Publication detail

Contribution to Deoxidation of Austenitic Steels in a Vacuum Induction Furnace with Carbon

ŠENBERGER, J. PERNICA, V.

Czech title

Příspěvek k dezoxidaci austenitických ocelí uhlíkem ve vakuové indukční peci

English title

Contribution to Deoxidation of Austenitic Steels in a Vacuum Induction Furnace with Carbon

Type

journal article in Web of Science

Language

en

Original abstract

Deoxidation of steel with carbon under reduced pressure is often used for increasing the steel purity. Suitable units for this purpose in foundries are vacuum induction furnaces. Possibilities of increasing the steel purity by deoxidation with carbon in the vacuum induction furnace were studied for the steel for the petrochemistry of specific composition 25Cr/35Ni. The charge composed of the return material only was melted in the air. During melting the charge oxidized and the oxidizing slag formed. Chemical composition of steel, morphology, chemical composition of inclusions in the steel and chemical composition of slag after vacuuming were studied on the basis of samples taken before and after vacuuming. Temperature and oxygen activity were measured before and after vacuuming. Globular inclusions with dominant content of silicon and manganese were observed in steel before and after vacuuming. Contents of total oxygen in steel didn’t change significantly during vacuuming. On the basis of composition of inclusions and measured oxygen activity the activity of Cr2O3 in inclusions was calculated. A slag sample was taken after vacuuming and equilibrium oxygen activity in steel with regard to the Cr2O3 content in the slag was estimated from the slag composition. Equilibrium oxygen activity in relation to the Cr2O3 content in the slag was higher than equilibrium activity measured in the steel. For this reason it is not possible, under the studied conditions, to decrease oxygen content in steel during vacuuming.

Czech abstract

Dezoxidace oceli uhlíkem za sníženého tlaku se používá k zvýšení čistoty oceli. Vhodným agregátem pro tento účel ve slévárnách jsou vakuové indukční pece. Možnosti zvýšení čistoty oceli dezoxidací uhlíkem ve vakuové indukční peci byly sledovány u oceli pro petrochemii o směrné složení 25Cr/35Ni. Vsázka složená pouze z vratného materiálu byla tavena na vzduchu. Během tavení se vsázka oxidovala a vznikala oxidační struska. Na základě vzorků odebraných před a po vakuování bylo sledováno chemické složení oceli, morfologie, chemické složení vměstků v oceli a chemické složení strusky po vakuování. Před a po vakuování byla měřena teplota a aktivita kyslíku. Před i po vakuování oceli byly pozorovány kulovité vměstky s dominantním obsahem křemíku a manganu. Obsahy celkového kyslíku v oceli se během vakuování významně nezměnily. Na základě složení vměstků a naměřené aktivity kyslíku byla vypočtena aktivita Cr2O3 ve vměstcích. Po vakuování byl odebrán vzorek strusky a ze složení strusky byla odhadnuta rovnovážná aktivita kyslíku v oceli vzhledem k obsahu Cr2O3 ve strusce. Rovnovážná aktivit kyslíku vzhledem k obsahu Cr2O3 ve strusce byla vyšší než rovnovážná aktivita naměřená v oceli. Tím bylo vysvětleno proč během vakuování se obsah kyslíku v oceli nemění.

English abstract

Deoxidation of steel with carbon under reduced pressure is often used for increasing the steel purity. Suitable units for this purpose in foundries are vacuum induction furnaces. Possibilities of increasing the steel purity by deoxidation with carbon in the vacuum induction furnace were studied for the steel for the petrochemistry of specific composition 25Cr/35Ni. The charge composed of the return material only was melted in the air. During melting the charge oxidized and the oxidizing slag formed. Chemical composition of steel, morphology, chemical composition of inclusions in the steel and chemical composition of slag after vacuuming were studied on the basis of samples taken before and after vacuuming. Temperature and oxygen activity were measured before and after vacuuming. Globular inclusions with dominant content of silicon and manganese were observed in steel before and after vacuuming. Contents of total oxygen in steel didn’t change significantly during vacuuming. On the basis of composition of inclusions and measured oxygen activity the activity of Cr2O3 in inclusions was calculated. A slag sample was taken after vacuuming and equilibrium oxygen activity in steel with regard to the Cr2O3 content in the slag was estimated from the slag composition. Equilibrium oxygen activity in relation to the Cr2O3 content in the slag was higher than equilibrium activity measured in the steel. For this reason it is not possible, under the studied conditions, to decrease oxygen content in steel during vacuuming.

Keywords in Czech

Vakuová indukční pec, dezoxidace uhlíkem, ocel pro petrochemii, aktivita kyslíku, celkový kyslík

Keywords in English

Vacuum induction furnace, Deoxidation with carbon, Steel for petrochemistry, Oxygen activity, Total oxygen

RIV year

2015

Released

23.04.2015

Publisher

Polish Academy of Sciences

Location

Katowice-Gliwice

ISSN

1897-3310

Volume

15

Number

2

Pages from–to

105–109

Pages count

5

BIBTEX


@article{BUT120442,
  author="Jaroslav {Šenberger} and Vítězslav {Pernica},
  title="Contribution to Deoxidation of Austenitic Steels in a Vacuum Induction Furnace with Carbon ",
  year="2015",
  volume="15",
  number="2",
  month="April",
  pages="105--109",
  publisher="Polish Academy of Sciences",
  address="Katowice-Gliwice",
  issn="1897-3310"
}