Austenitic Cr-Ni-Mo stainless steel
31254 is characterized by:
- Excellent resistance to stress corrosion cracking, pitting and crevice corrosion
- Resistant to intergranular corrosion in the temperature range up to 400°C (752°F)
- For optimum resistance, surfaces should be pickled, scale free , heat treated or machined
Additional Information About Austenitic 31254 Stainless Steel
Stainless steels come in many varieties. The one overlying factor common to all steels is their ability to become corrosive. By the 1930s, duplex stainless steel was developed in Sweden for use in the paper sulfite industry. Due to chemical processes and Chloride-bearing cooling waters, stainless steel up to this time had a big decomposition problem. By the 1970s, duplex stainless steel was being used in a high number of applications. The corrosion factor was greatly reduced by the use of equal parts of austenite and ferrite. Depending on their alloy content, duplex stainless steels are a family of steel grades where corrosion is kept to a minimum.
By the 1980s, the term “Super Duplex” was coined to describe highly alloyed, high-performance Duplex stainless steel. Along with Duplex and Super Duplex stainless steels, came high alloy austenitic 31254.
254SMO, also known as alloy 31254 is an austenitic steel designed for maximum effectiveness against pitting and crevice corrosion. High alloy austenitic 31254 is especially suited for high chloride environments. It is used in many marine applications, including brackish water, seawater, pulp mill bleach plants, and other high-Chloride environments. And stainless steel 31254 is especially effective in environments containing halide ions, e.g. Chloride, Bromide and Fluoride solutions.
Alloy 31254 has been found to be highly cost-effective, as well, and is a great substitute for Nickel-based alloys and Titanium. It is a technically adequate stainless steel.
The chemical composition of High Alloy Austenitic 31254 is:
Stainless steel 31254 is an austenitic stainless steel compatible with other common austenitic stainless steels. With high levels of Chromium, Molybdenum, and Nitrogen designed to combat pitting and crevice corrosion, alloy 31254 is materially stronger than the common austenitic grades. Two of its many characteristics are high resiliency and impact strength. Stainless steel 31254 also has the ability to withstand high temperatures and to maintain its strength under unstable conditions.
When a material grade is specified as stainless steel, it means it has a chromium content within it. Alloy 31254 has high chromium content. Key features of High Alloy Austenitic 31254 are as follows:
- High alloy additions mean that it has a Pitting Resistance Equivalent number (PREN) of ≥42
- Superior corrosion resistance in seawater and concentrated halide environments
- High counteraction to stress corrosion cracking
- Resistant to crevice corrosion in seawater
- Good safeguard to erosion corrosion
- Excellent ductility and impact strength at both ambient and sub-zero temperatures
- Low magnetic permeability
The high alloy additions to alloy 31254 establish a strength that is nearly twice that of 3xx austenitic stainless steels. Just like 3xx alloys, Alloy Austenitic 31254 can be welded in the same ways.
Because corrosion has always been the biggest problem encountered in stainless steels, whether they are Duplex, Super Duplex or Alloy, here are the different definitions of where corrosion occurs:
- Pitting Corrosion. When chemical processes attack the passive layer of stainless steel, pitting can occur. The Chloride ion CL- is the most common element, and it is found in things such as bleach and salt.
- General Corrosion. Stainless steel does not corrode uniformly, even under normal conditions. The passive layer may be attacked at first, due to temperature or concentration, especially through acids. When this happens, the metal loss is evenly distributed over the entire surface.
- Crevice Corrosion. A degree of oxygen is required on the passive layer for corrosion to form on stainless steel. Where there are very tight spaces, the oxygen will have trouble gaining access to the surface, and this is how corrosion occurs in the crevices.
- Stress Corrosion Cracking. This rare type of corrosion is presented due to the combination of tensile stress, temperature and corrosive species, usually from the chloride ion.
- Intergranular Corrosion. This is a rare type of corrosion, which occurs during welding.
- Galvanic Corrosion. This type of degeneration occurs when two metals that are divergent come together. Corrosion is then speeded up in the lesser of the two metals.
The available forms of Stainless Steel Alloy 31254 are:
- Round bars
- Seam welded and cold redrawn
- Seam welded, cold redrawn and annealed
Applications where High Alloy Austenitic 31254 are found:
- Elevated oil distillation columns
- Exhaust gas desulfurization scrubbers
- Industrial components for oil and gas
- Industrial components for food processing
- Saltwater handling
- Flanges & manifolds
- Industrial components for chemical industry
- Bleaching equipment in the pulp and paper industry
- Heat exchangers
For those looking to work with stainless steels with better resistance to corrosion, Austenitic 31254 may make a wise choice, as it has the benefit of being cost-effective, as well. For more information about our products and services, contact one of our experienced professionals at Metals 28 at 708-375-5617.