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

Multi-scale characterization of stress corrosion cracking of cold-worked stainless steels and the influence of Cr content

The structure and composition of surface oxide films on austenitic stainless steels in hydrogenated high-temperature water were examined by changing the chromium content in alloys and the concentration of dissolved hydrogen in high-temperature water. Auger electron spectroscopy, X-ray diffraction and analytical transmission electron microscopy revealed that the oxide films had a double-layer structure: ironbased spinels as the outer layer and chromium-rich spinel oxide as the inner layer. Increasing the chromium content suppressed the corrosion rate and produced fine oxide particles with a higher chromium concentration in the inner layer. Increasing the concentration of dissolved hydrogen enhanced the corrosion rate without a notable change in oxide structure. These influences are considered to originate from changes in cation diffusion through the inner layer, such as a decrease in the lattice diffusion of iron in the inner layer due to a higher concentration of chromium in the oxide as a diffusion barri...

https://www.tandfonline.com/doi/pdf/10.1080/18811248.2008.9711883

Corrosion Behavior of Stainless Steels in Simulated PWR Primary Water—Effect of Chromium Content in Alloys and Dissolved Hydrogen—

The role of cold work and applied stress on surface oxidation of 304 stainless steel

Atom probe tomography today

The influence of material factors on the intergranular stress corrosion cracking (IGSCC) susceptibility of austenitic stainless steels under hydrogenated high-temperature water were studie...

Intergranular Stress Corrosion Cracking Behavior of Austenitic Stainless Steels in Hydrogenated High-Temperature Water

The purpose of this work is to understand quantitative processes which underlie the initiation of stress corrosion cracking (SCC) of cold-worked, thermally treated Alloy 690 after long-term exposures in high-temperature water. Long-term stress corrosion cracking initiation tests up to 34,484 h have been performed on cold-worked, thermally treated Alloy 690 under static load conditions using 0.5T compact tension specimens with a shallow depth of the precrack (0.1 mm to approximately 0.3 mm) and blunt notch compact tension type specimens. These specimens were exposed in the primary coolant environments of pressurized water reactors under static load conditions both at 320°C and 360°C. Three important patterns were observed. First, intergranular cracking observed from the shallow precracks after 21,838 h at 320°C and 20,653 h at 360°C, respectively, in 20% cold-worked Alloy TT690 in primary water. Second, clear evidence of cavities were identified ahead of the SCC-tip after the tests both at 360°C and 320°C....

Degradation of Alloy 690 After Relatively Short Times

Plant life extension from the initial licensed life to beyond 60 years is now being discussed for light water cooled nuclear powered reactors (LWRs). Reliable prediction for material degradation is...

Role of Cavity Formation on Long-Term Stress Corrosion Cracking Initiation: A Review

Crack growth behavior of welded and cast stainless steels in hydrogenated and oxygenated high-temperature water

The primary purpose of this research is to examine the stress corrosion cracking (SCC) resistance of Alloy 800NG in pressurized water reactor (PWR) primary water and pressurized heavy water reactor (PHWR) primary water. Rates of SCC growth of 20% cold-worked (CW) Alloy 800NG measured over the temperature range between 270°C and 360°C were compared with previously reported results for 20% CW Alloy TT690 and 20% CW Alloy 600 in order to consider which material is the most SCC resistant among materials presently being used for steam generator (SG) tubing worldwide. The secondary purpose is to examine the effect of chromium addition on SCC growth in PWR primary water of a series of alloys based on the Alloy 800 composition. SCC growth measurements were performed in PWR primary water over the chromium concentration range from 16% to 27% to obtain fundamental knowledge useful for considering a future alternative SCC-resistant material for SG tubing in extended life PWRs and PHWRs. The third objective is to exam...

Koji Arioka

Papers

Intergranular Stress Corrosion Cracking Behavior of Austenitic Stainless Steels in Hydrogenated High-Temperature Water

Degradation of Alloy 690 After Relatively Short Times

Role of Cavity Formation on Long-Term Stress Corrosion Cracking Initiation: A Review

Crack growth behavior of welded and cast stainless steels in hydrogenated and oxygenated high-temperature water

Stress Corrosion Cracking Growth of Alloy 800NG in Pressurized Water Reactor Primary Water