A Study on the Deoxidizing Effect of Mn and Si in Flux (Report 2)

The relationship between the composition of flux on one hand and Mn and Si on the other

Abstract

Flux can be satisfactorily improved by including Mn and Si in it as deoxidizing agents. But the deoxidation effects differ according to the different compositions of the solvents used.
On different kinds of flux, experiments have been conducted in this connection under the following conditions :
1) When the flux containing charcoal powder with C as its major component has been compared with one containing ilmenite and dextrin ;
2) When only the solvent of CaO and A1₂O₃ is esed ; and
3) When SiO₂ or MnO₂ is-added to the above solvent.
The following are the results ascertained by such experiments :
When C on one hand and Mn and Si on the other co-exist. the amounts of C and Mn in the mild steel arc welds go up and an avderse effect takes place ; ilmenite and organic substanece (dextrine) give a favorable effect on deoxidation ; and Mn and Si are effective deoxidation ; and Mn and Si are effective deoxidizers even when the CaO-A1₂O₃ slag is basic.
It has also been confirmed that, when SiO₂ and MnO₂ are added to the solvent containing deoxidation agent, there is a deteriorating trend in the quality of mild steel arc welds as the amount of such addition increases above a certain limit.