Furnace Technology Area

Area Head

Objectives

• To study the physical phenomena involved in the reheating of steel parts inside industrial furnaces, in order to improve the production process by increasing the heating quality and productivity and diminishing the energy consumption and material waste.
• The coordination of furnace related activities that are carried out in CINI departments.

Research areas

Model of the reheating of steel billets prior to piercing in the seamless steel tube manufacturing process

Hefestos System Isotherms in a billet transverse cross section and upper sole of SIDERCA’s rotary reheating furnace, as calculated by the Hefestos model: a) at 1.3 m from the furnace entrance; b) at 42.3 m; c) at 110.5 m (furnace exit)

On-line control The model is used to control the furnace, calculating on-line the thermocouple and cycle time settings for optimal furnace operation

Simulation of steel-tube reheating in the walking beam furnaces that are used in the heat treatments

Tube bend Tube bend at SIDERCA’s TRA2 austenizing furnace. The model was used to study the effect of the loading mode on the maximum temperature difference during the heating process

Model Validation The figure shows the measured values along with those calculated by the model corresponding to the reheating of a 168.3x6.4mm tube at the SIDERCA’s TRA2 tempering furnace

Productivity The model was used to increase the productivity of normalized products at SIDERCA’s TRA1 heat treatment line. The figure shows the old cycle time as a function of the minimum required cycle time calculated by the model for a set of different products of the same grade. Departures from the solid red line correspond to opportunities of improvement that were verified in plant operation and adopted as the new standard

Tube-end reheating Net radiative flux leaving the surface of the tube. Both sides of the pipes are modeled to show the fact that the inner wall of the pipe is almost completely shielded from outside radiation. Net radiative flux is larger close to the ends of the pipe due to the influence of furnace lateral walls (not shown). It is also evident that the radiative flux on the right and left sides of the pipe is smaller than that at the bottom and top due to the reciprocal influence of the relatively cold neighboring pipes

Model of the reheating of slabs prior to hot rolling in the strip production process

Skid marks Isothermal curves for the leading half of the slab. Inside these furnaces the slabs are pushed sideways towards the outlet and supported by four refrigerated skids. The figure shows the “skid marks” generated by the presence of the skids, that undermine the temperature homogeneity

On-line control Mean slab temperatures measured at the rougher exit for a period during which the furnace was controlled by the model. The slab temperatures are represented with green bars and the slab thickness is shown in red. The blue segments indicate the target temperature intervals