Super Duplex 32760
Ferrite-Austenitic stainless steel
32760 is characterized by:
- Excellent corrosion resistance against general corrosion, stress corrosion cracking, corrosion fatigue, pitting, crevice and erosion corrosion.
- Possessing very high mechanical strength properties
- Good weldability, post weld heat treatment not necessary
- Max temperature for long periods of service 280°C (536°F)
Additional Information About Super Duplex 32760
Today, there are wide varieties of stainless steel. By the 1930s, stainless steels were developed in Sweden for use in the paper sulfite industry. Corrosion problems were starting to set into the steel back in the day, caused by Chloride-bearing cooling waters and other chemical process fluids that acted aggressively. Duplex stainless steels were developed by the 1970s. These featured a mixed micro-structure composed of about equal proportions of ferrite and austenite.
Depending on their alloy content, duplex stainless steels are a family of steel grades, with different corrosion performances. In the 1980s, the term “Super Duplex” was used to connote highly, alloyed, high-performance Duplex steel.
Super Duplex 32760 Stainless Steel
Super Duplex 32760, for instance, is a stainless steel that provides outstanding resistance to acids, acid chlorides, caustic solutions, and other elements in industries such as the petrochemical/chemical, and pulp and paper. This Super Duplex stainless steel replaces the 300 series stainless steel, as well as high nickel austenitic steels and nickel-based alloys.
The chemical composition of a Super Duplex steel comprises:
Throughout the years, both Duplex and Super Duplex stainless steels have enjoyed increasing popularity. The chemical compositions of Super Duplex 32760, which include Chromium, Nickel, and Molybdenum, improves intergranular and pitting corrosion resistance. With the addition of Nitrogen into the mix, additional hardening of the steel was achieved. This, in turn, raised the yield strength and ultimate overall strength without compromising toughness.
Because super duplex stainless steel is comprised of equal parts of austenite and ferrite, there is now higher resistance to pitting and stress corrosion cracking, which was a big problem in conventional stainless steels.
Alloy 32760 is a super duplex stainless steel which is supplied in the hot work and solution annealed condition. Because it is a super duplex stainless steel, it combines the best of the austenitic and ferritic worlds. It enjoys all of the features of the basic super duplex steels.
Key features of Super Duplex 32760 include:
- Excellent corrosion safeguard in a wide variety of corrosive chemicals
- Critical Pitting temperature exceeding 50°C
- Excellent resistance to pitting and crevice corrosion in seawater and other environments containing Chloride
- Pitting Resistance Equivalent number (PREN) of >40
- High strength when compared to austenitic and 22%Cr duplex stainless steels
- Outstanding resistance to abrasion, erosion, cavitation corrosion
- Superlative ductility and impact strength at both sub-zero and ambient temperatures
- ASME Approval for Pressure Vessel application
Wide and diverse applications where Super Duplex 32760 is used:
- Tankers for the oil and chemical industries
- Equipment used in organic and fatty acids
- Shipbuilding and marine industry propellers, rudders, shafts, shaft seals, bolts, fasteners, pumps, valves, and instrumentation
- Components found in dioxide, nitric acid, caustic evaporators, polypropylene and PVC production
- Components of pollution control systems, wet scrubbers, fans and pumps, incinerators, flue gas desulfurization
- Fertilizers found in agrochemical production
- Desalinization plants, sewage treatment, seawater cooling
- Food industry operations including sugar cane centrifuges, corn and vegetable processing plants
- Equipment found in the oil and gas industries, such as pipes, vessels, pumps, valves, wellhead equipment, and subsea equipment
- Components found in the pulp and paper industries, including black liquor heater tubes, digester blow valves, rotary feed valves, I.D. fans, brown stock washers, precipitators, and bleaching components
Super Duplex 32760 stainless steel displays high-impact strength at sub-zero temperatures, as well as excellent corrosion resistance. This type of super duplex stainless steel is suitable for very harsh environments as it is a cost-effective stainless steel.
Alloy 32760 consists of approximately 40-50% ferrite in the annealed condition. This means it is not uncommon to see this metal used as a sensible solution to stress cracking brought on by the presence of chloride. You might say Chloride-induced stress cracking is the Achilles’ heel of all stainless steel. Even under welding conditions, Super Duplex 32760 holds up well. Its impact strength is only slightly lower.
This type of steel was developed for pump applications in the North Sea as a solution for seawater resistant materials. It was such a success there, that it soon followed that this stainless steel would be used in many other applications as well. Subsea pipe system, oil and gas industries and so many more benefit from super duplex 32760 alloy.
Whereas duplex stainless steel is characterized by high resistance to stress corrosion cracking in Chloride-bearing environments, super duplex stainless steel offers excellent resistance to stress corrosion cracking in Chloride-bearing environments. Duplex stainless steel has high mechanical strength, but super duplex stainless steel has very high mechanical strength. Both offer good weld-ability.
Therefore, for weld-ability with better resistance to stress corrosion cracking (in chloride-bearing environments) and superior mechanical strength, Super Duplex 32760 can give you the edge you need. Speak with one of our experienced team members at Metals 28 for more information about our services and products.