Effect of Nitrogen and Other Alloying Elements on the Low-Temperature Brittleness of Steel. III : Nitrogen Fix and Nitrogen in Quench-Tempered Steel

The following have been made clear by examining the effect on the low-temperature brittleness of steel of aluminium and titanium as the elements fixing nitrogen. (1) The effect of nitrogen decreases with the addition of aluminium and titanium ; (2) in the steel containing 0.32% of carbon, AlN lowers a little the pulse value of steel, but has little effect on the transition temperature ; (3) unlike the case of adding aluminium, the addition of titanium slightly raises the maximum pulse value and tends to raise the transition temperature ; (4) when the effect of nitrogen on the low-temperature brittleness of the steel containing phosphorus appears relatively large, the addition of titanium clearly improves the low-temperature brittleness of the steel ; (5) the effect of nitrogen can be observed even in the steel quench-tempered, the effect of nitrogen similar to the case of air-cooling appears on slow-cooling after tempering and the aging phenomenon appears on rapid-cooling after tempering ; (6) in both cases, the transition temperature rises proportionally to the amount of nitrogen content