This standard applies to cold-rolled continuously hot-dip galvanized steel sheets and strips (hereinafter referred to as steel sheets and strips) with a nominal thickness of 0.25 to 2.5 mm. GB/T 2518-1988 Continuously hot-dip galvanized steel sheets and strips GB/T2518-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Continual hot-dip zinc-coated steel sheets and strips
Continual hot-dip zinc-coated steel sheets and stripsUDC 669. 14-42
: 669.58
GB2518—88
Replaces GB2518-81
This standard applies to cold-rolled continuously hot-dip galvanized steel sheets and strips (hereinafter referred to as steel sheets and strips) with a nominal thickness of 0.25~2.5mm. The fixed-end
is supplied in flat form. The steel strip is supplied in coil form.
2 Classification and symbols
The classification and symbols of steel plates and strips shall be in accordance with the provisions of Table 1: 2. t
Classification method
According to processability
According to zinc layer
According to surface structure
Ordinary purpose
Glaze
Extra deep drawing aging
Normal flower
Small spatula
Bright-finished zinc flower
Inlaid alloy
Approved by the Ministry of Metallurgical Industry of the People's Republic of China on February 15, 1988, etc.
Implementation on July 1, 1989
Classification method
According to surface quantity
According to dimensional accuracy
Surface treatment
GB 2518-88
Continued table!
High precision
Ordinary precision
Chromic acid passivation ratio
Chromic acid purification plus oiling
2.2 Marking example: Steel plate with zinc layer weight of 275g/m, performance JY, surface structure Z, surface treatment Y, dimensional accuracy B, size 0.70mmX700mm×2000mm, is marked as: Steel plate 275-JY-ZYE-0, 70X700×2 000-GB 2518— 883 Zinc layer weightbzxZ.net
The zinc layer weight shall be in accordance with the provisions of Table 2.
Coating type
Zinc-iron alloy
Three-point test weight
(double-sided)
Not less than
Note: ①The zinc layer weight of No. 001 is less than 100 g/m, and the specific weight shall be agreed upon by both parties. 83
Blue point test minimum value
②When the buyer has no specific requirements for the weight of the zinc layer, except for the zinc alloy bond suspension, which is supplied at 120 g/m, the others are supplied at 275 g/ml.③) Upon agreement between the two parties, steel grades and steel strips for hot thick bond layers can be supplied. The steel grade and chemical composition
The steel grade and chemical composition are selected by the supplier. The chemical composition can be provided when the buyer requires it; the buyer can also specify the steel grade upon agreement between the supply and demand parties and indicate it in the contract.
5 Properties
GB2518-88
The properties of steel and steel strip shall be in accordance with the specifications of Table 3 and Table 4. Table 3
180Bending test
Bending core diameter
Trial thickness
t = 2a
Tensile strength
270--500
270~380
270~380
Elongation,
180Cold bending test
Writing core diameter
Trial thickness
Note: i) Zinc layer and bend, zinc layer is not allowed to fall off more than 5mm from the edge of the specimen, but cracks that do not expose the steel base are allowed on the surface. Pin base cold bending, crack delamination is not allowed at the bend of the specimen, tensile test, specimen gauge length Lr = 80 mm, width = 20 mm. Bao JG galvanized steel and steel strip, its tensile strength is only for final test, the minimum tensile strength value can be agreed upon by both parties, GB 2518-88
③ For steel plates and steel strips with a thickness greater than 2.0mm, the cup test stamping probe can be agreed upon by both parties③ CS galvanized steel plates and steel strips are guaranteed not to produce slip lines during deep drawing within six months after being tempered by the supplier, ① 5C galvanized steel plates and steel strips are guaranteed not to produce slip lines during deep drawing within eight years after being tempered by the supplier. Table 4
Cup test punching depth, not less than
Nominal thickness
Processing performance
Note: According to the requirements of the purchaser, when supplying the intermediate specifications of the nominal size steel plates and steel strips in Table 4, the single punching depth shall be in accordance with the provisions of the adjacent small size. 6 Dimensions and their allowable deviations
The nominal dimensions of steel plates and steel strips shall be in accordance with the provisions of Table 5. 6.1
Note: When the purchaser has special requirements, it shall be in accordance with the agreement of both parties. 6.2
D. 25~ 0. 50
Inner diameter of coil 450
The thickness allowable deviation of steel plates and steel strips shall be in accordance with the provisions of Table 6. Nominal size
0. 50 ~2. 5
700~1500
1000~6000
Inner diameter 610
Nominal purity
Advanced box thickness A
≤1200
0. 07
>1 200
GB2518-88
Thickness allowable deviation
Ordinary accuracy B
Nominal width
~1 500
≥: 0.11
Method: 3) The distance between the thickness measuring part and the edge shall not be less than 20 mm. ± 0. 06
±: 0. 11
~1 500
The maximum allowable deviation of the thickness within 30 m of the head and tail of the steel strip shall not exceed 50% of the value specified in Table 6. The maximum allowable deviation of the thickness within 20 m of the weld zone of the intermediate steel strip shall not exceed 100% of the double set value in Table 6, PT.JYJG
Consultation accuracy B
>1 200
~1 500
According to the requirements of the purchaser, when supplying the intermediate specifications of the nominal single steel plate and steel strip in Table 6, the thickness is allowed to be adjusted according to the provisions of the adjacent small size. 6.3 The allowable deviation of the width of the copper plate and steel strip shall be as specified in Table 7. Table 7
Nominal width
Allowable width error
High precision A
>1 200
6.4The allowable deviation of steel plate length shall be in accordance with the provisions of Table 8. Nominal length
>2 000
7Shape and its allowable deviation
High precision A
Allowable length error
+0. 001 5×male ring length
7.1The cutting slope of steel plate shall not exceed 1%, and the measurement method shall be in accordance with the provisions of Figure 1, ordinary precision B
Ordinary precision B
+0.003×nominal length
GB 251888
Uniformity 00
The maximum value of the insert bend of steel plate and steel strip shall be in accordance with the provisions of Table 9, and the measurement method shall be in accordance with the provisions of Figure 2. 7.2
Maximum value of knife bend
0. 003×nominal length
Measured length
Nominal length
7.3The unevenness of the steel plate per meter shall be in accordance with the provisions of Table 10: During inspection, place the steel plate on the platform and measure the maximum distance between the lower surface of the steel plate and the platform.
Roughness, not more than
Ring width
>1 200
8 Surface structure and surface quality
Advanced grade A
Ring thickness
0. 70~<1. 2
The surface structure of the zinc layer shall be in accordance with the provisions of Table 11: 8.1
Ordinary
Surface separation
Normal zinc flower
Small zinc flower
Bright zinc flower
Ferroalloy
GB 2518--88
The zinc spangles are made by normal cold twisting speed. The cooling speed is specially controlled
The size of zinc spangles is smaller than normal zinc spangles
The small spangles are treated by skin finishing
The coating on the base metal is composed of zinc-iron alloy, without any rust. Generally, the surface quality of steel plates and strips shall be in accordance with the provisions of Table 12. 8.2
Surface uniformity
Whole flower
Stop band zinc dragon
Small zinc flower
Imperial iron
Zinc layer grade
General purpose
Suitable for painting and other purposes where normal zinc cannot meet the requirements
Suitable for deep drawing and ultra-deep drawing plus 1 and high surface finish requirements
Suitable for some options for direct painting, no pretreatment is required before painting (except for the usual
cleaning
Surface quality
Appearance is consistent with the surface quality, without any surface defects, slight scratches and indentations are allowed, and uneven zinc flowers are allowed to have small nodules and uneven zinc flowers. In addition to the surface defects allowed, cracks not exceeding 1mm, local slight zinc layer rust, slight peeling and slight galvanized thick edges not exceeding 20mm in width and slight pitting caused by rust spots on the original plate are allowed. The appearance is uniform in color, and slight scratches, indentations and chromate passivation spots are allowed. The outer specification allows uneven color and slight scratches, indentations and chromate passivation spots. Note: ① Unless otherwise agreed by both parties, only one side is checked. ② Individual abnormal parts are allowed in the steel strip. When the purchaser requires, the defect names recorded in the production process can be provided for reference. 8.3 The combination of processing performance and surface structure shall be in accordance with the specifications in Table 13. Fixed. Engineering performance
Normal front flower Z
GB2518—88
Surface structure
Small zinc flower x
Note: ①When the buyer has no requirements for the surface structure, the normal zinc flower will be supplied. ③②The symbol △ in the table indicates that there is a product.
9Surface treatment
Bright zinc flower GZ
Zinc-iron alloy XT
The surface is prone to white rust due to transportation and short-term storage. The buyer can choose one of the following surface treatment methods and indicate it in the contract. If the buyer has no requirements, the chromic acid passivation treatment will be supplied. Day, chromic acid passivation:
b. Oiling:
c. Chromic acid passivation plus oiling.
10Acceptance
10-1 The acceptance rules for steel plates and steel strips shall be in accordance with the provisions of GB217--88&General provisions for acceptance, packaging, marking and quality certification of steel plates and steel strips.
10.2 Steel plates and steel strips shall be accepted in batches. Each batch consists of copper plates or steel strips with the same steel grade, the same zinc layer weight, the same processing performance, the same size, the same surface structure, and the same surface quality. The weight of each batch of steel plates shall not exceed 10t. Each roll of steel strip is a batch. Take one piece of steel plate from each batch, and cut one piece from the head or tail of each roll of steel strip to test the performance. 10.3 The inspection items shall be in accordance with the provisions of Table 14.
Processing performance
Note: The symbol \V\ in the table indicates a necessary item. 10.4 The sampling location shall be in accordance with the provisions of Figure 3.
Zinc layer quality
CB 2518-88
Rolling direction
1—Copper base tensile test; 2—Steel base cold side test; 3—Zinc layer bending test, 4—Copper base cupping test; 5—Front layer weight testTest method shall be in accordance with the provisions of Table 15,
Inspection items
Total weight of zinc
Method
GB 2975—82
GB2975—82
GB 2975—82
Test method
GB 228-87
GB 232—82
0B 4156— 84
GB1839—80
GB23282
Test after zinc removal
Test after zinc removal
Sample width 80±5 mm
Area of ​​each sample 50ctn
Test results shall be determined according to Table 3
Thickness of steel plates and strips shall be measured with a dry ruler or caliper, and width, length, cutting slope, insert bend and unevenness shall be measured with a detailed plate, 10.6
caliper or ruler
10.7 The appearance of steel plates and strips shall be inspected with the naked eye. 11 Packaging, marking and quality certificate
The packaging, marking and quality certificate of steel plates and steel skirts shall comply with the provisions of GB 247—88, with additional remarks:
This standard was drafted by Wuhan Iron and Steel Company and the Information Standard Research Institute of the Ministry of Metallurgical Industry. The main drafters of this standard are Ke Shixuan and She Xuewen. GB2518-88Y
Difficulty level marking of this standard
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