The Feasibility of Estimating Elastic-Plastic Strain in Powder Structural Steel with Different Residual Porosity by Magnetic Methods
The world’s output of products made of sintered powders is constantly growing due to high productivity and efficiency of powder metallurgy processe s. Safe operation of machine parts and structural components made of sintered powder ma t ials calls for reliable methods of nondestructive testing. The paper presents a procedure of t wo-parameter testing of product structure and porosity, as well as results of investigatio ns into the effect of tensile stresses on the magnetic characteristics of powder structural stee with different residual porosity; it also discusses the applicability of the results for estimat ing elastic-plastic strains.
Correlation between the stress-strain state parameters and magnetic characteristics of carbon steels
A method for reconstruction of the stress-strain diagrams of steel objects from their magnetic characteristics determined directly during tension has been suggested. The coercive force, residual induction in the major hysteresis loops, and the maximum magnetic permeability are recommended as parameters for nondestructive testing of stresses and strains.
The effect of compressive plastic deformation on the magnetic properties of AISI 4130 steels with various microstructures
The magnetic properties of AISI 4130 steel after eight heat treatments have been investigated. Properties such as hysteresis loss, coercivity, and initial permeability were found to be closely interrelated. Furthermore, they were each dependent on the hardness of the material. A relationship between the hardness and permeability was found which was microstructure independent. These parameters were also found to change in a systematic way with plastic deformation and this result can be used for non-destructive evaluation. Correlations between the magnetic parameters were also found to change in a systematic way with plastic deformation and this result can be used for non-destructive evaluation. Correlations between the magnetic parameters revealed relationships which depended on the microstructure of the material. The residual stress in steels can be determined from the changes in maximum differential permeability.