1982 Volume 68 Issue 9 Pages 1378-1387
Effects of alloying elements (C, Si, Mn, and P) and continuous annealing conditions (soaking temperature, cooling rate, and over-aging temperature) on strengthening of steels, have been investigated so as to develop a desirable process to produce commercial quality high strength cold rolled sheets for automobiles by continuous annealing.
In subcritical annealing, cooling rate after soaking has no influence on strengthening effects of alloying elements. Degree of strengthening effects is in the order cf P>C>Si>Mn. In case of intercritical annealing, strengthening effect of C is largely influenced by cooling rate after soaking.
Continuous annealing just above recrystallization temperature, which accompanies ferrite grain refining due to subcritical annealing is the most desirable strengthening procedure on the viewpoint of economy. In this case, moreover, the similar strength-ductility balance and the superior bake hardenability to those by other processes can be obtained even after subcritical annealing without over-aging.
