アーク溶接時の冶金反応に関する研究(第1報)

アーク溶融時の脱酸平衡

抄録

Deoxidation equilibriums in Arc melting were studied as the first step in the investigation of metallurgical reactions in arc welding. The iron specimens containing oxygen and some deoxidation alloying elementss were melted under arc using a tungsten electrode in an Argon atmosphere, and these deoxidation reactions were investigated.
The results of the Si, Mn, Si-Mn, V, Ti, Al deoxidations and the oxygen solubility in pure iron are as follows.
(1) Within 100 sec., all the reactions reach the apparent equilibriums.
(2) Being compared with the thermodynamical equilibrium data, the results of the apparent equilibriums of the Si (<0.2%), Mn, V, Ti deoxidations and the oxygen solubility under the same melting condition are almost consistent with the equilibrium data at the same temperature (e.g., corresponding equilibrium temperature 16401670°C at Argon pressure 500 mm Hg, current 500 A). With increased Argon pressure or current, the corresponding equilibrium temperature is increased at the rate of 1015°C/100 mm Hg or 2030°C, /100 A in the case of the oxygen solubility. However, the presence of Mn in the Si-Mn deoxidation is not effective as expected and the Al deoxidation is less active than calculated from the data of equilibrium., It is probalbe that the fact of the latter is caused by the present experimental method.
(3) The Si and Si-Mn deoxidations (Si>0.5%) are very active, and these results can not be interpreted by the SiO₂ forming reaction. It is anticipated that the equilibriums will be controlled by the SiO forming reaction at the constant SiO pressure. This a characteristic phenomenon in arc melting.