An Introduction to High Performing Stainless Steels
High performing stainless steels supplied across Europe by NeoNickel offer superior corrosion resistance compared to standard stainless steel grades. They’re better able to fight pitting and stress corrosion in aggressive environments, especially ones containing the chloride ion.
This highly corrosion resistant steel is manufactured by using enhanced levels of chromium, nickel, molybdenum and nitrogen alloying. Because these grades are produced with low carbon contents they preserve their resistance and allow hot fabrication and welding.
Development of High Performing Stainless Steels
High performance stainless steel production became a commercial reality in the 1970s with the dawn of steel melting and refining technologies that meant compositions with low carbon content and tight composition control could be produced in a cost-effective way.
Technologies such as vacuum melting, electron beam remelting, electroslag remelting led the way, with vacuum oxygen decarburisation (VOD) and argo-oxygen decarburization (AOD) being the most significant today from a commercial point of view.
The financial importance of these steels has increased ever since and more varieties have been produced.
There are three main kinds of high-performance steel – austenitic, ferritic and duplex (austenitic –ferritic). Each kind has a lot in common, but the wide variations between them in terms of corrosion resistance and other characteristics means on kind – or an individual grade – can be best for a particular job.
Austenitic
The higher nickel content of austenitic stainless steel grades means they’re often chosen for severe acid service and for their resistance to chloride pitting and stress corrosion cracking. Typical uses include flue glass cleaning equipment that handles acid condensates, or where materials are exposed to acidic solutions containing strong oxidants, as in paper bleaching.
Austenitic grades are relatively easy to weld so they’re often chosen for situations such as offshore and nuclear piping where weld quality is extremely important and much of construction must be done in the field.
Ferritic
Thin sheet stainless steel is usually most cost-effective when produced from ferritic grades, so they are, for instance, used as the tube material in many kinds of heat exchangers.
Duplex
Duplex stainless steel grades are often used in situations where strength is a major consideration. They are found in pressure vessels for the chemical process industry and in heat exchangers, for example.
Each type of high performance stainless steel will offer superior resistance to chloride pitting and stress corrosion cracking to standard grades such as Type 304L (which contains only 18% chromium and 8% nickel) and Type 316L (which contains similar amounts of chromium and nickel and 2% molybdenum). Fabrication considerations are often the biggest factor in deciding which type to select.
Working with High Performance Stainless Steels
High performance steels are a sophisticated product for demanding applications. So they are more technically demanding than Types 304 and 316 in regard to metallurgy and fabrication requirements. It’s vital to have a full understanding of these stainless steels to use them well.
There are many complex applications for high performance stainless steels and a large number of grades to select from. NeoNickel’s technical staff will be delighted to discuss the advantages and limitations of individual types of high performance steel, along with their specific individual requirements, to help you make the optimal choice.
Contact us today and we’ll be able to help.
