Innovative Stainless Steel Applications in transport ... - Euro Inox

Figure 54. T-test principle for determining minimum bending radius (DOLTRAC p. 50).
The results are summarized in Table 22, where the minimum radius indicated shows no
outer-surface fractures on visual inspection. The result for grade 1.4318 2H C1000
1.9 mm is not available, since the material fully fractured during the first bending step.
Table 22. T-bend test results (DOLTRAC p. 50). RD = rolling direction, TD = transverse
direction.
Material Direction Result Rmin (mm)
304SP 2B 1.0 mm RD 0 T 1.0
TD 0 T 1.0
1.4318 2B 1.0 mm RD 0 T 1.0
TD 0 T 1.0
1.4318 2H C850 1.5 mm RD 0 T 1.5
TD 0 T 1.5
1.4318 2H C1000 1.2 mm RD 0 T 1.2
TD 0.5 T 1.8
4.1.2 Determination of sheet springback behaviour
The springback of the different project materials (together with other materials) was
investigated, to gain more detailed insight into the influence that thickness and the
degree of cold-rolling have on springback behaviour. The bending technique used was
air V-bending whereby the samples were formed in a V-shaped groove, using a tool
with a predetermined radius. Further test parameters are given in Table 23.
Table 23. Test parameters for springback investigations (DOLTRAC p. 51).
Parameter Value
V-opening 16 mm
Bending radii of the tool 1.0, 2.5 and 4.0 mm
Test direction Longitudinal and transverse
Punch velocity ≤ 10 mm/s
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