In a washdown conveyor the bearing is replaced because it rusted, not because it wore out — 440C attacks that specific failure. Conveyors & Bulk Handling duty is slow speed, abrasive dust and frame misalignment; the material is what decides whether the bearing survives it.
| Industry duty | slow rotation under steady belt pull, with abrasive dust at the load point |
|---|---|
| Typical media | abrasive dust, fines, washdown water |
| Housing temperature | −20 to +90 °C |
| Material and grade | 440C martensitic stainless steel |
| Hardness | 58–60 HRC |
| Temperature ceiling | 250 °C |
| Corrosion / chemical | fresh water, food and mild chemicals; pits in chlorides |
| Relative cost | ≈3× of a standard 52100 bearing |
A food conveyor is washed down at the end of every shift with 60–80 °C water and caustic, and the bearings sit in the splash. A chrome steel race forms a rust film overnight, that film is abrasive, and the bearing wears out in a quarter. 440C keeps the hardness and most of the capacity while resisting the film, and matching stainless housings remove the rust streaks that fail an audit.
| Position | Bearing type | Material / finish | Why it works there |
|---|---|---|---|
| Head pulley, washdown | Ball bearing unit | 440C insert, stainless housing, H1 grease | Both races stainless; the housing does not stain the wash water. |
| Belt support roller | Deep groove ball | 440C, 2RS, H1 grease | A rust film on a chrome steel race is the usual cause of seizure. |
| Take-up unit | Ball bearing unit | 440C insert, 2RS | Sits in the wettest part of the frame. |
| Material | Fit here | Choose it when |
|---|---|---|
| 440C | Best fit | Caustic and water washdown at 60–80 °C, with an H1 grease. |
| 316 | Workable alternative | Chlorinated sanitiser or brine: no pitting, at half the load rating. |
| 100Cr6 / 52100 | Workable alternative | Dry or wipe-down conveyors — coating the housing is enough. |
For a food audit, usually yes. A rusting cast iron housing stains the wash water and the frame, even if the bearing itself is fine.
Roughly twice as long as 52100 in caustic wash. In hypochlorite it can be shorter, because pitting replaces rust as the failure mode.
No. Fresh grease does not remove water that has already passed the seal, and over-greasing can push the seal off its seat.
Hardness, temperature, corrosion and equivalents for 440C stainless.
Read →Typical duty, recommended types and suffixes for conveyors.
Read →Head & tail pulleys — head and tail pulley bearings and idler positions in bulk handling.
Read →Chemical & fertiliser — fertiliser, salt and chemical conveyors where chlorides are constant.
Read →Send the position, bore size, quantity and the medium it sees. We reply with the material certificate, clearance class, lubricant and price within 30 minutes on working days.