Converter steelmaking technology

The upshot is that you can produce high-quality materials at low cost. More Information. Full automatic infrared all-in-one ladle recognition system. Water leakages detection for Submerged arc furnaces. Better process with automatic tapping. Energy-efficient automation for dedusting plants. Integrated and automated ladle management. Comprehensive management of sampling and analysis results. Digital counterpart of a customer-specific plant. Solution for smooth process flow and constant high quality.

Always at your side, quickly and dependably, worldwide. New state of the art hardware, latest development software. Safeguarding plant lifetime.

Systematic analysis of data in an electronic form. Production planning and scheduling for all production units in the plant. Production efficiency has been improved by increasing the melt capacity of furnaces, implementing on-line computer control modules, and introducing new technologies, such as the combined blowing process for LD Linz Donawitz converters, the Ultra High Power UHP electric furnace, the ladle steelmaking processes and continuous casting.

In both routes the process consists of producing refined iron to which is added the required alloying elements to produce the finished steel specification. High production rates and low impurity steel production give a dominant role to the first process route. Low energy costs and an ample supply of recycled scrap ensure a competitive market share for the second process route, especially when using the UHP furnace.

Before casting, the steel can be refined in the ladle by various processes according to the specification with respect to its deoxidation state, inclusion content and level of phosphorus, sulphur, nitrogen and hydrogen. At the same time, its content of carbon, manganese and microalloying elements such as niobium, vanadium and titanium can be adjusted. This process step is generally referred to as Secondary or Ladle steelmaking. During the last step of steelmaking, the steel is cast either into slabs, blooms or billets on a continuous casting machine or into ingots, depending on the final product.

Flat products and light shapes are normally produced from continuous cast feedstock, whereas heavy beams and plates are more likely to follow the ingot route. The iron feedstock of the blast furnace is the sinter, which is produced in the sinter plant.

In the sinter process, a mix of iron ore fines, lime and coke almost pure carbon is charged in a 45 cm thick layer onto a moving conveyor Dwight Lloyd process and partially melted to form a porous mixture of iron oxides and gangue.

The blast-furnace is a shaft type furnace operating by the counterflow technique : the descending burden of sinter and coke, charged from the top of the furnace, is heated and reduced by the combustion gases ascending from the tuyere zone where a hot air blast is injected to burn C to CO.

The iron oxides FeO, Fe2O3 and some of the elements present in the gangue of the sinter are reduced by CO gases to produce hot metal. The high permeability of the sinter and the even distribution of the charge produced by revolving chutes help to improve productivity of the blast furnace. Below the tuyere zone, where the temperature is highest, the molten material collects on the furnace hearth where the liquid iron pig iron separates from the slag by difference in density.

The slag and liquid pig iron are tapped from separate tapholes. The tapped slag is granulated by water jets and removed for use in other products including road construction materials, fertilizers, etc. The liquid pig iron hot metal is tapped into ladles or torpedo cars capacity: - t and conveyed to the steel plant for refinement and conversion into steel. Sulphur removal from the melt needs low oxygen activities. Desulphurization is therefore achieved in the hot metal by injection of calcium carbide fluxes to form calcium sulphide CaS or fluxes containing metallic magnesium to form MgS and CaS.

The basic oxygen furnace or LD converter originating from the Linz-Donawitz process started in is based on oxygen injection by a lance into the melt of hot metal. Scrap and lime are charged into the converter to cool the melt and remove phosphorus, silicon and manganese.

The converter is lined with dolomite or magnesite refractory which best resists erosion by slag and heat during oxygen blowing. The life of a converter lining is about to heats. The oxygen burns out the carbon as carbon monoxide CO and carbon dioxide CO2 gas which is collected in the chimney stack and cleaned of its dust Fe, and lime particles, etc.

As these oxidation reactions are highly exothermic, the process needs cooling in order to control the temperature of the melt. This cooling is done by charging scrap recycled plant and mill scrap and by adding iron ore during the blowing process. Basic Oxygen Furnaces Flow Chart. The oxygen blowing takes 15 to 20 minutes, regardless of the size of the converter 70 to t because the oxygen flow rate of the lance is adjusted to the melt weight.

The charging and discharging of steel and slag, including sampling for temperature and analysis of the melt, extends the tap to tap time of a converter to 40 - 60 minutes. The process is characterized by high productivity and steel of low impurity content.

The steel is tapped to the ladle through a taphole by tilting the furnace. During this operation ferro-alloys for control of the steel composition are added to the ladle. A major development in the oxygen lance blowing technique, known as Lance Bubbling Equilibrium LBE was developed in the mid-seventies and has been widely adopted.

Neutral gas, typically argon, is injected through permeable elements in the bottom of the converter, stirring the melt and slag. This significantly increases metallurgical efficiency lower Fe losses and lower P content , productivity, and the heat and mass-balance of the process cost reduction.

In the electric arc furnace process, the cold metallic charge, mainly scrap, is melted by the energy of electric arcs generated between the tips of graphite electrodes and the conductive metallic charge.

The three electrodes and the furnace roof are raised and swung away from the furnace shell to allow the charging of scrap. The electrodes maintain the arc in accordance with the voltage and current level selected to produce the desired power input at the desired arc length for melting and refining.

As the noise generated by the arcs is high during the melt-in-period, with levels up to dBA, special protection is provided to the operators cabin and the furnace has a special enclosure.

The three phase alternating current is supplied by the low voltage side - V of a high power transformer. These furnaces have an inner diameter of 6 to 9 metres with a capacity of to tons of steel. The tap-to-tap time for these furnaces is 90 to minutes. The traditional role of the EAF process is producing alloy, tool and carbon steels, and it has been extended by the UHP furnace to mass steel production. Thus, the concept of the Mini-Mill was born.

As the size and productivity of the furnace increased, the operation of continuous casting for billet and bloom production became possible. Flat products specification, however, require low residual impurity levels and even higher production rates which cannot be satisfied by the UHP-furnace. Pellets and sponge iron of higher price have to be used for critical steel grades to control the level of injurious elements, i. The traditional high power furnace produces high quality carbon and alloy steels by the two slag technique.

After melt down of the scrap charge, a first oxidizing slag removes the elements P and Si and reduces carbon to the required level. After deslagging, a second basic reducing slag is formed to lower the sulphur and oxygen contents and the steel composition is adjusted by ferro alloy additions.

The UHP furnace operates with only a lime based oxidizing slag. The melt down of the scrap charge is accelerated by the use of oxy-fuel burners positioned to reach the cold spots of the large hearth furnace. Oxygen lancing and carbon additions are used to make a foaming slag which yields better energy input from the arcs and improves dephosphorization. After this period, the melt is discharged by a taphole. Whilst a typical integrated i.

As EAF steelmaking technology has improved in recent years with high quality steels are availability for EAF steelmakers. The difference in capital costs nonetheless means that EAF steelmaking is likely to grow proportionately more than BOF steelmaking in the coming years. The trend means that traditional BOF steelmakers such as US Steel are increasingly faced with important decisions concerning their choice of future steelmaking process route. In , Air Products started an on-site gas supply concept to the steel industry and now its comprehensive range of industrial gases and cost efficient technologies can help users save money throughout their operations.

The on-site gases supplied by Air Products are used in Guofeng Steel's blast furnace and basic oxygen furnace for iron and steel making. The Basic Oxygen Furnace Steelmaking is one of the top adaptable processes in today's steel manufacturing process. Hence the supporting industries in the form of equipment suppliers, maintenance and services vendors have a large untapped market available in the global market. Thank you for your interest in publishing article with Steet Technology.

Our client success team member will get in touch with you shortly to take this ahead.