Mai Huang, James C. Gerdeen, Springback of Doubly Curved Developable Sheet Metal Surface - An Overview, SAE Transactions, Vol. 103, Section 5: JOURNAL OF MATERIALS & MANUFACTURING (1994), pp. 718-731 ...

C=0.668+0.326 K2 Because sheet metals vary from batch to batch, K and C values are best determined from test-bending a material sample and computing new values, rather than relying on previously ...