What rolling bearings are usually used in hot strip mills?

Oct 28, 2021

EXTENDING UPTIME IN EXTREME ENVIRONMENTS

As a hot strip of steel passes through a series of rolling stands that reduce and alter its shape and length, the supporting bearings must endure relentless punishment in the form of high heat, heavy and impact loads, variable speeds with rapid accelerations, and the constant presence of cooling water. All while running with accuracy to meet increasingly stringent standards for precision in rolled steel.

Here, FV delivers our highest capacity bearing solutions not only to withstand the heavy radial, axial and impact loads transmitted in work rolls and back-up rolls, but to deliver operating reliability in a water and contaminant-laden operating environment.

Multi row cylindrical roller bearings Mostly used for Back-up roll. Bear most of the rolling load. Unable to bear axial force	DOUBLE-ROW TAPERED ROLLER BEARINGS (Various design) Withstand heavy radial loads and thrust load support in back-up rolls.	Four row tapered roller bearings    Mostly used for Work roll, It can bear axial load

APPLICATION-OPTIMIZED SOLUTIONS

Amid high heat, mill scale and water penetration, FV Sealed-Clean Work Roll Bearings deliver long-life wear and contaminant resistance for reduced bearing replacement and grease consumption.

KEY FACTS

› Plate Rolling Mill

› Open work roll bearings required daily maintenance and regreasing

› Efficiency improvement sought by the customer

› FV solution: Sealed Clean Design 

› Benefits: improved grease retention, improved bearing protection, reduced disposal costs and maintenance time.

VALUE PROPOSALS

› Analysis of the existing bearings showed that grease retention and excessive maintenance were a major issue.

› FV Engineers were able to recommend Sealed Design bearing options together with improved material technology.

› Consideration of the existing bearing arrangement allowed FV to make recommendations on best fit and appropriate bearing design.

› Technical support was then provided to trial the proposed bearing arrangement.

› Results showed a significant reduction in grease usage.

PRODUCT FEATURES

› Available with high purity high-carbon chromium steel and carbonitriding shell hardened steel material, providing significantly longer service life under heavily contaminated operating conditions.

› Higher load capacity achieved with optimized internal design wider cage diameter, increased number of rollers and larger rollers.

› Helical bore groove prevents creeping on the shaft.

› Advanced compact main seal / seal holder and bore seal designs.

› Bore seal prevents the buildup of negative pressure that can cause the entry of water through the main seals.

› Sealed design solution significantly reduces grease consumption.

KEY FACTS

› Four-Row Tapered Roller Bearings running only 1400 hours before needing replacement.

› Failures were causing frequent line stoppages.

› FV Solution: High purity high-carbon chromium steel and carbonitriding shell hardened steel bearings with modified internal design

› Increased bearing life reduced bearing consumption, reduced downtime, reduced maintenance costs.

VALUE PROPOSALS

› FV engineers inspected the machine and operating conditions.

› The Analysis showed that the existing bearing solution was not adequate for the application.

› Due to the severe operating conditions, FV recommended additional modification of the bearings internal design along with a suggested contact angle change.

› Training was provided regarding root cause failure to prevent further issues.

› The customer received increased bearing life and reduction in maintenance costs, bearing consumption and downtime.

PRODUCT FEATURES

› Advanced purity high-carbon chromium steel and carbonitriding shell hardened steel material composition containing appropriate levels of chrome and molybdenum for increased hardness.

› Innovative and patented heat treatment technology to optimize retained austenite and formation of finer carbide and carbonitride particles.

› Significantly outperforms standard bearing steel in seizure resistance, rate of wear and service life.

› Reduced non-metallic inclusions on raceway surface inhibiting the generation of surface cracks.

CASE SHOW

FV can provide users with more high-end original grease. This is difficult for other Chinese suppliers to achieve. PALMAX RBG