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GB/T 20564 consists of seven 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: Interstitial free steel;
——Part 4: High strength low alloy steel;
——Part 5: Isotropic steel;
——Part 6: Transformation induced plasticity steel;
——Part 7: Martensitic steels;
This part is Part 7 of GB/T 20564.
Annex A and Annex B of this part are informative.
This part was proposed by China Iron and Steel Association.
This part is under the jurisdiction of National Technical Committee on Iron and Steel of Standardization Administration of China.
Continuously cold rolled high strength steel sheet and strip for automobile —
Part 7: Martensitic steels
1 Scope
This part specifies the term and definition, classification and code, dimension, shape, weight, technical requirements, inspections and tests, packaging, marks and quality certificates of cold rolled martensitic high strength steel sheets and strips (hereinafter referred to as “steel sheets and strips”).
This part is applicable to steel sheets and steel strips with a thickness of 0.50mm~2.1mm, which are mainly used for manufacturing structural members and reinforcing members of automobiles.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply to this part.
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 223.23 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 223.53 Methods for chemical analysis of iron, steel and alloy; The flame atomic absorption spectrophotometric method for the determination of copper 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 223.67 Iron steel and alloy — Determination of sulfur content — Methylene blue spectrophotometric method
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 223.69 Iron, steel and alloy — Determination of carbon contents — Gas-volumetric method after combustion in the pipe furnace
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 223.72 Iron steel and alloy — Determination of sulfur content — Gravimetric method
GB/T 228 Metallic materials — Tensile testing at ambient temperature
GB/T 247 General rule of package, mark and certification for steel plates(sheets) and strips
GB/T 7080 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 Standard test method for spark discharge atomic emission spectrometric analysis of carbon and low — Alloy steel (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 part, the following term and definition apply.
3.1
martensitic steels; MS
steel whose microstructure is almost entirely martensitic, which has high strength and certain formability
4 Classification and code
4.1 The designation of steel sheet and strip consists of three parts: the initials “CR” of “Cold Rolled”, the specified minimum yield strength value/specified minimum tensile strength value, and the initials “MS” of “Martensitic Steels”.
Example: CR1200/1500MS
CR—initials of “Cold Rolled”;
1200/1500—1200: the specified minimum value of lower yield strength, 1500: the specified minimum tensile strength, MPa;
MS—initials of English “Martensitic Steels”.
4.2 The steel plates and strips are classified according to their purposes and characteristics as specified in Table 1.
Table 1
Designation Purpose
CR500/780MS Structural member, reinforcing member
CR700/900MS
CR700/980MS
CR860/1100MS
CR950/1180MS
CR1030/1300MS
CR1150/1400MS
CR1200/1500MS
4.3 The surface quality of steel sheets and strips shall meet the requirements specified in Table 2.
Foreword i
1 Scope
2 Normative references
3 Term and definition
4 Classification and code
5 Ordering Information
6 Dimension, shape, weight and tolerance
7 Technical requirements
8 Inspections and tests
9 Packaging, marking and quality certificate
10 Rounding off for numerical values
11 Comparison of similar designations between domestic and foreign standards
Annex A (Informative) Reference values of chemical composition
Annex B (Informative) Comparison of similar designations between domestic and foreign standards
