RU95577U1 - DEVICE FOR DETERMINING LATER PRESSURE DURING AXIAL PRESSING OF MECHANICAL MIXTURES WITH THE PRESENCE OF A LIQUID PHASE - Google Patents

Abstract

A device for determining lateral pressure during axial pressing of mechanical mixtures with the presence of a liquid phase, containing a matrix, a punch, resistance strain gauges, characterized in that the matrix is pentahedral, through cylindrical holes are made in each face, in which smooth rods are installed, elastic racks are brought to them with attached resistance strain gauges.

Description

The utility model relates to powder metallurgy and, in particular, to recording devices during the pressing of metal powder, and can be used, in particular, for recording and quantitative determination of lateral pressure in the processes of axial pressing of high-density powder multiphase mechanical mixtures in rigid molds.

A device is known for measuring pressure, and in particular lateral pressure, including a rigid mold and a strain gauge (one) glued either to the matrix wall (see D.I. Ageikin, E. I. Kostina, N. N., Kuznetsova. Control sensors and regulation. References. Mashgiz, 1965), or on the lower punch (see G. M. Zhdankovich, Ch. A. Yakubovsky. Pressure and density distribution in hard matrices / Powder metallurgy, 1997, No. 12, p. 46-53) containing a rigid mold (solid matrix and punch) with a strain gauge glued to the side surface, register mechanical elastic deflection of the matrix wall. The disadvantages of this device are:

- A significant error in the measurement of lateral pressure in the study of the whole matrix, in view of the significant rigidity of the side wall of the matrix, the small value of its elastic deflection and, as a result, the need to use high-precision strain gauges, which significantly reduces the constructive expediency of this device.

- The magnitude of the pressure gradient along the longitudinal axis of the pressing is not taken into account, depending on the stage of pressing and the pressing zone during multiphase structure compaction (in the presence of a liquid medium), as a result, only integral (averaged) lateral pressure values are recorded, which does not allow the strength calculation of the matrix to be performed correctly.

This device is taken as a prototype. The prototype and the claimed utility model have the following similar essential features:

- The main loadings are made using a deforming punch;

- Lateral pressure is perceived by the side wall of the matrix.

EFFECT: increased accuracy of lateral pressure measurement on the matrix walls, stepwise registration of lateral pressure value.

The technical result is achieved by the fact that the device for determining lateral pressure during axial pressing of mechanical mixtures with the presence of a liquid phase, contains a matrix, a punch, resistance strain gauges.

The peculiarity is that the matrix is pentagonal, through cylindrical holes are made in each face, in which smooth rods are installed, elastic struts with attached resistance strain gauges are brought to them.

The need to use a five-sided matrix, through cylindrical holes in which smooth rods are installed, elastic struts with attached resistance strain gauges, is caused by a five-stage scheme of pressing powder materials in the presence of a liquid phase and, as a result, a five-stage change in the physicomechanical properties of the densified heterogeneous multiphase structure (see B. N. Kokorin Interparticle splicing in the process of consolidation of discrete iron-containing powder materials /

Bulletin of the Saratov State Technical University. Saratov. - SSTU 2009 №1. - from 71-74.)

The lateral pressure (P _b ) and the lateral pressure coefficient ξ are determined by the elastic properties of the base metal of the mechanical mixture E _m and the volumetric compression coefficient of the liquid E _w , which at each stage of pressing (compaction) iteratively measure their value, is a function of the current density. The lateral pressure coefficient is given by the formula:

where ξ is the lateral pressure coefficient;

E _m - the modulus of elasticity of the metal base of the mechanical mixture;

E _W - coefficient of volumetric compression of the liquid;

ε _W - volumetric compression coefficient of the liquid;

µ _m — Poisson's ratio of the base metal;

The use of a differentiated (step-by-step) lateral loading scheme of strain gauge sensors mounted on elastic struts allows you to record a change in the nature of the power regime of compaction of multiphase mechanical systems.

The essence of the utility model is illustrated by drawings, where in Fig.1 shows the design of the device for determining lateral pressure, in Fig.2. the arrangement of load cells is presented, in Fig.3. strain gauge is presented.

The device contains a five-sided matrix 1, in the faces of which through cylindrical holes 2 are made, in which smooth rods 3 are installed, to which elastic struts 4 with attached resistance strain gauges 5 are connected.

The operation of the device is as follows:

Moistened powder is fed into the working cavity of the pentahedral matrix 1. Pressing is carried out by the punch 6 according to the scheme of static one-sided loading. Under the action of axial force (pressure q), the base metal (discrete powder particles) transmit pressure in a horizontal plane; the liquid phase, which is part of the moistened powder, also exerts a force pressure in the horizontal direction due to the Laplace pressure. When this occurs loading on a smooth rod 3, its horizontal movement, and as a result, the horizontal deviation of the elastic strut 4 with a glued strain gauge 5. Registration and fixing of the lateral pressure at the first stage of pressing. With further lowering of the punch 6 (further static loading), the main force loading occurs on a smooth rod 7 with subsequent registration of lateral pressure through an elastic strut and strain gauge 8.

Similarly, loading and registration of lateral pressure is carried out at subsequent stages of pressing.

The inventive utility model does not adversely affect the state of the environment.

Claims (1)

A device for determining lateral pressure during axial pressing of mechanical mixtures with a liquid phase, containing a matrix, punch, resistance strain gauges, characterized in that the matrix is pentagonal, through holes are made in each face, in which smooth rods are installed, elastic struts are brought to them with attached resistance strain gauges.