Characteristics of macrolocalization plastic deformation under uniaxial tension steel objects and their resistance to ductile fracture

Purpose. On the basis of the comparative analysis of theoretical prerequisites and experimental results to justify the use of uniform deformation and strain hardening characteristics on Consider-Hart as parameters of resistance of steel viscous destruction. Methodology. Analytical study of modern concepts about the conditions of microlocalization plastic deformation in combination with experimental studies on the behaviour of steel under load objects from low-carbon steel in soft and hardened by cold deformation and strain ageing of structural conditions using including large samples of experimental data and their statistical treatment. Findings. Obtained depending on the structural state of the four main types of charts of deformation and fracture characterizing in including the resistance of viscous destruction shown a beneficial effect on the level of intensity of strain hardening, and confirmed a statistically favorable impact on the value of uniform deformation in the framework of the canonical equations of Consider-Hart. Offered: as explanation for the observed quantitative deviations in the experiment from the above equations, and use them as estimates of the magnitude of the dispersion property of micro volumes. It justifies the use of the uniform deformation value indicating the deviation of this value from the values of the coefficient of strain hardening as a measure of resistance of viscous destruction. Originality. First proposed and justified theoretically characteristic of the viscous resistance to fracture of steel in the form of the value of uniform deformation taking into account the deviation values determined from experiment the values of the coefficient of strain hardening as a measure of dispersion in a distribution of speed values of strain hardening in micro load of the object. It was shown that at a sufficiently large volume of sample and the correct determination of the values of uniform strain ер, the coefficient α in the equation ер = αn (Consider-Hart), where n is the strain hardening coefficient, close to unity. Practical value.Proposed to include in the list of properties defined by acceptance tests cold-formed products, especially susceptible to lowtemperature (to 100 ° C) deformation aging, a new characteristic of the viscous resistance destruction: ер indicating the deviation (n-ер). Proposed mode of aging that increase the value of ер and reduce the value of (n-ер).