Grade-316 Stainless Steel Plaques
Grade-316 Stainless Steel Plaques
316L · ASTM A240
Grade-316 Stainless Steel Plaques
What Is GRADE 316 STAINLESS STEEL?
Our stainless steel plaques use Grade 316L marine-grade stainless steel — designated UNS S31603 under ASTM A240. The “L” designation indicates extra-low carbon content, which prevents sensitization during welding and dramatically improves corrosion resistance versus standard 316.
The defining feature of 316 over other stainless grades is its molybdenum content (2–3%). This element specifically blocks pitting corrosion caused by chloride ions — the same ions present in salt air, ocean spray, pool chemicals, and industrial atmospheres. Without molybdenum, no stainless steel can truly be called marine-grade.
Indus Metal Plaques uses 316L for clients who require the most durable, low-maintenance, vandalism-resistant plaque available — government facilities, transportation hubs, coastal infrastructure, and any environment where absolute permanence is non-negotiable.
Alloy Composition by Weight
Why 316 over 304? The addition of 2–3% molybdenum is the entire difference — and it is critical. Molybdenum creates a passive film on the steel surface that specifically resists chloride pitting. In coastal environments, 304 stainless rusts within years. Grade 316 does not.
The Aging Process
How Stainless Steel Ages Beautifully
Unlike materials that fade or degrade, bronze develops a protective patina that actually seals and preserves the metal underneath — growing more beautiful over time.
Fresh Cast
Unidirectional grain pattern. Subdued, architectural. Reduces visible fingerprints and scratches. Most popular for plaques.
1–3 Years
High-reflectivity mirror surface. Maximum visual impact. Dramatic raised-letter effect against etched background.
5–15 Years
Uniform matte texture with no directional grain. Hides minor surface imperfections. Excellent for outdoor installations.
20–50 Years
In humid environments, green verdigris begins to appear — particularly in recesses and corners. Widely considered the mark of true age and prestige.
50–100+ Years
The full green-grey patina of historic bronze — the Statue of Liberty is an example. The plaque is now fully self- sealed and effectively immortal.
Full Specifications
Technical Data
Property
Value
Alloy Designation
316L (ASTM A240 / UNS S31603)
Composition
FE 65% · CR 17% · NI 12% · MO 2.5%
Casting Method
≤0.03% (Extra-Low Carbon “L” Grade)
Pour Temperature
1,850°F (1,010°C)
Tensile Strength
37,000 psi
Density
0.318 lb/in³ (~8.8 g/cm³)
Standard Thickness
3/8 inch base field
Relief Height
Up to 3/4 inch (title letters)
Background Color
Hunter Green (RAL 6009), baked enamel
Clearcoat System
Marine-grade polyurethane, 25-yr rating
Mounting
Stainless 3/8″ anchor bolts (template incl.)
Outdoor Lifespan
100+ years documented
Warranty
Lifetime — full replacement
Note: The material specifications, alloy composition, and performance characteristics provided are for general reference only. Actual composition, mechanical properties, finishes, and aging behavior may vary based on manufacturing processes, environmental conditions, and application. Natural patina development and color changes in bronze will differ over time.
Why Choose 316 STAINLESS WINS
Seven Reasons 316 STAINLESS WINS
Unmatched LongevityMaximum Vandalism Resistance
At 217 HB Brinell hardness, Grade 316 is 3× harder than cast bronze and 5× harder than aluminum. Graffiti, scratches, and impact damage that would ruin softer metals leave 316 unmarked.
True Marine Chloride Resistance
Molybdenum content specifically prevents pitting corrosion from chloride attack — the failure mechanism of 304 stainless and lesser alloys in coastal environments. Grade 316 was designed for the ocean.
Zero Maintenance — Ever
Unlike bronze or copper, stainless steel requires no waxing, sealing, patina management, or clearcoat renewal. Wash with water. Done. For 200 years.
Institutional Prestige
Bronze signals permanence, investment, and seriousness. It communicates that the person or institution being honored deserves a lasting tribute.
Coastal Durability
Outperforms aluminum in salt-air environments. The copper alloy resists chloride corrosion that can pit and degrade aluminum alloys over time.
Intrinsic Value
Bronze contains real copper — a commodity metal with lasting value. Your investment holds material worth beyond just its commemorative function.
Vandalism Resistant
The density and hardness of cast bronze makes it extremely difficult to deface — far more resistant to graffiti and physical damage than softer materials.