An alloy is the combination of metallic elements to create greater strength and corrosion resistance. At Stainless Structurals our focus is on the different stainless steel alloys and their applications.
Stainless Steel Alloys and their Elements
Most people know that stainless steel is known for its corrosion resistance. Furthermore, it is widely used for its durability, strength, and aesthetic look. What most do not know is, what elements give stainless steel these distinct characteristics.
The three major elements of stainless steel are iron, carbon and chromium. Stainless can also contain other elements including nickel, molybdenum, and titanium. It is this combination of elements that make up the distinct alloys of stainless steels available today.
Importance of Chromium
The defining element of stainless compared to carbon steel is the presence of chromium (Cr). The chromium content can range from a minimum of 10.5 percent up to 27 percent. Oxidation passivates chromium and it forms a thin protective surface layer which prevents corrosion and rust. Thus the name stainless steel. Overall, metal alloys account for over 85 percent of the total use of chromium.
Stainless emerges when chromium and iron melt together. Chromium is such an important alloying material due to its strengthening effect and for providing a strong increase in corrosion resistance. Chromium also has a higher hardness and it is a good surface coating. It is the most popular metal coating used today.
Alternate Stainless Steel Alloys Available from Stainless Structurals
When it comes to metal fabrication, design and engineering, everyone knows about the most popular stainless steel alloys being used like 304/L, 316/L and duplex stainless steel There are also several other stainless steel alloys that one can use in a number of applications and provide many benefits. These alloys can turn into structural shapes and special shapes by the many production methods available at Stainless Structurals America. In all of the alloys detailed below, we can produce our standard stainless steel profiles like stainless steel beams, channels, angles, stainless steel tees and hollow sections as well as custom and special profiles.
These are just some of the stainless steel alloys we can produce in:
317/L is an austenitic stainless steel with an increase of nickel, chromium, and molybdenum to provide better corrosion resistance and a higher resistance to chemical effects from acids. The lower carbon content in this alloy allows for resistance to intergranular corrosion and a higher tensile strength at elevated temperatures. 317/L is weldable but it is more difficult to machine than either 304 or 316 stainless steel. Other applications for this alloy include chemical plants, textiles, petrochemical processing, food processing, and pulp and paper.
Alloy 321 is an austenitic stainless steel that is similar to 304 in corrosion resistance and weldability. 321 is harder to form than most austenitic grades because of its spring back effect. The benefit of 321 is that it has added titanium of five times the carbon content which prevents carbide precipitation during welding. High temperature applications are the general usage of this alloy. Other applications for this alloy include chemical processing, aircraft engines, oil and gas, and expansion joints.
Alloy 254 SMO is a high-end austenitic stainless steel with higher molybdenum and nitrogen with a lower carbon content. This alloy combines strength nearly twice the level of the 300 series stainless steels and outstanding resistance to pitting, stress corrosion cracking, and crevice corrosion. In some instances, 254 SMO is a better and more cost-effective solution than high nickel or titanium alloys. You can frequently find this alloy in high chloride and marine environments. Other applications for this alloy include chemical and food processing, petroleum production, oil and gas, saltwater applications, and the desalination processes.
904L is a super-austenitic stainless steel alloy that provides moderate to high corrosion resistance in many different environments. 904L has very good weldability characteristics but this alloy does not machine very well. With a high nickel and chromium content, this alloy has strong stress corrosion cracking, pitting, and overall corrosion resistance. This alloy was originally designed for the use in chemical processing applications. Other applications for this alloy include oil and gas, pulp and paper, pharmaceuticals, and heat exchangers.
Alloy AL6XN is a super-austenitic stainless steel that is low-carbon and nitrogen bearing for high purity. The original intention to design this was the usage as a seawater resistant material. AL6XN is also useful for other corrosive environments. This alloy offers very high strength and corrosion resistance making it a good, if not even better choice than the duplex stainless steels, although the costs are higher than duplex. However, AL6XN is more cost-effective than the nickel alloys. Other applications for this alloy include marine environments, offshore oil and gas, chemical processing, heat exchangers and desalination plants.
309 stainless steel is an austenitic grade with high chromium content and low nickel content. This alloy is generally used in elevated temperature applications. Some of the beneficial characteristics of 309 is its high corrosion resistance, high heat resistance, and resistance to oxidation. This alloy also has good fabrication and weldability characteristics. Other applications for this alloy include high heat applications like heat exchangers and boilers, aircraft parts, automobile industry, refineries, and chemical processing.
Alloy 310S is a high-alloyed austenitic steel designed specifically for elevated temperature applications. Some of the beneficial characteristics include good corrosion resistance, high-strength in elevated temperatures, and excellent oxidation resistance. With its high nickel and chromium content this alloy is superior to 304 or 309 in most applications. 310S also has good weldability. Other applications for this alloy include furnace parts, heat exchangers, furnace conveyors, and you can also use it as welding filler wire.
We are Here for your Next Stainless Steel Alloy Design
At Stainless Structurals we recognize the need for the availability of alternate stainless steel alloys other than 304/L, 316/L, or Duplex stainless steel. These alloys can be the difference in approving an engineer’s design or an industrial application that works. With our production technologies, we can make stainless steel alloyed sections tailored for your needs. Let us help you whith your next job Contact us today to find out more about stainless steel alloys and structural shapes.