316 Stainless Steel

Plain English is a quick buyer's guide. Engineer view adds the full property tables, composition and design-for-laser figures.

Overview

316 is an austenitic chromium-nickel stainless steel with 2–2.5% molybdenum added. That molybdenum is the key difference from 304: it gives much better resistance to chlorides, salt spray and pitting, so 316 is the go-to grade for marine, coastal and chemical work. It is non-magnetic, tough across a wide temperature range and welds beautifully. Where chlorides are not a concern, 304 is more economical; where you need extra weld-zone resistance, choose low-carbon 316L.

Best for

Marine and coastal parts and fittings
Food, brewing and chemical equipment
Outdoor architectural and hardware parts
Pharmaceutical and hygienic fabrications
Welded fabrications needing corrosion resistance

Less ideal for

Budget indoor parts where 304 will do
High-strength structural members (use carbon/PH grades)
Easy, fast machining (work-hardens; gummy to cut)
Strong magnetic applications (non-magnetic)

Properties

BS EN 10088-2:2014

Physical

Density	7.98	g/cm³
Melting range	1370–1400	°C
Thermal expansion	16	×10⁻⁶/K
Modulus of elasticity	200	GPa
Thermal conductivity	15	W/m·K
Electrical resistivity	0.75	µΩ·m

Mechanical

Tensile strength	520–680	MPa
Proof stress (0.2%)	220 min	MPa
Hardness	215 max	HB
Elongation A50	40 min	%

Cold-rolled sheet, annealed (typical; figures vary with form)

Chemical Composition

BS EN 10088-2 · 316 / 1.4401 (X5CrNiMo17-12-2)

Fe Cr Ni Mo Mn Si N C P S

Element		% present
Iron	Fe	Balance
Chromium	Cr	16.5 – 18.5
Nickel	Ni	10.0 – 13.0
Molybdenum	Mo	2.0 – 2.5
Manganese	Mn	0.0 – 2.0
Silicon	Si	0.0 – 1.0
Nitrogen	N	0.0 – 0.11
Carbon	C	0.0 – 0.07
Phosphorus	P	0.0 – 0.045
Sulphur	S	0.0 – 0.015

Formability & Fabrication

316 forms well cold — it bends, folds and deep-draws cleanly, though it work-hardens quickly so it needs more force than mild steel and benefits from generous radii. It welds excellently by TIG and MIG with no pre-heat. For thicker welded sections choose low-carbon 316L to avoid carbide precipitation. Machining is fair: it is tough and gummy, so use sharp tooling, slow speeds and plenty of coolant.

Cold working

Good

Bending

Good

Deep drawing

Good

Arc / TIG / MIG

Excellent

Resistance weld

Excellent

Brazing

Good

Soldering

Fair

Machinability

Fair

Recommended filler wire: 316L (ER316L) for most 316 welds, giving a colour and corrosion match; 316LSi for smoother MIG running. Use low-carbon filler on welded parts to keep the weld zone's chloride resistance.

Corrosion Resistance

The 2–2.5% molybdenum is what sets 316 apart: it gives excellent resistance to chlorides, salt spray and pitting that would attack 304, which is why 316 is the standard choice for marine, coastal and chemical service. It shrugs off most atmospheres, fresh water and food acids, and resists many chemicals well. Very hot, concentrated chlorides can still cause stress-corrosion cracking, so confirm for severe duties.

Environment	Suitability
Atmospheric / outdoor	Excellent
Marine splash / coastal air	Excellent
Fresh water	Excellent
Food & mild chemical	Excellent
Salt-water immersion	Good
Hot concentrated chlorides	Fair

Typical Applications

Marine fittings & deck hardware Food, brewing & dairy equipment Chemical & process plant parts Pharmaceutical & hygienic fabrications Coastal architectural fittings Outdoor signage & enclosures Pump, valve & pipework components Heat exchanger & tank parts

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Laser Cutting & Ordering

at Metal Parts Direct

Thicknesses we cut

0.9 mm1.2 mm1.5 mm2 mm2.5 mm3 mm4 mm5 mm6 mm8 mm10 mm12 mm15 mm20 mm

Cut tolerance

±0.25 mm up to 20 mm, ±0.5 mm above

Max part size

1000 × 1000 mm

Max part weight

No maximum

Estimated delivery if ordered today

Friday 28th August 2026 – Monday 31st August 2026

UK-made Laser cut to your spec No minimum order Material certs on request

Design-for-laser quick reference

These are the exact minimums the Part Builder enforces as you design, relative to sheet thickness — so your part and your quote never disagree.

Feature	Minimum
Min hole / bore Ø	0.7 × thickness (min 1 mm)
Min slot / opening width	0.7 × thickness (min 1 mm)
Min web / wall between cuts	0.7 × thickness (min 1 mm)
Min cut-to-edge distance	0.7 × thickness (min 1 mm)

Frequently Asked Questions

What is the difference between 316 and 304?

Both are austenitic stainless steels, but 316 adds 2–2.5% molybdenum. That gives it much better resistance to salt, chlorides and pitting, so it is the marine and chemical choice. Where chlorides are not a concern, 304 does the same job for less.

Is 316 good for marine use?

Yes — it is one of the standard marine stainless grades. The molybdenum gives excellent resistance to coastal air and salt spray, so it is widely used for boat fittings, deck hardware and seaside structures.

What is the difference between 316 and 316L?

316L is the low-carbon version (carbon held to about 0.03%). It resists carbide precipitation during welding, so it keeps its corrosion resistance in the weld zone better. For thicker or critical welded parts, 316L is preferred; for general work the two perform much the same.

Is 316 stainless steel magnetic?

In its annealed sheet form it is essentially non-magnetic, as it is an austenitic grade. Heavy cold work or forming can make it slightly magnetic in places, but it will never behave like a ferritic or carbon steel.

Will my laser-cut part be marked or scratched?

316 is tough and stands up well to handling, but it is still a polished surface that can scuff. If finish is critical, ask about PVC-film-coated sheet and handle the part carefully after cutting.

Equivalents

Also designated

EN 1.4401 AISI 316 S31600 X5CrNiMo17-12-2 UNS S31600

Cross-references are indicative and may not be exact equivalents — confirm against the certificate for critical work.

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This data is indicative and provided in good faith from recognised EN standards and industry references. It is not a substitute for the full specification or material certificate; mechanical properties in particular vary with temper, form and dimension. Material supplied will conform to the relevant applicable standards but may differ from these figures. No liability is accepted for actions taken in reliance on this guide. Confirm critical values against the certificate for your delivery.