EXPERIMENST ON DECREASING HYDROGEN CONTENT IN MOLTEN 13% CHROMIUM STAINLESS STEEL

Abstract

It is known that the molten high Cr steel is apt to make blow holes when it is cast, and this is due to its high H content. The authors confirmed this cause by comparing H content of 13% Cr stainless bath melted by are furnace with that melted by high frequency furnace. The forme was very high in hydrogen content and apt to make blow holes, but the latter was not so high and not apt to make them. But it is very difficult to decrease H content of the high Cr steel bath melted by are furnace because of the properties of its melting process and the high Cr steel bath itself.
Therefore the authors attempted to decrease the H content by blowing Cl2 or N2 gas into steel bath, as already applied in light alloy melting. 100kg 13% Cr stainless steel scrap was melted in a 100kg high frequency furnace, and at first H gas blowed in it. After the H content became probably much as that of the 13% Cr stainless steel bath melted by arc furnace, Cl2 or N2 gas is blowed in for some minutes.
The authors made success in decreasing the H content by blowing Cl2 gas in both. N2 gas was not suitable. The mechanical properties of such steel were the same as those of normal 13% Or stainless steel.