This standard is drafted according to rules given in GB/T 1.1-2009.
This standard supersedes "High-carbon Chromium Bearing Steel" (GB/T 18254-2002).
There have been some significant changes in this standard over GB/T 18254-2002 in the following technical aspects:
- The varieties of "steel pipes" are cancelled (see 1, 4.1.1.5, 5.1.3, 5.3.1.9, 5.3.1.10, 5.11.3, 5.12.4 of 2002 edition);
- The chapter - "Classification and Code" is added (see Chapter 3);
- "End use" and "surface condition" are added in the chapter - "Order Contents" (see Chapter 4 of this standard, and Chapter 3 of 2002 edition);
- Steel is classified into three quality grades (quality steel, high-grade fine steel and special-grade fine steel) according to the metallurgical quality (see Tables 1, 2, 5, 9, 10, 14, 15 and 16 of this standard, and 4.1.1, 4.1.1.3, 4.2.1, Table 3, Table 6, Table 7, 5.8, Table 8 and Table 9 of 2002 edition);
- The upper limits of delivery length for hot-rolled round steel and forged round steel are modified (see 5.1.2.1 of this standard, and 4.1.2.1 of 2002 edition);
- The "coil weight" of wire rod is modified (see 5.3 of this standard, and 4.1.2.2 of 2002 edition);
- The deflection index of hot-rolled round steel is tightened (see Table 3 of this standard, and Table 2 of 2002 edition);
- The designation GCr4 and its relevant technical requirements are cancelled (see Tables 3, 5 and 12 of 2002 edition);
- The requirement -"Ni+Cu≤0.50%" is cancelled (see Table 3 of 2002 edition);
- The designation G8Cr15 and its relevant technical requirements are added (see Table 4, Table 8, 6.8 and Table 21);
- The nickel content, phosphorus content, sulphur content and oxygen content indexes are tightened (see Tables 4 and 5 of this standard, and Table 3 of 2002 edition);
- The assessment indexes of aluminum, titanium, calcium, stannum, arsenic, stibium and lead are added (see Table 5 of this standard, and 5.1.2 of 2002 edition);
- The hardness of soft-annealed steel is modified (see Table 8 of this standard, and Table 5 of 2002 edition);
- The inspection items and grading diagram of "center segregation" are added (Table 9 and Grade 4 diagram in Appendix A of this standard, and Table 6 of 2002 edition);
- The inspection item-"bluing fracture" of special-grade fine steel is added (see 6.7.2 and Appendix B);
- The grading diagram of nonmetallic inclusion is modified, and the assessment indexes of single spherical particle (DS) and titanium nitride are added (see 6.8 of this standard, grading diagrams given in GB/T 10561, and 5.7 and Grade 4 diagram in Appendix A of 2002 edition);
- The decarburized layer indexes of steels are tightened (see 6.9 of this standard, and 5.11 of 2002 edition);
- The requirements of "microstructure" and "carbide network" for assessment of annealed steel for hot press working purpose are added (see 6.10 and 6.11 of this standard, and 5.9.2 and 5.10.1 of 2002 edition);
- The section -"special requirements" is added (see 6.14);
- The requirement -"the special-grade fine steels shall be subject to ultrasonic testing for surface quality piece by piece" is added in the chapter - "Test Methods" (see 7.12);
- The grading diagram with a amplification factor of 1,000× is added for microstructure (see Grade 5 diagram in Appendix A of this standard, and Grade 6 diagram in Appendix A of 2002 edition);
- Grade 2.5 spheroidized annealed network diagram is added (see Grade 6 diagram in Appendix A of this standard, and Grade 7 diagram of 2002 edition);
- The grading diagrams for hot-rolled (forged) and soft-annealed carbide network are added (see Grade 7 diagram in Appendix A);
- The test method for bluing fracture is added (see Appendix B);
- The sampling diagrams for microstructure, carbide nonuniformity and micro cavity are added (see Appendix C).
This standard is proposed by China Iron and Steel Association.
This standard is under the jurisdiction of National Technical Committee on Iron and Steel of Standardization Administration of China (SAC/TC 183).
Chief drafting organizations of this standard: Baosteel Special Metals Co., Ltd., Luoyang Bearing Research Institute Co., Ltd., Jiangyin Xingcheng Special Steel Co., Ltd., China Metallurgical Information and Standardization Institute, Central Iron & Steel Research Institute, Dongbei Special Steel Group Co., Ltd., Daye Special Steel Co., Ltd. and Xining Special Steel Co., Ltd.
Participating drafting organizations of this standard: Pangang Group Jiangyou Changcheng Special Steel Co., Ltd., Shijiazhuang Iron & Steel Co. Ltd., Suzhou Suxin Special Steel Co., Ltd., Jiangsu Lianfeng Equipment Co., Ltd., Zenith Steel Group Company Limited, Xingtai Iron and Steel Corp., Ltd. and Shougang Corporation.
Chief drafters of this standard: Zou Liandi, Lei Jianzhong, Luan Yan, Geng Ke, Yu Feng, Fu Yide, Zhen Juan, Xiao Aiping and Chen Lie.
Participating drafters of this standard: Hu Junhun, Chu Yanli, Xi Junliang, Xu Yifeng, Zhang Qian, Wan Wenhua, Miao Hongsheng, Meng Ruiying and Mei Yali.
The previous editions of the standard superseded by this standard are as follows:
- GB/T 18254-2000 and GB/T 18254-2002.
High-carbon Chromium Bearing Steel
高碳鉻軸承鋼
1 Scope
This standard specifies the classification and code, order contents, dimension, shape, technical requirements, test methods, inspection rules, and packaging, marking and certification of high-carbon chromium bearing steel.
This standard is applicable to the hot-rolled steel, forged round steel, round wire rod and cold-drawn round steel (rod or disc) (hereafter referred to as "steels") which are of high-carbon chromium bearing steel and used for manufacturing bearing ring and rolling element.
As agreed by the supplier and the purchaser, steels and steel billets of other varieties and specifications may also be supplied, and the specific requirements shall be noted in the contract.
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 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 - 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 223.23 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 223.29 Iron Steel and Alloy - Determination of Lead Content - Carrier Precipitation - Xylenol Orange Spectrophotometric Method
GB/T 223.31 Iron Steel and Alloy - Determination of Arsenic Content - Distillation - Molybdenum Blue Spectrophotometric Method
GB/T 223.47 Methods for Chemical Analysis of Iron, Steel and Alloy - The Carrier Precipitation - Molybdenum Blue Photometric Method for the Determination of Antimony Content
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 223.53 Methods for Chemical Analysis of Iron, Steel and Alloy - The Flame Atomic Absorption Spectrophotometric Method for the Determination of Copper 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 223.77 Methods for Chemical Analysis of Iron, Steel and Alloy - The Flame Atomic Absorption Spectrometric Method for the Determination of Calcium Content
GB/T 223.85 Steel and Iron - Determination of Sulfur Content - Infrared Absorption Method after Combustion in an Induction Furnace
GB/T 223.86 Steel and iron - Determination of Total Carbon Content - Infrared Absorption Method after Combustion in an Induction Furnace
GB/T 224-2008 Determination of Depth of Decarburization of Steel
GB/T 226 Test Method for Macrostructure and Defect of Steel by Etching
GB/T 231.1 Metallic Materials - Brinell Hardness Test - Part 1: Test Method
GB/T 702-2008 Hot-rolled Steel Bars – Dimensions, Shape, Weight and Tolerances
GB/T 905-1994 Dimension, Shape, Weight and Tolerance for Cold-drawn Round, Square and Hexagonal Steels
GB/T 908-2008 Forged Bars - Dimensions, Shape, Weight and Tolerances
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 4336 Standard Test Method for Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low-alloy Steel (Routine Method)
GB/T 10561-2005 Steel - Determination of Content of Nonmetallic Inclusions - 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 14981-2009 Dimensions, Shape, Mass and Tolerances for Hot-rolled Round Wire Rod
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 20125 Low-alloy Steel - Determination of Multi-element Contents - Inductively Coupled Plasma Atomic Emission Spectrometric Method
YB/T 5293 Metallic Materials-Forging Test
3 Classification and Code
3.1 According to metallurgical quality, steel is classified into:
a) Quality steel;
b) High-grade fine steel (letter "A" is added after the designation);
c) Special-grade fine steel (letter "E" is added after the designation).
3.2 According to casting technology, steel is classified into:
a) Moulded steel;
b) Continuously cast steel.
3.3 According to applied work method, steel is classified into:
a) Steel for pressure work (UP);
b) Steel for cut work (UC).
3.4 According to end use, steel is classified into:
a) Steel for ring (T);
b) Steel for rolling element (G).
4 Order Contents
The order contract under this standard shall include the following contents:
a) Product name (or brand name);
b) Designation;
c) Serial number of standard;
d) Dimension and accuracy;
e) Weight and/or quantity;
f) Casting method (according to continuous casting if it is not indicated);
g) Applied working method;
h) Metallurgical quality;
i) Delivery condition;
j) End use (according to ring if it is not indicated);
k) Surface condition (it shall be indicated if the products are required to be delivered at peeled, polished or lathed condition);
l) Items or indexes which shall be negotiated by the supplier and the purchaser and noted in the contract;
m) Other special requirements.
5 Dimension, Shape and Weight
5.1 Dimensions and their tolerances
5.1.1 Diameter of steels and its tolerance
The diameter of steels and its tolerance shall be in accordance with those specified in Table 1.
Table 1 Diameter of Steels and Its Tolerance
Steel type Metallurgical quality Diameter and its tolerance
Hot-rolled round steel Quality steel and high-grade fine steel Group 2 in Table 1 of GB/T 702-2008
Special-grade fine steel Group 1 in Table 1 of GB/T 702-2008
Forged round steel - Group 1 in GB/T 908-2008
Cold-drawn round steel - Grade h11 in GB/T 905-1994 a
Round wire rod Quality steel and high-grade fine steel Grade B accuracy in GB/T 14981-2009
Special-grade fine steel Grade C accuracy in GB/T 14981-2009
a As agreed by the supplier and the purchaser and being noted in the contract, products also may be delivered according to the requirements of other grades.
5.1.2 Length
5.1.2.1 The normal length of steels shall meet the following requirements:
a) The length of hot-rolled round steel is 3,000mm~8,000mm;
b) The length of forged round steel is 2,000mm~6,000mm;
c) The length of cold-drawn round steel is 3,000mm~6,000mm.
5.1.2.2 Steels shall be delivered by uniform length within the specified length range, and the length difference between the longest and shortest steels in each bundle shall not be larger than 1,000mm.
5.1.2.3 As for the steels delivered according to fixed length or double length, their length tolerance shall not exceed mm.
5.2 Shape and its tolerance
5.2.1 Out-of-roundness
The out-of-roundness of steels shall be in accordance with those specified in Table 2.
Table 2 Out-of-roundness of Steels
Steel type Metallurgical quality Requirement for out-of-roundness
Hot-rolled round steel - Meeting the requirements of GB/T 702-2008
Forged round steel - Meeting the requirements of GB/T 908-2008
Cold-drawn round steel - Meeting the requirements of GB/T 905-1994
Round wire rod Quality steel and high-grade fine steel Meeting Grade B accuracy as stated in GB/T 14981-2009
Special-grade fine steel Meeting Grade C accuracy as stated in GB/T 14981-2009
5.2.2 Deflection
The deflection of steels shall be in accordance with those specified in Table 3.
Table 3 Deflection of Steels In: mm
Steel type Deflection, ≤
Deflection per meter Total deflection
Hot-rolled round steel 3.0 0.3%×Length of steel
Hot-rolled annealed round steel 3.0 0.3%×Length of steel
Forged round steel 5.0 0.5%×Length of steel
Cold-drawn round steel Diameter≤25 2.0 0.2%×Length of steel
Diameter>25 1.5 0.15%×Length of steel
As agreed by the supplier and the purchaser and being noted in the contract, products also may be delivered according to other requirements in the aspect of deflection of steels.
5.2.3 Torsion
Steels shall be free from any obvious torsion.
5.2.4 End shape
5.2.4.1 The ends of steels shall be sawed or cut regularly and shall be free from flash, burr and the oblique cutting and flattening that affect the application of steels.
5.2.4.2 Generally, the steels shall not be gas cut. On rare occasions (mainly when sampling), it is allowed to apply gas cutting at one end of no more than 6 steels in each batch.
5.2.4.3 One end of special-grade fine steel shall be chamfered. If quality steel and high-grade fine steel need to be chamfered, it shall be noted in the contract.
5.3 Weight
Steels shall be delivered according to the actual weight. The coil weight of round wire rod shall meet the requirements of GB/T 14981-2009.
Foreword I
1 Scope
2 Normative References
3 Classification and Code
4 Order Contents
5 Dimension, Shape and Weight
6 Technical Requirements
7 Test Methods
8 Inspection Rules
9 Packing, Marking and Certification
Appendix A (Normative) Standard Diagrams of High-carbon Chromium Bearing Steel
Appendix B (Normative) Inspection Method of Bluing Fracture
Appendix C (Normative) Sampling Diagrams for Microstructure, Carbide Nonuniformity and Micro Cavity
