Rezumat
CZU 620.1.05:620.171.313
DOI https://doi.org/10.5281/zenodo.2551221
The combination of methods to experimentally study the influence of the deformation rate for high-strength sheet steels (as exemplified by DP780, DP980, and BH 240 steels) on the increase of their plasticity during uniaxial and biaxial stretching is specified. The deformation rates of steels were measured in a wide range – from 10-4 to 17∙103 s-1. To this end, the tensile machine FP 10/1 HECKERT, the hydraulic press machine P6324 with special tools, the Hopkinson-Kolsky machine, and the electro-hydraulic press T1226B were used. The deformations of the materials destruction during the biaxial stretching were determined using a control grid on their surface. Dependences of the destruction deformations of DP780, DP980, and ВН240 steels vs. the deformation rate and their stress-strain state yielding an increase in plasticity of DP780 steel up to 2.9 were identified.
Keywords: electric discharge in water, deformation rate, deformation, destruction, stress-strain state, high-strength sheet steel.