Grade 316L stainless steel

Grade 316L is an austenitic stainless steel with low carbon content (the L = low, meaning carbon held to 0.03% maximum, compared with up to 0.08% in standard Grade 316). The low carbon makes it both more weldable (less risk of carbide precipitation at the weld, which can cause intergranular corrosion in 316) and more corrosion-resistant in chloride-rich environments such as breaking-surf coastal zones.

Where it shows up in residential construction

The two builder-facing uses on Australian residential jobs:

• Wall ties within 1 km of breaking surf (corrosion class R4 under AS 3700 and AS 4773 for masonry). See wall ties, where 316L is the required tie material for severe coastal exposure.
• Welded stainless fixings in marine exposure, including stainless mesh termite barriers near saltwater, pool and aquatic-centre fittings, and any welded stainless lasting decades within the salt-spray zone.

Inland and at moderate coastal distances (1 to 10 km from surf), the lower-cost 304L stainless is typically used; 316L kicks in close to the surf where chloride attack is severe.

316L vs 316

Both are the same base austenitic stainless alloy (around 16-18% chromium, 10-14% nickel, 2-3% molybdenum); the difference is carbon content and what it means in service:

• 316: carbon up to 0.08%. Fine for non-welded marine applications; risk of “sensitisation” at weld zones, where chromium carbides form and locally deplete the corrosion-resistant chromium.
• 316L (low): carbon up to 0.03%. The low carbon means the weld zone keeps its corrosion resistance, so 316L is the default where welding is involved or where conditions are severe enough that even a small loss of chromium at the weld matters.

For most fabricated stainless components on a residential build (wall ties, brackets, mesh, fixings), 316L is the safer specification in coastal contexts: a marginal cost premium for a meaningful corrosion-resistance margin.

Why it matters

Specifying plain 316 (or worse, 304) on coastal wall ties or fixings, then welding or installing them inside the breaking-surf zone, sets up a corrosion failure that shows up years after handover as rust streaks down the brickwork, lifted ties, or failed fixings in salt-spray exposure. The premium for 316L over 304L is a small line item; the cost of remediating a corroded coastal masonry wall is not.

Also known as: 316L stainless, low-carbon 316, marine-grade L stainless.

Category: Materials / metals

Related

• Wall ties, where 316L is required within 1 km of breaking surf
• AS 3700 masonry structures
• AS 4773 masonry in small buildings

See also

• BAL (bushfire attack level), the analogous bushfire severity rating that drives stainless selection elsewhere

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Last updated: 2026-05-29. Verified: 2026-05-29. Quarterly review for currency.