The study tests the validity of the tensile hot ductility test for assessing cracking during the straightening operation. Steels with a thin film of deformation induced ferrite (DIF) or fully austenitic when straightening were examined. In both cases dynamic recrystallisation (DRX) occurs at high temperatures. However, DRX is not possible on straightening, the grain size being too coarse and strains too low. When, DRX occurs, ductility is overestimated compared to the un-recrystallised condition on bending. For steels with DIF films if the depth of the trough is ≥40%RA (reduction of area) cracking is unlikely. However, for TWIP steels, the estimated RA for unrecrystallised ϒ can be much < 40% causing cracking even though measured ductility is well in excess.

该研究测试了拉伸热延展性测试在矫直操作过程中评估开裂性的有效性。检验了矫直时具有变形感应铁素体（DIF）薄膜或完全奥氏体薄膜的钢。在这两种情况下，动态重结晶（DRX）都会在高温下发生。但是，在矫直时无法进行DRX，因为晶粒尺寸太粗，应变太低。当发生DRX时，与弯曲时未重结晶的情况相比，延展性被高估了。对于带有DIF膜的钢，如果槽的深度≥40％RA（面积减小），则开裂是不可能的。但是，对于TWIP钢，即使测得的延展性大大超出，未结晶ϒ的估计RA可能大大小于40％，从而导致开裂。