Hot ductility of TWIP steels
type: CreativeWork
description: TWIP (Twining Induced Plasticity) steel is very promising AHSS (Advanced High Strength Steel) grade owing to its superior toughness and ductility. Recently it has attracted the interest of the automotive and steelmaking industries, as the need for reducing weight to provide better fuel efficiency is of paramount importance with the gradual depletion of fuel resources. A high Al, TWIP steel is being commercially developed as Al has been found very well in delaying fraction in deep drawn products. However these steels are difficult to continuous cast and cracking can occur at the slab surface. Therefore it becomes very important to gain an understanding of the cause of this cracking, in order to prevent their occurrence. To assess the likelihood of the cracking in these high Al TWIP steel slabs (1~1.5%Al, 0.6%C, 18%Mn), conventional hot tensile tests were performed to simulate the continuous casting process. A variety of TWIP steels were tested in order to determine the influence of such factors as chemical composition, cooling rate and thermal cycle on hot ductility. Using a cooling rate of 60oC/min after heating to 1250oC, ductility was generally <40% RA (Reduction of Area) indicating that these high Al TWIP steels it will be difficult to cast without transverse cracking occurring. The 1.5%Al containing steels had worse ductility than the low Al containing steels (0.02%Al) because of the presence of large amounts of AlN precipitated at the austenite grain boundaries. Reducing the Al and N level improved ductility. Higher strength Nb/V high Al containing TWIP steels were also examined although ductility was likely to be worse than the simpler microalloying free TWIP steels as was confirmed. Increasing the cooling rate from 60 to 180oC/min after melting caused the ductility to further deteriorate and high N levels produced only a small reduction in the ductility, probably because ductility is so poor. Increasing the S level from 0.003 to 0.01% caused the ductility to …
abstract: TWIP (Twining Induced Plasticity) steel is very promising AHSS (Advanced High Strength Steel) grade owing to its superior toughness and ductility. Recently it has attracted the interest of the automotive and steelmaking industries, as the need for reducing weight to provide better fuel efficiency is of paramount importance with the gradual depletion of fuel resources. A high Al, TWIP steel is being commercially developed as Al has been found very well in delaying fraction in deep drawn products. However these steels are difficult to continuous cast and cracking can occur at the slab surface. Therefore it becomes very important to gain an understanding of the cause of this cracking, in order to prevent their occurrence. To assess the likelihood of the cracking in these high Al TWIP steel slabs (1~1.5%Al, 0.6%C, 18%Mn), conventional hot tensile tests were performed to simulate the continuous casting process. A variety of TWIP steels were tested in order to determine the influence of such factors as chemical composition, cooling rate and thermal cycle on hot ductility. Using a cooling rate of 60oC/min after heating to 1250oC, ductility was generally <40% RA (Reduction of Area) indicating that these high Al TWIP steels it will be difficult to cast without transverse cracking occurring. The 1.5%Al containing steels had worse ductility than the low Al containing steels (0.02%Al) because of the presence of large amounts of AlN precipitated at the austenite grain boundaries. Reducing the Al and N level improved ductility. Higher strength Nb/V high Al containing TWIP steels were also examined although ductility was likely to be worse than the simpler microalloying free TWIP steels as was confirmed. Increasing the cooling rate from 60 to 180oC/min after melting caused the ductility to further deteriorate and high N levels produced only a small reduction in the ductility, probably because ductility is so poor. Increasing the S level from 0.003 to 0.01% caused the ductility to …
author: Eon Kang, Shin
keywords: TA Engineering (General). Civil engineering (General)
date published: 2014-12
date modified: 2026-07-24T01:39:24Z
provider: City University of London
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: City University London