| 摘要 |
The invention relates to micro-alloyed steels, in which the carbon/vanadium weight ratio (C/V value) is 0.4 to 1.5, the sulphur content is 0.003 to 0.012 % by weight and the calcium content is 0.001 to 0.02 % by weight. The invention also relates to steel tubes, in particular for structures, for mining and as high-strength tubes which are produced from these micro-alloyed steels. Furthermore, the invention relates to a process for producing these steel tubes, in which a uniformly coarse austenite grain structure is formed in a starting block of an above micro-alloyed steel by heating to a temperature above 1200 DEG C, a recrystallised block having a finer austenite grain structure is then produced by at least 20 % preforming and this block is rolled to the final size by at least 50 % forming in a successively interrupted hot-forming sequence. |
