Two stainless families cover almost every corrosion-resistant bearing: 440C, which is hardenable and carries load, and 316, which resists almost everything but carries very little.
| Hardenable stainless | 440C — 58–60 HRC, magnetic |
|---|---|
| Non-hardenable stainless | 316 — 25–30 HRC, essentially non-magnetic |
| Salt spray, 440C | Resists fresh water and food; pits in chlorides |
| Salt spray, 316 | Resists seawater and most acids; low load only |
| Price vs 52100 | 440C ≈ 3× · 316 ≈ 3–4× |
Stainless is not one property but a family of trade-offs. 440C buys corrosion with chromium and pays for it with a slightly lower fatigue limit and a much higher price; 316 buys near-universal chemical resistance by giving up hardness entirely, which means it can only be used where the load is modest and the speed is low.
A common field failure is specifying 440C for a seawater washdown line because 'it is stainless'. 440C is martensitic and pits in chloride once the passive layer breaks down at a scratch or under a deposit. In that duty the correct choices are 316, a zirconia ceramic, or a 52100 bearing with a proper housing seal and re-lubrication interval.
Martensitic, 58–60 HRC, 250 °C — the workhorse corrosion-resistant bearing steel.
Read →Austenitic, 25–30 HRC, 300 °C — maximum chemical resistance, minimum load.
Read →Contact seals and what they do to torque and speed.
Read →Yes. Martensitic stainless is ferromagnetic, which matters for sensor-triggered positions and for any application where a magnetic bearing or a magnetic particle trap is nearby.
Speed is not the limit — load and stiffness are. 316 races are soft, so the bearing deflects more under load and the fatigue rating is low. Keep the P/C ratio well below the steel equivalent and expect a shorter life at shock loads.
The bearing itself is usually behind a seal; what matters for food contact is the lubricant (NSF H1) and the housing washdown. 440C with an H1 grease is the standard combination for food machinery.
Model numbers, quantities and the application — we reply with brand options, price and lead time within 30 minutes on working days.