METHOD FOR DETERMINING OF FRICTION COEFFICIENT FOR PLASTIC DEFORMATION AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2018 - IPC G01N19/02 

FIELD: technological processes; measurement technology.

SUBSTANCE: invention relates to the field of studying friction in the treatment of metals by pressure, in particular to methods and devices for studying the friction coefficient of plastic deformation. Sample is deformed, then the deforming force, the contact area of the sample with the tool surface, the surface area of the side, the frictional force and the required coefficient of friction are determined. Sample is made rectangular with side a, height h, and the dimensions of the sample must satisfy the condition h/a = 1...1.5. Sample is placed in the U-shaped groove of the cage. On top of the sample, there is a press punch driven by the press beam. Ends of the sample on opposite sides support the retaining and pushing punches. Sample is deformed by the pushing punch, maintaining a constant pressure on the retaining punch, first, the deformation of the sample is carried out under the condition that the average pressure on the cage walls is less than the yield stress of the sample material, then the sample is deformed under the condition that the average pressure on the cage walls is equal to the yield stress of the sample material, on the next step, the sample is deformed under the condition that the average pressure on the cage walls is much greater than the yield stress of the sample material, the friction coefficient for each case is calculated by the calculation method. From the values obtained, a plot is plotted of the stress of the sample on the change in the coefficient of friction. Device contains a holder for the installation of a deformable sample, punches mounted in a holder with the ability to move by means of a drive, and measuring devices. Device comprises a pressure punch for deforming a square section pattern associated with the press slider and being movable in a vertical direction. In the clip on both sides perpendicular to the pressure punch are installed pushing and retaining punch, having the possibility of moving in the horizontal direction.

EFFECT: ability to accurately determine the coefficient of friction, as well as modeling the processes of processing materials with pressure, creating different stresses in the sample (including all-round compression), and to determine the coefficients of friction for different types of lubrication.

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