This article presents an overview of the developments in stainless steels made since the 1990s. Some of the new applications that involve the use of stainless steel are also introduced. A brief introduction to the various classes of stainless steels, their precipitate phases and the status quo of their production around the globe is given first. The advances in a variety of subject areas that have been made recently will then be presented. These recent advances include (1) new findings on the various precipitate phases (the new J phase, new orientation relationships, new phase diagram for the Fe–Cr system, etc.); (2) new suggestions for the prevention/mitigation of the different problems and new methods for their detection/measurement and (3) new techniques for surface/bulk property enhancement (such as laser shot peening, grain boundary engineering and grain refinement). Recent developments in topics like phase prediction, stacking fault energy, superplasticity, metadynamic recrystallisation and the calculation of mechanical properties are introduced, too. In the end of this article, several new applications that involve the use of stainless steels are presented. Some of these are the use of austenitic stainless steels for signature authentication (magnetic recording), the utilisation of the cryogenic magnetic transition of the sigma phase for hot spot detection (the Sigmaplugs), the new Pt-enhanced radiopaque stainless steel (PERSS) coronary stents and stainless steel stents that may be used for magnetic drug targeting. Besides recent developments in conventional stainless steels, those in the high-nitrogen, low-Ni (or Ni-free) varieties are also introduced. These recent developments include new methods for attaining very high nitrogen contents, new guidelines for alloy design, the merits/demerits associated with high nitrogen contents, etc.

Recent developments in stainless steels

The present invention provides a heterocyclic compound and an organic light-emitting device including the heterocyclic compound. The organic light-emitting devices using the heterocyclic compounds have high-efficiency, low driving voltage, high luminance and long lifespan.

Organic light-emitting device

Gibbs-Thomson effects in phase transformations

A new model for the evolution of the precipitate structure derived by means of application of the thermodynamic extremum principle is presented. The model describes the evolution of the radii and of the chemical composition of individual precipitates of different phases in the multi-component system. In connection with a proper theory of nucleation, the model is able to describe the evolution of the precipitate structure in the classical stages of nucleation, growth and coarsening as well as interaction of precipitates of different phases, of different chemical composition and of different sizes via diffusion in the matrix.

Modelling of kinetics in multi-component multi-phase systems with spherical precipitates I. – Theory

Development of high strength ferritic steel for interconnect application in SOFCs

PROBLEM TO BE SOLVED: To provide a high-strength cold rolled steel sheet excellent in deep drawability, and to provide a method of manufacturing the same.SOLUTION: The high-strength cold rolled steel sheet excellent in deep drawability is characterized in that: it contains, by mass%, 0.03-0.25% C, 0.001-3.0% Si, 0.5-3.0% Mn, 0.001-0.15% P, 0.0005-0.05% S, 0.01-1.0% Al, 0.1-3.0% Cr, 0.0005-0.01% N, and the balance Fe with inevitable impurities; a mother phase is a ferrite phase; other metallographic structure contains one or two or more kinds out of bainite, austenite, martensite, pearlite in volume fraction of 2% or more; X-ray random intensity ratios of sheet faces {111} and {100} at a thickness of 1/2 in the steel sheet are respectively 5.0 or higher, and 3.0 or lower; and an average r value is 1.3 or higher.

High-strength cold rolled steel sheet excellent in deep drawability, method of manufacturing the same

Effect of Microstructure on Creep Fatigue Properties for Type 316 Austenitic Stainless Steels

PROBLEM TO BE SOLVED: To provide a high strength and high ductility galvanized steel plate excellent in workability, and a method for manufacturing the same SOLUTION: The high strength and high ductility galvanized steel plate excellent in workability, contains, by mass, 00001-03% C, 0001- COPYRIGHT: (C)2004,JPO&NCIPI

High strength and high ductility galvanized sheet plate excellent in workability, and method for manufacturing the same

PROBLEM TO BE SOLVED: To provide a working method where, in a thin steel sheet having the tensile strength of ≥590 MPa, the crack resistance of the end parts worked by blanking or cutting is improved, to provide a high strength thin steel sheet, and to provide a component composed thereof SOLUTION: In the working method for a high strength steel thin sheet having excellent crack resistance, when a thin steel sheet having the tensile strength of ≥590 MPa is subjected to blanking or cutting, using a cutting blade having a level difference part which is continuously reduced by 001 to 30 mm than the radius of curvature or width of the blade heel from the blade heel toward the direction of the end parts in the blade edge, and whose height lies within the range of 1/2 of the sheet thickness in the tin steel sheet to 100 nm, the blanking or cutting is performed By this working method, the high strength steel thin sheet in which the residual stress in the end faces worked by blanking or cutting is the tensile stress of ≤500 MPa or the residual stress of compression can be obtained COPYRIGHT: (C)2007,JPO&INPIT

Method for working high strength steel thin sheet having excellent crack resistance, and cutting blade for cutting

Synopsis : Niobium is used as an important alloying element in the design of heat-resistant ferritic stainless steels for automotive exhaust systems. When in solid solution, the niobium improves both the high temperature strength and the resistance to thermal fatigue. However, it also forms several kinds of precipitates during service at elevated temperatures, making it important to understand the kinetics of its precipitation and coarsening. In the present work, the kinetics of simultaneous reactions of niobium precipitates in ferrite have been modelled, taking into account the multicomponent nature of the diffusion process whilst at the same time allowing for capillarity effects. The model can predict not only volume fraction changes but also particle size. The experimental results on Fe2Nb Laves phase and Fe3Nb3C carbide in a 19Cr-0.8Nb steel have been obtained and shown to be comparable to be the calculations with new simultaneous model.

https://www.jstage.jst.go.jp/article/tetsutohagane1955/89/5/89_5_510/_pdf

Nobuhiro Fujita

Papers

High-strength cold rolled steel sheet excellent in deep drawability, method of manufacturing the same

Effect of Microstructure on Creep Fatigue Properties for Type 316 Austenitic Stainless Steels

High strength and high ductility galvanized sheet plate excellent in workability, and method for manufacturing the same

Method for working high strength steel thin sheet having excellent crack resistance, and cutting blade for cutting

Modelling Simultaneous Reactions of Niobium Precipitates in Ferritic Stainless Steels