A cold forming process on the design of lightweight steel structures can result in the increase of material mechanical properties of the structures at the exact loction where the cold working process takes place. two methods of estimating the increase on the yield strength of the structural materials at the bend cornerhave been used here. Both methods are based on bend comer models affected by bending only (A purely flexural-loaded comer model) and by interaction of bending and radial pressure ( A combined-flexural and radial pressure corner model). Investigation on the increase of yield strength is aimed at the bend corner material of a lightweight channel steel section cold-formed using a plate folding machine. The increase of yield strength estimated by both models is compared to the yield strength of the ssction virgin material. Observation on the comarison results of yield strength before and after cold forming indicates that the percentage of increasing yield strength is extremely affected by variation on parameters of bend corner radius and mechanical properties of the section virgin material. Harkali etiyono-BPPT
