GB/T 14999.1-2025 English PDFGB/T 14999.1: Historical versions
Basic dataStandard ID: GB/T 14999.1-2025 (GB/T14999.1-2025)Description (Translated English): Test method for superalloys - Part 1: Macro-structures Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: H40 Classification of International Standard: 77.140.99 Word Count Estimation: 35,335 Date of Issue: 2025-08-29 Date of Implementation: 2026-03-01 Older Standard (superseded by this standard): GB/T 14999.1-2012, GB/T 14999.2-2012, GB/T 14999.3-2012 Issuing agency(ies): State Administration for Market Regulation; Standardization Administration of China GB/T 14999.1-2025: Test method for superalloys - Part 1: Macro-structures---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/GBT14999.1-2025ICS 77.140.99 CCSH40 National Standards of the People's Republic of China Replace GB/T 14999.1-2012, GB/T 14999.2-2012, GB/T 14999.3-2012 High Temperature Alloy Inspection Methods Part 1.Low Magnification Structure Published on 2025-08-29 Implemented on 2026-03-01 State Administration for Market Regulation The State Administration for Standardization issued a statement. ForewordThis document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1.Structure and Drafting Rules of Standardization Documents". Drafting. This document is Part 1 of GB/T 14999, "Test Methods for High-Temperature Alloys". GB/T 14999 has the following parts published. ---Part 1.Low-magnification tissue; ---Part 2.High-resolution structures. This document replaces GB/T 14999.1-2012 "Test Methods for High Temperature Alloys - Part 1.Longitudinal Low Magnification Microstructure and Defects - Acid Immersion Inspection". Test methods for high-temperature alloys, GB/T 14999.2-2012 "Test methods for high-temperature alloys - Part 2.Acid etching inspection of transverse low-magnification microstructure and defects" and GB/T 14999.3-2012 "High-Temperature Alloys - Test Methods - Part 3.Examination of Longitudinal Fracture Surfaces of Bars". This document is based on GB/T 14999.1- This document primarily follows the.2012 standard, integrating the content of GB/T 14999.2-2012 and GB/T 14999.3-2012.This document is consistent with GB/T 14999.1-2012. In comparison, aside from structural adjustments and editorial changes, the main technical changes are as follows. a) Six terms have been changed. foreign inclusions, looseness, bubbles, cracks, delamination, and dark spots. The terms foreign metal inclusions, looseness, bubbles, and overheating have also been changed. The English equivalents for the seven terms stratification, carbide accumulation, point segregation, etc. (see Chapter 3,.2012 edition); b) The requirements for surface roughness of low-magnification test pieces have been added (see 4.1.5); c) Three recommended etchants, etching conditions, and methods have been added (see 4.2.1); d) Added requirements related to the assessment of transverse low-magnification microstructure and defects (see Appendix B); e) Added requirements related to longitudinal fracture assessment (see Appendix C). Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents. This document was proposed by the China Iron and Steel Association. This document is under the jurisdiction of the National Steel Standardization Technical Committee (SAC/TC183). This document was drafted by. Fushun Special Steel Co., Ltd., Beijing Steel Research Institute Gaona Technology Co., Ltd., and Metallurgical Industry Information Standards. Research Institute, Panzhihua Iron and Steel Group Jiangyou Great Wall Special Steel Co., Ltd., and Western Superconducting Materials Technology Co., Ltd. The main drafters of this document are. Gu Qiang, Yu Teng, Chen Huixia, Luan Yan, Wang Lin, Wang Hongxiao, Li Ke, Chen Qingxin, Yang Yujun, Yan Chengming, and Du Yujun. Zhu Hua. The document replaced by this document has been released in the following versions. ---GB/T 14999.1, first published in.1994, was incorporated into GB/T 14999.5-1994 "High Temperature" during its first revision in.2012. Chapter 1, "Longitudinal Low-Magnification Microstructure Rating Chart of High-Temperature Alloy Bars," in the book "Standard Rating Charts of Low-Magnification and High-Magnification Microstructures of Alloys," contains the content of this book. (GB/T 14999.5 was first published in.1994); ---GB/T 14999.2, first published in.1994, first revised in.2012; ---GB/T 14999.3, first published in.1994, was incorporated into GB/T 14999.5-1994 "High Temperature" during its first revision in.2012. The content of Chapter 2 "Longitudinal Fracture Rating Diagram of High Temperature Alloy Bars" in "Standard Rating Diagram of Low-Magnification and High-Magnification Microstructure of Alloys".introductionGB/T 14999, "Test Methods for High-Temperature Alloys," is a standard for the metallographic examination of high-temperature alloys, aiming to guide the testing of wrought and cast high-temperature alloys. Inspection of low-magnification and high-magnification microstructures and defects in high-temperature alloys and powder metallurgy high-temperature alloys. GB/T 14999 is proposed to consist of three parts. constitute. ---Part 1.Low-magnification tissue; ---Part 2.High-Magnification Structure; ---Part 3.Determination of casting grain size, primary dendrite spacing and microporosity. This document provides low-magnification images of the microstructure and fracture surface of the following deformed high-temperature alloy materials. ---Macroscopic average grain size, coarse grain bands, fine grain bands, and primary carbide banding microstructure standard rating of melt-tested materials, forgings (rolled billets) or parts. picture; ---Typical images of longitudinal microstructure and defects from ingots, melt-tested materials, forged (rolled) billets or parts, magnified at low magnification; ---Typical images of common defects and inhomogeneities in the transverse low-magnification structure of ingots, melt-tested materials, forgings (rolled billets) or parts; ---Images showing the longitudinal fracture porosity and delamination rating of hot-rolled bars. This document presents a recommended testing method, applicable only to two-dimensional planar (section) longitudinal and transverse low-magnification microstructures and three-dimensional longitudinal fracture surfaces. Inspection cannot determine whether the low magnification or fracture structure and defects of the tested high-temperature alloy are acceptable or suitable for use. Areas where low-magnification tissue examination is questionable can be examined with high-magnification tissue, analyzed, and then comprehensively evaluated. High Temperature Alloy Inspection Methods Part 1.Low Magnification Structure 1.Scope This document describes common defects and inhomogeneities in the longitudinal and transverse low-magnification microstructure of wrought superalloys, as well as porosity and fracture surface defects in the longitudinal fracture surface. The types and characteristics of the layers, sample cutting and preparation, testing and evaluation, result presentation methods, test reports, etc. This document applies to the inspection of longitudinal and transverse low-magnification microstructure and defects in wrought high-temperature alloy ingots, melt-tested materials, forged (rolled) billets, or finished products. His products follow the same guidelines. This document also applies to the inspection of fracture porosity and delamination in deformed hot-rolled high-temperature alloy bars with a nominal diameter of not less than 16 mm. The fracture surface inspection of other types of bars shall be performed in accordance with the same procedure.2 Normative referencesThe contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included. For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies. This document. GB/T 6394 Method for Determination of Average Grain Size of Metals GB/T 30067 Metallographic Terminology 3.Terms and Definitions The terms and definitions defined in GB/T 30067 and the following terms and definitions apply to this document. 3.1 foreign slag inclusion Defects are caused by the mixing of alloy slag and foreign materials such as refractory materials during the smelting and casting process. 3.2 Defects caused by incomplete melting of alloy materials or mixing with foreign metals during the smelting and casting process. Note. The color of the acid-etched specimen differs from the matrix tissue, and it has no fixed shape. Some specimens have a clear boundary with the matrix tissue, while others have an unclear boundary. 3.3 residual shrinkage The defect is caused by insufficient cutting of the alloy ingot, resulting in some shrinkage cavities remaining on the billet. Note. Irregular voids or cracks appear in the center of the transverse alloy low-magnification acid-etched specimens; constricted tubular structures appear on the longitudinal specimens; on the longitudinal fracture surface, corresponding to the residual... Delamination occurs at the shrinkage cavity site. Severe porosity, inclusions (slag inclusions), and component segregation are often present on or near it. 3.4 loose porosity The defect is due to insufficient feeding of the final solidified alloy liquid in the center of the alloy ingot, resulting in a non-dense microstructure. Note. Dark black dots and fine pores appear in the center of the transverse specimen after low-magnification acid leaching of the alloy; the longitudinal fracture surface is layered and fibrous. At the filling end of the alloy ingot... The loose texture may be accompanied by the accumulation of gas and inclusions. 3.5 Bubble bubbles Pores are formed when gas cannot escape during the solidification process of an alloy. Note. In the transverse low-magnification specimens of the alloy ingot, bubbles appear as round pores, while in the longitudinal low-magnification specimens, they appear as spindle-shaped pores, and sometimes as silkworm-shaped grooves of varying lengths. Appearing at the bottom of electroslag ingots; appearing as clusters of irregular, short, "S"-shaped fine cracks on transverse low-magnification specimens of forged and rolled parts; observed at higher magnification, they are... Cracks without inclusions. 3.6 crack Striped metal separation is formed when metal breaks on or inside the surface of an alloy ingot, billet, or material due to various reasons. Note. The following are some common types of cracks. a) Due to improper control of the smelting and casting processes, the alloy ingot contains numerous inclusions and exhibits severe segregation. During hot working, these inclusions often become more prominent in these areas. Cracks may form. For example, a large number of chain-like inclusions and carbide segregation may accumulate at the crack site, usually accompanied by fine grain zones. b) Cracks caused by low hot working temperatures, especially in processes such as punching, reaming, molding, rolling, and forging. For example, transgranular or intergranular cracks. c) Excessive hot working temperature or prolonged heating and holding time can cause oxidation or localized melting at grain boundaries, leading to a sharp decrease in the alloy's plasticity and resulting in processing cracks. Texture. For example. network crack, central cross crack. d) Cracks caused by excessive deformation, uneven hammering, or excessively rapid deformation. Examples include. cross-shaped cracks, blooming cracks, localized cracks, and fissures. Heart-forging cracks. e) Cracks caused by excessively high furnace loading temperature, rapid heating or cooling rates leading to explosion, or localized overheating during grinding wheel cutting. Examples include. petal-shaped cracks. Textures, network-like aggregated cracks, etc. 3.7 overheating Defects are formed when an alloy is heated to excessively high temperatures, causing oxidation and localized melting at the grain boundaries. Note. Overheating is generally indicated by cracks and severe delamination on the surface low-magnification test piece. 3.8 Stratification The near-perfect appearance is caused by subsurface bubbles and severe porosity in the alloy ingot that were not welded together during rolling or forging, or by secondary shrinkage and foreign inclusions. Defects parallel to the surface of the billet or material. Note. On the inspection surface of the longitudinal fracture, there are longitudinal striations, but no metallic granular structure and the metallic luster has been lost; moreover, the continuity of the metal is disrupted. It is generally grayish-white, pale yellow, or brownish-black. The three most common types of layering are. a) Central delamination caused by secondary shrinkage cavities and foreign inclusions; b) Subcutaneous delamination caused by porosity and cold flow during the ingot injection process is irregularly distributed, but the defects always gradually extend from one side of the surface towards the center; c) Small delaminations caused by fine chain-like inclusions produced by secondary oxidation, located on the fracture surface of the material. 3.9 Carbide aggregation A type of interdendritic segregation. Note. In longitudinal low-magnification acid-etched specimens, dark bands distributed along the processing direction appear; in transverse low-magnification acid-etched specimens, areas slightly darker than the matrix appear, with a curved pattern. Or a cluster of short, black lines. 3.10 spot segregation Aggregation regions of carbides and/or second phases. Note. On transverse low-magnification acid-etched specimens, dark gray or black spots of varying sizes appear, which are more susceptible to corrosion than the substrate and tend to embed into it; on longitudinal low-magnification specimens, along the... The cracks are distributed along the direction of the work, appearing in strips, and can form fine cracks in severe cases. 3.11 Dark spots freckle Positive segregation is formed by aggregated elements of carbides, carbonitrides, Laves phase, μ phase, and other intermetallic compounds. Note. The dark areas are on the acid-etched test pieces. 3.12 white spots Negative segregation resulting from a reduction in carbides and carbide-forming or strengthening elements. Note. 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