Heat transfer, oil lubrication and mould tapers in steel billets casting machines

Sanjay Chandra
1992
This study examines in detail the factors that influence mould-billet interaction and heat transfer during the continuous casting of steel billets. In an extensive three-year project, major industrial trials were held in three Canadian steel plants involving in each case an operating mould instrumented with arrays of thermocouples to record mould wall and mould cooling water tem peratures. Additionally, load cells were installed between the mould housing and the oscillator table to record
more » ... billet interaction. Linear variable displacement transducers were attached to the mould wall in order to monitor mould displacement. Measurements were made under different casting conditions - steel grades, types and flow rates of lubricating oils and mould tapers - and were recorded on a computer controlled data acquisition system. The liquid steel surface in the mould was also filmed during casting. Two existing mathematical models of the mould were modified and used to calculate the axial heat flux profiles and the dynamic distortion of the mould during service. A two-dimensional, finite-difference, heat-flow, mathematical model of the billet was developed to simulate solidifi cation and shrinkage as a function of axial position in the mould. The coefficient of thermal con traction of steel was estimated as a function of steel carbon content and temperature from experimental data in the literature Ofl the lattice parameter of and ' unit cells; this was particularly important to model the shrinkage of low-carbon steels. It has been shown that in theory, the low carbon steels (C <0.15%) should experience the largest contraction due to δ- γ phase transformation; but in practice, they shrink less because heat transfer to the mould is low compared to higher carbon grades. A computer programme was developed to analyse the load cell response as a function of mould displacement. Finally billet samples collected during the trials were metallographically examined to study the different aspects of the solid [...]
doi:10.14288/1.0078515 fatcat:vwreuagkzbh67epgi3vwawb4ci