Stainless Steel Electrical Enclosure Grades – 304 or 316?
Date Posted:16 May 2017
The two most common stainless steel grades used in the manufacture of electrical enclosures are 304 and 316. More and more, consultants and clients are asking for 316 grade stainless steel. What is this and why does it matter?
You may think that, true to their name, stainless steels don’t rust or tarnish. Unfortunately it isn’t that simple. All steels have the same elementary content of carbon and iron. Stainless steels also contain chromium (minimum 10.5%), an element well known for its resistance to corrosion.
However, after that it gets complicated. There are multiple grades of stainless steel, each with slightly different compositions of alloy ingredients, causing different physical characteristics.
As stated, the two most common stainless steels are 304 and 316 grade. 304 grade is slightly cheaper. 316 grade is essentially the same elementary makeup, with the crucial exception that it contains molybdenum, typically around 2-3%. When molybdenum is added to stainless steel it increases the pitting resistance measure (known as PREN) by 3.3%. Put simply, this means the corrosion resistance of 316 grade stainless steel is 3.3% higher than 304 grade.
Practically this means grade 316 has significantly superior corrosion resistance in a wide range of applications, including chemical plants, marine environments and architectural installations. It is resistant to most food processing environments, can be readily cleaned, and resists organic chemicals, dye stuffs and a wide variety of inorganic chemicals.
Grade 316 should not be used where exposure to strong reducing acids is possible, or in environments with temperatures above 50-60°C and with chlorides present. In these situations enclosures made from GRP are recommended.