Today's mailbag will just be answering one question that we here at ASMC receive multiple times for customers looking for stainless steel products.
Scott asks: Can you tell me the difference between the stainless steel grades? I'm not sure if I need 304, 316 or 410 for my application?
Thank you so much Scott. Before we break down the different grades of stainless steel fasteners, lets first understand the basics as to why someone would choose stainless steel finish over another type of material (i.e. zinc plated for example).
Stainless steels are known for their corrosion resistance. Their are numerous grades with varying chromium and molybdenum contents to suit the environment the alloy must endure. Stainless steel's resistance to corrosion and staining, low maintenance, and familiar luster make it an ideal material for many applications where both the strength of steel and corrosion resistance are required.
304 Stainless Steel- the most common stainless steel. Also called A2 stainless or 18-8. Higher corrosion resistance than regular steel. In terms of 18-8, the first number refers to the amount of chromium (i.e. 18%) and the second number refers to the amount of nickel (i.e. 8%). When there is no nickel the stainless grade family is the "400 series".
316 Stainless Steel- Also called A4 stainless. Similar to A2 except 316 contains 16% chromium, 10% nickel and 2% molybdenum which results in increased corrosion resistance.
Note: With all 300 series stainless steels containing nickel, they are non-magnetic. They are also not able to be heat treated. If there is an "L" after the grade, it indicates a lower carbon content and is usually used when welding is being performed.
410 Stainless Steel- contains chromium and no nickel. Magnetic. 400 series stainless steel is generally used for applications which involve mild corrosion, high strength, and heat resistance. Resistant to atmospheric conditions, water and some chemicals.