GB/T 20564.12-2019Continuously cold rolled high strength steel sheet and strip for automobile—Part 12:Dual phase steel with high formability (English PDF)

1 Scope

This Part of GB/T 20564 specifies the terms and definitions, classification and designation representation method, ordering contents, dimensions, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of continuously cold rolled high strength steel sheet and strip for automobile.

This Part applies to steel sheets and strips with a thickness of 0.50 mm ~ 3.00 mm, used for the manufacture of complex-forming automotive structural parts and reinforcements (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 223.9 Iron, steel and alloy - Determination of aluminium 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 223.12 Methods for chemical analysis of iron, steel and alloy - The sodium carbonate separation-diphenyl carbazide photometric method for the determination of chromium content

GB/T 223.17 Methods for chemical analysis of iron, steel and alloy - The diantipyryl methane photometric method for the determination of titanium content

GB/T 4336 Carbon and low-alloy steel - Determination of multi-element contents - Spark discharge atomic emission spectrometric method (routine method)

GB/T 5028 Metallic materials - Sheet and strip - Determination of tensile strain hardening exponent

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)

GB/T 24174 Steel - Determination of Bake-Hardening-Index (BH2)

3 Terms and definitions

For the purpose of this document, the following terms and definitions apply.

5 Ordering contents

b) reference to this Standard;

c) designation;

d) specifications and dimensions, flatness precision;

e) surface quality grade;

f) surface structure;

g) edge state;

h) packaging method;

i) weight;

j) use;

k) other special requirements.

5.2 If the dimensions and flatness precision, surface quality grade, surface structure type, edge state and packaging information are not indicated in the order contract, the supply party shall supply according to ordinary dimensions and flatness precision, higher grade surface, pitted surface structure, edge-trimmed state, and package according to the packaging method provided by the supply party.

6 Dimensions, shape, weight

The dimensions, shape, weight and tolerance of steel sheets and strips shall comply with the provisions of GB/T 708.

7 Technical requirements