CMRT CMRT Lubrication and Tribology 1 — Questions and Answers
Question 1: What does the term 'tribology' refer to in the context of maintenance?
- The study of friction, wear, and lubrication between interacting surfaces (Correct answer)
- The measurement of vibration in rotating equipment
- The analysis of corrosion in metal components
- The process of aligning rotating shafts
Correct answer: The study of friction, wear, and lubrication between interacting surfaces
Tribology is the science that studies friction, wear, and lubrication of interacting surfaces in relative motion.
Question 2: Which lubrication regime occurs when the lubricant film fully separates the two mating surfaces?
- Boundary lubrication
- Mixed lubrication
- Hydrodynamic (full-film) lubrication (Correct answer)
- Elasto-hydrodynamic lubrication
Correct answer: Hydrodynamic (full-film) lubrication
Hydrodynamic (full-film) lubrication occurs when the lubricant film is thick enough to completely separate the mating surfaces, minimizing metal-to-metal contact.
Question 3: What does the viscosity index (VI) of an oil indicate?
- The oil's resistance to oxidation over time
- How much the oil's viscosity changes with temperature (Correct answer)
- The oil's ability to prevent rust and corrosion
- The load-carrying capacity of the oil
Correct answer: How much the oil's viscosity changes with temperature
The viscosity index (VI) indicates how much an oil's viscosity changes with temperature; a higher VI means less viscosity change over a wide temperature range.
Question 4: Which type of grease thickener is most commonly used in industrial bearings due to its high temperature and water-resistance properties?
- Calcium soap
- Sodium soap
- Lithium soap (Correct answer)
- Aluminum complex soap
Correct answer: Lithium soap
Lithium soap is the most widely used grease thickener in industrial applications because it offers a good balance of high-temperature stability, water resistance, and mechanical stability.
Question 5: What does ISO VG 46 mean on a hydraulic oil label?
- The oil has 46% additive content by volume
- The oil has a nominal kinematic viscosity of 46 cSt at 40°C (Correct answer)
- The oil meets ISO standard 46 for oxidation resistance
- The oil contains 46 viscosity index improvers
Correct answer: The oil has a nominal kinematic viscosity of 46 cSt at 40°C
ISO VG (Viscosity Grade) 46 means the oil has a nominal kinematic viscosity of 46 centistokes (cSt) at 40°C as defined by ISO 3448.
Question 6: What is the purpose of an oil analysis program in a reliability maintenance strategy?
- To determine when to change the oil based solely on operating hours
- To detect contamination, wear metals, and degradation trends before failure occurs (Correct answer)
- To verify that the correct oil grade was ordered from the supplier
- To measure the oil's color and odor for quality assurance
Correct answer: To detect contamination, wear metals, and degradation trends before failure occurs
Oil analysis programs detect wear metals, contamination, and oil degradation trends, enabling condition-based oil changes and early warning of developing component failures.
CMRT CMRT Lubrication and Tribology 1
What does the term 'tribology' refer to in the context of maintenance?