Properties of Super Duplex Stainless Steel S32750

Overview of UNS S32750

Super Duplex UNS S32750 is the most common super duplex grade in the market. UNS S32750 is a duplex stainless steel especially designed for service in aggressive chloride-containing environments with high mechanical strength. UNS S32750 or 2507 Duplex is a super austenitic premium stainless that is similar to 2205 Duplex. Super Duplex UNS S32750 is composed of 25% Chrome and 7% nickel which causes the alloy to have an even higher corrosion resistance and longer life span. Along with it being corrosion resistant, UNS S32750 has a high resistance of cracking and pitting, and the yield and tensile strength make it comparable to nickel alloys.

Super Duplex steel S32750 is a super duplex stainless steel supplied in the solution annealed condition. As a super duplex stainless steel, it combines the desirable aspects of both austenitic and ferritic grades. The higher chromium, molybdenum and nitrogen contents result in a Pitting Resistance Equivalent number (PREN) of >41, providing pitting and crevice corrosion resistance superior to austenitic and duplex stainless steels in almost all corrosive media, and a Critical Pitting Temperature exceeding 50°C.

Supplied in the annealed condition, it achieves yield strengths of 80ksi (550Mpa), greater than most austenitic and duplex stainless steel grades. Super Duplex Steel UNS S32750 cannot be hardened by heat treatment but can be strengthened by cold working. It also exhibits a low coefficient of thermal expansion and higher heat conductivity than austenitic steels and is suitable for working temperatures up to 300°C. Alloy 32750 is listed in NACE MR 0175 for sour service and having gained ASME Approval for Pressure Vessel applications it can be used in a wide variety of applications.

Stainless steel Super Duplex 2507 is designed to handle highly corrosive conditions and situations were high strength is required. High molybdenum, chromium and nitrogen content in Super Duplex 2507 help the material withstand pitting and crevice corrosion. The material is also resistant to chloride stress corrosion cracking, to erosion corrosion, to corrosion fatigue, to general corrosion in acids. This alloy has good weldability and very high mechanical strength.

Chemical Composition (%) of 2507 Duplex Stainless Steel

Alloy 2507 (UNS S32750) is a super duplex stainless steel with 25% chromium, 4% molybdenum, and 7% nickel designed for demanding applications which require exceptional strength and corrosion resistance, such as chemical process, petrochemical, and seawater equipment. The steel has excellent resistance to chloride stress corrosion cracking, high thermal conductivity, and a low coefficient of thermal expansion. The high chromium, molybdenum, and nitrogen levels provide excellent resistance to pitting, crevice, and general corrosion.

Physical Properties of Super Duplex S32750

The physical properties of S32750 Super Duplex include high strength, high yield strength, and exceptional formability and weldability. These pipes have a 7.8 g/cm³ density and a melting point of 1350-1400°C. The thermal conductivity of these pipes is relatively low, which makes them suitable for high-temperature applications.

Mechanical Properties of Super Duplex S32750

Stainless steel Super Duplex S32750 exhibit exceptional mechanical properties, making them ideal for demanding applications. They offer high yield strength, tensile strength, and excellent toughness even at low temperatures. Some of the key mechanical properties of Super Duplex S32750 include a minimum tensile strength of 795 MPa, a minimum yield strength of 550 MPa, and an elongation of 15%.

Heat Treatment of Super Duplex S32750

2507 Duplex material will be heat treated at climates ~2000°F. After heated, the substance will be pursued by a annealed solution at ~1900°F then submergence in water. 2507 is easily cold worked and has a greater strength/lower ductility than austenitic stainless grades. Super Duplex S32750 can be heat treated to improve their mechanical properties. The heat treatment procedure involves heating the pipes to a temperature range of 1020-1100°C, followed by water quenching. This process enhances the pipes’ strength, toughness, and resistance to fatigue.

Corrosion Resistance of Super Duplex S32750

Large chromium levels as well as molybdenum content of 2507 Duplex makes this material very resistant to corrosive acidic elements. It implements great resistance to chloride SCC and is preferable to 2205 Duplex in both strength and corrosive resistance. Super Duplex S32750 exhibit excellent corrosion resistance, making them ideal for corrosive environments. They offer excellent resistance to pitting, crevice corrosion, and stress corrosion cracking. These pipes are also chloride-resistant, making them suitable for seawater applications.

Applications of Super Duplex Stainless Steel S32750

Super Duplex 2507 is widely used in the following sectors

Power

Marine

Chemical

Pulp and paper

Petrochemical

Water desalinization

Oil and gas production