Fracture Modes of AISI Type 302 Stainless Steel Under Metastable Plastic Deformation

Abstract

Martensitic transformation can be induced by plastic deformation in metastable iron-based alloys, such as stainless steels containing limited amounts of C, Ni and Cr. This transformation takes place at the temperature range from M s and M d , usually at relatively lower temperature values. The transformed martensite has been associated with maximum ultimate strength and relatively high ductility. In the present work, the tensile fracture characteristics of a metastable AISI type 302 stainless steel was investigated in the range of temperatures from -196°C to 25°C. Mechanical properties were compared to those of a stable AISI type 310 austenitic stainless steel. It was found that in 302 steel, its high degree of metastability and dilute dispersion of inclusions result in higher strength and complex modes of fracture, one of which consisting of martensite surrounding globular inclusions.

Different Evolutions of the Microstructure, Texture, and Mechanical Performance During Tension and Compression of 316L Stainless Steel

“…The appearance of this plateau on the tensile stress-strain curve depends on the chemical composition of the studied austenitic stainless steel, the strain rate, and the temperature of tension. [59][60][61][62] The slowly rising stress range was detected in the literature mainly for 301, 302, and 304 types of stainless steel at tension temperatures lower than À 15°C. [59,61,62] In our case, plateau was not observed on the stress-strain curves which can be attributed to the fact that we studied 316L steel at room temperature.…”

“…[59][60][61][62] The slowly rising stress range was detected in the literature mainly for 301, 302, and 304 types of stainless steel at tension temperatures lower than À 15°C. [59,61,62] In our case, plateau was not observed on the stress-strain curves which can be attributed to the fact that we studied 316L steel at room temperature.…”

“…[58] In the beginning of deformation, the increase of a¢-martensite fraction often has a low rate but the c-austenite fi a¢-martensite transformation rate can increase suddenly to a higher value with increasing strain. [59] In this case, the initial region of the stress-strain curve is characterized with a slowly rising stress which then strongly increases when the volume fraction of a¢-martensite is enhanced. The appearance of this plateau on the tensile stress-strain curve depends on the chemical composition of the studied austenitic stainless steel, the strain rate, and the temperature of tension.…”

“…Indeed, former studies have proved a correlation between the strain hardening rate and the evolution of a¢-martensite in stainless steels. [58,59] Namely, when the rate of a¢-martensite formation increased as a function of strain, the strain hardening rate also increased. [58] In the beginning of deformation, the increase of a¢-martensite fraction often has a low rate but the c-austenite fi a¢-martensite transformation rate can increase suddenly to a higher value with increasing strain.…”

Mechanical Response and Failure Evolution of 304L Stainless Steel under the Combined Action of Mechanical Loading and Laser Heating

“…The mechanism for the primarily slow strength degradation is the low sensitivity of strengthening species in 304L stainless steel to modest temperature increases. Later, with the further increase in temperature, the strengthening species start to lose coherency, and favor mechanical degradation [23][24][25][26]. When the continually-heated specimen with limited thermally activated dynamics continually attains strain energy from the preload, it eventually becomes energetically supportive, to relieve the load through fractures in the specimen.…”