China AHMA Special Casting Technology Company uses the Danieli special-shaped billet continuous caster to produce the world's largest special-shaped castings. The new 12m arc double-strand continuous caster casts three special-shaped billet sections and a small slab section with a double crystallizer structure, or A four-strand slab is cast using a two-strand continuous casting machine. The continuous caster is fed by 120t BOF at 180t/h (195t/h in the future). In order to match the productivity of the smelting plant, the productivity per stream of the continuous caster can reach 97t/h. In order to save energy, all special-shaped billets should be sent to the section steel rolling mill.
The maximum size of the three special-shaped billets is 1300×510×140mm, and the linear weight is close to 2.7t/h, making it the largest special-shaped casting in the world.
The new continuous casting machine is equipped with advanced Danieli process technology packages, such as Q-INMO crystallizer vibrating table, which adopts no bearing or leaf spring design, and uses "rolling elements" to ensure good mold guidance. Double cylinders Can withstand great vibration mass.
The automation system includes the Danieli liquid core control system, which monitors the aerosol cooling to ensure accurate and even secondary cooling.
The plate mold is composed of a copper plate fixed to a supporting plate, and the combination of gun drilling and flange grooves in the web and fillet area can form an optimal cooling structure.
The plate crystallizer can realize the taper optimization of different areas. The two-dimensional thermomechanical method is used to study the taper of the shaped billet mold; this model uses "moving slices", a layer of transverse section steel undergoes different thermal boundary conditions (ie heat flux) during the process of moving from the meniscus to the mold outlet. Amount).
Because of the complex geometry of the mold, uniform molten steel casting has become a challenge. The design of the immersion nozzle (SEN) plays a key role in the non-turbulent liquid steel flow field to prevent the mold slag from staying. Uniform heat transfer and stable flow conditions.
Danieli worked closely with the refractory supplier "Flow Simulation Team". The team first carried out a series of numerical simulations to determine the flow properties of different casting nozzles based on previous experience and different debugging stages of the factory. In the end, two nozzle designs were selected. W&S is designed to straighten the cast slab with the largest section BB7 and the highest thermal strength. The steel grade group includes steel grades with extremely high thermal strength, and in-depth analysis of steady and non-steady casting conditions, such as head and tail straightening or tundish Quick change.
AHMA has produced a variety of steel products, including microalloyed steel and fine-grained steel. The first heat achieved satisfactory quality and met strict dimensional design tolerance requirements.