GB/T 3488.4-2022 English PDF (GBT3488.4-2022)

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GB/T 3488.4-2022: Hardmetals - Metallographic determination of microstructure - Part 4: Characterisation of porosity, carbon defects and eta-phase content
GB/T 3488.4-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.160
CCS H 16
GB/T 3488.4-2022 / ISO 4499-4:2016
Hardmetals – Metallographic Determination of
Microstructure – Part 4: Characterization of Porosity,
Carbon Defects and Eta-Phase Content
(ISO 4499-4:2016, IDT)
ISSUED ON: OCTOBER 12, 2022
IMPLEMENTED ON: OCTOBER 12, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 4
1 Scope ... 6
2 Normative References ... 6
3 Terms and Definitions ... 6
4 Symbols and Units ... 7
5 Principle ... 7
6 Apparatus ... 7
7 Calibration of Measurement Apparatus ... 8
8 Preparation of Test Samples ... 8
9 Procedure ... 9
10 Uncertainty of Measurement ... 14
11 Test Report ... 14
Bibliography ... 16
Foreword
This Document was drafted as per the rules specified in GB/T 1.1-2020 Directives for
Standardization – Part 1: Rules for the Structure and Drafting of Standardizing Documents.
This Document is Part 4 of GB/T 3488 Hardmetals – Metallographic Determination of
Microstructure. GB/T 3488 consists of the following parts:
--- Part 1: Photomicrographs and Description;
--- Part 2: Measurement of WC Grain Size;
--- Part 3: Measurement of Microstructural Features in Ti (C, N) and WC/Cubic Carbide
Based Hardmetals;
--- Part 4: Characterization of porosity, Carbon Defects and Eta-Phase Content.
This Document equivalently adopts ISO 4499-4:2016 Hardmetals – Metallographic
Determination of Microstructure – Part 4: Characterization of Porosity, Carbon Defects and
Eta-Phase Content.
Please note some contents of this Document may involve patents. The issuing agency of this
Document shall not assume the responsibility to identify these patents.
This Document was proposed by China Nonferrous Metals Industry Association.
This Document shall be under the jurisdiction of National Technical Committee on Nonferrous
Metals of Standardization Administration of China (SAC/TC 243).
Drafting organizations of this Document: Xiamen Golden Egret Special Alloy Co., Ltd.;
Zhuzhou Cemented Carbide Group Co., Ltd.; Shenzhen Zhucheng Science and Technology Co.,
Ltd.; Nanchang Cemented Carbide Limited liability Company; Chongyi Zhangyuan Tungsten
Co., Ltd.; China United Test and Evaluation (Qingdao) Co., Ltd.; Guobiao (Beijing) Testing and
Certification Co., Ltd.; State Tungsten and Rare Earth Product Quality Inspection Center; and
Center for Industrial Analysis and Testing, Guangdong Academy of Sciences.
Chief drafting staffs of this Document: Zou Jianping, Fan Zhirui, Zhang Shubin, Lin Xiaoxuan,
Luo Haihui, Liang Hong, Zhang Yue, Zhou Yonggui, Huang Shuai, Zhang Fang, Xu Guozhuan,
Zhong Zhiqiang, Cui Wenming, Wang Weiwei, Liu Shufeng, Zhang Limin, Li Yajun, Yu
Yinhong, Wu Chaoqun, and Ma Wenhua.
Hardmetals – Metallographic Determination of
Microstructure – Part 4: Characterization of Porosity,
Carbon Defects and Eta-Phase Content
1 Scope
This Document specifies methods for the metallographic determination of the presence, type,
and distribution of porosity, carbon defects and eta-phase in hardmetals.
2 Normative References
The provisions in following documents become the essential provisions of this Document
through reference in 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) is applicable to this Document.
GB/T 3488.2-2018 Hardmetals - Metallographic determination of microstructure - Part 2:
Measurement of WC grain size (ISO 4499-2:2008, IDT)
3 Terms and Definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Carbon defects
Macroscopic precipitates of carbon (graphite) which can be in the form of large angular rosettes
or small flakes.
3.2 Eta-phase; η-phase
Cubic carbide based on M6C or M12C structure where M is a mixture of Co and W usually in
equal proportions; and which can be present as large (up to 100μm diameter) rosettes or small
micrometer-sized particles.
large eta-phase rosettes. When the eta-phase is present as smaller particles (see Figure 6), it is
recommended to use a 5 % Murakami’s solution for 20 min followed by washing the sample
with water. In both cases, the surface should be dried carefully with acetone or alcohol without
wiping.
9 Procedure
9.1 General
If the porosity or uncombined carbon is not uniform over the area of the test piece section being
examined, the locations on the section to which the evaluation refers shall be identified, for
example, as top, bottom, edge, rim (case), core, etc.
It should to be noted that the figures given in this Clause are only representing approximately
1/7 of the field of view in the microscope.
9.2 Determination of porosity
Pore size is defined as the maximum dimension of the pore in the section. Special reference
shall be made to the presence of cracks or slits.
9.2.1 Pores up to 10μm shall be assessed by scanning the surface of the test-piece section at a
magnification of either ×100 or ×200. An area fully representative of the test-piece section shall
be examined and compared with the range of photomicrographs shown in Figure 1 or Figure 2,
according to the chosen magnification. The porosity level shall be reported by reference to the
appropriate photomicrograph and designated as A02, A04, A06 or A08. If the level of A-type
pores is less than 50 % of that shown in Figure 1 (A02) or Figure 2 (A02), it shall be designated
as A00.
9.2.2 Pores within the range 10μm to 25μm shall be assessed by scanning the surface of the
test-piece section at a magnification of ×100. An area fully representative of the test-piece
section shall be examined and shall be compared with the range of photomicrographs shown in
Figure 3. The porosity level shall be reported by reference to the appropriate photomicrograph
and designated as B02, B04, B06 or B08.
If the number of B-pores appears to be less than or equal to that represented by B02, the number
of B-pores in the representative area (≥0.25 cm2) shall be counted. This number shall be divided
by the area examined to obtain the number of B-pores/cm2.
If this number is less than 70 pores/cm2, it shall be designated as B00 - #, where # is the number
of B-pores/cm2 so obtained. If the number is greater than or equal to 70 pores/cm2, it shall be
designated as B02.
9.2.3 If it is necessary to inspect for pores larger than 25μm, they shall be examined at a suitable
magnification up to ×100 and shall be counted and reported as the number of pores per unit