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GB/T 3488.4-2022Hardmetals - Metallographic determination of microstructure - Part 4: Characterisation of porosity, carbon defects and eta-phase content (English PDF)

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Issued by

SAMR; SAC

Level / Type

National · Recommended

Issue date

October 12, 2022

Implementation date

October 12, 2022

Scope

GB/T 3488.4-2022 (Hardmetals - Metallographic determination of microstructure - Part 4: Characterisation of porosity, carbon defects and eta-phase content) is available as an English-translated PDF.

GB/T 3488.4-2022 — This Document specifies methods for the metallographic determination of the presence, type, and distribution of porosity, carbon defects and eta-phase in hardmetals.

Document preview — GB/T 3488.4-2022

National Standard of the People's Republic of China

Issued by: SAMR; SAC

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 & Technology Co.,

Ltd.; Nanchang Cemented Carbide Limited liability Company; Chongyi Zhangyuan Tungsten

Co., Ltd.; China United Test & Evaluation (Qingdao) Co., Ltd.; Guobiao (Beijing) Testing &

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; eta-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 x100 or x200. 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 x100. 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 x100 and shall be counted and reported as the number of pores per unit

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — all pages — is available in the English PDF.

Referenced standards

Normative references

GB/T 3488.2-2018 · ISO 4499

Cited by

GB/T 46324-2025Cemented carbide products for ultra precision optical dies

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