"Ok, fair enough.
But I'm showing that it would take well over 200,000 pounds of force to bend a schedule 40 pipe 3/4 of an inch over a span of 10 inches."
You were assuming elastic deformation which it was NOT. It failed at a much smaller load and subsequently deformed 3/4 inch
To do this problem you need an accurate assessment of the dynamic load ( dragging the load up a chain under the worst conditions, namely startup when the motor accelerates the load.
You need the maximum motor startup torque which may be as much as 3 to 5X the nominal motor design torque.
Next you write the equation
which is the energy equation
x= the distance the load climbs for one revolution of the motor shaft
T= maximum torque delivered by motor
F= the maximum force applied to the chain that lifts the load and is the pipe design force.
On top of this you need a factor of safety of at least 3.
Not so simple. DO NOT use the weight of the load for the design calculation.