| 摘要 |
PURPOSE:To prepare ritriding iron as an N adding agent to be added to a molten iron and steel containing 1.0-10.5% of N by a method wherein iron powder obtained by reducing oxidized iron powder is nitrided by heating within a gas stream such as decomposed ammonia gas or the like. CONSTITUTION:Oxidized iron powder, scale, good quality iron ore ore the like is ground to 10 mesh or less and introduced into a reductive nitriding furnace. The atmosphere within a furnace is replaced to a reductive gas atmosphere such as decomposed ammonia gas, hydrogen gas or CO gas and oxidized iron is reduced to iron by heating to 500-1,100 deg.C. Subsequently, this iron is maintained at 350- 750 deg.C for 2-50hrs. within a mixed gas of nitrogen and hydrogen or decomposed ammonia gas to obtain a nitriding iron containing N; 1.0-10.5wt%. This nitriding iron is prepared as a sintered product or a powdery product due to the height of temp. during reducing reaction and this product is added to pig iron or steel in a molten condition and N content thereof is easily increased to an objective value. |
