Is 316L more expensive than 316?
What is 316 and 316l stainless steel?
Stainless steel comes in several grades and is divided into four major categories. One of the most important categories is austenitic stainless steel. Austenitic stainless steel alloys are further divided into several categories based on their chemical composition. One of the most prominent stainless steel grades belongs to the 300 series. These grades are widely used and their uses cover several sectors including shipping, offshore engineering, general engineering, petrochemical industry as well as pharmaceutical and food industries. Having said that, grade 316 is the second most used alloy in the 300 series. Like most austenitic stainless steel alloys, grade 316 is modifiable. Modifications to stainless steel tend to be based on its application.
Typically, modifications are minor additions or subtractions of elements for a specific chemical composition. For example, marine grade 316 stainless steel has a higher carbon content in the alloy. Carbon forms carbide precipitates at high temperatures and causes sensitization at the grain boundary precipitates. Due to sensitization, the metal becomes weaker during welding operations. Welding temperatures are usually higher because the metal needs to be melted in order to fuse it to another part or fuse itself to form a complete component. Therefore, the corrosion resistance of the melted portion (i.e., the weld zone affected by the heat) tends to be weaker compared to the rest of the surface of the component. Since the other surface areas are not heated by the welding process, the corrosion resistance remains stable. This is a problem that affects 316 grade stainless steel welded parts. To solve this problem, manufacturers designed a low carbon version of this particular alloy.
Price Difference Between 316 and 316l Stainless Steel
While there are elemental variations in the alloy, the material can be dual certified because the variations tend to be at very small levels. Therefore, dual certified alloys will be labeled as 316/316L. Therefore, the prices of these two alloys are almost the same.
316 vs 316l Comparison
In addition to the lower carbon content in 316L grade stainless steel, manufacturers also add nitrogen to their alloy. There are several reasons for adding nitrogen to the alloy. First, as the carbon is reduced, the overall mechanical strength of 316 grade stainless steel decreases. Second, its heat resistance also decreases. However, it is due to the lower carbon content in its chemical composition that the 316L grade stainless steel has the potential to be welded without being affected by intergranular corrosion.
Differences Between 316 and 316l Corrosion Resistance
As mentioned earlier, the 316 grade stainless steel was introduced to the market with the intention of achieving its excellent weldability. The reduced carbon content effectively reduces the alloy's vulnerability to intergranular corrosion, especially to the heat affected weld zone. Similar to the 316 grade, the low carbon version of this alloy can also be called marine grade steel as it can resist seawater and saline solutions. Therefore, this alloy is also dual certified to meet the needs of a wide range of applications. Additionally, like the 316 grade, it offers resistance to atmospheric corrosion or also known as oxidation resistance. Dual certified alloys are also useful in applications containing halogen compounds, including chlorine, fluorine, and bromine. Due to their corrosion resistance, they have become an integral part of the consumer goods industry.
