Analysis of Internal Defects Appeared in the Continuous Casting

Abstract

The paper presents the study of internal defects resulting from the continuous casting of steels. The 50 samples were taken from a total of 20 continuously cast bits of different steel grades. The investigation of the causes of internal defects, shown on the analyzed samples, started from the assumption that the secondary metallurgy was performed correctly. The following internal defects have been evident: internal cracks (axial cracks, section cracks), central porosity and marginal punctuation impurities.

Deformation Behavior and Constitutive Equation of 42CrMo Steel at High Temperature

“…The comparison of experimental and predicted data from different models is shown in Figures 6 and 7, respectively. To quantitatively evaluate the performance of the above models, the R-value and average absolute relative error (AARE) value [4] are calculated by Equations ( 6) and (7), and the results are shown in Figure 8. The closer the R-value is to 1, the stronger the predictive ability is.…”

“…Defects deteriorate products' service performance and fatigue life [7]. To control internal defects, researchers proposed many processes such as the soft reduction (SR) process [8,9] and heavy reduction (HR) process.…”

Study Deformability Ecological Steel (41Cr4)

“…Measurements were performed on a metallographic microscope with ocular gradually to increase x 100. The average diameter of the grains was determined in longitudinal and transverse direction, and based on his average grain area was located (S) [15][16][17]. Figure 6 shows some steel microstructures for 41Cr4, picric acid attack, magnification x 100 (size of former austenite grains depending on the temperature, the degree of deformation ε= 45%).…”

“…This technology is advantageous from various points of view: the final product is a part which does not need afterward processing with solid waste result and therefore the specific energy consume is lower, the wear and corrosion behavior is similar to that of classic steels and better than that of sintered steels obtained through mixing iron and graphite; the obtained steels is also a recycling material [5,6,9]. The carbon steel obtained through this new technology is an ecomaterial, energy consumption and reduced environmental pollution [4,8,15]. From an environmental perspective, the steel is durable and 100% recyclable [1, 11, 13, 16, 19 -23].…”

The Role of Powder Used in the Continuous Molding of Alloys

“…It is considered that obtaining a good quality semifinished steel is determined by the way in which the casting powders fulfill the following roles: -ensuring a good thermal insulation at the surface of the steel in the crystallizer, in order to avoid its solidification [6]; -avoiding the oxidation of the steel in the crystallizer; -lubricating the contact surface between the molten steel and the crystallizer wall by maintaining a layer of liquid slag at the junction of the two metals as suggested in figure 2 [7][8][9][10][11][12][13][14][15]; -achieving a homogeneous transport from a thermal point of view, in accordance with the technological conditions and parameters, such as: casting speed, crystallizer size, steel mark, etc . ; -avoiding the incorporation of separate allogeneic materials in the steel crust by entraining them by the liquid slag.…”