Common testing methods of hongjin tensile testing machine

Common testing methods of hongjin tensile testing machine

In modern industry, material testing machines have been widely used in mechatronics, military industry, construction, plus points, automobiles, shipbuilding and aerospace. With the continuous improvement of precision measurement technology, more and more
The material testing machine with cash performance, which can be used in different occasions and can be adapted to different requirements. The scientific and reasonable use of the material testing machine can achieve cost reduction, process improvement, product quality improvement, material
The saving of materials and the design of engineering structures are of great significance in modern industry.

1. How to choose the testing machine

In the selection of tensile testing machine
At first, the test force standard and project characteristics must be used as the basis for selection. The engineering construction quality inspection agency must use the experimental test project as a reference basis, and should also consider the corresponding range ratio.
If you need to choose a pressure testing machine for the standard test block of concrete, you need to choose a tensile testing machine to test the tensile strength of the steel bar, you need to choose a bending test machine to test the breaking ability of the floor tile.
If you need to test more content and items, you must choose a tensile testing machine with multiple functions. For example, you need to use a universal tensile testing machine for flexural, compressive, and tensile testing.

Secondly, it is necessary to fully understand the relevant force value transmission system. If it is not aligned with the installation position and force type of the dynamometer, or the specifications of the selected tensile testing machine do not meet the relevant national standards, the tensile testing machine is used. There will be a certain degree of difficulty in metrological verification, so it is necessary to understand the relevant force value transmission system.

Finally, it is necessary to understand the testing force method of the tensile testing machine. As a dosage instrument, the tensile testing machine must meet the relevant national standards. At the same time, the staff must understand the debugging force method.
After learning from each other and the force method introduced by the manufacturer to grasp the force method of the relevant experimental machine. In short, when selecting the tensile test machine, you must understand its debugging force method and verification acceptance method before the contract is formed.

2 Testing requirements for commonly used material tensile testing machines

2.1 Requirements for ambient temperature and humidity

Under normal circumstances, the material testing machine needs to work in the environment of room temperature 10-35 ℃, while also ensuring that the relative humidity is not greater than 80% and the ambient temperature change is not greater than 2 ℃/h.

2.2 Requirements for safety protection devices

The electrical design of the tensile testing machine must ensure that there is no leakage phenomenon and has various safe and reliable performances. At the same time, the tensile testing machine with sensitive and reliable safety devices must be selected to ensure that it has a quick response stroke limit switch.
Once the moving upper and lower chucks appear at the limit position, or the test force exceeds the maximum test force, the installation device must react immediately to achieve automatic shutdown.

2.3 Requirements for installation level

Must be based on a stable basis for the tensile machine
Installation, to ensure that the installation level does not exceed 2mm/m. At the same time, it is necessary to reserve a space of not less than 0.7 cm near the tensile testing machine, and there must be no strong electromagnetic field interference and no vibration around.
Work in a working environment with dynamic, dry, clean and non-corrosive media, and control the power supply voltage within ±10% of the rated voltage.

2.4 Related requirements of surveying system

The zero point adjustment function of the force testing system of the material testing machine with the function of zeroing or zeroing must be used. When the test force is measured, the zero point must be displayed, and at the same time, each function of maintaining the peak must be performed.
During the deformation measurement, the deformation force direction identification function, the maximum deformation value saving function and the zero point adjustment function should be provided. When the different dials of the test force are replaced, the testing machine should be cleared.

2.5 afterburning system

The pressure applied on the pattern should be indicated at any time and continuously in the material testing machine force measurement system. The force indication should be continuous, stable and free from tremor when the test force is removed or applied.
The phenomenon of impact, to avoid abnormal jumps and stagnation. The peak value of the test force before the sample is broken or removed should be accurately retained or instructed to prevent oil leakage and oil leakage in the liquid in the tensile testing machine.
In the process of continuously adding some test force in the compression test machine, the tensile test machine must not show the phenomenon of jitter or stagnation of the pointer operation. To ensure that the active needle and the driven needle have a coincident state, the width of the pointer tip needs to be close
The width of the engraved line, the pointer must also be balanced with the dial table. During the lifting process, it is necessary to prevent any obstruction of the Zhuang force pendulum. When the test force drops sharply, the buffer needs to ensure that the pendulum can Smooth return
Return, so that the return to zero of the pointer is not affected.

3. Commonly used tensile testing machine detection methods and troubleshooting methods

3.1 Detection force method

(1) Check the longitudinal and lateral levels of the main body: the longitudinal and lateral levels of the tensile testing machine’s force-measuring structure need to be checked so as to conform to the relevant standards and regulations;

(2)
Zero adjustment of the tensile force value: between the implementation of the verification, the initial initial state of the tensile test machine needs to be correctly set, and the following measures can be taken to perform the zero adjustment of the hydraulic test machine: ① the use of balanced thallium in A hammer
Perform zero adjustment in the state; ② Use the pretend rod to perform zero adjustment when adding the C hammer; ③ Use the balance thallium to perform zero adjustment when removing the C hammer; ④ Repeat the operation three to four times using the above three steps until B hammer is loading and unloading
Until the zero point remains unchanged;

(3) Check the upper and lower travel limits: set the upper and lower travel limits based on the verified range and the relevant national regulations for safety protection devices;

(4) Check the buffer: it must be ensured that the buffer can be raised normally, and at the same time, the phenomenon of falling off must be avoided;

(5) Check the mechanical value of the tensile test: ① Check whether the dynamometer certificate is valid; ② Install the dynamometer to keep it in working condition; ③ Use the common zero adjustment method for the dynamometer and Tensile testing machine for processing; ④ After full load, pre-compress three times for the dynamometer, and then verify.

3.2 Troubleshooting

(1) The spark plug moving up and down appears to jump: check whether the relief valve is adjusted to the optimal pressure; check whether the oil path to evacuate air; check whether there is hard friction on both sides of the column an examination;

(2) Unbalanced force: check whether the level of the host is misaligned, and adjust it if it is; if there is mechanical friction, check the guide blocks on both sides of the column; Check for instrument failure.