CORROSION OF STAINLESS STEEL PRODUCTS

Stainless steel is an alloy of iron containing at least 10.5% chromium. This chromium allows the formation of a very thin oxide layer on the metal surface, also known as the “passive layer” and gives stainless steel its distinctive shine.
Passive coatings like this help prevent corrosion of metal surfaces and thus improve corrosion resistance by increasing the amount of chromium in the stainless steel. By combining elements such as nickel and molybdenum, various stainless steel alloys can be developed, giving the metal more useful properties, such as improved formability and higher corrosion resistance.
Stainless steel products produced by steel pipe manufacturers will not corrode in “natural” conditions or aquatic environments, therefore, cutlery, sinks, countertops, and pans made of steel Household stainless steel is commonly used. However, it is important to note that this material is “rustless” and not “stainless” and therefore in some cases corrosion will occur.

What can cause stainless steel to corrode?
Corrosion, in its simplest description, is a chemical reaction that affects the integrity of metals. If metal comes into contact with an electrolyte, such as water, oxygen, dirt, or another metal, this type of chemical reaction can be created.
Metals lose electrons after a chemical reaction and thus become weaker. It is then susceptible to other future chemical reactions, which can create phenomena such as corrosion, cracks, and holes in the material until the metal weakens.
Corrosion can also be self-perpetuating, meaning that once it starts it can be difficult to stop. This can cause the metal to become brittle when corrosion reaches a certain stage and it can collapse.

DIFFERENT FORMS OF CORROSION IN STAINLESS STEEL
Uniform Corrosion
The most common type of corrosion that can affect stainless steel and other metals is called uniform corrosion. This is the “uniform” spread of corrosion across the surface of the material.
Interestingly, it is also known to be one of the more “benign” forms of corrosion, although it can cover relatively large areas of metal surfaces. Indeed, its impact on the material’s performance is measurable as it can be easily verified.

Pitting Corrosion
Pitting corrosion can be difficult to predict, recognize, and differentiate, meaning it is often considered one of the most dangerous forms of corrosion.
This is a highly localized type of corrosion in which a small area of ​​pitting corrosion is formed by a localized anodic or cathodic spot. Once this hole is firmly established, it can “build” on itself so that a small hole can easily form a cavity that can be of many different shapes and sizes. Pitting corrosion often “migrates” downward and can be particularly dangerous because if left unchecked, even if a relatively small area is affected, it can lead to structural failure of the metal.

Crevice Corrosion
Crevice corrosion is a type of localized corrosion that results from a microscopic environment in which two metal regions have different ion concentrations.
In places such as washers, bolts, and joints that have little traffic allowing acidic agents to penetrate, this form of corrosion will occur. The reduced amount of oxygen is due to a lack of circulation, so the passive process does not occur. The pH balance of the aperture is then affected and causes an imbalance between this area and the outer surface. In fact, this causes higher corrosion rates and can be exacerbated by low temperatures. Using proper joint design to reduce the risk of corrosion cracking is one way to prevent this form of corrosion.

Electrochemical Corrosion
If immersed in a corrosive or conductive solution, two electrochemically different metals come into contact, forming a flow of electrons between them. Because the metal with less durability is the anode, the metal with less corrosion resistance is often more affected. This form of corrosion is called galvanic corrosion or bimetallic corrosion.