Recrystallization Of Stainless Steel Research Articles

Recrystalization Behavior of Coldworked 14Cr-15Ni-2Mo Austenitic Stainless Steel Under Tensile Deformation

AbstractRecrystallization behavior of 20% coldworked alloy D9 (14Cr-15Ni-2Mo austenitic stainless steel) during high temperature tensile deformation has been assessed. The alloy was produced by vacuum induction melting followed either by vacuum arc refining (VAR) or electroslag refining (ESR). Tensile studies were carried out at various temperatures between ambient and 1073 K at an interval of 50 K and at strain rate of 1.2 × 10−3 s−1. The peak in the stress-strain curve was observed for the tensile tests conducted at 973–1073 K. This is attributed to dynamic recrystallization during tensile deformation. The values of the apparent activation energy were estimated as 384 kJ/mol for ESR grade alloy D9 and 372 kJ/mol for VAR grade alloy D9 by hyperbolic-sine Arrhenius equation, which agree well with that required for dynamic recrystallization in stainless steels. TEM studies confirmed extensive recovery and dynamic recrystalization in both the alloys.

The influence of helium distribution and grain size on high-temperature embrittlement of stainless steel

In order to study the high-temperature embrittlement related to helium from the viewpoint of the distribution of helium and the grain size, helium ( 7.5 × 10 −6 atomic fraction) was injected into stainless steel treated in various ways, using a cyclotron. Helium retarded the tendency towards recrystallization of stainless steel, and the grain size of the specimen recrystallized after injection was clearly smaller. The high-temperature embrittlement related to helium in stainless steel was appreciable above 650°C, and could be classified in terms of the mean grain diameter and the distribution of helium.