In the steelmaking process, there are several impurities that can be detrimental to the quality of the steel produced. Steelmakers strive to make these impurities conform to the wanted purity / impurity ratio acceptable for the end product to function as needed by the manufacturer. These impurities include, Alumina, Silicon, Sulphur, Phosphorous, Lead, Tin, Manganese, Oxygen, Nitrogen and Hydrogen.
Some of these impurities are more detrimental than others, but all must be carefully monitored. Too much or too little of these materials can cause the steel to form incorrectly, ending up brittle and unusable. Sulphur, for example, is very harmful, causing the steel’s strength to be reduced. Often times, manganese is added to counter the sulphur, causing it to form manganese sulphide (MnS) instead of iron sulphide, increasing the strength and tenacity of the steel produced. In addition, MnS improve machineability of steel as well.
Another side effect of metal impurities is they can affect the grain size of the steel. While phosphorous can increase the strength of steel, it also increases the grain size and decreases the ductility. By refining the grain of the steel, the manufacturer can increase the strength and reduce the ductile-brittle transition temperature of the metal.
In order to maintain the standards for the type of steel being created, manufacturers must closely monitor the amounts of metal impurities added into or created by the steelmaking process. Modern equipment plays a large role in the manufacturing of steel, from new steel furnaces to top-of-the-line inclusion analysis software. Having an analytical tool within the steel line can vastly improve the quality of the steel produced.
The Aspex Personal SEM equipped with the Metal Quality Analyzer (MQA) software takes the guesswork out of the steelmaking process. The MQA provides up-to-date inclusion compositional information, allowing adjustments to be made quickly to counter negative impurities. Since the PSEM is a fully-integrated SEM/EDX machine, the system is able to quickly and accurately report count, size, and elemental composition of the sample scanned.
Implementing the Aspex MQA provides benefits to the manufacturer that can vastly outweigh the upfront cost. From comparing inclusion counts to standards and analyzing steel cleanliness vs. time, to alloy development and consumable consumption reduction, the Aspex PSEM with MQA software in an all-in-one analytical system designed with the metal industry in mind.
Reference:
Aspex
http://aspexcorp.com/industries/metals.html
Chest of Books, “An Elementary Outline Of Mechanical Processes,”
http://chestofbooks.com/crafts/mechanics/Mechanical-Processes/index.html
Office of Scientific and Technical Information
http://www.osti.gov/bridge/servlets/purl/861397-Tb7pb9/861397.pdf
Codecogs Engineering
http://www.codecogs.com/reference/engineering/metallurgy/impurities_in_steel.php
