Material specification page for uc300 series insert bearings in Cast Iron. Covers the grade designation (grey cast iron EN-GJL-200 / EN-GJL-250 for standard housings; ductile iron EN-GJS where shock or tension is expected), what the material does inside the bearing, its temperature and environmental limits, the alternatives worth considering, and the sizes available to JIS B 1558 / ISO 9628.
Why Cast Iron for UC300 Series Insert Bearings
The housing material for pillow blocks, flange units and plummer blocks — rigid, well damped, and stable enough to hold a round, correctly sized bearing seat after machining. In a uc300 series insert bearings it is the housing that carries the bearing and bolts to the machine.
A bearing housing has to be stiff, well damped and dimensionally stable, and it has to hold a round bore after machining and after bolting down. Grey cast iron does all four cheaply, which is why almost every pillow block and plummer block is made of it.
Material Properties
| Grade designation | grey cast iron EN-GJL-200 / EN-GJL-250 for standard housings; ductile iron EN-GJS where shock or tension is expected |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | About -20 °C to +200 °C for a standard grey iron housing |
| Corrosion characteristic | Forms a stable surface oxide indoors; painted or coated for outdoor and washdown service |
Service Limits
Grey cast iron is strong in compression and weak in tension, so it does not like shock or bending — a housing dropped in transit can crack invisibly, and a bolt over-torqued into a cast foot splits it. Where shock is expected, a ductile iron or cast steel housing is the correct part. Outdoors, the surface needs paint or coating.
What the Material Changes About the Bearing
The housing does not carry the rolling contact, but it decides the fit. It has to hold the bearing seat round and to size after machining and after the feet are bolted to a base that is never perfectly flat, and it has to conduct the heat the bearing generates away into the structure. A distorted housing is a bearing running with the wrong clearance.
Sizes of UC300 Series Insert Bearings Available in Cast Iron
| Designation | Bore d (mm) | Outer diameter D (mm) | Width B (mm) |
|---|---|---|---|
| UC305 | 25 | 62 | 38.1 |
| UC306 | 30 | 72 | 42.9 |
| UC307 | 35 | 80 | 48.4 |
| UC308 | 40 | 90 | 52.4 |
| UC309 | 45 | 100 | 55.6 |
| UC310 | 50 | 110 | 65.1 |
| UC311 | 55 | 120 | 65.1 |
| UC312 | 60 | 130 | 77.8 |
| UC313 | 65 | 140 | 77.8 |
| UC314 | 70 | 150 | 82.6 |
| UC315 | 75 | 160 | 82.6 |
