On the dependence of strength of low-carbon lowalloy steels on the cooling rate

The foilowing expression: σsub(i)=σsub(max)-(σsub(max)-σsub(min))exp[-kvsup(n)] is suggested to describe a dependence of strength rameters of low-carbon low-alloy steels (hardness, tensile strength, yield strength etc.) on the cooling rate. The n coefficient determines variations of strength during the change of conditions of austenite structure formation (effective area of austenite grains surface) under the action of thermomochanical treatment and also characterizes steel hardening capacity in accordance with n=4vsub(max)sup(-1/2) expression. Using the known expression of strength dependence on cooling rate it is possible to determine corresponding changes of sizes of ferrite grains, bainite and martensite edgings from a graphical form of αdetta/dv=ddelta/drhodrho/dldl/dv derivative representation