Main trends in the development of slide-gate systems

Abstract

This article examines the three stages in the development of slide-gate systems. The modern slide gate is characterized by the presence of elastic elements and reliable fastening of the plates. Different methods are discussed for securing the refractory plates in the carriage of the slide gate. Reliable operation of the gate is provided by the drive and auxiliary elements designed with allowance for the specific features of the casting of metal with the use of slide gates. Hydraulic drives have proven to be the most effective drives in Russia and abroad. The article also discusses the shapes of refractory slide-gate plates that help reduce crack propagation and make the plates more reliable in service. The latest generation of slide-gate plates is now in wide use, these plates being made with carbon-based, oxygen-free, or cermet binders.A slide-gate system is a complex of production equipment, auxiliary equipment and refractory elements that allows metal to be cast through a slide gate. The system includes slide gates for steel-pouring ladles and tundishes, a drive mechanism and feed devices, and auxiliary equipment and materials (molds, mortars, fillers, etc.). The introduction of slide-gate systems has been characterized by three stages of development. First Generation of Slide-Gate Systems (1965 -1980)The refractory systems of this generation allowed the casting of just a single heat [1]. The slide gate -a massive structure weighing 500 -1000 kg -was made in auxiliary shops. The gate designs were of the "rigid" type and the plates comprising the gate were pressed against one another by bolts. The plates were installed in the gate with the use of a mortar. They were serviced in special shops, and it was necessary to maintain a large stock of reserve gates. The service life of a gate was 70 -100 heats. It took more than 2 h to replace the refractories in the casting unit. Each metallurgical plant developed its own design of drive (hydraulic, pneumatic, or electrical) without regard for the details of the casting operation itself.The characteristic features of the plates used for the first generation of slide gates were as follows:-the use of plate materials with a single-component composition based on fused or sintered periclase, mullite, corundum, zircon, or other material;-the use of unconcentrated raw materials; -the use of a ceramic binder; -partial alloying of the plate material with refractory oxides to improve certain properties (Cr 2 O 3 was used to reduce the wettability of the surface of the metal, ZrO 2 was used to improve heat resistance, etc.); -impregnation of the plates with carbon-bearing liquids (coal-tar pitch, liquid bakelite, etc.); -the use of a coarse porous structure in which 70 -75% of the pores were 20 -30 mm in size and 20 -25% were smaller than 1 mm; the presence of individual pores with a size in the range 40 -70 mm contributed to significant wear of the plates;-the absence of metal casings and the use of a system of mortars to join the refractories together.Most of the plates in the ...

Enhancing the thermal shock and corrosion resistance of low‐carbon Al2O3–C refractories: The role of h‐BN composite powder

“…Al 2 O 3 -C refractories are widely used as slide gate plate refractories today. 1,2 Generally, a high graphite content (8-20 wt.%) is necessary to ensure excellent resistance to slag corrosion and thermal shock. [3][4][5] However, high content carbon is easily oxidized deteriorating the thermal shock and slag corrosion resistance of the refractories.…”

“…Al 2 O 3 –C refractories are widely used as slide gate plate refractories today 1,2 . Generally, a high graphite content (8–20 wt.%) is necessary to ensure excellent resistance to slag corrosion and thermal shock 3–5 .…”

Coil Design in Electromagnetic Induction-controlled Automated Steel-teeming System and Its Effects on System Reliability

“…[1][2][3] The slide gate nozzle is still the main apparatus of a conventional ladle-teeming method. [4][5][6][7] The free opening rate of this method is only about 98% and the nozzle sand filling the upper nozzle can contaminate the molten steel. [8][9][10][11][12] Aimed at resolving these problems, a new method [an electromagnetic induction-controlled automated steel-teeming (EICAST) method] was proposed by Qiang Wang [13][14][15] et al The basic idea of the method is using an induction coil located in the nozzle brick to melt part or all of the new well-packing material (i.e., Fe-C alloy with a similar composition of molten steel), which replaces the conventional nozzle sand, and to achieve smooth automated steel teeming.…”