JB/T 7026-1993 Technical requirements for turbine generator rotor forgings below 50MW
Some standard content:
Mechanical Industry Standard of the People's Republic of China
Technical Conditions for Rotor Forgings of Steam Turbogenerators Below 50MW
*Subject Content and Scope of Application
JB/T 7026-—93
This standard specifies the technical requirements, inspection rules, test methods, certificates and marks for rotor forgings of steam turbine generators below 50MW.
This standard applies to the ordering, manufacturing and inspection of rotor forgings of steam turbine generators below 50MW. 2 Reference standards
GB 229
GB6397
JB1581
Sampling method for chemical analysis of steel and allowable deviation of chemical composition of finished products Chemical analysis methods for steel, iron and alloys
Metal tensile test method
Metal Charpy (U-notch) impact test methodMetal Brinell hardness test method
Metal tensile test specimen
Ultrasonic flaw detection method for turbine, turbo-generator rotor and main shaft forgingsJB/ZQ6101 Magnetic particle inspection method for forged steel partsJB/ZQ6157 DC impact methodTest method for determining DC magnetism of materials3 Ordering requirements
3.1 The purchaser shall specify the adopted standards, steel grades, forging grades, corresponding technical requirements, inspection items and other additional instructions in the ordering contract or technical agreement.
Forging grade and steel number shall be marked on the drawing as follows: Steel number
Forging grade × number of this standard
3.2 The purchaser shall provide a forging ordering drawing indicating the sampling location for mechanical property test. 4 Technical requirements
4.1 Manufacturing process
4.1.1 Smelting
Steel for forgings shall be smelted in an alkaline electric furnace, and other smelting methods are allowed. Vacuum treatment shall be used as much as possible. 4.1.2 Forging
4.1.2.1 The upper and lower ends of the steel ingot for forgings shall have sufficient removal to ensure that the forgings have no shrinkage cavities and unacceptable segregation. 4.1.2.2 Forging shall be carried out on a forging press with sufficient capacity so that the entire cross section of the forging is fully deformed. The center line of the forging and the steel ingot shall roughly coincide, and the end of the steel ingot with better quality shall be the turbine end. 4.1.3 Heat treatment
Approved by the Ministry of Machinery Industry on September 21, 1993
Implemented on July 1, 1994
JB/T 7026--93
4.1.3.1 For forgings, the post-forging heat treatment shall be properly normalized and tempered according to the geometric size and chemical composition of the forgings. 4.1.3.2 The performance heat treatment of forgings shall include quenching and tempering. If the purchaser agrees, normalizing and tempering are also allowed. Performance heat treatment shall be carried out in a vertical state as far as possible.
4.1.4 Machining
Forgings shipped by the supplier shall meet the roughness and size requirements specified in the purchaser's order drawings. 4.2 Chemical composition
4.2.1 The smelting analysis of steel for forgings shall comply with the requirements of Table 1. Table 1
34CiMo1A
34CrNiiMo
34CrNi3Mo
25CrNi1MoV
0.320.400.50~0.800.170.37
0.50~0.80bzxz.net
0. 30 -~ 0. 38
0. 30~~0.40
0.40~0.70
0.50~~0.80
0.30~~0.40
0. 50-~0.80
0.20~~0.280.30~~0.60
0. 17~0. 37
0.17~0. 37
0. 17~~0. 37
0. 17-~0. 37
Chemical composition
≤0. 0250, 7~1. 2
≤0.400.40~0.55
≤0.0251.3~1. 71.30~1.700.20~0.30≤0. 025 0. 7 -
1. 12. 75-~3. 25~~0. 40V
≤0. 025 1. 0~1. 51. 00~1. 500. 25~~0. 400. 05~-0. 150. 17-0. 37
Note: For vacuum carbon deoxidized steel, the silicon content is not more than 0.10%. When analyzing the finished product of forgings, the chemical composition should comply with the provisions of Table 1, but the deviation of Table 2 is allowed. 4.2.2
Table 2 Allowable deviation of chemical composition
Maximum range of specifications
Mechanical properties
0. 21~0. 40
The mechanical properties of forgings shall comply with the provisions of Table 3
Maximum diameter of rough-machined forgings, mm
291-~410
411-~570
571~~810
Recommended steel
Sampling position
Longitudinal direction of shaft end
Tangential direction of shaft body
Radial direction of shaft body
Longitudinal direction of shaft end
Tangential direction of shaft body.
Radial direction of shaft
Longitudinal direction of shaft end
Tangential direction of shaft
Diameter of shaft
Longitudinal direction of shaft end
Tangential direction of shaft
Radial direction of shaft
Longitudinal direction of shaft end
Tangential direction of shaft
Note: The values in the table are minimum values
4.4 Residual stress
JB/T 7026—93
Mechanical properties
34CrMolA
34CrNi1Mo
34CrMo1A
34CrNiiMo
25CrNi1MoV
Both the supplier and the buyer shall check the residual stress of forgings, and the result shall not be greater than 10% of the actual measured service point in the tangential direction. 4.5 Pickling or magnetic particle inspection
4.5.1 The buyer shall conduct magnetic particle or pickling inspection on the bearing parts at both ends of the forgings. There shall be no defects such as cracks, white spots, heavy skin, etc. 440
34CrMo1A
34CrNi1Ma
34CrNi3Mo
25CrNiMoV
4.5.2 The bearing parts shall be allowed to have no more than 5 single defects with a length of 1mm on an area of 25cm2, or no more than 2 single defects with a length of less than 1.5mm. Each bearing part shall not be allowed to have more than 15 defects. If defects exceeding the above provisions are found, the two parties shall negotiate and deal with them.
Note: The area of 25cm2 refers to the rectangular area with a maximum side length of 15cm. The defect length is based on pickling. 4.6 Ultrasonic flaw detection inspection
4.6.1 The outer cylindrical surface of the forging shall be subjected to ultrasonic flaw detection inspection, and the inspection results shall comply with the following provisions. 4.6.1.1 Cracks, white spots and shrinkage holes are not allowed. 4.6.1.2 Defects with an equivalent diameter of less than 2mm are not counted. 4.6.1.3 Continuous defect signals, dense defect signals and wandering signals are not allowed. 4.6.1.4 Dispersed single defects with an equivalent diameter of 2 to 5mm are allowed, but the distance between two adjacent defects shall not be less than 5 times the diameter of the larger defect, and the total number shall not exceed 56. 4.6.1.5 Defects with an equivalent diameter greater than 4mm are not allowed in areas with high stress (external groove deep processing 25mm, rotor center hole diameter plus 60mm for center hole).
4.6.1.6 When using 2~~2.5MHz frequency for flaw detection, the material attenuation coefficient shall be less than or equal to 4dB/m. 4.7 Center hole
4.7.1 After the final heat treatment, the center hole shall be finely bored and ground or polished in a way that does not cover defects. The surface roughness Ra is 3.21m. 4.7.2 The inner hole surface shall be inspected with a periscope. The inner surface shall not have cracks, scales, residual parts of shrinkage cavities, defects with a length exceeding 5mm1079
JB/T 7026 93
, and small defects gathered in a large area. The regulations are as follows: The number of small defects with a length of 0.5 to 1.5mm gathered in an area of 60cm2 shall not exceed 10. The number of scattered defects with a length of 1.5 to 3mm shall not exceed 10. The number of defects with a length of 3 to 5mm shall not exceed 5. The number of point defects with a length of 0.5 to 1.5mm on the entire center hole surface shall not exceed 25, and defects distributed in a chain shape are not allowed. The total number of the above defects shall not exceed 30. 4.7.3 Larger defects can be partially repaired (by boring and grinding), but the repair depth shall not exceed 5mm. After obtaining the consent of the purchaser, the center hole can be expanded.
4.8 Hardness
The hardness of forgings should be measured after heat treatment to check its uniformity. The absolute value of hardness is for reference only. The hardness deviation is stipulated as follows: the hardness deviation of the forgings should not exceed 30 Brinell hardness units when measuring 4 points (12 points in total) on the two shaft diameters and shaft body at 90° intervals. The hardness deviation of the 4 points should not exceed 40 Brinell hardness units in the axial direction of the forging. 4.9 Magnetic properties
The magnetic properties of forgings shall not be less than the following requirements:2. 5X103A/m
5. 0X103A/m
10.0×10°A/m
15.0X103A/m
20.0X103A/m
50.0×10A/m
4.10 Surface quality
B≥1.60T
.B21.72T
B≥1.80T
There shall be no cracks, folds, residual black skin that affects quality inspection, and other defects that seriously affect the performance of forgings on the surface of forgings. Local defects can be removed, and the depth of removal shall not exceed 75% of the finishing allowance. 4.11 Straightness
When the length of the forging is less than or equal to 8.5m, the center hole axis straightness tolerance value is within the cylinder with a diameter of 4mm; when the length of the forging is greater than 8.5m, the center hole axis straightness tolerance value is within the cylinder with a diameter of 5mm. 5 Inspection rules and test methods
5.↑Chemical analysis
5°1.1°Chemical analysis sampling method shall be carried out in accordance with GB222, and chemical analysis method shall be carried out in accordance with GB223. .5.1.2 Finished product analysis samples shall be taken from the longitudinal test samples of the mechanical properties of the forgings, and may also be taken from the radial test samples. 5.2 Mechanical properties inspection of forgings
5.2.1 Mechanical properties test samples of forgings
5.2.1.1 Tangential test samples
The test rings are cut from the two ends of the shaft body at a radius of about 1/3 of the shaft body surface. The supplier takes samples at the end of the steel ingot with poor quality, and the buyer takes samples at the blade end of the steel ingot.
Cut 2 tensile specimens and 2 impact specimens at two symmetrical positions on the same diameter of the ring. 5.2.1.2 Longitudinal specimens
Take 2 tensile specimens and 2 impact specimens at both ends of the forging. For forgings with center holes, take samples at 1/2 of the wall thickness, and for forgings without center holes, take samples at 1/3 of the radius from the surface. 5.2.1.3 Radial specimens
Cut 2 radial tensile specimens according to the requirements of the drawings. The positions can be at a distance of not less than 1/4 of the full length of the shaft body from the two end faces, or they can be cut on the tangential test ring.
JB/T 7026--- 93
5.2.2 The tensile test shall be carried out in accordance with the provisions of GB223. According to the provisions of GB6397, a specimen with a diameter of 10mm and a gauge length of 5 times the diameter shall be used. For radial specimens, a specimen with a diameter of 5mm and a gauge length of 5 times the diameter shall be taken. The impact test is carried out in accordance with GB229, using a 10mm×10mm×55mm test specimen.
5.3 Residual stress test should be carried out by ring cutting method or ring core resistance strain method. 5.3.1 The ring cutting method is to cut a 25mm×25mm ring at the same end of the mechanical performance test, and calculate the residual stress by measuring the average deformation of the ring before and after cutting.
The residual stress calculation formula is:
Wu Zhong: a
Residual stress, MPa;
Algebraic value of diameter increment, mm;
I)…··Outer diameter of the ring before cutting, mm;
Elastic modulus of the material, MPa
α=E8/D
When the residual stress is unqualified, the forging is supplemented with tempering. The tempering temperature should be 20~50℃ lower than the last tempering temperature of the forging. 5.4 Pickling or magnetic particle inspection
5.4.1 Pickling inspection
The surface roughness R of the pickling inspection is 0.8um. When pickling, use 15% ammonium persulfate first, and then use 10% nitric acid aqueous solution. Two inspections are carried out after pickling, the first inspection is 10 minutes after pickling, and the second inspection is not less than 12 hours after pickling. 5:4.2 Magnetic particle inspection is carried out in accordance with JB/ZQ6101. 5.5 Ultrasonic flaw detection is carried out in accordance with JB1581.
5.6 Hardness test is carried out with reference to GR231, using Brinell hardness tester or hand hammer hardness tester. 5.7 Magnetic property measurement
The purchaser shall measure the magnetic properties of forgings. Unless otherwise specified by the purchaser, it shall be carried out in accordance with JI3/ZQ6157 method. Take a magnetic property sample on the tangential test ring of the shaft body, and its size shall be determined according to the equipment of each factory. 5.8 Retest and reheat treatment
5.8.1 When the mechanical property test results do not meet the specified requirements, retesting is allowed. 5.8.2 If the test result of one specimen is unqualified, two specimens adjacent to the specimen shall be taken on the forging for retesting. However, if the specimen fails due to one point or crack, retesting is not allowed. In the retest results, both specimens must meet the specified requirements. 5.8.3 If any mechanical property test of the forging still fails to meet the retest, the supplier may reheat treat the forging, but not more than 3 times (excluding the number of re-ignition). The forging after reheat treatment shall be resubmitted for acceptance as a new forging. 6 Acceptance and certificate of conformity
6.1 The technical inspection department of the supplier shall inspect the forgings step by step according to the test methods specified in Chapter 5 of this standard, and the inspection results shall meet the technical requirements specified in Chapter 5.
6.2 After the forgings are accepted by the supplier, if unacceptable defects are found during the re-inspection of the purchaser and during the processing, they shall be returned. 6.3 The forgings shall be delivered with a certificate of conformity containing the following contents: a.
Contract number:
Order drawing number:
Standard and forging grade;
Smelting furnace number and steel grade:
Test results of spare items required by the order;
Delivery heat treatment status
7 Marking and packaging
7.1 The supplier shall stamp the manufacturer's name or logo, contract number, melting furnace number and forging 1081 on the end face of each forging equivalent to the lower end face of the steel ingot
JB/T7026
The center hole of each forging shall be coated with rust preventive agent and plugged with a wooden plug to avoid 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 Deyang Large Castings and Forgings Research Institute. The main drafters of this standard are Jiang Xinliang, Xuan Pinfan, Chen Yuqian and Liu Xiaoguang.3 Radial specimens
Two radial tensile specimens shall be cut according to the requirements of the drawing. The position may be at a distance of not less than 1/4 of the full length of the shaft body from the two end faces, or may be cut from the tangential test ring.
JB/T 7026--- 93
5.2.2 The tensile test shall be carried out in accordance with the provisions of GB223. According to the provisions of GB6397, a specimen with a diameter of 10mm and a gauge length of 5 times the diameter shall be used. For the radial specimen, a specimen with a diameter of 5mm and a gauge length of 5 times the diameter shall be taken. The impact test shall be carried out in accordance with the provisions of GB229, using a 10mm×10mm×55mm plum specimen.
5.3 The residual stress test shall be carried out by the ring cutting method or the ring core resistance strain method. 5.3.1 The ring cutting method is to cut a 25mm×25mm ring from the same end of the mechanical performance test, and calculate the residual stress by measuring the average deformation of the ring before and after cutting.
The residual stress calculation formula is:
Wu Zhong: a
Residual stress, MPa;
Algebraic value of diameter increment, mm;
I)…··Outer diameter of the ring before cutting, mm;
Elastic modulus of the material, MPa
α=E8/D
When the residual stress is unqualified, the forging is supplemented with tempering. The tempering temperature should be 20 to 50°C lower than the last tempering temperature of the forging. 5.4 Pickling or magnetic particle inspection
5.4.1 Pickling inspection
The surface roughness R of the pickling inspection is 0.8um. When pickling, use 15% ammonium persulfate first, and then use 10% nitric acid aqueous solution. After pickling, two inspections are carried out, the first inspection is 10 minutes after pickling, and the second inspection is not less than 12 hours after pickling. 5:4.2 Magnetic particle inspection shall be carried out in accordance with JB/ZQ6101. 5.5 Ultrasonic flaw detection shall be carried out in accordance with JB1581.
5.6 Hardness test shall refer to GR231 and be carried out with Brinell hardness tester or hand hammer hardness tester. 5.7 Magnetic property measurement
The purchaser shall carry out magnetic property measurement on forgings in accordance with JI3/ZQ6157 method unless otherwise specified by the purchaser. Take a magnetic property sample on the tangential test ring of the shaft body, and its size shall be determined according to the equipment of each factory. 5.8 Retest and reheat treatment
5.8.1 When the mechanical property test results do not meet the specified requirements, retesting is allowed. 5.8.2 If the test result of one sample is unqualified, two samples shall be taken from the adjacent position of the sample on the forging for retesting. However, if the sample fails due to one point or crack, retesting is not allowed. In the retest results, both samples must meet the specified requirements. 5.8.3 If any mechanical property test of the forging still fails to meet the requirements after retest, the supplier may reheat treat the forging, but not more than 3 times (excluding the number of re-heating). The forging after reheat treatment shall be resubmitted for acceptance as a new forging. 6 Acceptance and Certificate of Qualification
6.1 The supplier's technical inspection department shall inspect the forgings step by step according to the test methods specified in Chapter 5 of this standard, and the inspection results shall meet the technical requirements specified in Chapter 5.
6.2 After the forgings are accepted by the supplier, if unacceptable defects are found during the re-inspection of the purchaser or during the processing, they shall be returned. 6.3 The forgings shall be delivered with a certificate of conformity containing the following contents: a.
Contract number:
Order drawing number:
Standard and forging grade;
Smelting furnace number and steel grade:
Test results of spare items required by the order;
Delivery heat treatment status
7 Marking and packaging
7.1 The supplier shall stamp the manufacturer's name or logo, contract number, melting furnace number and forging 1081 on the end face of each forging equivalent to the lower end face of the steel ingot
JB/T7026
The center hole of each forging shall be coated with rust preventive agent and plugged with a wooden plug to avoid 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 Deyang Large Castings and Forgings Research Institute. The main drafters of this standard are Jiang Xinliang, Xuan Pinfan, Chen Yuqian and Liu Xiaoguang.3 Radial specimens
Two radial tensile specimens shall be cut according to the requirements of the drawing. The position may be at a distance of not less than 1/4 of the full length of the shaft body from the two end faces, or may be cut from the tangential test ring.
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5.2.2 The tensile test shall be carried out in accordance with the provisions of GB223. According to the provisions of GB6397, a specimen with a diameter of 10mm and a gauge length of 5 times the diameter shall be used. For the radial specimen, a specimen with a diameter of 5mm and a gauge length of 5 times the diameter shall be taken. The impact test shall be carried out in accordance with the provisions of GB229, using a 10mm×10mm×55mm plum specimen.
5.3 The residual stress test shall be carried out by the ring cutting method or the ring core resistance strain method. 5.3.1 The ring cutting method is to cut a 25mm×25mm ring from the same end of the mechanical performance test, and calculate the residual stress by measuring the average deformation of the ring before and after cutting.
The residual stress calculation formula is:
Wu Zhong: a
Residual stress, MPa;
Algebraic value of diameter increment, mm;
I)…··Outer diameter of the ring before cutting, mm;
Elastic modulus of the material, MPa
α=E8/D
When the residual stress is unqualified, the forging is supplemented with tempering. The tempering temperature should be 20 to 50°C lower than the last tempering temperature of the forging. 5.4 Pickling or magnetic particle inspection
5.4.1 Pickling inspection
The surface roughness R of the pickling inspection is 0.8um. When pickling, use 15% ammonium persulfate first, and then use 10% nitric acid aqueous solution. After pickling, two inspections are carried out, the first inspection is 10 minutes after pickling, and the second inspection is not less than 12 hours after pickling. 5:4.2 Magnetic particle inspection shall be carried out in accordance with JB/ZQ6101. 5.5 Ultrasonic flaw detection shall be carried out in accordance with JB1581.
5.6 Hardness test shall refer to GR231 and be carried out with Brinell hardness tester or hand hammer hardness tester. 5.7 Magnetic property measurement
The purchaser shall carry out magnetic property measurement on forgings in accordance with JI3/ZQ6157 method unless otherwise specified by the purchaser. Take a magnetic property sample on the tangential test ring of the shaft body, and its size shall be determined according to the equipment of each factory. 5.8 Retest and reheat treatment
5.8.1 When the mechanical property test results do not meet the specified requirements, retesting is allowed. 5.8.2 If the test result of one sample is unqualified, two samples shall be taken from the adjacent position of the sample on the forging for retesting. However, if the sample fails due to one point or crack, retesting is not allowed. In the retest results, both samples must meet the specified requirements. 5.8.3 If any mechanical property test of the forging still fails to meet the requirements after retest, the supplier may reheat treat the forging, but not more than 3 times (excluding the number of re-heating). The forging after reheat treatment shall be resubmitted for acceptance as a new forging. 6 Acceptance and Certificate of Qualification
6.1 The supplier's technical inspection department shall inspect the forgings step by step according to the test methods specified in Chapter 5 of this standard, and the inspection results shall meet the technical requirements specified in Chapter 5.
6.2 After the forgings are accepted by the supplier, if unacceptable defects are found during the re-inspection of the purchaser or during the processing, they shall be returned. 6.3 The forgings shall be delivered with a certificate of conformity containing the following contents: a.
Contract number:
Order drawing number:
Standard and forging grade;
Smelting furnace number and steel grade:
Test results of spare items required by the order;
Delivery heat treatment status
7 Marking and packaging
7.1 The supplier shall stamp the manufacturer's name or logo, contract number, melting furnace number and forging 1081 on the end face of each forging equivalent to the lower end face of the steel ingot
JB/T7026
The center hole of each forging shall be coated with rust preventive agent and plugged with a wooden plug to avoid 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 Deyang Large Castings and Forgings Research Institute. The main drafters of this standard are Jiang Xinliang, Xuan Pinfan, Chen Yuqian and Liu Xiaoguang.
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