Advanced Product Solutions
Four-Row Tapered
Roller Bearings
Four-row tapered roller bearings are designed specifically to support the work rolls of rolling mill stands. As their purpose suggests, they are engineered to withstand heavy and impact loads transmitted – radially and axially – as steel passes through rolling stands and is reduced in thickness by the work rolls. They must also accommodate wide speed variations with rapid acceleration and deceleration.
Equally challenging to these bearings is the environment: not only high temperatures but mill scale contamination and water penetration as well. NSK four-row tapered roller bearings are available with long-life Super-TF steel to deliver superior durability and wear resistance. For aggressive environments, NSK’s Sealed-Clean design offers improved heat- and water-resistant sealing protection, promoting reduced grease consumption and maintenance costs.
Proven Benefits
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Higher reliability and longer operating life with Super-TF steel, reducing bearing replacement and maintenance intervals |
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Sealed-Clean solution extends bearing performance, promotes a cleaner work environment and significantly reduces grease consumption |
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Advanced AQGRD grease for sealed-type bearings provides optimal water-resistance, preventing grease deterioration and bearing damage |
Design Features
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Special design high load capacity four-row tapered roller bearing |
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With long-life Super-TF steel for dramatically longer service life under contaminated operating conditions |
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With machined steel window- and pin-type cages |
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Spiral groove on the inner ring bore to prevent creeping wear on the roll neck shaft |
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Available as open or advanced heat- and water-resistant sealed-type bearings |
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Sealed version available with long-life AQGRD R1 water-resistant grease |
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Corrosion resistant phosphate option for inner ring |
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With special radial and axial internal clearances |
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Available in inch and metric design types |
NSK CASE STUDY
WORKING THE PROBLEM,
OPTIMIZING UPTIME
A major steel producer approached NSK experts with the challenge to extend replacement intervals for the four row tapered
roller bearings supporting the work rolls of their hot strip mill. Under relentlessly severe mechanical and environmental operating conditions,
bearings were achieving a maximum of 1,400 hours before requiring replacement at significant machine downtime, bearing replacement and maintenance costs to the mill.
| REVIEW THE CASE STUDY |  |
Designation System (Sealed Type)
Bearing Dimensions and Operating Values (Sealed Type)
| BASIC BEARING NO. | BEARING DIMENSIONS | BASIC LOAD RATINGS | CONSTANT | AXIAL LOAD FACTORS | ||||||||
| mm | kN | |||||||||||
| d | D | B4 | C4 | r (min) | r1 (min) | Dynamic | Static | e | Y2 | Y3 | ||
| STF170KVS2401Eg | 170 | 240 | 175 | 175 | 2.5 | 2.5 | 1 020 | 2 010 | 0.32 | 3.2 | 2.1 | |
| STF215KVS2851Eg | ● | 215.9 | 288.925 | 177.8 | 177.8 | 3.3 | 0.8 | 1 070 | 2 350 | 0.49 | 2.1 | 1.4 |
| STF216KVS3351Eg | ● | 216.103 | 330.2 | 263.525 | 269.875 | 3.3 | 1.5 | 2 290 | 4 550 | 0.46 | 2.2 | 1.5 |
| STF220KVS3301Eg | 220 | 330 | 260 | 260 | 3.0 | 4.0 | 2 330 | 4 800 | 0.40 | 2.5 | 1.7 | |
| STF220KVS3151Eg | ● | 220.662 | 314.325 | 239.712 | 239.712 | 3.3 | 1.5 | 1 960 | 4 350 | 0.33 | 3.0 | 2.0 |
| STF228KVS3151Eg | ● | 228.6 | 311.15 | 200.025 | 200.025 | 3.3 | 1.5 | 1 560 | 3 500 | 0.33 | 3.0 | 2.0 |
| STF234KVS3251Eg | ● | 234.95 | 327.025 | 196.85 | 196.85 | 3.3 | 1.5 | 1 550 | 3 200 | 0.46 | 2.2 | 1.5 |
| STF241KVS3451Eg | ● | 241.478 | 349.148 | 228.6 | 228.6 | 3.3 | 1.5 | 2 020 | 4 150 | 0.35 | 2.9 | 1.9 |
| STF244KVS3251Eg | ● | 244.475 | 327.025 | 193.68 | 193.68 | 3.0 | 1.5 | 1 370 | 3 050 | 0.40 | 2.5 | 1.7 |
| STF245KVS3402Eg | 245 | 345 | 310 | 310 | 3.0 | 2.0 | 2 700 | 6 650 | 0.40 | 2.5 | 1.7 | |
| STF254KVS3552Eg | ● | 254 | 358.775 | 269.875 | 269.875 | 3.3 | 1.5 | 2 420 | 5 500 | 0.40 | 2.5 | 1.7 |
| STF260KVS3601Eg | 260 | 365 | 340 | 340 | 4.0 | 2.7 | 2 960 | 7 350 | 0.40 | 2.5 | 1.7 | |
| STF260KVS3651Eg | ● | 365 | 340 | 340 | 4.0 | 2.5 | 2 960 | 7 350 | 0.40 | 2.5 | 1.7 | |
| STF260KVS4251Eg | ● | 260.35 | 422.275 | 314.325 | 317.5 | 3.3 | 6.4 | 3 600 | 7 050 | 0.33 | 3.0 | 2.0 |
| STF266KVS3551Eg | ● | 266.7 | 355.6 | 230.188 | 228.6 | 3.3 | 1.5 | 1 960 | 4 600 | 0.35 | 2.9 | 1.9 |
| STF275KVS3801Eg | 275 | 380 | 340 | 340 | 3.0 | 3.0 | 3 100 | 7 750 | 0.32 | 3.2 | 2.1 | |
| STF276KVS3952Eg | ● | 276.225 | 393.7 | 269.875 | 269.875 | 3.3 | 1.5 | 2 720 | 6 100 | 0.45 | 2.2 | 1.5 |
| STF279KVS3952Eg | ● | 279.4 | 393.7 | 269.875 | 269.875 | 6.4 | 1.5 | 2 720 | 6 100 | 0.45 | 2.2 | 1.5 |
| STF279KVS3954Eg | ● | 393.7 | 320 | 320 | 6.4 | 1.5 | 3 100 | 7 350 | 0.40 | 2.5 | 1.7 | |
| STF280KVS3801Eg | 280 | 380 | 290 | 290 | 3.0 | 3.0 | 2 690 | 6 500 | 0.33 | 3.0 | 2.0 | |
| STF280KVS3804Eg | 380 | 340 | 340 | 4.0 | 1.5 | 2 870 | 7 650 | 0.33 | 3.0 | 2.0 | ||
| STF280KVS4301Eg | 430 | 350 | 350 | 3.5 | 2.0 | 4 100 | 8 558 | 0.40 | 2.5 | 1.7 | ||
| STF290KVS4001Eg | 290 | 400 | 346 | 346 | 4.0 | 3.0 | 3 250 | 8 400 | 0.40 | 2.5 | 1.7 | |
| STF304KVS4351Eg | ● | 304.648 | 438.048 | 280.99 | 279.4 | 3.3 | 3.3 | 3 100 | 6 750 | 0.45 | 2.2 | 1.5 |
| STF304KVS4155Eg | ● | 304.8 | 419.1 | 269.875 | 269.875 | 6.4 | 1.5 | 2 850 | 6 550 | 0.33 | 3.0 | 2.0 |
| STF304KVS4152Eg | ● | 304.902 | 412.648 | 266.7 | 266.7 | 3.3 | 1.5 | 2 760 | 6 500 | 0.33 | 3.0 | 2.0 |
| STF310KVS4301Eg | 310 | 430 | 310 | 310 | 3.0 | 3.0 | 3 350 | 8 200 | 0.46 | 2.2 | 1.5 | |
| STF310KVS4302Eg | 430 | 350 | 350 | 3.0 | 2.7 | 3 700 | 9 550 | 0.46 | 2.2 | 1.5 | ||
| STF317KVS4251Eg | ● | 317.5 | 422.275 | 269.875 | 269.875 | 3.3 | 1.5 | 2 740 | 6 750 | 0.34 | 3.0 | 2.0 |
| STF317KVS4451Eg | ● | 447.675 | 367 | 367 | 3.0 | 3.6 | 3 850 | 9 500 | 0.33 | 3.0 | 2.0 | |
| STF343KVS4551Eg | ● | 340.052 | 457.098 | 254 | 254 | 3.3 | 1.5 | 2 830 | 6 700 | 0.45 | 2.2 | 1.5 |
| STF355KVS4551Eg | ● | 355.6 | 457.2 | 252.412 | 252.412 | 3.3 | 1.5 | 2 650 | 6 750 | 0.32 | 3.2 | 2.1 |
| STF355KVS4851Eg | ● | 482.6 | 265.112 | 269.875 | 3.3 | 1.5 | 3 100 | 7 200 | 0.47 | 2.1 | 1.4 | |
| STF374KVS5051Eg | ● | 374.65 | 501.65 | 250.825 | 260.35 | 3.3 | 1.0 | 2 970 | 7 150 | 0.47 | 2.1 | 1.4 |
| STF384KVS5451Eg | ● | 384.175 | 546.1 | 400.05 | 400.05 | 6.4 | 3.3 | 5 250 | 12 400 | 0.33 | 3.1 | 2.1 |
| STF385KVS5151Eg | ● | 385.762 | 514.35 | 317.5 | 317.5 | 3.3 | 3.3 | 4 150 | 10 400 | 0.33 | 3.0 | 2.0 |
| STF390KVS5101Eg | 390 | 510 | 350 | 350 | 3.0 | 1.5 | 3 900 | 10 800 | 0.35 | 2.9 | 1.9 | |
| STF406KVS5451Eg | ● | 406.4 | 546.1 | 288.925 | 288.925 | 6.4 | 1.5 | 3 950 | 9 450 | 0.48 | 2.1 | 1.4 |
| STF406KVS5452Eg | ● | 546.1 | 330 | 330 | 6.4 | 1.0 | 4 350 | 11 000 | 0.48 | 2.1 | 1.4 | |
| STF406KVS5651Eg | ● | 562 | 381 | 381 | 6.4 | 3.3 | 4 950 | 11 900 | 0.33 | 3.0 | 2.0 | |
| STF409KVS5451Eg | ● | 409.575 | 546.1 | 334.962 | 334.962 | 6.4 | 1.5 | 4 500 | 11 700 | 0.40 | 2.5 | 1.7 |
| STF450KVS5901Eg | 450 | 595 | 368 | 368 | 5.0 | 4.0 | 5 550 | 15 000 | 0.33 | 3.0 | 2.0 | |
| STF457KVS5951Eg | ● | 457.2 | 596.9 | 276.225 | 279.4 | 3.3 | 1.5 | 4 000 | 9 850 | 0.47 | 2.2 | 1.4 |
| STF482KVS6151Eg | ● | 482.6 | 615.95 | 330.2 | 330.2 | 6.4 | 4.3 | 4 900 | 13 500 | 0.33 | 3.1 | 2.1 |
| STF489KVS6351Eg | ● | 489.026 | 634.873 | 320.675 | 320.675 | 3.3 | 3.3 | 4 850 | 12 500 | 0.38 | 2.7 | 1.8 |
| STF490KVS6201Eg | 490 | 625 | 385 | 385 | 3.0 | 3.0 | 5 650 | 16 600 | 0.32 | 3.2 | 2.1 | |
| STF558KVS7353Eg | ● | 558.8 | 736.6 | 455.6 | 457.2 | 6.4 | 3.3 | 8 300 | 23 000 | 0.35 | 2.9 | 2.0 |
| STF585KVS7751Eg | ● | 585.788 | 711.525 | 479.425 | 479.425 | 6.4 | 3.0 | 8 250 | 22 700 | 0.33 | 3.0 | 2.0 |
| STF660KVS8151Eg | ● | 660.4 | 812.8 | 365.125 | 365.125 | 6.4 | 3.3 | 6 050 | 17 700 | 0.33 | 3.0 | 2.0 |
| STF708KVS9351Eg | ● | 708.025 | 930.275 | 565.15 | 565.15 | 6.4 | 3.3 | 12 000 | 34 000 | 0.33 | 3.0 | 2.0 |
Extra-Capacity Sealed-Clean Four-Row Tapered Roller Bearings are made of NSK Super-TF material as the standard specification
Bearings marked ● are inch design.
Additional bearing designs / sizes are available. Please contact NSK for additional information.
