A physico-chemical study has been made on the chemical reactions between slags and metals in welding processes using two series of electrodes containing 10% Fe-Al and 5% Fe-Mn, or 15% Fe-Al and 5% Fe-Mn in the coatings as deoxidizers, and the following results were obtained.
(1) Equilibrium index K'
Mn decreases with increasing basicities of slags B
L and Fe-Al contents in the coatings. The relations between K'
Mn and BL are represented by the following equations;
log K'
Mn(10Al, Mn Deoxidation)=-0.047B
L+0.167
log K'
Mn(15Al, Mn Deoxidation)=-0.047B
L-0.013
(2) K'
Al increases with increasing B
L and Fe-Al contents. The relations between K'
Al and B
L are represented by the following equations;
log K'
Al(10Al, Mn Deoxidation)=+0.074B
L+3.175
log K'
Al(15Al, Mn Deoxidation)=+0.074B
L+3.517
(3) K'
SiO2 decreases with increasing B
L, and increases with increasing Fe-Al contents. The relations between K'
SiO2 and B
L are represented by the following equations;
log K'
SiO2(10Al, Mn Deoxidation)=-0.408B
L-0.757
log K'
SiO2(15Al, Mn Deoxidation)=-0.408B
L-0.585
(4) K'
TiO2 decreases with increasing B
L, and increases with increasing Fe-Al contents. The relations between K'
TiO2 and BL are represented by the following equations;
log K'
TiO2(10Al, Mn Deoxidation)=-0.204B
L-1.807
log K'
TiO2(15Al, Mn Deoxidation)=-0.204B
L-1.574
(5) The activity coefficients yMmOn of various oxides in weld slags are represented by the following equations, where yMmOn→1, when B
L→O;
log y MnO=+0.047B
Llog y Al
2O
3=-0.074B
Llog y SiO
2=-0.408B
Llog y TiO
2=-0.204B
L
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