This standard specifies the dimensions, shape, weight, allowable deviations, technical requirements, test methods, inspection rules, packaging, markings, and quality certificates of high-quality carbon structural steel hot-rolled or forged. This standard applies to high-quality carbon structural steel bars with a diameter or thickness not exceeding 250 mm. After consultation between the supply and demand parties, high-quality carbon structural steel bars with a diameter or thickness greater than 250 mm can also be provided. The grades and chemical composition specified in this standard are also applicable to steel ingots, billets, and their products 2. The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. At the time of publication of this standard, all versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T 222-1984 Sampling Methods for Chemical Analysis of Steel Samples and Permissible Deviations for Chemical Composition of Finished Products GB/T 224-1987 Method for Determining the Depth of Decarburization Layer of Steel GB/T 226-1991 Method for Acid Corrosion Testing of Macrostructure and Defects of Steel GB/T 228-1987 Metallic Tensile Testing Method GB/T 229-1994 Metallic Charpy Notch Impact Testing Method GB/T 231-1984 Metallic Brinell Hardness Testing Method GB/T 233-1982 Metallic Top Forging Testing Method GB/T 702-1986 Hot Rolled Round and Square Steel Dimensions Appearance, Weight, and Allowable Deviations GB/T 908-1987 Dimensions of Forged Round and Square Steels - Appearance, Weight, and Allowable Deviations GB/T 1979-198o Structural Steel Macrostructure Defect Rating Chart GB/T 2101-1989 Acceptance, Packaging General provisions for markings and quality certificates GB/T 2975-1998 Sampling locations and sample preparation for mechanical properties testing of steel and steel products GB/T 4336-1984 Photoelectric emission spectroscopy analysis methods for carbon steel and medium and low alloy steel GB/T 6397-1986 Metal tensile test specimens GB/T 7736-1987 Ultrasonic inspection methods for microstructure and defects of steel GB/T 10561-1989 Microscopic evaluation methods for non-metallic inclusions in steel GB/T 17616-1998 Steel and alloy product grades Unified numerical code GB/T 13299-1991 Method for evaluating the microstructure of steel GB/T 15711-1995 Method for acid immersion inspection of tower shaped hair lines in steel GB/T 17505-1998 General technical requirements for delivery of steel and steel products YB/T 5148-1993 Method for determining the average grain size of metals
Function of testing report:
1. Project bidding: Issue authoritative third-party CMA/CNAS qualification report
2. Online e-commerce platform entry: Quality inspection report recognized by major e-commerce platforms 3. Used as a sales report: issuing legally effective testing reports to make consumers more confident 4. Papers and research: Provide professional personalized testing needs 5. Judicial services: providing scientific, fair, and accurate testing data 6. Industrial problem diagnosis: Verify the troubleshooting and correction of industrial production problemsBaijian and testing process:
1. Telephone communication and confirmation of requirements
2. Recommend solutions and confirm quotations 3. Mail samples and arrange testing 4. Progress tracking and result feedback 5. Provide reports and after-sales service 6. If urgent or priority processing is requiredTesting and testing characteristics:
1. The testing industry is fully covered, meeting different testing needs
2. Fully cover the laboratory and allocate localized testing nearby3. Engineers provide one-on-one services to make testing more accurate
4. Free initial testing, with no testing fees charged
5. Self service order delivery for free on-site sampling
6. Short cycle, low cost, and attentive service 7. Possess authoritative qualifications such as CMA, CNAS, CAL, etc 8. The testing report is authoritative and effective, and is generally used in China