標(biāo)準(zhǔn)編號:	GB/T 8731-2008
中文名稱:	易切削結(jié)構(gòu)鋼
英文名稱:	Free-cutting structural steel
中標(biāo)分類:	H40    鋼鐵產(chǎn)品綜合
行業(yè)分類:	GB    國家標(biāo)準(zhǔn)
ICS分類:	77.140.01 77.140.01    鋼鐵產(chǎn)品綜合 77.140.01
發(fā)布機(jī)構(gòu):	國家質(zhì)量監(jiān)督檢驗(yàn)檢疫總局 中國國家標(biāo)準(zhǔn)化管理委員會
發(fā)布日期:	11-Sep-08
實(shí)施日期:	2009-5-1
標(biāo)準(zhǔn)狀態(tài):	valid
替代舊標(biāo)準(zhǔn):	GB/T 8731-1988 易切削結(jié)構(gòu)鋼技術(shù)條件
翻譯語言:	英文
文件格式:	PDF
中文字符數(shù):	12000 字
翻譯價(jià)格(元):	240.0
交付時間:	付款后 1 個工作日

1 Scope This standard specifies the scope, terms and definitions, ordering information, dimensions, shape, weight and tolerances, technical requirements, test methods, inspection rules, packing, marking and quality certificate of free-cutting structural steels. This standard is applicable to such steels as bar steels, wire rods, steel wires, steel plates and steel strips used for mechanical machining and their chemical compositions are also applicable to ingots and billets as well as their products. 2 Normative References The following normative documents contain provisions which, through reference in this text, constitute provisions of this national standard. For dated references, subsequent amendments to (excluding amending error in the text), or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of the normative document is applicable. For undated references, the latest edition of the normative document referred to 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 Content GB/T 223.11 Methods for Chemical Analysis of Iron, Steel and Alloy--The Ammonium Persulfate Oxidation Volumetric Method for the Determination of Chromium Content 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 223.19 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 223.29 Methods for Chemical Analysis of Iron, Steel and Alloy-The Xylenol Orange Photometric Method for Determination of Lead Content after Carrier Precipitation GB/T 223.50 Methods for Chemical Analysis of Iron, Steel and Alloy-The Phenylfuorone-CTMAB Direct Photometric Method for the Determination of Tin Content 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 Content 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 Content 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 223.61 Methods for Chemical Analysis of Iron, Steel and Alloy; The Ammonium Phosphomolybdate Volumetric Method for the Determination of Phosphorus Content 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 223.64 Methods for Chemical Analysis of Iron, Steel and Alloy; The Flame Atomic Absorption Spectrometric 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 223.68 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 223.69 Iron Steel and Alloy-Determination of Carbon Contents - Gas-volumetric Method after Combustion in the Pipe Furnace GB/T 223.71 Methods for Chemical Analysis of Iron, Steel and Alloy; The Gravimetric Method after Combustion in the Pipe Furnace for the Determination of Carbon Content GB/T 223.72 Iron Steel and Alloy-Determination of Sulfur Content-Gravimetric Method GB/T 223.74 Methods for Chemical Analysis of Iron, Steel and Alloy - The Combustion Gravimetric/Gas-volumetric Method for the Determination of Combined Carbon Content GB/T 223.77 Methods for Chemical Analysis of Iron, Steel and Alloy The Flame Atomic Absorption Spectrometric Method for the Determination of Calcium Content GB/T 224 Determination of Depth of Decarburization of Steel 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 247 General Rule of Acceptance, Package, Mark and Certification for Steel Plates (Sheets) and Strips GB/T 342 Dimension Shape Mass and Tolerance for Cold-drawn Round Square and Hexagonal Steel Wires GB/T 702 Hot-rolled Steel Bars – Dimensions, Shape, Weight and Tolerances GB/T 708 Dimension Shape Weight and Tolerance for Cold-rolled Steel Plates and Sheets GB/T 709 Dimension Shape Weight and Tolerances for Hot-rolled Steel Plates and Sheets GB/T 905 Dimension, Shape, Weight and Tolerance for Cold-drawn Round, Square and Hexagonal Steels GB/T 908 Forged Bars - Dimensions Shape Weight and Tolerances 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 2103 General Provisions for Checking, Packing, Marking and Quality Certification of Steel Wire 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 3207 Bright Steel GB/T 4336 Standard Test Method for Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low-alloy Steel (Routine Method) GB/T 10561 Steel Determination of Content of Nonmetallic Inclusions Micrographic Method Using Standards Diagrams GB/T 14981 Dimensions, Shape, Mass and Tolerances for Hot-rolled Wire Rods GB/T 15711 Steel Products-Method for Ecth Test of Tower Sample (GB/T 15711-1995, neq ISO 3673: 1976) 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 Content Infrared Absorption Method after Combustion in an Induction Furnace (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 following term and definition is applicable to this standard. 3.1 Free-cutting structural steel The structural steel of favorable machining performance by adding higher content of sulfur, lead, calcium and other free-cutting elements. 4 Classification Steels shall be classified into the following two classes according to the different application and processing methods. The application and processing method for steel bars shall be noted in the contract and the unnoted one shall be supplied as steels for machining. a) Steels for press working UP b) Steel for machining UC

Contents Foreword I Introduction III 1 Scope 2 Normative References 3 Terms and Definitions 4 Classification 5 Ordering Information 6 Dimension, Shape, Weight and Tolerance 7 Technical Requirements 8 Test Methods 9 Inspection Rules 10 Packing, Marking and Quality Certificate Appendix A (Informative) Reference Values for Mechanical Properties of Bar Steels and Wire Rods Made from Free-cutting Structural Steel Appendix B (Informative) Comparison Table of Designations in this Standard with Foreign Designations