Investigation of Production Conditions for Ultra-Low Carbon IF-, IF-HS-Steels from Cold-Rolled Product of Different Strength Classes Annealed in Bell Furnaces

Abstract

Possibilities and conditions are studied for preparing cold-rolled batch annealed steels of different strength classes from one chemical composition of ultra-low carbon IF-, IF-HS-steels using cassette technology and annealing in bell furnaces. Regimes and parameters are developed for laboratory modeling of rolled product batch annealing with substantiation of heating and slow cooling schemes. Coldrolled products are obtained with both a low yield strength (below σ_T ≤ 170–180 MPa) and strength class 180 using IF-steels of one chemical composition, in the majority of cases having a relative elongation of more than 50%. Prospects are established of using batch annealing in bell furnaces for production, including cassette technology, of high-quality cold-rolled steel from IF-HS-steels of different strength classes.