A clean process pump is the easiest life a bearing will ever have — as long as the pumped fluid stays in the pipe. Pumps & Compressors duty is continuous running, thrust reversal and process fluid along the shaft; the material is what decides whether the bearing survives it.
| Industry duty | continuous radial load plus axial thrust that reverses on start-up |
|---|---|
| Typical media | water, process fluid, washdown, solvent |
| Housing temperature | −20 to +150 °C |
| Material and grade | through-hardened chrome steel — 100Cr6 / 52100 |
| Hardness | 59–65 HRC |
| Temperature ceiling | 120 °C (200 °C stabilised) |
| Corrosion / chemical | none — rusts without protection |
| Relative cost | 1.0× of a standard 52100 bearing |
A process pump is a two-position arrangement: one bearing locates the shaft and takes the hydraulic thrust, the other floats and carries radial load only. Both see continuous duty at moderate temperature, which is exactly what through-hardened chrome steel is for. The two failure routes are thrust reversal at shut-off and fluid creeping along the shaft past a worn seal, and neither is solved by changing the steel.
| Position | Bearing type | Material / finish | Why it works there |
|---|---|---|---|
| Locating position (drive end) | Angular contact ball | 52100, 73xx pair, DB, preload set | Takes the hydraulic thrust and fixes the shaft position. |
| Floating position (wet end) | Cylindrical roller | 52100, NU type, C3 | Carries radial load only and slides axially as the shaft grows. |
| Small close-coupled pump | Deep groove ball | 52100, C3, 2RS | Both positions in one sealed bearing. |
| Vertical sump pump | Thrust | 52100, 51/52/53 series | Carries the whole rotor weight plus thrust. |
| Material | Fit here | Choose it when |
|---|---|---|
| 100Cr6 / 52100 | Best fit | Clean fluid, housing below 120 °C. The default for a reason. |
| 440C | Workable alternative | Washdown, food or light chemical service where moisture reaches the housing. |
| Bronze | Workable alternative | Slurry or dirty service at low speed, where conformability matters more than fatigue life. |
It is closest to the seal. When the seal wears, the fluid reaches the grease, and the bearing fails by corrosion or grease breakdown long before its rating life.
Yes, if the housing runs above 80 °C or the shaft is heated by the fluid. Without it, the bearing runs preloaded and the grease cooks.
On small close-coupled pumps, yes — a single deep groove bearing takes radial and modest axial load. Above about 5 kW the thrust needs its own locating bearing.
Hardness, temperature, corrosion and equivalents for 52100 chrome steel.
Read →Typical duty, recommended types and suffixes for pumps.
Read →Washdown & food pumps — food, beverage and CIP-washdown pumps where water reaches the bearing housing.
Read →Chemical & seawater — chemical process, seawater and brine pumps where 440C would pit.
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.