SHEET MATERIAL TEST METHOD Russian patent published in 2017 - IPC G01N3/28 

FIELD: metallurgy.

SUBSTANCE: separating grid is applied to the workpiece from the tested sheet material, the workpiece is stacked into the device, the workpiece edge is clamped between the die and the clamp, the workpiece is mould by punch to destruction, and the points are constructed on the diagram of limiting deformations from the grid separating measurement results after testing. From the tested sheet material, a workpiece is cut with dimensions exceeding the dimensions available on the rift holder in plan. Under the workpiece, a temporary spacer is put of the same size as the blank from the material which plasticity parameters are not lower than the ductility of the tested workpiece and the hole in the temporary spacer is made the diameter smaller than the punch diameter. The contacting surfaces of the temporary spacer and the workpiece are degreased, therebetween, powder of rosin type is poured. Before forming, between the punch and the temporary spacer, directly above the punch end inside the rift in plan, anti-friction gasket is placed of such dimensions that, during the test process, the temporary spacer is touching the punch surface only after the anti-friction gasket. The punch end is made flat and undercut and with a radiused edge. On the testing double-acting machine with lower drive and two outer and inner sliders, the hard workpiece clamping edge is made as a rift in plan over the circle, concentric circular contour of the punch in plan, during the outer slider moving up. The workopiece is mould with the bottom up through the anti-friction gasket and temporary spacer by the punch during the internal slider moving up.

EFFECT: reduction of labour, time and cost of building the forming limit diagram of sheet materials, reduced time and improved quality of process design and tooling for sheet stamping, receive savings of sheet material by reducing scrap rates when debugging processes, as well as simplification of the sheet material selection and equipment for parts sheet stamping.

6 cl, 1 dwg