[No.2/17] What the anti-corrosion performance can be determined and evaluated by of the rust preventive oil?
Last time, I have explained about what types are available in the rust preventive oil. I would like to explain this time about how the the rust preventive performances are confirmed by respective testing method on the basis of JIS specifications.
The quality of the rust preventive oil is defined in JIS K 2246 “Rust preventive oils”, and a lot of quality has been listed by the type of the rust preventive oil respectively. In that list, the testing method of “Humidity cabinet test” is focused as the confirmation method of rust preventive performance.
This testing method is that the steel sheet coated with the rust preventive oil is hung in the atmosphere of a lot of steam such as a steam bath, and then to check how long time it takes to get corroded on the steel sheet.
The testing results can be roughly seen as per the Table 1 for the lubricating oil type rust preventive oil and solvent cutback type rust preventive oil. You can find that there is considerable wide range depending on the applications from the kind of no corrosion even after one month to the type of simply not corroded for 8 days testing periods as maximum. To materialize this quality, it is important that how thick the rust preventive oil has been coated.
On the lubricating oil-type rust preventive oil, the film thickness is determined by the viscosity of the rust preventive oil. As a matter of course, the higher viscosity oil makes the thicker film.
On the other hand, the film thickness after drying is definitely specified, as the solvent cutback-type rust preventive oil contains the solvent evaporative after all.
It should be kept in mind that the steel sheet used for the test is polished with a polishing cloth or polishing paper. It means that the total volume of the rust preventive oil adhered on the polished surface is more than the time of the mirror surface before polished, as the surface becoming rough by the polishing.
Depending on the surface condition of the steel products to be actually prevented, it will be different by the coated thickness of oil film and film thickness, when compared with the figures in Table 1.
The several testing methods are also listed other than the “Humidity cabinet test” in JIS Specifications.
In this column, there is not enough space to explain in detail for JIS Specifications, it is recommended to see JIS Specifications themselves to get the full details. You can see the full text when searching the Japanese Industrial Standards Committee on their homepage. Please try to access for the better understanding.
○ JISC: Japanese Industrial Standards Committee (JIS search browse)
You can search the contents only when inputting the following JIS No. or the specification name, JIS K 2246 “Rust preventive oils”.