Development and analysis of fire suppresion during steel quenching : Three paths of analysis of fire- and smoke suppresion during steel hardening processes

Abstract: This thesis looks at an issue of excessive fire and smoke development during open tank quenching. The quenching in question being done as part of a hardening process of steel springs during manufacturing at Lesjöfors Fjädrar AB. The thesis was written under supervision of of Rejlers Sweden AB. The problem which sought to be solved was stated as what can be done to minimize the amount of fire and smoke developed and what can be done to minimize the risk posed by the fire and smoke?  Three distinct possible solutions were found that themselves could be categorized as either a preventative solution or a mitigation solution.  Two preventative solutions were considered, these being optimization of the current process and substitution of the oil. The optimization sought to understand if the fire and smoke could be minimized through changing the current maintenance processes of the oil through quality measurements of the oil in use. The substitution solution considered the feasibility of substituting the hardening oil with a polymer hardening, with the benefit of the polymer medium being inflammable and non-smoking. The mitigation solution was developed through the means of product development as a physical shield which would encapsule the open tank during quenching and protect the surrounding area from the fire and smoke developed. The optimization analysis measured key attributes of the oil to be of good quality and not a contributing factor of the issue. The substitution and mitigation solution were both presented to Lesjöfors as possible solutions to their problem, and they found the mitigation solution to be the most viable for their specific needs. While these solutions was developed with a specific situation as their foundation are these methods of reaching these solutions applicable other open tank quenching situations.