What is 2205 Duplex Stainless Steel?
Based on a 22% chromium content, a 2205 duplex stainless steel (UNS S31803 / UNS S32205, F51 / F60, 1.4462) gets a pitting resistance equivalent number (PREN) of 34. Duplex stainless steel is often based on an alloy with 25% chromium or higher and is normally categorized as having a PREN value greater than 40. As a result, corrosion resistance is guaranteed to be strong in a variety of conditions. For applications needing long-term performance in seawater as well as many industrial and chemical process industries where there is exposure to certain acids, duplex grades are the standard specification.
The high yield strength of 2205 Duplex Stainless Steel Bolts, which is double that of normal austenitic stainless steels like 304 and 316 stainless steel bolts when they are annealed, is what distinguishes them from their counterparts. Due to this, Super Duplex 2507 and Duplex 2205 steel are two of the most often used duplex bolt grades, with Super Duplex 2507 bolts being the more corrosion-resistant of the two.
The Distinction Between Duplex and Super Duplex Fasteners
even though chromium, molybdenum, and nickel alloys are the same for both duplex and super duplex. Additionally, they contain a mixed austenite and ferrite composition, which offers them superior mechanical and physical qualities in comparison to both the austenitic and ferritic stainless steel groups. The amount of chromium and molybdenum in a duplex and super duplex steel fastener makes a significant distinction. Chromium concentration in stainless steel super duplex grades ranges from 24 to 26 percent, whereas it could range from 19 to 32 percent in stainless steel duplex grades.
Another distinction is the amount of chromium and molybdenum in duplex and super duplex steel fasteners. Super duplex stainless steel has a chromium level that ranges from 24 to 26 percent, whereas duplex stainless steel's chromium content can range from 19 to 32 percent. Another difference between duplex steel and super duplex steel is the inclusion of nitrogen. Nitrogen is added to super duplex stainless steels to boost their yield strength and pitting resistance. Nitrogen also helps to stabilize the austenite effect when nickel is present.
Properties of Duplex Stainless Steel
Duplex stainless steel typically has a strength that is double that of a conventional 3X-series austenitic stainless steel, like Alloy 316L. In contrast to alloy 316L, which has a minimum yield strength of just 25 KSI (170 MPa), 2205 duplex stainless steel has a minimum yield strength of 65 KSI (450 MPa) (UNS S31603, 1.4404).
The yield strength for a super duplex grade is even greater, at 80 ksi, for either UNS S32750 (F53, 1.4410) or UNS S32760 (F55, 1.4501). (550MPa). The strongest super duplex stainless steel is Terrarium 255-SD50 (F61, UNS S32550, and 1.4507), with a minimum yield strength of 85 KSI (586 MPa).
In addition to the previously mentioned evident benefits of these alloys, additional processing can increase their strength. Work-hardening of duplex stainless steels can enhance the yield stress and ultimate tensile strength while decreasing the elongation value.
