Certain concentrations of sulfuric acid in steel can cause corrosion.
Sulfuric acid is a strong acid capable of responding in many different ways, and the reaction of sulfuric acid in steel can sometimes be contradictory. At certain concentrations, sulfuric acid will form a protective layer on the steel and the steel will be fine. Other concentrations will produce corrosion and the steel will slowly deteriorate. As steel corrodes, sulfuric acid often forms hydrogen gas, which favors corrosion. Low levels of hydrogen gas can cause steel to warp or warp.
The best reaction of sulfuric acid in steel is that the acid starts to create an iron sulfate layer which protects the steel from the acid and causes no corrosion and little metal loss. This will only happen if the sulfuric acid concentration is between 70% and 99.5%. At a concentration in this range, it can be stored in an unprotected, unlined steel box.
As with most substances, the most common reaction of sulfuric acid in steel is corrosion. Regardless of whether the concentration is below or above the safe concentration range, sulfuric acid will begin to corrode the steel. Corrosion is usually slow, but very high concentrations can quickly corrode steel. To keep sulfuric acid at safer concentrations, a steel box lined with iron sulfate should be used, and the liner should be replenished as needed, if possible.
When sulfuric acid in steel reacts, there is more than metal loss taking place. A by-product of this corrosion is hydrogen gas, which works by removing the protective layer of iron sulfate. This is because the hydrogen in sulfuric acid is released to make way for iron in the steel, which causes the hydrogen to turn into gas. This causes the steel to corrode to accelerate and, if not corrected, will make corrosion inevitable. For this reason, the steel case must be checked and the protective layer replenished frequently.
A low level of hydrogen gas may not doom the metal to full deterioration, but may instead cause changes in the steel’s shape. If the hydrogen gas is light, then the moment you remove any of the iron sulfate, the reaction between the sulfuric acid and the steel will automatically produce more iron sulfate. This constant rise and fall of corrosion, shielding and hydrogen gas means that the steel will normally notch or warp in random directions. At this point, the steel is often unusable, especially if it functions as a pump to move sulfuric acid.