Q/BQB 310-2023 English PDF (QBQB310-2019, QBQB310-2018)

BASIC DATA
Standard ID	Q/BQB 310-2018 (Q/BQB310-2018)
Description (Translated English)	Hot-rolled steel sheets and strips for automotive structures
Sector / Industry	Chinese Industry Standard
Classification of Chinese Standard	QBQ
Word Count Estimation	8,867
Administrative Organization	Baoshan Iron and Steel Co., Ltd.

Q/BQB 310-2023 BQB ENTERPRISE STANDARD OF BAOSTEEL CO., LTD. Replacing Q/BQB 310-2019 Continuously hot-rolled steel sheet and strip for automobile structural use ISSUED ON: APRIL 09, 2023 IMPLEMENTED ON: JULY 01, 2023 Issued by: BaoSteel Co., Ltd. Table of Contents Foreword ... 3 1 Scope ... 4 2 Normative references ... 4 3 Terms and definitions ... 5 4 Classification and code ... 5 5 Information required for ordering ... 6 6 Dimensions, appearance, weight, allowable deviations ... 7 7 Technical requirements ... 7 8 Inspection and testing ... 12 9 Packaging, marking, inspection documents ... 14 10 Numerical rounding rules ... 14 11 Appendix ... 14 Appendix A (Informative) Comparison of similar designations between this document and relevant standards ... 15 Continuously hot-rolled steel sheet and strip for automobile structural use 1 Scope This document specifies the size, shape, technical requirements, inspection and testing, packaging, marking and inspection documents of continuously hot-rolled steel sheet and strip for automobile structural use. This document applies to carbon and micro-alloy steel continuously hot-rolled steel strips, which have good cold forming properties, as well as steel sheets cut crosswise and steel strips cut vertically, as produced by Baoshan Iron & Steel Co., Ltd., hereinafter referred to as steel sheets and strips. The products are used for manufacturing automobile beams, cross beams, wheels, automobile transmission shaft tubes, automobile axle housings and other structures. 2 Normative references The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) is applicable to this standard. GB/T 222-2006 Permissible tolerances for chemical composition of steel products GB/T 223 Chemical analysis methods for steel and alloys (applicable parts) GB/T 228.1-2021 Metallic materials - Tensile testing - Part 1: Method of test at room temperature GB/T 232 Metallic materials - Bend test 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 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 13298 Inspection methods of microstructure for metals GB/T 13299-1991 Steel - Determination of microstructure 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 Q/BQB 300 General rules of package mark and inspection document for continuously hot rolled steel sheet and strip Q/BQB 301 Hot-rolled steel sheets and strips - Dimensions, shape, weight and tolerances 3 Terms and definitions There are no terms or definitions to be defined in this document. 4 Classification and code 4.1 The designation, nominal thickness, uses of steel sheets and strips are as shown in Table 1. 4.2 According to the surface treatment methods, it is divided into: a) Pickled surface; b) Rolled surface. 4.3 According to the surface quality level, it is divided into: a) Ordinary grade surface, FA; b) Higher grade surface, FB. 4.4 According to the product category, it is divided into: a) Hot rolled steel strip; b) Hot rolled steel sheet; c) Hot rolled flat steel strip; d) Hot rolled slit steel strip; 5.2.1 If the surface treatment method is not specified, the product will be delivered with rolled surface. 5.2.2 For hot-rolled steel sheets and strips, if the dimensional precision is not specified, they will be delivered with ordinary precision, unless otherwise specified in this standard; if the edge state is not specified, the steel strips will be delivered without trimming and the steel sheets will be delivered with trimmed edges. 5.2.3 For hot-rolled pickled steel sheets and strips, if the dimensional precision is not specified, the thickness precision shall be delivered with higher thickness precision, whilst the other dimensions shall be delivered with ordinary precision; if the edge state, surface quality level and whether it is greased or not is not specified, it is delivered in trimmed state, higher-grade surface and greased; if the inner diameter of the steel coil is not specified, it will be delivered at an inner diameter of 610 mm. 6 Dimensions, appearance, weight, allowable deviations 6.1 The thickness tolerance of B440QZR and B480QZR shall comply with the requirements of Q/BQB 301 higher precision (PT.B). 6.2 Other dimensions, appearance, weight, allowable deviations are in accordance with the provisions of Q/BQB 301. 6.3 If the customer has higher requirements for thickness precision, the advanced precision PT.C given in Table 4 of Q/BQB 301 can be selected when ordering. 7 Technical requirements 7.1 Designation and chemical composition 7.1.1 The designation and chemical composition (smelting analysis) of steel shall comply with the requirements in Tables 2 ~ 3. The steel used for steel sheets and strips is killed steel, which is smelted in an oxygen converter. 7.3 Delivery state Steel sheets and strips are delivered in hot-rolled or controlled-rolled state. 7.4 Surface treatment methods 7.4.1 The surface treatment methods of steel sheets and strips can be rolling surface and pickling surface. 7.4.2 When steel sheets and strips have hot-rolled pickled surfaces, they are usually supplied with grease. The grease film shall be removable with alkali aqueous solution. Under normal packaging, transportation, loading and unloading, storage conditions, the supplier shall ensure that the surface of the steel sheet and strip will not rust within 3 months from the date of manufacturing completion. After negotiation between the supplier and the buyer, and indicating in the contract, the hot-rolled pickled surface can also be supplied without grease. Note: For non-greased products required by the purchaser, rust may occur; the surface may be slightly scratched during transportation, loading, unloading, storage, use. 7.5 Mechanical and process properties 7.5.1 The mechanical and process properties of steel sheets and strips shall comply with the requirements in the corresponding Tables 4 ~ 8. 7.5.2 After the bending test, there shall be no visible cracks on the outer surface of the specimen. If the supplier can ensure that the bending test is qualified, the test may be exempted. ......

Q/BQB 310-2019 ENTERPRISE STANDARD OF BAOSTEEL CO., LTD. Main technical indicators and test methods (Public Statement) Table of Contents 1 Chemical composition ... 3 2 Mechanical and process properties ... 4 3 Inspection and test ... 5 Main technical indicators and test methods (Public Statement) 1 Chemical composition Table 2 Table 3 Designation Chemical composition a (mass fraction) % a In order to improve the performance of the steel, other alloying elements can be added as required. At this time, the lower limit of Alt is not required. Designation Chemical composition a (mass fraction) % a One or more alloy elements of Nb, V, Ti can be added to steel, but Nb+V+Ti ≤0.22. ......

Q/BQB 310-2018 BQB ENTERPRISE STANDARD OF BAOSTEEL Hot-rolled steel sheets and strips for automotive structures Issued on. February 07, 2018 Issued by. Baoshan Iron and Steel Co., Ltd. Table of Contents Self-commitment ... 3 Technical indicator 1 ... 4 1 Dimensions, shape, weight and tolerance ... 5 2 Technical requirements ... 5 3 Inspection and testing ... 11 Self-commitment The contents of Q/BQB 310-2018 "Hot-rolled steel sheets and strips for automotive structures" prepared and published by our company are in compliance with relevant national laws and regulations, mandatory standards and relevant industrial policies. And it is approved by the corporate legal representative in accordance with the prescribed procedures. The products produced by our company meet the technical requirements stipulated in this Standard. The standard number is indicated on the corresponding product package. Our company is responsible for the truthfulness, accuracy and legality of the public information of the statement, and assumes full legal responsibility for the consequences of the implementation of this Standard. Baoshan Iron and Steel Co., Ltd. February 07, 2018 Technical indicator 1 Indicator name. Main technical indicators such as composition and performance Indicator requirements. The main technical indicators and test methods such as composition and performance are shown in the attachment. (See Page 4) Hot-rolled steel sheets and strips for automotive structures 1 Dimensions, shape, weight and tolerance 1.1 The thickness tolerance of B440QZR and B480QZR shall meet the requirements of Q/BQB 301 higher precision (PT.B). 1.2 Other dimensions, shapes, weights and tolerances are in accordance with Q/BQB 301. 1.3 If the purchaser needs higher requirements for thickness accuracy, the advanced precision PT.C given in Table 4 of Q/BQB 301 may be chosen when ordering. 2 Technical requirements ......