Oxygen Probe,a cutting edge technology for measuring Oxygen content in molten steel . also it helps to find out carbon content and aluminium content in molten steel.

1. 川惣電機工業株式会社
Kawaso Oxygen ProbeKawaso Oxygen Probe
Kawaso Electric Industrial Co., Ltd.Kawaso Electric Industrial Co., Ltd.
KAWASO ELECTRIC INDUSTRIAL CO., LTD.

2. Oxygen Probe for
Secondary Refining

3. Oxygen Probe OXTOxygen Probe OXT
Oxygen Sensor
Temp. Sensor
Electrode
OXTOXYGEN
TEMPERATURE
PROBE

4. Construction and measurement principle -
1
O2-
O2-
PO2
1
PO2
2
O2-
PO2
1 PO2
2Stabilized
Zirconia
V
E = RT / (4F) ln (PO21 / PO22)
E = RT / (4F) ln (PO21 / PO22)
2O2-
O2
+ 4e-
Stabilized
zirconia
Reference
Electrode
Conductor
On high temperature, oxygen ion (O2-
) can move through stabilized zirconia
(ZrO2), depending on the deference of oxygen partial pressure between
PO2
1 and PO2
2.

5. Construction and measurement principle - 2
Oxygen sensor uses a partially stabilized zirconia as the oxygen-ion conductor
forming an oxygen-concentration cell by placing reference substance on one side
of it and the substance to be measured on the other side of it, whereby the
difference in partial pressure of
oxygen between those two sides is
transduced into a form of EMF.
This EMF (in V) and the measured-
temperature of the cell / bath (in K)
in combine provide formula to
calculated oxygen activity (or called
“oxygen-content”) in that steel bath,
which is termed to be “aO” in the
equations shown in the next page.

6. Equations for oxygen activity

7. Applications for oxygen sensors
At secondary refining facility, oxygen measurement
enables…
 Decision of Amount of Additional [Al]
 Estimation of [Al] in Steel Bath
…examples of measurement are
shown in the next pages

8. Typical Traces of oxygen and temp.
After Treatment
(After Aluminum Addition)
Before Treatment
1578 , 107mV, 332ppm, [%Al]=0℃ 1580 ,℃ － 175mV, 1.48ppm, [%Al]=0.045

9. Example of [Al] estimation
Fig. Relationship between Analyzed and Estimated [Al] from ao
0
10
20
30
40
50
60
70
80
90
0 20 40 60 80
Analyzed [%Al]x1000
Estimated[%Al]x1000
STD=4.4E-3%
Sol. [Al] estimation formula;
log([%Al]x1000)=A+B/T(K)
+C・log(ao(ppm))

10. Comparison in Temp. and Oxygen ppm

11. Typical shape of oxygen probe
Fig. Typical Shape of Oxygen Probe for Secondary Refining Process

12. Specifications
Oxygen Measurement Probe Standard Specifications
Oxygen
Measurement
Sensor
Solid-electrolyte ZrO2 (MgO)
Reference material Mo-MoO2 Cr-Cr2O3
Molten steel electrode Mo Mo or Fe
Measurement
Range
EMF
(electromotive force)
0~600mV -300~300mV
Measurement time
(Response time)
High oxygen range 3.0~3.5 sec. 3.0~4.0 sec.
Low oxygen range 3.5~4.0 sec. 3.0~4.0 sec.