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Michael Ferry - One of the best experts on this subject based on the ideXlab platform.

  • Recrystallisation processes in cold rolled low Carbon Steel Strip containing different starting microstructures
    Materials Science and Technology, 2010
    Co-Authors: Michael Ferry
    Abstract:

    AbstractThe effect of initial microstructure [acicular ferrite (AF); polygonal ferrite (PF); fine polygonal ferrite (FPF); bainite (B)] on the recrystallisation behaviour of cold rolled low Carbon (LC) Steel Strip was investigated. Steel Strip samples of 2 mm thickness were heat treated to produce FPF, PF, AF and B. The resulting materials, together with a twin roll cast LC Strip containing predominantly acicular ferrite (SC), were cold rolled to 50, 70 and 90% reduction and annealed for various times in the temperature range 580–680°C. The evolution of microstructure during rolling and recrystallisation was studied by optical microscopy, electron backscatter diffraction in SEM and TEM. The initial microstructure was found to have a substantial influence on the annealing behaviour. Recrystallisation was structure dependent with the rate of recrystallisation shown as FPF>B>PF>AF>SC during annealing at temperatures in the range 580–680°C. Both partly and fully recrystallised materials exhibited approximatel...

  • Recrystallisation textures in cold rolled low Carbon Steel containing ferritic and bainitic microstructures
    Materials Science and Technology, 2010
    Co-Authors: Michael Ferry
    Abstract:

    AbstractLow Carbon Steel Strip was heat treated to generate four different starting microstructures (fine and coarse polygonal ferrite, acicular ferrite and bainite) for investigating their influence on texture development during cold rolling and annealing. The starting materials were cold rolled to 50–90% reduction and annealed for various times in the temperature range 853–953 K. The resultant microstructures and textures were examined mainly by electron backscatter diffraction and X-ray diffraction. The initial microstructure strongly influenced the crystallographic rotation paths during cold rolling, whereby high strain deformation generated strong {223}〈110〉 texture components in the polygonal ferritic microstructures, whereas a strong {001}〈110〉 texture was produced in the acicular/bainitic microstructures. Subsequent annealing generated, to varying degrees, the classic {111}〈uvw〉 (γ-fibre) recrystallisation texture in all materials. Unexpectedly, coarse polygonal ferrite produced the strongest γ-fi...

  • Recrystallization Behaviour of Cold Rolled Low Carbon Steel Strip with Various Starting Microstructures
    Materials Science Forum, 2007
    Co-Authors: Michael Ferry
    Abstract:

    The effect of initial microstructure (acicular ferrite (AF), polygonal ferrite (PF) and Strip cast (SC)) on the recrystallization behaviour of low Carbon (LC) Steel was investigated. Steel Strip samples (0.05 wt.% C) of 2 mm in thickness were heat treated to produce an AF and PF microstructure from coarse austenite. The AF, PF and a similar chemistry SC sample manufactured from a twin roll caster were cold rolled to 50, 70 and 90% reduction, and annealed for various times in the temperature range 580-680 °C. The evolution of microstructure during recrystallization was studied by optical microscopy and electron backscatter diffraction (EBSD) in the SEM. The initial microstructure was found to have a substantial influence on the recrystallization behavior. PF recrystallized more rapidly than AF with SC showing extremely sluggish recrystallization behaviour. The recrystallizing grains in these initial microstructures have a lognormal distribution and the recrystallized number density (grains/mm2) decreased during annealing, with the initial microstructures affecting the degree of this decrease in number density.

  • Influence of Starting Microstructure on Texture Development in Cold Rolled and Annealed Low Carbon Steel Strip
    Materials Science Forum, 2005
    Co-Authors: Michael Ferry
    Abstract:

    The effect of initial microstructure on the recrystallization behaviour and texture development of low Carbon (LC) Steel was investigated. Steel Strip samples (0.05 wt.% C) of 2 mm in thickness were heat treated to produce a microstructure consisting predominantly of either polygonal ferrite or acicular ferrite. Samples were cold rolled 50, 70 and 90% reduction then annealed for various times in the temperature range 580-640 oC. The microstructures and textures produced by deformation and annealing were studied by optical microscopy and electron backscatter diffraction in the SEM. The initial microstructure was found to have a substantial influence on the rate of recrystallization and final texture. It was found that polygonal ferrite recrystallizes more rapidly than acicular ferrite with the former generating the strongest //ND recrystallization texture. The results are examined within the framework of improving the formability of LC Steel produced by direct Strip casting whereby controlled thermal and mechanical processing prior to cold rolling and annealing can generate the same types of initial microstructures, as studied in this work.

  • Microstructural control by secondary processing of Strip cast low Carbon Steel
    Materials Science and Technology, 2001
    Co-Authors: Michael Ferry, C. Page
    Abstract:

    AbstractThe secondary processing of low Carbon Steel Strip produced by twin roll casting was investigated to examine its effect on microstructural development and mechanical properties. The as cast microstructure is predominantly acicular ferrite with regions of bainitepearlite and polygonal ferrite. Deformation at temperatures below Ar1 produces a heterogeneous microstructure with regions of moderately deformed acicular ferrite adjacent to highly deformed regions containing shear bands. Cold rolled and warm rolled Steels show similar behaviour to conventional hot band in that dynamic recovery during warm rolling results in sluggish recrystallisation and produces a coarse final grain size. However, the initial as cast microstructure recrystallises at a slower rate than conventional hot band and produces a weaker recrystallisation texture. This can be attributed to the heterogeneous microstructure of the as cast Strip such that, after rolling, nucleation occurs within shear bands and more ill defined sites...

Yu Hao - One of the best experts on this subject based on the ideXlab platform.

Baode Sun - One of the best experts on this subject based on the ideXlab platform.

  • Static Recrystallization Behavior of Twin Roll Cast Low-Carbon Steel Strip
    Journal of Iron and Steel Research International, 2011
    Co-Authors: Zhixiong Xie, Haiyan Gao, Jun Wang, Yonggen Yan, Yuan Fang, Baode Sun
    Abstract:

    Abstract The static recrystallization kinetics of low-Carbon Steel cast Strip was investigated by means of interrupted hot tensile tests. As-cast Strip was reheated and soaked and its austenite grain size was similar to the width level of the as-cast columnar structure. The tests were carried out on Gleeble-3500 thermomechanical simulator. The deformation temperature is in the range of 800 to 1200 °C with strain rate of 0.01 to 1 s −1 . The prestrain is fixed at 0.04 to 0.12, and the inter-hit delay time varies from 1 to 3000 s. Effect of deformation conditions and initial micro-structure on static recrystallization behavior was investigated. The activation energy (Q six ) and Avrami exponent ( n ) of static recrystallization were determined to have 241 kJ/mol and 0.54 respectively by linear regression of the experimental results. A kinetics model was proposed to describe the static recrystallization kinetics in low-Carbon Steel cast Strip. The predicted softening fractions are in good agreement with the experimental results, indicating that the proposed equations can give an accurate estimate of the softening behaviors for the low-Carbon Steel cast Strip.

  • Dynamic Recrystallization Behavior of Twin Roll Cast Low Carbon Steel Strip
    ISIJ International, 2009
    Co-Authors: Haiyan Gao, Zhixiong Xie, Jun Wang, Yuan Fang, Baode Sun
    Abstract:

    Dynamic recrystallization behavior of twin roll cast low Carbon Steel Strip was investigated in this paper in an attempt to provide guiding deformation parameters for the on line hot rolling. As cast Strip was reheated and soaked with austenite grain size similar to the width level of the as cast columnar structure. Tensile test was used and the deformation temperature is in the range of 900 to 1100°C and the strain rates are 0.01, 0.1 and 1 s−1. Activation energy and stress exponent were determined by regression to be 306 kJ/mol and 4.69 respectively. The ratio of critical strain to the peak strain ec/ep is 0.65, and that of critical stress to the peak stress σc/σp is 0.92. Dependence of the peak strain ep on the initial grain size D0 and Zener–Hollomon parameter Z is ep=9.1×10−4×D00.48Z0.13. Kinetics of the dynamic recrystallization and the recrystallized grain size was predicted using models published. The as cast coarse austenite will be dramatically refined after complete dynamic recrystallization under low deformation temperature and slow strain rate according to the predicting results.

C. Page - One of the best experts on this subject based on the ideXlab platform.

  • Microstructural control by secondary processing of Strip cast low Carbon Steel
    Materials Science and Technology, 2001
    Co-Authors: Michael Ferry, C. Page
    Abstract:

    AbstractThe secondary processing of low Carbon Steel Strip produced by twin roll casting was investigated to examine its effect on microstructural development and mechanical properties. The as cast microstructure is predominantly acicular ferrite with regions of bainitepearlite and polygonal ferrite. Deformation at temperatures below Ar1 produces a heterogeneous microstructure with regions of moderately deformed acicular ferrite adjacent to highly deformed regions containing shear bands. Cold rolled and warm rolled Steels show similar behaviour to conventional hot band in that dynamic recovery during warm rolling results in sluggish recrystallisation and produces a coarse final grain size. However, the initial as cast microstructure recrystallises at a slower rate than conventional hot band and produces a weaker recrystallisation texture. This can be attributed to the heterogeneous microstructure of the as cast Strip such that, after rolling, nucleation occurs within shear bands and more ill defined sites...

Rafael Colás - One of the best experts on this subject based on the ideXlab platform.

  • Gravimetric and electrochemical methods to evaluate the performance of corrosion inhibitors for galvanized Steel Strips
    Corrosion Reviews, 2018
    Co-Authors: Mayra Y. Rodríguez-pérez, Rafael Colás, Maribel De La Garza-garza, Facundo Almeraya-calderón, Alfredo Artigas, Alberto Monsalve, F. A. Pérez-gonzález, J. H. Ramírez-ramírez, N. F. Garza-montes-de-oca
    Abstract:

    AbstractCorrosion inhibitors with Cr+6 and Cr+3 are applied on the surface of metals to increase their chemical resistance when they are exposed to severe degradation conditions. For galvanized low-Carbon Steel Strip, these compounds are applied to reduce corrosion mainly during transport operations of this metal. The performance of corrosion inhibitors deposited on the surface of galvanized Steel Strip was evaluated through combined physical and electrochemical modeling. The physical model takes into account direct exposure of specimens to different conditions including simulated marine, industrial and rain environments for periods up to 8 weeks. The efficacy of the experimental method was also evaluated using polarization resistance and gravimetric means. A good correlation between the evolution of the degradation phenomenon obtained directly from the physical model and the electrochemical and gravimetric data was found. The results showed that this method is an effective tool that allows the comparison of the performance of different corrosion inhibitors that could be used to prevent surface degradation of galvanized Steel Strip.

  • Prediction of shape defects during cooling of hot rolled low Carbon Steel Strip
    Ironmaking & Steelmaking, 2004
    Co-Authors: Rafael Colás, L A Leduc, M.a. Neri
    Abstract:

    Shape defects are found in hot rolled Steel Strip when unwrapping tightly wound coils. This problem is particularly acute in thin Strips that were considered to be defect free while processing. A model developed to predict the occurrence and magnitude of such defects in hot rolled low Carbon Steel Strip is described in the present paper. The model assumes that the Strip is free of shape defects as it exits the last stand of a continuous mill, but, as a result of processing conditions, thermal and microstructural gradients are present across the width of the Strip. It is considered that the variation of ferrite and austenite mixture is caused by the chemical composition of the Steel and the actual temperature of the Strip. On cooling to room temperature, the distribution of both temperature and microstructure will cause variation in the local contraction that the Steel is subjected to, and will promote shape defects.

  • Hot rolling of light gauge Steel Strip
    Isij International, 2003
    Co-Authors: Patricio Zambrano, A. L. Delgado, M. P. Guerrero-mata, Rafael Colás, L A Leduc
    Abstract:

    Production of hot rolled thin gauge Steel Strip in a compact six-stand mill was studied by means of mathematical modelling and on site measurements. Data obtained during processing low Carbon Steel Strip ranging from 1.06 to 2.68 mm in final outgoing thickness included speeds, reductions and separation forces at each of the six stands. The mean flow stress during rolling was calculated from the rolling loads, assuming adhesive conditions within the roll-gap, and by means of a mathematical model that accounts for strain hardening and the occurrence of various dynamic restoration phenomena during deformation. It was found that the values of the mean flow stress values, independently of the way they were obtained, varied as a function of both, strain rate and temperature, being possible to derive a unique formulation to describe their behaviour.

  • A model for the hot deformation of low-Carbon Steel
    Journal of Materials Processing Technology, 1996
    Co-Authors: Rafael Colás
    Abstract:

    Abstract The high-temperature deformation behaviour of low-Carbon Steel can be described by the superposition of work hardening and the combination of dynamic recovery and recrystallization. This las mode of restoration takes place once a critical strain, which depends on the strain rate and the temperature at which the test is conducted, is surpassed. Allowance is made for the grain size and the chemical composition of the Steel in order to fit the experimental data. The model is employed to predict the separation forces recorded during the industrial production of low-Carbon Steel Strip in a six-stand continuous mill.