How to choose a suitable torsion testing machine?

Many customers choose to step on the pit, mostly because of the wrong torque range, mismatched sample clamping, or the equipment can't measure data, or it is directly out of range. Remember these key points of selection:



Determining torque range (core point)

First, estimate the torque when the sample is damaged, and it is suggested that the range of equipment should be 1.2~2 times of the damage torque of the sample. Example: the fracture torque of the sample is about 800N・m, so the 1000N・m or 2000N・m model should be selected first; Don't choose equipment just equal to the destruction torque, which is easy to overload. Tip: Don't blindly pursue a large range. The larger the range, the lower the accuracy of small torque test. Do thin rod and small bolt tests, select small range models, and the data will be more accurate.



Specimen specification and clamping fixture

Conventional round bar sample: standard three-jaw self-centering chuck is enough; Hexagon samples, plates, special-shaped parts and short samples: it is necessary to communicate and customize special tooling in advance; Confirm the maximum length of the sample and check the effective clamping stroke between two chucks of the equipment.



Test control mode

Static material torsion (measuring yield torque, torsional strength and shear modulus): microcomputer servo torsion testing machine (this one in this paper), with angle/torque double closed loop, is suitable for quality inspection and scientific research, and belongs to a widely used model; Repeated twisting and alternating torsion fatigue test are required: a torsion fatigue testing machine should be selected, and ordinary static torsion machines cannot do alternating torsion test.



Accuracy grade and standard requirements

First, the testing organization selects the 0.5-level precision model; The internal quality inspection of the enterprise can meet the requirements of GB/T10128 "Room Temperature Torsion Test Method for Metal Materials" with the accuracy of Grade 1. Confirm in advance that the software has built-in national standard algorithm, which can directly output the original records and test reports that meet the specifications.



Additional expansion demand

If there is a need to expand the test in the future, it can be confirmed in advance whether the equipment supports the installation of torsion extensometer to measure shear modulus, high and low temperature environment box, multi-channel data acquisition module, etc.