Surface Evolution and Coatability of Low Density Steels

Lead Research Organisation: University of Warwick
Department Name: WMG

Abstract

RESEARCH THEME - Manufacturing of the Future - Materials Engineering , Metals & Alloys

Project Description
A high amount of Al (~7 wt%) and Mn (~6 wt%) in low density FeMnAlC steels make them very different from the conventional steels. The highly alloyed Al and Mn particularly influences the ability of galvanising because of the formation of more stable (Mn,Al)O type oxides. Therefore, the coating ability of FeMnAlC steels will be different from the conventional steels. In addition, the Al in the steel may also react with N, which can be present as an impurity in the bulk steel or in the gas-atmosphere in which the steel is cooled, re-heated and rolled. Aluminium nitride precipitates could affect the coating ability and result in detrimental mechanical properties. This project aims to investigate the surface microstructure and its effect on coatability in ferritic and duplex LDS alloys with composition ranges being Al 2 to 10 wt% and Mn up to 6 wt%. Specific objectives are:
To develop a fundamental understanding of the selective oxidation behaviour of low density steels with high Al and low to medium Mn in annealing atmospheres.
To understand the formation mechanism of nitride inclusions in annealing atmospheres.
To investigate the effect of the selective oxides and nitride inclusions on the coating behaviour and surface quality
The outcome of the project will be the gained knowledge of the surface evolution in high Al steels under conditions relevant to industrial conditions. This should aid in the strategic goal for developing coated LDS.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509401/1 30/09/2015 25/02/2022
1692164 Studentship EP/N509401/1 01/02/2016 30/04/2020 Jack Luke Isaacs
 
Description The oxidation behaviour of dual phase low density steel (Iron+Aluminium+Manganese rust) has been suggested by the finding of this project as being subject to intrinsic solute concentrations and their effects on local grain boundary oxide formation. (Steel is made up of crystal grains, separated by a grain-boundary, in dual phase steel two different types of grains can be next to each other, these may contain different amounts of Aluminium and Manganese. The establishment of an grain-boundary oxide can shape the direction of further oxygen penetration and subsequent oxidation.

This project is still on-going but this effect has been seen and is subject to further verification.
Exploitation Route This project already has a "successor". This project focuses on the internal oxidation (below the surface of the steel, inside it), a recently new project here is focusing on similar aspects but a focus on the external oxidation (on the surface). These two behaviours are linked, but the characterisation of the sub-surface behaviour was believed to be necessary to complete first.
Sectors Construction,Manufacturing, including Industrial Biotechology,Transport