Among the main stainless steel families, which is generally non-magnetic in the annealed condition due to its face-centered cubic (FCC) structure?

Introduction / Context:Stainless steels are categorized by microstructure: ferritic (BCC), martensitic (BCT), austenitic (FCC), and duplex (mixed). Magnetic behavior correlates strongly with structure and processing condition.

Given Data / Assumptions:

• Condition: annealed (solution-treated) state.
• Family chemistries: austenitic (e.g., 304, 316) high Ni stabilizing FCC.

Concept / Approach:Austenitic stainless steels have an FCC lattice stabilized by nickel (and sometimes manganese/nitrogen). FCC austenite is generally non-magnetic. Cold work can induce partial martensite, causing slight magnetism, but the annealed baseline is essentially non-magnetic.

Step-by-Step Solution:1) Map families to structures: ferritic = BCC (magnetic), martensitic = BCT (magnetic), austenitic = FCC (non-magnetic in annealed state).2) Identify typical grades: 304/316 are non-magnetic when properly annealed.3) Conclude: austenitic is the non-magnetic family.

Verification / Alternative check:Quick shop-floor test: annealed 304 shows negligible attraction to magnets, while 430 (ferritic) and 410 (martensitic) are magnetic.

Why Other Options Are Wrong:Ferritic and martensitic are magnetic due to BCC/BCT structures.“None of these” is incorrect because austenitic is well known to be non-magnetic in annealed condition.Duplex (not in original list but included as a distractor) is ferrite+austenite and shows partial magnetism.

Common Pitfalls:Observing magnetism in cold-worked austenitic stock and assuming the family is magnetic; cold work can induce strain martensite.

Final Answer:Austenitic