The Effect of Drawing Deformation Rate Induced Inhomogeneous Local Distortion on Phase Transformation of 304H Stainless Wire

Abstract

The micro/macro magnetic properties, local element distribution, martensite transformation, and mechanical properties of 304H stainless wires are determined for two cold drawing chains. Finite element simulations are used to analyse the local strain and heat generation. The results show that there is obvious inhomogeneity in the magnetic properties, strain/stress relationship, and strain-induced heat within the drawn wires. Comparing wires with the same total strain, a larger area reduction of previous drawing processes contributes to a higher volume of the martensite phase, while a smaller area reduction of the first process results in an inhibited phase transformation. A higher single strain in the first drawing process leads to additional heat generation at the subsurface of the wire, which would eventually retard the martensite transformation. The inhomogeneous deformation-induced differences in the grain size affect the stability of austenite and transform the final martensite.

Effect of cold deformation on the stress corrosion cracking resistance of a high-strength stainless steel

“…Deformation-induced martensite forms at stacking fault energies below 20 mJ m -2 . Deformation-induced twinning is more likely to occur at stacking fault energies between 20 and 45 mJ m -2 [6,7]. At stacking fault energies above 45 mJ m -2 , dislocations hardly split at all and dislocation slip occurs instead of twinning [7,8].…”

“…Deformation-induced twinning is more likely to occur at stacking fault energies between 20 and 45 mJ m -2 [6,7]. At stacking fault energies above 45 mJ m -2 , dislocations hardly split at all and dislocation slip occurs instead of twinning [7,8]. Heavy cold deformation also leads to the introduction of high residual stresses, whereby tensile residual stresses are usually critical for material failure [9].…”