GB/T 712-2022 (GB/T712-2022, GBT 712-2022, GBT712-2022) & related versions
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GB/T 712-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.50
CCS H 46
Replacing GB/T 712-2011
Structural Steel for Ship and Ocean Engineering
ISSUED ON: OCTOBER 12, 2022
IMPLEMENTED ON: MAY 1, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 7
4 Classification and Designations ... 7
5 Order Content ... 8
6 Dimensions, Shapes and Weights ... 8
7 Technical Requirements ... 9
8 Test Methods ... 21
9 Inspection Rules ... 23
10 Packaging, Marking and Quality Certificate ... 26
Appendix A (informative) Correspondence of Each Steel Grade and Designation
Specified in the Regulations of Each Classification Society ... 27
Appendix B (normative) Steel Designations, Delivery Status and Batch Size for Impact
Test ... 31
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 serves as a replacement of GB/T 712-2011 Ship and Ocean Engineering
Structural Steel. In comparison with GB/T 712-2011, apart from structural adjustments and
editorial modifications, the main technical changes are as follows:
a) The applicable thickness range of structural steel for ocean engineering is modified
(see Chapter 1; Chapter 1 of Version 2011);
b) A total of 3 steel grades and 10 designations of ultra-high strength 790, 890 and 960
are added (see Chapter 4);
c) The requirements for the average thickness of steel plates are added (see 6.1);
d) The requirements for the chemical composition of ultra-high strength grade steel are
modified (see Table 4; Table 4 of Version 2011);
e) The requirements for carbon equivalent of ultra-high strength steel are added (see
Table 5);
f) The requirements for vacuum degassing treatment of ultra-high strength grade steel
with through-thickness properties and 690, 790, 890 and 960 grade steel with non-
through-thickness properties are added (see 7.2);
g) The requirements for the rolling compression ratio of continuous cast billets and steel
ingots are added (see 7.2);
h) The requirements for the mechanical properties of ultra-high strength grade steel are
modified (see Table 7; Table 6 of Version 2011);
i) The requirements for the grain size of ultra-high strength grade steel are added (see
7.5);
j) The measurement method for the average thickness of steel plates is added (see 8.2);
k) The requirements for the sampling location of ultra-high strength grade steel are
modified (see 8.3; 7.4 of Version 2011);
l) The requirements for the batching of ultra-high strength grade steel are modified (see
9.2; 7.3 of Version 2011);
m) The requirements for impact inspection lot of ultra-high strength grade steel are
modified (see Appendix B; Appendix A of Version 2011);
Structural Steel for Ship and Ocean Engineering
1 Scope
This document specifies the classification and designations, order content, dimensions, shapes,
weights, technical requirements, test methods, inspection rules, packaging, marking and quality
certificate of structural steel for ship and ocean engineering.
This document is applicable to steel plates (with a thickness of not greater than 150 mm) for
the manufacturing of hull structures, such as: ocean-going, coastal and inland navigation ships
and fishing boats, etc., steel plates (with a thickness of not greater than 250 mm) for ocean
engineering structures, steel strips and shear plates with a thickness of not greater than 25.4 mm,
and profile steel with a thickness of not greater than 50 mm or steel bars with a diameter of not
greater than 50 mm (hereinafter referred to as the steel).
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 222 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 223.5 Steel and Iron - Determination of Acid-soluble Silicon and Total Silicon Content -
Reduced Molybdosilicate Spectrophotometric Method
GB/T 223.9 Iron, Steel and Alloy - Determination of Aluminum Content - Chrome Azurol S
Photometric Method
GB/T 223.12 Methods for Chemical Analysis of Iron, Steel and Alloy - The Sodium Carbonate
Separation-diphenyl Carbazide Photometric Method for the Determination of Chromium
Content
GB/T 223.14 Methods for Chemical Analysis of Iron, Steel and Alloy - The N-benzoy-N-
phenylhydroxylamine Extraction Photometric Method for the Determination of Vanadium
Content
GB/T 223.19 Methods for Chemical Analysis of Iron, Steel and Alloy - The Neocuproine-
chloroform Extraction Photometric Method for the Determination of Copper Content
GB/T 223.23 Iron, Steel and Alloy - Determination of Nickel Content - The Dimethylglyoxime
Spectrophotometric Method
GB/T 223.25 Methods for Chemical Analysis of Iron, Steel and Alloy - The Dimethylglyoxime
Analysis of Carbon and Low-alloy Steel (routine method)
GB/T 5313 Steel Plate with Through-thickness Properties
GB/T 6394 Determination of Estimating the Average Grain Size of Metal
GB/T 8170 Rule of Rounding off for Numerical Values & Expression and Judgement of
Limiting Values
GB/T 11261 Steel and Iron - Determination of Oxygen Content - The Pulse Heating Inert Gas
Fusion-infrared Absorption Method
GB/T 17505 Steel and Steel Products - General Technical Delivery Requirements
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 20124 Steel and Iron - Determination of Nitrogen Content - Thermal Conductimetric
Method after Fusion in a Current of Inert Gas (routine method)
GB/T 20125 Low-alloy Steel - Determination of Multi-element Contents - Inductively Coupled
Plasma Atomic Emission Spectrometric Method
3 Terms and Definitions
The terms and definitions defined in GB/T 1591 are applicable to this document.
4 Classification and Designations
4.1 The classification and designations of the steel shall comply with the stipulations of Table
1. Please refer to Appendix A for a comparison of the various steel grades and designations
specified in the regulations of each classification society.
4.2 When there are requirements for the through-thickness properties of the steel, the symbols
for the required levels of through-thickness properties (Z25 and Z35) shall be added after the
designations in Table 1.
do not hinder the inspection of the surface quality, as well as inconspicuous roughness,
reticulation, scratches and other local defects caused by pressing the iron oxide scales and
rollers, but their depth shall not be greater than 0.3 mm, and the minimum allowable thickness
of the steels shall be guaranteed.
7.6.3 Surface defects of the steels are allowed to be removed by grinding. The cleaned area
shall be smooth and without edges. The thickness reduction shall not be greater than 7% of the
nominal thickness and not greater than 3 mm, whichever is smaller; the single grinding area
shall not be greater than 0.25 m2, and the sum of local grinding areas shall not be greater than
2% of the total area. The distance between two grinding surfaces shall be greater than their
average width, otherwise, it is considered to be one grinding surface. Welding repairs shall
comply with the regulations of China Classification Society. Magnetic particle testing or
penetrant testing shall be adopted to confirm complete removal of defects.
7.6.4 For steel strips, since there is no opportunity to remove the defect part of the surface strip,
certain defects are allowed on the surface, but the length of the defective part of each coil of
steel strip shall not be greater than 6% of the total length of the steel strip.
7.7 Non-destructive Inspection
7.7.1 Steel plates with through-thickness properties shall be subjected to ultrasonic inspection.
The inspection method is GB/T 2970 or other methods. The test method and qualification level
shall be indicated in the contract.
7.7.2 In accordance with the requirements of the demand-side, through negotiation between the
supply-side and the demand-side, and statement in the contract, other steel plates may also be
subjected to non-destructive inspection.
8 Test Methods
8.1 Chemical Composition
Generally speaking, the chemical composition of steel shall be tested in accordance with GB/T
4336, GB/T 20123, GB/T 20124, GB/T 20125 or other universal methods. The arbitration shall
be conducted in accordance with the stipulations of GB/T 223.5, GB/T 223.9, GB/T 223.12,
GB/T 223.14, GB/T 223.19, GB/T 223.23, GB/T 223.25, GB/T 223.26, GB/T 223.37, GB/T
223.40, GB/T 223.62, GB/T 223.63, GB/T 223.67, GB/T 223.69, GB/T 223.78, GB/T 223.84,
GB/T 11261 or GB/T 20125.
8.2 Thickness Measurement
8.2.1 The thickness measurement parts of steel plates and steel strips shall comply with the
stipulations of GB/T 709.
8.2.2 The average thickness measurement method for the steel plates:
9.2 Batching Rules
9.2.1 Steels shall be accepted in batches. For general-strength and high-strength steel grades,
each batch shall be composed of steels of the same designation, the same heat number, the same
delivery status, and with a thickness difference (or diameter difference) less than 10 mm; for
ultra-high strength steels, each batch shall be composed of steels of the same designation, the
same heat number, the same delivery status, and the same thickness (or the same diameter).
9.2.2 In terms of the tensile test, for general-strength and high-strength steel grades, the weight
of each batch of steels is not greater than 50 t; for ultra-high strength steel grades, the weight
of each batch of steels is not greater than 25 t. In terms of the impact test, the batch size shall
comply with the stipulations of Appendix B.
9.2.3 Steels with through-thickness properties shall be accepted as rolled billets. When the
sulfur content of Z25 steel is not greater than 0.005%, it can be inspected in batches, and the
weight of each batch is not greater than 50 t.
9.3 Sampling Quantity
The sampling quantity and sampling method of each batch of steels are shown in Table 9.
9.4 Re-inspection and Determination
9.4.1 Re-inspection and determination of tensile test
The re-inspection and determination of the tensile test of the steels shall comply with the
stipulations of GB/T 17505.
9.4.2 Re-inspection and determination of reduction of area in thickness direction of steels
with through-thickness properties
Figure 2 specifies three situations, in which, re-inspection is allowed. Under these
circumstances, the remaining 3 spare specimens need to be tested. The average value of 6
specimens shall be greater than the specified minimum average value, and the results below the
average value shall not be more than 2 but shall not be lower than the minimum single value
specified in Table 8, otherwise, the batch of steels will not be accepted.
......
GB 712-2011
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.50
H 46
Replacing GB 712-2000
Ship and Ocean Engineering Structural Steel
ISSUED ON. JUNE 16, 2011
IMPLEMENTED ON. FEBRUARY 1, 2012
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of
China.
3. No action is required - Full-copy of this standard will be automatically &
immediately delivered to your EMAIL address in 0~60 minutes.
Table of Contents
Foreword ... 3
1 Application Scope ... 5
2 Normative References ... 5
3 Classification and Designations ... 7
4 Ordering Content ... 8
5 Dimensions, Shapes, Weights and Tolerances ... 8
6 Requirements ... 8
7 Inspection and Test ... 13
8 Packaging, Marking and Quality Certification ... 16
9 Rounding-off of Numerical Values ... 16
Annex A (Normative) Designations, Delivery Conditions and Impact Test
Batches of Steels ... 17
Annex B (Informative) ... 20
Table of Correspondence of All Grades and Designations of Steels Used for
Hull Specified in the Rules of All Classification Societies ... 20
Foreword
Articles 2, 3 and 4, 6.6.2 and Annex B of this Standard are voluntary; the others
are compulsory.
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
In this Standard, GB 712-2000, Hull Structural Steel, was revised by referring to the
rule of China Classification Society (CCS), Rules for Materials and Welding.
GB 712-2000, Hull Structural Steel, is abolished from the date of the implementation
of this Standard.
Compared with GB 712-2000, the major changes of this Standard are as follows.
-- the standard name is modified;
-- the ordering content is added;
-- 24 designations of 6 steel grades and two grades of Z25 and Z35 of Z-direction
steel are added;
-- the harmful elements such as P and S in steels are under strict control;
-- the chemical compositions and mechanical properties of 24 designations of high
strength and super strength steel grades are added;
-- the provision on the surface quality repair-grinding area is added;
-- the allowable abnormal part of the surface quality of steel strips is reduced to 6%;
-- the Article of “Rounding-off of Numerical Values” is added;
-- Annex A (Designations, Delivery Conditions and Impact Test Batches) and Annex
B (Table of Correspondence of All Grades and Designations of Steels Used for
Hull Specified in the Rules of All Classification Societies) are added.
Annex A of this Standard is normative; Annex B is informative.
This Standard was proposed by China Iron and Steel Association.
This Standard shall be under the jurisdiction of the National Standardization Technical
Committee on Steels.
The drafting organizations of this Standard. Ansteel Co., Ltd., China Metallurgical
Information and Standardization Institute, Chongqing Iron and Steel Co., Ltd., Xinyu
Iron and Steel Group Co., Ltd., Tianjin Iron and Steel Group Co., Ltd., Nanjing Iron and
Steel Co., Ltd., Xiangtan Iron and Steel Co., Ltd. of Hunan Valin, Jiangsu Shagang
Group Co., Ltd., Shugang Group, Hunan Valin LY STEEL Co., Ltd., China
Ship and Ocean Engineering Structural Steel
1 Application Scope
This Standard specifies the classification and designations, ordering content,
dimensions, shapes, weights and tolerances, requirements, inspection and test, and
packaging, marking and quality certification of ship and ocean engineering structural
steel.
This Standard applies to steel plates of thickness not greater than 150 mm, steel strips
and shear plates of thickness not greater than 25.4 mm and profile steels of thickness
or diameter not greater than 50 mm (hereinafter referred to as steels), which are used
to manufacture the ships of ocean, coastal and inland water voyages, fishing boats
and ocean engineering structures.
2 Normative References
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition dated applies to this document. For
undated references, the latest edition of the referenced documents (including all
amendments) applies to this Standard.
GB/T 222, Permissible Tolerances for Chemical Composition of Steel Products
GB/T 223.5, Steel and Iron – Determination of Acid-soluble Silicon and Total Silicon
Content – Reduced Molybdosilicate Spectrophotometric Method
GB/T 223.9, Iron, Steel and Alloy – Determination of Aluminium Content – Chrom
Azurol S Photometric Method
GB/T 223.12, Methods for Chemical Analysis of Iron, Steel and Alloy – The Sodium
Carbonate Separation-Diphenyl Carbazide Photometric Method for the
Determination of Chromium Content
GB/T 223.14, Methods for Chemical Analysis of Iron, Steel and Alloy – The N-
Benzoy-N-Phenylhydroxylamine Extraction Photometric Method for the
Determination of Vanadium Content
GB/T 223.16, Methods for Chemical Analysis of Iron, Steel and Alloy – The
Chromotropic Acid Photometric Method for the Determination of Titanium Content
GB/T 223.19, Methods for Chemical Analysis of Iron Steel and Alloy – The
Neocuproine-Chloroform Extraction Photometric Method for the Determination of
Copper Content
GB/T 223.23, Iron, Steel and Alloy – Determination of Nickel Content – The
Dimethylglyoxime Spectrophotometric Method
GB/T 223.25, Methods for Chemical Analysis of Iron, Steel and Alloy – The
Dimethylglyoxime Gravimetric Method for the Determination of Nickel Content
GB/T 223.26, Iron, Steel and Alloy – Determination of Molybdenum Content – The
Thiocyanate Spectrophotometric Method
GB/T 223.37, Methods for Chemical Analysis of Iron, Steel and Alloy – The
Indophenol Blue Photometric Method for the Determination of Nitrogen Content
after Distillation Separation
GB/T 223.40, Iron, Steel and Alloy – Determination of Niobium Content by the
Sulphochlorophenol S Spectrophotometric Method
GB/T 223.62, Methods for Chemical Analysis of Iron, Steel and Alloy – The Butyl
Acetate Extraction Photometric Method for the Determination of Phosphorus
Content
GB/T 223.63, Methods for Chemical Analysis of Iron, Steel and Alloy – The Sodium
(Potassium) Periodate Photometric Method for the Determination of Manganese
Content
GB/T 223.67, Iron, Steel and Alloy – Determination of Sulfur Content – Methylene
Blue Spectrophotometric Method
GB/T 223.69, Iron, Steel and Alloy – Determination of Carbon Contents – Gas-
volumetric Method after Combustion in the Pipe Furnace
GB/T 228.1, Metallic Materials – Tensile Testing – Part 1. Method of Test at Room
Temperature (GB/T 228.1-2011, ISO 6892-1.2009, MOD)
GB/T 229, Metallic Materials – Charpy Pendulum Impact Test Method
GB/T 247, General Rule of Package, Mark and Certification for Steel Plates (Sheets)
and Strips
GB/T 709, Dimensions, Shape, Weight and Tolerances for Hot Rolled Steel Sheets
and Strips
GB/T 2101, General Requirement of Acceptance, Packaging, Marking and
Certification for Section Steel
GB/T 2970, Thick Steel Plates - Method for Ultrasonic Inspection
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
4 Ordering Content
4.1 The contract or order placed in accordance with this Standard shall include the
following content.
a) a reference to this Standard;
b) designation;
c) specification;
d) weight;
e) dimensions and accuracy of dimensions and shapes;
f) delivery condition;
g) marking;
h) special requirements.
4.2 When the content of e) ~ g) is not specified in the ordering contract, it may be
decided by the supplier.
5 Dimensions, Shapes, Weights and Tolerances
The dimensions, shapes, weights and tolerances of tinplate shall be as specified in
GB/T 709; and the lower deviation of thickness is -0.30 mm. The dimensions, shapes,
weights and tolerances of profile steels shall be as specified in relevant standards.
6 Requirements
6.1 Designations and chemical compositions
6.1.1 The designations and chemical compositions (ladle analysis) of steels of
general strength and high strength shall be as specified in Table 2. The carbon
equivalent maximum value of steels of high strength delivered under the condition of
TMCP shall be as specified in Table 3.
6.1.2 The designations and chemical compositions (ladle analysis) of steels of super
strength shall be as specified in Table 4.
6.1.3 The tolerances for the chemical compositions of steels shall be as specified in
GB/T 222.
thickness direction of Z-direction
steel
5 Ultrasonic flaw detection testing Per sheet - GB/T 2970
6 Surface quality Per sheet/per pcs - Visual inspection and measurement
7 Dimensions, shape ...
......
| Standard ID | GB/T 712-2022 (GB/T712-2022) | | Description (Translated English) | Structural steel for ship and ocean engineering | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | H46 | | Classification of International Standard | 77.140.50 | | Word Count Estimation | 25,255 | | Date of Issue | 2022-10-12 | | Date of Implementation | 2023-05-01 | | Older Standard (superseded by this standard) | GB/T 712-2011 | | Drafting Organization | Anshan Iron and Steel Co., Ltd., Metallurgical Industry Information Standard Research Institute, Xinyu Iron and Steel Co., Ltd., Hunan Valin Xiangtan Iron and Steel Co., Ltd., Jiangyin Xingcheng Special Steel Co., Ltd., Hebei Puyang Iron and Steel Co., Ltd., Nanjing Iron and Steel Co., Ltd., Benxi Iron and Steel Co., Ltd. Co., Ltd., Zhongke Xiwang Special Steel Co., Ltd., Guangxi Liuzhou Iron and Steel Group Co., Ltd., Laiwu Branch of Shandong Iron and Steel Co., Ltd., Qingdao Steel Research Nanoco Detection and Protection Technology Co., Ltd., Shougang Group Co., Ltd., China Classification Society, Guangdong Shaogang Songshan Co., Ltd. | | Administrative Organization | National Steel Standardization Technical Committee (SAC/TC 183) | | Proposing organization | China Iron and Steel Association | | Issuing agency(ies) | State Administration for Market Regulation, National Standardization Management Committee | | Standard ID | GB 712-2011 (GB712-2011) | | Description (Translated English) | [GB/T 712-2011] Ship and ocean engineering structural steel | | Sector / Industry | National Standard | | Classification of Chinese Standard | H46 | | Classification of International Standard | 77.140.50 | | Word Count Estimation | 17,166 | | Date of Issue | 2011-06-16 | | Date of Implementation | 2012-02-01 | | Older Standard (superseded by this standard) | GB 712-2000 | | Quoted Standard | GB/T 20066; GB/T 20123; GB/T 20124; GB/T 20125; YB/T 081; GB/T 222; GB/T 223.5; GB/T 223.9; GB/T 223.12; GB/T 223.14; GB/T 223.16; GB/T 223.19; GB/T 223.23; GB/T 223.25; GB/T 223.26; GB/T 223.37; GB/T 223.40; GB/T 223.62; GB/T 223.63; GB/T 223.67; GB/T 223.69; GB/T 228.1; GB/T 229; GB/T 247; GB/T 709; GB/T 2101; GB/T 2970; GB/T 2975; GB/T 4336; GB/T 5313; GB/T 17505 | | Drafting Organization | Angang Steel Company Limited | | Administrative Organization | National Steel Standardization Technical Committee | | Regulation (derived from) | Announcement of Newly Approved National Standards No. 9 of 2011 | | Proposing organization | China Iron and Steel Association | | Issuing agency(ies) | Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China; Standardization Administration of China | | Summary | This Chinese standard specifies the ship and marine engineering classification and structural steel grades, order contents, size, shape, weight and tolerances, requirements, inspection and testing, packaging, marking and quality certification. This standard applies to manufacture offshore, coastal and river trade area sailing ships, fishing vessels and marine engineering structures with a thickness of not more than 150mm of steel, the thickness is not greater than 25. 4mm and thickness of the strip and the clipboard or diameter of not more than 50mm of steel (hereinafter referred to as steel). | | Standard ID | GB 712-2000 (GB712-2000) | | Description (Translated English) | Hull structural steel | | Sector / Industry | National Standard | | Classification of Chinese Standard | H46 | | Classification of International Standard | 77.140.50 | | Word Count Estimation | 10,186 | | Date of Issue | 2000/4/11 | | Date of Implementation | 2000/11/1 | | Older Standard (superseded by this standard) | GB 712-1988 | | Quoted Standard | GB/T 222-1984; GB/T 223.3-1988; GB/T 223.4-1988; GB/T 223.11-1991; GB/T 223.14-2000; GB/T 223.16-1991; GB/T 223.17-1989; GB/T 223.18-1994; GB/T 223.19-1989; GB/T 223.23-1994; GB/T 223.24-1994; GB/T 223.26-1989; GB/T 223.27-1994; GB/T 223.36-1994; GB/T 223.37-1989; GB/T 223.40-1985; GB/T 223.54-1987; GB/T 223.58-1987; GB/T 223.59-1987; GB 223.60-1987; GB/T 223.61-1988; GB/T 223.62-1988; GB/T 223.63-1988; GB/T 223.64-1988; GB/T 223.68-1997; GB/T 223.69-1997; GB/T 223.71-1997; GB/T 223.72-1991; GB/T 223.74-1997; GB/T 223.76-1994; GB/T 228-1987; GB/T 229-1994; GB/T 232-1999; GB/T 247-1997; GB/T 709-1988; GB/T 2101-1989 | | Adopted Standard | IASS, MOD | | Drafting Organization | Metallurgical Information Standards Acedemy | | Administrative Organization | National Steel Standardization Technical Committee | | Regulation (derived from) | Announcement of Newly Approved National Standards 2011 No. 9 | | Proposing organization | State Bureau of Metallurgical Industry | | Issuing agency(ies) | State Quality and Technical Supervision | | Summary | This Standard specifies structural steel hull size, shape, technical requirements, test methods, inspection rules, packaging, marking and quality certificates. This Standard is applicable to manufacturing offshore, general strength steel and high-strength steel in coastal and river trade area with the ship hull structure, including the thickness of not more than 100mm of steel and thickness or diameter of not more than 50mm of steel. Hull structural steel (ingot, billet, sheet) are |
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