Drawing pull force is calculated by multiplying the drawn workpiece exit area (Af) by the total drawing stress: Fdraw = Af * σdraw. The drawing stress combines ideal deformation work, die-workpiece friction, and redundant internal shear: σdraw = σflow * [(1 + μ/tan α) * ln(A0/Af) + (4 / 3√3) * tan α] - σback.

The optimum die semi-angle is the exact cone angle that minimizes total drawing force by perfectly balancing frictional drag (which decreases at steeper angles due to shorter contact length) against redundant shear deformation (which increases at steeper angles). It is formulated as αopt = √[(3√3 / 4) * μ * ln(A0 / Af)].

Centerburst occurs when drawing through an excessively steep die angle (α > 15°-20°) at modest area reductions. Non-homogeneous plastic deformation creates large internal redundant shears that induce intense triaxial hydrostatic tension along the centerline, nucleating internal arrowhead-shaped cracks.

Because the drawn section leaving the die must pull the material through without necking, drawing stress cannot exceed the work-hardened yield strength (σdraw < σyield). For ideal frictionless drawing, the maximum reduction is 63.2% [ln(A0/Af) = 1.0]. Under real industrial friction, practical single-pass reductions are limited to 30% to 45%.

Tube sinking (drawing a hollow tube without an internal plug or mandrel) leaves high residual tensile hoop stresses on the outer surface because the tube undergoes unconstrained radial bending. In brasses, copper alloys, and stainless steels, these residual stresses trigger delayed intergranular stress corrosion cracking unless relieved by prompt annealing.