Estimation of Internal Cracking Risk in the Continuous Casting of Round Bars

Abstract

An internal cracking indicator is designed to quantify the risk of hot tearing in the continuous casting of round billets. For this purpose, the tensional state of the bar is acquired by implementing a thermo‐mechanical model that uses a steel material law calibrated with hot tension tests. The cracking indicator is then applied to the phenomenon of diametral pinch‐roll compression. Critical combinations of casting speed and steel carbon content are defined to estimate the cracking risk. At last, macro‐etching is applied on industrial bars in order to reveal internal cracking, which is then compared to model results to assess its predictability. Influence of pinch‐roll pressure and roll shape on the cracking risk is also analyzed.

Review on Modeling and Simulation of Continuous Casting

“…Surface shape problems that have been studied with thermalmechanical computational models include deep oscillation marks and transverse depressions, [151,154] longitudinal depressions, [165,174] off-corner gutters, [174] rhomboidity in square billets, [175] ovalization of round billets, [35,176] and bulging in large blooms and slabs. [3,166,177,178] Unless they are extreme, the shape problems themselves are less important than the cracks and macrosegregation problems that often accompany them.…”

“…A few recent studies have evaluated the accuracy of different hot tearing criteria by modeling lab experiments, which deform a solidifying steel ingot . Specific types of hot‐tear crack defects have been the focus of several successful modeling studies in continuous casting of steel, The microstructure greatly affects hot tearing, as columnar structures that predominate just beneath the strand surface are more susceptible than equiaxed structures, but models rarely include this . On the microscale, models are just beginning to tackle the detailed hot tearing phenomenon that involves steel dendrites pulling apart when interdendritic fluid flow is too constrained.…”

Internal Crack Prediction of Continuous Casting Billet Based on Principal Component Analysis and Deep Neural Network

“…Han [14] proposed an analytical model to calculate the strain acting on the solidification front caused by bulging, bending, straightening and roll misalignment, and used the critical strain obtained from the experiment as the criterion to predict cracks in continuous casting slab. Poltarak et al [15] established a thermal-force finite element model for the continuous casting of round billets to calculate the stress acting on the solidification front to evaluate the internal crack risk under different casting conditions. Other scholars have also conducted similar studies to evaluate crack risk [16,17].…”

Rational Distribution of Surface Cooling Intensity for a Round Continuously-Cast Billet in Secondary Cooling Zone

“…An important task in preparing high quality product is organization of a continuously-cast billet secondary cooling regime. In many works [1][2][3][4][5] it is substantiated that disruption of temperature and rate regime parameters in the secondary cooling zone (SCZ) of a CBCM may serve as a reason for formation of a whole number of billet defects. In [6] in order to resolve the problem of maintaining ingot surface temperature indices in areas of the effect of section cooling [7] a method has been proposed for predicted control.…”