GB/T 34474-2025 (GB/T 34474.1-2017) PDF EnglishUS$265.00 · In stock · Download in 9 seconds
GB/T 34474.1-2017: Determination of Banded Structure of Steel - Part 1: Micrographic Method Using Standards Diagrams Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Valid GB/T 34474.1: Historical versions
Similar standardsGB/T 34474.1-2017: Determination of Banded Structure of Steel - Part 1: Micrographic Method Using Standards Diagrams---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT34474.1-2017 NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 77.040.99 H 24 Determination of Banded Structure of Steel - Part 1. Micrographic Method Using Standards Diagrams Issued on. OCTOBER 14, 2017 Implemented on. JULY 01, 2018 Issued by. General Administration of Quality Supervision, Inspection and Quarantine; Standardization Administration of PRC. Table of ContentsForeword... 3 Introduction... 4 1 Scope... 5 2 Normative References... 5 3 Terms and Definitions... 5 4 Overview and Application... 6 5 Sampling... 7 6 Preparation of Sample... 10 7 Evaluation Methods... 10 7.1 Observation method... 10 7.2 Comparison method... 10 7.3 Standard grading diagram... 10 8 Test Report... 12 Appendix A (Normative) Standard Grading Diagram... 13ForewordGB/T 34474 Determination of Banded Structure of Steel is supposed to be divided into several parts. This Part is Part 1 of GB/T 34474. This Part was drafted as per the rules specified in GB/T 1.1-2009. This Part was proposed by China Iron and Steel Industry Association. This Part shall be under the jurisdiction of National Technical Committee for Standardization of Steel (SAC/TC 183). Drafting organizations of this Part. Fushun Special Steel Co., Ltd.; China Metallurgical Information and Standardization Research Institute; Daye Special Steel Co., Ltd.; Shougang Corporation; Institute of Metal Research, Chinese Academy of Sciences; and Tianjin Iron and Steel Group Co., Ltd. Chief drafting staffs of this Part. Cheng Lijie, Luan Yan, Gu Qiang, Ju Xinhua, Gai Xiuying, Lu Bihong, and Zhang Long.IntroductionThis Part of GB/T34474 is based on the geometric distribution of ferrite bands of hypoeutectoid steel, and does not strictly stipulate the composition of the Class II structure banding. This Part is used to determine the banded structure of ferrite and pearlite in near- equilibrium state of hypoeutectoid steel, and also to evaluate the banded structure of ferrite and other non-equilibrium structures. Determination of Banded Structure of Steel – Part 1. Micrographic Method Using Standards Diagrams1 ScopeThis Part of GB/T 34474 stipulates the method of evaluation of the hypoeutectoid steel banded structure (including ferrite band and the Class II structure banding) by the comparative method. This Part is applicable to the evaluation of the banded structure of hypoeutectoid steel after plastic deformation, but not to the evaluation of the banded structure of carbide band in hypereutectoid steel.2 Normative ReferencesThe following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this document. GB/T 13298 Inspection Methods of Microstructure for Metals GB/T 30067 Standard Terminology Relating to Metallography3 Terms and DefinitionsFor the purpose of this document, the terms and definitions given in GB/T 30067 and the following apply. 3.1 Banded structure Alternating zone of microstructure that is eventually formed by the deformation and elongation of the micro-segregation zone, and parallel to the processing direction, during the plastic processing of steel. 3.3 Continuous banding In a field of view, the same type of structure band appears, only grain boundaries are separated between the grains, and no other type of structure exists.4 Overview and Application4.1 This Part describes the degree of clustering of the banded structure based on the structure and morphology. 4.2 The segregation that occurs during solidification of steel forms a regular arrangement during subsequent deformation. 4.3 The micro-segregation zone formed by solidified selective crystallization is the root cause of the distribution of the banded structure. The micro-segregation zone elongates in the subsequent deformation process to form a layered structure parallel to the deformation direction. 4.4 Banded structure shall affect the homogeneity in each direction of mechanical properties. 4.5 The results obtained by the inspection may be used for product inspection according to the technical agreement reached between the supplier and the purchaser; or to compare different manufacturing processes or process changes; or to provide data for structure-performance-application research. 4.8 Appendix A gives the grading atlas of the five series A~E. The level of each series of diagrams ranges from 0 to 5; and these levels raise with the increase the following factors, such as the number of ferrite bands, the degree of penetration through the field of view, continuity and width. See 7.3 for the specific boundaries.5 Sampling5.1 In general, the sample shall be taken on the product in the delivery state; and the inspection area of the sample is about 200mm2 (20mm×10mm). Sampling method and quantity are specified according to product standards or technical conditions. 5.2 If the product standard does not specify, the sampling method is as follows.6 Preparation of Sample6.1 The inspection status of the sample shall be in accordance with the provision of product standard or agreement. When not specified, it is recommended to inspect in delivery state.7 Evaluation Methods7.1 Observation method The following methods may be selected for inspection under the microscope. 7.2 Comparison method 7.2.1 When evaluating the banded structure in the steel, the level of the banded structure shall be determined according to the following factors, such as the number of ferrite bands, and the degree of the ferrite band through the field of view, continuity, and the width of the ferrite band. When grading, the most serious field of view on the inspection surface shall be selected for comparison and grading. 7.3 Standard grading diagram 7.3.1 The grading diagram of banded structure is composed of white and black two types of structures; white is ferrite, black is Class II structure, see Appendix A. 7.3.2 The grading diagram of banded structure is divided into five series from A to E according to carbon content. 7.3.3 The level of each series of diagrams is from level 0 to level 5; it is gradually raised according to the increase of the following factors, such as the number of ferrite bands, the degree of penetration through the field of view, continuity and width. Table 1 gives a detailed description of the structural characteristics of each level. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. |
