NSK Case Study


Cold Rolling Mill

Cost Savings: $17,472

A steel manufacturer was experiencing continued failures of bearings on their Cold Rolling Mill. NSK engineers conducted an application review and found the highly contaminated operating conditions were causing the unexpected failures. This resulted in costly unplanned shutdowns and a reduction in production ratios. NSK STF bearings, made of a long-life Super-Tough Steel, were recommended. STF is developed specifically to combat debris contamination that enters the lubricant. After a four-month running trial, the bearings were returned for inspection. The laboratory found a residual life between 29-50 months. To date, the customer has replaced the bearings once per year during the annual scheduled maintenance.

Key Facts

Cold Rolling Mill
Highly contaminated operating conditions
Extremely short bearing life: 3-4 months
Bearing and grease analysis revealed contamination caused the failures
NSK Solution: Long-life Super-Tough Steel Spherical Roller Bearings
Longer life with superior resistance against wear, seizure and heat
Significant increase of bearing life to 29-50 months

Cold Rolling Mill

Value Proposals

The NSK Technical Department analyzed grease samples and inspected bearings to find the root cause of failure
NSK Engineers recommended Spherical Roller Bearings in Super-Tough Steel
After a four-month trial (equivalent to the original bearing lifetime), bearings were disassembled and returned to the plant for analysis
The results showed that the bearing still had additional operating life (10 times the initial lifetime)
Significant cost savings were achieved based on reduced bearing replacement rate, reduced line stoppage and associated maintenance costs

Product Features

Advanced Super-TF material composition containing appropriate levels of chrome and molybdenum for increased hardness
Innovative heat treatment technology to optimize retained austenite and formation of finer carbide and carbonitride particles
Significantly outperforms standard bearing steel
Up to 10 times service life with contaminated lubrication; 2 times in clean lubrication
Up to 4 times the service life at 160°C/320°F
Less than one-third the rate of wear
40% improvement in seizure resistance
Spherical Roller Bearings
of STF Steel composition

Cost-Savings Breakdown

  Before Cost NSK Solution Cost  
  Standard Spherical Roller Bearing spend $10,290 Super Tough Spherical Roller Bearings spend $3,430  
  Unplanned production downtime $9,647 No unplanned downtime $0  
  Bearing replacement maintenance $1,286 Bearing replacement maintenance $321  
  Total Costs $21,223 Total Costs $3,751  
Before Cost
Standard Spherical Roller Bearing spend $10,290
Unplanned production downtime $9,647
Bearing replacement maintenance $1,286
Total Costs $21,223
NSK Solution Cost
Super Tough Spherical Roller Bearings spend
No unplanned downtime $0
Bearing replacement maintenance $321
Total Costs $3,751

Your Partner for Machine Optimization

Our AIP Added Value Program is based around a simple proposition: ‘improvement pays’. By working with you throughout the AIP Value Cycle, we will help you achieve improvements in machine reliability, productivity and performance, all of which carry a tangible and measurable cost benefit – and we have the tools to prove it! That’s what we mean by improvement pays.