JB/T 7022-1993 Technical requirements for industrial steam turbine rotor forgings
Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T7022-1993
Industrial Steam Turbine Rotor Forgings
Technical Conditions
Published on September 21, 1993
Ministry of Machinery Industry of the People's Republic of China
Implemented on July 1, 1994
Mechanical Industry Standard of the People's Republic of China
Industrial Steam Turbine Rotor Forgings
Technical Conditions
Subject Content and Scope of Application
JB/T7022-1993
This standard specifies the technical requirements, inspection rules, test methods, certificates and marks of vacuum-treated alloy forgings of industrial steam turbine rotors.
This standard applies to the ordering, manufacturing and inspection of industrial steam turbine rotor forgings. Cited standards
GB2106
GB6394
GB6395
GB 6397
GB10561
JB1581
ZBJ32005
JB/ZQ6101
3Ordering requirements
Sampling method for chemical analysis of steel and allowable deviation of chemical composition of finished productsChemical analysis methods for steel and alloys
Metal tensile test method
Metal Charpy (U-notch) impact test methodMetal Brinell hardness test method
Metal Charpy (V-notch) impact test methodMethod for determining average grain size of metals
Metal high-temperature tensile test method Elongation test method
Metal tensile test specimen
Microscopic evaluation method of non-metallic inclusions in steelUltrasonic flaw detection method for turbine and turbogenerator rotors and main shaftsTest method for thermal stability of turbine main shaft and rotor forgingsMagnetic particle inspection method for forged steel parts
3.1 The purchaser shall specify the adopted standard, steel grade, service strength of forgings, corresponding technical requirements, inspection items and inspection items other than the requirements of this standard in the order contract or order agreement.3.2 The purchaser shall provide the order drawing of forgings indicating the sampling position of mechanical properties test and the finishing size of blade root groove depth.4 Technical requirements
4.1 Manufacturing process
4.1.1 Smelting
4.1.1.1 Steel ingots for forgings shall be smelted in electric furnaces and vacuum treated or ladle refined.4.1.1.2 With the consent of the purchaser, other smelting methods that can ensure the requirements of this standard are allowed. 4.1.1.3 High-quality raw materials should be used to ensure that the content of various inclusions in the forgings is as low as possible. 4.1.2 Forging
4.1.2.1 The steel ingots used for forging should have sufficient removal to ensure that the finished forgings have no shrinkage cavities and unacceptable segregation. 4.1.2.2 The forging equipment should have sufficient capacity to ensure that the entire cross-section of the forging is forged through. The entire cross-section should be fully deformed during forging, and the supplier should adopt forging and heat treatment methods that ensure uniform organization and fine grains of the forgings. Approved by the Ministry of Machinery Industry on September 21, 1993
Implementation on July 1, 1994
JB/T70221993
The end of the steel ingot with better quality should be the transmission (coupling) end. The axis of the forging should roughly coincide with the center line of the steel ingot. 4.1.2.3
4.1.3 Heat treatment
4.1.3.1 Forgings need to be normalized or annealed after forging. 4.1.3.2 Performance heat treatment of forgings should be carried out after rough machining. 4.1.3.3 Forgings should be hung vertically for heating and cooling during performance heat treatment. Strictly control the furnace temperature and sufficient holding time to obtain uniform and consistent mechanical properties. bzxz.net
4.1.3.4 The tempering temperature and cooling rate of forgings should be appropriately selected. Under the premise of meeting the performance requirements, the tempering temperature should be as high as possible. After tempering, slow cooling should be carried out to ensure that the residual stress of the forging is not greater than 8% of the specified lower limit of yield strength. 4.1.3.5 The metallographic structure of forgings shall be uniform. For 28CrMoNiVE and 30CrMoNiVE, ferrite shall not appear in the core. 4.1.4 Stress relief treatment
4.1.4.1 Forgings are usually subjected to stress relief tempering by the supplier, and the temperature shall generally be within the range of 15~50℃ below the actual tempering temperature. 4.1.4.2
When the tempering cooling rate of the performance heat treatment is less than 25℃h, stress relief treatment may not be performed. When the residual stress inspection fails, stress relief treatment is still required. 4.1.5
Machining
The delivered forgings shall comply with the dimensions and surface roughness specified in the order drawing. When the supplier performs rough machining, a sample for acceptance by the supplier and buyer shall be reserved at the specified location. If stress relief treatment is required for forgings, it shall be performed after semi-finishing. 4.1.5.3
For rotors with center holes, the center hole shall be machined after rough machining and before stress relief treatment. 4.1.6
Forgings shall not be welded during manufacturing and packaging. 4.2
Steel grades and chemical composition
Unless otherwise specified in the contract, the chemical composition (melting analysis) of steel shall conform to the provisions of Table 1. Table 1
34CrMo1A
28CrMoNiVE
30CrMoNiVE
30CrIMo1VE
34CrNi3MoA
25CrNiMoVA
30Cr2Ni4MoVE
Note: 1) When vacuum carbon deoxidation is used, Si≤0.10%. 2
Chemical composition
JB/T70221993
Product analysis of forgings shall comply with the provisions of Table 1. Under the condition that the mechanical properties are qualified, the deviation specified in Table 2 is allowed. Table 2
Mechanical properties
Allowable deviation of chemical composition
The mechanical properties of forgings shall comply with the provisions of Table 3. Unless otherwise specified,
Table 3 Mechanical properties
34CrMo1A
28CrMoNiVE
30CrMoNiVE
30Cr1Mo1VE
34CrNi3MoA
25CrNiMoVA
30Cr2Ni4MoVE
Size range\)
≤1200
≤1000
Sampling position
Sampling position
Tangential, longitudinal
Tangential, longitudinal
Tangential, longitudinal
Core longitudinal
Tangential, longitudinal
Core longitudinal
600-750
570~7 20 | | tt | 0
≥680||tt ||700-850
700-850
≥620
≥680
860-970
[≥15]
[≥15]
[≥16]
[≥16]
Note: 1) The size range refers to the maximum diameter of the forging after rough machining and before performance treatment, for reference only.
2) The longitudinal test specimen is taken from the end face of the rough machined forging at 1/3 radius from the outer surface. 3) FATT. Whether the data is used as the basis for acceptance is stipulated in the order contract. 4.3.2
[≥47]
[≥47]
[≥47]
Charpy (V-notch) impact energy is the arithmetic mean of the single values of a group of 3 specimens. One of the single values is allowed to be lower than the specified value but shall not be lower than 70% of the specified value.
4.4 Hardness uniformity
The hardness difference between points on the same arc surface shall not exceed 30HBS. The hardness difference between points on the same busbar shall not exceed 40HBS4.4.2
Hardness value shall not be used as acceptance basis.
Non-destructive testing
General requirements
JB/T7022—1993
Forgings are not allowed to have defects such as cracks, white spots, shrinkage holes, looseness, folding and excessive segregation. 4.5.2 Pickling or magnetic particle inspection
Unless otherwise specified, the supplier shall ensure that the pickling or magnetic particle inspection complies with the following provisions. 4.5.2.1 The outer surface of the rotor body is not allowed to have defects greater than 1.5mm in length. 4.5.2.2 During the final inspection, except for parts such as bearings that are not allowed to be polished, if defects greater than 1.5mm are found, local grinding or polishing is allowed. The polishing depth shall not exceed 1.6mm and the transition to the circumferential surface is smooth. 4.5.3 Ultrasonic inspection
Unless otherwise specified, ultrasonic inspection shall comply with the following provisions. 4.5.3.1 Single scattered defects with an equivalent diameter of less than 1.6mm shall not be counted, but the noise height shall be less than 50% of the equivalent amplitude of 1.6mm. 4.5.3.29 All defects with an equivalent diameter of 1.6~3.5mm shall record their axial, radial and circumferential positions and indicate them in the certificate of conformity. However, the total number of defects with an equivalent diameter of 1.6~3.5mm shall not exceed 20, and defects with an equivalent diameter of 3.5mm are not allowed. 4.5.3.3 Except for the root groove depth of the circular blade plus 25mm and the range of the rotor body with a center hole within 75mm from the center hole surface, 3 defect dense areas with an equivalent diameter of less than 1.6mm are allowed in other parts. The size of the dense area in any direction shall not be greater than 20mm, and the distance between any two dense areas shall not be less than 120mm. 4.5.3.4 The bottom wave loss caused by defects exceeding 3dB shall be reported to the purchaser. 4.5.3.5 No wandering signal or continuous defect display is allowed. 4.5.3.6 The supplier shall provide material attenuation data measured at three locations on the rotor body (at the maximum diameter) using a 2~2.5MHz probe.
4.5.3.7 Defects exceeding the above requirements shall be reported to the buyer, and the supplier and buyer shall be organized to conduct re-inspection. Defect elimination or acceptance can only be carried out with the buyer's consent.
4.5.4 Center hole
The center hole inspection of rotor body forgings with center holes shall comply with the following provisions. 4.5.4.1 The axial and circumferential positions of defect displays equal to or greater than 1.5mm in length shall be recorded and reported to the buyer. 4.5.4.2 Three defect displays with a length greater than 1.5mm or nine defect displays with a length less than 1.5mm are not allowed within an area of 60cm2. 4.5.4.3 On the entire surface, the number of scattered defects with a length of 1.5~3mm shall not exceed 10, and the number of point defects with a length of less than 1.5mm shall not exceed 25, and chain-like distribution is not allowed. The cumulative total length of the above defects shall not exceed 50mm. 4.5.4.4 Dense areas composed of visible defects and non-metallic inclusions with a length greater than 3mm are not allowed. 4.5.4.5 No tearing or bifurcated defects are allowed. 4.5.4.6 When the distance between two defects on the same generatrix is less than 5 times the length of the larger defect, they shall be treated as a continuous defect. 4.5.4.7 For defects that do not meet the above requirements, local grinding and polishing of the defects are allowed after obtaining the consent of the purchaser, but the grinding and polishing depth shall not exceed 1.6mm and shall have a smooth transition with the circumferential surface. 4.6 Shape and size
4.6.1 The straightness tolerance value of the axis of the forging is?3mm. 4.6.2 The cylindrical tolerance of the center hole of the rotor body forging with a center hole is 0.3mm, and the coaxial tolerance of the center hole and the outer circle of the forging is 91mm.
4.7 Grain size and non-metallic inclusions
4.7.1 Grain size
When the grain size inspection is required, it should be indicated in the order contract. Unless otherwise specified, the average grain size shall not be coarser than level 4. 4.7.2 Non-metallic inclusions
When the non-metallic inclusion inspection is required, it should be indicated in the order contract. Unless otherwise specified, the four types of non-metallic inclusions A, B, C, and D shall not exceed level 3.
4.8FATTso
When the FATTso value is required to be inspected, the brittle transition temperature should be indicated and specified in the order contract. 4
4.9 Thermal stability test
JB/T70221993
4.9.1 During the operation of the unit, when the temperature rises rapidly and the temperature fluctuates, the rotor is still required to run very smoothly, or to eliminate the thermal stress generated at high temperature, the rotor forging should be subjected to thermal stability performance test. 4.9.2 The thermal stability test is carried out on the demand side. The supplier shall be responsible for the test results. 4.10 High-temperature mechanical properties
4.10.1 The rotor body of the same material, the same specification, and high-temperature operation produced for the first time shall be subjected to high-temperature mechanical properties measurement. 4.10.2 When the contractor is required to measure the high-temperature mechanical properties, the sampling location and requirements shall be indicated and specified in the order contract. 5 Inspection methods and inspection rules
5.1 Chemical analysis
5.1.1 Each furnace of molten steel shall be subjected to smelting analysis. 5.1.2
The sample for finished product analysis is taken from the tangential test ring of the forging. 5.1.3 Chemical analysis samples shall be taken in accordance with GB222. 5.1.4 Chemical analysis shall be taken in accordance with GB223 or other analysis methods that ensure the quality of analysis. 5.2 Mechanical properties
5.2.1 Sample sampling
Unless otherwise specified, mechanical properties samples shall be taken from forgings after performance heat treatment, and the sampling locations shall comply with the following provisions 5.2.1.1 Longitudinal test samples
a. For forgings with a delivery weight of less than or equal to 1 t, the supplier shall take 1 longitudinal tensile test sample and 3 impact test samples at 1/3 of the outer surface at either end, and at 1/2 of the wall thickness for forgings with center holes, and the purchaser shall take samples at the other end for acceptance; b. For forgings with a delivery weight of more than 1 t, 1 longitudinal tensile test sample and 3 impact test samples shall be taken at each end for acceptance. 5.2.1.2 Tangential test specimens
a. For forgings with a delivery weight of less than or equal to 6t, cut 1 tangential tensile test specimen and 3 impact test specimens on the steam inlet end of the shaft; b. For forgings with a delivery weight of more than 6t, take 1 tangential tensile test specimen and 3 impact test specimens at both ends of the shaft. 5.2.1.3 When using sawing sampling, double test specimens should be left for the forgings and the test specimen positions should be marked on the rough processing drawing. When using nesting sampling, the supplier and the buyer share the same shaft end test specimen.
5.2.2 The preparation and cutting of tensile test specimens should comply with the short proportion test specimens specified in GB6397. 5.2.3 Tensile test shall comply with the provisions of GB228. High temperature tensile test shall comply with the provisions of GB6395. 5.2.4 Impact test shall comply with the provisions of GB2106 or GB229. 5.3 Hardness uniformity
Performance Hardness uniformity inspection shall be carried out after heat treatment. 5.3.1
Inspection location
Measure 4 points at 90° intervals on the outer surface of the two journals and shaft parts of the forging, for a total of 12 points. 5.3.2 The hardness test method shall comply with the provisions of GB231. 5.4 Pickling or magnetic particle inspection
Pickling or magnetic particle inspection shall be carried out at the purchaser. 5.4.1 Inspection location and timing
5.4.1.1 After semi-finishing, pickling or magnetic particle inspection shall be carried out on the bearing part, the two end faces of the shaft body, and the transition zone of the shaft body. 5.4.1.2 After finishing, perform a macroscopic inspection of the surface, and a magnetic particle inspection may be carried out if necessary. 5.4.2 The magnetic particle inspection method shall comply with JB/ZQ6101 or other recognized methods. 5.4.3 Pickling inspection method: The surface roughness R of the pickled area is 1.6μm. When pickling, use 15% ammonium persulfate aqueous solution first, then use 10% nitric acid aqueous solution, and the pickling time is not less than 15min respectively. After pickling, two inspections are carried out, the first inspection is 10min after pickling, and the second inspection is not less than 12h after pickling. 5
5.5 Ultrasonic inspection
JB/T 7022—1993
5.5.1 Ultrasonic inspection should be carried out on all detectable surfaces of forgings after quenching and tempering and rough machining. 5.5.2 For forgings that need to be reheat treated, ultrasonic inspection shall be carried out again after reheat treatment. 5.5.3 Ultrasonic inspection method shall be in accordance with JB1581. 5.6 Thermal stability test
The thermal stability test shall be carried out after stress relief, and the inspection method shall be in accordance with ZBJ32005. 5.7 Center hole inspection
5.7.1 The center hole size and inner hole surface of the rotor forging with center hole should be inspected. 5.7.2 The center hole inspection is usually carried out by observation with a bore peep tester, and if necessary, magnetic particle inspection combined with bore peep tester observation. 5.8 Metallographic inspection
5.8.1 Unless otherwise specified, the grain size determination sample is taken from the body tangential sample, and the inspection method is in accordance with the provisions of GB6394. 5.8.2 Unless otherwise specified, the inspection method for non-metallic inclusions is in accordance with the provisions of Method A of GB10561, and the JK diagram is used for evaluation. 5.9 Residual stress
5.9.1 Residual stress inspection should be carried out before forgings leave the factory, and the sample is taken from the same part of the rotor body forging tangential sample. 5.9.2 Unless otherwise specified, the residual stress is generally determined by the ring cutting method or the ring core resistance strain method. The ring cutting method takes a ring with a sample size of 25mm×25mm, and the residual stress is calculated by measuring the average deformation of the ring before and after cutting. 5.9.3 Calculation formula for residual stress determined by ring cutting method: Where: - residual stress, MPa;
8 algebraic value of diameter increment, mm;
D - outer diameter of the ring before cutting, mm;
E elastic modulus of the material, MPa.
5.10 Retest
5.10.1 Retest is allowed when the mechanical property test results do not meet the specified requirements. However, retest is not allowed for samples that fail due to white spots or cracks.
When a test result fails due to equipment failure or poor sample preparation, a sample can be taken from the adjacent position of the forging for retest. 5.10.2
5.10.3When one of the tensile test results does not meet the requirements, two additional samples should be taken from the adjacent position of the original sample for tensile test, and the test results of the two samples should meet the requirements. 5.10.4 Retest is allowed when the room temperature impact value is lower than the specified lower limit. During the retest, a group of three samples should be taken from the adjacent position of the original sample for impact test. The impact values of all retest samples should exceed the specified lower limit, and the average value of the six samples including the initial test should also exceed the specified lower limit, otherwise they will not be accepted.
5.11 Reheat treatment
5.11.1When any mechanical property retest result of the forging still fails, reheat treatment is allowed and resampling is allowed. 5.11.2 The number of re-heat treatments for forgings shall generally not exceed two times (referring to re-heating). 6 Acceptance and certificate of conformity
6.1 The supplier shall inspect the forgings according to the items specified in this standard or the contract, and the inspection results shall comply with the regulations. The certificate of conformity shall be signed by the person in charge of the supplier's quality inspection department.
6.2 The purchaser may select certain items for re-inspection according to the inspection contents specified in this standard or the contract. If non-conformity is found during the re-inspection or subsequent processing inspection, the purchaser shall promptly notify the supplier and the two parties shall resolve the issue through consultation. 6.3 The supplier shall provide the purchaser's inspection personnel with necessary conveniences so that the purchaser's inspection personnel can carry out their work. 6
JB/T7022-1993
6.4 The supplier shall provide the purchaser with a certificate of conformity, which shall include the following contents: a. Contract number;
b. Forging drawing number;
c. Standard number, steel type, required yield strength; d. Melting furnace number, part number, ingot section number and melting method; e. Chemical analysis results;
f. Main dimensions of steel ingot and actual forging ratio; g. Actual temperature, holding time and cooling method of each heat treatment; h. Mechanical properties test results;
i. Ultrasonic test report;
j. Results of other tests and supplementary tests required by the purchaser; k. Actual dimensions and weight of the delivered forgings. 7 Marking and packaging
7.1 The supplier shall mark the contract number, furnace number, ingot section number, part number, etc. on each forging, which is equivalent to the lower end face of the steel ingot, and circle it with white paint. 2 The supplier shall apply rust-proof agent 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 remarks:
This standard is proposed and managed by the Deyang Large Castings and Forgings Research Institute of the Ministry of Machinery Industry. This standard is drafted by the Hangzhou Industrial Steam Turbine Research Institute. The main drafters of this standard are Cai Linghua, Chen Wei, Wan Youwen, Yu Sisun, and Ma Feiliang. 7
People's Republic of China
Mechanical Industry Standard
Industrial Steam Turbine Rotor Forgings
Technical Conditions
JB/T70221993
Published and issued by the China Academy of Mechanical Science
Printed by the China Academy of Mechanical Science
(No. 2 Shouti South Road, Beijing
Postal Code 100044)
Sheet 3/4
Format 880×1230
Word Count 14,000
First Edition in May 1994
First Printing in May 1994
Print Quantity 1-500
Price RMB 6.00
Mechanical Industry Standard Service Network: http://www.JB.ac.cn6
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