GB/T 20887.6-2017 PDF in English
GB/T 20887.6-2017 (GB/T20887.6-2017, GBT 20887.6-2017, GBT20887.6-2017)
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| GB/T 20887.6-2017 | English | 145 |
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Continuously hot rolled high strength steel sheet and strip for automobile -- Part 6: Complex phase steel
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Standards related to (historical): GB/T 20887.6-2017
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GB/T 20887.6-2017: PDF in English (GBT 20887.6-2017) GB/T 20887.6-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.50
H 46
Continuously hot rolled high strength steel sheet and
strip for automobile - Part 6. Complex phase steel
ISSUED ON. SEPTEMBER 7, 2017
IMPLEMENTED ON. JUNE 1, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 6
4 Classification and designation representing method ... 6
5 Ordering content ... 7
6 Dimensions, shape, weight ... 8
7 Technical requirements ... 8
8 Test methods ... 10
9 Inspection rules ... 11
10 Package, mark, and quality certificate ... 11
Appendix A (Informative) Reference values for chemical composition ... 12
Appendix B (Informative) Approximate comparison between designations in
domestic and in foreign standards ... 13
Continuously hot rolled high strength steel sheet and
strip for automobile - Part 6. Complex phase steel
1 Scope
This Part of GB/T 20887 specifies the classification and designation
representing method, ordering content, dimensions, shape, weight, technical
requirements, test methods, inspection rules, package, mark, and quality
certificate of hot rolled high strength complex phase steel sheet and strip.
This Part applies to the steel strip with a thickness of no more than 8 mm and
steel plate cut transversely from steel strip and longitudinally-cut steel strip
(hereafter known as “steel plate and strip” for short) for the production of
automobile structural parts and reinforcements.
2 Normative references
The following documents are indispensable for the application of this document.
For the dated references, only the versions with the dates indicated are
applicable to this document. For the undated references, the latest version
(including all the amendments) are applicable to this document.
GB/T 222 Permissible Tolerances for Chemical Composition of Steel
Products
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 223.17 Methods for Chemical Analysis of Iron Steel and Alloy - The
Diantipyrylmethane Photometric Method for the Determination of Titanium
Content
GB/T 223.26 Iron, Steel and Alloy - Determination of Molybdenum Content -
The Thiocyanate Spectrophotometric Method
GB/T 223.40 Iron, Steel and Alloy - Determination of Niobium Content by the
Sulphochlorophenol S Spectrophotometric Method
GB/T 223.58 Methods for chemical analysis of iron, steel and alloy - The
sodium arsenite-sodium nitrite titrimetric method for the determination of
manganese 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 223.68 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 223.75 Iron, steel and alloy - Determination of boron content - Methanol
distillation-curcumin photometric method
GB/T 223.76 Methods for chemical analysis iron, steel and alloy - The flame
atomic absorption spectrometric method for the determination of vanadium
content
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 709 Dimensions, Shape, Weight and Tolerances for Hot Rolled Steel
Sheets and Strips
GB/T 2975 Steel and Steel Products - Location and Preparation of 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 6394 Metal - Methods for estimating the average grain size
GB/T 8170 Rules of rounding off for numerical values & expression and
judgement of limiting values
GB/T 10561 Steel - Determination of Content of Nonmetallic Inclusions -
Micrographic Method Using Standards Diagrams
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 24524 Metallic materials - Sheet and strip - Hole expanding test
3 Terms and definitions
The following terms and definitions are applicable to this document.
3.1 Complex phase steel; CP
The microstructure of the steel is a small amount of martensite, retained
austenite, or pearlite distributed on the ferrite or bainite matrix. Fine-grain
strengthening or precipitation strengthening by microalloying elements.
Compared with dual phase steels with the same tensile strength, it has higher
yield strength and certain flanging hole expanding property.
4 Classification and designation representing method
4.1 Classification
4.1.1 The steel sheet and strip can be classified into hot-rolled surface and hot-
rolled pickling surface as per the surface states. When the surface state is hot-
rolled pickling surface, it shall be denoted by Code “P”.
products shall be supplied as per hot rolled surface, ordinary thickness
accuracy, ordinary surface (FA), edge-cutting state, and oil-coated. For hot-
rolled pickling surface, if the surface quality level and oil use are not specified,
the products shall be supplied as per relative-high surface (FA) [should be. FB]
and oil-coated.
6 Dimensions, shape, weight
The dimensions, shape, weight, and permissible tolerances of steel sheet and
strip shall comply with the provisions of GB/T 709.
7 Technical requirements
7.1 Chemical composition
7.1.1 Reference values for chemical composition (melting analysis) of steel are
given in Appendix A. If the demand side has a requirement for chemical
composition, it shall be negotiated when ordering. Approximate comparison
between designations in domestic and foreign standards is shown in Appendix
B.
7.1.2 The permissible tolerances for chemical composition of steel products
shall comply with the provisions of GB/T 222.
7.2 Smelting method
The steel used for steel sheet and strip is smelted using an oxygen converter
or an electric furnace. Unless otherwise specified, the smelting method shall be
selected by the supplier.
7.3 Delivery state
7.3.1 Steel sheet and strip are usually delivered in hot rolled state.
7.3.2 When the steel plate and strip have a hot-rolled pickling surface, they are
usually supplied oiled. The oil film coated shall be able to be removed with
aqueous alkali. Under normal package, transport, loading-unloading, and
storage conditions, the supplier shall ensure that, within 3 months from the date
of completion of manufacture, the surface of steel sheet and strip does not rust.
If negotiated by both sides of the supply and demand and indicated in the
contract, hot-rolled pickling surface may be supplied without oil-coated.
Note. For non-oiled products required by the demand side, there may be corrosion; and
during transport, loading-uploading, storage, and use, the surface may be slightly
6 Dimensions, shape
Piece by
piece/roll by roll -
Suitable measuring
tool
7 Surface quality Piece by piece/roll by roll - Visual
9 Inspection rules
9.1 The inspection and acceptance of steel sheet and strip shall be performed
by the supplier’s inspection department.
9.2 The steel sheet and strip shall be accepted in batches. Each batch shall
consist of steel sheets and strips of the same designation, the same furnace
number, the same thickness, and the same rolling mechanism with a weight of
no more than 60 t. For the steel strip and continuously rolled sheet with roll
weight greater than 30 t, each two rolls shall be regarded as one batch.
9.3 The sampling quantity and sampling methods for steel sheet and strip shall
conform to the provisions of Table 3.
9.4 The re-inspection and judgement rules of steel sheet and strip shall conform
to the provisions of GB/T 17505.
9.5 The test results of chemical composition and mechanical properties shall
be rounded off according to the rounding off value comparison method. The
rounding off rules shall be in accordance with the provisions of GB/T 8170.
10 Package, mark, and quality certificate
The package, mark, and quality certificate of steel sheet and strip shall conform
to the provisions of GB/T 247. If the demand side has a special requirement for
the package, it can be negotiated when ordering.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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