Iron Inclusion Impurities Analysis With SEM

Impurities in iron cause defects and flaws within the material that, when creating steel, leads to a poor quality product. Several impurities that can be found in iron, or pig-iron, include silicon, phosphorus, manganese, sulphur, copper, tin, tungsten, antimony, and titanium. Each of these has a different effect on the iron; steel created with phosphorus-laden iron makes it brittle, while using iron with a lot of manganese in it for steel creation counteracts the red shortness.

Once pig iron is smelted, there are three options how to proceed to have a valuable product: creating wrought iron, cast iron, or steel. The further reformation needed to transform pig iron into steel involves keeping close watch on which steel inclusions make it into the final mix. The impurities found in iron have similar effects on steel, causing brittleness, ductility lose, red-shortness, and strength reductions. Steelmakers, thus, must monitor the steel in each step, assuring that the additives are beneficial and the impurities are pulled out.

Monitoring particles on the micron-level during the steelmaking process presented a challenge to analytical tools available. Manufacturers demanded that the analyzer be able to perform under adverse conditions, and still offer quick, accurate analytical results. In response to these demands, Aspex created the Metal Quality Analyzer (MQA) for its Personal Scanning Electron Microscope (PSEM).

The PSEM with the MQA software is a fully integrated SEM/EDX machine, and is capable of sizing, counting, determining elemental composition, and automatically creating a report directly in the steel line.   Once the impurities are identified, manufacturers can take corrective action to remove the foreign particles before they make it to the final product.

The steelmaking process is one of checks and balances. Too much of a good additive might end up becoming a detriment itself. Too little, and the carbon content might be too great for the quality of the end product. Manufacturers must maintain a closely monitored system to produce high-end steel. The PSEM with MQA software from Aspex allows them to do so right in the product line. The MQA can scan and characterize upwards of 10,000 inclusions per hour, making it the fastest on the market and can save manufacturers energy and costly re-melts.

Reference:
Aspex, http://www.aspexcorp.com/industries/metals.html

Chest of Books, http://chestofbooks.com/crafts/metal/Applied-Science-Metal-Workers/467-Influence-Of-Impurities-On-Steel.html; http://chestofbooks.com/architecture/Building-Construction-2/Impurities-In-Pig-Iron.html

How Stuff Works, http://science.howstuffworks.com/iron.htm/printable