Since 1949, when the first systematic study of the cost of corrosion, led by Herbert H. Uligh in the United States, was published, the huge amounts of money lost due to corrosion and spent on preventing and controlling it have been compared to one of the more relevant economic indices, such as the Gross Domestic Product (GDP). This is an index proposed more than three hundred years ago.
Two of the latest estimates of the cost of corrosion are from studies conducted in the United States in 2013 and in China in 2015. In the first case, the annual cost of corrosion was estimated at 3.4% of GDP; in China, it was estimated at 3.34% of GDP.
When looking for results in other latitudes, it is common to find that GDP percentages are usually lower. For instance, in Colombia, a study led by the author several decades ago found that the total cost of corrosion was about 2%.
A reason for this relevant difference could be related to the GDP index. It is a broad measure of a region's economic growth over a period, usually a year. However, corrosion seems to be more related to other issues.
Economists are seeking a new index of the current true wealth. Corrosion costs must be related to an index other than GDP.
Disparities in GDP differ from disparities in richness, development dynamics, and steel consumption.
We need a more realistic index, more directly associated with the magnitude of the corrosion phenomena, and steel consumption is a clear indicator of that magnitude.
Steel accounts for nearly 95 percent of total metals consumed worldwide. Worldwide, steel consumption averages about 4 tons per person; in developed countries, it is about 15 tons per person; and in Sub-Saharan Africa, it is less than 1 ton per person. More than 95 percent of corrosion costs are attributable to steel corrosion, but applying the same percentage across all countries is not appropriate.
This point of view is closely tied to an older consideration of the magnitude of corrosion problems and to the use of a system that accounts for a significant percentage of the steel produced in the replacement of corroded parts and structures.
Right now, it is more important to correlate the cost of corrosion with steel consumption across countries and regions. The table below presents results from studies on the cost of corrosion in Colombia (CO), the United States (US), and China (CN). It also shows the total apparent consumption of steel over the 50 years preceding the studies, or the metals that were truly exposed to corrosion associated with the found costs of corrosion. It calculates the cost of such quantities of steel at 2025 prices (US $465 per ton), the percentage of corrosion cost relative to steel cost, and, finally, the cost of corrosion in 2025, estimated for each country.
Table: Comparison of the Measured Cost of Corrosion with the Cost of the Exposed Steel
Apparent Steel Consumed (ASC) over the last 50 years before the study, and extrapolation to 2025.
| Country | Year | Original Corrosion Cost (US $B) | Projected Corrosion Cost 2025 (US $B)* | ASC (M ton) | Cost of the ASC 2025 (US $B) | Corrosion Cost (%) | Cost of Corrosion in 2025 (US $B) |
|---|---|---|---|---|---|---|---|
| CO | 1994 | 1.3 | 2.8 | 33.1 | 15.3 | 18.34 | 2.7 |
| US | 2013 | 451 | 619 | 4,850 | 2,255 | 27.45 | 441.8 |
| CN | 2015 | 310 | 418 | 10,150 | 4,719 | 8.86 | 484.7 |
* Historical corrosion costs have been adjusted to 2025 US dollars using the U.S. Bureau of Labor Statistics CPI-U, so they are directly comparable to the cost of the ASC at 2025 prices.
In conclusion, GDP is not a reliable indicator for estimating the cost of corrosion across all countries worldwide. The level of corrosive attack depends strongly on the nature of natural environments (continental, coastal, landlocked, tropical, etc.) as well as on anthropogenic ones (industrial, urban, domestic, etc.), and on the anti-corrosion forces (ACICOR, AMPP, CSCP, enterprises, universities, etc.). These environments are directly related to the degree and dynamics of development, which are associated with steel consumption and exposure conditions, and do not depend on total income measured by GDP.
In corrosion, we never generalize; we say that "each case is a case."
