Home » What is the difference between 304 and 316 stainless steel?
Stainless steel is the term applied to identify the steel families that contain at least 11% of chromium, which is the chemical element that affords the material a high resistance to corrosion.
Other elements such as nickel, molybdenum and titanium, for example, allow the stainless steel to be bent, welded, deep-drawn and worked on in such a way to be applied to various different products. The selection of the correct stainless steel grade and relevant surface finish is very important to afford the material a long life. The main stainless steel families are: Austenitic – Ferritic – Martensitic.
The steel used by Mondeo to manufacture its products belongs to the austenitic family (Series 300).
According to application, our products are available in stainless steel 304 or stainless steel 316.
How can we tell a 304 from a 316 grade material?
The fundamental difference between these two steel grades is that 316 grade has molybdenum and 304 doesn’t. There are several products available in the market that are used for a quick detection of molybdenum content. A small area of the material is previously submitted to a quick sanding. Afterwards, 2 or 3 drops of reagent is added to the relevant surface. The drops are stirred with a plastic rod. After a few minutes the reagent changes color from yellow to brown if the material has molybdenum content. If it stays yellow, the material is not a 316 grader. It is important to know that those tests are not quantitative. The reagent also produces a brown color with molybdenum contents lower than 2%, which is the minimum content acceptable to consider a material a 316 grader.
Is 316 grade always more resistant to corrosion than 304?
No. In many cases, the 316 grade has higher resistance to corrosion. However in the presence of nitric acid and some more oxidizing media, the 304 grade responds better than 316.