ASTM D4627 Iron Chip Corrosion for Water – Dilutable Metalworking Fluids
Cast iron chips are placed on a filter paper in a petri dish containing a fluid and allowed to stand for 20 to 24 hours at room temperature. Dilutions by weight % as follows are tested (0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 7 and 10%). The weakest concentration which results is no rust stain on the filter paper is defined as the 'breakpoint'.