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

Disclosed is a hot-rolled steel sheet including, by mass %, C:0.02% to 0.5% of C, and the sum of the content of Si and the content of Al is 1.0% to 4.0%. An average pole density of an orientation group from {100} to {223} is 1.0 to 6.5, and a pole density of a crystal orientation {332} is 1.0 to 5.0. A microstructure includes, by of an area ratio, 2% to 30% of retained austenite, 20% to 50% of ferrite, and 10% to 60% of bainite. rC that is a Lankford value in a direction orthogonal to a rolling direction is 0.70 to 1.10, and r30 that is a Lankford value in a direction forming an angle of 30° with the rolling direction is 0.70 to 1.10.

Hot-rolled steel sheet and production method thereof

PROBLEM TO BE SOLVED: To provide a high strength galvanized steel sheet in which the generation of unplating is suppressed, and which has excellent appearance and workability, and to provide a production method therefor. SOLUTION: The high strength galvanized steel sheet having excellent workability has a composition containing, by mass, 0.0001 to 0.3% C, 0.1 to 2.5% Si, 0.01 to 3% Mn and 0.001 to 4% Al, and the balance Fe with inevitable impurities. The surface of the steel sheet is provided with a plated layer having a composition containing 0.001 to 0.5% Al and 0.001 to 2% Mn, and the balance Zn with inevitable impurities. The Si content in the steel: X (mass%), the Mn content in the steel: Y (mass%), the Al content in the steel: Z (mass%), the Al content in the plated layer: A (mass%) and the Mn content in the plated layer: B (mass%) satisfy 3-(X+Y/10+Z/3)-12.5×(A-B)≥0. COPYRIGHT: (C)2003,JPO

High strength galvanized steel sheet having excellent workability and production method therefor

PROBLEM TO BE SOLVED: To attain a high-strength steel sheet superior in workability on an industrial scale, and to provide a method for manufacturing the same on the industrial scale. SOLUTION: The high-strength steel sheet includes, by mass%, 0.07-0.20% C, 0.005-1.5% Si, 1.0-3.1% Mn, 0.001-0.06% P, 0.001-0.01% S, 0.0005-0.01% N, 0.005-1.2% Al and the balance Fe with unavoidable impurities; further has such mass% of C and Mn and a target strength value (TS) as to satisfy expression (A), wherein [TS target value] is a designed strength value of the steel sheet and the unit is MPa; [Mn] is mass% of Mn; and [C] is mass% of C; and has such a hardness distribution as to satisfy expression (B). The manufacturing method includes an annealing step in which in the first heating zone, such a temperature T1 as to satisfy expression (C) is kept for 30 seconds or longer, wherein T1 is temperature (°C); [Mn] is mass% of Mn; [Si] is mass% of Si; [Ti] is mass% of Ti; [Nb] is mass% of Nb; and [Mo] is mass% of Mo; and in a cooling zone after soaking treatment in the annealing step, a cooling rate V1 in such a period that the temperature of the steel sheet is in a range of 800-400°C and a cooling rate V2 is such a period that the temperature is lower than 400°C satisfy expression (D), wherein V1 is a cooling rate m/s in a former stage; and V2 is a cooling rate m/s in a latter stage. The high-strength steel sheet also has a metallographic structure containing ferrite and martensite. COPYRIGHT: (C)2011,JPO&INPIT

High-strength steel sheet superior in workability and method for manufacturing the same

PURPOSE:To obtain an inexpensive metal honeycomb for a catalyst by a simple joining method by doing mutual diffusion joining or liquid phase joining of a flat plate and a corrugated plate consisting of ferrite stainless steel foil having specified Mo and forming a coating film of chrome oxide at high temp. CONSTITUTION:A flat plate and a corrugated plate consisting of ferrite stainless steel foil contg. 0.3-3% Mo and on which surface a coating film comprising primarily chrome oxide is formed at high temp. are subjected to mutual diffusion joining or liquid phase joining, allowing a metal honeycomb for a catalyst to be constituted. For example, in a honeycomb body housed in an outer cylinder 1, a diffusion stop material consisting essentially of titania is applied to a shadowed portion 3 when the honeycomb body is wound to prevent the diffusion joining from occurring. The part 2 indicated by a dotted line is the area to be joined. In this way, a foil material of low manufacturing cost is used, the joining is accelerated and oxidation resistance is secured, and also an assembling process is simplified to attain cost reduction.

Metal honeycomb for catalyst

PROBLEM TO BE SOLVED: To provide a steel sheet having a developed {112} orientation and specialized for a Young's modulus in a direction perpendicular to the direction of rolling, by performing non-recrystallization annealing treatment in a low temperature region after cold rolling to form a steel sheet structure of non-recrystallized ferrite.SOLUTION: A steel sheet excellent in Young's modulus in the direction perpendicular to the direction of rolling has a composition composed of, by mass, C: 0.0007% or more and 0.05% or less, Si: 1.0% or less, Mn: 1.5% or less, P: 0.15% or less, S: 0.03% or less, Al: 0.005% or more and 0.2% or less, N: 0.007% or less, and the balance: Fe and inevitable impurities. In the steel sheet, a pole density in the {112} orientation in a 1/4 sheet thickness layer is 5.0 or greater, and an average value of an X-ray random intensity ratio in orientations other than the {112} orientation among {100} to {223} orientation groups is less than 4.0.

Nobuhiro Fujita

Papers

Hot-rolled steel sheet and production method thereof

High strength galvanized steel sheet having excellent workability and production method therefor

High-strength steel sheet superior in workability and method for manufacturing the same

Metal honeycomb for catalyst

Steel sheet excellent in young's modulus in direction perpendicular to direction of rolling and method for producing the same