Hot Ductility Behavior of a Peritectic Steel during Continuous Casting

Estermann

et al. 2020

steel research int.

During the continuous casting process, alloys may be more susceptible to crack initiation under some conditions due to lower ductility. A Ti–Nb microalloyed steel is subjected to in situ melted hot tensile tests to evaluate its hot ductility behavior. The ductility is examined at different strain rates and temperatures. The samples are heated with an induction coil to the melting temperature in a vacuum atmosphere. Afterward, they are cooled to the desired test temperatures. Hot tensile tests are conducted by a thermomechanical simulator with strain rates varying from 10−5 to 10−2 s−1. The results show a ductility minimum around 800 °C for the standard strain rate of 10−3 s−1 and a significant influence of the changes in strain rate in the behavior of the alloy for all the tested temperatures. The fracture surfaces are compared for 700, 800, and 900 °C at 10−4, 10−3, and 10−2 s−1, as well as the microstructure. Computer simulations are done for the determination of the transformation temperatures, Scheil–Gulliver solidification simulation, and analysis of the precipitation kinetics during the tests. The results from simulations are discussed in comparison with the ones seen experimentally.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Strain Rate on the Hot Ductility Behavior of a Continuously Cast Ti–Nb Microalloyed Steel

Gontijo

Estermann

et al. 2020

steel research int.

“…During the continuous casting of steels, surface and internal cracks can be originated by the different thermal and mechanical stresses present [1][2][3][4]. The physical simulation of the most widely used process in steel production is important for product quality and savings, once it can help the improvement of the hot ductility, consequently reducing the incidence of cracks [5,6].…”

Section: Introductionmentioning

confidence: 99%

Holding Time Influence on the Hot Ductility Behavior of a Continuously Cast Low Alloy Steel

Gontijo

Ilie

et al. 2020

Metals

Cracking during the continuous casting process is undesirable and continuous work is being carried out to find further improvements and understand the mechanisms that lead to failure. Investigations on the hot ductility behavior of a continuously cast low alloyed steel using different holding times before straining were done in the present work. Samples were heated to melting temperature in a vacuum atmosphere and then cooled to one of the three test temperatures chosen: 750, 850, and 900 °C. When the desired temperature was reached, the sample was isothermally held for either 10, 90, 300, or 3600 s before the tensile test started, with a strain rate of 10−3 s−1. The reduction of area was measured, SEM images of the fractured surfaces were taken plus LOM images for the analysis of the microstructure. The results show that there was no significant change in the ductility at any of the temperatures until 300 s, with a change in behavior at 3600 s. This was further confirmed with the images and precipitation kinetics simulations. The results are described and compared.

“…During the straightening operation in continuous casting, the steel slab is subjected to high mechanical as well as thermal stresses. This may cause surface and internal tears that can lead to a loss of product yield and quality (Ref [1][2][3][4]. The sensitivity of continuously cast steels to transverse cracking can be primarily addressed to the poor hot ductility at temperatures between 700 and 1000°C; this is the temperature range where the straightening operation takes place ( Ref 5).…”

Section: Introductionmentioning

confidence: 99%

Influence of Thermal History on the Hot Ductility of a Continuously Cast Low Alloyed Cr-Mo Steel

J. of Materi Eng and Perform

Ilie

Six

et al. 2018

The hot ductility of a low alloyed Cr-Mo steel has been investigated to evaluate the surface cracking sensitivity within the straightening or unbending regime during the continuous casting process. Tensile samples were subjected to various thermal treatments, including melting and solidification, and were tested at deforming temperatures ranging between 600 and 1100°C using a strain rate of 10 23 s 21. Hot ductility was evaluated based on reduction in area measurement and metallographic investigations. The investigated steel exhibits a drop in ductility at around 800°C due to intergranular cracking. Microstructural examinations and supplementary thermokinetic computer simulations were carried out to describe the evolution of the microstructure during solidification and cooling.