GB/T 4956-2003Non-magnetic coatings on magnetic substrates -- Measurement of coating thickness -- Magnetic method (English PDF)

Foreword

This Standard equivalently adopted ISO 2178:1982 Non-Magnetic Coatings on Magnetic

Substrates – Measurement of Coating Thickness – Magnetic Method (English Version).

This Standard replaced GB/T 4956-1985 Non-Magnetic Coatings on Magnetic Substrates -

Measurement of Coating Thickness - Magnetic Method.

This Standard made the following editorial modifications according to ISO 2178:1982:

a) Use "this Standard" to replace "this International Standard";

b) Cancel the Foreword of the international standard;

c) For ease of use, quote the national standard using the international standard;

d) Add the normative references.

This Standard was proposed by China Machinery Industry Federation.

This Standard shall be under the jurisdiction of National Technical Committee on Metallic and

Non-Metallic Coating of Standardization Administration of China.

Drafting organization of this Standard: Wuhan Research Institute of Materials Protection.

Participating drafting organization of this Standard: Zhejiang Yueqing Xinfeng Enterprise Co.,

Ltd.

Chief drafting staffs of this Standard: Yu Hui, Zhong Lichang, Feng Yongchun, Jia Jianxin,

Zheng Xiulin.

The historical edition replaced by this Standard is as follows:

--- GB/T 4956-1985.

Non-Magnetic Coatings on Magnetic Substrates –

Measurement of Coating Thickness – Magnetic Method

1 Scope

This Standard specifies the method of using coating thickness instruments of the magnetic type

for nondestructive measurements of the thickness of non-magnetic coatings (including vitreous

and porcelain enamel coatings) on magnetic basis metals.

The method is applicable only for measurements on reasonably flat specimens. In the case of

nickel coatings on non-magnetic substrates, the preferred method is that specified in GB/T

13744.

2 Normative References

The provisions in following documents become the provisions of this Standard through

reference in this Standard. For dated references, the subsequent amendments (excluding

corrigendum) or revisions do not apply to this Standard, however, parties who reach an

agreement based on this Standard are encouraged to study if the latest versions of these

documents are applicable. For undated references, the latest edition of the referenced document

applies.

GB/T 12334 Metallic and other inorganic coatings - Definitions and conventions

concerning the measurement of thickness (idt ISO 2064)

GB/T 13744 Measurement of coating thickness for electrodeposited nickel coatings on

magnetic and non - Magnetic substrates (eqv ISO 2361)

3 Principle

Coating thickness instruments of the magnetic type measure either the magnetic attraction

between a permanent magnet and the basis metal, as influenced by the presence of the coating,

or the reluctance of a magnetic flux path passing through the coating and the basis metal.

Coated standards consist of coatings of known, uniform thickness permanently bonded to a

basis metal.

6 Procedure