| 摘要 |
<p>The invention relates to the manufacture of steel having high strength, toughness and weldability, in the as-rolled condition with a structure of bainite or bainite and ferrite.
<??>The steel is heated within a range of 1000 DEG C, rolled with a reduction amount of not less than 60% at a temperature of not more than 900 DEG C, the rolling finishing temperature is within 640-850 DEG C, and then the steel is cooled to lower than 550 DEG C with a cooling rate of 15-40 DEG C/sec.
<??>The steel contains in wt. %:
C : 0,005 - 0,12
Si : not more than 0,6
Mn : 0,6 - 2,2
S : not more than 0,005
AL : 0,005 - 0,08
Nb : 0,01 - 0,08
B : 0,0005 - 0,002
Ti : 0,004 - 0,03
N : not more than 0,007
Fe : Balance
and satisfying the expression
- 0,01 % </= Ti - 3,4 N </= 0,002 %
optionally the steel may contain at least one element from the group :
V, Ni, Cu, Cr, Mo, Ca and rare earth metals. </p> |
