From the blast furnace and sinter plant through continuous casting, hot rolling and cold rolling, ZBZ supplies long-life bearings and custom-engineered retrofit packages for the combined burden of high temperature, heavy load, shock loading and cooling water found across a steel works. The objective is single-minded: fewer unplanned stoppages, longer intervals between roll changes.
The great majority of premature failures are not a question of "poor bearing quality" — they happen because standard catalogue products were never designed for these combined duty conditions. ZBZ breaks the failure mechanism down first, then changes the design.
Continuous caster segment rolls and furnace-area roller tables operate permanently at 200 – 600 °C. Conventional bearing steel tempers and softens, the grease carbonises and cokes, and the bearing seizes or spalls prematurely.
The instant the mill bites the stock it produces a shock peak, and backup roll bearings carry rolling forces measured in thousands of tonnes. Concentrated contact stress readily triggers edge spalling and cage fracture.
Mill scale particles in the hot rolling area are extremely hard. Once they reach the raceway they leave indentations that become the initiation point for fatigue spalling.
The secondary cooling zone of a caster runs with heavy spray water. Once sealing is lost the grease emulsifies and washes out, and the bearing fails quickly in a starved condition.
When a line stops for a bearing failure the loss runs into five figures for every hour, and the repair window is extremely short.
The roll stack deflects under load and machining tolerances accumulate across the chocks, producing eccentric loading and a steep drop in service life.
Sinter machine pallet cars, crushers, drum mixers, belt conveyor pulleys
Charging system, skip hoist, hot blast stove valves, cast house equipment
BOF tilting mechanism (trunnion bearings), ladle turret, electric arc furnace, ladle refining furnace
Caster segment rolls, withdrawal and straightening units, dummy bar, cutting-zone roller tables
Reheating furnace rollers, roughing/finishing work rolls and backup rolls, coilers
Cold mills, temper mills, straighteners/levellers, uncoilers, tension rolls
The table below gives typical configurations and countermeasures for common metallurgical equipment positions. Specific designations and parameters must be verified against actual operating conditions.
| Application Position | Recommended Type | Dominant Failure Mode | ZBZ Technical Response |
|---|---|---|---|
| Continuous caster segments / withdrawal & straightening rolls | Spherical roller bearings (increased clearance, high-temperature type) | Thermal softening, lubricant carbonisation, ingress of water and mill scale | High-temperature stabilising heat treatment + triple sealing + water-resistant high-temperature grease; clearance and internal geometry redesigned to the temperature field |
| Mill work rolls / backup rolls | Four-row cylindrical roller bearings + thrust (or spherical roller thrust) combination | Edge stress spalling, cage fracture, smearing | Vacuum-degassed / electroslag-remelted (ESR) steel + logarithmic profiling + reinforced one-piece cage; P5/P4 accuracy class with oil film verification |
| Reheating furnace and mill roller tables | Large deep groove ball bearings / spherical roller bearing units | Large populations, frequent individual replacement, high maintenance cost | Lubricated-for-life sealed units + high-temperature grease; temperature and vibration monitoring ports can be provided for condition monitoring |
| BOF tilting mechanism | Large spherical roller bearings / spherical plain bearings | Low-speed heavy-load oscillation, shock loading, boundary lubrication | High-toughness material + thickened cage + extreme-pressure lubrication concept; combined with a shaft system strength review |
| Coilers / uncoilers | Cylindrical roller + tapered roller combination | Axial float, loss of preload, vibration | Supplied as matched pairs with adjustable preload and clearance; installation and preload procedure documentation included |
| Straighteners / temper mills | Cylindrical roller bearings, spherical roller bearings | Eccentric loading, roll-stack deflection, repeated shock | Self-aligning design + profiled raceways; redesign of housings and fit tolerances where required |
| Ladle turrets / refining equipment | Large slewing rings and extra-large custom-engineered bearings | Very large dimensions, heavy load at low speed, no possibility of lifting out on site | One-piece or split custom design with FEA verification; installation and maintenance procedure package supplied |
We break the service life of a metallurgical bearing down into five controllable variables, each with its own process specification and inspection standard.
Rating life is calculated from the actual load spectrum, with lubrication, contamination and temperature correction factors applied to deliver a predictable life band.
Failed samples are recovered for macro and micro examination, separating the four root-cause families — material, mounting, lubrication and overload — into a corrective action list.
Temperature, vibration, load and lubrication condition are measured in the field, avoiding the systematic error that comes from selecting straight out of the catalogue.
A bearing history is maintained per machine, and material, clearance and sealing are iterated round by round so that service life rises batch after batch.
We are prepared to set improvement targets with you on "bearing cost per tonne of steel" or "annual downtime hours per line", and to have them verified against real operating data.
"Caster segment bearings used to need replacing every three months — as soon as cooling water got in, the grease emulsified. After switching to the ZBZ high-temperature sealing package we stretched the replacement interval to more than double what it was, and we can finally plan our outages in advance."
Send us the position, designation, loads and current service life data, and you will receive a targeted improvement proposal and life verification report within 72 hours.
