When it comes to marine applications, fabricators often choose 316 stainless steel, as it’s highly corrosion resistant. 316 is available in different variants, such as L, F, N, and H. The L series is known for featuring lower carbon than 316—the concentration of the rest of its alloying elements remains unchanged. This offers 316L stainless steel natural immunity against weld decay, unlike 316, which requires annealing to achieve the same. Moreover, it has improved corrosion resistance to chlorides compared to type 304/304L stainless steel.
Below, we dive deeper into the unique applications of 316L stainless steel as well as some of the most common challenges fabricators face when machining 316L stainless steel.
Unique Application Areas of 316L Stainless Steel
316L stainless steel is the same molybdenum-containing austenitic steel as 316 stainless steel. Molybdenum offers immunity against crevice and pitting corrosion when the application involves exposure to chlorides or other halides. 316L is extensively used in process industries involving excess sulfur, such as paper and pulp factories. However, the molybdenum doesn’t prove to be helpful in highly oxidizing acids such as nitric acid.
Below are some unique application areas of 316L stainless steel.
Medical Implants
316 and 316L stainless steels are the most commonly used metals in body piercing jewelry and medical implants. 316L complements the ASTM F138 material standard for Surgical Implants (UNS S31673). As an ideal material, it is cheap, non-toxic, durable, and non-corrosive. A corroded foreign piece inside the body may lead to infection in the bloodstream, even possibly death. In this regard, 316L is highly corrosion resistant when in contact with biological fluid in cold-worked conditions. The presence of molybdenum offers a protective shield to the implant against a biologically-created acidic environment.
Heavy Welding Applications
In general, stainless steel is susceptible to intergranular corrosion due to the precipitation of chromium carbides between the grains during welding. It can also occur when carbon diffuses into the body of stainless steel from oil, plastic tape, and other organic substances under heat. The process is known as carburization. However, due to low carbon content, 316L thrives under such environments by offering excellent resistance to intergranular corrosion. Therefore, fabricators choose 316L over 316 in heavy gauge (>6mm) welded components.
Fancy Jewelry
When it comes to jewelry, 316L is the preferred stainless steel grade because it imparts luster to the piece and retains it over a longer period of time. The shiny appearance comes from extra molybdenum content, while superior corrosion resistance adds to its long life. 316L jewelry can be worn for a lifetime, as the colors won’t fade and react with your body in the absence of lead and nickel.
High-Spec Manufacturing
The 316L stainless steel alloy has always been in use for special manufacturing cases. For instance, 316L is the core material for manufacturing step voltage regulators designed to address unstable power supply in industries. The low-carbon steel adds longevity to the machine and reduces the cost of maintenance in the long run.
Large office buildings have curved sail-like structures of 316L with a special matte laminate finish. The purpose is to avoid reflections and to retain a smooth texture that should not change radically with time.
Industrial water filter housings use 316L electropolished stainless steel for the head and sump to avoid corrosion on chlorinated (municipal) and non-chlorinated (well water) systems and in several different applications.
There are also many other unique applications, such as in beverage transfer hoses, sanitary fittings (clamps, elbows, ferrules, etc.), watches, cookware sets, and more.
Machining Challenges With 316L Stainless Steel
While 316L can mitigate premature or accelerated corrosion under toxic environments, it can equally challenge fabricators during the machining process.
The alloy can resist strain hardening when you use low speed, feed, and doc (depth of cut). Otherwise, high strain may lead to high shear forces. The material enters a work hardening state where thermal softening has a negligible influence. Further adding excellent ductility into the equation, the machinability of 316L stainless steel can become challenging for fabricators, as gummy chips and workpiece material tend to build up on the tool edge. This requires more cutting force with each pass and produces high heat due to increased friction between the tool and the workpiece. As 316L has poor thermal conductivity, the excess heat dissipates through the tool, resulting in complete tool failure.
This can prove challenging for small shops and fabricators that lack high-end cutting tools and sawing setups. To leverage numerous time and cost benefits, it’s wise to outsource machining to a metal expert with precision sawing capabilities.
Your Local Supplier of Precision-Cut Stainless Steel
Industrial Metal Service has been offering a wide range of stainless steel alloys to fabricators and metal shops in the San Francisco Bay Area and nationwide for more than two decades. We also have dedicated metal sawing setups to quickly and precisely cut challenging alloys, like 316L stainless steel, into the required dimensions.
Our MetlSaw NF12-T12 can easily cut large, non-ferrous metals up to 12 feet long and 12 inches thick while holding tolerances up to ± 0.065″. Our Amada PCSAW 530 X band saw with pulse cutting technology also gives us the capability to cut specialty metals like titanium to precise tolerances.
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