Issued by the Ministry of Industry and Information Technology of the People's Republic of China
Contents
Foreword i
1 Scope 1
2 Normative references 1
3 Specimen cutting and display method 1
4 Classification and evaluation of macrostructure and defects in continuous casting billets 1
5 Standard diagrams 5
6 Rating method 6
7 Inspection report 6
Annex A (Normative) Standard diagrams for macrostructure and defects in continuous casting billets 7
Annex B (Informative) Schematic diagram of macrostructure and defects in continuous casting billets 30
Foreword
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.
This standard replaces YB/T 4002-1991 Standard diagrams for macrostructure and defects in continuous casting billets.
The following main changes have been made with respect to YB/T 4002-1991:
——The upper limit of continuous casting billet size has been expanded in terms of the side length from 90mm to 200mm to 90mm to 400mm;
——The relevant provisions and words of the original standard scope, classification and evaluation of defects have been revised accordingly;
——The "Foreword" has been added;
——The defects of white bright band, foreign metal inclusion, skull patch, slag inclusion and white spot have been added;
——Annex B “Schematic diagrams for macrostructure and defects in continuous casting billets” has been added.
This standard was proposed by China Iron and Steel Association.
This standard is under the jurisdiction of SAC/TC 183 National Technical Committee on Iron and Steel of Standardization Administration of China.
The previous edition of this standard is as follows:
——YB/T 4002-1991.
Standard diagrams for macrostructure and defects in continuous casting billets
1 Scope
This standard specifies the morphology characteristics, causes and evaluation principle of macrostructure and defects in continuous casting billets.
This standard is applicable to the evaluation of acid etched macrostructure and defects of billets of, such as, carbon steel and low alloy steel, produced by continuous casting process. The cross-sectional size of billet ranges from 90mm to 400mm in side length, and rectangular billet can also be used as a reference.
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 of the referenced document (including any amendments) applies.
GB/T 226 Test method for macrostructure and defect of steel by etching
3 Specimen cutting and display method
Specimen cutting and display method shall be in accordance with GB/T 226. Other specimen display method may also be used upon agreement between the supplier and the purchaser.
4 Classification and evaluation of macrostructure and defects in continuous casting billets
4.1 Central porosity
Morphology characteristics: Voids and dark spots concentrated in the center of the acid etched test piece.
Causes: Loose structure caused by volume shrinkage during solidification of billet and serious gas precipitation and inclusion accumulation in the center of billet due to final solidification.
Evaluation principle: According to Annex A, evaluate based on the number, size and density of dark spots and voids.
Foreword i 1 Scope 2 Normative references 3 Specimen cutting and display method 4 Classification and evaluation of macrostructure and defects in continuous casting billets 5 Standard diagrams 6 Rating method 7 Inspection report Annex A (Normative) Standard diagrams for macrostructure and defects in continuous casting billets Annex B (Informative) Schematic diagram of macrostructure and defects in continuous casting billets
ICS 77.040.99
H 24
Professional Standard of the People’s Republic of China
YB/T 4002-2013
Replaces YB/T 4002-1991
Standard diagrams for macrostructure and defects in continuous casting billets
连铸钢方坯低倍组织缺陷评级图
(English Translation)
Issue date: 2013-04-25 Implementation date: 2013-09-01
Issued by the Ministry of Industry and Information Technology of the People's Republic of China
Contents
Foreword i
1 Scope 1
2 Normative references 1
3 Specimen cutting and display method 1
4 Classification and evaluation of macrostructure and defects in continuous casting billets 1
5 Standard diagrams 5
6 Rating method 6
7 Inspection report 6
Annex A (Normative) Standard diagrams for macrostructure and defects in continuous casting billets 7
Annex B (Informative) Schematic diagram of macrostructure and defects in continuous casting billets 30
Foreword
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.
This standard replaces YB/T 4002-1991 Standard diagrams for macrostructure and defects in continuous casting billets.
The following main changes have been made with respect to YB/T 4002-1991:
——The upper limit of continuous casting billet size has been expanded in terms of the side length from 90mm to 200mm to 90mm to 400mm;
——The relevant provisions and words of the original standard scope, classification and evaluation of defects have been revised accordingly;
——The "Foreword" has been added;
——The defects of white bright band, foreign metal inclusion, skull patch, slag inclusion and white spot have been added;
——Annex B “Schematic diagrams for macrostructure and defects in continuous casting billets” has been added.
This standard was proposed by China Iron and Steel Association.
This standard is under the jurisdiction of SAC/TC 183 National Technical Committee on Iron and Steel of Standardization Administration of China.
The previous edition of this standard is as follows:
——YB/T 4002-1991.
Standard diagrams for macrostructure and defects in continuous casting billets
1 Scope
This standard specifies the morphology characteristics, causes and evaluation principle of macrostructure and defects in continuous casting billets.
This standard is applicable to the evaluation of acid etched macrostructure and defects of billets of, such as, carbon steel and low alloy steel, produced by continuous casting process. The cross-sectional size of billet ranges from 90mm to 400mm in side length, and rectangular billet can also be used as a reference.
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 of the referenced document (including any amendments) applies.
GB/T 226 Test method for macrostructure and defect of steel by etching
3 Specimen cutting and display method
Specimen cutting and display method shall be in accordance with GB/T 226. Other specimen display method may also be used upon agreement between the supplier and the purchaser.
4 Classification and evaluation of macrostructure and defects in continuous casting billets
4.1 Central porosity
Morphology characteristics: Voids and dark spots concentrated in the center of the acid etched test piece.
Causes: Loose structure caused by volume shrinkage during solidification of billet and serious gas precipitation and inclusion accumulation in the center of billet due to final solidification.
Evaluation principle: According to Annex A, evaluate based on the number, size and density of dark spots and voids.
Contents of YB/T 4002-2013
Foreword i
1 Scope
2 Normative references
3 Specimen cutting and display method
4 Classification and evaluation of macrostructure and defects in continuous casting billets
5 Standard diagrams
6 Rating method
7 Inspection report
Annex A (Normative) Standard diagrams for macrostructure and defects in continuous casting billets
Annex B (Informative) Schematic diagram of macrostructure and defects in continuous casting billets
