I. Introduction:
In industries such as automotive and construction, the resistance of materials and coatings to gravel impact is crucial. The T201 Gravel Resistant Impact Tester can simulate the impact of splashed gravel on material surfaces in real-world environments, providing important data for evaluating material performance. Below, we detail the standard experimental procedure for the T201 Gravel Resistant Impact Tester.
II. Experimental Preparation:
◎ Equipment Inspection:
The T201 Gravel Resistant Impact Tester should feature easily and quickly replaceable test spray guns to meet VDA and SAE standards, a touchscreen for convenient testing settings, and a flat-plate test specimen angle that can be set to 45°, 54°, and 90° (irregular specimens use a 3D test chamber). Meanwhile, the equipment operates continuously or intermittently. The feeding rate is adjusted via an electromagnetic vibrating feeder. A large-capacity compressed air storage tank maintains constant pressure and flow rate. It is also equipped with multiple safety protection measures, such as a safety power-off device and a pressure safety value protection device, and complies with European CE and EMC certifications. Before the experiment, the integrity and operating status of the equipment must be checked to ensure that all components are working properly, the spray gun, regulating valve, electromagnetic vibrating feeder, etc., are fault-free, and the safety protection devices are sensitive and effective.
◎ Sample Preparation:
Sample Selection: Select appropriate test samples according to the experimental purpose, such as automotive materials and surface coatings, exterior coatings, glass materials, plastics, etc.
Sample Treatment: All test samples should be placed at a 90° angle to the impact direction of the flying stone, unless otherwise specified. Test samples must be placed separately and treated under specific temperature conditions for at least 4 hours. Specific temperature conditions are as follows:
Method A: -18±2℃
Method B: -18±2℃
Method C: 22±5℃ Due to the flow of hot air, the actual temperature of the sample will rise during the test. For Methods A and B, the maximum temperature of the sample is -18±2℃; for Method C, the maximum temperature of the sample is 22±5℃, unless otherwise specified in the material specifications.
◎ Consumable Preparation:
Prepare suitable stone consumables, commonly including standard pebbles (9.5 - 15.9mm), iron gravel (3.5 - 5mm), crushed granite #6 (4.8 - 14.3mm), crushed granite #7 (3.2 - 9.5mm), cast steel shot/steel grit (1.7 - 2.8mm), etc.
III. Experimental Procedure:
◎ Pressure Adjustment:
With the air valve open, adjust the air pressure on the gravel chamber to 480±20 kPa (70 psi). During operation, keep the gravel tank lid closed as a safety precaution.
◎ Adding Consumables:
After adjusting the air pressure, close the air valve, open the gravel tank lid, and then place 473±10 ml of graded gravel in a suitable container.
◎ Placing the Sample:
Place a sample at the ideal test temperature onto the panel holder, with the coated side facing the front of the instrument, and close the gravel tank lid.
◎ Impact Test:
Add gravel every 4±1 seconds. Do not open the air valve before adding gravel. Start the equipment for impact testing. The equipment can be operated continuously or intermittently, completing multiple tests within a short period.
◎ Post-Test Procedure:
After the test, close the air valve, open the gravel tank lid, and remove the panel. Allow the panel to return to room temperature and wipe away moisture, dust, and other contaminants with a cloth.
IV. Result Evaluation:
Cover the test panel with a 100mm long masking tape. Press the tape firmly against the surface using a rubbing motion, then quickly pull it off to remove any loose debris or paint. Evaluate the coating's resistance to gravel impact by observing and analyzing damage to the panel, such as damage to the coating's cohesiveness and the adhesion between different layers.
V. Conclusion:
The standard experimental procedure for the T201 Gravel Resistant Impact Tester must be strictly followed according to the above steps. From experimental preparation to operational procedures and result evaluation, every step is crucial. Only by ensuring the accuracy and standardization of the experimental process can reliable experimental results be obtained, providing strong support for the performance evaluation of materials and coatings, thereby promoting the development of related industries and improving product quality.
