What does Copper class 1a and Copper class 4b mean for metalworking fluid?

What does Copper class 1a and Copper class 4b mean for metalworking fluid?

In the labeling of Solano Industries Aqualub METALWORKING FLUIDS (coolants / metalworking fluids), the designations "Copper class 1a" and "Copper class 4b" typically refer to the results of copper corrosion tests according to ASTM D130 or a similar standard. 

This test determines how the fluid interacts with copper and copper alloy surfaces when they are in prolonged contact with oil or emulsion at elevated temperatures.

How classification works:

• The power strip is placed in the liquid and kept at a high temperature for a certain period of time (e.g., 3 hours at 100 °C).
• Then its surface is compared with the color standard of the copper strips.
• The result is recorded as Class (Grade) and subclass (a, b, c).
   

Example:
•    Copper class 1a = very high copper protection, the liquid does not corrode copper parts, suitable for sensitive copper alloys.
•    Copper class 4b = poor protection against copper corrosion, the liquid causes significant damage to the copper surface. Such liquids are not used in places where there are many copper parts (e.g., heat exchangers, brass components).
 

Solano Industries indicates 'Copper class' data, which helps understand how friendly or harmful the metalworking fluid is to copper and brass components in equipment and processing processes.