Stainless steel is also a type of metal. Let’s first talk about why metal rusts. There are three most commonly used metals in our daily life, namely copper, iron and aluminum. Let’s talk about iron first. Iron is a very active metal. Iron can react directly with oxygen in the air. Their product is what we usually call rust. Copper is relatively inactive, but copper can also react with oxygen and water to form patina, while aluminum is more reactive and can directly form an oxide film at room temperature. The reason why people still widely use aluminum is because the oxide film is dense and can prevent The air continues to react with the aluminum inside, playing a protective role. Therefore, the role of stainless steel is generally to replace that particularly reactive metal and extend the service life of the material.
Stainless steel, just because it is stainless steel, does not mean that it has no chemical properties. After all, stainless steel is also an alloy. As long as it is an alloy, it has the properties of metal. It's not that stainless steel doesn't undergo chemical changes, it's just that the changes are slower. Therefore, it is very normal for stainless steel to rust. I'm not surprised anymore. It's just that the name is misleading: stainless steel does not rust. You must know that nothing in this world is absolute, and the same is true for metal.
In fact, metal rust also has a lot to do with the environment. Most chemical reactions rely on conditions to support it. You said that if you put copper in dry air, it will not rust, because there is no water. If you put iron in the air, regardless of whether it is dry or not, it will rust, but it will rust when it is dry. Slowly, it rusts faster when there is water. The environment is also an important factor affecting the rust of stainless steel. No matter how good the stainless steel is, it will not work if it is left in water for a long time, let alone the positive and negative poles of the power supply. As long as electrons are gained and lost, it doesn’t matter what conditions you have, as long as the electrons are transferred , then a chemical change occurs. Will stainless steel rust?
So stainless steel also needs to be protected. Try not to place stainless steel in humid places, and do not place stainless steel at the poles of the power supply. As long as your protection measures are in place, stainless steel is basically really stainless. .