Abstract
A method of calculation was studied to determine the amounts of nitides and carbides in the steel to which various carbide or nitride forming elements were simultaneously added. According to the results obtained, the behaviours of these precipitates determined by the calculation were in accordance with thoseexperimentally determined in the specimen held at the temperature of austenite range, such as heating temperature of the slab, normalizing, or quenching temperatures.
As an example, the behaviours of carbides and nitrides in y state of the steel containing niobium and aluminium are determined as follows by calculation.
(1) In the range of carbon content of more than 0.10% and of nitrogen content of 0.006%, which corresponds to the chemical composition of commercial steel, niobium tends to form carbide3 than nitrides.
(2) Only the precipitates of NbC and AIN are formed when carbon contant is more than 0.10% and nitrogen content lies between 0.006 and 0.01%.
