Focus on the test method and common failure analysis of the thermal shock test chamber
The impact tester is a new type of impact tester that can instantaneously measure and record the characteristic curve of the material during impact. It is divided into manual pendulum impact tester, semi-automatic impact tester, non-metal impact tester, digital semi-automatic impact tester, microcomputer controlled impact tester and digital automatic impact tester.
Test method for impact tester:
1. Measure the test thickness according to GB6672, measure one point at the center of all samples, and take the arithmetic mean of the test of 10 samples.
2. Select the punch according to the required anti-pendulum impact energy of the test, so that the reading is between 10% and 90% of the full scale.
3. Calibrate the instrument according to the rules of use of the instrument.
4. The sample is flattened and placed in the holder for clamping. The sample should not have wrinkles or excessive tension. The impact surfaces of the 10 samples should be made uniform.
5. Hang the pendulum on the release device, press the button on the computer to start the test, and make the pendulum impact the sample. The same procedure is used for 10 tests. After the test, the arithmetic mean of 10 samples is automatically calculated.
Test method of impact testing machine and common failure analysis of common failure analysis of impact testing machine:
Common fault one:
The pointer of the dial is poorly sensitive, and there is a stop phenomenon after unloading, or the position of the zero point often changes. There are many reasons for this phenomenon.
1. The pulleys on the rack and their track rails are excessively dusty and rusted. At this point you need to remove the cleaning, plus a little watch oil.
2. The pointer rotation shaft is dirty and should be cleaned.
3. There is contact between the racker and the racker and should be loosened.
4. The buffer back oil is in poor condition and should be adjusted or cleaned.
5. The belt on the force measuring piston is loose or too loose (so that the piston cannot run at a constant speed).
6. The friction force of the force measuring piston in the cylinder increases or is stuck, and the chrome oxide paste is applied to the grinding until normal.
7. The pendulum has obstructions during the lifting process, or the pendulum shaft is too dirty or rusted, causing the pointer to change back to zero.
Common fault two:
When the tensile test is performed, the sample fracture is always broken on both sides. The cause of this phenomenon should first be considered whether the main part of the test machine is installed vertically. If this reason is excluded, the following three aspects are excluded.
1. When the jaws are not clamped, the specimens should be clamped symmetrically according to the requirements.
2, the quality of the jaws is inferior, the teeth are damaged, in addition to affecting the different cores of the jaws, the sample is slipped during the test, making the yield point difficult to identify. The jaws should be replaced at this time.
3. The adjustment of the lifting guide wheel is not correct, so that the upper and lower jaws are not concentric. A test rod shall be machined, and the upper and lower jaws shall be tensioned and measured with a dial gauge based on the two force columns until the adjustment is passed.
Common fault three:
The position of the pendulum is not normal, and the pendulum is not allowed to be vertically marked.
The main reason is that the viscosity of the oil is too large or the oil is too dirty. Remedy: Replace the oil with the right viscosity.
The force measuring piston rotates with a large friction or does not rotate. Remedy: Check the impact tester for level and eliminate the force piston failure.
There is unstable friction. Remedy: Clean the pendulum shaft bearing, the toothed rod, the pointer, the wire wheel, adjust the level of the test machine, and reduce the unstable friction.
Common fault four:
The hammer is not normal, and it is fast and slow.
Normally, the buffer can be rotated to the proper position. However, if the oil hole of the damper is clogged, or if the ball of the buffer valve and the inlet contact portion are excessively smeared or the gap is too large, the damper may be disabled. The solution is to clean the buffer valve and adjust the gap between the steel ball and the valve seat to be around 0 or 5 mm. Place the oil needle knob to reduce the gap between the oil needle and the valve body, and re-list the A, B, Cç £ marks. Also, when the temperature influence is large, the oil can be appropriately replaced.
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