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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 2520-2008 Cold-reduced electrolytic tinplate The following main technical changes have been made with respect to GB/T 2520-2008:
——The thickness of single cold-reduced products in the applicable scope is modified to 0.14 mm~0.80 mm (see Chapter 1, Chapter 1 of 2008 edition);
——The classification method is modified, the passivation method is modified to the surface treatment method, and the “no treatment" is added (see Table 1, 2008 edition);
——The definition of "chemical treated electrolytic tinplate" is deleted (see 3.7 of 2008 edition);
——The immersion solution of chemical passivation and electrochemical passivation is modified (see 3.7 and 3.8 herein; 3.8 and 3.9 of 2008 edition);
——The content of "The nominal thickness may be upgraded by other thickness multiples after negotiation between the supplier and the purchaser" is added (see 6.1.1);
——The steel grade of black plate and chemical composition of the cold-reduced tinplate is added; and the criteria for chemical composition testing methods in the normative reference documents is added (see Clause 2 and Table 2).
——The requirements for the limitation of toxic and harmful elements in the black plate and tin coating of the tinplate used for producing containers in direct contact with food, medicine and beverage (with or without organic coating on the surface) is added (see 7.1.3 and 7.3.5);
——The requirement of the minimum average tin coating mass when ordering with tin coating mass other than the specified mass is added (see 7.3.1);
——The requirement of "the rounding interval of a single point test value on each side is 0.05g/m2" is added (see 7.3.3);
——The surface state S of double cold-reduced products is added (see table 8);
——The requirement that the diamond anvil shall be used for hardness measurement equipment is added (see 8.5);
——Appendix B "Rebound test method" is modified (see Appendix B, Appendix B of 2008 edition);
——Appendix E "Precautions for application of tinplate” is added;
——Appendix F "Determination of plumbum content in tinplate coating” is added.
This standard was proposed by China Iron and Steel Association.
This standard is under the jurisdiction of the Technical Committee on Steel of Standardization Committee of China (SAC/TC 183).
The previous editions replaced by this standard are as follows:
——GB/T 2520-1981, GB/T 2520-1988, GB/T 2520-2000, GB/T 2520-2008.
Cold-reduced electrolytic tinplate
1 Scope
This standard specifies the classification and code, ordering content, dimension, shape, weight, tolerance, technical requirements, test methods, inspection rules, packaging, marking and product quality certificates for cold-reduced electrolytic tinplate.
This standard is applicable to single cold-reduced electrolytic tinplate with a nominal thickness of 0.14mm~0.80mm and double cold-reduced electrolytic tinplate with a nominal thickness of 0.12mm~0.36mm (hereinafter collectively referred to as “tinplate”).
2 Normative references
The following referenced documents are indispensable for the application of this document for dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 222 Permissible tolerances for chemical composition of steel products
GB/T 223.4 Alloyed steel — Determination of manganese content — Potentiometric or visual titration method
GB/T 223.5 Steel and iron — Determination of acid-soluble silicon and total silicon content — Reduced molybdosilicate spectrophotometric method
GB/T 223.9 Iron, steel and alloy — Determination of aluminum content — Chrome azurol S photometric method
GB/T 223.11 Iron steel and alloy — Determination of chromium content — Visual titration or potentiometric titration method
GB/T 223.18 Methods for chemical analysis of iron, steel and alloy — The sodium (potassium) periodate photometric method for the determination of manganese content
GB/T 223.23 Iron, steel and alloy — Determination of nickel content — The dimethylglyoxime spectrophotometric method
GB/T 223.26 Iron, steel and alloy — Determination of molybdenum content — The thiocyanate spectrophotometric method
GB/T 223.29 Iron, steel and alloy — Determination of plumbum content — Carrier precipitation-xylenol orange spectrophotometric method
GB/T 223.31 Iron, steel and alloy — Determination of arsenic content —Distillation-molybdenum blue spectrophotometric method
GB/T 223.57 Methods for chemical analysis of iron, steel and alloy — The extraction-absorption catalytic polarographic method for the determination of cadmium content
GB/T 223.59 Iron, steel and alloy — Determination of phosphorus content — Bismuth phosphomolybdate blue spectrophotometric method and antimony phosphomolybdate blue spectrophotometric method
GB/T 223.60 Methods for chemical analysis of iron, steel and alloy — The perchloric acid dehydration gravimetric method for the determination of silicon content
GB/T 223.63 Methods for chemical analysis of iron, steel and alloy — The sodium (potassium) periodate photometric method for the determination of manganese content
GB/T 223.64 Iron steel and alloyed — Determination of manganese content — Flame atomic absorption spectrometric method
GB/T 228.1-2010 Metallic materials — Tensile testing — Part 1: Method of test at room temperature
GB/T 230.1 Metallic Rockwell hardness test - Part 1: Test method (Scales A, B, C, D, E, F, G, H, K, N, T)
GB/T 247 General rule of package, mark and certification for steel plates (sheets) and strips
GB/T 708 Dimension, shape, weight and tolerance for cold-rolled steel strip and sheet
GB/T 728-2010 Ingot tin
GB/T 1838 Test methods of tin coating mass for electrolytic tinplate
GB/T 4336 Carbon and low-alloy steel — Determination of multi-element contents — Spark discharge atomic emission spectrometric method (routine method)
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 17505 Steel and steel products — General technical delivery requirements
GB/T 20066 Steel and iron — Sampling and preparation of samples for the determination of chemical composition
GB/T 20123 Steel and iron — Determination of total carbon and sulfur content — Infrared absorption method after combustion in an induction furnace (routine method)
GB/T 20125 Low-alloy steel — Determination of multi-element contents — Inductively coupled plasma atomic emission spectrometric method
GB/T 20126 Unalloyed steel — Determination of low carbon content — Part 2: Infrared absorption method after combustion in an induction furnace (with preheating)
GB/T 22316 Test methods of corrosion resistance for electrolytic tinplate
GB/T 28290 Methods for determination of surface chromium on electrolytic tinplate
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
electrolytic tinplate
cold-reduced low-carbon tinplate with tin coating on both sides obtained by continuously electrolytic tin operation
3.2
differentially coated electrolytic tinplate
electrolytic tinplate with different tin coating on both sides
3.3
single cold-reduced; SR
process in which steel substrate is cold reduced to required thickness, and then annealed and flattened
3.4
double cold-reduced; DR
process in which steel substrate is cold reduced for the second time with a larger reduction, after being cold reduced for the first time and annealed
3.5
box annealing; BA
annealing process of cold-reduced steel strip according to the set time and temperature period in a tightly rolled state under the controlled atmosphere
3.6
continuous annealing; CA
annealing process of cold-reduced steel strip according to the set time and temperature period in an unrolled state under the controlled atmosphere
3.7
chemical passivation
loss of chemical reactivity experienced by tin-plated steel strip immersed in a chemical solution
3.8
electrochemical passivation
cathodic chemical passivation under electrification carried out for tin-plated steel strip immersed in a chemical solution.
3.9
low chromate passivation
chemical passivation treatment, in which the target value of chromium content in the surface passivation film shall be controlled below 1.5mg/m2
3.10
K plate
tinplate with good corrosion resistance whose tin coating shall not be less than 5.6/2.8g/m2, and whose target value shall meet the following requirements after four special tests of measuring pickling time lag value (PLV), iron solution value (ISV), tin crystal size (TCS) and alloy-tin electrical coupling (ATC) are carried out:
a) PLV≤10s;
b) TCS ≤Grade 9;
c) ISV≤20μg;
d) ATC≤0.12μA/cm2
3.11
J plate
tinplate with good corrosion resistance whose tin coating mass shall not be less than 5.6/2.8g/m2, and whose target value shall meet the relevant requirements of 3.10 after four special tests of measuring pickling time lag value (PLV), iron solution value (ISV), tin crystal size (TCS) and alloy-tin electrical coupling (ATC) are carried out
4 Classification and code
Classification and code of tinplate shall meet those specified in Table 1.
Table 1
Classification Class Code
Steel grade of black plate — MR, L, D
Temper Single cold-reduced tinplate T-1, T-1.5, T-2, T-2.5, T-3, T-3.5, T-4, T-5
Double cold-reduced tinplate DR-7M, DR-8, DR-8M, DR-9, DR-9M, DR-10
Annealing Continuous annealing CA
Box annealing BA
Differentially coated tin plating marking Marking method of thin surface D
Marking method of thick surface A
Surface state Bright B
Rough R
Silver S
Matting M
Surface treatment method Passivation Chemical passivation CP
Electrochemical passivation CE
Low chromium LCr
No treatment U
Edge shape Straight edge SL
Lace WL
4.2 Designation representation method
4.2.1 For general tinplate, their designation generally consists of steel grade of black plate, temper code and annealing mode code.
Example: MR T-2.5 CA, L T-3 BA and MR DR-8 BA
4.2.2 For tinplate used to produce 2-piece drawing (DI), steel grade of black plate is only applicable to Grade D. Its designation consists of Grade D code, temper code, annealing mode code and code DI.
Example: D T-2.5 CA DI
4.2.3 For tinplate used to produce food cans with plain surface (tin coating mass: 5.6/2.8g/m2) holding acidic content, namely K plate, steel grade of black plate is generally Grade L. Its designation generally consists of Grade L code, temper code, annealing mode code and code K.
Example: L T-2.5 CA K
4.2.4 For tinplate used to produce food cans holding objects that require low chromate treatment such as mushroom, steel grade of black plate is generally Grade MR or Grade L. Their designation consist of Grade MR or L, temper code, annealing mode code and code LCr.
Example: MR T-2.5 CA LCr
5 Order information
Contracts and orders based on this standard shall cover the following items:
a) product name (tinplate);
a) standard No. of this product;
c) designation;
d) dimensions (width, length or inside diameter);
e) code of tin coating mass;
f) surface treatment method;
g) marking method of differentially coated tin plating;
h) edge shape;
i) packaging method;
j) application;
k) quantity or weight;
l) others.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Classification and code
5 Order information
6 Dimension, shape, weight and tolerance
7 Technical requirements
8 Test methods
9 Inspection rules
10 Package, marking and quality certificate
11 Approximate comparison for temper codes in relevant standards at home and abroad
12 Precautions for the application of tinplate
Appendix A (Normative) Marking method for thick surface of differentially coated tinplate
Appendix B (Informative) Rebound test method
Appendix C (Normative) Conversion of HR15T and HR30Tm
Appendix D (Informative) Comparison between the temper codes in this standard and those (or steel grade codes) in relevant standard
Appendix E (Informative) Precautions for application of tinplate
Appendix F (Normative) Determination of plumbum content in tinplate coating
