| Molybdenum content | Usually not intentionally added; typically less than 0.75% | Approximately 2–3% | Molybdenum improves resistance to localized corrosion, especially pitting, in chloride-containing conditions. |
| Chromium content | Approximately 18–20% | Approximately 16–18% | Chromium forms the passive surface film that gives stainless steel its basic corrosion resistance. |
| Nickel content | Approximately 8–10.5% | Approximately 10–14% | Nickel helps maintain the austenitic structure and supports ductility and formability. |
| Suitable exposure | Interior areas, dry locations, and general-purpose environments with limited salt exposure | Coastal areas, marine-influenced locations, humid exterior doors, and areas exposed to de-icing salts | Choose 316 when chlorides may remain on the hinge surface or collect around joints and fasteners. |
| Resistance to chloride pitting | Moderate; performance decreases as chloride concentration, humidity, and surface contamination increase | Higher than 304 because of the molybdenum addition, although it is not immune to corrosion | Improved pitting resistance helps protect hinge leaves, knuckles, pins, and concealed crevices. |
| Typical indoor application | Office doors, interior commercial doors, residential interior doors, and clean indoor areas | Wet rooms, washdown areas, healthcare environments, and interior locations with frequent cleaning chemicals or salt contamination | The correct grade depends on moisture, cleaning practice, airborne contaminants, and maintenance access. |
| Typical exterior application | Sheltered exterior doors in low-salt, non-marine environments | Unsheltered exterior doors, seaside environments, docks, pools, and locations exposed to road salt | 316 generally provides a wider corrosion-resistance margin where salt spray or chloride deposits are expected. |
| Surface finish | Smooth, clean, and polished or fine-brushed surfaces improve cleanability and corrosion performance | The same finish principles apply; a smooth, properly passivated surface is preferred for chloride exposure | Grade alone is not sufficient; rough surfaces, iron contamination, scratches, and crevices can accelerate staining. |
| Maintenance requirement | Clean periodically with fresh water and a mild detergent; remove salt and chemical deposits promptly | Also requires cleaning; improved chloride resistance does not eliminate maintenance | Regular cleaning prevents deposits from concentrating in hinge gaps and around pin areas. |
| Selection recommendation | Use where corrosion exposure is controlled and cost efficiency is important | Use when chloride exposure, outdoor humidity, or frequent wet cleaning creates a higher corrosion risk | For uncertain or severe chloride exposure, 316 is usually the safer material choice, subject to the required load rating and installation details. |