Pressure induced martensite transformation in plain carbon steel

Abstract

In the present study, plain low carbon steel with 0·033 wt- carbon content was subjected to severe pressure during continuous cooling from austenite region. The pressure increased gradually and then suddenly released by the breakdown of ram under pressure. As a result, a microstructure composed of 80 lath martensite and 20 ferrite was produced. Results showed that the martensite formation is not due to the effect of cooling rate but the effect of hydrostatic pressure on the austenite to ferrite transformation start temperature Ar3.

The influence of high temperature due to high adhesion condition on rail damage

“…For some cases (2 and 6), the temperature values were too low to generate WEL even after several wheel passes. However, it was known that the hydrostatic pressure would promote the WEL formation by decreasing the temperature of the austenite transformation [33]. The WEL, therefore, can still potentially be generated in these cases.…”

“…This layer known as white etching layer (WEL) [31] due to the white appearance after etching in Nital is brittle, and can be the spot for crack initiation. This layer is formed at about 720 1C [32] but high hydrostatic pressure reduces the temperature at which this later can form [33]. Caroll et al [34,35] simulated the WEL in the laboratory by two different ways: spot welding and rolling/sliding test machine.…”

Microstructure evolution and mechanical properties of ultrafine grained IF steel via multipass differential speed rolling

“…1 Considering the current demand for high strength steel satisfying the enhanced safety and durability of vehicles, the sheet forming process for fabricating IF steel with an ultrafine grained (UFG) structure might be of interest in the field of the automotive applications. The introduction of the uniform UFG structure in bulk materials was achieved utilising cutting edge technologies, such as high pressure torsion, 2,3 multiaxial forging 4 and equal channel angular pressing (ECAP), [5][6][7] due to their capabilities to impose the considerable amount of plastic strain during processing. Nevertheless, the inherent shortcoming of these techniques arising from discontinuous processing would limit their practical applications.…”