Test Method of Grease Cone Penetration
author: Ann
2024-07-01
Cone penetration represents the consistency of grease, which refers to the degree to which plastic materials such as grease resist deformation when subjected to force. Consistency is a characteristic of plasticity, just as viscosity is a characteristic of fluidity.
The consistency of grease is often expressed by cone penetration. Cone penetration refers to the depth of a cone of a certain weight and shape that falls into the grease within 5 seconds under specified measurement conditions, expressed in 1/10mm. In fact, the numerical value of cone penetration measurement is opposite to the consistency. The smaller the cone penetration of the grease, the greater the consistency and the harder it is; the larger the cone penetration, the smaller the consistency and the softer it is.
Cone penetration measurement method
Cone penetration is an important indicator in the quality assessment of grease, and each country has a standard method for measurement. my country's standard method is GB/T 269; the International Organization for Standardization method is ISO/DP2137; the American Society for Testing and Materials standard method is ASTM D217. The shape and weight of the standard cone are strictly regulated, and the mass of the cone and rod is 150g.
According to the measurement methods at home and abroad, cone penetration is divided into the following five types:
1. Working cone penetration
The so-called working cone penetration refers to the shearing effect of grease in the working device. The size of the perforated disc of the working device and the size and position of the holes are specifically specified. When the pull rod drives the disc up and down, the grease sample is sheared. When measuring, the grease sample is first kept at 25℃, and the working device is used to work at a speed of 60 times per minute (the pull rod reciprocates up and down as 1 time) for 1 minute, and then measured at 25℃. The measured result is the 60-time working cone penetration.
2. Extended working cone penetration
The cone penetration measured when the grease sample works more than 60 times (for example, 10,000 times or 100,000 times, etc.) is called the extended working cone penetration, and the number of working times must be stated at the same time.
3. Unstirred cone penetration
The cone penetration measured at 25℃ for the grease sample that has not been stirred in the original container.
4. Unworked cone penetration
The cone penetration measured at 25°C after the grease sample is moved to a grease cup or a container of the same size with as little agitation as possible.
5. Block cone penetration
The cone penetration of a grease with sufficient hardness to maintain its shape at 25°C.
In addition, the cone penetration of a grease obtained by combining a small cone with a size of 1/4 of the standard cone is called micro-cone penetration. The relationship between grease cone penetration and micro-cone penetration is: A=3.75B+24
A--- Grease cone penetration, 1/10mm;
B--- Grease micro-cone penetration, 1/10mm.
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