ELECTRIC ARC FURNACE
STEEL PLANT

SCRAP SORTING

Scrap must be sorted into specific classes based on the requirements for the steel grades to be produced. It’s essential impurities are identified at this stage to avoid unwanted tramp elements ending up in the melt. As scrap comes in all shapes and sizes, the main analyzer requirements here are portability and speed.

For rapid alloy identification, handheld LIBS (laser induced breakdown spectroscopy) analysis is sufficient. However, measurement of low levels of sulfur or phosphorous requires XRF (X-ray fluorescence) or OES (optical emission spectroscopy) technology.

EAF ANALYSIS

Bath chemistry analysis is primarily used to detect phosphorous, sulfur, aluminum, silicon, manganese and carbon as solid impurities, and hydrogen and nitrogen as dissolved gasses. Slag analysis is important at this stage to ensure correct basitivity and to promote the production of foam slag.

Several measurements may be required to ensure impurities are at the right level. For EAF melt chemistry and slag analysis, OES technology is needed because of the low detection limits and element types. A dedicated analyzer for this task is recommended for rapid analysis and feedback on processes.

SECONDARY PROCESSING

Secondary processing in ladle furnaces may include de-slagging, alloying and vacuum degassing, and analysis is carried out after each of these steps.

Slag process control at this stage is to remove impurities that have not been removed in the EAF and XRF technology delivers the accuracy required.

Determining the exact alloy composition needs a technology that can detect a wide range of elements at very low levels and OES is the best technique. OES is also essential for vacuum degassing analysis, as it’s necessary to control hydrogen to ultra-low levels in certain types of steel.

CASTING

Continuous and ingot casting require careful monitoring of composition when mixing a new grade or batch. Today’s specifications are complex and stringent as products are used in high-stress environments, such as aerospace or marine applications.

OES is the only technology that can analyze the complete spectrum of elements down to the limits required.

FINAL SPECIFICATION

Most robust quality control programs will need a final compositional verification check. This is to create a final component composition certificate and to avoid the risk of material mix-up when preparing shipments.

The finished parts may be very large, and it may not be possible to take the parts to an analyzer. Instead, you can choose between mobile analysis or in-line automation. For many applications, a handheld XRF analyzer will be ideal. However, if you need to verify low alloy steels or light elements such as carbon, boron or other low-level elements, OES is the best technology to use.