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GB/T 20564 consists of the following eleven parts under the general title Continuously cold rolled high strength steel sheet and strip for automobile:
——Part 1: Bake hardening steel;
——Part 2: Dual phase steel;
——Part 3: High strength interstitial free steel;
——Part 4: High strength low alloy steel;
——Part 5: Isotropic steel;
——Part 6: Transformation induced plasticity steel;
——Part 7: Martensitic steels;
——Part 8: Complex phase steel;
——Part 9: Quenching and partitioning steel;
——Part 10: Twinning induced plasticity steel;
——Part 11: Carbon manganese steel.
This part is Part 10 of GB/T 20564.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part was proposed by China Iron and Steel Association.
This standard is under the jurisdiction of the SAC/TC 183 National Technical Committee on Iron and Steel of Standardization Administration of China.
Continuously cold rolled high strength steel sheet and strip for automobile — Part 10: Twinning induced plasticity steel
1 Scope
This part of GB/T 20564 specifies the term and definition, classification and designation representation methods, order information, dimension, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificate for cold rolled twinning induced plasticity high strength steel sheets and strips.
This part is applicable to the 0.50 mm to 3.00 mm-thick steel sheets and strips for manufacturing automobile complex-shape structural member and reinforcing member with a thickness of 0.50 mm~3.00 mm (hereinafter referred to as "steel sheets and strips").
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 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 223.59 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 223.68 Methods for chemical analysis of iron, steel and alloy—The potassium iodate titration method after combustion in the pipe furnace for the determination of sulfur content
GB/T 223.71 Methods for chemical analysis of iron, steel and alloy — The gravimetric method after combustion in the pipe furnace for the determination of carbon content
GB/T 223.79 Iron and steel — Determination of multi-element contents — X-ray fluorescence spectrometry (Routine method)
GB/T 228.1-2010 Metallic materials — Tensile testing — Part 1: Method of test at room temperature
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 2523 Measuring method of surface roughness and peak count for cold-rolled metal sheet (strip)
GB/T 2975 Steel and steel products — Location and preparation of samples and test pieces for mechanical testing
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 judgement 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)
3 Term and definition
For the purposes of this standard, the following term and definition apply.
3.1
twinning induced plasticity steel; TWIP
steel whose good plasticity is obtained by adding stable austenite through high alloy to room temperature and single-phase austenite delaying the necking surface through twin formation in the plastic deformation process, and improved by austenite strain-inducing martensite transformation in the high strain zone, which also delays the necking
Note: TWIP steel possesses extremely high strength-plasticity product, which may be used to form complex-shape structural members or reinforcing member.
4 Classification and designation representation method
4.1 Classification
4.1.1 See Table 1 for the classification of steel sheets and strips by surface quality.
Table 1 Classification of steel sheets and strips by quality surface
Grade Code
Relatively high grade surface FB
Higher grade surface FC
4.1.2 See Table 2 for the classification of steel sheets and strips by surface structure.
Table 2 Classification of steel sheets and strips by surface structure
Surface structure Code
Pitted surface D
Smooth surface B
4.2 Designation representation method
The designation of steel sheet and steel strip is composed of the initials "CR" of "Cold Rolled", the specified minimum yield strength value/specified minimum tensile strength value, and the characteristic letter of "TW" of “TWinning induced plasticity”.
Example: CR400/950TW
CR——the initials of "Cold Rolled";
400/950——the specified minimum yield strength value/specified minimum tensile strength value, MPa;
TW——the characteristic letter of "TWining induced plasticity".
5 Order information
5.1 Contracts or orders made based on this part shall cover the following items:
a) product name (steel sheet or strip);
b) number of this part;
c) designation;
d) specification, dimension and roughness accuracy;
e) surface quality grade;
f) surface structure;
g) edge state;
h) packaging method;
i) weight;
j) application;
k) other special requirements.
5.2 If information such as dimension and roughness precision, surface quality grade, surface structure type, edge condition and packaging, is not specified in the order contract, the supplier shall supply this part of products in common size and common roughness precision, relatively high grade and pitted surface structure, and shall pack the products in the manner given by the supplier.
6 Dimension, shape and weight
The dimension, shape, weight and tolerance of steel sheets and strips shall meet those specified in GB/T 708.
7 Technical requirements
7.1 Chemical composition
See Annex A for reference values of chemical composition of steels (smelting analysis). If the purchaser has any special requirements for chemical composition, it shall be negotiated when ordering.
7.2 Smelting method
The steels for steel sheets and strips are smelted by oxygen converter or electric furnace; unless otherwise specified, the smelting method shall be chosen by the supplier.
Foreword i
1 Scope
2 Normative references
3 Term and definition
4 Classification and designation representation method
5 Order information
6 Dimension, shape and weight
7 Technical requirements
8 Test methods
9 Inspection rules
10 Packaging, marking and quality certificate
Annex A (Informative) Chemical composition of steel
