Evaluation of Formability of Thin Sheet Metal from Mechanical Properties


Article Preview

The evaluation of formability for sheet metals by means of different tests such as hole-expansion and forming limit tests is widely used in industry. The experimental efforts for these tests and the scatter of the results are much higher than those for the identification of the mechanical properties of various material charges for the same material grade in tensile test. Difficulties in accurate formability evaluation for new steel grades, such as AHSS, have necessitated a review of the existing prediction methods. Consequently, a new formability criterion was developed from the statistical relations of parameters for approximately fifty steel grades in various thickness ranges. The criterion considers the combination of mechanical properties from the tensile testing as the yield strength, tensile strength and total elongation and plastic deformation energy in a single value. The quality ranking of different charges and coils was made by using of the criterion as well as, for comparison, other well-known criteria which are currently used in the industry. The results obtained involving the new formability criterion seems to be accurate for a wide range of material grades and thicknesses, from the viewpoint of automotive design requirements.



Edited by:

Heinz Palkowski, Vladimir Yukhvid, Dmitriy Chernikov, Alexander Amosov, Fedor Grechnikov, Yuriy Klochkov, Ekaterina Nosova and Yaroslav Yerisov




S. Guk, "Evaluation of Formability of Thin Sheet Metal from Mechanical Properties", Key Engineering Materials, Vol. 684, pp. 80-85, 2016

Online since:

February 2016





* - Corresponding Author

[1] R. Gadney, Sheet metal formability, Advanced materials & processes. 8 (2002) 33-36.

[2] DIN EN ISO 12004-1: Metallic materials – Sheet and strip - Determination of forming-limit curves – Part 1: Measurement and application of forming-limit diagrams in the press shop (2009).

DOI: https://doi.org/10.3403/30150415

[3] DIN EN ISO 12004-2: Metallic materials – Sheet and strip - Determination of forming-limit curves – Part 2: Determination of forming-limit curves in the laboratory (2009).

DOI: https://doi.org/10.3403/30150423

[4] ISO 16630: Metallic materials — Sheet and strip — Hole expanding test (2009).

[5] M. Braun, M. Borsutzki, M. Bülter, B. Carlsson, P. Larour, A. Richter, E. Atzema, S. Geisler, Results of an European round robin test for hole expansion test according ISO 16630, in: International Conference: New Development in Sheet Metal Forming, Fellbach, Germany (2011).

[6] DIN EN 10338: Hot rolled and cold rolled non-coated flat products of multiphase steels for cold forming – Technical delivery conditions (2010).

DOI: https://doi.org/10.3403/30280399

[7] DIN EN 485-2: Aluminium and aluminium alloys – Sheet, strip and plate – Part 2: Mechanical properties (2009).

[8] DIN EN 10149-2: Hot-rolled flat products made of high yield strength steels for cold forming – Part 2: Delivery conditions for thermomechanically rolled steels (1995).

DOI: https://doi.org/10.3403/30239495

[9] D. Yeong, O. Orringen, G. Sih, Strain energy density approach to stable crack extension under net section yielding of aircraft fuselage, Journal theoretical and applied fracture mechanics. 22 (1995) 127-137.

DOI: https://doi.org/10.1016/0167-8442(94)00053-4

[10] N.A. Shulika, Formability criterion for cold-rolled steel sheet, Izvestija Akademii Nauk SSSR, Metally. 1 (1989) 129-131.

[11] A. YU. Averkiev, Evaluation of formability of sheet and tube rolling products, Soviet forging and sheet metal stamping technology. 2 (1990) 19-24.

[12] V.A. Skudnov, L.D. Sokolov, On a criterion of plasticity for metal forming, Izvestija Akademii Nauk SSSR, Metally. 4 (1965) 117-125.

[13] V.A. Ivoditov, About formability indicators of automotive steels, Metally. 4 (2007) 54-61.

[14] N.D. Alexopoulos, Low-alloy TRIP steels: Evaluation of the mechanical performance with regard to material design requirements in the automotive industry, Steel research international 2 (2006) 129-138.

DOI: https://doi.org/10.1002/srin.200606365

[15] DIN EN ISO 6892-1: Metallic materials – Tensile testing – Part 1: Method of test at room temperature (2009).