Production of Coiled Rolled Product of Strength Category X70 for Tube Purposes Under Casting and Rolling Complex Conditions

Results are given for industrial approval of production under casting and rolling complex conditions within the composition of a joint metallurgical company of rolled coil for tube of strength category X70 without adding niobium for three microalloying systems (V–N, V–Ti–N, V–Ti). It is shown that in order to prepare rolled coil of strength category X70 without additional specifications according to Charpy and DWWT tests at negative temperature the most suitable steel system is microalloying with vanadium and nitrogen (V–N system).