- Materials & Industrial Technology
Some of the Worst Cases of Corrosion
As you probably know, metal has a tendency to rust. Tools and appliances, among other machinery, can easily corrode when they’re regularly in contact with humid conditions, which is why people should really take measures to make sure that rust doesn’t build up. I’ve found that electropolishing is a great solution to prevent water corrosion on my home appliances and tools, while also making cleaning a less grueling process for many metals. It’s easier than trying a more old fashioned method of metal polishing, though it can be done.
You might be curious to know what electropolishing is, first. Well, this process is done by using an electrochemical bath to cover any metal. Once the metal is dipped in the electrolyte bath, it is then electrically charged with a strong direct current. The metal begins to develop a passive (corrosion-resistant) coat that will keep the metal safe from rust, and it also produces a much shinier, stainless surface that’s easy to clean. Industries like food and beverage, airplane manufacturing and many others rely on this polishing method to make their tools or machinery last longer.
One of the common misconceptions about rust is that it is only skin-deep on metals, when in reality if there’s rust on top then there’s most likely more lying beneath, deteriorating the metal. This can be extremely dangerous if a crucial part of a machine is made of thinner metal that can corrode more quickly, causing it to break. Here are some of the more famous disasters caused by corrosion, which could have been prevented using thorough electrochemical polishing.
Guadalajara Sewer Explosion
In 1992, nine separate gasoline explosions in a sewer caused major damage to 1,600 buildings and injury to 1,500 people. The explosions in Guadalajara’s district of Analco created a two-kilometer-long trench, with holes that were up to fifty meters across and six meters deep. Miles of roadways were destroyed, as one witness even claimed that a bus was swallowed up by one hole.
One of the causes of the explosions was the corrosion of a galvanized steel pipeline and a gasoline pipeline that both endured a humid environment. Eventually, the corrosion got so bad that gasoline leaked from the gas pipe into the main sewer line. The next factor in the explosions came about when the siphon in the sewer failed to siphon the fumes over an underground railway. Even the strong smell of gasoline noticed and complained about by locals went ignored by the authorities.
The preventable pipeline explosions caused $75 million in damages, and killed 215 people.
Boeing 747 Freighter Crash
Yet another disaster that occurred in 1992, this corrosion-instigated accident involved an EL AL 747 freighter that crashed in Amsterdam. The accident unfortunately resulted in the loss of the four people on board, as well as over 50 civilians on the ground. The reason for the crash was that the connection between the engines and the wings corroded, which caused two engines to detach and make the plane uncontrollable.
The accident was caused primarily by a combination of corrosion and fatigue, specifically on the fuse pins that attach the strut to the wings. Corroding pits, most likely resulting from a lack of passivity, eventually caused the pins to weaken and fall apart. Following this crash, Boeing set about upgrading the design of the 747, implementing corrosion-prevention techniques in the fabrication of parts. Most aircraft part manufacturers today use electropolishing or other preventative methods to keep parts from deteriorating.
Oil Spill Caused by the Corroding Tanker Erika
This accident took place in 1999, and involved the Maltese tanker Erika, which broke apart and subsequently sank about 70 kilometers off the coast of Brittany, France. The ship carried around 30,000 tons of oil, and nearly two-thirds of it spilled into the ocean when Erika sank.
Needless to say, it was one of the worst shipping accidents in history. The nearby region of France took the brunt of the economic fallout, with plummeted tourism income, lost income from fishing and the inability to trade any sea life products such as crabs. Of course the environment suffered tremendously, as this accident spilled more oil than what was spilled worldwide in 1998.
The worst thing about this accident is that—like just about every other case of corrosion—it could have been prevented. Inspections beginning in the early 90’s determined that corrosion was going on, with watertight doors that wouldn’t seal properly along with rusted holes and other noticeable faults. They kept the tanker running, though, until it finally had it and broke in two during severe wind.
An application that improved the passivity of the ship could have let it hold out much longer, but because of the ignorance regarding maintenance, it became responsible for one of the worst environmental disasters. And although none of the crew members died, the marine life nearby suffered the biggest losses.
Electropolishing is a Savior
All of these accidents could have been perfectly avoided if there were proper maintenance measures. If it wasn’t for electropolishing, not only would more unexpected accidents and general damage to tools and machines happen, but we’d be spending a lot more on them. Today, it’s one of the best methods to use when looking to strengthen just about any metal imaginable, in any industry.