PURPOSE: To produce the cold rolled steel sheet for deep drawing having high baking hardenability and deep drawing property by using an extra-low carbon steel having the specific compsn. which is regulated in the contents of S and N and is further added with B and Ti, and optimizing the cooling patterns in recrystallization annealing.
CONSTITUTION: The steel blank material which contains 0.0005 to 0.006wt.% C, ≤1.5% Si, ≤1.5% Mn, 0.005 to 0.10% Ti, 0.0004 to 0.0015% B, 0.005 to 0.100% Al, ≤0.15 P, ≤0.0030% S, and ≤0.0040% N, satisfies the conditions under which the effective component Ti(Ti*) given by the formula Ti*%=([Ti%]-48/14[N%]-48/32[S%]) attains the range of 4 to 20 times the [C%] at ≤0.0050% total of the contents of the S and N, and further contains the balance iron and unavoidable impurities, is subjected to hot rolling then to cold rolling. This steel sheet is thereafter heated up to a temp. range of 730 to 900°C at ≥1°C/S heating rate. The steel sheet is thereafter subjected to the recrystallization annealing under the conditions under which the steel sheet is rapidly cooled at ≥20°C/S cooling rate down to ≤550°C temp.
TOGASHI FUSAO
ABE HIDEO
SUMIYAMA KOZO
| JPS61276962A | 1986-12-06 | |||
| JPS5938337A | 1984-03-02 | |||
| JPS61276928A | 1986-12-06 |
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