Xtek Crane Wheels
Why Choose Xtek?
Crane Maintenance Spending
Survey Results From AIST Crane Symposium
Shafting
3%
Couplings
5%
Gearing
10%
Bearings
11%
Motors
12%
Brakes
16%
Wheel Assemblies 43%
Wheel Assembly Reasons for Replacement
Survey Results From AIST Crane Symposium
Spalled Tread 2%
Worn Tread 9%
Axle Breakage 13%
Others & Unknown 16%
Bearing Failure 21%
Worn or Broken Flange 39%
Typical Wheel Problems
 Spalling - Material or hardness is
not capable of carrying the load
 Broken Flanges – Flange hardness
to brittle to resist impact stresses
 Wear – Related to the hardness
properties of the wheel and the
operating conditions
Crane Wheel Performance
 LOAD - Heat treatment places
wheel tread in compression and
provides a deep case
 FRACTURE – Tough and ductile
core to address shock loads
during operation
Highest Stress
at Impact
 WEAR – High surface hardness
extends wheel life and reduces
friction with the rail
Compliance with AIST/AISE Technical Report No 6,
Dated June 2005
Sub-Surface
Shear Strength
Resistance to Spalling,
Flange Failure and Wear
 Heat Treatment places the wheel
tread and flanges in compression
allowing for higher load capability
 Contour case hardening pattern
provides a ductile core in the flanges
 Surface hardness provides wear
resistance
Xtek Contour Case Hardening
Xtek Wheel with WORN Tread and Flange
Through Hardened Flanges
High Risk of Fracture
Xtek Heat
Treating
Operations
Depth of Hardness
.160 – 200”
Surface Hardness
58 – 62 HRC
Xtek Crane Wheel
Contour Case Hardened
AISI 1055
Forged Steel
Core Remains Ductile
Soft Core
Flanges Not
Through-Hardened
Allowable Wheel Loads
(24” Wheel Diameter)
180
Thousands of Pounds
160
Heat Treated (320 BHN)
164
Case Hardened (58 HRC)
140
146
120
100
105
117
104
88
80
75
60
63
40
20
0
105
135
ASCE Rail Section
175
171
RESULT: 40% INCREASE IN CAPACITY
Operational Considerations
Industry Standards
AIST
 Straight Tread Bridge Drive Wheels Shall Have Tread
Diameters Matched Within 0.010” Maximum of Each
Other When Mechanically Connected
 All Other Applications, Including Tapered Tread, Shall
Have Bridge and Trolley Driver Wheels Matched Within
0.030” Diameter Maximum of Each Other
CMAA
 Drive Wheels Shall be Matched Pairs Within 0.001” per
Inch of Diameter or a Total 0.010” on Diameter,
Whichever is Smaller
PRECISION FINISHING OF
HARD TREAD
US Navy Crane Center
MIL-Handbook #1038
Weight Handling Equipment (Design Criteria)
Section 5.3.11 – Travel Wheels - Page #150:
“There is no detriment to large differences between
the wheel and rail head hardnesses. Experience
suggests that wear on both can only be improved by
increasing the hardness of either the wheel, rail head,
or both.”
Case Study: Crane Wheels
Problem:
 Application = Steel Mill Scrap Yard Crane
 Current Wheel Product = Rim Tough Wheel, 320 BHN
 Problem = Wheels replaced every 9 months
 Primary Cause = Tread wear and flange wear
Solution:
 Test established with Xtek contour hardened track wheels
Case Study: Crane Wheels
Results:
 Xtek wheels were monitored for 36 months
 Still in service at end of test
 Savings of $10,200 per wheel during the 36 month test and going…
 Xtek wheel cost $922 / each
 The existing wheel cost $650 / each

Three additional wheels would have been purchased
 Labor cost to change a wheel assembly from the crane = $600 / each

Three additional wheel assembly exchanges would have occurred
 Reconditioning changes avoided during the test = $2,150 / each

Three reconditioning expenses were avoided
 This test has also benefited the mill by the avoidance of unscheduled
downtime and now offers the potential for a reduction in inventory
WHEEL ASSEMBLIES
Crane Wheel Assembly Reconditioning
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Disassembly
Inspect
Reverse Engineer
Failure Analysis
Manufacture
Assemble
Why Xtek?
• Crane and Material Handling
Equipment expertise
• Involved in Crane and
Material Handling Standards
• In House Heat Treatment
• Full line of material
alternatives to address
application requirements
• 60+ Mechanical, Metallurgical
and Service Engineers
• World wide steel mill
experiences
•
•
•
•
•
Service capabilities
Reverse engineering
Failure analysis
Inventory management
Drawing and data
management
• Emergency response
capability
• Active in all Nucor flat
rolling facilities and most
of the structural mills
• ISO Certified
Xtek Crane Wheels
Thanks for your consideration!