Unusual Shaped Forging Breaks Ground -- Literally
Forging readily accommodates a wide variety of shapes while simultaneously
imparting exceptional strength. But when it came to a highly
unusual rotor arm fashioned in a three-spoke configuration,
no one was sure whether it could be done.
Deca Industries Ltd., Saskatoon, Saskatechewan, Canada,
is a 40-person industrial job shop that repairs heavy mining
equipment. Founded in 1977, Deca specializes in serving
the potash and the uranium mining industries.
This unique application arose when Deca's customer, International
Mining Corp. (IMC), wanted to fix a disabled rotor arm integral
to the operation of a continuous boring mining machine.
As the machine cuts through potash, the rotor arm holds
the tools that actually make the cuts.
Deca engineers determined that the part couldn't be repaired;
rather, it had to be replaced. This was no small decision
since the rotor arm is 90 in. in diameter, 4 ft thick, with
three telescoping arms and a total weight of 7,000 lb. Deca
began exploring fabrication options for the replacement
part. Since the existing component had been a casting, Deca
looked again at that method as well as machining and open
die forging alternatives.
"Acknowledging all the forging advantages, a question still
remained," said Francis Nagy, Deca's president. "Could this
part actually be manufactured as an open die forging? As
far as we knew, the rotor arm's unusual shape wouldn't normally
lend itself to forging." Yet Deca was intrigued. To investigate
further, Deca turned to Scot Forge, its Spring Grove, IL,
supplier of forged spindles and rings.
Several steps were needed to produce the rotor arm. Nagy
took the part's original blueprints and casting drawings
down to Scot Forge where manufacturing details were worked
out jointly. The new part started as a pancake-shaped piece
of 4140 alloy base stock that was then formed into a seamless
rolled ring via the open die forging process. Three torch-cut
sectors were then drawn out and forged into journals.
Once the forged part was finished, it was sent to Deca
for secondary processing.
"This was an enormous undertaking," Nagy said, "from the
sheer standpoints of size and shape. We were amazed with
When IMC received the part, it passed the quality inspection.
The new rotor arm has been in the field for two years now
and has performed to everyone's expectations.
steps were needed to produce this rotor arm - here the
first journal is being drawn out
the last journal
rotor arm forging - this part is used in the mining