of the rails at approximately 35 degrees full bevel on the head,
35 degrees double bevel on the web, and 35 degrees full bevel on
the upper side of the base. Retain a narrow "nose" of
approximately 2 mm (1/16 inch) 1/16 inch of original rail-end face
across the base and up the web, following beveling operation, to
permit proper alignment of rail ends. When beveling with a torch,
first preheat each rail end to 260 degrees C (500 degrees F) 500
degrees F. After torch cutting, grind off scale and oxides.
Grind level faces only after preheating. Use proper grinding
wheel and speed to avoid grinding "burns" or formation of "hard
spots" from localized overheating.
b.
Align the beveled rail ends, allowing approximately 3 mm (1/8-inch)
1/8-inch root clearance, and place a copper shim under the joint
opening. Clamp the rails during the welding with up to 6 mm (1/4
inch) 1/4 inch vertical camber (ends high) in 1200 mm (4 feet) 4
feet, centered over the joint to compensate for contracting
distortion.
c.
Preheat the joint area to approximately 260 degrees C (500 degrees
F) 500 degrees F for a distance of 150 to 200 mm (6 to 8 inches) 6
to 8 incheson each side of the joint using a suitable heat source,
such as an oxy-acetylene or propane torch.
d.
Initiate arc welding of the joint immediately after preheating in
the following sequence: base, web, and head. Weld alternately on
both sides of base and web. Do not entrap foreign material, such
as slag, in the weld. Grind, chip, or arc-air the root of the
initial weld to sound metal before welding is started from the
second side. Maintain a 260 degrees C (500 degree F) 500 degree F
to moderately higher interpass temperature. Proceed with welding
until the joint is completed and sufficient metal has been
deposited to permit grinding to finish contour in the head area.
Provide slight reinforcement of the web and top of the base areas.
e.
Postheat the joint area to approximately 370 degrees C (700
degrees F) 700 degrees F immediately after the welding operation,
using the same technique for preheating. After postheating,
protect the weld area against rain and snow and cool as slowly as
possible by covering with an insulating blanket.
f.
Grind the excess deposited weld metal from sides and top of rail
head using heavy-duty grinder. Heat area of the weld to at least
290 degrees C (550 degrees F) 550 degrees F before and during
grinding. Grind the area smooth, finishing to within plus or minus
0.5 mm (0.020 inch) 0.020 inch of original contour. Use proper
grinding wheel, speed, and rate of metal removal to avoid grinding
"burns" or formation of "hard spots" from localized overheating.
Prevent grinding cracks.
g.
Measure temperatures specified by temperature pencils.
3.2.2.3
Electrical Flash-Butt Method
Welding process shall conform to applicable provisions of Chapter 4 of
AREMA Manual.
SECTION 14606N
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