Austenitic Steel with Manganese

201

• Non magnetic*

• Low Carbon

• Main alloying element is chromium, typically 16-20%

• Nickel typically 7-13%

• Strengthens significantly during cold working

• Good weldability

• High strength and ductility

• Cannot be hardened by heat treatment

• Low stress corrosion cracking resistance

Austenitics

301, 304L, 304, 305, 320, 321, 347,

Austenitic Steel with Molybdenum

316, 316L, 316Ti, 904L

Ferritics

409, 410S, 430, 430L, 430Ti (439), 441, 444

• Magnetic

• Low Carbon

• Main alloying element is chromium, typically 10.5-17%

• Good formability

• Low cost

• Good stress corrosion cracking resistance

• Moderate ductility

• Limited corrosion resistance

• Cannot be hardened by heat treatment

Martensitics

410, 420, 431

• Can be magnetic or non magnetic

• Low Carbon

• Main alloying element is chromium, typically 12 to 15%, molybdenum (0.2-1%)

• Hardened by quenching and tempered to give improved toughness and ductility

• Less resistant to corrosion compared to Austenitic and Ferritic grades.

• Limited formability and welding capabilities

Precipitation hardening

17/4PH, 17/7PH

• Contains Aluminium or Copper

• High work hardening rates

• Very high strengths

• Better Corrosion resistance compared to martensitics

• Limited availability

• Lower corrosion resistance, formability and weldability compared to austenitics

Duplex

309, 310

• Magnetic

• Low Carbon

• Combined Austenitic-Ferritic structure

• Chromium typically 21-26%

• Nickel typically 3.5-6.5%

• Superior tensile strength in annealed condition

• Good corrosion and pitting resistance

• Lighter weight

• Lower cost due to lower Nickel content

• Cannot be hardened by heat treatment, but offers higher annealed strength levels than Ferritic or Austenitic grades

• Restricted application temperature range when compared to Austenitics