Compensation Control Model of Superheat and Cooling Water Temperature for Secondary Cooling of Continuous Casting

Yang

et al. 2014

JOM

In this article, the formation mechanism of transverse corner cracks on a lowcarbon steel continuous-casting slab was investigated. The factors influencing the transverse corner cracks were discussed. The hot ductility of the lowcarbon steel within 600°C and 1250°C was detected using a thermal simulator Gleeble 1500 (Dynamic Systems, Inc., Poestenkill, NY) to determine the embrittling temperature range of the steel. The temperature of the slab varied with time, especially at the slab corner, and it was calculated and discussed. It was found that transverse corner cracks were generated on the ferrite films along grain boundaries, and there was little decarburization layer near the cracks. According to the calculated temperature at slab corner, the cooling water flow rate and cooling strategy were optimized by adjusting the cooling water flow rate at each spray cooling zone to avoid the embrittling temperature range at the bending and straightening segments of the caster. As a result, the transverse corner cracks were successfully weakened.

Section: Boundary Conditions and Parametersmentioning

confidence: 99%

Control of Transverse Corner Cracks on Low-Carbon Steel Slabs

Yang

et al. 2014

JOM

“…1 Controlling the increment of water flowrate for each cooling loop based on the online feedback temperature Q TC,i (t) is the key to control the strand temperature during steel continuous casting process. It is a feedback control for the secondary cooling loops before the control point, but a feed forward control for the cooling loops after the control point.…”

Section: Model Formulation Of Online Temperature Control System Onlinmentioning

confidence: 99%

Novel online temperature control system with closed feedback loop for steel continuous casting

Long

Chen

Ironmaking & Steelmaking

et al. 2011

Based on a basic water cooling model, a novel model with closed feedback loop was developed for online temperature control system (OTCS) to control the strand surface temperature online during steel continuous casting process. The OTCS considered the temperature delay to the casting speed and water flowrate and combined the feedback control model with feed forward control model for the control of secondary cooling water. The online feed forward control with the temperature of molten steel in the tundish and the temperature of cooling water was also considered. A fine adjusting temperature region and an optimal temperature region were applied to the OTCS to avoid big temperature fluctuation during control process and to shorten the adjusting time. A single point OTCS was applied to a slab continuous caster, showing that the slab surface temperature was well stabilised at the target temperature under the control of the OTCS in continuous casting process. During tundish change or big variation of casting speed, the low slab surface temperature could be quickly controlled to the target temperature again by the OTCS within 7 min. The industrial application indicated that the OTCS could reduce the slab surface cracks and aid in increasing productive efficiency in continuous casting.

“…18) Then the calculated temperature distribution is transferred to rolling model as the initial conditions. The rolling model is created by using ABAQUS/Explicit to calculate the stress and strain fields in the billets with soft reduction.…”

Section: Soft Reduction Modelmentioning

confidence: 99%

Application of a Corner Chamfer to Steel Billets to Reduce Risk of Internal Cracking during Casting with Soft Reduction

et al. 2014

ISIJ Int.

In order to get the brittle temperature range for internal crack, the solidification phase transformation model is established and LIT and ZDT are calculated. Then the fully coupled thermo-mechanical finite element models are developed using the commercial software ABAQUS to investigate stress and strain states in the brittle temperature range of the chamfer billets during soft reduction. The relation between chamfer angle and maximal principal stress, as well as equivalent plastic strain is analyzed, and the influence of chamfer angle of billet on the internal crack is studied. The results indicate that the maximal principal stress and the tensile stress decrease with the increase of chamfer angle. Reducing the soft reduction can lower the stress and strain in the brittle temperature range. It can be obtained that the larger reduction effect and lesser internal crack risk by adjusting the chamfer angle of the billet.