JB/T 7030-1993 Technical Specifications for Non-magnetic Guard Ring Forgings for 300-600MW Turbogenerators JB/T7030-1993 Standard Download Decompression Password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
300-600MW Steam Turbine Generator
Technical Conditions for Non-magnetic Retaining Ring Forgings
Subject Content and Scope of Application
JB/T7030-93
Replaces OEA.640.066-93
This standard specifies the technical requirements, test methods, acceptance rules, certificates and marks for non-magnetic retaining ring forgings of 300-600MW steam turbine generators.
This standard applies to the ordering, production and inspection of non-magnetic retaining ring forgings of 300-600MW steam turbine generators. 2 Reference standards
GB4338
GB6394
JB4010
Chemical analysis methods for steel and alloy
Method for tensile test of metals at high temperature
Method for determination of average grain size of metals
Ultrasonic flaw detection method for steel guard ring for turbine generator JB/ZQ6117
JB/ZQ6136
JB/ZQ6158
3 Ordering requirements
Method for mechanical properties test of steel products
Method for liquid penetrant inspection
Method for determination of magnetic permeability of weakly magnetic materials
3.1 The purchaser shall specify the adopted standards, grade of forgings, steel grade, corresponding technical requirements and inspection items, as well as other additional instructions in the order contract or order agreement.
3.2 When placing an order, the purchaser must provide the supplier with a rough machining drawing (finishing dimensions if necessary), and the sample location should also be marked on the drawing and marked as follows:
Forging grade × Standard number
4 Technical requirements
4.1 Manufacturing
4.1.1 Smelting
Steel for forgings should be smelted in an electric furnace and an electroslag remelting furnace. 4.1.2 Head and tail cutting
The upper and lower ends of the steel ingot for forgings should be sufficiently cut off to ensure that the forgings have no shrinkage cavities and unacceptable segregation. 4.1.3 Forging
4.1.3.1 Forging should ensure that the entire cross-section of the forging is fully forged. 4.1.3.2 Deformation strengthening should be carried out at room temperature or slightly above room temperature using appropriate strengthening methods, such as module expansion and hydraulic bulging methods. 4.1.4 Heat treatment
4.1.4.1 Forgings should be solution treated after hot forming and before deformation strengthening. Approved by the Ministry of Machinery Industry on September 21, 1993
Implementation on July 1, 1994
JB/T7030··93
4.1.4.2 After deformation strengthening, forgings should be stress relieved. 4.1.4.3 The stress relief annealing process should be heated to 330~355 (at a rate of no more than 40C/h, maintained at this temperature for 10~12h, and then cooled at a rate of no more than 40C/h to ensure dimensional stability. 4.1.5 Mechanical processing
Forgings should be rough machined before deformation strengthening. Forgings shipped must be machined to the size and surface roughness indicated on the purchaser's drawings. 4.2 Chemical composition
The chemical composition of the pot used for forgings shall comply with the provisions of Table 1 . Table!
1Mn18Cr18N
IMn18Cr18N
Mechanical properties
17.50-20.00
Chemical composition
17.50~20.00
The mechanical properties of forgings shall conform to the provisions of Table 2. Table 2
970~1100
≥102
Test temperature
Analysis for reference
Mechanical properties|| tt||1030~1170
.ou..8：95105;Ak：2027
4.3.2 On the same test ring, the fluctuation value of the tensile strength or yield strength measured should not exceed 50MPa: 4.4 When the magnetic field intensity is 0.8×10°A/m, the magnetic permeability should not be greater than 13.2×10-7H/m. 4.5 Grain size
The grain size of the forging should be Grade 1 or better than Grade 1 as specified in GB6394. 4.6 Nondestructive testing
4.6.1 General requirements
1070~1210
Forgings shall be free of cracks, strip inclusions, folds and other defects that affect use. Local surface defects may be removed, and the depth of removal shall not exceed 75% of the finishing allowance.
4.6.2 Liquid penetrant inspection
It shall be carried out on all surfaces of each retaining ring. 4.6.2.2
Liquid penetrant inspection requirements are as follows:
Existence,
JB/T 7030---93
There should be no defect display (local defects can be handled according to Article 4.6.1"); the surface of the forging after fine processing I, the buyer shall conduct liquid penetration inspection, and the result is that the entire fine processing surface of the guard ring is not allowed to have any defects. Individual defects can be locally polished after the designer agrees with the wrong party. 4.6.3
Ultrasonic flaw detection inspection
Each forging shall be subjected to ultrasonic flaw detection, and the entire outer circle shall be tested by transverse wave and longitudinal wave, and the two end faces shall be tested by longitudinal wave. 4.6.3.2
The requirements for ultrasonic flaw detection are as follows:
When transverse wave flaw detection is performed, no defect signal exceeding 1/2 standard line is allowed; within the full circumference of 160mm width, within the 1/2 standard line and There shall be no more than 8 defect signals between the 1/4 standard lines, and the distance between any two adjacent defects shall not be less than 50mm. When the number of defect signals exceeds 8, the negotiation shall be recorded; c.
Retaining rings that cannot be distinguished from the noise level by the coarse grains or microstructure of the forgings are rejected; during longitudinal wave flaw detection, defects greater than 2mm in equivalent diameter are not allowed, and no more than 4 defects with an equivalent diameter of 1.6d.
~2mm are allowed within any 100mm wide full circumference;
Retaining rings with a bottom wave drop greater than 6dB compared with the bottom wave of the defective part and the intact part of the material are rejected; 4.7 Stress Corrosion Test
4.7.1 When the purchaser makes a request, a stress corrosion test shall be carried out. 4.7.2 The test time that causes stress corrosion cracking to appear shall be greater than or equal to 1000h. 4.8 Dimensions and surface roughness
The dimensions, tolerances and surface roughness of the parts shall comply with the requirements of the order drawings. 5 Inspection rules and test methods
5.1 Chemical composition analysis
5.1.1 The supplier shall conduct smelting analysis on each furnace of molten steel to determine the percentage of the elements specified in Table 1. The samples shall be taken out when the molten steel is poured. When electric melting and remelting are adopted, the smelting composition of the parent material shall prevail. 5.1.2 The buyer shall conduct finished product review analysis. The sample shall be taken from any point at the 1/2 thickness of the extended section of the forging, or from the mechanical properties sample
5.1.3 The chemical analysis composition shall be carried out in accordance with GB223 and relevant analysis methods. 5.2 Mechanical properties inspection shall be carried out in accordance with JB/ZQ6117 and with reference to GB4338. 5.2.1 Performance samples shall be cut after deformation strengthening and stress relief treatment. 5.2.2 Sampling location and quantity
5.2.2.1 According to the forging ordering drawing, the supplier and the buyer shall each cut a test ring from the extended section at one end of the forging for testing. The sampling location shall be as specified in Figure 1 and the ordering drawing
JB/T7030-93
Specimen extension part B
Tangential tension
Tangential impact
The number of specimens shall be as specified in Table 3 and the ordering drawing. Table 3
Unit name
5.2.3 Retest
Test sample location
Sampling location
Number of test samples
Permeability test sample
Test sample type
Magnetic permeability
Magnetic permeability
Number of test samples (pieces)
If the mechanical property test results do not meet the requirements, it is allowed to take the two adjacent test samples for retest. If the test fails due to cracks, retesting is not allowed. If one test sample still fails after the retest, the forging shall not be used. 5.3 Grain size determination
5.3.1 The test method shall be carried out in accordance with GB6394. 5.3.2 The grain size test sample is taken from the mechanical property test ring and measured on the radial-longitudinal section. 5.4 Ultrasonic testing
Ultrasonic flaw detection of forgings shall be carried out in accordance with JB4010, and 1/4 standard line shall be added during shear wave flaw detection. 5.5 Liquid penetrant testing
Liquid penetrant testing shall be carried out in accordance with JB/ZQ6136. 5.6 Magnetic permeability determination
The supplier and the buyer shall each take samples and carry out the test in accordance with JB/ZQ6158. 5.7 Stress corrosion test
5.7.1 Test conditions:
Bending stress
Magic corrosion medium
590MPa
36%Ca(NO,)+3%NH,NO,+61%H,O
Test temperature Room temperature
JB/T7030—93
5.7.2 The test specimens are taken at a relative position close to the inner side of the ring. Two specimens are taken. The test adopts the four-point bending constant deformation method. The stress must be loaded on the convex surface of the ring.
6 Acceptance and certificate of conformity
6.1 The forgings shall be accepted by the supplier's quality inspection department in accordance with this standard, and the buyer shall re-inspect in accordance with this standard. 6.2
The supplier shall provide the buyer's inspector with necessary convenient conditions so that the buyer's inspector can carry out his work. The buyer's factory inspector shall not cause unnecessary obstruction to the supplier's production. Unless otherwise specified, all inspections shall be carried out at the supplier (except for review and analysis tests). 6.3 The supplier shall provide the purchaser with a certificate of conformity when the forgings leave the factory. The certificate of conformity shall report the following contents: a.
Contract number, melting furnace number, standard number, order forging drawing number and grade number; melting analysis results;
Mechanical property test results;
Grain size grade;
Stress corrosion test results;bzxz.net
Magnetic permeability measurement results;
Liquid penetrant test and ultrasonic test results, including defect distribution diagram; Solution treatment and stress relief tempering temperature, holding time and strengthening method. 6.4 After the forgings are accepted by the supplier, if the purchaser finds unacceptable defects during the re-inspection and processing, the purchaser shall promptly notify the supplier and the two parties shall negotiate to resolve.
7 Marking and Packaging
The supplier shall indicate the supplier's factory name or logo, order contract number, order drawing number, smelting furnace number and forging card number on the end face of each forging nozzle
2 The surface of the forging shall be completely coated with rust inhibitor to prevent corrosion during transportation. 3 Packaging and shipment shall avoid damage to the forgings when they are transported to the purchaser. 7.3
Additional Notes:
This standard was proposed and coordinated by the Deyang Large Castings and Forgings Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Deyang Large Castings and Forgings Research Institute. The main drafters of this standard are Zhu Jiexiu, He Enxiang, Tang Qigen and Zhou Yunsong. 1091
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