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Heavy steel open die forgings - General technical specification
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Basic data | Standard ID | GB/T 37775-2019 (GB/T37775-2019) | | Description (Translated English) | Heavy steel open die forgings - General technical specification | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | J32 | | Classification of International Standard | 77.140.85 | | Word Count Estimation | 22,268 | | Date of Issue | 2019-08-30 | | Date of Implementation | 2019-08-30 | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration | GB/T 37775-2019: Heavy steel open die forgings - General technical specification---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Heavy steel open die forgings -- General technical specification
ICS 77.140.85
J32
National Standards of People's Republic of China
General technical specification for large steel free forgings
Published on.2019-08-30
2019-08-30 Implementation
State Administration for Market Regulation
Released by the Standardization Administration of China
directory
Preface III
1 Scope 1
2 Normative references 1
3 Terms and Definitions 1
4 Order Requirements 2
5 Manufacturing process 2
5.1 Smelting and pouring 2
5.2 Forging 2
5.3 Heat treatment 3
5.4 Defect removal and repair welding 3
6 Technical requirements 3
6.1 Chemical composition 3
6.2 Mechanical properties 4
6.3 Hardness uniformity 4
6.4 Metallographic organization 5
6.5 Residual stress 5
6.6 NDT 5
6.7 Dimensional check5
7 Inspection rules and test methods 5
7.1 Chemical composition analysis 5
7.2 Mechanical properties test 6
7.3 Hardness test 10
7.4 Metallographic examination 10
7.5 Determination of residual stress 11
7.6 NDT 11
7.7 Retest 11
7.8 Reheat treatment 11
8 Acceptance and quality certificate11
8.1 Acceptance 11
8.2 Quality certificate11
9 Logo and Packaging 12
9.1 Flags 12
9.2 Packaging 12
Appendix A (Informative Appendix) Technical and Workshop Evaluation of Special Products 13
Appendix B (Normative Appendix) Forging Ratio 16
Appendix C (informative appendix) Commonly used material standards for large steel free forgings 17
Fig.1 Schematic diagram of T×T/4 sampling7
Fig.2 Schematic diagram of t×2t sampling 7
Fig. 3 Schematic diagram of sampling of solid shaft forgings 8
Fig. 4 Schematic diagram of sampling of cylindrical forgings 8
Figure 5 Schematic diagram of sampling of pie forgings (external circle enlarged) 8
Figure 6 Schematic diagram of sampling of pie forgings (increased height) 8
Figure 7 Schematic diagram of sampling of annular forgings (external circle enlarged) 9
Figure 8 Schematic diagram of sampling of annular forgings (height increased) 9
Figure 9 Sampling position relative to the main deformation direction of the forging Figure 10
Fig. 10 Sampling position relative to the product geometry of the forging Fig. 10
Table 1 Allowable deviation of chemical composition of finished products4
Table 2 Samples and number of samples for forgings6
General technical specification for large steel free forgings
1 Scope
This standard specifies the ordering requirements, manufacturing process, technical requirements, inspection rules and test methods, acceptance and quality of large steel free forgings
Quantity certificate and marking and packaging.
This standard is applicable to the order, manufacture and production of large-scale forgings such as structural steel, stainless steel, die steel, heat-resistant steel, etc. for free forging by presses and hammers.
test.
2 Normative references
The following documents are essential for the application of this document. For dated references, only the dated version applies to this article
pieces. For undated references, the latest edition (including all amendments) applies to this document.
Allowable deviation of finished chemical composition of GB/T 222 steel
GB/T 223 (all parts) Methods for chemical analysis of steel and alloys
GB/T 228.1 Tensile Test of Metallic Materials Part 1.Test Method at Room Temperature
GB/T 228.2 Tensile Test of Metallic Materials Part 2.High Temperature Test Method
GB/T 229 Charpy Pendulum Impact Test Method for Metallic Materials
GB/T 231.1 Brinell hardness test for metallic materials - Part 1.Test method
GB/T 6394 Metal Average Grain Size Determination Method
GB/T 10561 Determination of Non-metallic Inclusion Content in Steel Standard Grading Chart Microscopic Inspection Method
GB/T 13298 Metal Microstructure Test Method
GB/T 13299 Microstructure evaluation method of steel
GB/T 20066 Sampling and sample preparation method of samples for determination of chemical composition of steel and iron
JB/T 8467 Ultrasonic testing of steel forgings
NB/T 47008-2010 Carbon steel and alloy steel forgings for pressure equipment
3 Terms and Definitions
The terms and definitions defined in NB/T 47008-2010 and the following terms and definitions apply to this document. For ease of use, the list is repeated below
Certain terms and definitions in NB/T 47008-2010.
3.1
Steel forgings forged by a free forging press of more than 10MN and a free forging hammer of more than 50kN.
3.2
Shaft forgings
A solid forging whose cross-section is circular and whose axial length L is greater than its diameter D.
3.3
Shelforging of cylindrical forgings
Axisymmetric hollow forgings whose axial length L is greater than their outer diameter D.
[NB/T 47008-2010, Definition 3.1]
3.4
Ring forging ringforging
Axisymmetric hollow forgings whose axial length L is less than or equal to their outer diameter D.
[NB/T 47008-2010, Definition 3.2]
3.5
pie forging diskforging
Axisymmetric solid forgings whose axial length L is less than or equal to their outer diameter D.
3.6
bar forging
Forgings whose section is rectangular and whose length L is greater than that on both sides.
Note. Rewrite NB/T 47008-2010, definition 3.6.
3.7
Combined forging
Combining two or more forgings into one forging and forging production as one forging.
3.8
main section mainsection
Sections to determine mechanical properties.
3.9
equivalentsection equivalentsection
A section that has the same mechanical properties as the main section and is approximately equal.
4 Order Requirements
4.1 The purchaser shall state in the order contract the standards and technical conditions to be implemented, the name of the forging, the material grade, the order drawing, the order quantity, the delivery
status, inspection items and other additional requirements.
4.2 If the forgings are transferred from the manufacturer to the sub-supplier, the sub-supplier shall have corresponding production conditions and qualifications or be approved by the purchaser.
4.3 For special products, in order to verify whether the manufacturer has the ability to manufacture qualified products, you can refer to the requirements of Appendix A for evaluation, and use
The purchaser shall specify in the order contract.
4.4 If specified in the order contract or standard, the manufacturer shall prepare a manufacturing outline before the start of manufacture and submit it to the purchaser for approval. on the purchaser
After approval, no modifications may be made without the purchaser's permission. If there are deviations that do not conform to the manufacturing outline during the production process, the purchaser should be notified.
Submit a deviation request and record. For the content of the manufacturing outline, please refer to A.3.5.
5 Manufacturing process
5.1 Smelting and pouring
Steel for forgings shall be killed steel smelted by electric furnace or converter plus ladle refining furnace, or electroslag remelting can ensure the quality of steel ingots
other smelting methods.
5.2 Forging
5.2.1 The riser and nozzle of the steel ingot should have enough cutout to ensure that the finished forging has no shrinkage cavity and serious composition segregation.
5.2.2 The forgings should be forged on a forging equipment with sufficient pressure to improve the original defects of the ingot, such as solidification defects, welding, clamping.
In order to ensure the internal quality of forgings.
5.2.3 When forging with steel ingots, the forging ratio of the total drawing length of the unupset forgings shall not be less than 3.0; the upsetting forgings shall be drawn continuously for a single time
The forging ratio should not be less than 2.0, and the total drawing length forging ratio should not be less than 2.5.When forging with forging material or rolling material, the total forging ratio of drawing length shall not be less than 1.3.
The draw-length forging ratio of the large-section flange can be appropriately reduced, but it shall not be less than 1.7.If electroslag ingots are used, the forging ratio should be appropriately reduced. forging
The total forging ratio is calculated according to the method specified in Appendix B.
5.2.4 The shape and size of forgings shall meet the requirements of forging drawings and process documents. The forging process should consider the uniformity of forging and prevent
mixed crystal. Post-forging heat treatment should take into account the adverse effects of removing hydrogen and preparing the structure for final heat treatment.
5.2.5 When required by the manufacturer, the method of combined forging can be used.
5.3 Heat treatment
5.3.1 Forgings shall be heat treated in accordance with the requirements of the material standard. During the heat preservation process, the furnace temperature should be within the range of the specified temperature ±15 °C
Inside. If necessary, an external thermocouple should be placed on the surface of the forging. In the case of comprehensive consideration of the workpiece wall thickness, shape structure, size and other factors, the external
The thermocouple should be placed at the expected maximum temperature and minimum temperature of the forging.
5.3.2 If the minimum tempering temperature needs to be specified, the purchaser shall specify it in the order contract.
5.3.3 Performance After heat treatment, if the forging needs to be calibrated, the preheating temperature for hot calibration should be 40℃~60℃ lower than the tempering temperature. After calibration, it should be
The stress relief treatment is carried out at a temperature of 30°C to 50°C lower than the final tempering temperature.
5.3.4 For forgings with residual stress requirements, controlled and slow cooling methods should be used for cooling to ensure that the residual stress value is lower than
Specify requirements.
5.4 Defect removal and repair welding
5.4.1 For the local defects whose size exceeds the tolerance range, they can be ground and removed after being approved by the purchaser, and the grinding edge shall be smooth.
transition, but the cleaning depth should not exceed 75% of the machining allowance. After grinding and cleaning, magnetic particle inspection should be carried out on the grinding part according to the material standard.
testing or penetration testing to confirm that the defect has been removed.
5.4.2 If it is found that the forging defects cannot be removed by processing, the manufacturer shall not carry out repair welding without the consent of the purchaser. After obtaining the same agreement from the purchaser
Repair welding can be carried out only after the intention. Before repair welding, suitable non-destructive testing shall be carried out to demonstrate that the defect has been completely removed. If requested by the purchaser, manufacture
The party shall submit Welding Procedure Specification (WPS), Welding Procedure Qualification Report (PQR), and qualification of welding personnel.
5.4.3 After repair welding, a repair welding inspection record shall be provided, and the record shall include the hardness of the repair welding area, the relative position and size of the repair welding area, and the hot spot after welding.
content, and have traceability.
6 Technical requirements
6.1 Chemical composition
6.1.1 Melting analysis
The manufacturer shall carry out smelting analysis of each heat (each package) of molten steel, and the analysis results shall comply with the provisions of the material standards. When multiple furnaces are poured together, a single
If the composition of Baotou molten steel exceeds the provisions of material standards, the weighted average calculation method is used for calculation, and the weighted average analysis results should meet the material standards.
Provisions. See Appendix C for the commonly used material standards for large steel free forgings.
6.1.2 Finished Product Analysis
When requested by the purchaser, the manufacturer shall conduct a finished product analysis of the forgings. The analysis results of the finished product shall meet the requirements of the material standard, but allow
There are deviations specified in Table 1, and the deviations of elements not specified in Table 1 shall comply with the provisions of GB/T 222.
7.5 Determination of residual stress
The detection position of residual stress of forgings shall be agreed upon by both parties.
The method is negotiated by both parties.
7.6 NDT
The ultrasonic testing method is in accordance with the provisions of JB/T 8467.
7.7 Retest
7.7.1 Tensile test
7.7.1.1 When the test result fails to meet the specified requirements due to the failure of the testing machine or the incorrect preparation of the sample, the test sample shall be taken again.
Do the test.
7.7.1.2 If a certain test result in the tensile test is unqualified, double samples can be taken from adjacent parts of the original sample for retest.
The results should all meet the specified requirements.
7.7.1.3 If the mechanical property test fails due to cracks and white spots in the sample, it shall not be retested.
7.7.2 Impact test
7.7.2.1 V-notch impact test
If the test results of a group of impact specimens are unqualified, a group of three specimens can be re-tested from adjacent parts of the original specimen.
The arithmetic mean value should not be lower than the specified requirements, and the number of individual values lower than the specified value should not be more than two, and only one single value should be lower than the specified value.
70% of the value.
7.7.2.2 U-notch impact test
If a test result is unqualified, double samples can be taken from the adjacent parts of the original sample for re-test, and the re-test results of both samples should not be lower.
to the specified requirements.
7.8 Reheat treatment
If the test results of any one or several mechanical properties of the forgings fail to meet the requirements, the forgings are allowed to be reheated. again
The heat treatment shall be recorded in the heat treatment report. The re-heat-treated forgings shall be re-sampled and tested according to the original regulations, and the re-heat treatment shall be carried out.
The number of times must not exceed two. Unless otherwise specified, any heat treatment due to unsatisfactory mechanical property test results shall be recorded as weight
The number of new heat treatment and the number of tempering is not limited.
8 Acceptance and quality certificate
8.1 Acceptance
The purchaser has the right to select certain test items of the forgings for acceptance. During the acceptance inspection or subsequent processing or inspection, the forgings are found not
When the technical requirements specified in this standard, product material standard and order contract are met, the purchaser shall notify the manufacturer in time, and both parties shall negotiate and resolve.
8.2 Quality certificate
At the time of delivery, the manufacturer shall provide the purchaser with a quality certificate, which shall at least include the following contents;
a) contract number;
b) Implement standard number and material grade;
c) smelting method, melting furnace number and forging identification number;
d) heat treatment report (including re-heat treatment, if necessary);
e) chemical analysis report (smelting analysis and finished product analysis);
f) Mechanical properties test report;
g) Metallographic inspection report;
h) NDT report;
i) dimensional inspection report;
j) other required inspection results.
9 Logo and Packaging
9.1 Logo
9.1.1 The manufacturer shall mark according to the marking method and mark specified in the order contract to ensure the traceability of the forgings.
9.1.2 If the purchaser does not specify the marking method, the manufacturer shall mark the contract number, melting furnace number,
Card number, pattern number, manufacturer's logo, and circle with white paint.
9.1.3 The location and method of marking shall not adversely affect the final use of the forging.
9.2 Packaging
9.2.1 The cleaning, packaging and transportation of forgings shall be carried out in accordance with the provisions of the order contract. The supplier shall properly protect the surface of the forging to prevent
Damage or rust during shipping and storage.
9.2.2 During the manufacture and transportation of stainless steel forgings, contact with substances that may adversely affect the properties and integrity of the material shall be avoided.
Substances, such as. sulfur, lead, zinc, copper, mercury, aluminum, cadmium, tin, antimony, arsenic, bismuth, halogen and other low melting point metals and their alloys and compounds. Furthermore, due to
The acid chloride generated by the aging of chlorine-containing materials is a potential danger, and tapes and marking materials should be selected reasonably to avoid contact with them.
9.2.3 In the process of processing, storage, loading and unloading, packaging and transportation, direct contact between stainless steel and carbon steel materials should be avoided.
9.2.4 Before hot processing such as welding or heat treatment, foreign matter that may react or exchange substances with the surface of the forging should be removed.
Appendix A
(informative appendix)
Technical and workshop evaluation of special products
A.1 Purpose
The purpose of this appendix is to determine the capacity of the forging shop and the suitability of the forging procedure to ensure that the forging is suitable for the intended
At the same time, it can also ensure that the acceptance tests and acceptance criteria specified in this standard are representative. If the manufacturer has a certified
The production qualification certificate of a certain type of forging product can be regarded as the manufacturer passing the technical and workshop evaluation of this type of forging product.
A.2 Overview
Before the manufacturer produces forgings according to the specified manufacturing procedures, the following evaluations shall be carried out.
--- Carry out technical evaluation of forgings according to the provisions of A.3;
--- According to the provisions of A.4 for workshop evaluation.
A.3 Technical evaluation of forgings
A.3.1 Scope of application
This technical evaluation is applicable to the inspection and verification of forgings produced according to the specified manufacturing program to prove the rationality of the forgings manufacturing process and the use of
Applicability of the Conditions of Use. During the evaluation process, the properties of the forgings, especially the special requirements and detectability can be determined.
A.3.2 Evaluation report
Before purchasing, a technical evaluation report for forgings should be submitted, and the report should include all the elements or parameters specified in A.3.Forging manufacturers should
Prepare an assessment report, including at least the following.
--- Manufacturing outline;
--- Results of various tests and inspections.
For experienced manufacturers who have produced similar forgings according to the manufacturing program, the test program for checking mechanical properties, etc. can be appropriately reduced.
relevant content and supplemented with previously archived data.
A.3.3 Validity of the assessment
If the forging manufacturer changes any element or parameter that may affect the evaluation, the results of the change should be
Evaluation.
According to the evaluation results, one of the following conclusions can be drawn as to whether the technical evaluation of forgings is effective.
---The assessment continues to be valid;
--- After the supplementary inspection, the assessment continues to be valid;
--- Re-evaluation.
A.3.4 Materials
The purchaser and manufacturer shall consider material grades based on design criteria, which shall include dimensional specifications, processing and manufacturing processes, and usage.
Use conditions.
A.3.5 Manufacturing program
The forging manufacturer shall specify the main parameters that may directly affect the quality of the forging in the manufacturing program.
The manufacturing outline should list the technological processes of smelting, forging, machining, heat treatment, testing, non-destructive testing, etc. in the order of the manufacturing process.
The manufacturing outline should include the following.
---The smelting method of molten steel;
--- weight and type of ingot;
---Ingot riser, nozzle cut off;
--- the position of the forging in the ingot;
--- Forging blank drawing (indicating the total forging ratio);
--- Heat treatment outline drawing, the position of the mechanical property sample in the figure, and the position of the sample on the sample;
--- Performance heat treatment conditions.
A.3.6 Inspection of properties of forgings
The manufacturer shall carry out various tests and inspections on the forgings in accordance with the provisions of the manufacturing program to verify the internal quality of the forgings and evaluate the chemical composition of the forgings.
and mechanical properties, to ensure that the acceptance test is representative, and to ensure that the method of non-destructive testing is suitable for the shape of the forging and the various characteristics produced by the manufacturing process.
class defect.
A.3.7 Acceptance test
The data in the evaluation report should be able to determine that the acceptance test in the manufacturing program can be used to prove the quality of the forging, and the acceptance test has been taken into account.
Criteria for possible contingency in the manufacture of subsequent formal products.
A.4 Workshop Assessment
A.4.1 Scope of application
This workshop assessment is used to demonstrate that the manufacturer has sufficient capability to produce acceptable products.
A.4.2 Evaluation report
The forging manufacturer shall provide the evaluation report of the forging workshop before supplying. Workshop assessment report should include equipment, personnel and preparation, system
Create experience, etc.
A.4.3 Validity of the assessment
If the manufacturer changes or adjusts any of the elements of the workshop evaluation that may affect the technical evaluation of forgings, the manufacturer shall change and
Evaluate the possible impact of the adjustment.
According to the evaluation results, one of the following conclusions can be drawn as to whether the manufacturer's workshop evaluation report is still valid.
--- continue to be effective or expand the scope of application;
--- After the supplementary inspection, the assessment continues to be valid or the scope of application is expanded;
--- Re-evaluation.
A.4.4 Equipment
Manufacturing workshops should have equipment that meets manufacturing requirements.
The manufacturer shall provide a description of the following equipment.
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