Translated English of Chinese Standard: GB/T3078-2008 www.chinesestandard.net Sales@ChineseStandard.net ICS 77.140.20 H 40 National Standard of the People s Republic of China GB Replacing GB/T 3078-1994 Quality Structural Steel Cold Drawn Bars Issued on: May 13, 2008 Implemented on: November 1, 2008 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China; Standardization Administration Committee. www.chinesestandard.net Page 1 of 17
Table of s Foreword... 3 1 Scope... 4 2 Normative references... 4 3 Classification... 8 4 Ordering information... 8 5 Dimension, shape, and allowable deviation... 9 6 Technical requirements... 9 7 Test methods... 15 8 Inspection rules... 16 9 Packing, marking, and quality certificate... 17 www.chinesestandard.net Page 2 of 17
Foreword This Standard replaces GB/T 3078-1994 "Technical Requirements for Quality Structural Steel Cold Drawn Bars". Compared with GB/T 3078-1994, the main changes in this Standard are as follows: The standard name was changed from "Technical Requirements for Quality Structural Steel Cold Drawn Bars" into "Quality Structural Steel Cold Drawn Bars"; DELETE non-cutting processing steels in the classification; ADD the "ordering information"; DELETE specification of the chemical composition of steels for cold upsetting; ADD specification of "smelting process"; ADD specification of the cold drawn-ground delivery condition; ADJUST the hardness values of 38CrSi and 38CrMoAlA delivered at cold drawn condition; DELETE specification of the mechanical properties of steels that are delivered at annealed condition and are used for cold upsetting; ADD specification of the sample surface after upset forging; DELETE the specification that "the total decarburized layer depth at one side of the ground bars may not be larger than 1.0%D"; DELETE specification of the surface quality of non-cutting process steels. This Standard was proposed by China Iron & Steel Association. This Standard shall be under the jurisdiction of the National Technical Committee on Iron and Steel of Standardization Administration of China. Drafting organizations of this Standard: Chongqing Donghua Special Steel Co., Ltd., and Metallurgical Information and Standardization Institute. Main drafters of this Standard: Li Qingyan, Liu Baoshi, Dai Qiang, and Luan Yan. The previous editions replaced by this Standard are as follows: GB 3078-1982, and GB/T 3078-1994. www.chinesestandard.net Page 3 of 17
Quality Structural Steel Cold Drawn Bars 1 Scope This Standard specifies the classification, ordering information, dimensions, shape and allowable deviation, technical requirements, test methods, inspection rules, packing, marking, and quality certificate of structural steel cold drawn and ground bars. This Standard is applicable to the quality carbon structural steel and alloy structural steel (round steel, square steel, and hexagonal steel) cold drawn steel bars. 2 Normative references The provisions in following documents become the provisions of this Standard through reference in this Standard. For dated references, the subsequent amendments (excluding corrigendum) or revisions do not apply to this Standard, however, parties who reach an agreement based on this Standard are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document 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 Diantipyrylmethane Phosphomolybdate Gravimetric Method for the Determination of Phosphorus GB/T 223.4 Alloyed Steel - Determination of Manganese - Potentiometric or Visual Titration Method GB/T 223.5 Steel and Iron - Determination of Acid-soluble Silicon and Total Silicon - Reduced Molybdosilicate Spectrophotometric Method GB/T 223.8 Methods for Chemical Analysis of Iron, Steel and Alloy - The Sodium Fluoride Separation - EDTA Titration Method for the Determination of Aluminium GB/T 223.9 Methods for Chemical Analysis of Iron, Steel and Alloy - The Chrom Azurol S Photometric Method for the Determination of Aluminium GB/T 223.11 Methods for Chemical Analysis of Iron, Steel and Alloy - The www.chinesestandard.net Page 4 of 17
Ammonium Persulfate Oxidation Volumetric Method for the Determination of Chromium 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 GB/T 223.13 Methods for Chemical Analysis of Iron, Steel and Alloy - The Ammonium Ferrous Sulfate Titration Method for the Determination of Vanadium 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 GB/T 223.16 Methods for Chemical Analysis of Iron, Steel and Alloy - The Chromotropic Acid Photometric Method for the Determination of Titanium GB/T 223.17 Methods for Chemical Analysis of Iron, Steel and Alloy - The Diantipyrylmethane Photometric Method for the Determination of Titanium GB/T 223.18 Methods for Chemical Analysis of Iron, Steel and Alloy - The Sodium Thiosulfate Separation Iodimetric Method for the Determination of Copper GB/T 223.19 Methods for Chemical Analysis of Iron, Steel and Alloy; The Neocuproine-chloroform Extraction Photometric Method for the Determination of Copper GB/T 223.23 Iron Steel and Alloy - Determination of Nickel - The Dimethylglyoxime Spectrophotometric Method GB/T 223.24 Methods for Chemical Analysis of Iron, Steel and Alloy - The Extraction Seperation - The Dimethylglyoxime Spectrophotometric Method for the Determination of Nickel GB/T 223.25 Methods for Chemical Analysis of Iron, Steel and Alloy - The Dimethylglyoxime Gravimetric Method for the Determination of Nickel GB/T 223.26 Iron Steel and Alloy - Determination of Molybdenum - The Thiocyanate Spectrophotometric Method GB/T 223.43 Methods for Chemical Analysis of Iron, Steel and Alloy - Determination of Tungsten GB/T 223.49 Methods for Chemical Analysis of Iron, Steel and Alloy - Extraction Separation-Chlorophosphonazo ma Spectrophotometric Method for the Determination of the Total Rare Earth www.chinesestandard.net Page 5 of 17
GB/T 223.54 Methods for Chemical Analysis of Iron, Steel and Alloy - The Flame Atomic Absorption Spectrophotometric Method for the Determination of Nickel GB/T 223.58 Methods for Chemical Analysis of Iron, Steel and Alloy - The Sodium Arsenite-sodium Nitrite Titrimetric Method for the Determination of Manganese GB/T 223.59 Methods for Chemical Analysis of Iron, Steel and Alloy - The Reduced Molybdoantimonyl Phosphoric Acid Photometric Method for the Determination of Phosphorus GB/T 223.60 Methods for Chemical Analysis of Iron, Steel and Alloy - The Perchloric Acid Dehydration Gravimetric Method for the Determination of Silicon GB/T 223.61 Methods for Chemical Analysis of Iron, Steel and Alloy - The Ammonium Phosphomolybdate Volumetric Method for the Determination of Phosphorus GB/T 223.62 Methods for Chemical Analysis of Iron, Steel and Alloy - The Butyl Acetate Extraction Photometric Method for the Determination of Phosphorus GB/T 223.63 Methods for Chemical Analysis of Iron, Steel and Alloy - The Sodium (potassium) periodate Photometric Method for the Determination of Manganese GB/T 223.64 Methods for Chemical Analysis of Iron, Steel and Alloy - The Flame Atomic Absorption Spectrometric Method for the Determination of Manganese GB/T 223.66 Methods for Chemical Analysis of Iron, Steel and Alloy - The Thiocyanate-chlorpromazine Hydrochloride-chloroform Extraction Photometric Method for the Determination of Tungsten GB/T 223.67 Iron Steel and Alloy - Determination of Sulfur - Methylene Blue Spectrophotometric Method 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 GB/T 223.69 Iron Steel and Alloy - Determination of Carbon s - Gas-volumetric Method after Combustion in the Pipe Furnace GB/T 223.71 Methods for Chemical Analysis of Iron, Steel and Alloy - The www.chinesestandard.net Page 6 of 17
Gravimetric Method after Combustion in the Pipe Furnace for the Determination of Carbon GB/T 223.72 Iron Steel and Alloy - Determination of Sulfur - Gravimetric Method GB/T 223.75 Methods for Chemical Analysis of Iron, Steel and Alloy -The Methanol Distillation-curcumin Photometric Method for the Determination of Boron GB/T 223.76 Methods for Chemical Analysis of Iron, Steel and Alloy - The Flame Atomic Absorption Spectrometric Method for the Determination of Vanadium GB/T 224 Determination of Depth of Decarburization of Steel GB/T 225 Steel - Hardenability Test by End Quenching (Jominy Test) (GB/T 225-2006, ISO 642: 1999, IDT) GB/T 226 Etch Test for Macrostructure and Defect of Steels GB/T 228 Metallic Materials - Tensile Testing at Ambient Temperature (GB/T 228-2002, eqv ISO 6892: 1998) GB/T 229 Metallic Materials - Charpy Pendulum Impact Test Method (GB/T 229-2007, ISO 148-1: 2006, MOD) GB/T 231.1 Metallic Materials - Brinell Hardness Test - Part 1: Test Method (GB/T 231.1-2002, eqv ISO 6506-1: 1999) GB/T 699 Quality Carbon Structural Steels GB/T 905-1994 Dimension, Shape, Weight and Tolerance for Cold-drawn Round, Square and Hexagonal Steels GB/T 1031 Surface Roughness Parameters and their Values GB/T 1814 Inspection Method for Steel Work Fractures GB/T 1979 Standard Diagrams for Macrostructure and Defect of Structural Steels GB/T 2101 General Requirement of Acceptance Packaging, Marking and Certification for Section Steel GB/T 2975 Steel and Steel Products - Location and Preparation of Test Pieces for Mechanical Testing (GB/T 2975-1998, eqv ISO 377: 1997) GB/T 3077 Alloy Structure Steels www.chinesestandard.net Page 7 of 17
GB/T 3207-1988 Bright Steel GB/T 4162 Forged and Rolled Steel Bars - Method for Ultrasonic Inspection GB/T 6394 Metal - Methods for Estimating the Average Grain Size GB/T 7736 Ultrasonic Inspecting Method for Macro-structure and Imperfection of Steel GB/T 10561 Determination of of Nonmetallic Inclusions in Steel - Micrographic Method Using Standards Diagrams (GB/T 10561-2005, ISO 4967: 1998, IDT) GB/T 13298 Metal - Inspection Method of Microstructure GB/T 13299 Steel - Determination of Microstructure GB/T 17505 Steel and Steel Products - General Technical Delivery Requirements (GB/T 17505-1998, eqv ISO 404: 1992) 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 Infrared Absorption Method after Combustion in an Induction Furnace (Routine Method) (GB/T 20123-2006, ISO 15350: 2000, IDT) YB/T 5293 Metallic Materials - Forging Test 3 Classification Steels in accordance with the application and processing purposes are classified into: a) Steel for pressure processing UP, Steel for thermal pressure processing Steel for cold upsetting steel for hot upset forging UHP, UCF, UHF; b) Steel for cutting processing UC. The application and processing purposes of steels shall be indicated in the contract. 4 Ordering information www.chinesestandard.net Page 8 of 17
Steels shall be delivered at the cold drawn, cold drawn and ground, or cold drawn and heat treated (annealed, bright annealed, normalized, high temperature tempered, normalized-then-tempered) conditions. Based on the agreement of both the supplier and the purchaser, and the indication in the contract, the steels may also be delivered at other conditions. The delivery condition of steels shall be indicated in the contract, if not, the steels shall be supplied at cold drawn condition. 6.4 Hardness 6.4.1 The hardness values of such steels delivered at the cold drawn, cold drawn and ground, annealed, bright annealed, high temperature tempered, or normalized-then-tempered shall comply with specifications in Table 1. As required by the purchaser, the hardness values of those of which the grade is not listed in Table 1 shall be specified by the supplier and the purchaser through negotiation. The hardness value of steels delivered at normalized condition shall be specified by the supplier and the purchaser through agreement. 6.4.2 For the steels that are delivered at cold drawn condition and are used for thermal pressure processing, the Brinell hardness values of 50Mn2, 45CrVA, 35CrMnSiA, 42CrMo, and 35CrMoVA shall comply with specifications in Table 1; the Brinell hardness values of 38CrSi and 38CrMoAlA shall not be larger than 285HBW; and the Brinell hardness values of the steels of other grades and delivery conditions shall not be larger than 269HBW. 6.4.3 Steels with sectional dimension less than 5mm shall not be carried out with hardness test or be specified by both parties through negotiation. 6.5 Mechanical properties As required by the purchaser, and indicated in the contract, the steels may be carried out with mechanical property tests. And the mechanical properties at the delivery condition shall comply with specifications in Table 2. For the grades that are not listed in Table 2, prepare samples with heat treated blank to determine mechanical properties. The quality carbon structural steels shall comply with specifications in GB/T 699, and the alloy structural steels shall comply with specifications in GB/T 3077. Table 1 Hardness at delivery condition Hardness at delivery condition /HBW, no larger than /HBW, no larger than Cold Annealed, bright Cold Annealed, bright No. Grade drawn, cold annealed, high temperature No. Grade drawn, cold annealed, high temperature drawn tempered, or drawn tempered, or and normalized-then-te and normalized-then-te ground mpered ground mpered www.chinesestandard.net Page 10 of 17
a It shall be indicated in the contract when Group 1 is required, otherwise, it shall be in accordance with the specification of Group 2. Note: D is the nominal diameter of steels. 6.9 Surface quality 6.9.1 The steel surface shall be clean and smooth without cracks, folds, scars, inclusions, tension fractures, and oxide scales; the surface of the heat treated cold drawn steels is allowed to have oxidation tint. 6.9.2 The surface of steels used for cutting processing is allowed to have pockmarks, scratches, pulling marks, black spots, concave face, cleaning bias, lubricant trace of which the depth does not exceed the nominal dimension tolerance, counted from the actual dimension, as well as individual small hair cracks in depth of one half of the tolerance. 6.9.3 The surface of steels for thermal pressure processing and steels for cold (hot) upset forging is allowed to have individual scratches, pulling marks, black spots, concave face, pockmarks, or cleaning bias of which the depth does not exceed the nominal dimension tolerance, counted from the actual dimension. As required by the purchaser, the above-mentioned defects may not exceed one half of the tolerance. 6.9.4 For the steels delivered at ground condition, their surface quality shall comply with specifications in GB/T 3207. 6.9.5 For the steels straightened with diagonal rolls, their surface may have thread-like roll marks. 6.9.6 The surface quality of the cold drawn square steel and hexagonal steel shall comply with specifications of steels for cutting processing. 6.10 Special requirements As required by the purchaser, upon agreement of the supplier and the purchaser, it can supply steels for the following special requirements. And the acceptance criterion shall be agreed by the supplier and the purchaser through negotiation. a) REDUCE scope of chemical compositions; b) Impact absorption energy at the delivery condition of steels; c) SPECIFY the upper and lower limits for the mechanical properties; d) Laminated fracture; e) Microstructure; www.chinesestandard.net Page 14 of 17
14 Dimension One by one On entire steel Caliper, micrometer 15 Surface One by one On entire steel Visual inspection 16 Roughness 1 Any steel GB/T 1031 Note: When batching steels of the mother-furnace, the sampling quantity, sampling position, and test method are same as the electric arc furnace steels. 8 Inspection rules 8.1 Inspection and acceptance 8.1.1 The inspection and acceptance of exit-factory steels shall be carried out by the quality technical supervision department of the supplier. 8.1.2 The supplier must ensure that the delivered steels comply with specifications in this Standard or the contract. If necessary, the purchaser is entitled to carry out inspection and acceptance for any inspection item specified in this Standard or in the contract. 8.2 Batching rules Steels shall be inspected and accepted in batches. And each batch shall be consisted of steels of the same-grade, same-furnace number, same-processing method, same-dimension, same-delivery condition, and same-heat treatment furnace number. For the steels by electroslag remelting, under the condition that the process is stable and the requirements of this Standard are guaranteed, steels are allowed to be delivered by batching according to the smelting mother-furnace number of consumable electrode. However, steels containing aluminium shall be batched only according to the electroslag furnace. 8.3 Sampling quantity and sampling position 8.3.1 Sampling quantity and sampling position of each batch of steels shall comply with specifications in Table 5. 8.3.2 When the electroslag steels are batched according to the smelting mother-furnace number, and the chemical compositions of each electroslag furnace are qualified, report the chemical compositions of any one electroslag ingot, to represent the chemical compositions of the whole mother-furnace (except the steels containing aluminium). And the sampling quantity and sampling position for other items shall comply with specifications in Table 5. 8.4 Re-inspection and determination rules 8.4.1 The re-inspection and determination rules of steels shall comply with specifications in GB/T 17505. www.chinesestandard.net Page 16 of 17
8.4.2 If the supplier can ensure that the steels are qualified, for the inspection results on mechanical properties, macrostructure, and nonmetallic inclusions of steels or steel billets of the same furnace number, it is allowed to replace inspection results of steels with billets, and replace the inspection results of small ones with large ones. 9 Packing, marking, and quality certificate The packing, marking, and quality certificate of steels shall comply with specifications in GB/T 2101. END www.chinesestandard.net Page 17 of 17