What do you (railroad welder) use for electric welding, rod, preheat and postheat procedures?
Tom Koehler Responds:
I use a Hardalloy 118 rod in 1/4" diameter at about 300 amps for welding on manganese alloy frogs, with a
fine water mist after peening the weld - keeps the temperature of the base metal down below 450 deg. on
big buildup/repair jobs... alternatively, I use a 1/16" flux cored wire 219-0 on manganese frog work -
at varying currents up to nearly 300 amps - again peening and cooling between passes to keep the
temperature of the metal down.
For arc welding carbon steel rail, I use Railend 932-0 stick, 1/4" at close to 300 amps... or Railend 932-0
wire 1/16" at varying currents up to nearly 300 amps. the rail is preheated to abnout 800-1000 degrees
(black-red heat in sunlight) before welding, and kept hot during the weld. post-heating to same
temperature and "natural" cooling rate to ambient.
I have had some cracking when not able to properly preheat the rail and then welding with wire, but had good
results in similarly constrained heating circumstances and using the 1/4" stick at high heat. Maybe
because of the bigger puddle, the stick provided a kind of "self-preheat" or something.
No failures with the big stick, tho. This is extremely heavy haul railroad at class III speeds. The material
stands up well if taken care of. (our ore cars are only 24 feet long and have a gross weight of 75
tons... compare to other roads "heavy" cars of 100 ton gross - but more than twice as long as our cars),