MATERIALS TESTING METHOD FOR DETERMINING POWER PARAMETERS, WHEN PRODUCING HOLLOW BILLETS BY PRESSURE SHAPING Russian patent published in 2017 - IPC G01N3/28 

FIELD: testing equipment.

SUBSTANCE: it is carried out the closed backward extrusion of the "base" cavity, which is a cylindrical cavity with diameter d_P= 10 mm with a flat bottom, in a cylindrical workpiece with diameter D=20 mm and height H=30 mm. Before extrusion of the "base" cavity, using the method of coordinate grids, determine the strain state for a particular hollow billet, and according to the shape of the deformation area the height H_pl is set under the end face of the punch, forming a specific hollow billet, and the parameter S_kp, characterizing the contact surface of the deformed hollow billet with deforming tooling in the deformation area, these parameters are also defined for the "base" cavity, using a relation H_pl/d_p=1.6-1.4(d_p/D) and R_pl/d_p=2-0.32(D/dp), where R_pl - the radius of the deformation area bound. Thermomechanical extrusion parameters of the "base" cavity: T - testing temperature, S_p - punch working stroke, _Vd - the punch working stroke speed, is defined from the conditions of the thermal T_p/T_w= idem, where T_p - punch temperature, T_w - temperature of the workpiece, strain S_p/H_pl= idem, the high-speed V_d⋅η/H_pl⋅σ_s=idem, where η - the viscosity of the workpiece material, σ_s - yield stress of the workpiece material, similar to the process of extrusion the "base" cavity and produce the specifically investigated hollow billet. The deforming force itself, when receiving the specifically investigated the hollow billet, is determined from the relation P_p/R_b=(S_kp)_p/(S_kp)_b, where R_p and R_b - respectively the deformation force, while obtaining a specific studied hollow billet, and while making extrusion of the "base" cavity, (S_kp)_p and (S_kp)_b -, respectively, the surface contact of the deformed workpiece with the deforming tooling in the workpiece deformation area, when receiving specifically studied hollow billet and extrusion of the "base" cavity.

EFFECT: accuracy increase of determining power parameters in the production of hollow billets of unspecified shape by pressure processing in the laboratory conditions at a standard testing facilities with force upto 100 kN; reduction of the labour intensity of pilot programs to determine the force parameters in the production of hollow billets of unspecified shape.

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