Notched Constant Ligament Stress Tester
Standards
ASTM 5397–99 《Test Method for Evaluation of Stress Crack Resistance of Polyolefin Geomembranes Using Notched Constant Tensile Load Test》
ASTM F2136-18《Notched, Constant Ligament-Stress Test to Determin Slow-Crack-Growth Resistance of HDPE Resins or HDPE Corrugated Pipe》
Application
It is used to determine the susceptibility of high-density polyethylene (HDPE) resins or corrugaed pipe to slow-crack-growth under a constant ligament-stress in an accelerating enviroment.
It is intended to appy only HDPE of a limited lelt index (＜0.4 to 0.15＝ and density range (＞0.947 to 0.955g/cm3). It may be applicable for other matierials, but data are not avialble for other materials at this time.
Test Methods
Brittle transition time determination method: it is used to determine whether the specimen is broken within the set time. If it is broken, it is unqualified; if it is not broken, it is qualified. When it reaches the set time, it will automatically stop the test and prompt it.
Brittle transition time measurement method: it is used to measure the constant load time when the specimen breaks, and the loading time is recorded automatically during the test.
Features
1. With the function of automatically maintaining the power loss, automatically saving the test time and other parameters in case of unexpected power failure, disconnecting the load, automatically controlling the water temperature heating after the call, reaching the set temperature, automatically loading, and automatically accumulating the time.
2. With accurate level control function, the level control accuracy can be up to 2mm, can accurately control the concentration of immersion solution.
3. With the function of automatic loading and unloading. Each sample holder contains 5 stations, and each sample holder can control loading and unloading independently. After installing the sample and load, click the loading button on the screen, and the system will automatically load and start the timing.
4. There is a partition between the test rack and the test rack body, which can effectively reduce the evaporation of water vapor and affect the concentration of test liquid.
5. It has good anti-corrosion function. The material in contact with the test liquid is 316L or tetrafluoroethylene, which can effectively avoid the corrosion of the test chamber by the solution.
6. With automatic auxiliary load calculation function, system integrated load calculation tool, automatically calculate each station load
7. A sloping drainage, located in the middle of the bottom, is designed to eliminate the water generated by the failed test station in time, largely reduce the influence on other test stations.
Technical Parameters
1. Test temperature: RT to 80℃;
2. Temperature accuracy: ±0.5℃
3. Number of test stations: 20 (may test 20 specimens)
4. Lever ratio: 1:3
5. Max. load: 1.5kg (load on specimen is up to 4.5kg)
6. Timing range: 0 to 9999h
7. Timing accuracy: ±10s
Optional Accessory: Notch nicking device
