How to Calculate Tonnage [FREE FORMULA]

The Tonnage Formula is the pressure required in tons to cut a blank or contour using a flat faced punch with no shear. Tonnages can be calculated for forming, bending, cutting, drawing, and blanking operations. Having the ability to calculate the tonnages for a sheet metal project is vital for the completion and success of your project.

FORMULA

T = P x Th x C

T = Pressure required in tons

P = Perimeter of blank in inches

Th = Thickness of material

C = Constant (see common ones below)

Constant = The material shear strength/2000 pounds

EXAMPLE

.050 CR Steel, 1/2 Hd; Cutting edge of 12 linear inches T

= 12 x .050 x 32

T = 20 tons required

CONSTANTS

Aluminum– Soft-11

T4/T6-15  

Steel– HR/Cold Rolled-27

1/2 Hard-32

Stainless Steel– Annealed-37

1/2 Hard-50

4130 AQ – 40

Brass– 1/2 Hard-22

Hard-25

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