What is the difference between 321 and 316 stainless steel

Austenitic stainless steels are the most weldable stainless steels in existence. Capable of being put through all typical welding processes, they are at risk of only a few problems, the most common of which is heat cracking.

That being said, as long as proper preparation is carried out before welding, austenitic stainless steels will suffer no cosmetic or functional problems. They can be pressed and shaped to meet a variety of different of configurations. Austenitic stainless steels are some of the toughest around, capable of withstanding high-impact physical trauma over prolonged periods of time.

Possessing high tensile strength, they are highlighted by their durability. Due to their wide variety of characteristics, austenitic stainless steels are used for a wide variety of applications.

The vast majority of manufacturing industries utilize them in some way or another. Alloy is used in everything from cutlery, to kitchen sinks, to storage tanks, and much more. Alloys and are very common in the chemical processing industry, as they are often used to make pipes, valves, and more.

Alloy has use in furnaces, fluidized bed furnaces, paper mill equipment? As we can see in the table below the temperature reduction factors are slightly higher for than for L at most elevated temperatures:. Download the guide. Disclaimer: The info presented here has been compiled from sources believed to be reliable. No guarantee is implied or expressly stated here and the data given is intended as a guide only. To print, please click here. Penflex Client Login Please login to access exclusive content available only to authorized Penflex clients.

Please login to access exclusive content available only to authorized Penflex clients. Register for Access Forgot Your Password? The series austenitic stainless steels are a set of iron-based chromium-nickel alloys designed to resist corrosion. This in combination with excellent formability, resistance to wear, and strength at temperature make them common materials of construction within piping systems.

Differences between the alloys are slight but deliberate. While they can be used interchangeably in many applications, sometimes there is an ideal solution. Substitutions in such situations could mean compromised service life. As corrosion resistance is one of the primary reasons end users opt for metal hose, application media typically guides alloy selection. For this reason, most Penflex hoses are made using or L. Braid is usually L as it will not be in contact with flow media, though L is an option if the application is in a corrosive environment—like in, on or near the ocean—or if the outside of the hose will be subject to corrosive media via drips, spray, run-off, etc.

The chart below shows the chemical composition of the most common series stainless steels used in the metal hose industry. Single figures signify the maximum percentage allowable under ASTM requirements.

Organic media or weakly corrosive aqueous agents, mil and other dairy products, or atmospheric conditions rarely produce intergranular corrosion even when large amounts of precipitated carbides are present.

Experience gained in a wide range of service conditions has provided sufficient data to generally predict the possibility of intergranular attach in most applications. Stress Corrosion Cracking The Type austenitic stainless steel is susceptible to stress corrosion cracking SCC in halides similar to Type stainless steel. This results because of their similarity in nickel content.

Stresses may result from cold deformation during forming operations, or from thermal cycles encountered during welding operations. Stress levels may be reduced by annealing or stress-relieving heat treatments following cold deformation.

Type is a good choice for service in the stress-relieved condition in environments which might otherwise cause intergranular corrosion for unstabilized alloys. Type is particularly useful under conditions which cause polythionic acid stress corrosion of non-stabilized austenitic stainless steels such as Type Exposure of non-stabilized austenitic stainless steel to temperatures in the sensitizing range will cause the precipitation of chromium carbides at grain boundaries.

On cooling to room temperature in a sulfide-containing environment, the sulfide often hydrogen sulfide reacts with moisture and oxygen to form polythionic acids which attach the sensitized grain boundaries. Under conditions of stress, intergranular cracks form. Polythionic acid SCC has occurred n oil refinery environments where sulfides are common.

The stabilized Type alloy offers a solution to polythionic acids SCC by resisting sensitization during elevated temperature service. For optimum resistance, these alloys should be used in the thermally stabilized condition if service related conditions may result in sensitization.

Generally, ppm chloride in aqueous environments is considered to be the limit for both the unstabilized and the stabilized alloys, particularly if crevices are present.

Higher levels of chloride ion might cause crevice corrosion and pitting. However, exposure of these alloys to salt mists from the ocean would be expected to cause pitting and crevice corrosion accompanied by severe discoloration. The Type alloy is not recommended for exposure to marine environments.