Effects of Magnetic Field and Deformation on Isothermal Martensitic Transformation in SUS304 and SUS304L Steels

Abstract

Effects of external fields, such as temperature, magnetic field, stress and combination of these fields have been examined on martensitic transformation of SUS304 and SUS304L austenitic stainless steels.

Time-Temperature-Transformation Diagram of Successive γ→ε′→α′ Martensitic Transformation in SUS304L Stainless Steel

“…0 martensitic transformation proceeded by isothermal holding. 7,8) As far as the authors are aware, this was the first finding of isothermal successive ! " 0 !…”

“…That is, f 0 ¼ M 0 ðT R Þ=M 0 0 ðT R Þ, where M 0 ðT R Þ and M 0 0 ðT R Þ are the spontaneous magnetization of the specimen and that of the 0 -phase, respectively, at T R . 8) Here, the magnetizations of -phase and " 0 -martensite are neglected because they are nonmagnetic. 9,10) The value of M 0 0 ðT R Þ is approximated to be the value at 0 K, M 0 0 ð0Þ, although it is a rough approximation.…”

“…Incidentally, the Néel temperature (indicated by T N ) of the residual -phase also agrees with previous report. 7,8) Next, the time evolution of 0 -martensite during isothermal holding at 103 K has been examined by magnetization measurement under a low magnetic field of 80 kA/m, and the result is shown in Fig. 2.…”

“…0 martensitic transformation occurs in the present specimen, being in good agreement with previous studies. 7,8) The isothermal kinetics of the successive martensitic transforma- * Graduate Student, Osaka University tion is due to the ! " 0 martensitic transformation, and there is no direct !…”

Isothermal Martensitic Transformation in Sensitized SUS304 Austenitic Stainless Steel at Cryogenic Temperature

“…[11][12][13][14] Recently, we found that the sensitized SUS304 stainless steel exhibits an isothermal martensitic transformation at cryogenic temperatures. 15,16) However, its time-temperature-transformation (TTT) diagram, which is one of the most important information for isothermal transformations, has not been constructed yet.…”