Standard No.:	GB/T 20564.14-2023
English Name:	Continuously cold rolled high strength steel sheet and strip for automobile―Part 14:Low density steel
Chinese Name:	汽车用高强度冷连轧钢板及钢带 第14部分：低密度钢
Chinese Classification:	H46    Steel sheet and strip
Professional Classification:	GB    National Standard
ICS Classification:	77.140.50 77.140.50    Flat steel products and semi-products 77.140.50
Issued by:	SAMR; SAC
Issued on:	2023-08-06
Implemented on:	2024-3-1
Status:	valid
Language:	English
File Format:	PDF
Word Count:	5500 words
Price(USD):	165.0
Delivery:	via email in 1~3 business day

Foreword This document is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents. This document is Part 14 of GB/T 20564 under the general title of Continuously cold rolled high strength steel sheet and strip for automobile. The following parts of GB/T 20564 have been issued: ——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 steel; ——Part 8: Complex phase steel; ——Part 9: Quenching and partitioning steel; ——Part 10:Twinning induced plasticity steel; ——Part 11: Carbon manganese steel; ——Part 12:Dual phase steel with high formability; ——Part 13: Medium manganese steel; ——Part 14: Low density steel. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights. This document was proposed by China Iron and Steel Association. This document is under the jurisdiction of the National Technical Committee on Iron and Steel of Standardization Administration of China (SAC/TC 183). 本文件起草单位:鞍钢股份有限公司、冶金工业信息标准研究院、湖南华菱涟源钢铁有限公司、首钢集团有限公司、中国第-汽车股份有限公司。 本文件主要起草人:郭金宇、苏皓璐、李倩、李江、姜英花、曹广祥、刘仁东、田子健、田飞、唐牧、赵隆卿、孟静竹、孙梦寒、张维旭。   Introduction GB/T 20564 is developed to standardize the continuously cold rolled high strength steel sheet and strip for automobile in terms of designation expression and classification, order information, dimension, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificate. GB/T 20564 consists of 14 parts. ——Part 1. Bake hardening steel. It is intended to determine the technical requirements for continuously cold rolled bake hardening high strength steel sheet and strip with thickness of 0.50 mm to 3.00 mm, which are mainly used for making outer plates, inner plates and some structural parts of automobile. ——Part 2. Dual phase steel. It is intended to determine the technical requirements for continuously cold rolled dual phase high strength steel sheet and strip with thickness of 0.50 mm to 3.00 mm, which are mainly used for making structural parts, stiffeners and some inner and outer plates of automobile. ——Part 3. High strength interstitial free steel. It is intended to determine the technical requirements for continuously cold high strength interstitial free steel sheet and strip with thickness of 0.50 mm to 3.00 mm, which are mainly used for making outer plates, inner plates and some structural parts of automobile. ——Part 4. High strength low alloy steel. It is intended to determine the technical requirements for continuously cold rolled high strength low alloy steel sheet and strip with thickness of 3.0 mm or less, which are mainly used for making structural parts and stiffeners of automobile. ——Part 5: Isotropic steel. It is intended to determine the technical requirements for continuously cold rolled isotropic high strength steel sheet and strip with thickness of 2.5 mm or less, which are mainly used for making outer coverage of automobile. ——Part 6: Transformation induced plasticity steel. It is intended to determine the technical requirements for continuously cold rolled transformation induced plasticity high strength steel sheet and strip with thickness of 0.50 mm to 2.5 mm, which are mainly used for making structural parts and stiffeners of automobile. ——Part 7: Martensitic steel. It is intended to determine the technical requirements for continuously cold rolled martensitic high strength steel sheet and strip with thickness of 0.50 mm to 2.1 mm, which are mainly used for making structural parts, stiffeners and anti-collision parts of automobile. ——Part 8: Complex phase steel. It is intended to determine the technical requirements for continuously cold rolled complex phase high strength steel sheet and strip with thickness of 0.60 mm to 2.50 mm, which are mainly used for making structural parts, stiffeners and some inner and outer parts of automobile. ——Part 9. Quenching and partitioning steel. It is intended to determine the technical requirements for continuously cold rolled quenching and partitioning high strength steel sheet and strip with thickness of 0.8 mm to 2.5 mm, which are mainly used for making structural parts and stiffeners of automobile. ——Part 10. Twinning induced plasticity steel. It is intended to determine the technical requirements for continuously cold rolled twinning induced plasticity high strength steel sheet and strip with thickness of 0.50 mm to 3.00 mm, which are mainly used for making structural parts with complicated shape and stiffeners of automobile. ——Part 11: Carbon manganese steel. It is intended to determine the technical requirements for continuously cold rolled carbon manganese high strength steel sheet and strip with thickness of 0.50 mm to 3.00 mm, which are mainly used for making structural parts of automobile. ——Part 12. Dual phase steel with high formability. It is intended to determine the technical requirements for continuously cold rolled high strength steel sheet and strip - dual phase steel with high formability with thickness of 0.50 mm to 3.00 mm, which are mainly used for making structural parts with complicated shape and stiffeners of automobile. ——Part 13. Medium manganese steel. It is intended to determine the technical requirements for continuously cold rolled medium manganese high strength steel sheet and strip with thickness of 1.0 mm to 2.5 mm, which are mainly used for making structural parts and stiffeners of automobile. ——Part 14: Low density steel. It is intended to determine the technical requirements for continuously cold rolled low density high strength steel sheet and strip with thickness of 0.6 mm to 3.0 mm, which are mainly used for making structural parts and stiffeners of automobile. Continuously cold rolled high strength steel sheet and strip for automobile - Part 14: Low density steel 1 Scope This document specifies the designation expression, classification, order information, dimension, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of continuously cold rolled low density steel high strength steel sheet and strip for automobile. This document is applicable to continuously cold rolled low density steel high strength steel sheet and strip with thickness of 0.6 mm to 3.0 mm, which are mainly used for making automobile structural parts and stiffeners (hereinafter referred to as "sheet and strip"). 2 Normative references The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies. GB/T223.4 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 aluminium content - Chrome azurol S photometric method GB/T 223.40 Iron, steel and alloy - Determination of niobium content by the sulphochlorophenol S spectrophotometric method GB/T223.59 Iron, steel and alloy—Determination of phosphorus content - Bismuth phosphomolybdate blue spectrophotometric method and antimony phosphomolybdate blue spectrophotometric method GB/T 223.76 Methods for chemical analysis of iron, steel and alloy - The flame atomic absorption spectrometric method for the determination of vanadium content GB/T 223.84 Steel and alloy - Determination of titanium content - Diantipyrylmethane spectrophotometric method GB/T223.85 Steel and iron - Determination of sulfur content - Infrared absorption method after combustion in an induction furnace GB/T223.86 Steel and iron - Determination of total carbon content - Infrared absorption method after combustion in an induction furnace GB/T 228.1-2021 Metallic materials - Tensile testing - Part 1: Method of test at room temperature GB/T247 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, peak count and waviness for cold-rolled metal sheet and strip GB/T 2975 Steel and steel products - Location and preparation of test pieces for mechanical testing 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 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 Low density steel a high-strength steel with good mechanical properties by adding different contents of Al, Mn, Si and other lightweight elements and density reduction of no less than 4% 4 Designation expression and classification 4.1 Designation expression The designation of steel sheet and strip consists of three parts: the initial capital letters of “ColdRolled", i.e., “CR”; the specified minimum yield strength / specified minimum tensile strength; and the initial capital letters of "LowDensity”, i.e., “L.D". For example: CR400/980L.D, in which: CR: the initial capitals of “ColdRolled”; 400/980: the specified minimum yield strength is 400; the specified minimum tensile strength is 980, expressed in MPa; LD: the initial capital letters of "LowDensity".

Foreword i Introduction iii 1 Scope 2 Normative references 3 Terms and definitions 4 Designation expression and classification