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This standard is developed in accordance with the rules given in GB/T 1.1-2009 Directives for Standardization —Part 1: Structure and Drafting of Standards.
This standard is formulated on the base of JIS G3113-2006, JIS G3134-2006, EN 10149-2:2013, YB/T 4151-2006 and GB/T 3273-2005, and in combination with the actual situation of Baosteel.
This standard replaces Q/BQB 310-2009 and BZJ 310-2012. The following technical deviations have been made with respect to Q/BQB 310-2009 (the previous edition):
— Editions of normative references are updated;
— Addition: designations QStE550TM, QStE600TM, QStE650TM, QStE700TM and corresponding technical requirements;
— Addition: designations B450CL, B500CL, B550CL, B600CL, B650CL and corresponding technical requirements;
— Addition: designations B600L, B650L, B700L, B750L and corresponding technical requirements;
— The nominal thickness ranges of partial designations in Table 1 are extended;
— Adjustment: the upper limits of chemical composition Mn content of partial designations in Table 2;
— Correction: the misprint of SPFH590;
— Addition: the corresponding relationship between newly-added designations in the comparison table of similar standards in Annex A;
— Other editorial changes.
This standard was proposed by manufacture and management department of Baoshan Iron & Steel Co., Ltd.
This standard was prepared by manufacture and management department of Baoshan Iron & Steel Co., Ltd.
This standard was drafted by manufacture and management department of Baoshan Iron & Steel Co., Ltd.
Chief drafting staff of this standard: Han Yu.
The previous editions of this standard are as follows: Q/BQB 310-1989, Q/BQB 310-1994, Q/BQB 310-1999, Q/BQB 310-2003, Q/BQB 310-2009.
Continuously Hot-rolled Steel Sheet and Strip for Automobile Structural Use
1 Scope
This standard specifies the size, appearance, technical requirements, test and inspection, package, mark and inspection document of continuously hot-rolled steel sheet and strip for automobile structural use.
This standard is applicable to continuously hot-rolled steel strip of cold rolled quality carbon structural/low-alloy structural steel, as well as transversally cut steel sheet and longitudinally cut steel strip (hereinafter referred to as steel sheet and strip) produced by Baoshan Iron & Steel Co., Ltd. The products are used for manufacturing of automobile frames, beams, roller wheels, automobile transmission shaft pipes, automobile axle housing and other structure.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 222-2006 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 223 Methods for Chemical Analysis of Iron, Steel and Alloy
GB/T 228.1-2010 Metallic Material — Tensile Test — Part 1: Method of Test at Room Temperature
GB/T 232-2010 Metallic Materials — Bend Test
GB/T 2975-1998 Steel and Steel Products — Location and Preparation of Test Pieces for Mechanical Testing
GB/T 4336-2002 Test Method for Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low-alloy Steel (Routine Method)
GB/T 8170-2008 Rules of Rounding Off for Numerical Values & Expression and Judgement of Limiting Values
GB/T 20066-2006 Steel and Iron — Sampling and Preparation of Samples for the Determination of Chemical Composition
GB/T 20123-2006 Steel and Iron — Determination of Total Carbon and Sulfur Content — Infrared Absorption Method after Combustion in an Induction Furnace (Routine 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 Classification and Designation
3.1 The designation, nominal thickness and application of steel sheet and strip as shown in Table 1.
3.2 The products may be classified into the following types according to surface treatment mode:
Pickled surface
Rolled surface
3.3 The products may be classified into the following types according to surface quality grade:
Ordinary grade surface FA
High grade surface FB
3.4 The products may be classified into the following types according to product category:
Hot-rolled steel strip
Hot-rolled steel sheet
Hot-rolled longitudinally cut steel strip
Hot rolled acid pickling steel strip
Hot rolled pickled plate
Table 1
Designation Nominal thickness a mm Purpose
SAPH310 1.5 to 16.0 Used for automobile frameworks, wheels and other structural parts that required forming performance
SAPH370 1.5 to 12.5
SAPH400 1.5 to 12.0
SAPH440 1.5 to 8.0
SPFH540 SPFH590 1.8 to 6.0 Used for automobile frameworks, wheels and other structural parts that required fine forming performance and high strength
QStE340TM, QStE380TM
QStE420TM, QStE460TM
QStE500TM, QStE550TM
1.5 to 14.0 Used for automobile frames and other structural parts that required fine cold forming performance and high or higher strength
QStE600TM, QStE650TM QStE700TM 1.5 to 12.0
B330CL
1.5 to 14.0
Used for manufacturing of automobile wheel rims and wheel spokes that required fine cold forming performance
B380CL
B420CL
B450CL
B500CL
B550CL
B600CL
B650CL
B320L 1.5 to 8.0
Used for manufacturing of automotive frames and beams
B420L 2.0 to 8.0
B510L 2.0 to 14.0
B510DL 4.0 to 8.0
B550L
B600L
B650L
B700L
B750L
2.0 to 12
B440QZR 3.0 to 8.0 Used for manufacturing of automobile transmission shaft pipe
B480QZR 4.0 to 8.0
B440QK 3.0 to 8.0 Used for manufacturing of automobile axle housing
a As for steel sheet and strip with hot rolled pickled surface, nominal thickness ≤6.0 mm.
4 Ordering Information
4.1 The user shall provide the following information for ordering:
a) Standard number of the enterprise;
b) Product category;
c) Designation, surface treatment mode and surface quality grade;
d) Specification and size (thickness) accuracy;
e) Edge conditions;
f) Purpose;
g) Inspection document type.
4.2 Omitted items in procurement contract
4.2.1 Where surface treatment mode is not indicated, the products with rolled surface shall be delivered.
4.2.2 For hot-rolled steel sheet and strip, where the dimensional precision is not indicated, unless otherwise specially specified in this standard, the products may be delivered in the normal thickness precision specified in Q/BQB 301; where the edge conditions are not indicated, steel strip shall be delivered in untrimmed condition, and steel sheet delivered in trimmed condition.
4.2.3 As for hot rolled pickled sheet and strip, unless otherwise specially specified in this standard, the products with high thickness accuracy specified in Q/BQB 301 shall be delivered; where edge condition, surface quality grade and greasing requirements are not indicated, the greased products with cut side and high grade surface shall be delivered; where inner diameter of steel coil is not indicated, the products with 610 mm in inner diameter of steel coil shall be delivered.
5 Dimension, Appearance, Weight and Permissible Deviation
5.1 The permissible thickness deviation of B330CL to B650CL, B440QZR and B480QZR shall be in accordance with the higher precision (PT.B) specified in Q/BQB 301.
5.2 Other dimension, appearance, weight and permissible deviations shall be in accordance with Q/BQB 301.
6 Technical Requirements
6.1 Designation and chemical composition
6.1.1 Designation and chemical composition (melting analysis) of steel shall be in accordance with those specified in Tables 2 through 4.
6.1.2 The content of residual elements in steel shall be in accordance with the following requirements: Cu ≤ 0.20%, Cr ≤ 0.15% and Ni ≤ 0.15%. However, the chemical analysis of these elements can be not carried out when the supplier can guarantee the content of the residual elements Cu, Cr, Ni in steel in accordance with such requirements.
6.1.3 The permissible deviation for chemical composition of finished product of steel sheet and strip shall be in accordance with GB/T 222.
6.2 Smelting process
The steel used for steel sheet and strip shall be killed steel smelted by oxygen converter.
6.3 Delivery state
Steel sheet and strip shall be delivered in hot rolled or control rolled state.
Table 2
Designation Chemical composition a (mass fraction), %
C Si Mn P S Alt
SAPH310 ≤0.10 ≤0.30 ≤0.60
≤0.035
≤0.035
≥0.010
SAPH370 ≤0.21 ≤0.30 ≤0.75
SAPH400
≤0.21
≤0.30 ≤1.40
≤0.030
≤0.025
SAPH440 ≤1.60
SPFH540 ≤0.15 ≤0.50 ≤1.80
≤0.025
≤0.025
SPFH590 ≤0.18 ≤0.60 ≤2.00
B440QK ≤0.21 ≤0.35 ≤1.80 ≤0.030 ≤0.025
B330CL ≤0.10 ≤0.30 ≤0.60
≤0.030
≤0.025
B380CL ≤0.12 ≤0.30 ≤1.20
B420CL ≤0.12 ≤0.30 ≤1.50
B450CL ≤0.10 ≤0.30 ≤1.50 ≤0.030 ≤0.025
B500CL ≤0.12 ≤0.30 ≤1.50 ≤0.030 ≤0.025
B550CL ≤0.12 ≤0.30 ≤2.00 ≤0.030 ≤0.025
B600CL ≤0.15 ≤0.30 ≤2.00 ≤0.030 ≤0.025
B650CL ≤0.15 ≤0.50 ≤2.00 ≤0.030 ≤0.025
B320L ≤0.10 ≤0.30 ≤0.60
≤0.030 ≤0.035
B420L ≤0.12 ≤0.50 ≤1.50 ≤0.025
B510L ≤0.16 ≤0.50 ≤1.60 ≤0.025
B510DL ≤0.18 ≤0.30 ≤1.60 ≤0.025 ≤0.020
B550L ≤0.16 ≤0.50 ≤1.60 ≤0.030 ≤0.025
B440QZR ≤0.12 ≤0.50 ≤1.30
≤0.030 ≤0.025
-
B480QZR ≤0.16 ≤0.50 ≤1.50 ≤0.035
a As required, other alloy elements may be added to improve the steel performance, and the lower limit of Alt is not required at this point.
Table 3
Designation Chemical composition a (mass fraction), %
C Si Mn P S Alt Other
QStE340TM
≤0.12
≤0.50 ≤1.30
≤0.030
≤0.025
≥0.015
Nb≤0.09 V≤0.20 Ti≤0.15
QStE380TM ≤1.40
QStE420TM ≤1.50
QStE460TM ≤1.60
QStE500TM ≤1.70
a As required, one or more alloy elements of Nb, V and Ti may be added to improve the steel performance; however, Nb+V+Ti ≤ 0.22%.
Table 4
Designation Chemical composition a (mass fraction) (%)
C Mn Si P S Alt Nb a V a Ti a Mo B
QStE550TM B600L ≤0.12 ≤1.80 ≤0.50 ≤0.025 ≤0.015 ≥0.015 ≤0.09 ≤0.20 ≤0.15 - -
QStE600TM B650L ≤0.12 ≤1.90 ≤0.50 ≤0.025 ≤0.015 ≥0.015 ≤0.09 ≤0.20 ≤0.22 ≤0.50 ≤0.005
QStE650TM B700L ≤0.12 ≤2.00 ≤0.60 ≤0.025 ≤0.015 ≥0.015 ≤0.09 ≤0.20 ≤0.22 ≤0.50 ≤0.005
QStE700TM B750L ≤0.12 ≤2.10 ≤0.60 ≤0.025 ≤0.015 ≥0.015 ≤0.09 ≤0.20 ≤0.22 ≤0.50 ≤0.005
a One or more alloy elements of Nb, V and Ti may be added in the steel; however, Nb+V+Ti ≤ 0.22%.
6.4 Surface treatment mode
6.4.1 Surface of steel sheet and strip may be treated by rolling and pickling.
6.4.2 Steel and steel strip with pickling surface may be delivered with or without oil coating. As for steel sheet and strip with oil coating and picking surface, under the normal condition of package, transportation, handle and storage, the supplier ensures that no rust occurs within three months from the date of production, and the oil coating can be removed with alkaline water solution. If the pickled steel sheet and strip delivered with oil coating is required by the purchaser, it shall be indicated in the ordering contract. Pickled steel sheet and strip without oil coating are prone to rust and abrasion during transportation and processing, and the supplier does not guarantee this.
1 Scope
2 Normative References
3 Classification and Designation
4 Ordering Information
5 Dimension, Appearance, Weight and Permissible Deviation
6 Technical Requirements
7 Inspection and Test
8 Package, Mark and Inspection Document
9 Rules for Rounding off of Numerical Values
10 Annex
Annex A (Informative) Comparison Table for Similar Designations between This Standard and Relevant Standards
