Step 1:

Place the filter paper in the Petri dish. (The description differs slightly from the norm, where 70mm diameter filter paper is used, with a circle (pencil) of 40mm. We recommend 55 mm filter paper, without circle, because there are very inexpensive Petri dishes for this.)

Step 2:

Weigh approx. 2g chips directly into the Erlenmayer or the test tube (25-35 pieces) - do not touch the chips by hand before testing.

Step 3:

Pipette cooling lubricant solution onto the chips until they are thoroughly wetted.

Step 4:

Tip wet chips into the Petri dish. (The filter should become wet over the entire surface, but the chips should not be flooded with coolant - if necessary remove excess liquid.) Distribute chips as evenly as possible.

Step 5:

Start clock

Step 6:

After 2 hours, tilt the chips out of the Petri dish, remove the wet filter with tweezers, rinse the filter briefly with water and allow to dry. (Alternatively, immerse the wet filter briefly in acetone and allow to dry.)

Evaluation:

Compare the corrosion pattern with the original from the standard. The desired value is level 0 = no corrosion, 1 is still quite good, above this level is actually not tolerable. (There is also a reading scheme in the standard). Classification is possible to 1 level).

Comment on the procedure

The test is a bit rough, but very useful if you can't explain why parts or machines rust or when it comes to comparing KSS. The chips must, of course, be manufactured in accordance with the standards.

The standard distinguishes 4 degrees of corrosion according to the number and size of the spots, 0 means no corrosion 4 indicates serious deficiencies in corrosion protection. The standard should be obtained from Beuth-Verlag (https://www.beuth.de) to ensure that it is carried out and evaluated in accordance with the standards. This method can be used to check the condition of coolant lubricants on machines used for steel and grey cast iron machining or to protect machine beds made of grey cast iron against corrosion in good time.

Reasons for inadequate corrosion protection in water-mixed KSS:

• Faulty equipment of the KSS recipe - Manufacturer's error

• Use of too low concentrations

• Degradation of the KSS by germs

• Chloride concentrations too high due to salting from the preparation water

• .... Many other reasons we can help you with.

A typical question:

Comparison of the corrosion protection of two water-mixed cooling lubricants:

Prepare both cooling lubricants with the same preparation water. (Use your own process water for this.) Concentrations: 2% 3% 4% 5% 6%. Mix well before the test to obtain a uniform emulsion.

For each concentration level:

Weigh 2g chips into a 50 ml Erlenmeyer. Mark the Erlenmeyer with a felt pen e.g. A2%, A3%, A4% ...B2%, B3%, B4%...

Place one round filter in each Petri dish. Put the same inscription on the lid as on the Erlenmeyer flask. (2 samples are used for each concentration level in accordance with the standards.)

See above for other procedures.