Influence of hot-core heavy reduction rolling on microstructure uniformity of casting billet

Abstract

The hot-core heavy reduction rolling (HHR 2 ) technology is a solidification end reduction technique to enhance the quality of steel. In the current study, the Cellular Automata (CA) calculation is applied to investigate the casting process before HHR2 and the HHR2 dynamic recrystallization (DRX) process. The experimental data and calculation data are compared to verify the accuracy of the method and models. Afterward, based on the actual casting process, the solidification structure in the thickness direction of a billet is calculated, and the influence on the HHR2 grain size of various conditions, such as rolling speed, deformation temperature, and reduction strain, is simulated. Furthermore, based on the fixed HHR2 process, the influence of different superheats, casting speeds, and cooling conditions on the core-surface temperature schedule and the grain size before and after HHR2 deformation is calculated. Finally, the process optimization trend to produce high-carbon bearing steel billet is obtained.

Homogenization Path Based on 250 mm × 280 mm Bloom under Mixed Light and Heavy Presses: Simulation and Industrial Studies

“…In order to meet the GB/T4162A [29] level of flaw detection requirements for bars with a diameter of ≥φ70 mm, it is necessary to cooperate with the long high temperature diffusion time and high compression ratio rolling of the casting billet. This process can affect production efficiency and the casting of billets when expanding the specifications of material production [30]. Based on the continuous casting solidification cooling contraction model established previously, a large square billet process model under heavy pressure was developed.…”

Thermo-mechanical analysis of the flange in a Billet continuous casting machine based on limited temperature measurements

“…Obviously, due to the different casting conditions such as the dimensions of the mould, casting speed and cooling conditions, this profile provides an estimate of the average heat flux, which was responsive in most casting conditions [16,17,19]. The model presented by Savage can be reformulated in the form of Equation (7), in which the time is substituted by the ratio of displacement to the melt velocity, namely, q(MW/m 2 ) = 2.68 − 0.335 t √ = 2.68 − 0.335 z(mm)/v c (mm/s) .…”

“…According to Equation (7), at the meniscus level or z = 0 mm, the heat flux value is equal to 2.68 MW m −2 .…”

“…According to Ref. [7], the emissivity coefficient is considered 0.8 for the steel melt and parts. The ambient temperature is also assumed to be 35°C.…”

“…The time duration which takes the melt to traverse from the meniscus level to the output is referred to as the dwell time. The derivation of the foregoing function with respect to the dwell time results in the local heat flux profile, which can be used as a boundary condition of the corresponding heat transfer differential equations [7][8][9].…”