1969 Volume 38 Issue 10 Pages 1098-1105
The authors have investigated the effect of C, Cr and B addition on the gas contents and the formation of blowholes in deposited metals by non shielded arc welding process with flux cored wire.
Moreover, in this paper, they have theoretically discussed the phenomena of blowhole formation in the deposited metals of multicomponent system from a standpoint of chemical metallurgy.
The results of this investigation are summarized as follows:
(1) The contents of oxygen and nitrogen in the deposited metal are decreased by the increase of C and B therein, but increased by the increase of Cr.
(2) The total volume of blowholes in deposited metal decreases with the increase of Cr and B, while the effect of C addition on the occurrence of blowholes is not so clear.
(3) In explaining the mechanism of blowhole formation, it is easier to explain it by means of the product of activity of C and oxygen, ac⋅ao and activity of nitrogen, aN than by means of the contents of oxygen and nitrogen. The blowhole formation in defosited metals which are fully deoxydized through B is more affected by aN than ac ac⋅ao
(4) The critical values of ac⋅ao and aN for the blowhole formation are obtained as ac⋅ao≅2×10-3 and aN≅4×10-2.