The Integration of Process and Product Metallurgy in Niobium Bearing Steels

Abstract

A review of the technological integration of both the process and physical metallurgical advancements of value-added niobium (Nb) microalloyed thermo-mechanical controlled process (TMCP) steels have evolved into the development of higher quality steels for more demanding end user requirements. The connection of process and physical metallurgy is evolving through the integration of research that is aimed at improving product quality. However, often the connection of the process metallurgical parameters is not reported, especially with industrial data. The importance of this innovative metallurgical connection is validated by the market demand for reduced fuel consumption, improved quality, and CO2 emissions in both the automotive and construction sectors. This situation has further increased the demand for new higher quality Nb-bearing steel grades. This integrative process/physical metallurgical (IP/PM) approach applies to both low and high strength steel grades in numerous applications. Often, the transition from laboratory melted and TMCP to the production scale is challenging. The methodology, process control, and key production steps that are required during the melting, ladle metallurgy, continuous casting, thermal, and hot rolling production conditions often vary significantly from the laboratory conditions. Understanding the reasons and corrective action for these variations is a critical product development success factor. These process metallurgy parameters for the industrial melting, casting, reheating, and hot rolling of Nb grades are connected and correlated to the resultant microstructures, physical metallurgy, and mechanical properties. These advanced high strength steels are microalloyed with Nb, V, Ti and/or other elements, which affect the austenite-ferrite transformation. Niobium enables the achievement of substantial grain refinement when the plate or sheet is rolled with the proper reheat, hot reduction, and thermal schedule. A recently developed key metallurgical transition is in progress applying this integrative approach with the use of MicroNiobium. A reduction of Mn and C levels with the complementary refinement of the microstructural grain size through MicroNiobium additions improves the robustness of the steel to better accommodate some process metallurgy variations. Applications are evolving in lower strength steels with Nb to achieve complementary grain refinement.

Synergistic Effect of Bioactive Inorganic Fillers in Enhancing Properties of Dentin Adhesives—A Review

“…Niobium is a metal that is used in metallurgy to augment the properties of different metals [ 99 ]. The use of niobium pentoxide (Nb 2 O 5 ) related to dental applications has risen recently.…”

Advances in Microalloyed Steels

“…The present Special Issue on Advances in Microalloyed Steels includes two review papers [1,2] and nine research papers [3][4][5][6][7][8][9][10][11]. In all of them, different combinations of microalloying elements are analyzed in terms of process, microstructure, and mechanical property modification.…”

“…The alternatives in microalloying are clearly reflected in terms of the grades studied in the different papers. Nb is present in many of them [1,2,5,7,8,10,11], alone or in combination with Mo [2,5,10], Ti [8], and V [10]. Two papers deal with Ti-Mo combinations [6,9], and the last two articles analyze the addition of V [4] and Al [3] as microalloying elements.…”

“…Even if some papers cover specific performance problems and optimization alternatives for industrial processing conditions [1,2,7,11], most of the papers deal with more fundamental analyses of the relationship between microstructure and mechanical properties [4][5][6]8,10]. Some papers also analyze the effect of microalloying on hot and cold working behaviors [3,9].…”

Austenite Softening in the Finishing Stage of T.M.C.P. Of High Niobium-Low Manganese Microalloyed Steels

“…This fact was unusual, since the finishing stage had started around 940-970°C, well below the of T nr experimentally determined by a multiple hot torsion test for a similar steel, 1070°C [13], according to the procedure proposed by Boratto et al [14], as shown in Figure 1. It should be noted that the difference between T nr measured in the laboratory and the finishing start temperature adopted in the industrial controlled rolling was advocate its replacement by Nb microadditions, which have been done with good results both in technical and economic terms [2]. Other advantages resulting from the lowering of the Mn content, these already known for a long time, are the reduction of the load of ferroalloys in the ladle and the consequent loss of heat by the liquid steel and lower contamination by P, as well minimization of central segregation intensity in slabs and microstructural banding in the final products [3].…”