This standard specifies the dimensions, shape and allowable deviation, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of carbon tool steel hot-rolled steel plates. This standard is applicable to carbon tool steel hot-rolled steel plates with a thickness of 0.7mm to 15mm. GB/T 3278-2001 Carbon tool steel hot-rolled steel plates GB/T3278-2001 Standard download decompression password: www.bzxz.net

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National Standard of the People's Republic of China
GB/T 3278—2001
Hot-rolled carbon tool steel sheets and plates
Hot-rolled carbon tool steel sheets and plates2001-09-15Promulgated
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
Implementation on 2002-02-01
GB/T 3278--.2001
This revision of the standard modifies the following major technical contents: Permissible deviation of chemical classification of finished products;
Qualified level of spheroidized structure;
Depth of decarburized layer of thick steel plates.
This standard replaces GB/T3278—1982 "Hot-rolled carbon tool steel sheets and plates" from the date of implementation. This standard is proposed by the State Metallurgical Industry Bureau. This standard is under the jurisdiction of the National Technical Committee for Steel Standardization. This standard was drafted by Chongqing Special Steel Company and Metallurgical Industry Information Standard Research Institute. The main authors of this standard are Xie Jinghong, Huang Ying, Xu Maojun, Qian Fugen and Deng Xian. This standard was first issued on July 9, 1982. 1 Scope
National Standard of the People's Republic of China
Carbon Tool Steel Hot-rolled Steel Sheets
Hot-rolled carhan tool steel sheets and piatesGB/T 3278—2001
Replaces GL/T 3278—1982
This standard specifies the dimensions, shape and allowable deviation, technical requirements, test methods, inspection rules, packaging, marking and quality certificates of carbon tool steel hot-rolled steel sheets.
This standard is applicable to carbon tool steel hot-rolled steel sheets with a thickness of 0.7mm15mm. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. At the time of publication of this standard, the versions shown are valid. All standards are subject to revision, and parties using these standards should explore the possibility of using the latest versions of the following standards. Sampling methods for chemical analysis of steel and allowable deviations of chemical composition of finished products GB/T 222-1984
GB/T 224--1987
Method for determination of the depth of decarburization layer in steel
GB/T2310-1984Method for testing Brinell hardness of metals GB/T247-1997General provisions for acceptance, packaging, marking and quality certification of steel plates and strips GB/T 709-1988
Dimensions, shape, weight and allowable deviations of hot-rolled steel plates and strips GB/T1298-1986
GB/T 13298-1991
Technical conditions for carbon tool steels
Methods for examination of metal microstructures
GB/T 13302 -1991
3 Dimensions, shape and allowable deviation
3.1 Dimensions and allowable deviation
Microscopic evaluation method of carbon in steel
The dimensions and allowable deviation of steel plates shall comply with the provisions of GB/T709. 3.2 Shape
The unevenness of steel plates shall not be greater than that specified in Table 1. Table 1
Nominal height
4 Technical requirements
4.1 Grade and chemical composition
Measurement length
4.1.1 The grade and chemical composition (melting analysis) of steel shall comply with the provisions of GB/T1298. 4.1.2 The allowable deviation of the chemical composition of the finished steel plate shall comply with the provisions of Table 2 in GB/T222-1984. 4.2 Delivery status
Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on 200109-15 Roughness
Implementation on 2002-02-01
GB/T 3278-2001
4.2.1 The steel plate shall be delivered in the annealed state. The steel plate may also be delivered in other states upon agreement between the supplier and the buyer. 4.2.2 The steel plate shall be delivered after leveling and trimming, and may also be delivered with rounded corners upon agreement by the buyer. 4.2.3 According to the buyer's requirements and specified in the contract, the steel plate may be delivered after pickling. 4.3 Hardness
4.3.1 The hardness of the steel plate in the annealed state shall comply with the provisions of Table 2. According to the requirements of the buyer, after the agreement between the supplier and the buyer, steel plates with lower hardness values ​​than those listed in Table 2 can be supplied,
T?.T7A,T3,T8A,T8Mn
T9.T9A.T10.T10A
Tt1,Tt1A.T12,T12A,T13,T13A
Brinell hardness HBS is not less than
4.3.2 For steel plates with a thickness not exceeding 1.5mm, the hardness may not be checked, but a tensile test shall be performed for reference. 4.4 Microstructure
4.4.1 Annealed structure
4.4.1.1 The spheroidized structure of the plate in the annealed state shall be not more than Grade 1, and shall be evaluated according to the first rating chart attached to GB/T 1298. The spheroidized structure of the steel plate used for manufacturing measuring tools and cutting tools is level 2 to 1 (and specified in the contract), and graphite carbon should not be present. 4.4.1.2 With the consent of the purchaser, the annealing structure may not be used as an assessment condition, for reference only. 4.4.2 Network carbide
4.4.2.1 The network carbide of the steel plate should not be greater than level 3. And it shall be assessed according to the second rating chart attached to GB/T1298. With the agreement between the supply and demand parties, steel plates with network carbides not greater than level 2 can be supplied. 4.4.2.2 For T7, T7A, T8, T8A, and T8Mn steel plates, if the supplier can ensure that the remaining broken network carbides are qualified, no inspection is required. 4.4.2.3 The network carbides of steel plates delivered in hot-rolled state are not inspected. 4.4.3 Decarburization layer
4.4.3.1 The depth of the total decarburization layer (ferrite) of thin steel plates shall not exceed 3% of the nominal thickness of the plate on one side, and the sum of the two sides shall not exceed 5%. Upon agreement between the supplier and the buyer, steel plates with a total decarburization layer (ferrite plus over-plating) depth of not more than 5% of the nominal thickness of the steel plate on one side may also be supplied. 4.4.3.2 The total decarburization layer depth of thick steel plates on one side shall not exceed 8% of the nominal thickness of the steel plate. 4.5 Surface quality
4.5.1 The steel plate shall not have delamination, and there shall be no bubbles, inclusions, scars and cracks on the surface. If there are the above defects, it is allowed to remove them by grinding, but the minimum thickness allowed for the steel plate shall be guaranteed.
4.5.2 The surface of the steel plate is allowed to have the following defects whose depth or height is within the thickness tolerance range and shall not make the steel plate exceed the minimum thickness allowed: - slight pitting and local deep pitting, pits, indentations, scratches. A thin layer of iron oxide scale which does not hinder the inspection of surface defects and a light yellow film after pickling, as well as an inconspicuous rough surface caused by the shedding of iron oxide scale, are allowed. 5 Test method
The inspection items, sampling quantity, sampling location and test method of a batch of steel plates shall comply with the provisions of Table 3. Table 3
Inspection items
Chemical composition
Annealing hardness
Microstructure
Graphite carbon
Decarburized layer
Surface quality
Sampling quantity and location
One for each furnace tank GB/T 222
One at each end of each steel plate for inspection
One at each end of each steel plate for inspectionOne at each end of each steel plate for inspectionOne at each end of each steel plate for inspectionTest method
GB/T1298
GB/T231
GB/T 13298
GB/T13302
GB/T 224
Micrometer, sample
6 Inspection rules
6.1 Inspection and acceptance
GB/T 3278 --2001
The inspection and acceptance of steel plates shall be carried out by the supplier's technical supervision department. The purchaser has the right to conduct inspection and acceptance according to this standard when necessary. 6.2 Batch rules
6.2.1 Steel plates shall be inspected in batches. Each batch of steel plates shall consist 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).
6.2.2 Two inspection steel plates shall be selected from each batch of steel plates, one from the upper and lower (or middle) of a pile. When the batch of thin steel plates is not more than 20 sheets, one inspection steel plate shall be selected from the upper part of a pile of steel plates. 6.3 Sampling quantity and sampling location
The number of specimens and sampling location for steel plate inspection shall comply with the provisions of Table 3, 6.4 Re-inspection and determination rules
The re-inspection and determination rules for copper plates shall comply with the provisions of GB/T 247. Packaging, marking and quality certificate
The packaging, marking and quality certificate of steel plates shall comply with the provisions of GB/T247. GB/T 3278-2001
National Standard of the People's Republic of China
Carbon Tool Steel Hot-rolled Steel Plate
GB/T 3278—2001
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