The quality of steel produced relies on a combination of several factors. Most notable are the quantity of carbon incorporated into the mixture and the types of impurities present. By understanding what impurities are present and what qualities they provide, steelmakers can improve the quality of steel produced.
Other than carbon, there are several other impurities generally found in steel. These include, but are not limited to, alumina, silicon, sulphur, phosphorous, lead, tin, manganese, oxygen, nitrogen and hydrogen. While some compounds are added purposefully, such as calcium carbonate to aid in the removal of sulphur, others are present from the iron ore itself and need removed.
Types of inclusions found in steel are various oxides, including calcium oxide, and phosphates, such as iron phosphide, and sulphides, iron sulphide or manganese sulphide mainly. Since sulphur is harmful if left to combine into iron sulphide, these inclusions must be carefully monitored and corrective action must be taken; otherwise, the steel will be too brittle to use. Likewise, excess inclusions of any type can have a detrimental effect on the quality of steel produced. Too much sulphur makes the steel brittle, while too much phosphorous reduces the ductility and increases the grain size. Both these, as well as other possible inclusions, must be closely monitored and identified to create a quality product.
In order to identify and assess the number and types of inclusions, Aspex has created a fully-integrated software platform for its Personal Scanning Electron Microscope (PSEM). The Metal Quality Analyzer (MQA), like its name suggests, quickly identifies, sizes, and provides elemental composition information for the manufacturer, analyzing the quality of the sample and identifying trouble spots.
The MQA is an automated analysis that uses the electron beam to scan a steel sample for inclusions. The ASPEX PSEM is integrated with an Energy Dispersive X-ray (EDX) which is used to determine the inclusion type and elemental composition. This allows for the MQA to quickly measure size, shape, determine chemical composition and have a customized report once analysis is complete.
The MQA can be placed directly into the product line, allowing the manufacturer to scan at any point needed to monitor the particles present. The Aspex PSEM with MQA software is capable of saving manufacturers significantly more than the upfront cost of implementation, and leads to a high quality product manufacturers can be proud to produce.
