Q/BQB 612-2018 English PDF

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Q/BQB 612-2018: Steel plates for building structure
Q/BQB 612-2018
Steel plates for building structure
release
Replace Q/BQB 612-2013
Thick steel plate for building structure
Published on.2018-01-15
2018-04-10 Implementation
Foreword
This standard is drafted in accordance with the rules given in GB/T 1.1-2009 "Standardization Work Guidelines Part I. Standard Structure and Compilation".
This standard is formulated in accordance with JIS G3136.2012 and combined with the actual production situation of Baosteel.
This standard replaces Q/BQB 612-2013 "Thick steel plate for building structure", the main changes compared with the original standard are as follows.
-- The GB/T.20126 reference has been removed from the normative reference file, and the GB/T 2975 number has been added;
-- Strict regulations on the phosphorus and sulfur content of some chemical components.
Appendix A of this standard is an informative annex.
This standard was proposed by the Manufacturing Management Department of Baoshan Iron and Steel Co., Ltd.
This standard was drafted by the Manufacturing Management Department of Baoshan Iron and Steel Co., Ltd.
The drafter of this standard is Huang Jinhua.
The previous versions of the standards replaced by this standard are. Q/BQB 612-2004, Q/BQB 612-2009, Q/BQB 612-2013.
Thick steel plate for building structure
1 Scope
This standard specifies the dimensions, shape, technical requirements, tests and inspections, signs and inspection documents of thick steel plates for building structures.
This standard applies to thick steel plates for building structures produced by Baoshan Iron and Steel Co., Ltd.
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only the dated version applies to this document.
For undated references, the latest edition (including all amendments) applies to this document.
GB/T 223 steel and alloy chemical analysis method
GB/T 228.1 tensile testing of metallic materials - Part 1
GB/T 229 metal material Charpy pendulum impact test method
GB/T 2975-1998 Steel and steel products, mechanical properties test, sampling position and sample preparation
GB/T 4336 Determination of multi-element content of carbon steel and medium-low alloy steels by spark discharge atomic emission spectrometry (conventional method)
GB/T 5313 thickness direction performance steel plate
GB/T.20066 Sampling and sample preparation method for samples for determination of chemical composition of steel and iron
GB/T.20123 Determination of total carbon and sulfur content of steels - Infrared absorption method after high-frequency induction furnace combustion (conventional method)
GB/T.20125 Determination of multi-element content of low alloy steels by inductively coupled plasma atomic emission spectrometry
General technical requirements for Q/BQB 600 thick steel plate
JIS G 0901-1992 Determination of Grade Classification of Rolled Structural Steel and Wide Flat Steel for Construction by Ultrasonic Testing
3 General technical requirements
Unless otherwise specified in this standard, steel plates supplied in accordance with this standard shall comply with the corresponding requirements of the Q/BQB 600 standard.
4 classification and code
The grade, nominal thickness and use of the steel plate are shown in Table 1.
Table 1
Brand nominal thickness mm
SN400A, SN400B, SN490B 6~100
Building structure
SN400C, SN490C 16~100
5 Dimensions, shape, weight and tolerance
Dimensions, shapes, weights and tolerances shall be in accordance with Q/BQB 600, where the thickness tolerance level is in accordance with PT.B.
6 Technical requirements
6.1 Grades and chemical composition
6.1.1 The grade and chemical composition of the steel (melting analysis) shall comply with the requirements of Table 2.
Table 2
Brand nominal thickness mm
Chemical composition (melting analysis) %
C Si Mn PS other
SN400A 6～100 ≤0.24 - - ≤0.025 ≤0.020
As needed
Add other
Gold element
SN400B
6～50 ≤0.20
≤0.35 0.60～1.50 ≤0.025 ≤0.015
>50～100 ≤0.22
SN400C
16～50 ≤0.20
≤0.35 0.60～1.50 ≤0.020 ≤0.008
>50～100 ≤0.22
SN490B
6～50 ≤0.18
≤0.55 ≤1.65 ≤0.025 ≤0.015
>50～100 ≤0.20
SN490C
16～50 ≤0.18
≤0.55 ≤1.65 ≤0.020 ≤0.008
>50～100 ≤0.20
6.1.2 The formula for calculating the carbon equivalent and welding crack sensitivity coefficient shall comply with Table 3.
table 3
Project calculation formula a
Carbon equivalent 14
Mo
Cr
Ni
Si
MnCeq C
Welding crack sensitivity coefficient B510
Mo
Cr
Ni
Cu
Mn
SiCPcm 
a Calculate the chemical composition of the formula using the value of the smelting analysis
6.1.3 The carbon equivalent of steel plates (excluding mechanically controlled rolling conditions) shall comply with the requirements of Table 4.
Table 4
Brand
Carbon equivalent Ceq, %
Thickness, mm
≤40 >40～100
SN400B, SN400C ≤0.36 ≤0.36
SN490B, SN490C ≤0.44 ≤0.46
6.1.4 According to the requirements of the purchaser, the carbon of the steel plate (excluding the mechanically controlled rolling state delivery) shall be negotiated between the supplier and the buyer and indicated in the contract.
The amount can be replaced by the welding crack sensitivity coefficient, and the welding crack sensitivity coefficient should meet the requirements of Table 5.
table 5
Grade welding crack sensitivity coefficient Pcm,%
SN400B, SN400C ≤0.26
SN490B, SN490C ≤ 0.29
6.1.5 According to the requirements of the purchaser, the carbon equivalent of the steel plate delivered by the thermomechanical controlled rolling state shall be negotiated between the supplier and the purchaser and indicated in the contract.
Should comply with the provisions of Table 6.
Table 6
Grade delivery status
Carbon equivalent Ceq, %
Thickness, mm
≤50 >50～100
SN490B, SN490C TM ≤0.38 ≤0.40
6.1.6 According to the requirements of the purchaser, the carbon equivalent of the steel plate delivered by the thermomechanical controlled rolling state shall be negotiated between the supplier and the purchaser and indicated in the contract.
It can be replaced by the welding crack sensitivity coefficient, and the welding crack sensitivity coefficient should meet the requirements of Table 7.
Table 7
Grade delivery status
Welding crack sensitivity coefficient Pcm,%
Thickness, mm
≤50 >50～100
SN490B, SN490C TM ≤0.24 ≤0.26
6.2 Mechanical and process properties
6.2.1 The mechanical and process properties of the steel plate are to comply with the requirements of Table 8.
6.2.2 Shock absorption energy is the average of the test results of a group of three samples, allowing the test result of one of the samples to be less than the specified value, but
Not less than 70% of the specified value.
6.2.3 The impact test is only applicable to steel plates with a thickness of 6 mm or more. When impact test is carried out on steel plates with a thickness of 12 mm or more,
Using 10.0mm × 10.0mm × 55mm standard specimens, the test results should meet the specified values in the table; for thickness greater than or equal to 6mm and less than
When the 12.0mm steel plate is subjected to the impact test, an auxiliary sample of 7.5mm × 10.0mm × 55mm or 5.0mm × 10.0mm × 55mm shall be used.
The test results are not less than 75% or 50% of the values specified in the table.
6.2.4 If the impact test results do not meet the specified requirements, three additional samples may be taken on the same sampled product for testing.
The average value of the samples should not be less than the specified value, and the sample below the specified value can only have at most two samples, and only one of the values is allowed to be smaller than
70% of the specified value.
6.3 Ultrasonic inspection
6.3.1 For grades SN400C and SN490C, ultrasonic inspection shall be carried out one by one. The inspection method and acceptance level shall comply with the requirements of Table 9.
6.3.2 For the grades SN400B and SN490B, according to the requirements of the purchaser, after the supply and demand sides negotiate and indicate in the contract, the ultrasound can be carried out one by one.
Inspection, inspection methods and acceptance levels are in accordance with Table 9.
Table 9
Grade thickness mm inspection method and acceptance criteria
SN 400B, SN 490B 13~100 according to JIS G 0901
Accept the standard Y-level regulations SN 400C, SN 490C 16-100
7 Inspection and testing
7.1 Types of inspection documents shall comply with the provisions of 7.2 to 7.4 when selecting the specified inspection and test.
7.2 The number of samples, sampling methods and test methods required for each batch of steel plate inspection items shall comply with the requirements of Table 10.
Table 10
No. Test item number of samples, one sampling method b test method
1 Chemical analysis a 1 (per furnace) GB/T.20066 GB/T 223, GB/T 4336, GB/T.20123, GB/T.20125 or general method
2 Tensile test 1 GB/T 2975 GB/T 228.1
3 Impact test 1 group (3)
GB/T 2975
Thickness ≤ 28mm, Figure A11 a) (near surface)
Thickness > 28mm, Figure A11 b) (1/4t)
GB/T 229
4 Tensile performance test in thickness direction 1 group (3) GB/T 5313 GB/T 228.1
5 Ultrasonic inspection one by one - JIS G 0901
a When arbitrating, the test method adopts GB/T 223.
b When it is not possible to sample at the specified sampling position, it should be as close as possible to that position.
7.3 Sampling frequency
7.3.1 Sampling frequency of chemical composition analysis
Melting analysis of chemical components by furnace.
7.3.2 Sampling frequency of tensile properties
Each batch shall be composed of steel plates with a weight not greater than 50 tons, the same furnace number, the same grade, a maximum thickness not greater than 2 times the minimum thickness, and the same delivery status.
to make. When the batch weight is greater than 50 tons, take two samples. When the batch consists of a single sheet of steel, take one sample.
7.3.3 Sampling frequency of impact performance
Each batch shall consist of steel plates of the same furnace number, the same grade, and the same delivery status. The specimen shall be taken from the thickest steel plate in the batch.
7.3.4 Sampling frequency for thickness direction performance
When the delivery status is heat treatment, each batch consists of the same rolling mother board with the same heat treatment system; when the delivery status is not heat treatment, each batch
It consists of the same rolling mother board.
7.3.5 The negotiation rules may be determined separately by negotiation between the supplier and the buyer.
7.4 Re-inspection
7.4.1 Retest of impact test
If the impact test results do not meet the specified requirements, the single-plate steel that has been tested and the results are not acceptable cannot be accepted, and is the same as the sampled steel plate.
The thickness of the steel plate is submitted to the impact test and acceptance one by one, and the impact test and acceptance are submitted to the new batch of steel plates of other thicknesses.
7.4.2 Re-test of thickness direction performance
If the average value of the three specimens in the thickness direction performance or a single value does not meet the requirements of Table 8, take another three specimens from the same billet.
Re-inspection, when the average of the six samples and the single values of the three re-inspection samples are in accordance with Table 8, the retest is qualified.
8 Appendix
Appendix A (informative appendix) lists the comparison table of this standard with the reference standard and the national standard.
Appendix A
(informative appendix)
This standard is compared with the reference standard and the national standard.
Table A.1
SN400A SN400A - -
SN400B SN400B S235S Q235GJC
SN400C SN400C S235S-Z25(UT) Q235GJC-Z25
SN490B SN490B S325S Q345GJC
SN490C SN490C S325S-Z25(UT) Q345GJC-Z25