Four Ball Tester and Its Application

Four Ball Tester and Four Ball Testing Method

Abrasion resistance test of oil (four-ball test):

The PB value is also the maximum non-jamming load and is a typical indicator of the anti-wear performance of lubricants. The PD value is an extreme pressure performance index, and ZMZ is called the comprehensive wear index. The testing machine adopts four-ball sliding friction form. Under the condition of extremely high point contact pressure, evaluate the bearing capacity of lubricating oil, including the maximum non-occluding load PB, sintering load PD, comprehensive wear value ZMZ and other three indicators:

1. Maximum load without seizure PB (representing oil film strength): The highest load at which no seizure occurs between the upper and lower steel balls under the specified test conditions.          

2. Sintering negative PD(N): The lowest load level of sintered steel balls is called sintering load, which represents the ultimate working capacity of the lubricant.

3. Comprehensive wear value ZMZ: also known as comprehensive wear index, average Hertz load, load-wear index, etc. It is an indicator of the ability of lubricants to resist extreme pressure. It is equal to the digital average of multiple calibration loads. The larger the ZMZ value, the higher the anti-wear performance of the lubricant and the stronger the ability to discriminate extreme pressure additives.
   

Advantages of Four Ball Testing Method:

Compared with other friction and wear test methods, the four-ball testing method has a higher degree of similarity for common friction pairs such as bearings, and is easy to achieve the standardization and consistency of the paired pairs. It is often used to screen and evaluate lubricants. The four-ball testing machine can realize the simulation test of actual working conditions by replacing the friction pairs and adjusting the control parameters. The four ball tester is a device for evaluating the anti-wear performance of lubricants and distinguishing their low, medium and high extreme pressure performance.

Automatic Four Ball Friction Tester (measurable friction coefficient):

The four ball tester can be used to determine the anti-wear performance of lubricants and evaluate the load-bearing capacity of lubricants, including constant wear, maximum seizure load PB, sintering load PD, comprehensive wear value ZMZ, friction coefficient and friction curve.

1. Determine the constant wear, PB, PD, ZMZ, friction coefficient and friction curve. 

2. Leverage type, the loading force is constant and no fluctuation during the test. 

3. High-precision friction force sensor, real-time display of friction force, friction system and change curve 

4. Axial test force: 40N~10KN