests and supplementary tests required by the purchaser: 1) Actual dimensions and weight of delivered forgings. 7 Marking and packaging
7.1 The supplier shall mark each forging with the contract number, furnace number, part number, etc. corresponding to the lower end face of the steel ingot, and circle it with white paint. 7.2 Forgings shall be marked with ultrasonic flaw detection circumferential start marks 7.3 The supplier shall apply rust inhibitor to the surface of each forging to prevent damage or corrosion during transportation and storage. 7
A1 Forging preparation
Al.1 Testing timing
JB/T8707-1998
Appendix A
(Suggested appendix)
Ultrasonic flaw detection method
Formal ultrasonic flaw detection of forgings shall be carried out after mechanical property heat treatment (quenching and tempering) and processing according to the requirements of the flaw detection drawing. A1.2 Processing requirements of forgings
Machining for ultrasonic flaw detection shall make the rotor forging have a simple geometric shape (cylinder), and the transition between different diameters shall be at right angles.
Machining drawings for flaw detection drawn by the contracting plant shall be approved by the technical department and quality inspection department of the ordering plant. The roughness of the flaw detection surface R≤6.3um.
A1.3 Forging state
During flaw detection, the geometric shape, size and surface roughness of the forging must meet the requirements of the mechanical processing drawings for flaw detection. The surface of the flaw detection part should be free of scratches, chips left by machining, paint or other foreign adhesions. A2 Ultrasonic flaw detection equipment
A21 The ultrasonic flaw detector should have at least three frequencies of 1.5MHz, 2.5MHz, and 5MHz or other frequencies with similar values. A2.2 Scanning linearity and vertical linearity
Measured according to ZBJ04001-87 "Test Method for Working Performance of Type A Pulse Reflection Ultrasonic Flaw Detection System". The scanning linearity error should not be greater than 2%.
The vertical linearity error should not be greater than 5%www.bzxz.net
A23 Attenuator or gainer
The adjustable attenuation or gain range is not less than 80dB, and each level is not greater than 2dB and can be continuously adjusted. The accuracy of the attenuator or gainer is ±1dB for any adjacent 12dB level. A24 Probe
The probe echo frequency shall be measured according to ZBY231-84 "Performance Test Method for Ultrasonic Flaw Detection Probes" and shall not be greater than ±10% of the standard frequency. The deviation of the axis of the straight probe sound beam from the normal shall not be greater than ±1°. A25 The system sensitivity of the ultrasonic flaw detector, probe and cable combination shall meet the scanning sensitivity requirements. A3 Coupling agent
Clean No. 30 engine oil or engine oil of equivalent viscosity. The same coupling agent must be used when flaw detection and flaw detection sensitivity correction. A4 Implementation of flaw detection
A4.1 Scanning direction
The scanning requirements for the entire rotor forging are shown in Figure A1a) and Table Al. A4.1.1 Longitudinal wave straight beam, see Figure Alb), Figure Alc); A4.1.2 Longitudinal wave oblique beam, see Figure Ald)
A4.1.3 Split probe longitudinal wave straight beam, see Figure Ale); A4.1.4 Shear wave oblique beam, see Figure Alf), Figure Alg). 8
bAl scanning
JB/T8707-1998
ALAJBIC
Rotor scanning tips
DB scanning chapter
A8 scanning
eC scanning pot
Scanning area of various probes
Verification symbol
a=14°
a=21°
a=28°
β-35 °
β=60°
B=35°
β=45°
A4.2 Inspection frequency
JB/T8707-1998
g) Scanning
Figure Al (end)
Table A1 Requirements for ultrasonic flaw detection scanning of rotor forgings The direction of incident sound wave
is biased towards the radial direction, and the angle of intersection with the radial direction is a
is oblique to the circumferential direction, and the angle of intersection with the radial direction is t The angle is B
oblique axial direction, and the intersection angle with the rotor transverse
section is β
Detection surface
Entire length cylindrical surface
Entire end plane
Entire length cylindrical surface
Entire length cylindrical surface
Entire length cylindrical surface, respectively, make oblique circumferential scans in clockwise and counterclockwise directions
Cylindrical surfaces of different diameters on both sides of the intersection of different diameters, and check the intersection. (
The frequency of various probes used for scanning can be 2 to 4MHz.) Make oblique axial scanning
Detection area
Figure A1b)
Figure Alc)
Figure Ald)
Figure Ale)
Figure Af)
Figure Alg)
When different flaw detection results are obtained due to the use of probes with different frequencies, the one that best describes the flaw detection results shall prevail. A4.3 Determine the flaw detection sensitivity
A43.1 Longitudinal wave straight beam probe
The echo height of the equivalent reflector of the Φ1.6 flat bottom hole at the center of the rotor forging reaches 20% of the height of the oscilloscope screen as the reference height. For probes with AVG curves, the AVG curve provided by the probe manufacturer can be used to obtain the required sensitivity data-the bottom wave height gain value.
For probes without AVG curves, the bottom wave height gain value B can be obtained by calculation. a) The sensitivity required for the defect echo height near the bottom of the workpiece to reach the recording level: B-20 log2AD6 The echo height of the equivalent reflector of the flat bottom hole reaches 20% of the height of the oscilloscope screen as the reference height. For probes with AVG curves, the AVG curve provided by the probe manufacturer can be used to obtain the required sensitivity data - the bottom wave height gain value.
For probes without AVG curves, the bottom wave height gain value B can be obtained by calculation. a) The echo height of the defect near the bottom of the workpiece reaches the sensitivity required for the recording level: B-20 log2AD
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