The influence of test speed on the accuracy of the testing machine

The influence of tensile speed on tensile speed, elongation and yield strength of tensile testing machine is mainly discussed. The influence of the tension tester varies with the material, so the test must be carried out strictly in accordance with the rate specified by the standard test method in the tensile test, otherwise it will affect the accuracy of the test results. The test speed of material tension test machine is in 50~500mm/min, some in 0.001~500mm/min, the former usually uses ordinary trapezoidal wire rod plus speed control motor or variable frequency speed control system, the cost is lower, and the wear is bigger. A long time, a lot of experiments will produce the middle plate shaking, affecting the accuracy of the test, and the time will soon be used, the machine will be noisy and easy to break. The latter uses servo system plus ball screw, with high accuracy, constant speed and stability, small wear and good durability. The test repeatability is also good. The standard all stipulates the test condition, what material speed, because the speed is different, the force value measured is also different.
Three common data of the tensile test:
1. Tensile strength: tensile strength increases with the increase of test speed, but it tends to be stable after reaching a certain stage.
2, yield strength: when the test speed is slow, the difference between yield strength and tensile strength is larger, and the faster the test speed is, the difference between yield strength and tensile strength decreases gradually.
3. Elongation after break: the increase of tensile speed decreases the elongation after fracture, and decreases slowly after a certain stage. (in addition, the large tensile strength and the elongation at the end of the fracture are sensitive to the tensile velocity, while the small tensile strength and the elongation at the end of the fracture are relatively less sensitive to the tensile velocity. ” If the servo system of all kinds of production equipment and manipulator is used, we can go to the automobile factory to see if there is an opportunity. Every part of the automobile parts is exactly the same. Therefore, it is recommended that ball screw with servo system can meet users’ requirements. Of course, the test is not much, the power is not easy to choose the ordinary trapezoidal wire rod plus speed control motor or variable frequency speed control system, economic and practical, the same can get the ideal data.
Material drawing machine test machine related system:
Tension test recording system: full automatic force measurement system, stepless gear, can automatically ensure accuracy, and easily measure the accuracy of the indicator to 0.2%, and most energetically as the finest resolution, automatic identification; automatic standard force, standard length correction system, can be calibrated by any metering department for idiot metering. The bilingual test software on the WIN2000, XP platform of the data system is upgraded at any time, and all curves are printed (the most advanced software output curve report). The test data, such as load, deformation, displacement, velocity, tensile strength, fracture strength, elongation and so on, are dynamically displayed during the test. The test results are automatically stored, analyzed, amplified, calculated and counted.
The frame structure is adopted in the mechanical structure, and the high precision ball screw without gap is loaded to ensure the efficiency of the whole steel and load, and there is a larger test space for various tests to ensure the testing function and simple operation of the machine with large load.
In different industries and testing standards, the speed of tension test required is also different. Before the test operation, the parameters and system should be properly adjusted, and the tension test machine should be maintained and maintained regularly so as to ensure the accuracy of the final test results.