Carbon steel (CS) or Stainless steel (SS)?

In less than two weeks from now, there will be another occasion for Corrosion Awareness Day: it is the time when corrosion professionals speak about important topics in corrosion for other corrosion professionals as if all-year-round occasions organised by #AMPP, #ACA and #EFC is not enough for presenting such highly technical topics. Again, during this year’s “Awareness” day, instead of seeing economists, ecologists and those who can change the research and development paradigm in corrosion science and engineering, we will face with successfully carried out PhD or Postdoctoral (so-called early stage researchers) projects. The same theme every year and counting….

However, instead of repeating my point that Corrosion Awareness Days now have become a “missing target”, I ‘d like to focus on a question that may sound too obvious to a “traditional corrosion professional”: do you prefer CS or SS?

A traditional corrosion professional who confines him/herself to knowing techniques, reading standards, recommended practices and manuals due to the nature of his/her job will definitely choose SS. His /her reasoning is simple: SS shows anti-corrosion properties superior to CS. Also, for specific conditions standards and recommended practices all direct to using SS.

However, there are other sides to this that a smart corrosion professional whose knowledge exceeds corrosion handbooks and manuals would think about. These are:

1. None of the top global vendors and manufacturers of stainless steel are in The Middle East (GCC), CIS or Africa ( https://blog.technavio.org/blog/top-11-vendors-global-stainless-steel-market). What does it mean? It means that when a corrosion professional in Suadi Arabia, Iraq, Iran, Oman, Turkey, Baku, Turkmenistan, Venezuela, Libya, Egypt,…. orders use of stainless steel, unconsciously, he/she is helping his/her country’s currency to be transferred outside and to the pocket of the eleven giants we just mentioned. ?
2. There is a very important concept that is not that well known by corrosion professionals, and it is the concept of Embodies Energy (EmE). Embodied Energy can be defined as the energy consumed by all of the processes associated with the production of a structure from the acquisition of natural resources to product delivery. EmE is mainly used by Civil Engineers but it must be of vital importance to Materials and Corrosion professionals too: The importance of EmE is its relationship with the release of one of the most important Greenhouse gases, i.e., carbon dioxide: it has been quoted that every Giga Joule (Gj)of energy produced results in the release of approximately 0.098 tonnes of carbon dioxide into the atmosphere, therefore making EmE “ a measures to assess the environmental impact of .. Materials and processes”. (R. Javaherdashti, "A Global warning on corrosions and Environment: A new look at existing technical and managerial strategies and tactics", VDM Germany 2010.)

How is EmE related to our discussion for material selection between CS and SS?

EmE for stainless steel is 56.7 MJ/kg whereas for carbon steel the EmE is 13.1 MJ/kg for Engineering Steel (Craig I. Jones, Geoffrey Hammond “Embodied energy and carbon in construction materials”, Article in Proceedings of the ICE - Energy · January 2008, DOI: 10.1680/ener.2008.161.2.87) and 38.8 MJ/Kg (https://www.yourhome.gov.au/materials/embodied-energy).This would mean that the carbon dioxide produced by SS will be between 1.5 to six times more than that produced by CS. In other words, SS contributes to generating more Greenhouse effect than CS.

I would suggest that if you are from those geographical regions I mentioned and work as a corrosion professional and that you have to do a materials selection, use CS but put much more emphasis on corrosion monitoring and overall corrosion management instead. You may have shorter service life in your assets; however, you can be sure that you have avoided the above-mentioned important disadvantages. ?

Therefore, when recommending to use SS, unless it is urgently necessary, think twice!