Definition: Penetration refers to the depth, in units of 0.1 mm, that a standard cone freely falls and penetrates into grease contained in a standard cup within 5 seconds. Penetration indicates the consistency or the degree of softness/hardness of the grease.

 

 

Standard Cone Sizes for Penetration Testing:

• Full-size cone penetration
• 1/2 cone penetration
• 1/4 cone penetration

Conversion Formulas:

a. Conversion of 1/4 cone penetration to full-size cone penetration:
P full-size cone penetration=3.75 * P1/4 cone penetration+24
b. Conversion of 1/2 cone penetration to full-size cone penetration:
P full-size cone penetration=2 * P1/2 cone penetration+5

1. Temperature Influence:

• As temperature increases, penetration increases.
• As temperature decreases, penetration decreases.

The greater the penetration, the softer the grease. Conversely, smaller penetration indicates harder grease.

2. Selection Guidelines:

• For surfaces with high loads, choose grease with smaller penetration.
• For surfaces with low loads, choose grease with larger penetration.

 

? Test Standard: GB/T 269 “Test Method for Penetration of Lubricating Grease and Petroleum Grease”, Equivalent Method: ASTM-D217