304 Stainless Steel Alloy

From its use in kitchen appliances, to various levels of industry, one of the most widely used varieties of stainless steel is grade 304. The primary reasons why you can find this grade almost everywhere is the flexibility it gives to those working on it, and the high level of corrosion resistance, which is a must for any metal that regularly comes in contact with water or salt. These two factors combined allow manufacturers to mold the steel in almost any shape, and allows the consumer to use it in any everyday application.

The first thing you need to know about Grade 304 stainless steel is that it contains both Chromium and Nickel. In fact, you will see that common grades of stainless steel are marked as 18/8 or 18/10, which refers to the percentage of Chromium and Nickel found within the compound respectively. Typically, 304 stainless steel has between 16 and 24% Chromium content and could contain somewhere between 0 and 35% Nickel.

Grade 304 stainless steel is referred to as austenitic, which means that the Nickel level within the steel itself adds a level of corrosion resistance. Also, austenitic steel is not heat treatable and is not magnetic. Furthermore, as compared to other Carbon Steels, stainless steel 304 is far less conductive of electricity and hot and cold temperatures. When the Nickel levels are low, the steel is referred to as ferritic instead of austenitic, however most of the stainless steel with a grade in the 300s is austenitic by nature.

Grade 304 stainless steel also shows a high level of workability for the manufacturers. It exhibits a low yield strength, combined with excellent drawdown properties and the ability to be elongated to serve various needs. You can form stainless steel 304 in a variety of shapes and sizes, including ones that are more complex than what other metals can handle. This is why it is considered to be the most versatile stainless steel on the market, which also makes it the most abundant.

You might be wondering, what exactly makes Grade 304 stainless steel that resistant to corrosion to begin with. That property lies in its chemical composition. Rust is made up of a compound known as Iron Oxide. Therefore, it is reasonable to assume that anything that has high levels of iron is going to rust, because oxygen occurs naturally all over the world, including water. Once Iron has started to rust over, its structural integrity begins to wane, allowing it to crumble easily to the touch. Needless to say, it is not very reliable in very many situations. Once this rust crumbles off, the Iron underneath becomes exposed, and begins to rust as well. After a while, your entire iron piece as become useless.

So what sets stainless steel apart? It is because of the Chromium found within the compound as opposed to Iron. When Chromium reacts with the oxygen inside water, it becomes Chromium Oxide. While Chromium Oxide can become discolored like its Iron Oxide equivalent, the Oxygen does not spread to other layers quickly, because of the density of the compound itself. If the Oxygen is not allowed to spread quickly, then neither does the rust. Chromium Oxide is also self-renewing, which means that the layers themselves can begin to replenish. What this means overall is that 304 stainless steel ruts at a much slower rate than Iron, which means it keeps its structural integrity for far longer.

Aside from the Chromium and Iron, there are a variety of other elements that make up 304 stainless steel. You can find trace amounts of Manganese, Nitrogen, Silicon, Sulfur, and Phosphorus inside the steel. Also, just like most everything in the world, there is Carbon present, however it is much lower than what is found inside other metallic alloys. There is also Iron inside Grade 304 stainless steel, but not enough that is going to make it rust quickly like other metals.

Grade 304 stainless steel can be broken down into two subcategories known as 304H and 304L. Items that are made using the 304L variant tend to be a heavier gauge, which allows them to be welded easily. However, once the steel has been welded, it is possible that it might need solution annealing so it can maintain its excellent level of corrosion resistance. It also has less Carbon then its 304H equivalent.

When you are working with the 304H variant, you will see that it is much more suitable for environments where high temperatures are present. In fact, 304H can withstand temperatures up to 1500 degrees F before it begins to scale. However, when it is used in temps below 900 degrees F, the corrosion resistance also begins to deteriorate.

Grade 304 stainless steel can be found in strip, bar, sheet, or tube forms and can be found in either industrial or household items. Things like screws, kitchen utensils, and machinery parts commonly are made of stainless steel 304. You can also find it in parts used to make vaporizers as the high level of water used in the product can make it rust quickly unless it is made of the right material.

For more information on 304 stainless steel properties, contact ESM Hampshire Mill at 847-683-0500.