Steelmaking Oxygen Probe

Steelmaking Technology - Metallurgy for Dummies

Technology has greatly changed during the last two decades under the pressure of increased demand, new specifications and the need to reduce energy and material consumption.

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. Their respective shares in crude steel production are 70% (BOF) and 30% (EAF). 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. Coke consumption is about 50 kg/t sinter product.

The British steelmaker

70th Steelmaking Conference proceedings, volume 70, Pittsburgh meeting, March 29 - April 1, 1987

High temperature science

Secondary steelmaking, principles and applications

Ironmaking And Steelmaking: Theory And Practice