Stainless 316

מה זה

Stainless 316 (often A4 in fastener talk) is an austenitic stainless steel grade with molybdenum, marketed for better chloride resistance than basic 304 in many marine fittings.

Anchor

FairHelm meets 316 claims on chainplates, fasteners, and pulpits across Baltic fleets. Crevice attack under tape, bedding, and stagnant bilge water still appears in cold winters.

FairHelm judgment

FairHelm judgment: brown weeping at sealed joints and cracked welds beat a catalogue grade. Magnet tests and stamps are clues, not a full materials lab.

Limits

We do not invent guaranteed years in seawater. Grade, surface finish, oxygen access, and load decide life.

שאלות נפוצות

Q: Is 316 immune to rust?
A: No. Crevice and weld issues still happen in marine service.

Q: Does a magnet prove it is not 316?
A: Not reliably. Work hardening and duplex alloys confuse simple magnet checks.

Q: Should every underwater fastener be 316?
A: Match duty and design. Some underwater systems use bronze or composites instead.

ליד

• Bronze seacock
• Standing rigging
• Chainplate
• Survey checklist
• Pre-purchase survey service