Dotting and distance marking device for tensile test of metal test piece

The invention discloses a metal test piece tensile test dotting and distance marking device, which relates to the technical field of metal tensile tests, and comprises a dotting and marking assembly, a diameter measuring assembly and a control assembly, the dotting and scribing assembly comprises a supporting table, a dotting piece, a positioning piece, a position adjusting piece, a transmission wheel and a first pushing piece. The diameter measuring assembly comprises a first diameter measuring piece, a second diameter measuring piece, a third diameter measuring piece, a first distance adjusting piece and a second distance adjusting piece, the control assembly comprises a controller and a limiting stopper, and the first diameter measuring piece, the second diameter measuring piece and the third diameter measuring piece can be adjusted to be located at the two ends and the middle of the metal test piece correspondingly; therefore, the outer diameter of the metal test piece can be measured at one time, which i