7. A method of manufacturing a high strength steel sheet comprising casting a slab of steel comprising, in mass %, C: 0.02
to 0.04%, Si: at most 0.4%, Mn: 0.5-3.0%, P: at most 0.15%, S: at most 0.03%, Al: at most 0.50%, N: at most 0.01%, and Mo:
0.01-1.0%, performing hot rough rolling either directly or after heating to a temperature of at most 1300° C., commencing
hot finish rolling either directly or after reheating or holding, completing finish rolling at a temperature of at least 780°
C., performing coiling after cooling to a temperature of 750° C. or below at an average cooling rate of at least 3° C./second,
heating to an annealing temperature of at least 700° C. and then cooling to a temperature of 600° C. or below at an average
cooling rate of at least 3° C./second, then holding in a temperature range of 250-600° C. for at least 10 seconds, and then
cooling.
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