This standard specifies the dimensions, shape, technical requirements, test methods, inspection rules, packaging, marking and quality certificates of spring steel hot-rolled thin plates. This standard applies to spring steel hot-rolled thin plates with a thickness not exceeding 4 mm. GB/T 3279-1989 Spring steel hot-rolled thin plates GB/T3279-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Hot-rolled spring steel sheet
Main content and scope of application
GB 3279-89
Generation GB3279-82
This standard specifies the dimensions, appearance, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of hot-rolled spring steel sheet.
This standard applies to hot-rolled spring steel sheet with a thickness not exceeding 4mm. 2 Reference standards GB222 Sampling method for chemical analysis of steel and allowable deviation of chemical composition of finished products GB223 Chemical analysis method for iron and alloys Determination method for depth of decarburized layer in steel Acid etching test method for low-lying structure and defects in steel GB226 GB 247 Metal tensile test method General provisions for acceptance, packaging, marking and quality certificate of steel plates and strips GB709 Dimensions, shape, weight and allowable deviations of hot-rolled copper plates and strips GB1222 Spring steel GB2975. Sampling regulations for mechanical and process performance tests of steel GB6397 Metal tensile test 3 Dimensions, shape and allowable deviations 3.1 The dimensions, shape and allowable deviations of steel plates shall comply with the provisions of GB709. 3.2 The unevenness of the steel plate shall comply with the following provisions: for steel plates with a thickness not exceeding 1.5 mm, the unevenness shall not exceed 20 mm per meter; for copper plates with a thickness greater than 1.5~4 mm, the unevenness shall not exceed 15 mm per meter. 4. Technical requirements
4.1 Grade and chemical composition
The grade and chemical composition of copper shall comply with the provisions of GB1222. 4.2 Delivery status
4.2.1 The steel plate shall be delivered in the annealed state. According to the requirements of the purchaser, it can also be delivered in other heat treatment states after agreement between the two parties. For: Annealing includes high temperature tempering,wwW.bzxz.Net
4.2.2 The steel plate shall be delivered with trimmed edges. When delivering in other edge states, it shall be indicated in the contract. 4.2.3 According to the requirements of the purchaser, the steel plate can be delivered after pickling. 4.3 Mechanical properties
4.3.1 The mechanical properties of the steel plate in the delivery state shall comply with the provisions of Table 1. Mechanical properties of grades not listed in the table shall be agreed upon by both parties. Approved by the Ministry of Metallurgical Industry of the People's Republic of China on February 16, 1989 and implemented on January 1, 1990. GB3279-89 4.3.2 For steel plates with a thickness not exceeding 0.90 mm, the elongation index is for reference. Table 1 4.4 Macrostructure 55 Si2 Mn 60 S12 Mn 60 S12 Mn A 50 Cr VA 100% Tensile Strength % MPa Not greater than Mechanical Properties Elongation. Not less than The acid-etched macrostructure of steel plates or steel products shall not have shrinkage holes, cracks or inclusions visible to the naked eye. If the supplier can ensure that the macrostructure is qualified, no inspection is required.
4.5 Decarburization
4.5.1 Silicon alloy spring steel plate--the depth of the full decarburization layer (iron body) on one side shall not exceed 3% of the nominal thickness of the steel plate, and the sum of the two sides shall not exceed 5%.
The depth of the full decarburization layer (iron body) on one side of other spring steel plates shall not exceed 2.5% of the nominal thickness of the key plate, and the sum of the two sides shall not exceed 4.5.2
4.5.3 Upon agreement between the supplier and the buyer, steel plates with a total decarburization layer (iron body plus overburden) depth of no more than 5% on each side can be supplied. 4.6 Graphite
The graphite carbon of silicon alloy spring steel plates in the delivery state shall not be greater than Grade 1. 4.7 Surface quality
4.7.1 The steel plate shall not be delaminated, and there shall be no cracks, bubbles, folds, scars or inclusions on the surface. The above defects are allowed to be removed by grinding, and the depth of grinding shall not make the steel plate less than the minimum allowable thickness. 4.7.2 The surface of the steel plate is allowed to have the following defects with a depth or height not greater than the thickness tolerance and not exceeding the minimum or maximum allowable thickness of the steel plate: generally light pitting and local deep pitting, pits, indentations, scratches and thin layers of iron oxide; the steel plates delivered after pickling are allowed to have light yellow film and insignificant rough surfaces caused by the detachment of iron oxide. According to the requirements of the purchaser, the depth of the surface defects allowed may not be greater than half of the thickness tolerance of the steel plate, and the minimum thickness of the steel plate shall be guaranteed. 5 Test methods
The inspection items, sampling methods and test methods of each batch of steel plates shall comply with the provisions of Table 2. Table 2
Inspection items
Chemical composition
Natural test
Macrostructure
Sampling quantity, pcs
1 per furnace
Sampling method
On different steel plates or plates close to steel with similar rigidity or upper steel plate part
Test method
GB6397, Test No. P01
GB 228
Inspection items
6 Inspection rules
Sampling quantity, pcs
6.1 Inspection and acceptance
The steel plates shall be inspected and accepted by the technical supervision department of the supplier. GB3279—89
Continued Table 2
Sampling method
Steel plate collapse
Test method
Micrometer or sample
Visual inspection
6.2 Batch rules
Steel plates should be inspected and accepted in batches. Each batch consists of steel plates with the same furnace number, the same thickness and the same heat treatment furnace (the same heat treatment system for continuous furnaces).
6.3 Sampling quantity and sampling requirements
6.3.1 The sampling quantity and sampling requirements for each batch of steel plates shall comply with the provisions of Table 2. 6.3.2 For each batch, take one steel plate for inspection from the upper and lower parts of a pile, and take the inspection sample at the end of the steel plate and at a distance not less than 40mm from the edge.
6.3.3 When the batch is not more than 20 sheets, one sample can be taken from each end of a steel plate for inspection. 6.4 Re-inspection
The re-inspection rules for steel plates shall comply with the provisions of GB247. 7 Packaging, marking and quality certificate
The packaging, marking and quality certificate for copper plates shall comply with the provisions of GB247. Additional remarks:
This standard was proposed by the Information and Standards Research Institute of the Ministry of Metallurgical Industry. This standard was drafted by Chongqing Special Steel Plant. The main drafters of this standard were Ding Yuqin and Li Suqin. This standard is marked with the level of GB3279-891
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