Q/BQB 312-2023 English PDF

Delivery: 3 seconds. Download true-PDF + Invoice.
Get Quotation: Click Q/BQB 312-2023 (Self-service in 1-minute)
Historical versions (Master-website): Q/BQB 312-2023
Preview True-PDF (Reload/Scroll-down if blank)

Q/BQB 312-2023: Continuously hot-rolled advanced high strength steel sheet and strip for cold forming
Q/BQB 312-2023
BQB®
ENTERPRISE STANDARD OF
BAOSHAN IRON AND STEEL CO., LTD.
Replacing Q/BQB 312-2018
Continuously hot-rolled advanced high strength steel sheet
and strip for cold forming
ISSUED ON: APRIL 09, 2023
IMPLEMENTED ON: JULY 01, 2023
Issued by: Baoshan Iron and Steel Co., Ltd.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Classification and code ... 7
5 Information required for ordering ... 8
6 Dimensions, shape, weight and tolerances ... 9
7 Technical requirements ... 9
8 Inspection and test ... 15
9 Packaging, marking and inspection documents ... 16
10 Rules of rounding off of numerical values ... 17
11 Appendix ... 17
Appendix A (Informative) Comparison table of similar designations between this
document and relevant standards ... 18
Foreword
This document was drafted in accordance with the rules provided in GB/T 1.1-2020
Directives for standardization - Part 1: Rules for the structure and drafting of
standardizing documents.
This document is formulated with reference to EN 10338:2015 and in combination with
Baosteel’s actual situation.
This document replaces Q/BQB 312-2018 Advanced high-strength continuously-hot-
rolled steel sheets and strips for cold forming. Compared with Q/BQB 312-2018, in
addition to structural adjustments and editorial changes, the main technical changes are
as follows:
-- To normative references, add the year number of GB/T 228.1, and change the
year number of GB/T 24524;
-- Change terms and definitions;
-- Add the designation BR780/980HE and corresponding technical requirements;
-- In Table 2, change the lower limit of aluminum content for some designations,
the upper limit of phosphorus for DP600 and the upper limit of manganese for
FB590, and add footnote a for silicon and other element regulations for some
designations;
-- Change the diameter of bending indenter of DP600 in Table 5;
-- Change the provisions of yield strength and elongation after break in Table 6;
-- In Table 7, change the yield strength and tensile strength provisions for FB590,
and change the tensile strength provisions for BR300/450HE and
BR600/780HE;
-- Change the default sampling direction of CP800 tensile test samples in Table
10;
-- Change the elongation after break of SAPH780SF with thickness less than
3.15 mm in Table 11.
Appendix A of this document is an informative appendix.
This document is proposed by the Manufacturing Management Department of Baoshan
Iron and Steel Co., Ltd.
This document is under the jurisdiction of the Manufacturing Management Department
of Baoshan Iron and Steel Co., Ltd.
Continuously hot-rolled advanced high strength steel sheet
and strip for cold forming
1 Scope
This document specifies the dimensions, shape, technical requirements, inspection and
testing, packaging, marking and inspection documents of continuously hot-rolled
advanced high strength steel sheet and strip for cold forming.
This document is applicable to the continuously hot-rolled advanced high strength steel
strip for cold forming produced by Baoshan Iron and Steel Co., Ltd., as well as the
cross-cut steel sheet and longitudinally cut steel strip thereof, hereinafter referred to as
steel sheet and strip.
Note: The advanced high strength steels referred to in this document include the
following steel types: dual phase steel (ferrite + island martensite) (DP), high
hole expansion steel (ferrite + bainite, ferrite or bainite) (HE, or FB, SF),
transformation induced plasticity steel (ferrite + bainite + retained austenite)
(TRIP, or TR), complex phase steel (ferrite + martensite + bainite + precipitation
strengthening) (CP, or MP) and martensitic steel (martensite) (MS).
2 Normative references
The following documents are referred to in the text in such a way that some or all of
their content constitutes requirements of this document. For dated references, only the
version corresponding to that date is applicable to this document; for undated references,
the latest version (including all amendments) is applicable 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 232, Metallic materials - Bend test
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 5028-2008, Metallic materials - Sheet and strip - Determination of tensile
strain hardening exponent
GB/T 8170, Rules of rounding off for numerical values and expression and
judgment of limiting values
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 24524-2021, Metallic materials - Sheet and strip - Hole expanding test
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
The following terms and definitions are applicable to this Standard.
3.1
dual phase steel (DP)
Steel whose microstructure is mainly ferrite and martensite, or a small amount of bainite
and other structures.
Note: Dual phase steel is not only of higher tensile strength level, but also of lower
yield ratio and higher work hardening rate.
3.2
high hole expansion steel (HE)
Steel whose microstructure is mainly “ferrite + bainite” or ferrite (or strengthened
ferrite) or bainite (or strengthened bainite), etc.
e) marginal status;
f) application;
g) type of inspection document.
5.2 Omissions in the order contract
5.2.1 When the surface treatment method is not specified, the steel shall be delivered
with the rolled surface.
5.2.2 For hot-rolled steel sheet and steel strip, if the dimensional accuracy is not
specified, they shall be delivered with ordinary accuracy; if the edge state is not
specified, the steel strip shall be delivered with mill edge and the steel sheet shall be
delivered with cut edge.
5.2.3 For hot-rolled pickled steel sheet and strip, if the dimensional accuracy is not
specified, the thickness shall be delivered with higher thickness accuracy and other
dimensions shall be delivered with ordinary accuracy; if the edge state, surface quality
level and whether oiled are not specified, they shall be delivered with cut edge, higher
quality surface and oiled; if the inner diameter of the steel coil is not specified, it shall
be delivered with an inner diameter of 610 mm.
6 Dimensions, shape, weight and tolerances
6.1 The dimensions, shape, weight and tolerances of steel sheets and strips shall comply
with the provisions of Q/BQB 301. Where the buyer requires higher thickness accuracy,
the advanced accuracy PT.C given in Table 4 of Q/BQB 301 can be selected when
ordering.
6.2 Where there are special requirements for the tolerance of the unevenness of steel
sheets and steel strips, they can be negotiated when ordering and indicated in the
contract.
7 Technical requirements
7.1 Designation and chemical composition
7.1.1 The steel designation and chemical composition (melting analysis) shall comply
with the requirements of Table 2 and Table 3.
7.1.2 The tolerances of chemical composition of finished steel sheets and strips shall
comply with the provisions of GB/T 222.
7.2 Smelting method