1. Salt spray test
Testing method:
Salt spray testing is an accelerated testing method that first atomizes a certain concentration of salt water and then sprays it into a closed constant temperature box. By observing the changes in the hose joint after being placed in the constant temperature box for a period of time, the corrosion resistance of the joint can be reflected.
Evaluation criteria:
The most common criterion for evaluation is to compare the time it takes for oxides to appear on the joint with the expected value during design to determine whether the product is qualified.
For example, the qualification criteria for Parker hose fittings are that the time to produce white rust must be ≥ 120 hours and the time to produce red rust must be ≥ 240 hours.
Of course, if you choose stainless steel fittings, you don’t have to worry too much about corrosion issues.
2. Blasting test
Testing method:
Blasting test is a destructive test that typically involves uniformly increasing the pressure of a newly compressed hydraulic hose assembly within 30 days to 4 times the maximum working pressure, in order to determine the minimum blasting pressure of the hose assembly.
Evaluation criteria:
If the test pressure is below the minimum burst pressure and the hose has already experienced phenomena such as leakage, bulging, joint popping, or hose bursting, it is considered unqualified.
3. Low temperature bending test
Testing method:
The low-temperature bending test is to place the tested hose assembly in a low-temperature chamber, maintain the temperature of the low-temperature chamber constant at the minimum operating temperature specified for the hose, and keep the hose in a straight line state. The test lasts for 24 hours.
Subsequently, a bending test was conducted on the core shaft, with a diameter twice the minimum bending radius of the hose. After the bending was completed, the hose was allowed to return to room temperature, and there were no visible cracks on the hose. Then, a pressure test was conducted.
At this point, the entire low-temperature bending test is considered complete.
Evaluation criteria:
During the entire testing process, the tested hose and related accessories should not rupture; When conducting the pressure test after restoring room temperature, the tested hose must not leak or rupture.
The minimum rated working temperature for conventional hydraulic hoses is -40 ° C, while Parker’s low-temperature hydraulic hoses can achieve -57 ° C.
4. Pulse testing
Testing method:
The pulse test of hydraulic hoses belongs to the predictive test of hose life. The experimental steps are as follows:
- First, bend the hose assembly into a 90 ° or 180 ° angle and install it onto the experimental device;
- Inject the corresponding test medium into the hose assembly, and maintain the medium temperature at 100 ± 3 ℃ during high temperature testing;
- Apply pulse pressure to the interior of the hose assembly, with a test pressure of 100%/125%/133% of the maximum working pressure of the hose assembly. The test frequency can be selected between 0.5Hz and 1.3Hz. After completing the corresponding standard specified number of pulses ， the experiment is completed.
There is also an upgraded version of pulse testing – flex pulse testing. This test requires fixing one end of the hydraulic hose assembly and connecting the other end to a horizontal moving device. During the test, the movable end needs to move back and forth at a certain frequency
Evaluation criteria:
After completing the required total number of pulses, if there is no failure in the hose assembly, it is considered to have passed the pulse test.
Post time: Oct-09-2024