CLS Grease Technology & Application 2

Question 1

Which thickener type provides the highest dropping point among common grease thickeners?

Accepted Answer

Bentone (clay)

Answer

Lithium 12-hydroxystearate

Answer

Calcium soap

Answer

Polyurea

Question 2

What does the worked penetration test (ASTM D217) measure in grease?

Accepted Answer

The depth a standard cone penetrates the grease after 60 strokes of a worker

Answer

The viscosity of the base oil after separation

Answer

The temperature at which grease hardens under pressure

Answer

The water resistance of grease at elevated temperatures

Question 3

What is the main advantage of calcium sulfonate complex grease over conventional lithium complex grease?

Accepted Answer

Inherent EP and rust protection without requiring additives

Answer

Lower cost of manufacture

Answer

Better low-temperature performance below -40°F

Answer

Superior compatibility with all other grease types

Question 4

In a centralized automatic grease lubrication system, what is a primary advantage over manual re-greasing?

Accepted Answer

Delivery of smaller, more frequent grease quantities while equipment is running

Answer

Ability to use higher NLGI grade greases

Answer

Elimination of the need for grease nipples (zerk fittings)

Answer

Reduced need for grease compatibility verification

Question 5

What is 'channeling' behavior in grease and why can it be beneficial?

Accepted Answer

Channeling is when grease forms a channel allowing the bearing to run through the grease without churning it, reducing heat generation

Answer

Channeling means grease flows to the bottom of the housing, which prevents over-lubrication

Answer

Channeling refers to grease migrating through seals, which helps prevent seal wear

Answer

Channeling occurs when grease hardens into channels, improving its load-carrying capacity

Question 6

Which test method is commonly used to evaluate the water washout resistance of grease for wet environments?

Accepted Answer

ASTM D1264 (Water Washout Characteristics)

Answer

ASTM D2266 (Four-Ball Wear)

Answer

ASTM D217 (Cone Penetration)

Answer

ASTM D2596 (Four-Ball EP)

Question 7

What is the recommended practice when mixing two different grease types in a bearing housing?

Accepted Answer

Mixing greases should be avoided; perform a compatibility test or completely purge old grease before switching

Answer

It is always acceptable as long as both greases have the same NLGI grade

Answer

Mix only if both greases use the same base oil viscosity

Answer

Mixing is acceptable for soap-thickened greases but not for clay-thickened greases