Since you are asking about galvanized sheets, there is no need to introduce their uses. I wonder if it will be useful to give you a national standard.

New national standards for galvanized sheets

Published on: 2009-5-15

Galvanized standards

Foreword

1. Scope

2 Normative reference documents

3 Terms and definitions

4 Classification and codes

5 Dimensions, Appearance, weight and allowable deviation

6 Ordering content

7 Technical requirements

8 Test method

9 Inspection rules

10 Packaging, marking and quality certificate

Appendix A (normative appendix) Weight calculation method for theoretical weighing

Foreword

This standard Reference ISO 3575: 1996 "Continuous hot-dip galvanized carbon steel sheet of commercial grade, fixed forming grade and stamping grade", ISO 41996 "Continuous hot-dip galvanized carbon steel sheet of structural grade" and DIN EN 10142: 2000 "Continuous hot-dip galvanized steel sheet" Structural Steel Plate and Steel Strip

Technical Conditions", DIN 10147: 2000 "Technical Conditions for Supply of Low Carbon Steel Continuous Hot-dip Galvanized Steel Plate and Steel Strip for Cold Forming" and complied with the national standards

GB/T 2518-1998 "Continuous hot-dip galvanized steel sheets and steel strips" has been revised based on the specific circumstances.

This standard replaces GB/T2518-1998 "Continuous hot-dip galvanized steel sheets and steel strips".

Compared with GB/T2518-1998, this standard has modified the following main technical contents:

——Added normative reference documents, technical requirements, and information provided by the purchaser. , inspection, re-inspection, inspection and acceptance, etc.;

——Add hot-rolled pickled strip steel as the base material of galvanized steel plate, expanding the thickness range of the product;

—— Add content on the chemical composition of galvanized steel sheets;

——Add a series of structural grade galvanized steel sheets;

——Add a variety of zinc-free galvanized layers;

——Increase the coating classification of coating weight;

——Change the classification method of surface quality levels;

——Add three surface treatment items of paint sealing, phosphating and no treatment ;

——Cancel the provisions on the cup burst value of galvanized steel plates, and add the provisions on the n and r values.

Appendix A of this standard is an appendix to the standard.

This standard is proposed by the China Iron and Steel Industry Association.

This standard was drafted by: Wuhan Iron and Steel (Group) Company, Metallurgical Industry Information Standards Research Institute, Huangshi Shanli Coating Engineering Technology Co., Ltd.

Important drafters of this standard: Yang Dake, Liu Youren, Huang Ying, Zheng Hongdao, He Mingwen, Yang Chunfu, Zhang Caifu, Su Weijia.

The previous versions of the standards replaced by this standard are:

——GB 2518——1981, GB 2518——1988.

Galvanized steel sheets and steel strips

1 Scope

This standard specifies the allowable hot-dip galvanized steel sheets and steel strips (hereinafter referred to as steel plates and steel strips) in the coming year. ) definition, classification and code, dimensions, appearance

weight and allowable deviations, technical requirements, experimental methods, inspection rules, packaging, marking and quality certificates, etc.

This standard is applicable to continuous hot-dip galvanizing ordinary grade, mechanical engagement grade and stamping grade (03, 04 , 05, 06 grade), structural grade steel plates and steel strips.

2 Normative reference documents

The provisions in the following documents become provisions of this standard through reference in this standard. For dated referenced documents, all subsequent amendments (excluding errata content) or revisions do not apply to this standard. However, all parties that reach an agreement based on this standard are encouraged

To see if the latest versions of these files are available. For undated referenced documents, the latest edition applies to this standard.

GB/T 222-1984 Sampling methods for chemical analysis and allowable differences in chemical composition of finished products

GB/T 228 Room temperature tensile test method for metallic materials (GB/T 228 ——2002, eqv ISO 6892:1998)

GB/T 232 Bending test method for metallic materials (GB/T 232——1999, eqv ISO 7438:1985)

GB/ T 247 General provisions for acceptance, packaging, marking and quality certificates of steel plates and strips

GB/T 708 Dimensions, shapes, weights and allowable deviations of cold-rolled steel plates and strips

GB/T 709 Dimensions, shapes, weights and allowable deviations of hot-rolled steel plates and strips

GB/T 1893 Test methods for quality of hot-dip galvanized layers of steel products (GB/T 1839-1993, neq ISO 1460: 1973)

GB/T 2975 Sampling locations and sample preparation for mechanical property testing of steel and steel products (GB/T 2975-1998, eqv ISO

377: 1997 )

GB/T 4336 Spark source atomic emission spectrometry analysis method for carbon steel and medium-low alloy steel (conventional method)

GB/T 5027 Plastic strain ratio of metal sheets and strips (r value) test method (GB/T 5027-1999, eqv ISO

10113:1991)

GB/T 5028 Plastic strain of metal sheets and strips. Hardening index ( n value) test method (GB/T 5028-1999, eqv ISO

10275:1993)

GB/T 8170 Numerical rounding rules

GB /T 17505 General technical requirements for delivery of steel and steel products (GB/T 17505——1998, eqv ISO 404:1992)

3 Terms and Definitions

3.1

Connotinuous hot-dip zinc-coated steel sheets and strips

Continuous hot-dip galvanized steel sheets and strips are made on a continuous production line by cold-rolled steel strips or hot-dip galvanized steel strips. The pickled rolled steel strip is immersed in a plating bath with a zinc content (mass fraction) of not less than 98, and is a galvanized steel sheet and steel strip obtained by hot-dip plating.

3.2

Normal spagle coating

During the normal solidification process of the zinc layer, the zinc grains grow freely and form, which has an obvious spagle morphology. of plating.

3.3

minimized spangle coating

During the solidification process of the zinc layer, the zinc grains are artificially restricted to form as small a spangle as possible plating.

3.4

Spangle-free coating is obtained by adjusting the chemical composition of the plating solution and does not have a visually visible spangle morphology. Uniform coating on the surface.

3.5

zinc-iron alloy coating

The steel strip after passing through the galvanizing bath is heat treated to make the entire coating generate zinc and iron The alloy layer of this coating is dark gray in appearance, has no metallic luster, and is easily powdered during the violent molding process. It is suitable for coatings that can be painted directly without further processing except for general cleaning.

3.6

Differential coating

For both sides of the galvanized steel plate, coatings with different zinc layer weights are required.

3.7

Skin pass

Skin pass is a slight deformation of galvanized steel sheets for one or more of the following purposes of cold rolling processing.

Improve the surface appearance of galvanized steel sheets or be suitable for decorative coatings; temporarily minimize the slip lines (Lüders lines) or creases produced during processing of finished products, etc.

4 Classification and codes

4.1 The classification and codes of performance levels are as specified in Table 1.

Table 1 Performance classification and codes

Level performance level code application scope

General purpose 01

Mechanical engagement 02 Zinc layer weight The code number shall not exceed Z350

Punching 03 The thickness range is ≥0.4mm The weight of the zinc layer shall not exceed Z275

Deep drawing 04

Special killed steel deep drawing 05

No aging super deep drawing 06

Structure 220, 250, 280, 320, 350, 400, 450, 550 Steel plates with thickness <0.4mm are not suitable for 220, 250, 280 and 320 Level

4.2 The type and code of the substrate shall be as specified in Table 2.

Table 2 Types and codes of substrates

Type codes of substrates

Cold-rolled coils

Hot-rolled pickled coils H

4.3 Classification and code of coating types and coating weight

Galvanized steel sheets and steel strips are suitable for anti-corrosion purposes. The protective effect of the galvanized layer in the atmosphere is the same as that of zinc per unit area. Directly proportional to layer weight. The weight of the zinc layer should be suitable for the required service life, plate thickness and forming requirements.

4.3.1 The classification and code of double-sided equal thickness galvanized layer types and coating weights are as specified in Table 3. Upon agreement between the supplier and the buyer, steel plates and steel strips with coating weights not listed in Table 3 can also be provided.

Table 3 Classification and code of galvanized layer types and coating weight

Galvanized layer Zinc-iron alloy coating

Coating weight/(g/㎡) (double Side) Code Coating weight/ (g/㎡) (Both sides) Code

(60) (Z60) (40) (ZF40)

80 (Z80) 60 (ZF60)

100 (Z100) 80 (ZF80)

120 (Z120) 100 (ZF100)

150 (Z150) 120 (ZF120)

180 (Z180) 150 (ZF150)

200 (Z200) 180 (ZF180)

220 (Z220)

250 ??(Z250)

275 (Z2750)

350 (Z350)

450 (Z450)

600 (Z600)

Note: The weight of the zinc layer in brackets needs to be negotiated between the supplier and the buyer.

4.3.2 The differential thickness coating can be expressed as half of the coating weight listed in Table 3 for the different coating weights on the upper and lower surfaces, such as: Z40/90 Or ZF30/50. The appearance of low zinc layer weight surfaces may differ from the appearance of high zinc layer weight surfaces.

4.4 The classification and code of the surface structure of the zinc layer are as specified in Table 4.

Due to strain test marketing, the smoothed 01~04 grade steel plates and steel strips must be leveled by the user with an effective straightening machine before processing to avoid slip lines. Finished Grade 05 or 06 steel plates and strips are non-aging finish steel plates and strips, which can avoid slip lines within 6 months.

Table 4 Classification and code of zinc layer surface structure and smooth surface

Surface structure code

Not smooth and smooth

Normal Spangle N NS

Small spangle M MS

No spangle F FS

Zinc-iron alloy ZF ZFS

4.5 surface quality The classification and code are as specified in Table 5.

Table 5 Surface quality classification and code

Surface quality code

Ordinary surface FA

Higher surface FB

Advanced surface FC

4.6 The classification and code of surface treatment are as specified in Table 6.

Table 6 Classification and code of surface treatment

Surface treatment symbol

Passivation C

Oil O

Lacquer seal L

Phosphating P

No treatment U

4.6.1 Passivation

The zinc coating is passivated Treatment can reduce the occurrence of fold rust (white rust) under humid temperature storage and transportation conditions. However, the anti-corrosion properties of this chemical treatment are limited and, moreover, hinder the adhesion of most coatings. This treatment is generally not used in zinc-iron alloy coatings. In addition to smooth surfaces, as a routine, manufacturers perform passivation treatment on other types of zinc coatings.

4.6.2 Oiling

Oiling can reduce the corrosion of steel plates under humid storage and transportation conditions. Oiling steel plates and steel strips after passivation treatment will further reduce the corrosion of steel plates and steel strips. Corrosion under storage conditions. The oil layer should be removable with a degreasing agent that will not damage the zinc layer.

4.6.3 Paint sealing

By applying a very thin layer of transparent organic coating film, an additional anti-corrosion effect, especially fingerprint resistance, can be provided. Improves lubricity during molding and serves as an adhesive base for subsequent coatings.

4.6.4 Phosphating

Through phosphating treatment, galvanized steel sheets with various coating types can be coated without further treatment except for normal cleaning. This treatment can improve the adhesion and anti-corrosion properties of the coating and reduce the risk of corrosion during storage and transportation. After phosphating, it can be used with suitable lubricant to improve the molding performance.

4.6.5 Non-processing

Steel plates and steel strips supplied in accordance with this standard may not be processed only if the orderer makes a request not to process and is responsible for it. Passivation or surface treatment such as oiling, paint sealing or phosphating.

5 Dimensions, shape, weight and allowable deviations

5.1 Dimensions and allowable deviations

5.1.1 Steel plates and steel plates based on hot-rolled pickled coils The size range of steel strips should comply with the regulations of GB/T709, and the size range of cold-rolled coils as the base material should comply with the regulations of GB/T708.

5.1.2 Thickness tolerance

5.1.2.1 The thickness tolerance of steel plates and steel strips based on hot-rolled pickled coils should comply with the provisions of GB/T709.

5.1.2.2 The allowable thickness deviation of cold-rolled coils as the base material shall comply with the provisions of Table 7.

5.1.2.3 When measuring the thickness of steel plates and steel strips, the thickness of the coating should be included.

5.1.2.4 The thickness measurement location is any point not less than 25mm from the edge.

Table 7 Thickness tolerance in millimeters

Nominal width Nominal thickness

＞0.25 ≤0.4 ＞0.4≤0.6 ＞0.6≤0.8 ＞0.8≤1.0 ＞ 1.0≤1.2 ＞1.2≤1.6 ＞1.6≤2.0 ＞2.0≤2.5 ＞2.5≤3.0

＞600 ≤1200 ±0.03 ±0.04 ±0.05 ±0.06 ±0.07 ±0.08 ±0.09 ±0.11 ±0.12

＞1200 ≤1500 ±0.04 ±0.05 ±0.06 ±0.07 ±0.08 ±0.09 ±0.10 ±0.12 ±0.13

＞1500 ≤1800 — ±0.06 ±0.07 ±0.08 ±0.09 ±0.10 ± 0.12 ±0.13

5.1.2.5 The allowable thickness deviation within 30m of the total length of the head and tail of the steel strip supplied in rolls is 50% greater than the value specified in Table 7, and the allowable thickness deviation within 15m of the weld area is greater than Table 7 specifies a value greater than 60.

5.1.3 Width tolerance

The width tolerance of the substrate should comply with the provisions of Table 8.

5.1.4 Length tolerance

The length tolerance of all base materials should comply with the provisions of Table 9.

Table 8 Width tolerance in millimeters

Nominal width tolerance

Level A accuracy Level B accuracy

600~1200 5 2

＞1200~1500 6 2

＞1500 7 3

Table 9 Length tolerance in millimeters

Nominal width ( L) Allowable deviation

Level A accuracy Level B accuracy

＜2000 6 3

≥2000 0.3×L 0.15 ×L

5.2 Appearance

5.1.1 Off-square steel

The off-square degree of the steel plate shall not exceed 1 of the nominal width of the steel plate. The shadow length of the steel plate, or half the difference between the diagonal lengths of the measured steel plate.

5.2.2 Sickle bend

The sickle bend of steel plates and steel strips should comply with the requirements in Table 10.

Table 10 Allowable deviation of sickle bend in millimeters

Name Maximum measurement length of sickle bend

Steel plate 0.3×L Actual length (L)

Steel strip 5 2500

5.2.3 Unevenness

The unevenness of the steel plate should comply with the requirements in Table 11. The unevenness of the steel plate is the maximum distance between the bottom of the steel plate and the platform when the steel plate is placed freely on the platform.

Table 11 Allowable deviation of steel plate unevenness in millimeters

Performance level code Nominal thickness Allowable deviation of unevenness

Nominal width

＜ 1200 ≥1200-<1500 ≥1500

01-06

220

250 ??＜0.7 5 6 8

≥0.7-＜ 1.2 4 5 7

≥1.2 3 4 6

280

320

350 <0.7 10 12 15

≥0.7-＜1.2 8 10 13

≥1.2 6 8 11

Note: There is no unevenness deviation requirement for grades 400, 450 and 550.

5.3 The inner diameter and outer diameter (maximum value) of the steel strip supplied in rolls should be specified in the contract.

5.4 Weight

The weight of steel plates can be delivered according to actual weight or theoretical weight. See Appendix A for the theoretical weight calculation method. Steel strips are delivered according to actual weight.

6 Ordering Contents

6.1 The ordering contract or order should include the following contents:

a) Product name (plate or strip)

b) Type of steel base;

c) Standard number of this product;

d) Performance level;

e) Type and weight of coating;

f) Surface structure;

g) Surface treatment (passivation, oil coating, paint sealing, phosphating or no treatment);

h) Surface quality;

i) Specifications and quantity;

j) Dimensional accuracy.

6.2 If the following item information is not mentioned when ordering, this standard product will be processed according to conventional methods:

a) Steel base type: products with thickness ≤3.0mm, according to cold-rolled base plate Products with thickness >3.0mm are supplied as hot-rolled substrates;

b) Surface treatment: In addition to alloy coating and smooth surface, it is treated as passivation and oiling;

c) Surface structure: according to matte surface treatment;

d) Dimensional accuracy: supplied according to A-level accuracy;

e) Packaging: according to the packaging method provided by the supplier;

6.3 Marking examples:

Marking sequence: Marking number—Performance classification—Coating type—Zinc layer weight—Surface structure—Surface treatment—Steel base type—Specifications and dimensions

(1) Galvanized steel plate, mechanical engagement grade, zinc coating weight 275g/m2, normal zinc finish, surface treatment passivation and oiling, surface quality FB level; cold rolled base plate, specification is 2.0mm× The mark of 1200mm×2000mm is:

GB/T 2518-02Z75-NS-CO-FB-2.0×1200×2000

(2) Galvanized steel strip, 220 structural grade , zinc-iron alloy, zinc layer weight 180g/m2, zinc-iron alloy smooth, no surface treatment, surface quality FA grade, hot-rolled substrate, specification 2.0mm×1200mm, marking example:

GB/T 2518-220ZF180-ZFS-U-FA-H2.0×1200×C

7 Technical requirements

7.1 Production process

Production of steel plates and steel strips The process is usually chosen by the manufacturer itself.

7.2 Chemical composition

The chemical composition (smelting analysis) of steel plates and steel strips should comply with the requirements in Table 12. Analysis results should be provided when requested by the user.

Table 12 Chemical composition (smelting analysis)

Performance level chemical composition (mass fraction) not greater than

C Mn P S Ti

01 0.15 0.60 0.035 0.035

02 0.12 0.60 0.035 0.035

03 0.10 0.50 0.030 0.030

04 0.08 0.45 0.025 0.025

05 0.02 0.45 0.020 0.020

06 0.25 0.25 0.010 0.020

Structural grade 0.25 1.7 0.05 0.035 0.3

Note 1: 05 grade materials also add appropriate amounts of titanium and niobium Or vanadium.

Note 2: Grade 06 titanium can be completely or partially replaced with niobium, and the carbon and oxygen are completely solidified.

Note 3: The phosphorus content of grades above 350 is not greater than 0.20.

7.3 Zinc layer quality

The weight of the zinc layer should comply with the requirements in Table 13.

Table 13 Zinc layer weight

Coating type Coating code Minimum average value of double-sided three-point inspection/(g/m2) Minimum single-point inspection value/(g/m2)

p>

Double-sided single-sided

Zinc (Z60) (60) (51) (24)

Z80 80 68 32

Z100 100 85 40

Z120 120 102 480

Z150 150 128 60

Z180 180 153 72

Z200 200 170 80

Z220 220 187 88

Z250 250 213 100

Z275 275 234 110

Z350 350 298 140

Z450 450 383 180

Z600 600 510 240

Zinc-iron alloy (ZF40) (40) (34) (16)

ZF60 60 51 24

ZF80 80 68 32

ZF100 100 85 40

ZF120 120 102 48

ZF150 150 128 60

(ZF180) (180) (153) (72)

Note 1: There are bracketed items in the table that require agreement between the supplier and the buyer.

Note 2: Steel strips divided into wide coils can only be inspected at a single point. .

7.4 Coating adhesion

The coating adhesion should be subjected to a 180° cold bending test of the zinc layer according to the diameter specified in Table 14. The zinc layer is not allowed to fall off beyond 5mm from the edge of the bend of the specimen, but cracks in the zinc layer that do not expose the steel base are allowed to appear on the surface. The zinc-iron alloy (ZF) coating is allowed to have cracks, thickening, and powder.

Table 14 180° cold bending test of zinc layer

Performance level bending center diameter (D)

01~06 220 250 280 320, 350

Plate thickness a/mm Various thicknesses <3.0 ≥3.0 <3.0 ≥3.0 <3.0 ≥3.0 Various thicknesses

Coating Z275, ZF180 and below 0 1a 2a 1a 2a 2a 3a 3a

Z350 1a

Z450 2a 2a 2a

Z600 3a 2a 4a

7.5 Mechanical properties

7.5.1 01 The mechanical properties of ~06 grade steel plates and steel strips should comply with the requirements in Table 15. When conducting a 180° cold bending test on the steel base, cracks and delamination are not allowed to occur at the bend of the sample.

Table 15 Mechanical properties of 01~06 grade steel plates and strips

Grade zinc layer Rpc.2/(N/m㎡) Rm/ (N/m㎡) A80 mm/ R90 N90 Steel base 180° cold-formed diameter (d, transverse direction)

Plate thickness (a)

Not less than <3mm ≥3mm

1 Z — — — — — 1a 2a

ZF

2 Z — 270~500 22 — — 0 1a

ZF

3 Z 140~ 300 270~420 26 — — — —

ZF

4 Z 140~260 270~380 30 — — — —

ZF

5 Z 140~270 270~350 36 1.6 0.18 — —

ZF 34 1.4

6 Z 120~280 270~350 39 1.9 0.21 — —

ZF 37 1.7 0.2

Note 1: If the yield point is obvious, take Rel.

Note 2: The tensile test takes transverse specimens, and the tensile strength value is rounded up to 10N/mm㎡.

Note 3: When the material thickness (after removing the galvanized layer) is ≤0.7mm, the elongation value listed in the table is reduced by 2.

Note 4: When the material thickness (after removing the galvanized layer) is ≤0.7mm, the r90 value of grade 06 in the table is reduced by 0.2 and the n90 value is reduced by 0.01.

Note 5: When the material thickness (after removing the galvanized layer) is >1.5mm, the r90 value of grade 06 in the table is reduced by 0.2.

Note 6: Level 04 can also provide n90 and r90 values, and their values ??are determined by negotiation between the supply and demand parties.

Note 7: The mechanical properties of hot-rolled base materials are subject to negotiation between the supplier and the buyer.

Due to strain aging (the characteristics of increasing hardness and decreasing elongation with the extension of storage time), the mechanical properties specified in Table 15 are as shown in Table 16 for steel plates and steel strips of various performance levels. The specified applicable time period. To reduce this effect, grade 05 or 06 steel plates and strips should be used.

Table 16 Applicable time period for mechanical properties

Level 01 02 03 04 05 06

Applicable time period - 8 days, 1 month, 6 months and 6 months Month

7.5.2 The mechanical properties of structural grade steel plates and steel strips should comply with the requirements in Table 17. The 180° cold bending test of steel base is only carried out when the user has special requirements.

When conducting bending tests, cracks and delamination are not allowed to occur at the bends of the specimen.

Table 17 Mechanical properties of structural grade steel plates and strips

Grade Rpc.2/(N/m㎡) is not less than Rm/ (N/m㎡) is not less than A80 mm/ Not less than the 180° cold-formed diameter of the steel base (d, transverse direction)

Plate thickness (a)

<3mm ≥3mm

220 220 300 20 1a 2a

250 ??250 330 19 1a 2a

280 280 360 18 2a 3a

320 320 390 17 3a

350 350 420 16

400 400 470 —

500 500 530 —

550 550 560 — — —

Note 1: If the yield point is obvious, then Take ReH.

Note 2: Take the transverse sample for the tensile test, and the tensile strength value (for reference only) is rounded up to 10N/m㎡.

Note 3: When the material thickness (after removing the galvanized layer) is ≤0.7mm, the elongation value listed in the table is reduced by 2.

7.6 Surface quality

7.6.1 The surface quality levels and characteristics of steel plates and steel strips are shown in Table 18.

Table 18 Surface quality levels and characteristics

Surface quality level code name characteristics

FA Ordinary grade surface allows the presence of small corrosion spots and unevenly sized zinc spatter. Dark spots, minor scratches and dents, air knife streaks, small dull spots, etc. There may be stretch straightening marks and zinc flow marks.

FB The higher-grade surface must not have corrosion spots, but slight surface imperfections are allowed, such as stretch straightening marks, smoothing indentations, scratches, embossing, zinc patterns, and zinc flow lines. , slight passivation defects, etc.

FC Premium Surface The superior side must not adversely affect the uniform appearance of a premium paint layer. The requirements for the other side should not be lower than surface level FB.

7.6.2 The surface quality of steel plates and steel strips based on hot-rolled pickled coils is only FA.

7.6.3 Unless otherwise agreed between the supplier and the buyer, only one side of the steel plates and steel strips with surface quality of FA grade or FB grade shall be inspected. Unless otherwise specified, the outer surface of the steel strip and the upper surface of the steel plate are the inspection surfaces.

7.6.4 Micro cracks in the zinc layer are allowed to exist on the edges of steel plates and steel strips that are not trimmed after plating.

7.6.5 The surface of steel plates and steel strips shall not have delamination, cracks or defects harmful to the next process. Since steel strips are difficult to detect and remove local surface defects during the continuous production process, delivery of strips with defects is allowed, but the defective parts shall not exceed 8% of the total length of each roll of steel strip.

8 Test method

8.1 The appearance of steel plates and steel strips shall be visually inspected.

8.2 The size and shape of steel plates and steel strips should be measured with appropriate measuring gauges and tools.

8.3 The inspection items, sampling quantity, sampling method and test method of each batch of steel shall be as specified in Table 19.

Table 19 Inspection items, sampling methods and test methods

Inspection items Sampling quantity Sampling method Test method description

Chemical analysis 1 (each furnace tank number) GB /T 222 GB/T 4336

Steel base tensile strength 1 GB/T 2795 GB/T 228 Test after removing zinc layer

Cold bending 1 GB/T 2795 GB/T 232 Remove For post-zinc layer testing, the width of the sample should not be less than 50mm

n, r value 1 GB/T 2795 GB/T 228 GB/T 5027

GB/T 5028 Remove the zinc layer Post-test

Zinc layer Zinc layer weight 1 — GB/T 1839 Each sample area 50c㎡

Bending 1 GB/T 2795 GB/T 232

8.4 The sampling location and quantity shall be as specified in Figure 1.

The unit is millimeters

50

1

3

2

500

Rolling direction

④

④

④

1—Steel base bending test specimen;

2—Coating bending test specimen;

3—Steel base tensile test specimen;

4—Zinc layer weight test specimen;

Figure 1 Sampling location map

9 Inspection rules

9.1 Steel plates and steel strips should be inspected in batches, each batch consisting of no more than 50 t of the same performance and the same steel base , composed of steel plates and steel strips with the same coating, the same surface structure, and the same surface treatment.

9.2 Re-inspection

9.2.1 Re-inspection of steel plates and steel strips shall comply with the provisions of GB/T 247 or GB/T 17505.

9.2.2 When products arrive at the user's factory and are reported to be defective, they should be stacked separately and protected so that the supplier can conduct appropriate investigations after being notified.

10 Packaging, marking and quality certificate

10.1 The packaging of steel plates and steel strips should comply with the requirements of GB/T 247.

10.2 In addition to the items specified in GB/T 247, the mark and quality certificate should also include performance level, steel base type, coating type, surface structure, surface treatment method, etc.

Is there a national standard number?

Appendix A

(Normative appendix)

Weight calculation method in theoretical weighing

A.1 When measuring the theoretical weight of steel plates, nominal dimensions are used.

A.2 The weight calculation method for theoretical weighting of steel plates shall be as specified in Table A.1 and Table A.2.

Table A.2

Zinc layer code 100 120 140 180 200 275 350 450

Equivalent calculated weight/(kg/㎡) 0.15 0.183 0.197 0.244 0.285 0.381 0.458 0.565

Equivalent zinc layer thickness/mm 0.02 0.026 0.028 0.034 0.04 0.054 0.064 0.08

Note: The zinc layer weight and equivalent zinc layer thickness of other zinc layer codes can be found in the table The column values ??are obtained by "interpolation method" or determined by negotiation between the supply and demand parties.

Table A.2

Number of digits in calculation sequence calculation method results

Basic weight of substrate/(kg/(mm*㎡)) 7.85 (thickness 1mm, weight of 1㎡ area) ——

Unit weight of substrate/(kg/㎡) Basic weight of substrate (kg/(mm*㎡)) X nominal thickness of substrate (mm) Rounded to valid Number 4 digits

Unit weight after galvanizing/(kg/㎡) Unit weight of substrate (kg/㎡) Calculated weight of zinc layer (kg/㎡) Rounded to 4 significant digits

Area of ??galvanized steel plate/㎡ Width (mm) kg* M-2) Units digit of kg

Total weight/kg Sum of weight of each bundle (kg) Integer of Kg

Note 1: The nominal thickness of the substrate is the ordering nominal thickness minus the ordering zinc layer code The corresponding equivalent zinc layer thickness.

Note 2: The total weight can also be calculated by the weight of 1 block (kg) x the total number of blocks