GB/T 30789.4-2015Paints and varnishes -- Evaluation of degradation of coatings -- Designation of quantity and size of defects, and of intensity of uniform changes in appearance -- Part 4: Assessment of degree of cracking (English PDF)

Foreword

GB/T 30789 Paints and varnishes - Evaluation of degradation of coatings -

Designation of quantity and size of defects, and of intensity of uniform changes

in appearance consists of the following parts.

- Part 1. General introduction and designation system;

- Part 2. Assessment of degree of blistering;

- Part 3. Assessment of degree of rusting;

- Part 4. Assessment of degree of cracking;

- Part 5. Assessment of degree of flaking;

- Part 6. Assessment of degree of chalking by tape method;

- Part 7. Assessment of degree of chalking by velvet method;

- Part 8. Assessment of degree of delamination and corrosion around a

scribe or other artificial defects;

- Part 9. Assessment of degree of filiform corrosion.

This Part is the fourth part of GB/T 30789.

This Part was drafted in accordance with the rules given in GB/T 1.1-2009.

This Part uses translation method and identically adopts ISO 4628-4.2003

Paints and varnishes - Evaluation of degradation of coatings - Designation of

quantity and size of defects, and of intensity of uniform changes in appearance

- Part 4. Assessment of degree of cracking.

This Part was proposed by China Petroleum and Chemical Industry Federation.

This Part shall be under the jurisdiction of National Technical Committee on

Paints and Pigments of Standardization Administration of China (SAC/TC 5).

The drafting organizations of this Part. CNOOC Changzhou Paint and

Chemicals Research Institute Co., Ltd., China Zhiqi (Shenzhen) Co., Ltd.,

Guangzhou Synthetic Material Research Institute Co., Ltd., AVIC Bermuda New

Material Technology Engineering Co., Ltd., Zhejiang Yutong New Material Co.,

Ltd., Dongguan Yian Technology Co., Ltd..

Main drafters of this Part. Zhang Ping, Cheng Hongqi, Wen Jing, Shi Hua, Yang

Yaliang, Tang Tiezhuang.

Paints and varnishes - Evaluation of degradation of

coatings - Designation of quantity and size of defects,

and of intensity of uniform changes in appearance -

Part 4. Assessment of degree of cracking

1 Scope

This Part of GB/T 30789 describes a method for assessing the degree of

cracking of coatings by comparison with pictorial standards, using the

designation system defined in GB/T 30789.1.

ISO 4628-1 defines the system used for designating the quantity and size of

defects and the intensity of changes in appearance of coatings and outlines the

general principles of the system. This system is intended to be used, in

particular, for defects caused by ageing and weathering, and for uniform

changes such as colour changes, for example yellowing

2 Normative references

The following referenced documents are indispensable for the application of

this document. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any

amendments) applies.

ISO 4628-1, Paints and varnishes - Evaluation of degradation of coatings -

Designation of quantity and size of defects, and of intensity of uniform

changes in appearance - Part 1. General introduction and designation

system

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.