Development and Production of Niobium-Titanium Microalloyed Steels at Gallatin Steel
In this paper, the development and production of nfiobium-titanium containing High Strength Low Alloy (HSLA) steels at Gallatin Steel Company (GSC) is described. The concept of High Temperature Conventional Controlled Rolling (HTCCR) was developed to hot roll 65 mm thin slabs at elevated temperatures. The HTCCR process was accomplished by using the optimal combination of niobium (Nb) and titanium (Ti) to raise the no recrystallization temperature (Tm), so that the critical deformation of austenite below the Tm temperature can be performed at a higher processing temperature, followed by an intense Accelerated Controlled Cooling (ACC) at cooling rates ranging from 20 ℃/see to 60 ℃/see. The use of HTCCR-ACC process has attained very fine ferrite-bainite microsturctures, con-sequently resulting in yield strengths that have consistently achieved in excess of 550 MPa (80 KSI), while maintaining high toughness. The development of Gallatin Grade 100 (687.5 MPa minimum yield strength) will be discussed as well. The synergetic effect of titanium and niobium on mechanical properties will be discussed in terms of steel compositions and TMCP processing conditions in conjunction with their effects on forming as-cast equiaxed grain structures of thin slab,improving niobium solubility in austenite, controlling austenite grain coarsening during slab reheating, refining austenite grain during hot rolling, and enhancing post-deformation transformation of austenite-to-ferrite with optimal precipitation strengthening.
thin slab recrystallization austenite and ferrite grain refinement precipitation strengthening controlled rolling accelerated cooling titanium niobium
L.K.Chiang
Gallatin Steel Company 4831 U.S.Highway 42 West, Ghent, Kentucky 41045-9704 USA
国际会议
2009年薄板坯连铸连轧国际研讨会(TSCR 2009)(2009 International Symposium on Thin Slab Casting and Rolling)
南京
英文
335-347
2009-05-13（万方平台首次上网日期，不代表论文的发表时间）