Publication detail

Thermophysical properties measurement of scale layer on steel substrate using flash method

POHANKA, M. CHABIČOVSKÝ, M. ONDRUCH, T.

Original Title

Thermophysical properties measurement of scale layer on steel substrate using flash method

English Title

Thermophysical properties measurement of scale layer on steel substrate using flash method

Type

abstract

Language

en

Original Abstract

Most of the steel is processed at very high temperature. The hot steel surface is in contact with surrounding atmosphere and reacts with oxygen which is contained in it. Ferrite oxides are formed on surface. These oxides are called scales. Scales form very complex layer on the surface. Sales are mostly porous and composed of various scales such as Wüstit (FeO), Hematite (Fe2O3) and Magnetite (Fe3O4). Steel grades contain various additives, and one of the most common is silicon, which forms Fe2SiO4 (fayalite). Other additives such as aluminum, chrome, nickel, molybdenum form even more complex scales. Although scales form relatively thin layer on the surface it was confirmed that they need to be included in simulations of steel heat treatment as they can significantly change cooling rate due to the Leidenfrost effect during spray water cooling. Only a limited number of publications describing the thermophysical properties of scales can be found. Mainly due to various porosity of scales, which significantly change thermophysical properties, the real properties need to be measured to have accurate data for numerical simulations. One of well-known and accurate method is Flash method. However, this method is used only for samples from one material. Scale to be measured are fragile and cannot be detached from the steel substrate. This contribution describes improved flash method for measurements of thermophysical properties of scale layer on steel substrate (diffusivity, thermal conductivity, and product of mass density and specific heat). Steel sample covered by scales is heated by laser pulse from one side and temperature response is measured by very sensitive infrared sensor on the opposite side. Complex two-dimensional rotationally symmetric numerical model of this measurement is used by two-dimensional inverse algorithm for computing the thermophysical properties of scales. An example of measured thermophysical properties of scale layer formed on high-silicon steel are presented and compared with data published for common steel.

English abstract

Most of the steel is processed at very high temperature. The hot steel surface is in contact with surrounding atmosphere and reacts with oxygen which is contained in it. Ferrite oxides are formed on surface. These oxides are called scales. Scales form very complex layer on the surface. Sales are mostly porous and composed of various scales such as Wüstit (FeO), Hematite (Fe2O3) and Magnetite (Fe3O4). Steel grades contain various additives, and one of the most common is silicon, which forms Fe2SiO4 (fayalite). Other additives such as aluminum, chrome, nickel, molybdenum form even more complex scales. Although scales form relatively thin layer on the surface it was confirmed that they need to be included in simulations of steel heat treatment as they can significantly change cooling rate due to the Leidenfrost effect during spray water cooling. Only a limited number of publications describing the thermophysical properties of scales can be found. Mainly due to various porosity of scales, which significantly change thermophysical properties, the real properties need to be measured to have accurate data for numerical simulations. One of well-known and accurate method is Flash method. However, this method is used only for samples from one material. Scale to be measured are fragile and cannot be detached from the steel substrate. This contribution describes improved flash method for measurements of thermophysical properties of scale layer on steel substrate (diffusivity, thermal conductivity, and product of mass density and specific heat). Steel sample covered by scales is heated by laser pulse from one side and temperature response is measured by very sensitive infrared sensor on the opposite side. Complex two-dimensional rotationally symmetric numerical model of this measurement is used by two-dimensional inverse algorithm for computing the thermophysical properties of scales. An example of measured thermophysical properties of scale layer formed on high-silicon steel are presented and compared with data published for common steel.

Keywords

scales, steel, water, hydraulic, descaling, overlapping, temperature, heat transfer coefficient, surface

Released

28.09.2016

Publisher

Inštitut za kovinske materiale in tehnologije

Location

Ljubljana, Slovenia

ISBN

978-961-94088-0-3

Book

24th INTERNATIONAL CONFERENCE ON MATERIALSAND TECHNOLOGY

Pages from

175

Pages to

175

Pages count

1

BibTex


@misc{BUT131861,
  author="Michal {Pohanka} and Martin {Chabičovský} and Tomáš {Ondruch}",
  title="Thermophysical properties measurement of scale layer on steel substrate using flash method",
  annote="Most of the steel is processed at very high temperature. The hot steel surface is in contact with surrounding atmosphere and reacts with oxygen which is contained in it. Ferrite oxides are formed on surface. These oxides are called scales. Scales form very complex layer on the surface. Sales are mostly porous and composed of various scales such as Wüstit (FeO), Hematite (Fe2O3) and Magnetite (Fe3O4). Steel grades contain various additives, and one of the most common is silicon, which forms Fe2SiO4 (fayalite). Other additives such as aluminum, chrome, nickel, molybdenum form even more complex scales. Although scales form relatively thin layer on the surface it was confirmed that they need to be included in simulations of steel heat treatment as they can significantly change cooling rate due to the Leidenfrost effect during spray water cooling. Only a limited number of publications describing the thermophysical properties of scales can be found. Mainly due to various porosity of scales, which significantly change thermophysical properties, the real properties need to be measured to have accurate data for numerical simulations. One of well-known and accurate method is Flash method. However, this method is used only for samples from one material. Scale to be measured are fragile and cannot be detached from the steel substrate. This contribution describes improved flash method for measurements of thermophysical properties of scale layer on steel substrate (diffusivity, thermal conductivity, and product of mass density and specific heat). Steel sample covered by scales is heated by laser pulse from one side and temperature response is measured by very sensitive infrared sensor on the opposite side. Complex two-dimensional rotationally symmetric numerical model of this measurement is used by two-dimensional inverse algorithm for computing the thermophysical properties of scales. An example of measured thermophysical properties of scale layer formed on high-silicon steel are presented and compared with data published for common steel.",
  address="Inštitut za kovinske materiale in tehnologije",
  booktitle="24th INTERNATIONAL CONFERENCE ON MATERIALSAND TECHNOLOGY",
  chapter="131861",
  howpublished="electronic, physical medium",
  institution="Inštitut za kovinske materiale in tehnologije",
  year="2016",
  month="september",
  pages="175--175",
  publisher="Inštitut za kovinske materiale in tehnologije",
  type="abstract"
}