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

This invention provides a hot-rolled steel for gaseous nitrocarburizing with excellent isotropic workability, and a manufacturing method thereof. In addition to having an appropriate chemical composition, this hot-rolled steel for gaseous nitrocarburizing has, in the plate thickness center 5/8 to 3/8 of the plate thickness from the surface of the steel plate, a 1.0-4.0 average pole density of the orientation group {100} -{223} , expressed by the arithmetic average of the pole densities of each orientation of {100} , {116} , {114} , {112} and {223} , and has a 1.0-4.8 pole density of the crystal orientation {332} . This hot-rolled steel sheet further has a 10μm or smaller average crystal particle diameter in the plate thickness center, and the microstructure comprises perlite (over 6% by component percentage) and ferrite (the remaining portion).

Hot-rolled steel for gaseous nitrocarburizing and manufacturing method thereof

A metallic honeycomb body for supporting a catalyst comprises a flat plate and a corrugated plate; these plates are formed by a foil of stainless steel in which the steel contains more than 1% of Si and the surface of the steel is covered by a film which is mainly formed by an oxide chrome at a high temperature, and are mutually bonded by diffusion bonding. The chemical composition of the foil material is comprised of up to 0.2% of C, more than 1 to 5% of Si, 9 to 22% of Cr, up to 0.8% of Al, and as necessary, at least one member selected from the group of Nb, V, Mo W and REM (rare earth member) including Y. The metallic honeycomb body is formed by which said body is annealed at a vacuum degree of 10-2 to 10-4 Torr and in a temperature range of 1200° to 1300° C. for 1 to 30 minutes in a vacuum annealing furnace.

Metallic honeycomb body for supporting catalyst and production method thereof

PROBLEM TO BE SOLVED: To provide a steel sheet having a tensile strength of ≥900 MPa and having an excellent hole expansibility, and to provide its production method SOLUTION: The high strength cold rolled thin steel sheet having an excellent hole expansibility has a composition comprising, by mass, 005 to 022% C, 0001 to 08% Si, 20 to 33% Mn, 0001 to 01% P, 00001 to 001% S, 0001 to 02% Al, 00001 to 001% B and 0005 to 03% Ti, and the balance Fe with inevitable impurities, has a tensile strength of ≥1,100 MPa, and also has a hole expansion ratio of ≥40% COPYRIGHT: (C)2006,JPO&NCIPI

High strength cold rolled thin steel sheet having excellent hole expansibility and its production method

PROBLEM TO BE SOLVED: To provide a steel sheet which has a tensile strength of ≥900 MPa, and is excellent in bore expandability, and to provide its production method. SOLUTION: The hot dip galvanized high strength steel sheet having excellent bore expandability has a composition comprising, by mass, 0.03 to 0.12% C, 0.001 to 0.8% Si, 2.3 to 3.3% Mn, 0.001 to 0.1% P, 0.0001 to 0.01% S, 0.001 to 0.2% Al, 0.11 to 1.0% Mo and 0.005 to 0.3% Ti, and the balance Fe with inevitable impurities, and has a tensile strength of ≥900 MPa, a product between the bore expanding ratio λ(%) and the tensile strength TS (MPa) of ≥5×10 4 (MPa%), and a martensite single phase structure. COPYRIGHT: (C)2005,JPO&NCIPI

Hot dip galvanized high strength steel sheet having excellent bore eaxpandability, and its production method

PROBLEM TO BE SOLVED: To provide a steel pipe which controls formation of oxidized scale in diameter-reducing process at a high temperature, occurrence of plating failures at diameter-reducing process, adherence of the plated film to a diameter- reducing roll, and galling on the diameter-reducing roll by the steel pipe, and further has an adequate surface grade even after the provided steel pipe has been formed into a car component, and to provide a manufacturing method therefor and the car component using the steep pipe. SOLUTION: The aluminum plated steel pipe has an Fe-Al coating layer on the surface of the steel pipe, wherein an Al concentration in a 1-3 μm deep surface region of the Fe-Al coating layer is 3-35% by mass%, and the Al concentration in at least 1 μm thick region in the Fe-Al coating side from the interface between the Fe-Al coating layer and the iron matrix is 0.5-15% by mass%. The method for manufacturing the aluminized steel pipe is characterized by heating the steel pipe having the Al coating layer on its surface at a predetermined temperature for a fixed time, and forming it so as to have a 15% or more reduced diameter and a wall thickness changed in a ratio between minus 20% and plus 10%. COPYRIGHT: (C)2004,JPO

Nobuhiro Fujita

Papers

Hot-rolled steel for gaseous nitrocarburizing and manufacturing method thereof

Metallic honeycomb body for supporting catalyst and production method thereof

High strength cold rolled thin steel sheet having excellent hole expansibility and its production method

Hot dip galvanized high strength steel sheet having excellent bore eaxpandability, and its production method

Aluminized steel pipe, car component, and manufacturing method therefor