Stainless Steel Nuts

Duplex stainless steels have a two-phase microstructure of austenite and ferrite grains. The duplex structure gives this family of stainless steels a combination of attractive properties:

• Strength: Duplex stainless steel is about twice as strong as regular austenitic or ferritic stainless steels.
• Toughness and ductility: Duplex stainless steel has significantly better toughness and ductility than ferritic grades; however, they do not reach the excellent values of austenitic grades.
• Corrosion resistance: As with all stainless steels, corrosion resistance depends mostly on the composition of the stainless steel. For chloride pitting and crevice corrosion resistance, their chromium, molybdenum and nitrogen content are most important. Duplex stainless steel grades have a range of corrosion resistance, similar to the range for austenitic stainless steels, i.e from Type 304 or 316 (e.g. LDX 2101©) to 6% molybdenum (e.g. SAF 2507©) stainless steels.
• Stress corrosion cracking resistance: Duplex stainless steel shows very good stress corrosion cracking (SCC) resistance, a property they have “inherited” from the ferritic side. SCC can be a problem under certain circumstances (chlorides, humidity, elevated temperature) for standard austenitics such as Types 304 and 316.