Q/BQB 306-2023 PDF in English
Q/BQB 306-2023 (Q/BQB306-2023, QBQB 306-2023, QBQB306-2023)
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| Q/BQB 306-2023 | English | 290 |
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Continuously hot-rolled steel sheet and strip for automobile frame
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Standards related to (historical): Q/BQB 306-2023
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Q/BQB 306-2023: PDF in English (QBQB 306-2023) Q/BQB 306-2023
BQB
BAOSHAN IRON & STEEL CO., LTD.
ENTERPRISE STANDARD
Replacing Q/BQB 306-2019
Continuously hot-rolled steel sheet and strip for automobile
frame
ISSUED ON. APRIL 09, 2023
IMPLEMENTED ON. JULY 01, 2023
Issued by. Baoshan Iron & Steel 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, shape, weight, allowable deviations... 7
7 Technical requirements... 7
8 Inspection and test... 11
9 Packaging, marking, inspection documents... 13
10 Rules for rounding off values... 13
11 Appendix... 13
Appendix A (Informative) Comparison of similar designations between this document
and relevant standards... 14
Continuously hot-rolled steel sheet and strip for automobile
frame
1 Scope
This document specifies the dimensions, appearance, technical requirements,
inspection and test, packaging, marking and inspection documents of hot-rolled steel
sheets and strips for automobile frames.
This document is applicable to hot-rolled steel strips for automobile frames produced
by Baoshan Iron & Steel Co., Ltd., as well as the steel sheets cut laterally and the
longitudinally steel strips cut longitudinally, hereinafter referred to as steel sheets and
strips.
2 Normative references
The contents of the following documents constitute essential clauses of this document
through normative references in the text. For references with dates, only the versions
corresponding to the dates apply to this document; for references without dates, the
latest versions (including all amendments) apply to this document.
GB/T 222-2006 Permissible tolerances for chemical composition of steel products
GB/T 223 Methods for chemical analysis of iron, steel and alloy (applicable parts)
GB/T 228.1-2021 Metallic materials - Tensile testing - Part 1.Method of test at room
temperature
GB/T 229 Metallic materials - Charpy pendulum impact test method
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 Determination of estimating the average grain size of metal
GB/T 8170 Rules of rounding off for numerical values and 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 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
Q/BQB 300 General rules of package, mark and inspection document for
continuously hot rolled steel sheet and strip
Q/BQB 301 Dimension, shape, weight and tolerances for continuously hot-rolled
steel sheet and strip
3 Terms and definitions
There are no terms and definitions that need to be defined in this document.
4 Classification and code
4.1 Designation indication method
The steel designation consists of the first letter "B" of the pinyin of "Bao" in Baosteel
Co., Ltd., the value of the specified minimum tensile strength (unit. MPa), the first letter
"L" of the pinyin of "Liang" representing the purpose of the frame. When used for semi-
trailer frames, add the initials "ST" of the English word for semi-trailer before the value
of the specified minimum tensile strength.
Example 1.B510L
B - The initials of "Bao" in Baosteel Co., Ltd.;
510 - The specified minimum tensile strength value, in megapascals (MPa);
L - The initials of "Liang" in Chinese for frames.
Example 2.BST700L
B - The initials of "Bao" in Baosteel Co., Ltd.;
a) This document number;
b) Product category;
c) Designation, surface treatment method, surface quality level;
d) Specifications and dimensional (thickness, width, unevenness) accuracy;
e) Edge state;
f) Application;
g) Inspection document type.
5.2 Omissions in the order contract
5.2.1 When the surface treatment method is not specified, the rolled surface shall be
delivered.
5.2.2 For hot-rolled steel sheets and strips, when the dimensional accuracy is not
specified, the ordinary accuracy shall be delivered; when the edge state is not specified,
the steel strip shall be delivered in the uncut state, whilst the steel plate shall be
delivered in the cut state.
5.2.3 For hot-rolled pickled steel sheets and strips, when the dimensional accuracy is
not specified, the thickness accuracy shall be delivered in higher thickness accuracy,
whilst other dimensions shall be delivered with ordinary accuracy. When the edge state,
surface quality level and whether oiled are not specified, the steel shall be delivered in
the cut state, higher-grade surface and oiled; when the inner diameter of the steel coil
is not specified, the steel coil shall be delivered with an inner diameter of 610 mm.
6 Dimensions, shape, weight, allowable deviations
The dimensions, shape, weight, allowable deviations of steel sheets and strips shall
comply with the provisions of Q/BQB 301.If the purchaser has higher requirements for
thickness accuracy, the advanced accuracy 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 (melting analysis) of steel shall
comply with the provisions of Table 2 and Table 3.
7.1.2 When Cu, Cr and Ni are residual elements, their contents shall comply with the
7.4.1 The surface treatment methods of steel sheets and steel strips can be rolling
surface and pickling surface.
7.4.2 When the steel sheets and steel strips are hot-rolled pickling surfaces, they are
usually supplied with oil. The oil film shall be removable with alkaline aqueous solution.
Under normal packaging, transportation, loading & unloading, storage conditions, the
supplier shall ensure that the surface of the steel sheets and steel strips will not rust
within 3 months from the date of completion of manufacturing. After negotiation
between the supplier and the buyer and indicated in the contract, the hot-rolled pickling
surface can also be supplied without oil.
Note. For the non-oiled products required by the purchaser, rust may occur, meanwhile the
surface may be easily 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 steel strips shall comply
with the provisions of Table 4, Table 5, Table 6.
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, no test is required.
7.5.3 The impact test is only applicable to products which have a thickness of 6 mm or
more. For products with a thickness greater than 12 mm, the impact specimen size is a
standard specimen of 10 mm × 10 mm × 55 mm; the test result is not less than the
specified value in the Table. For products with a thickness greater than or equal to 6
mm and less than 12 mm, small-sized specimens of 7.5 mm × 10 mm × 55 mm or 5
mm × 10 mm × 55 mm can be used, meanwhile the test results are not less than 75% or
50% of the specified value in the Table, respectively.
7.6 Grain size and banded structure
7.6.1 The grain size of steel sheets and steel strips, which have a thickness of no more
than 8.0 mm, shall be grade 8 or finer. The grain size of steel sheets and steel strips,
which have a thickness of more than 8.0 mm, shall be grade 7 or finer. The grain size
non-uniformity shall be within 3 consecutive different grades. If the supplier can ensure
the quality, no inspection is required.
7.6.2 The banded structure of steel sheets and steel strips shall be no greater than grade
3.If the supplier can ensure the quality, no inspection is required.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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