Differences between 316L Stainless Steel and 304L

If you’ve ever wondered about the differences between grades of stainless steel, then this article is for you.  Two of the most common, 304L and 316L stainless steel, have one fundamental and prominent difference; the chemical composition. However, the composition then further separates the two in strengths and weaknesses, depending on the intended application. In this article, we’ll take a look at both the differences in makeup as well as usage between these two types of steel.

The composition

First, let’s begin by clarifying what the “L” means.  Simply stated, “L” refers to specific stainless steel that has lower carbon content.  Lower carbon is better for welding. Below is an overview of the chemical makeup of 316L and 304L stainless steel:

316L

•      16% chromium
•      10% nickel
•      2% molybdenum

304L

•      18% chromium
•      8% nickel

The differences in the properties

• Because of the presence of molybdenum, type 316L steel provides superior resistance to corrosion as compared to type 304L, especially in briny, salty seawater.
• Type 316L is resistant to sulfuric acid only when it is at low concentration, whereas type 304L is resistant to sulfuric acid even when it is in high concentration.
• Type 316L shows better resistance to phosphoric acid as compared to type 304L stainless steel.
• Grade 304L stainless steel has greater capability than grade 316L to break down and absorb energy without disintegrating.
• Tensile strength and yield strength of type 304L stainless steel bars are more than that of type 316L in their annealed condition.
• Type 316L shows better resistance to corrosion caused by de-icing salts as compared to type 304L steel. 

The differences in the usage

The applications of these two types of stainless steel differ based on their physical and chemical properties. Because of their somewhat malleable nature, grade 304L stainless steel bars are often used in the manufacturing of dippers, pipeline buckets, chemical storing tanks, and dye storing tanks.

Whereas the corrosion-resistant nature of type 316L stainless steel bar makes it ideal for marine vessel and related gear (except fasteners).

When deciding which metal is best for your application, it’s essential to evaluate all of the properties it provides.  316L stainless steel is durable, easy to fabricate, weld, and finish.  Furthermore, if budget is a concern, 316L provides a bit higher upfront cost but pays itself back in the long run.

For more information on stainless steel types, contact our team at Alliant Metals today (603) 329-4488.