In: Mechanical Engineering
You are to make a bowling ball out of 2024-0 by forging in an impression die with flash. What force (tons) is needed? What will be the weight of the finished bowling ball?
Yield strength = 75 MPa = 11 ksi
Ultimate tensile strength = 190 MPa = 27 ksi
Max bowling ball diameter = 8.595 inches
Density = 0.1 lbs/in3
according to the information provided,
we understand that there is negligiable friction acting at the die-workpiece interface.
hence, forging load = compressive force acting on the cross-section of workpiece
the compressive force, F = Y*A
where, Y= yield strength of the material or flow stress
and, A = cross section of bowling ball on which the impression force will be acting
thus, A = (4r2)/2 = 2r2
where r = radius of the bowling ball
A= 2* * (8.595*0.0254)2 meter2 = 0.3 meter2
and Y= 75 MPa
thus compressing force, F = (75 x 106)* 0.3 = 22.5 x 106 N = 2294.36 ton (metric)
Now to find the weight of the bowling ball,
m = volume*density
volume of ball = (4r3)/3 = 4**(0.1093)/3 = 0.005424 meter3
density of 2024-0 aluminium = 0.1 lbs/in3 = 0.1* 27679.905 kg/meter3 = 2767.99kg/ m3
thus weight of finished bowling ball = 2767.99 * 0.005424 kg = 15.01 kg