Performance and classification of spring testing machine

The property that metal materials can undergo permanent deformation before being damaged by force is called plasticity. Plasticity index is usually expressed by elongation and reduction of area. The higher the elongation and reduction of area, the better the plasticity.
When a metal sample of a certain size and shape is broken by an impact load in a specified type of impact test, the impact energy consumed per unit cross section at the notch of the sample is called the impact toughness and expressed by αk. At present, the commonly used 10×10×55mm, with a 2 mm deep V-notch Charpy impact specimen, the impact energy (J Joule value) AK is directly used in the standard instead of the αK value.

Because the impact energy per unit area has no practical meaning. Impact energy is the most sensitive to checking the brittleness transformation of metal materials at different temperatures, and catastrophic breaking accidents under actual service conditions are often related to the impact energy and service temperature of the material. Therefore, the relevant standards often specify the value of the impact energy at a certain temperature, and also specify the technical condition that the FATT (fracture area conversion temperature) is lower than a certain temperature.

The so-called FATT is the temperature at which a set of impact specimens at different temperatures are broken and the impact fracture is evaluated, when the brittle fracture accounts for 50% of the total area. Due to the influence of steel plate thickness, for steel plates with thickness ≤10mm, 3/4 small size impact specimen (7.5×10×55mm) or 1/2 small size impact sample (5×10×55mm) can be obtained. But it must be noted that the impact energy values ​​of the same specification and the same temperature can be compared with each other. Only under the conditions stipulated by the standard, can it be converted into the impact energy of the standard impact specimen according to the standard conversion method, and then compared with each other.

The spring testing machines currently on the market are mainly divided into three categories, spring tension and compression testing machines, spring torsion testing machines and spring fatigue testing machines.

Spring tension and compression testing machine    spring tension and compression testing machine can be divided into manual spring tension and compression testing machine, automatic spring tension and compression testing machine and microcomputer controlled spring tension and compression testing machine according to its operation mode. Manufactured according to the technical requirements stipulated by the national spring tension and compression testing machine standard, such as tension springs, compression springs, disc springs, tower springs, leaf springs, circlips, leaf springs, composite springs, gas springs, mold springs, special-shaped springs and other precision springs Strength test and analysis of tension, pressure, displacement, stiffness, etc.

The main functions of the spring torsion testing machine: digital display of torsion torque and angle, angular displacement sensor (photoelectric encoder) for angle measurement, automatic correction of the angular displacement of the torque sensor, the machine also has peak holding, overload protection, stiffness Calculation, result printing, data query and other functions, manual loading, left and right rotation free selection, compact structure, simple operation, fast detection speed, and the test piece is placed vertically on the torque plate during measurement, which is convenient for clamping.