Page 220 - The Tribology Handbook

Bl1 Wheels, rails and tyres

Table 11.2 (continued)

Material Other
Speed (V) Eleuated temp. Wheel dia. Inflation pressure Wear
composition factors
Solid Load capacity important limiting Load capacity Load capacity is Not applicable Tyre damage, Le. Load
tyres roughly factor. proportional to dependent on bond failure, capacity
inversely Maximum (diameter)@ material, cracking, reduced if
proportional dependent on where p = 0.5 physical and cutting and wheel is
to speed with tyre material, to 1.25 mechanical tearing limit driven
rubber tyres e.g. 120°C for properties, load capacity
rubber tyres such as yield
strength and
Young’s
modulus

STATIC WHEEL LOAD ON 300 mm RADIUS HEADED RAILS, TON f
STATIC WHEEL LOAD ON FLAT HEADED RAILS (TONS f/lNCH WIDTH) ---a-
0 5 10 15 20 25 30
1300 I I I I I
80

1100
70
1000
60
900
. N C .-
N s
E
z 50 6
z
vi
$ 700 lJl w
w n:
a
I- t;;
v) 40 I-
I- 0
u Q
Q I-
k- z
$ 500 8
u
30
’
CRANE WHEEL
LOADS
300 20
10
100

0 50 100 150 200 250 300
STATIC WHEEL LOAD ON 300 rnm RADIUS HEADED RAILS, kN

Figure 7 7.4 Rail contact stress and its dependence on static wheel load and wheel diameter is shown for
flat-headed crane wheels and a typical main-line rail with 300 mm head radius. The predominant wear
mechanisms over the ranges of stress are shown. Wear of main-line rails typically takes the form of corrosion
followed by abrasion. Fatigue cracking and plastic deformation become important where load and traffic
density are high.
B11.4