JB/T 7024-2002 Technical Specifications for Cylinder Steel Castings of Steam Turbines of 300MW and Above
Some standard content:
ICS77.140.80
Machinery Industry Standard of the People's Republic of China
JB/T7024-2002bzxz.net
Replaces JB/T7024—1993
Specification for steel castingsfor steam turbines casing(3ooMW or above) above)2002-12-27 issued
2003-04-01 implemented
issued by the State Economic and Trade Commission of the People's Republic of ChinaForeword
Normative references
3 Ordering requirements
4 Technical requirements
Manufacturing,
Chemical composition
Mechanical properties,
Casting quality...
Shape and size tolerance
Weight tolerance,
Non-destructive testing.
Test methods and inspection rules,
Chemical analysis.
Mechanical properties test
Non-destructive testing,
Certificate of conformity.
8 Marking, protection, packaging and transportation
Marking,
8.2 Protection
8.3 Packaging and transportation
Table 1 Mass fraction and allowable deviation of chemical composition...Table 2 Mechanical properties.
Table 3 Allowable residual height
Table 4 Allowable size deviation..
JB/T7024—2002
JB/T7024—2002
This standard replaces JB/T7024—1993 "Technical Conditions for 300~600MW Steam Turbine Cylinder Steel Castings". Compared with JB/T70241993, the main changes of this standard are as follows: the title and scope of application of the original standard are changed to the current title and scope of application; the overall arrangement and structure of the standard are modified according to GB/T1.12000 "Guidelines for Standardization Work Part 1: Structure and Numbering Rules of Standards": the surface roughness of the casting surface is specified: the mechanical properties in the original standard are revised. The specific situation is: the 5% of ZG20CrMoV and ZG15Cr1Mo1V steel is increased from 15% to 17%. The 6% values of ZG15Cr1Mo and ZG15Cr2Mo1 are added, which are 20% and 18% respectively; in addition, 64 is deleted, and the impact performance values and hardness values of these two materials are added: the lower limit of carbon content in ZG15Cr1Mo and ZG15Cr2Mo1 materials is specified to be 0.12%; the original standard appendix A, appendix B, appendix C and appendix D are cancelled. This standard is proposed by the China Machinery Industry Federation. This standard is under the jurisdiction of Deyang Large Castings and Forgings Research Institute. The drafting unit of this standard is Harbin Steam Turbine Plant Co., Ltd. The main drafters of this standard are Gong Jingyan, Wang Weili, Zhou Wencheng, Wei Shuangsheng, and Yang Xiaohui. This standard was first issued in 1993.
1 Scope
JB/T7024—2002
Technical conditions for steel castings for steam turbine cylinders of 300MW and above This standard specifies the technical requirements, inspection specifications, test methods, certificates of conformity and markings for steel castings for steam turbine cylinders of 300MW and above.
This standard applies to the ordering, manufacturing, inspection and acceptance of steel castings for steam turbine cylinders of 300MW and above (hereinafter referred to as castings, including welding accessories).
2 Normative references
The clauses in the following documents become the clauses of this standard through the reference of this standard. For all referenced documents with dates, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties that reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all referenced documents without dates, the latest versions are applicable to this standard. GB/T222 Sampling method for chemical analysis of steel and allowable deviation of chemical composition of finished products GB/T223.3~78 Chemical analysis methods for steel and alloys GB/T228 Metal tensile test method
9 Metal Charpy notch impact test method (GB/T229—1994, eqvISO148:1983) GB/T229
GB/T231 Metal Brinell hardness test method
Radiography and quality grading of steel fusion welded butt joints GB/T3323
GB/T5677
GB/T6414
Method for classification of steel parts by radiography and negative film dimensional tolerances and machining allowances for castings (GB/T6414—1999, eqvISO8062:1994) Penetrant testing of steel castings and rating method for defect indication marks GB/T9443
GB/T11351
GB/T15056
JB/T4058
Tolerance of casting volume
Casting surface roughness
Evaluation method
Steam turbine cleanliness
Technical conditions for hydraulic test of pressure-bearing parts of steam turbineJB/T9629
Magnetic particle testing and quality grading method for steam turbine steel castingsJB/T9630.1
JB/T9630.2Ultrasonic flaw detection and quality grading method for steam turbine steel castings 3 Ordering requirements
3.1 The purchaser shall provide rough processing and flaw detection drawings, and specify additional instructions other than the requirements of this standard in the order contract and order agreement. 3.2 Castings shall be delivered after heat treatment and rough machining and welding according to the drawings (if required by the drawings). 4 Technical requirements
4.1 Manufacturing
4.1.1 Refining
Electric furnace or other smelting methods that meet the requirements of this standard can be used with the consent of the purchaser. 4.1.2 Casting
4.1.2.1 Internal cooling iron and core support can only be placed in the machining removal position, and other positions are not allowed to be used. If it is necessary to use it in other positions, the written consent of the purchaser shall be obtained in advance, and materials with chemical composition close to that of the castings shall be used. 4.1.2.2 The surface roughness of the casting shall meet the requirements of the drawings. 1
JB/T7024—2002
4.1.3 Heat treatment
4.1.3.1 The heat treatment specifications shall be implemented in accordance with the provisions of the order technical agreement. 4.1.3.2 In addition to the performance heat treatment, the castings shall be subjected to stress relief heat treatment after rough machining, welding repair and welding. The temperature of stress relief heat treatment shall be 20℃50℃ lower than the actual tempering temperature of performance heat treatment. 4.1.4 Welding
The welder shall have a qualification certificate. The welding process shall be qualified after the welding process assessment. The supplier shall adopt the welding standard approved by the purchaser to standardize the welding and repair welding operations. Repair welding is allowed for defects exceeding the standard in the castings, and the defective parts shall be recorded. 4.1.4.3
4.1.4.4 Before repair welding, the defects in the defective area shall be cleaned. 4.1.4.5 In principle, repair welding should not be performed after the final stress relief heat treatment. If there are a few defects that need to be repaired, local stress relief treatment should be performed after welding and records shall be made.
4.2 Chemical composition
The molten steel shall be subjected to smelting analysis, and the mass fraction of its chemical composition shall comply with the provisions of Table 1. The results of the analysis of finished castings and the allowable deviations shall comply with the provisions of Table 1. Table 1 Mass fraction and allowable deviation of chemical composition%
ZG20CrMo
0.15~0.25
ZG15CrIMo
0.12~0.20
0.50~0.80
0.20~0.60
0.40~0.60||tt ||1.00~1.50
0.45~0.65
Material grade
ZG15Cr2Mo1
0.12~0.18
2.00~2.75
0.90~1.20
0.20~0.30
4.2.3 The residual aluminum content of each material in Table 1 shall not exceed 0.025%. ZG20CrMoV
0.18~-0.25
0.40~0.70
ZG15CrIMo1V
0.20~0.60
0.90~1.20
0.50~0.70
1.20~1.70
0.90~1.20
0.25~0.40
4.2.4 The residual content of nickel in ZG15Cr1Mo steel shall not exceed 0.5%; the residual content of copper shall not exceed 0.25%; the residual content of vanadium shall not exceed 0.03%; the residual content of titanium shall not exceed 0.035%, unless otherwise specified in the technical documents or contract, no assessment is generally required. 4.2.5 Except for ZG15Cr1Mo, the residual content of nickel and copper in other steel grades should not exceed 0.30%, and the allowable deviation of inlay is ±0.03. Unless otherwise specified in the technical documents or contract, no assessment is generally required. 4.3 Mechanical properties
4.3.1 The specimens used for mechanical properties test should be taken from the attached casting test block, and the test block size is 200mmx150mmx65mm. 4.3.2 The mechanical properties of the castings after heat treatment shall comply with the provisions of Table 2. 4.4 Casting quality
4.4.1 The surface quality of the casting shall comply with the requirements of the drawing. If not specified in the drawing, the surface roughness shall reach R.100um. 4.4.2. There shall be no defects such as cracks, sand adhesion, shrinkage holes, cold shuts, etc. on the surface of the parts. If there are any defects mentioned above, they should be completely removed. If the wall thickness exceeds the tolerance after the defects are removed, repair welding should be performed. 4.4.3 After the gate, riser, process subsidy and casting ribs on the non-machined surface are cut, the allowable residual height shall comply with the provisions of Table 3. All the remaining parts of the gate, riser, process subsidy and casting ribs and the parts of the cut pits shall be finished by arc gouging or grinding wheel to make their surfaces smoothly transition with the surface of the casting body and shall not affect the appearance quality. The depth of the depression shall not exceed the allowable tolerance of the wall thickness. 4.4.4 After the gate, riser, process subsidy and casting ribs on the machined surface are cut, the allowable residual height shall be between 0mm10mm. 2
JB/T7024-2002
4.4.5 The surface roughness of the machined surface to be subjected to ultrasonic flaw detection shall reach R,6.3um: the surface roughness of the non-machined surface shall reach R12.5uμm. Table 2 Mechanical properties
ZG20CrMo
ZG15Cr1Mo
ZG15Cr2Mo1
ZG20CrMoV
ZG15Cr1Mo1V
Yield strength
≥275
≥345
Note: Hardness is not used as the basis for acceptance,
Tensile strength
≥460
≥490
≥485
≥490
Elongation
Sectional reduction
Impact absorption energy
135~180
140~220|| tt||140220
Heat treatment
Normalizing+
Annealing+Normalizing
Annealing+Tempering
4.4.6The surface roughness of the machined surface that needs magnetic particle inspection should reach R,6.3um: the surface roughness of the non-machined surface should reach R,12.5um4.4.7The surface roughness of the machined surface that needs penetrant inspection should reach R6.3μm: the surface roughness of the non-machined surface should reach R12.5um4.4.8Surface cleanliness. If not specified in the drawings, the inner wall of the inner cylinder of the high and medium pressure cylinder shall comply with the requirements of JB/T4058 medium cleanliness-2, and the outer wall of the inner cylinder and the inner and outer walls of the outer cylinder shall comply with the requirements of JB/T4058 medium cleanliness-3. Table 3 Allowable residual height
Yaokou, Yingkou, process subsidy,
Maximum size of cast ribs
Allowable residual height
>100~200
>200~350
>350~500
Note 1: For castings containing vanadium steel, the positive deviation is allowed to be appropriately relaxed, but it should not exceed 50% of the values listed in the table. Note 2: When this provision is in conflict with 4.5.1 and 4.5.2, the provisions of 4.5.1 and 4.5.2 shall prevail. The following defects are allowed on the machined surface:
a) Casting defects with a depth not exceeding two-thirds of the machining allowance are allowed. >500~750
b) Single scattered pores, inclusions and shrinkage cavities not larger than Φ3mmx2mm are allowed on the mating surface. Unit: mm
On the friction surface and sliding surface, defects smaller than Φ1.5mm, no more than three in every 10cm area, and the distance between each two defects is not less than 3mm.
On the non-matching surface, defects smaller than Φ5mmx5mm, no more than 1/5 of the wall thickness, and the distance between each two defects is not less than 10mmd)
are allowed.
4.4.10On the non-processed surface, if the area of a single defect is less than 0.5cm2, the distance between two defects is not less than six times the maximum length of the defect, and the depth of the defect is less than the tolerance of the wall thickness, then two of the above defects are allowed to exist on each 100cm (10cmx10cm) unit surface, but the total unit area with defects on the entire surface should not exceed 1% of the total inspection area. 4.5 Tolerance of shape and size
4.5.1 The dimensional tolerance of castings shall comply with the provisions of the drawings. If no provisions are made in the drawings, they shall comply with the provisions of CT14 in GB/T6414. 4.5.2 The wall thickness tolerance of castings shall comply with the provisions of the drawings. If no provisions are made in the drawings, they shall comply with the provisions of CT15 in GB/T6414, and the upper deviation shall be 0.6 times the tolerance value, and the lower deviation shall be 0.4 times the tolerance value. 4.5.3 The dimensional limit deviation of the rough-machined surface of castings shall be implemented in accordance with the provisions of the drawings. If there is no clear provision in the drawings, it shall comply with the provisions of Table 4. 4.5.4 The misalignment value of the casting shall not exceed the dimensional tolerance of the wall thickness, and the misalignment shall be rounded (flat) and smoothly transitioned after finishing. 4.6 Weight tolerance
The weight tolerance of castings shall comply with the provisions of MT15 in GB/T11351. Except for the requirements of the contract, it is generally not assessed. 3
JB/T7024—2002
Basic size
≤125
>125~600
Table 4 Dimensional tolerance
Note: The total cumulative dimensional tolerance should not exceed the total dimensional tolerance. 4.7 Nondestructive testing
Plate limit deviation
Unit: mm
4.7.1 Castings shall be subjected to magnetic particle and ultrasonic testing in accordance with the provisions of the flaw detection drawings. Castings that need to be welded to pipes by the supplier shall be subjected to radiographic testing in accordance with the provisions of the drawings or agreements. 4.7.2 Defects that are not allowed to exist in castings shall be recorded. 4.7.3 The repaired welds of castings shall still be subjected to nondestructive testing in accordance with the quality requirements specified for the body. 5 Test methods and inspection rules
5.1 Chemical analysis
5.1.1 The molten steel for casting the parts shall be sampled for smelting analysis according to the smelting furnace number, and the test blocks shall be cast with molten steel in the middle of the casting. 5.1.2 The sampling method for chemical analysis samples shall comply with the provisions of GB/T222, 5.1.3 The chemical composition analysis method shall comply with the provisions of GB/T223.3~78. 5.1.4 The purchaser may take samples from the attached cast test blocks provided by the supplier or from the part 6mm below the surface of the casting to conduct chemical composition analysis of the product. 5.2 Mechanical properties test
5.2.1 The samples for mechanical properties test shall be taken from the attached cast test blocks. Each half cylinder delivered by the supplier shall be accompanied by at least one attached cast test block for acceptance inspection by the purchaser.
5.2.2 Before heat treatment, the attached casting test block should be cut out with appropriate glands, and not completely cut off, leaving a small part connected to the main body, so that it can be easily removed without hot cutting.
5.2.3 Take a tensile test specimen and three impact test specimens for each ZG20CrMo, ZG20CrMoV and ZG15Cr1Mo1V casting. The results of the tensile test shall comply with the provisions of Table 2; the average value of the three impact test results shall comply with the provisions of Table 2, and one of the test results is allowed to be lower than the specified value, but it should not be lower than 2/3 of the specified value. Take two tensile test specimens and three impact test specimens for each ZG15CrIMo and ZG15Cr2Mo1 casting. The results of the tensile test shall comply with the provisions of Table 2, and the average value of the three impact test results shall comply with the provisions of Table 2, and one of the test results is allowed to be lower than the specified value, but it should not be lower than 2/3 of the specified value.
5.2.4 The tensile test shall be carried out in accordance with the provisions of GB/T228, and the impact test shall comply with the provisions of GB/T229. If the specimen has casting defects, the test result is invalid and the specimen should be re-prepared for testing. 5.2.5
5.2.6 The hardness test method shall be carried out in accordance with the provisions of GB/T231. 5.2.7 The water pressure test can be carried out by the purchaser, and the water pressure test requirements shall be carried out in accordance with the provisions of JB/9629. If quality problems occur, the supplier shall bear the responsibility.
5.2.8 The evaluation of surface roughness shall be carried out in accordance with the provisions of GB/T15056. 5.2.9 Retest is allowed when the mechanical property test results are unqualified. For the tensile test retest, samples shall be taken from the corresponding attached test blocks, and double samples shall be prepared for retest. If the test results all meet the requirements of Table 2, they can be judged as qualified. If one of the test results is unqualified, the casting represented by it and the test block shall be reheat treated. For the impact test retest, samples shall be taken from the corresponding attached test blocks, and three samples shall be prepared for testing. If all three test results are qualified, they can be judged as qualified. If one of the test results is unqualified in the retest, the casting represented by it and the test block shall be reheat treated. 5.2.10 Without the consent of the purchaser, the number of heat treatments for castings and test blocks shall not exceed three times (tempering times are not included). If the test results are still unqualified, the batch of castings shall be scrapped. 5.2.11 If there are insufficient attached test blocks, sampling is allowed on the castings, and the sampling location shall be subject to the consent of the purchaser. 5.3 Nondestructive testing
5.3.1 General requirements
Before nondestructive testing, the castings shall be prepared according to the regulations, and the defects exceeding the standard shall be recorded. 5.3.2 Magnetic particle testing
5.3.2.1 The magnetic particle testing shall be carried out after the final heat treatment. JB/T7024—2002
5.3.2.2 The location and quality grade of the magnetic particle testing of castings shall comply with the provisions of the testing drawings. Other requirements shall comply with the provisions of JB/T9630.1 or be negotiated separately by both parties.
5.3.3 Ultrasonic testing
5.3.3.1 Ultrasonic testing shall be carried out after preliminary finishing or rough machining. 5.3.3.2 The location and quality grade of the ultrasonic testing of castings shall comply with the provisions of the testing drawings. Other requirements shall comply with the provisions of JB/T9630.2 or be negotiated separately by both parties.
5.3.4 Radiographic testing
The location and quality level of radiographic testing of castings shall comply with the provisions of the testing drawings and technical agreement, and other requirements shall comply with the provisions of GB/T3323 and GB/T5677 or be negotiated separately by both parties. 5.3.5 Penetrant testing
The location and quality level of penetrant testing of castings shall comply with the provisions of the testing drawings, and other requirements shall comply with the provisions of GB/T9443. If there are no special requirements, it is generally not carried out after rough processing. 6 Acceptance
6.1 The supplier shall submit qualified castings and relevant quality inspection records, test reports and qualification certificate documents in accordance with the provisions of this standard and technical agreement. 6.2 The purchaser has the right to re-inspect the qualified castings provided by the supplier according to the contents and items specified in the drawings, technical documents and technical agreement. 6.3 If the purchaser finds excessive defects in the qualified castings that have been accepted by the supplier during the re-inspection, or finds excessive defects in the subsequent processing process, the supplier shall bear the responsibility.
7 Certificate of Qualification
7.1 The certificate of qualification for castings shall include the following: a) Order contract number:
b) Part drawing number and name:
Material brand:
d) Standard number:
Melting furnace number:
Dimension inspection record:
Chemical analysis test report:
Mechanical property test report:
Non-destructive testing report:
Heat treatment status, actual operation process parameters of heat treatment and furnace batch number: Copy of defect welding repair record:
Special project inspection report specified in the technical agreement: 1
m) Supplier’s factory name or its identification mark.
7.2 The certificate of conformity shall be signed and stamped by the supplier's inspection department and person in charge 8 Marking, protection, packaging and transportation
8.1 Marking
JB/T7024—2002
8.1.1 The permanent mark is located in the center of the side of the casting flange. After the final heat treatment, the surface is polished or machined to be smooth, and the following content is printed or engraved:
The supplier's factory name abbreviation or its identification mark;
b) Order contract number:
Parts drawing number:
Smelting furnace number:
Supplier or inspector code or mark of both the supply and demand parties. The temporary mark is located at 45 of the outer circle of the casting, and is written in standard large characters with paint. The content is as follows:8.1.2
Parts drawing number:
b) Smelting furnace number:
c) Material brand.
The supplier shall adopt appropriate protective measures at appropriate process points to prevent the castings from rusting. If the castings need to be painted, this shall be clearly stated in the technical agreement or contract.
8.3 Packaging and Transportation
The packaging and transportation of castings shall ensure that the castings are not damaged or rusted.
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