# Testing Grease Consistency

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Examination of Consistency Tests

#### 2.1. Cone Penetration Test

#### 2.2. Rheometer Oscillatory Tests

#### 2.3. Alternative Penetration Tests

## 3. Details of Rheometer Penetration Test

^{−1}was induced for 5 s before commencing measurement. Finally, the 5% trim with relaxation period means that after trimming the sample at 5% above the measurement gap, the top plate is lowered to the measurement gap and a pause of 20 min is taken before commencing measurement.

## 4. Comparison of Tests

#### 4.1. Materials and Procedures

#### 4.2. Identifying Variables

^{−1}for 5 s prior to measuring the critical stresses was done to intensify the effects of sample manipulation during testing and assess the sensitivity of the test to initial conditions. This investigation revealed that pre-shear had a significant effect on calculating yield stress but had a small effect on calculating crossover stress. Due to the relatively large standard deviation observed when using pre-shear, it was not used for subsequent tests.

#### 4.3. Rheometer Penetration Test Results

#### 4.4. Oscillatory Test Results

## 5. Discussion

#### 5.1. Rheometer Penetration

#### 5.2. Cone Penetration

#### 5.3. Critical Stress

## 6. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 3.**Rheometer penetration results of PU2 with a 4 N normal force comparing a standard 5% trim to a 100% trim, a pre-sheared sample, and to a sample relaxed for 20 min.

**Figure 6.**Comparison of (

**a**) yield stress and (

**b**) crossover stress of LiC2 worked for 60 strokes using an overfilled sample compared to a pre-sheared sample compared to a standard 5% trim.

**Figure 8.**Comparison of (

**a**) yield stress and (

**b**) crossover stress with rheometer penetration at a force of 5 N for various grease types.

**Figure 12.**Cone penetration (CP) vs crossover stress (CS) for various grease types with a power fit.

**Figure 13.**Smooth texture of worked grease in the cup below compared to the rough texture of unworked grease above it.

**Table 1.**National Lubricating Grease Institute (NLGI) grades and applications [18].

NLGI Grade | Penetration [dmm] | Food Equivalent | Common Application |
---|---|---|---|

000 | 445–475 | Ketchup | Gear boxes/low temperature use |

00 | 400–430 | Yogurt | Gear boxes/low temperature use |

0 | 355–385 | Mustard | Centralized lubrication systems |

1 | 310–340 | Tomato paste | General purpose bearings |

2 | 265–295 | Peanut butter | General purpose bearings |

3 | 220–250 | Butter | High-speed bearings |

4 | 175–205 | Frozen yogurt | Very high-speed bearings |

5 | 130–160 | Fudge | Low-speed journal bearings |

6 | 85–115 | Cheddar cheese | Very slow journal bearings |

Grease Abbreviation | Thickener Type | Labeled NLGI Grade |
---|---|---|

LiC00 | Lithium complex | 00 |

LiC0 | Lithium complex | 0 |

LiC1 | Lithium complex | 1 |

LiC2 | Lithium complex | 2 |

LiC3 | Lithium complex | 3 |

AlC2.1 | Aluminum complex | 2 * |

AlC2.2 | Aluminum complex | 2 |

CaS2 | Calcium sulfonate | 2 |

PU2 | Polyurea | 2 |

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Gurt, A.; Khonsari, M.M.
Testing Grease Consistency. *Lubricants* **2021**, *9*, 14.
https://doi.org/10.3390/lubricants9020014

**AMA Style**

Gurt A, Khonsari MM.
Testing Grease Consistency. *Lubricants*. 2021; 9(2):14.
https://doi.org/10.3390/lubricants9020014

**Chicago/Turabian Style**

Gurt, Alan, and Michael M. Khonsari.
2021. "Testing Grease Consistency" *Lubricants* 9, no. 2: 14.
https://doi.org/10.3390/lubricants9020014