Patent ID: 8312764
Filing Date: 2012-11-20
Classification: G01N

Abstract:
1. Apparatus for detecting yield stress σ sn , strain-hardening coefficient n, elastic modulus E, and strain-stress curve σ-ε of metal materials, said apparatus comprising: an indenter constructed and arranged to be pushed against a sample of the material and to penetrate into the material to a penetration depth (h), and that can be correlated to material hardness; a means for generating a predetermined force (F); a means for amplifying the force (F) produced by said means for generating and for applying the force to said indenter to exert a corresponding contact force (P) on the sample, wherein said means for amplifying said force is of an hydraulic type; a means for measuring in successive instants (t1, t2, t3, . . . ti, . . . tN) the value of the contact force (P) of said indenter on the sample; a means for measuring the penetration depth (h) of said indenter into said sample to obtain a penetration value; and a means for analyzing couples of data, each of said couples generated by associating, for each instant of detection, a measured value of the contact force (P) with a relative measured penetration value; wherein said means for measuring said penetration depth (h) comprises at least one position sensor arranged close to said indenter so as to reduce possible linear deformation to which the apparatus is subject while detecting said penetration depth and said force; wherein said position sensor is arranged close to said indenter, and along a circumference concentric to said indenter.