amd-testing-test-brief
Seizure Point Test
In the seizure point test, a stationary block is pressed against a rotating ring with increasing force to determine the maximum load capacity of the lubricant before the system seizes. The test identifies the seizure point, which is the highest load at which the lubricant can no longer prevent metal-to-metal contact, resulting in system seizure.
The key measurements taken during this test are:
- Maximum bearing load: The load applied to the system that causes it to seize.
- Seizure groove size: The extent of damage to the test sample, measured at the seizure point.
If system seizure cannot be reached, the groove size indicates the extent of wear-in necessary for the lubricant to perform effectively under high load conditions.
Creep Test
In contrast, the creep test maintains a constant load on the block as the ring rotates over a set period, simulating long-term operating conditions. This test evaluates the lubricant's ability to prevent wear and deformation under continuous stress, providing a measure of its durability over time.
The key measurements taken during this test are:
- Groove size: The extent of damage to the test sample, measured at the end of a run.
- Motor's current draw: Indicates the amount of friction in the system.
Friction
In both tests, the friction coefficient can be measured using an ammeter connected to the electric motor that drives the rotating ring.
As friction between the block and the ring increases, the motor must work harder to maintain the ring’s rotation, which leads to an increase in the current drawn by the motor.
The ammeter records this current, which is directly related to the torque required to overcome the frictional resistance. By understanding the relationship between the motor’s current draw and torque, the friction force can be calculated, allowing for the determination of the friction coefficient.
This provides real-time data on the lubricant’s performance, especially in response to changes in load and over time.
Data
For both tests involve measuring the friction coefficient using the above method, as well as wear measurement through microscopic analysis and the observation of material creep in the long-term test.
The seizure point test identifies the maximum load capacity, while the creep test provides insights into the lubricant’s long-term reliability.
Together, these tests are essential for selecting lubricants that can perform reliably under both short-term extreme conditions and sustained stress, ensuring the protection and longevity of mechanical systems.