[jkessler_22]

Yes, the 12V speed vs. torque performance will essentially be 3/5 of the value at 20V. You can just translate the speed curve (the "N"-line) downward parallel to the existing one on the graph.

The current response is a different story, since current is proportional to torque (speed being proportional to the input voltage). The current draw would follow the same curve (the "I"-line) as shown, but the maximum current (stall current) would be scaled back to the point where the speed curve crosses the x-axis (at zero speed).

This would make more sense if you extrapolated the curves shown on the graph to the 65.7 milli-Newton-meter stall torque and the 6.20 A stall current that the motor is rated for. Then, redraw the de-rated speed curve and a vertical line drawn at the stall point would provide the new expected stall current. In simpler terms, as long as the motor is still rotating, the current draw for a given torque would remain essentially the same regardless of speed.

Hope this helps, without being too confusing !