This standard specifies the classification and code, order contents, dimensions, shape, weight and tolerances, technical requirements, test methods, inspection rules, packaging, marking and certification of alloy structure steels.
This standard is applicable to hot-rolled and forged alloy structure steel bars with nominal diameter or thickness not greater than 250mm. Based on the agreement of both supplier and purchaser, hot-rolled and forged alloy structure steel bars (hereinafter referred to as “steel bars”) whose nominal diameter or thickness is greater than 250mm may also be supplied.
The designations and chemical compositions specified in this standard are also applicable to steel ingots, steel billets and their products.
2 Normative References
The following documents for the application of this document are essential. Any dated reference, just dated edition applies to this document. For undated references, the latest edition (including any amendments) applies to this document.
GB/T 222 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 223.4 Alloyed Steel - Determination of Manganese Content - Potentiometric or Visual Titration Method
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 223.11 Iron Steel and Alloy - Determination of Chromium Content - Visual Titration or Potentiometric Titration Method
GB/T 223.13 Methods for Chemical Analysis of Iron, Steel and Alloy-The Ammonium Ferrous Sulfate Titration 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 223.18 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 223.43 Iron Steel and Alloy - Determination of Tungsten Content - Gravimetric Method and Spectrophotometric Method
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 Content
GB/T 223.59 Iron Steel and Alloy - Determination of Phosphorus Content - Bismuth Phosphomolybdate Blue Spectrophotometric Method and Antimony Phosphomolybdate Blue 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 223.67 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 223.75 Iron Steel and Alloy - Determination of Boron Content - Methanol Distillation-Curcumin Photometric Method
GB/T 224 Determination of Depth of Decarburization of Steels
GB/T 225 Steel-Hardenability Test by End Quenching (Jominy Test)
GB/T 226 Test Method for Macrostructure and Defect of Steel by Etching
GB/T 228.1 Metallic Materials - Tensile Testing - Part 1: Method of Test at Room Temperature
GB/T 229 Metallic Materials - Charpy Pendulum Impact Test Method
GB/T 231.1 Metallic Materials - Brinell Hardness Test C Part 1: Test Method
GB/T 702 Hot-rolled Steel Bars - Dimensions, Shape, Weight and Tolerances
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 2975 Steel and Steel Products - Location and Preparation of Test Pieces for Mechanical Testing
GB/T 4162 Forged and Rolled Steel Bars - Method for Ultrasonic Testing
GB/T 4336 Standard Test Method for Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low - Alloy Steel (Routine Method)
GB/T 6394 Metal-Methods for Estimating the Average Grain Size
GB/T 6402 Steel Forgings - Method for Ultrasonic Testing
GB/T 7736 Ultrasonic Inspecting Method for Macro-Structure and Imperfection of Steel
GB/T 8170-2008 Rules of Rounding Off for Numerical Values & Expression and Judgement of Limiting Values
GB/T 10561 Steel Determination of Content of Nonmetallic Inclusion Micrographic Method Using Standards Diagrams
GB/T 11261 Steel and Iron - Determination of Oxygen Content - The Pulse Heating Inert Gas Fusion-Infrared Absorption Method
GB/T 13298 Inspection Methods of Microstructure for Metals
GB/T 13299 Steel - Determination of Microstructure
GB/T 15711 Steel Products - Method for Ecth Test of Tower Sample
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
GB/T 21834 Medium and Low Alloy Steel - Determination of The Distribution of Multi-element Contents - Original Position Statistic Distribution Analysis Method
GB/T 28300 Surface Quality Classes for Hot-Rolled Bars and Rods Technical Delivery Conditions
YB/T 4306 Iron, Steel and Alloy - Determination of Nitrogen Content - Thermal Conductimetric Method after Fusion in a Current of Inert Gas
YB/T 5293 Metallic Materials - Forging Test
3 Classification and Code
3.1 According to the metallurgical quality, the steel bars are classified into three categories as follows:
a) Quality steel;
b) High-grade quality steel (designation followed by "A");
c) Special-grade quality steel (designation followed by "E").
3.2 According to the application and machining method, steel bars are classified into two categories as follows:
a) Steel for pressure processing UP;
1) Thermal pressure processing UHP;
2) Steel used for upsetting UF;
3) Blank for cold-drawing UCD;
b) Steel for cutting processing UC.
3.3 According to surface type, steel bars are classified into five categories as follows:
a) Pressure machine surface SPP;
b) Acid cleaning SA;
