CONCLUSION
1. The actual scientific and practical task of increase of efficiency of production
of bimetallic tubular elements in machine-building production is proved and solved –
for the first time on the basis of generalization of results of the analysis of scientific
publications the idea is offered, the machine-building concept of process of production
of bimetallic tubular elements from separate sheet dissimilar metals is developed,
theoretically and experimentally proved with a thinning in the heated state which is
based on the existing theories of diffusion connection of dissimilar metals by
realization of conditions of joint deformation, pressure, heating on their boundary
surfaces.
2. A complex method of theoretical and experimental study of the process of
drawing with thinning of a two-layer blankt of dissimilar metals is developed.
Evaluation of the stress-strain state and energy-force parameters of the process in the
deformation zone is performed using the theory of plastic flow in deformation and the
basics of the theory of composite materials in the interaction of layers of dissimilar
metals on the limiting surface, as well as extreme energy principles of plastic
deformation taking into account the friction forces. The substantiation of analytical
results and results of numerical modeling is carried out with the help of full-scale
experiment with the use of standardized methods on the certified equipment.
3. Using the theory of plastic flow, a mathematical model of deformation of the
process of joint drawing with thinning of two dissimilar metals with heating under
conditions of flat deformed state was developed, which allowed to establish the
relationship between the parameters of the stress-strain state on the limiting surface
and the degree of deformation of thin layers with the initial geometric parameters of
the workpiece, the mechanical properties of individual layers and the geometry of the
working surface of the matrix. It is shown that the error does not exceed 10 for the
calculation of the thickness of the layers with the ideal plastic model of metals...14%
in relation to experimental data. The use of extreme energy principles of deformation,
taking into account the friction forces on the boundary surfaces, has improved the
accuracy of determining the thickness of the layers after deformation to 10...11%.
4. As a result of numerical simulation of the process in the CAD / CAE DEFORM-
3D system, it is found that for pulling with a degree of deformation, the thinning of
50% for the bimetal of the aluminum + titanium system with a minimum coefficient of
friction (=0,01) the maximum values of the drawing force do not differ significantly,
and when = 0,3 there is an increase in the force as well as the work of pulling while
reducing the taper angle of the matrix from 10º to 4º by 45...47%. The value of radial
stresses on the limiting surface of the layers increases in proportion to the degree of
compression, and their maximum value corresponds to the zone close to the output of
the matrix and increases with decreasing taper angle of the matrix. In this case, the
- 531 -