JB/T 7178-2002 Technical requirements for 300MW~600MW turbine generator rotor forgings
Some standard content:
ICS 77.140.85
Machinery Industry Standard of the People's Republic of China JB/T 7178---2002
Replaces JB/T7178-1993
Specification for rotor forgings for 300MW to 600MW turbine generators2002-12-27 Issued
Implemented on 2003-04-01
Issued by the State Economic and Trade Commission of the People's Republic of ChinaForeword
Normative references
Ordering requirements
Technical requirements.
Manufacturing process,
Chemical composition
Mechanical properties,
Residual stress,
Magnetic properties.
Grain size
Non-destructive testing
Dimensions, tolerances and surface roughness
Inspection rules and test methods
Chemical composition analysis,
Mechanical properties inspection
Residual stress test,
Magnetic properties determination
Grain size determination
Non-destructive testing,
Retest and re-heat treatment
6 Acceptance and certificate of conformity.
Marking and packaging
Table 1 Mass fraction of chemical composition
China Blood Specialized
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Table. Finished product analysis Permissible deviation exceeding the upper and lower limits and finished product analysis of impurity elements. Table 3
Mechanical properties
JB/T 7178—2002
JB/T7178--2002
This standard replaces JB/T7178--1993 "Technical conditions for 300-600MW steam turbine generator rotor forgings". Compared with JB/T7178--1993, the main features of this standard are as follows: The foreword is added to the standard:
The overall arrangement and structure of the standard are modified according to GB/T1.1-2000 "Guidelines for the work of standards Part 1: Structure and writing rules of standards";
In the original standard table 1, the mass fraction of chemical composition, Si was changed from 0.15% to 0.35% to ≤0.10%; Cu≤0.20% was changed to ≤0.15%; impurity elements were added: Sba≤0.0015%, Al≤0.010%, As≤0.020%, Sn≤0.015%; in the original standard table 2, the mass fraction deviation of finished product analysis, Si was changed from ≤0.05% to ≤0.02%, and impurity elements were added: Cu≤0.17%, Sb≤ 0.0017%. Al≤0.012%, As≤0.025%. Sn≤0.017% Requirements: In the mechanical properties of the original standard Table 3, the tensile strength is changed from αb≥670MPa, 740MPa to α=690MPa, 760MPa. The elongation is changed from 54=18%, 17% to 64≥20%, 18%: From the original Akv≥100J90J to Akv≥115J, 105J:
In the original standard 4.5, magnetic properties: changed The original (50.0×103)A/mB≥2.05T was changed to (47.0×103)A/m2B≥2.02T and the original (120.0×10°)Am2B≥2.13T was changed to (118.0×103)A/m2B≥2.12T; - In the original standard 5.2.3.3: a) Take two tensile specimens (one each) at the bottom of the groove of the two nesting rods, and take a room temperature impact specimen and a specimen for measuring the brittle transition temperature at the outer end close to the tensile specimen. And b) The other two nesting rods should adopt the opposite method, that is, take two tensile specimens (one each) at the outer end, take a room temperature impact specimen and a specimen for measuring the brittle transition temperature at the bottom of the groove. Now it is modified to 1) Take a tensile specimen and two room temperature impact specimens on a busbar in 5.2.3c). 2) Take a tensile test specimen and two test specimens for measuring the brittle transition temperature on another busbar that is symmetrical in diameter:
In the original standard 5.3.1, the ring core method for measuring residual stress standard JB/T8888 was added. This standard was proposed by the China Machinery Industry Federation. This standard is under the jurisdiction of Deyang Large Castings and Forgings Research Institute. The reforming units of this standard: Dongfang Electric Co., Ltd., Harbin Large Electric Motor Research Institute. The main drafters of this standard: Xuan Pinfan, Guo Chenghai. This standard was first issued in 1993.
1 Scope
JB/T 7178--2002
Technical conditions for 300MW-600MW steam turbine generator rotor forgings This standard specifies the technical requirements, inspection rules, test methods, certificates and marks of vacuum-treated alloy steel forgings for 300MW~600MW steam turbine generator rotors.
This standard is applicable to the ordering, manufacturing and inspection of vacuum-treated alloy steel forgings for 300MW600MW steam turbine generator rotors. 2 Normative reference documents
The clauses in the following documents become the clauses of this standard through reference in this standard. For all dated referenced documents, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all undated referenced documents, the latest versions are applicable to this standard. GB/T223.3～78 Chemical analysis methods for steel and alloys JB/T1581-1996 Ultrasonic flaw detection method for turbine and turbo-generator rotor and main shaft forgings JB/T8468 Magnetic particle inspection method for forged steel parts
JB/T8888 Test method for measuring residual stress in turbine and turbo-generator rotor forgings by ring core method YB/T5148 Determination method for average grain size of metals ASTMA341: Test method for determining DC magnetic properties of materials by DC impact method ASTMA370 Test methods and definitions for mechanical properties of steel products ASTME381 Macroscopic etching test method for steel products (including bars, square steel bars, large square bars and forgings) 3 Ordering requirements
3.1 The purchaser shall specify the adopted standards, forging grades, steel grades, corresponding technical requirements and inspection items, as well as other additional instructions in the order contract or technical agreement.
Forging grade and steel number shall be marked on the drawing as follows: Steel number
Forging grade text standard number
3.2 The purchaser shall provide a rough machining drawing indicating the location of the mechanical properties test specimen (provide the finishing dimensions if necessary). 4 Technical requirements
4.1 Manufacturing process
4.1.1 Refining and casting
4.1.1.1 Forging steel 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 Before or during ingot casting, the molten steel shall be vacuum degassed. During the vacuum treatment process, the ultimate pressure of the vacuum system shall generally be lower than 133Pa.
4.1.2 Forging
4.1.2.1 The upper and lower ends of the ingot shall have sufficient removal to ensure that the forging has no shrinkage cavities and unacceptable segregation. 4.1.2.2 Forging should be performed on a forging press with sufficient capacity so that the entire cross section of the forging is fully forged. The axial centerline of the forging and the ingot should roughly coincide. The end of the ingot with better quality should be the turbine end of the forging. 4.1.3 Fillet
At each manufacturing stage, corresponding fillets should be retained at the different step transitions where the forging diameter changes. 1
JB/T 7178--2002
4.1.4 Heat treatment
4.1.4.1 Post-forging heat treatment is normalizing and tempering. 4.1.4.2 Performance heat treatment is quenching and tempering, which should be carried out in a vertical state. The quenching cooling rate on the circumference and the entire length of the forging should be as consistent as possible.
4.1.4.3 After rough machining and rough boring to the inner and outer diameters specified in the order drawing and leaving a margin of less than 13mm, the forgings shall be subjected to stress relief treatment to ensure low residual stress. 4.1.4.4 For stress relief treatment, the forgings shall be heated to at least 550℃ and not less than 40℃ below the tempering temperature, kept at a temperature long enough to be completely burned through, and then cooled to 250℃ at a cooling rate not exceeding 15℃/h and air-cooled out of the furnace. 4.1.5 Machining
4.1.5.1 The supplier shall drill the center hole of the forging before stress relief treatment. 2 After the performance heat treatment, take the core drop specimen of the center hole. 4.1.5.2
4.1.5.3 After stress relief treatment, the center hole shall be finely bored and polished or polished in a way that does not cover defects. The surface roughness R value is 1.6μm.
Forgings shipped shall comply with the dimensions, tolerances and surface roughness requirements specified in the purchaser’s order drawings. 4.1.5.42
4.2 Chemical composition
Steel smelting analysis shall comply with the provisions of Table 1.
Forging finished product analysis shall comply with the provisions of Table 1. The finished product analysis deviation and impurity elements are shown in Table 2. Table 1 Chemical composition mass fraction
Cu丨Sb?
As 1 Sn
25Cr2N4Mov0.250.150.350.100.0150.0181.50~2.03.25~4.00|0.20~0.500.05~0.130.150.00150.0100.0200.015. Sb is for reference only and is not subject to assessment.
Table 2 Product analysis of the allowable deviation disk and impurity elements exceeding the upper and lower limits of the specified product analysis Pot number
25Cr2Ni4MoVbzxz.net
·Sb is for reference and not for assessment.
Deviation disk
0.0030.07
4.2.3 The hydrogen content gas fraction of the forging is not allowed to exceed 1×10-6.4.3 Mechanical properties
4.3.1 The mechanical properties of the forging shall comply with the provisions of Table 3. Mo
Product analysis of impurity elements
≤0.0120.025≤0.017
≤0.0017
4.3.2 The fluctuation value of the radial tensile strength or yield strength of the forging shaft is not allowed to exceed 40MPa. 4.4 Residual stress
The residual stress of the forging is not allowed to exceed 60MPa. 4.5 Magnetic properties
Magnetic properties should meet the following requirements:
H= (5.0x10\) A/m B≥1.60TH= (15.0x103) A/m B≥1.80TH=(47.0x103) A/m B≥2.02T
H= (118.0x103) A/m B≥2.12TWhere H is the magnetic field intensity and B is the magnetic induction intensity. 2
FATTso
Sampling position
Table 3 Mechanical properties
Longitudinal, tangential, radial
Longitudinal of center hole core rod
Longitudinal, tangential, radial
Longitudinal of center hole core rod
Longitudinal, tangential, radial
Longitudinal of center hole core rod
Longitudinal, tangential, radial
Longitudinal of center hole core rod
Longitudinal, tangential, radial
Longitudinal of center hole core rod
Longitudinal, tangential, radial
Longitudinal of center hole core rod
Note: When other indicators are qualified, the value of 00.2 is allowed to exceed the upper limit. 4.6 Grain size
590~690
540-690
≥690
≥620
≥115
Forging grade
JB/T7178—2002
660~-760
610~760
≥760
≥690
The grain size of radial specimen shall not be coarser than Grade 5, and that of Grade 4 shall not exceed 5%. The grain size inspection result report of center hole mandrel specimen shall be submitted to the purchaser and shall not be used as the basis for acceptance.
4.7 Nondestructive Testing
4.7.1 Magnetic Particle or Pickling Test
4.7.1.1 Forgings shall be free of white spots, cracks, folds and other defects. The buyer reserves the right to use various tests, including pickling and magnetic particle testing. 4.7.1.2 The buyer shall carry out pickling or magnetic particle testing on a section of R transition zone (one at each end) 200mm outward from both ends of the forged shaft and two bearing parts.
4.7.1.3, the results of magnetic particle or pickling test on the bearing parts and the transition zone at both ends of the shaft shall meet the following requirements: On an area of 25cm2 (referring to a rectangle with a maximum side length of 15cm), five single defects with a length of 0.5mm to 1.0mm are allowed to be displayed, a)
or two single defects with a length greater than 1.0mm to 1.5mm are allowed to be displayed. No more than 15 single defects are allowed to be displayed on each bearing part. Each transition zone is not allowed to have more than 20 single defects.
When the above provisions are exceeded, the supply and demand parties shall negotiate to deal with it. c
Ultrasonic flaw detection
Ultrasonic flaw detection is carried out on the outer cylindrical surface of the forging, and the results shall comply with the following provisions: a) Cracks, white spots, shrinkage holes and other defects are not allowed. b) Continuous defect signals and floating defect signals with an equivalent diameter equal to or greater than 1.6mm are not allowed. Defects with an equivalent diameter of less than 1.6mm are not counted, and defects with an equivalent diameter of equal to or greater than 1.6mm should be recorded and reported to the buyer. c)
Defects with an equivalent diameter of 1.6mm to 3.5mm are allowed, but the distance between two adjacent defects shall not be less than d)
10 times the diameter of the larger equivalent defect, and the total number of defects shall not exceed 30. In the area with high stress (within the range of the center hole diameter plus 60mm, and the outer groove depth plus 25mm), no defects with an equivalent diameter greater than 2mm and dense defect signals greater than or equal to an equivalent diameter of 1.6mm are allowed. f) When using a frequency of 2MHz to 2.5MHz for flaw detection, the attenuation of the bottom wave caused by the defect is not greater than 6dB, and the attenuation coefficient of the forging material is less than or equal to 4dB/m.
JB/T 7178—2002
4.7.3 Center hole
4.7.3.1 When inspecting with a bore peep tester, cracks, shrinkage cavity residues, pores, slag inclusions, harmful scratches, and defects greater than 3mm in length are not allowed on the inner surface of the center hole. The total number of various defects is not allowed to exceed 30. The specific provisions are as follows: a) The number of defects with a length of 0.5mm to 1.5mm gathered on an area of 60cm2 is not allowed to exceed 10. b) The number of defects with a length of 1.5mm to 3mm shall not exceed 10. On the inner surface of the entire center hole, the number of point defects with a length of 0.5mm to 1.5mm shall not exceed 25, and c)
defects distributed in a chain are not allowed.
4.7.3.2 If local trimming or enlargement of the center hole is required to remove larger defects, the purchaser's consent must be obtained in advance. 4.7.3.3 If the purchaser requires magnetic particle inspection of the center hole, it can be carried out by the purchaser. In the event of objections to the magnetic particle inspection, the supply and demand parties shall negotiate and deal with it. 4.8 Dimensions, tolerances and surface roughness
4.8.1 The processing of forgings shall comply with the dimensions, tolerances and surface roughness requirements specified in the purchaser's order drawings. 4.8.2 The roundness error of the center hole shall not exceed 0.3mm. The surface roughness R value of the center hole is 1.6μm. The coaxiality error between the center hole and the outer circle shall not exceed 1.0mm. The straightness tolerance of the center hole axis is within the cylinder with a diameter of 6mm. 5 Inspection rules and test methods
5.1 Chemical composition analysis
5.1.1 Melting analysis
5.1.1.1 The supplier shall take samples for melting analysis when casting each furnace of molten steel ingots and report the analysis results. The weight analysis results shall also be reported when multiple furnaces are cast.
5.1.1.2 If the sample is not suitable for melting analysis, the supplier may take a substitute sample from a suitable position near the surface of the ingot or forging, and inform the supplier of the analysis results and sampling location.
5.1.2 Finished product analysis
The supplier shall conduct finished product analysis for each forging. The sample is taken from the longitudinal sample of the mechanical properties of the forging, and can also be taken from the radial performance sample.
5.1.3 Gas analysis
Take radial samples to analyze the hydrogen content.
5.1.4 Analysis method
Perform according to GB/T223.3~78 and related methods. 5.2 Mechanical property test
5.2.1 After performance heat treatment or stress relief treatment, perform according to ASTMA370 method. 5.2.2 Impact specimens shall be in accordance with the provisions of Charpy V-notch specimens in ASTMA370. The notch direction of radial impact specimens shall be tangential. 5.2.3. If there are no special requirements, the sampling position and number of samples shall comply with the following provisions: a) Longitudinal samples: The supplier and the buyer shall take two tensile samples and two impact samples at both ends of the forging. Forgings with center holes shall be sampled at 1/2 of the wall thickness, and forgings without center holes shall be sampled at 1/3 of the radius from the surface. Tangential samples: Tangential samples shall be cut from test rings cut as close to the 1/3 radius of the shaft surface as possible at both ends of the shaft body. The supplier shall cut the ring at the end of the shaft body with poor quality, and the buyer shall cut the ring at the other end. Four tensile samples and two impact samples shall be taken from each end of the test ring, and they shall be cut at the same relative position of the test ring. c) Radial samples: Radial material bars shall be sleeved along the radial busbar parallel to the axis, and the distance from the two ends of the shaft body shall not be less than 200mm. The hole diameter and hole depth after sleeved shall comply with the requirements of the order drawing. The cutting of samples shall comply with the following provisions: 1) One tensile sample and two room temperature impact samples shall be sleeved on one busbar. 2) Take a tensile test specimen and two test specimens for measuring the brittle transition temperature on another busbar that is symmetrical to the diameter. 3) The impact test specimen for measuring the brittle transition temperature shall be carried out at the temperature specified in Table 3, and both test specimens shall show at least 50% of the plastic fracture.
JB/T 7178—2002
4) The radial tensile test specimen may be a test specimen with a diameter of not less than 5mm, and the radial impact test specimen may be a test specimen of 10mmx10mmx55mm (V-notch).
d) Center hole test specimen: Take a tensile test specimen on the mandrel at each end and the middle of the shaft body, and take at least four impact test specimens on the mandrel in the middle of the shaft body to determine the value of the brittle transition temperature. 5.3 Residual stress test
5.3.1 The residual stress shall be determined by the ring cutting method or the ring core method according to JB/T8888. 5.3.2 Ring cutting method: The supplier and the buyer take a 25mm×25mm ring at one end of the forging shaft, and calculate the residual stress by measuring the average deformation of the ring before and after cutting. The calculation formula is: 0=E6D
Where:
a residual stress, unit is MPa;
E-elastic modulus of the material, unit is MPa: S
-algebraic value of diameter increment, unit is mm; D-outer diameter of the ring before cutting, unit is mm. 5.3.3 When the residual stress is unqualified, the forging can be supplemented with tempering. The residual stress inspection results after supplementary tempering shall comply with the provisions of 4.4. 5.4 Magnetic property measurement
The buyer shall measure the magnetic properties of the forging. Unless otherwise specified by the buyer, it shall be carried out in accordance with the method specified in ASTMA341. Take a magnetic property specimen on the tangential test ring of the shaft, and its size shall be determined according to the equipment of each factory. 5.5 Grain size determination
On the shaft radial specimen near the bottom of the groove and the end surface of the center hole mandrel specimen, according to the method specified in YB/T5148! 5.6 Nondestructive testing
5.6.1 Magnetic particle or pickling inspection
5.6.1.1 The buyer shall pickle the parts specified in the order drawing after semi-finishing with a single side margin of 2mm and a surface roughness R value of 0.8μm.
5.6.1.2 Pickling shall be carried out according to the method specified in ASTME381. 5.6.1.3 If the buyer requires magnetic particle inspection, it shall be carried out according to the method specified in JB/T8468. 5.6.2 Ultrasonic flaw detection inspection
After rough machining and performance heat treatment, it is carried out according to the JB/T1581-1996 method, but the "defect signal with an equivalent diameter of not less than 2mm" in the definition of defect signals in this method is adjusted to "defect signal with an equivalent diameter of not less than 1.6mm". 5.6.3 Center hole inspection
After the surface roughness R value of the center hole reaches 1.6μm, use a bore peep tester or a magnetic particle combined with a bore peep tester to inspect the entire inner hole surface. The magnetic particle inspection is carried out according to the JB/T8468 method. 5.7 Retest and reheat treatment
5.7.1 Retest is allowed if the mechanical property test results do not meet the requirements. Retest is not allowed when the test results are unqualified due to cracks or white spots.
5.7.2 If the test results of any sample are unqualified, select two samples at adjacent positions for retest, and the test results of both samples must meet the requirements.
5.7.3 If the retest result of the mechanical property test is still unqualified, the supplier may reheat treat the forging. Without the consent of the purchaser, the number of reheat treatments shall not exceed three times. Reheat treated forgings shall be inspected in accordance with the provisions of 5.2. 5.7.4 When reheat treating forgings, the remaining center hole core rod shall be put back into the center hole. JB/T 7178—2002
6 Acceptance and certificate of conformity
The supplier shall provide the purchaser's inspector with necessary convenient conditions to facilitate the purchaser's inspector's work. The purchaser's inspector shall not cause unnecessary obstruction to the supplier's production. Unless otherwise specified, the inspection shall be carried out at the supplier. 6.2 Forgings shall be accepted by the supplier's quality inspection department in accordance with this standard before they can be re-inspected in accordance with this standard. 6.3 The supplier shall provide the purchaser with a certificate of conformity, including the following: Order contract number:
Forging drawing number, steel grade:
Standard number and forging grade number:
Melting furnace number, forging card number:
Melting analysis and finished product analysis results:
Mechanical properties test results;
Non-destructive test results, including defect distribution sketch: h)
Final austenitizing temperature and tempering temperature and cooling method: Other required test results.
6.4 After the supplier's acceptance, if the purchaser re-inspects and during the processing, if any unacceptable defects are found, the purchaser shall promptly notify the supplier and the two parties shall negotiate to resolve the issue.
7 Marking and packaging
7.1 The supplier shall mark the supplier's factory name or logo, contract number, melting furnace number and forging card number on the end face of each forging equivalent to the lower end of the steel ingot, and circle them with white paint.
7.2 The center hole of each forging should be coated with antiseptic and sealed with a wooden plug to prevent damage or corrosion during transportation and storage.2 If the test result of any sample is unqualified, two samples at adjacent positions shall be selected for retesting, and the test results of both samples must meet the requirements.
5.7.3 If the retest result of the mechanical property test is still unqualified, the supplier may reheat treat the forging. Without the consent of the buyer, the number of reheat treatments shall not exceed three times. The reheat treated forgings shall be inspected in accordance with the provisions of 5.2. 5.7.4 When the forgings are reheat treated, the remaining center hole core rod shall be put back into the center hole. JB/T 7178—2002
6 Acceptance and certificate of conformity
The supplier shall provide the necessary convenience to the buyer's inspector so that the buyer's inspector can carry out his work. The buyer's inspector shall not cause unnecessary obstruction to the supplier's production. Unless otherwise specified, the cutting test shall be carried out at the supplier. 6.2 Forgings shall be accepted by the supplier's quality inspection department in accordance with this standard before they can be retested in accordance with this standard. 6.3 The supplier shall provide the purchaser with a certificate of conformity, including the following: Order contract number:
Forging drawing number, steel grade:
Standard number and forging grade number:
Melting furnace number, forging card number:
Melting analysis and finished product analysis results:
Mechanical properties test results;
Non-destructive test results, including defect distribution sketch: h)
Final austenitizing temperature and tempering temperature and cooling method: Other required test results.
6.4 After the supplier's acceptance, if the purchaser re-inspects and processes forgings and finds any unacceptable defects, the purchaser shall promptly notify the supplier and the two parties shall negotiate to resolve the issue.
7 Marking and packaging
7.1 The supplier shall mark the supplier's factory name or logo, contract number, melting furnace number and forging card number on the end face of each forging equivalent to the lower end of the steel ingot, and circle them with white paint.
7.2 The center hole of each forging should be coated with antiseptic and sealed with a wooden plug to prevent damage or corrosion during transportation and storage.2 If the test result of any sample is unqualified, two samples at adjacent positions shall be selected for retesting, and the test results of both samples must meet the requirements.
5.7.3 If the retest result of the mechanical property test is still unqualified, the supplier may reheat treat the forging. Without the consent of the buyer, the number of reheat treatments shall not exceed three times. The reheat treated forgings shall be inspected in accordance with the provisions of 5.2. 5.7.4 When the forgings are reheat treated, the remaining center hole core rod shall be put back into the center hole. JB/T 7178—2002
6 Acceptance and certificate of conformity
The supplier shall provide the necessary convenience to the buyer's inspector so that the buyer's inspector can carry out his work. The buyer's inspector shall not cause unnecessary obstruction to the supplier's production. Unless otherwise specified, the cutting test shall be carried out at the supplier. 6.2 Forgings shall be accepted by the supplier's quality inspection department in accordance with this standard before they can be retested in accordance with this standard. 6.3 The supplier shall provide the purchaser with a certificate of conformity, including the following: Order contract number:
Forging drawing number, steel grade:
Standard number and forging grade number:
Melting furnace number, forging card number:
Melting analysis and finished product analysis results:
Mechanical properties test results;
Non-destructive test results, including defect distribution sketch: h)
Final austenitizing temperature and tempering temperature and cooling method: Other required test results.
6.4 After the supplier's acceptance, if the purchaser re-inspects and processes forgings and finds any unacceptable defects, the purchaser shall promptly notify the supplier and the two parties shall negotiate to resolve the issue.
7 Marking and packaging
7.1 The supplier shall mark the supplier's factory name or logo, contract number, melting furnace number and forging card number on the end face of each forging equivalent to the lower end of the steel ingot, and circle them with white paint.
7.2 The center hole of each forging should be coated with antiseptic and sealed with a wooden plug to prevent damage or corrosion during transportation and storage.
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