HG/T 5060-2016Anticorrosive coatings for liquefied natural gas (LNG) storage tanks (English PDF)

5.4 Operation methods

5.4.1 Operation methods for coating performances

5.4.1.1 State in container

Open the container and stir with a spatula or stirring rod, allowing there to be sediments at the bottom of the container. If it is easy to mix evenly after stirring, it is rated as "Uniform without hard lumps after stirring". The main agent and curing agent of two-component coatings shall be inspected separately.

5.4.1.2 Non-volatile matter content

According to the provisions of GB/T 1725-2007, the main agent and curing agent of the two-component coating are mixed for inspection. The baking temperature is 105 °C±2 °C, the baking time is 2 hours, and the sample is about 2 g.

5.4.1.3 Applicable period

Pre-adjust the temperature of each component of the coating to 23 °C±2 °C, and mix evenly according to the proportion specified by the product (the middle value is taken when the proportion of the diluent is a range); take out 300 mL and put it into a 500 mL well-sealed iron can, place the can under the condition of 23 °C±2 °C; after the agreed time, inspect the state in the container and the coating appearance according to the requirements of 5.4.1.1 and 5.4.1.5. If the test results meet the requirements of 5.4.1.1 and 5.4.1.5, and there is no obstacle to the application of the coating during the panel-making process, it is rated as "Pass".

5.4.1.4 Drying time

Carry out the test according to the regulations of GB/T 1728-1979, in which surface dry test is carried out according to method B, hard dry test of putty is carried out according to method C, and hard dry tests of other coatings (including dried type) are carried out according to method A.

5.4.1.5 Coating appearance

The test panel is observed visually under scattered sunlight. If the coating is uniform and free of defects such as sagging, floating, pinholes, cracking, and peeling, it is rated as "Normal".

5.4.1.6 Bending test

The test is carried out according to the provisions of GB/T 6742-2007.

5.4.1.7 Flexibility

The test is carried out according to the provisions of GB/T 1748-1979.

5.4.1.8 Impact resistance

The test is carried out according to the provisions of GB/T l732-l993.

5.4.1.9 Density

The test is carried out according to the provisions of GB/T 6750-2007. The components of the product (except the diluent) are mixed according to the proportion specified by the manufacturer and then tested.

5.4.1.10 Fineness

The test is carried out according to the provisions of GB/T 1724-1979. The two-component coatings shall be inspected immediately after the main agent and curing agent are mixed.

5.4.1.11 Fluorine content in the base material

The test shall be carried out according to the provisions of Appendix A of HG/T 3792-2014.

5.4.1.12 Silicon-oxygen bond content in the base material

The test shall be carried out according to the provisions of Appendix A of HG/T 4755-2014.

5.4.1.13 Metal zinc content in non-volatile matter

The test shall be carried out according to the provisions of 5.7 in HG/T 3668-2009.

5.4.2 Operation methods for coating system performances

5.4.2.1 General provisions

Unless otherwise specified, the reagents used are all chemically pure and above, the water used is third-grade water in accordance with the provisions of GB/T 6682, and the test solution is adjusted to the test temperature before the test.

5.4.2.2 Coating appearance

5.4.2.7 Chloride ion permeability resistance

The test shall be carried out according to Appendix C.2 of JTJ 275-2000.

5.4.2.8 Humidity and heat cycle resistance

The test shall be carried out according to the regulations of JG/T 25-1999, a total of 10 cycles (a cycle consists of soaking in water at 23 °C±2 °C for 18 hours, freezing at - 20 °C±2 °C for 3 hours, and baking at 50 °C±2 °C for 3 hours). After the cycles are complete, observe visually under scattered sunlight. If 2 of the 3 test panels of Class A products do not show any coating defects such as blistering, cracking, peeling, dusting, obvious discoloring, and obvious dulling, it is rated as "no abnormality"; If 2 of the 3 test panels of Class B products do not show any coating defects such as rusting, blistering, cracking, peeling, dusting, obvious discoloring, and obvious dulling, it is rated as "no abnormality". If any of the above coating defects occurs, it shall be described according to GB/T 1766.

5.4.2.9 Moisture and heat resistance

The test shall be carried out according to the provisions of GB/T 1740-2007. If blistering, rusting, peeling, or other coating defect occurs, it shall be described according to GB/T 1766.

5.4.2.10 Salt spray resistance

The test shall be carried out according to the provisions of GB/T 1771-2007 (the test panel is not scribed). If blistering, rusting, peeling, or other coating defect occurs, it shall be described according to GB/T 1766.

5.4.2.11 Resistance to artificial weathering

The test shall be carried out according to the provisions of Cycle A in GB/T 1865-2009.

The evaluation of the results shall be carried out according to GB/T 1766.

6.1 Inspection classification

6.1.1 Product inspection is divided into factory inspection and type inspection.

6.1.2 The factory inspection items include the state in the container, non-volatile matter content, drying time, applicable period, density, and coating appearance.

6.1.3 Type inspection items include all technical requirements listed in this standard.

Under normal production conditions, heat and humidity resistance and salt spray resistance are tested every 3 years, resistance to artificial weathering is tested every 5 […]