18/8 Stainless Steel — Composition Check The designation “18/8 stainless steel” refers to which composition?

Introduction / Context:Shorthand notations like “18/8” are common in stainless steel practice. They concisely communicate the principal alloying elements that define phase stability, corrosion resistance, and mechanical performance for austenitic grades such as AISI 304.

Given Data / Assumptions:

• “18/8” is a compositional shorthand, not a grade specification including carbon and minor elements.
• Room-temperature austenitic structure is intended.
• Corrosion resistance primarily derives from chromium content.

Concept / Approach:“18/8” denotes approximately 18% chromium and 8% nickel. Chromium enables the passive oxide film responsible for corrosion resistance; nickel stabilises the austenitic FCC structure and improves toughness and formability. Carbon is kept low in modern “L” variants to resist sensitisation during welding.

Step-by-Step Solution:Interpret “18/8” literally → 18% Cr, 8% Ni.Cross-check with common austenitic grade AISI 304.Select the option that matches this composition.

Verification / Alternative check:Material datasheets and textbooks consistently identify 18/8 as ~18% Cr, 8% Ni.

Why Other Options Are Wrong:Swapped or doubled values do not represent the standard austenitic composition implied by “18/8.”

Common Pitfalls:Assuming 18/8 encodes carbon or molybdenum; it does not.

Final Answer:18% chromium and 8% nickel