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 steel pipe which suppresses the formation of oxide scale in diameter reduction compression working at a high temperature and suppresses the occurrence of a plating defect during the diameter reduction working, the adhesion of the plating to diameter reduction rolls and the galling, etc., of the steel pipe to the diameter reduction rolls, a method for manufacturing the same and automotive parts using such steel pipe. SOLUTION: The aluminum plated steel pipe having the excellent workability, corrosion resistance and heat resistance is characterized in that the steel pipe has an Fe-Al coating on its surface and that the Al concentration of the Fe-Al coating is 5 to 70% by mass %. The method for manufacturing the aluminum plated steel pipe having the excellent workability, corrosion resistance and heat resistance comprises heating the steel pipe having the Al coating on the surface to 800 to 1,200°C and subjecting the steel pipe to working by which a diameter reduction of ≥15% and a board thickness change rate of -20 to +10% are attained. COPYRIGHT: (C)2004,JPO

Aluminum plated steel pipe having excellent workability, corrosion resistance and heat resistance and automotive parts

The present invention provides a steel pipe excellent in formability during hydraulic forming and the like and a method to produce the same, and more specifically: a steel pipe excellent in formability having an r-value of 1.4 or larger in the axial direction of the steel pipe, and the property that the average of the ratios of the X-ray intensity in the orientation component group of a110u to a332u on the plane at the center of the steel pipe wall thickness to the random X-ray intensity is 3.5 or larger, and/or the ratio of the X-ray intensity in the orientation component of a110u on the plane at the center of the steel pipe wall thickness to the random X-ray intensity is 5.0 or larger; and a method to produce a steel pipe excellent in formability characterized by heating the steel pipe having the property that the ratio of the X-ray intensity in every one of the orientation components of a001u , a116u , a114u and a112u on the plane at the center of the mother pipe wall thickness to the random X-ray intensity is 3 or smaller to a temperature in the range from 650 to 1,200 DEG C and by applying working under a condition of a diameter reduction ratio of 30% or more and a wall thickness reduction ratio of 5 to 30%.

Steel pipe with good formable character and producing method thereof

PROBLEM TO BE SOLVED: To provided a method of accurately determining bending limitation of a plate material and a method of accurately determining a crack of a pressed component caused by bending using the same. SOLUTION: The method of determining bending limitation of a plate material includes a step of bending the plate material with a thickness of t using a V-shaped punch 1 and V-shaped die 2 to determine the bending limitation of the plate material based on the presence of a crack, wherein an apex R of the V-shaped punch is changed in a range of 0.1 COPYRIGHT: (C)2011,JPO&INPIT

Method of determining bending limitation of plate material and method of determining crack of pressed component by bending using the same

PROBLEM TO BE SOLVED: To provide a ferritic stainless steel for automobile exhaust system equipment, capable of production at low finish annealing temp. and excellent in cold formability and high temp. strength. SOLUTION: The ferritic stainless steel, which has a composition consisting of, by mass, <=0.005% C, <=0.008% N, <=0.45% Si, <=1% Mn, 10-12.5% Cr, 0.05-0.3% Nb, 8×(C+N) to 0.3% Ti, and the balance Fe with inevitable impurities and satisfying C+N<=0.009%, is prepared.

Ferritic stainless steel for automobile exhaust system equipment

This high-strength cold-rolled steel sheet having excellent uniform elongation and hole expandability contains, C: 001 to 04%; Si: 0001 to 25%; Mn: 0001 to 40%; P: 0001 to 015%; S: 00005 to 003%; Al: 0001 to 20%; N: 00005 to 001%; and O: 00005 to 001%; in which Si+Al is limited to less than 10%, and a balance being composed of iron and inevitable impurities, in which at a sheet thickness center portion, an average value of pole densities of the {100} to {223} orientation group is 50 or less, and a pole density of the {332} crystal orientation is 40 or less, a metal structure contains 5 to 80% of ferrite, 5 to 80% of bainite, and 1% or less of martensite in terms of an area ratio and the total of martensite, pearlite, and retained austenite is 5% or less, and an r value (rC) in a direction perpendicular to a rolling direction is 070 or more and an r value (r30) in a direction 30° from the rolling direction is 110 or less

Nobuhiro Fujita

Papers

Aluminum plated steel pipe having excellent workability, corrosion resistance and heat resistance and automotive parts

Steel pipe with good formable character and producing method thereof

Method of determining bending limitation of plate material and method of determining crack of pressed component by bending using the same

Ferritic stainless steel for automobile exhaust system equipment

High-strength cold-rolled steel sheet having excellent uniform elongation and hole expandability