Home · Materials · 316 Stainless
Stainless Steel

316 Stainless

316 is the molybdenum-bearing austenitic stainless that ships when 304 isn't enough. The ~2% Mo addition sharply improves resistance to chlorides and pitting, earning it the corrosion 5/5 rating and a home in marine, medical, and chemical service. Strength is modest (240 MPa yield) but ductility is high at 40% elongation.

How 316 Stainless machines

Rated 2.5/5, and it earns it. Like all austenitics, 316 work-hardens fast: dwelling or rubbing glazes the surface and ruins the next pass. Keep tools sharp, feeds positive, and never let the cutter stop in the cut. Use rigid setups, flood coolant, and sharp coated carbide. Expect built-up edge and stringy chips.

Manufacturing & processing

Suits CNC machining and sheet metal forming. Readily welded (TIG/MIG) with 316L preferred to dodge sensitization; the low-carbon grade resists chromium-carbide precipitation at weld zones. No heat-treat hardening, austenitic; it's strengthened only by cold work. Passivate after machining to restore the chromium oxide film. Excellent finish potential.

Typical applications

Marine hardware, boat fittings, and railings exposed to salt spray; surgical and implantable medical components; pharmaceutical and food-processing equipment; chemical tanks, valves, and piping handling chlorides or acids; coastal architectural trim. Chosen wherever 304 would pit in chloride-rich environments.

When to choose it

Choose 316 when the part sees saltwater, chlorides, or aggressive chemicals and 304 would pit, or when medical/pharma cleanliness is required. If exposure is only mild atmospheric or freshwater, 304 saves cost. If you need easy machining over corrosion, step to 303.

Suitable surface finishes

Common finishes for 316 Stainless: passivation, electropolishing, bead blasting, brushed. Use the finish selector →

FAQ

What's the real difference between 316 and 304?
316 adds roughly 2% molybdenum, which dramatically improves resistance to chloride pitting and crevice corrosion. That's why 316 rates 5/5 corrosion versus 304's 4.5. For saltwater, de-icing salts, or chloride process streams, 316 is worth the cost premium; for general use, 304 suffices.
Why does 316 machine so slowly?
As an austenitic stainless it work-hardens aggressively and has low thermal conductivity (16 W/m·K), so heat stays at the cutting edge. Rubbing or light dwelling instantly hardens the surface. Sustained feed, sharp tools, and flood coolant are mandatory; expect roughly 40-50% of mild-steel cutting speeds.
Should I specify 316 or 316L for welded parts?
Specify 316L for anything welded. The lower carbon content prevents chromium-carbide precipitation at grain boundaries in the heat-affected zone, which would otherwise sensitize the steel and cause intergranular corrosion. For machined-only parts not subjected to welding, standard 316 is fine.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.