The production flowsheet for Ti-Nb Microalloy high strength steel plate is 206 t top and bottom combined blown converter-LF-RH-230 mm slab casting-rolling 3 〜7 mm plate process. Through optimizing the original 0.45 Nh- 0. 015Ti microalloy steel to 0. 070Ti-0. 015Nb microalloy steel has excellent welding and low temperature impact toughness properties and has better comprehensive mechanical properties. Service results show that the 0. 07Ti-0. 015Nb microalloy steel is identical to 0. 045Nb-0. 015Ti microalloy steel
satisfactory to requirement of process and service