Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
GB/T 34560 consists of the following six parts under the general title Structural steels:
——Part 1: General technical delivery condition for hot-rolled products;
——Part 2: Technical delivery conditions for structural steels for general purposes;
——Part 3: Technical delivery conditions for fine grain structural steels;
——Part 4: Technical delivery conditions for high yield strength quenched and tempered structural steel plates;
——Part 5: Technical delivery condition for atmospheric corrosion resisting steels;
——Part 6: Technical delivery conditions for seismic-improved structural steels for building.
This part is Part 3 of GB/T 34560.
This part is drafted in accordance with the rules given in GB/T 1.1-2009.
This part has been redrafted and modified in relation to ISO 630-3: 2012 Structural steels - Part 3: Technical delivery conditions for fine grain structural steels.
Structural adjustments have been made with respect to ISO 630-3:2012, and a cross reference table for the clause numbers of this standard and those of ISO 630-3:2012 is listed in Annex B.
This part includes technical differences with respect to ISO 630-3:2012. The clauses and subclauses concerned are identified by a vertical single line (|) located in the blank on its external margin of the page. These technical differences and reasons are listed in Annex B.
For the convenience of use, the following editorial changes are made in this part:
——The bibliography is deleted;
——The informative Annex C is added.
This part was proposed by China Iron and Steel Association.
This part is under the jurisdiction of the National Technical Committee 183 on Iron and Steel of Standardization Administration of China (SAC/TC 183).
Structural steels - Part 3: Technical delivery conditions for fine grain structural steels
1 Scope
This part of GB/T 34560 specifies the terms and definitions, designation expression methods, order details, dimensions, shape, mass and tolerance, technical requirements, test methods, inspection rules, packaging, and marking and quality certificate of fine-grain structural steels in the normalized, normalized-rolled and thermomechanical-rolled delivery conditions.
This part is applicable to steel plates and strips, wide flats, sections and bars, which are intended for use in heavily loaded parts of welded or bolted structures.
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 (including any amendments) applies.
GB/T 222 Permissible tolerances for chemical composition of steel products
GB/T 223.3 Methods for chemical analysis of iron, steel and alloy - The diantipyryl methane phosphomolybdate gravimetric method for the determination of phosphorus content
GB/T 223.9 Iron, steel and alloy - Determination of aluminium content - Chrome azurol S photometric method
GB/T 223.11 Iron, steel and alloy - Determination of chromium content - Visual titration or potentiometric titration method (GB/T 223.11-2008, ISO 4937:1986, MOD)
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 223.17 Methods for chemical analysis of iron, steel and alloy - The diantipyrylmethane photometric method for the determination of titanium content
GB/T 223.18 Methods for chemical analysis of iron, steel and alloy - The sodium thiosulfate separation - Iodimetric 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 223.26 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 methods 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 223.60 Methods for chemical analysis of iron, steel and alloy - The perchloric acid dehydration gravimetric method for the determination of silicon 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 223.68 Methods for chemical analysis of iron, steel and alloy-The potassium iodate titration method after combustion in the pipe furnace for the determination of sulfur content
GB/T 223.76 Methods for chemical analysis of iron, steel and alloy - The flame atomic absorption spectrometric method for the determination of vanadium content
GB/T 223.78 Methods for chemical analysis of iron, steel and alloy - Curcumin spectrophotometric method for the determination of boron content (GB/T 223.78-2000, ISO 10153:1997, IDT)
GB/T 223.79 Iron and Steel - Determination of multi-element contents - X-ray fluorescence spectrometry (routine method)
GB/T 223.84 Steel, iron and alloy - Determination of titanium content - Diantipyrylmethane spectrophotometric method (GB/T 223.84-2009, ISO 10280:1991, IDT)
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room temperature (GB/T 228.1-2010, ISO 6892-1:2009, MOD)
GB/T 229 Metallic materials - Charpy pendulum impact test method (GB/T 229-2007, ISO 148-1:2006, MOD)
GB/T 247 General rule of package, mark and certification for steel plates (sheets) and strips
GB/T 2101 General requirement of acceptance, packaging, marking, and certification for section steel
GB/T 2975-2018 Steel and steel products - Location and preparation of samples and test pieces for mechanical testing (GB/T 2975-2018,
ISO 377:2017, MOD)
GB/T 4336 Carbon and low-alloy steel - Determination of multi-element contents - Spark discharge atomic emission spectrometric method (routine method)
GB/T 5313 Steel plates with through-thickness characteristics
GB/T 8170 Rules of rounding off for numerical values & 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 20066-2006; ISO 14284:1996, IDT)
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 20123-2006; ISO 15350:2000, IDT)
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 20124-2006, ISO 15351:1999, IDT)
GB/T 20125 Low-alloy steel - Determination of multi-element contents - Inductively coupled plasma atomic emission spectrometric method
GB/T 34560.1 Structural steels - Part 1: General technical delivery condition for hot-rolled products (GB/T 34560.1-2017; ISO 630-1: 2011, MOD)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 34560.1 apply.
4 Designation representation method
4.1 Steel designation is composed of four parts: Q (the Chinese phonetic alphabet representing the yield strength); the specified minimum upper yield strength; the delivery condition code; quality grade symbol (B, C, D, E and F).
Note 1: Where the delivery condition is as-rolled, the delivery condition code AR or WAR may be omitted; where the delivery condition is normalized or normalized-rolled, the delivery condition code is indicated by N.
Note 2: Q + the specified minimum upper yield strength value + delivery condition code is referred to as “steel grade” as a whole.
Example: Q355ND. where,
Q——the Chinese phonetic alphabet representing the yield strength;
355——the specified minimum upper yield strength, MPa;
N——the delivery condition of normalized or normalized-rolled;
D——the quality grade of Grade D.
4.2 Where the purchaser requires that the steel plate should be provided with through-thickness properties, a symbol representing the property grade in thickness direction (Z direction) shall be added after the above-mentioned designation, e.g. Q355NDZ25.
5 Order contents
5.1 Contracts or orders made based on this part shall cover the following items:
a) Serial No. of this part;
b) Product type;
c) Steel designation (steel grade + quality grade);
d) Dimensions, shape and tolerances (see Clause 6);
e) Delivery mass (or quantity);
f) All selected contents as required (see 5.2).
5.2 For the purpose of this part, the following contents may be selected for order through negotiation between the supplier and the purchaser as indicated in the contract. If not specified by the purchaser upon inquiry and order, products shall be suppled according to 5.1.
a) Carbon equivalent value and welding crack susceptibility index (Pcm) (see 7.1.2, Table 4);
b) Added alloying elements and their contents (see 7.1.4, Tables 1 and 3);
c) The lower limit of chemical composition upon supplying commercial billet (see 7.1.6);
d) Analysis of finished products (see 7.1.7);
e) Steelmaking process (see 7.2);
f) Temperature and sampling direction of the impact test (see Table 7);
g) Through-thickness properties of steels (see 7.1.5, 7.4.4 and 9.2.2);
h) Sampling position for impact specimens (see 8.3).
6 Dimensions, shape and mass
The dimensions, shape, mass and tolerances of the steel shall meet those specified in GB/T 34560.1.
7 Technical requirements
7.1 Designation and chemical composition of steel
7.1.1 The designation and chemical composition (determined by heat analysis) of normalized and normalized-rolled steel shall be in accordance with those specified in Table 1 and its carbon equivalent value shall be in accordance with those specified in Table 2.
7.1.2 The designation and chemical composition (determined by heat analysis) of thermomechanical processed steel shall be in accordance with those specified in Table 3 and its carbon equivalent value shall be in accordance with those specified in Table 4. Where the carbon content in thermomechanical processed steel is not greater than 0.12%, the welding crack susceptibility index (Pcm) may be adopted to replace the carbon equivalent value for assessing the weldability of steel; in case of no specific requirements, either of them can be used.
7.1.3 The carbon equivalent value (CEV) shall be calculated using Formula (1) based on the heat analysis components, while the welding crack susceptibility index (Pcm) shall be calculated using Formula (2) based on the composition determined by heat analysis:
CEV=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 (1)
Pcm=C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/15+V/10+5B (2)
7.1.4 The alloying elements other than those specified in Tables 1 and 3 may be added into the steel as agreed by the supplier and the purchaser. The alloying elements and their contents shall be indicated in the quality certificate.
7.1.5 If steel plates with through-thickness properties are required by the purchaser, their sulphur content shall meet the requirements of GB/T 5313.
7.1.6 When supplying commercial billets, in order to ensure that the mechanical property of steel meets the requirements of this part, the lower limit of the chemical composition of each element shall be subject to negotiation between the supplier and the purchaser.
7.1.7 The chemical composition analysis of finished steel products may be carried out upon the agreement between the supplier and the purchaser. The tolerance of the chemical composition of finished products shall meet the requirements of GB/T 222.
7.1.8 See Annex A for comparison of domestic and foreign designations.
7.2 Steelmaking process
The steels are generally fine grain steel manufactured from a converter or electric furnace and contain sufficient amounts of nitrogen-binding elements. If necessary, it can be refined outside the furnace. Special requirements (if any) shall be indicated in the contract.
7.3 Delivery condition
Steels are delivered in normalized, normalized-rolled or thermomechanical processed condition.
Note: The normalized condition includes normalized + tempered condition, and the thermomechanical processed (TMCP) condition includes thermomechanical processed (TMCP) + tempered condition.
7.4 Mechanical properties
7.4.1 The tensile properties of normalized and normalized-rolled steel shall meet those specified in Table 5.
7.4.2 The tensile properties of thermomechanical processed (TMCP) steel shall meet those specified in Table 6.
7.4.3 The Charpy (V-notch) impact test shall be carried out in accordance with GB/T 34560.1 and the test temperature and impact absorbed energy shall meet those specified in Table 7.
7.4.4 As required by the purchaser and indicated in the contract, where the through-thickness properties of the steel are required, the percentage reduction of area in thickness shall meet the requirements of GB/T 5313.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Designation representation method
5 Order contents
6 Dimensions, shape and mass
7 Technical requirements
8 Test methods
9 Inspection rules
10 Packaging, marking and quality certificate
Annex A (Informative) Structural changes of this part with reference to ISO 630-3:
Annex B (Informative) Technical differences between this part and ISO 630-3: 2012 and their causes
Annex C (Informative) Comparison of similar designations given in domestic and international standards
