Optimization of Macro Segregation and Equiaxed Zone in High-Carbon Steel Use in Prestressed Concrete Wire and Cord Wire Application

Abstract

In this study, the relationship between macro segregation and the equiaxed zone in high-carbon grades with continuous casting parameters was investigated and optimized at the İsdemir iron and steel plant. The work was conducted for the 1080 quality of the SAE J403 standard. In this study, some parameters, such as casting speed, secondary cooling, EMS current value and EMS frequency value, were examined. When the results of the experiments are examined, it can be observed that the equiaxed zone in the macrostructure decreases significantly with the reduction of the EMS frequency value. The decrease in casting speed and increase in EMS current value caused an increase in the equiaxed zone. The increment in secondary cooling led to a decline in the equiaxed zone. Once the macro segregation results are examined, it can be seen that it is very important to optimize the continuous casting parameters in order to reduce the macro segregation results of—especially—carbon, sulfur and phosphorus elements. It has also been determined that the macro segregation values of carbon, sulfur and phosphorus elements are low in casting conditions where casting speed is low, and the EMS current value and EMS frequency value are high. In addition, macro segregation measurements of manganese, silicon, chromium and vanadium elements are found to be low under similar casting conditions. It is critical to optimize the continuous casting parameters before production, especially in high-carbon grades to be used for prestressed concrete wire and cord wire applications. As a result of the work conducted using the İsdemir billet continuous casting machine for the 1080-grade SAE J403 standard, aiming to optimize macro segregation and the equiaxed zone, the effective results have been achieved by using process parameters of 2.8 m/min casting speed, 360 A EMS current, 5 Hz EMS frequency and low secondary cooling intensity.

Impact of Electromagnetic Stirring Roller Arrangement Pattern on Magnetic Field Simulation and Solidification Structure of PW800 Steel in the Second Cooling Zone

“…Because the center of the liquid pool lacks equiaxed grains to decentralize the enriched liquid, the flow of the residual enriched liquid will gather in the center of the slab. This led to serious center segregation after the solidification process was completed [ 21 , 23 ]. When using S-EMS with 380 A and 5 Hz electromagnetic stirring parameters, on the one hand, the electromagnetic force generated by the traveling wave magnetic field causes the molten steel to flow violently and wash away the solidification front, which homogenizes the temperature at the solidification front of the casting slab and accelerates the dissipation of superheat.…”

The Angular Velocity as a Function of the Radius in Molten Ga75In25 Alloy Stirred Using a Rotation Magnetic Field

“…The aim of simulating the solidification of alloys (like the semicontinuous casting of aluminium alloys or the continuous casting of steels) is to produce a tool that can integrate the planning of the process parameters, which can guarantee a suitable microstructure and good mechanical properties [1][2][3][4][5]. In the continuous casting of steel, magnetic stirring is used worldwide to obtain a microstructure without a columnar zone and central macrosegregation extending across the centre equiaxed zone, refine the grain size, minimise the shrinkage porosity and macrosegregation, and improve the surface quality [6][7][8][9][10][11][12][13][14][15][16][17][18]. The magnetic induction causes a melt flow, and its simulation is complicated and needs correct data, like the ω(B, r) function.…”