Dynamic Water Washout Test

Dynamic Water Washout Test is a standard method (ASTM D1264) used to evaluate a grease’s resistance to water exposure. It is crucial in determining how well a lubricating grease can stay in place and maintain its performance when exposed to wet conditions, a common challenge in many industrial and outdoor environments.
Test Procedure:
In this test, a ball bearing packed with grease is mounted in a housing and rotated at a speed of 600 RPM while water is sprayed at it under controlled conditions :
• Test Temperatures : 38°C (100°F) and 79°C (175°F)
• Water Flow Rate: ~300 ml/min
• Test Duration: 1 hour approx.
The amount of grease washed out is measured to assess its resistance, offering a clear indication of the grease’s adhesion, durability and protective capability in wet environments.
Applications :
This test is particularly significant for greases used in outdoor industrial systems, heavy industries and construction as well as agricultural machinery, where application’s exposure to water is unavoidable.

pH level and cutting fluid performance
The pH level of the cutting fluid in machining operations affect metal protection and fluid stability .pH of any metalworking fluid is a key indicator of the fluid’s health. Typically, water-miscible cutting fluids are designed to maintain a slightly alkaline pH, between 8.5 and 9.5 (approx.), to effectively neutralize acidic contaminants and inhibit bacterial growth in accordance with ISO standards.

An optimal pH not only helps in maintaining fluid cleanliness but also contributes to corrosion protection especially on ferrous metals. Fluids with too low a pH may become acidic, corroding machine components and workpieces. Drop in pH levels is a major indicator that something is wrong with the emulsion health and is important to address the root cause.

On the contrary, excessively high pH can damage metal alloys and effect operator safety. Regular monitoring of pH and concentration is essential for maintaining fluid performance and extending tool and machine life.

The procedure involves use of standard cast iron chips, filter paper, cutting oil, and water for emulsion preparation, at room temperatures.

Test procedure:
• Place a filter paper inside a Petri dish
• Weigh approximately two grams of cast iron chips and add them to the Petri dish
• Pipette the coolant lubricant solution onto the chips until they are thoroughly soaked
• Tilt the chips into the Petri dish and start a timer for two hours
• After two hours, tilt the chips out of the Petri dish and remove the wet filter paper
• Rinse the filter paper with water and allow it to dry.
• Observe the filter paper for any signs of corrosion and grade the corrosion level accordingly

To combat corrosion, high-quality cutting fluids incorporate corrosion inhibitors such as boron compounds, amine soaps and synthetic additives in the formulation. This enables the cutting fluid to form a thin protective film on metal surfaces.