Since pricing and corrosion resistance are both equally important when deciding a grade for a particular selection. In case of Duplex and Stainless Steel 316, there is no clear winner. Metline Industries supplies high quality Duplex stainless steel 2205 rods and bars, as well as Stainless Steel 316L stainless steel bars and rods. Both grades have their special qualities, due to which they are accepted for wide range of applications across various industry verticals.

While, reading and gather information both the grades – we came across some important observations, as below:

In terms of “Corrosion Resistance” – Duplex stainless steels exhibit a high level of corrosion resistance in most environments where the standard austenitic grades are useful.However, there are some notable exceptions where they are decidedly superior. This results from their high chromium content, which is beneficial in oxidizing acids, along with sufficient molybdenum and nickel to provide resistance in mildly reducing acid environments. The relatively high chromium, molybdenum and nitrogen also give them very good resistance to chloride pitting and crevice corrosion. Their duplex structure is an advantage in potential chloride stress corrosion cracking environments. Duplex alloys are more resistant to chloride stress corrosion cracking than Types 304 and 316.

With Respect to “Pitting and Crevice Corrosion Resistance” – The high chromium, molybdenum and nitrogen contents in duplex grades provide very good resistance to chloride-induced localized corrosion in aqueous environments. All but the very lowest alloyed duplex stainless steels are far superior to Type 316 in this respect. Depending on the alloy content, some duplex grades are among the best performing stainless steels. Because they contain relatively high chromium content, duplex stainless steels provide a high level of corrosion resistance very economically. A comparison of pitting and crevice corrosion resistance for a number of stainless steels in the solution annealed condition as measured by the ASTM G 48 procedures (10% ferric chloride) is given in Figure 1. Critical temperatures for materials in the as-welded condition would be expected to be somewhat lower. Higher critical pitting ( CPT) or crevice corrosion temperatures (CCT) indicate greater resistance to the initiation of these forms of corrosion. The CPT and CCT of 2205 are well above those of Type 316. This makes 2205 a versatile material in applications where chlorides are concentrated by evaporation, as in the vapor spaces of heat exchangers or beneath insulation. The CPT of 2205 indicates that it can handle many brackish waters and de-aerated brines. It has been successfully used in seawater applications where the surface has been maintained free of deposits through high flow rates or other means. Figure 2 shows the CCT as a function of PRE number.

Metline Industries is one of the biggest steel bars and rods manufacturer and suppliers in India with more than 20 years exports and domestic sales experience. We are specialized in supplying both stainless steel duplex round bars and stainless steel 316L round bars, stainless steel angles and stainless steel flat bars with competitive price and high quality. The quality of our stainless steel bars are highly accepted in the US, UK, Saudi Arabia, Kuwait, UAE, Australia, Qatar, Bahrain, Singapore, Africa and many other countries.

Designation Various Stainless Steel Grades – Equivalents

410S 1. 4000 S41008 X6Cr13 Z8C12 Ferrite
410 1. 4006 S41000 X12Cr13 Z10C13 A182 F410 Martensite
430 1. 4016 S43000 X6Cr17 Z8C17 Ferrite
420 1. 4021 S42000 X20Cr13 Z20C13 Martensite
420 1. 4028 J91153 X30Cr13 Z33C13 Martensite
1. 4162 S32101 LDX 2101 Duplex
304 1. 4301 S30400 X5CrNi18.10 Z6CN18.09 A182 F304 Austenite
304L 1. 4306 S30403 X2CrNi19.11 A182 F304L Austenite
304L 1. 4307 A182 F304L Austenite
1. 4362 S32304/S 39230 X2CrNiN23.4 Z3CN23.04Az SAF 2304 Superduplex
316 1. 4401 S31600 X5CrNiMo17.12.2 Z7CND17.11.02   A182 F316 Austenite
316L 1. 4404 S31603 X2CrNiMo17.13.2 Z3CND18.12.02   A182 F316L Austenite
1. 4410 S32750 X2CrNiMoN25.7.4 Z3CND25.07Az SAF 2507 A182 F53 Superduplex
316L 1. 4435 S31609 X2CrNiMo18.14.3 Z3CND18.14.03 Austenite
316 1. 4436 X5CrNiMo17.13.3 Z6CND18.12.03 Austenite
317L 1. 4438 S31703 X2CrNiMo18.16.4 Z3CND19.15.04 A182 F317L Austenite
1. 4462 S31803/S32205 X2CrNiMoN22.5.3 Z3CND22.05Az SAF 2205 A182 F51 Duplex
  1. 4501 S32760 X2CrNiMoCuWN25.7.4   Zeron 100 A 182 F55 Duplex
409 1. 4512 Ferrite
904L 1. 4539 N 08904 X1NiCrMoCu25.20.5 Z2NCDU25.20 Uranus B6/2 RK 65 625 N08904 Austenite
321 1. 4541 S32100 X6CrNiTi18.10 Z6CNT18.10 Uranus 65 / SS25L A182 F321 Austenite
630 1. 4542 S17400 X5CrNiCunB17.4 Z7CNU17.04 17.4 PH A564 630
1. 4547 S31254 254Smo A182 F44 Austenite
347 1. 4550 S34700 X6CrNiTi18.10 Z6CNNb18.10 A182 F347 Austenite
316Ti 1. 4571 S31635 X6CrNiMoTi17.12.2 Z6CNDT17.12 A182 F316Ti Austenite
1. 4652 S32654 654Smo Austenite
1. 4662 S82441 LDX 2404 Duplex
1. 4713 X10CrAlSi7 Z8Ca7 Sicromal 8 Ferrite
1. 4724 X10CrAlSi13 Z13C13 Sicromal 9 Ferrite
442 1. 4742 S44200 X10CrAlSi18 Z12CAS18 Sicromal 10 Ferrite
1. 4762 X10CrAlSi24 Z12CAS25 Sicromal 12 Ferrite
1. 4818 S30415 153 MA Austenite
302 B 1. 4828 S30215/30900 X15CrNiSi20-12 A182 F309 Austenite
309S 1. 4833 S30908 X6CrNi22.13 Z15CN24.13 Austenite
1. 4835 S30815 X9CrNiSiNCe21-11-2 253 MA Austenite
310 1. 4841 S31000/31400 X15CrNiSi25.20 Z15CNS25.20 Austenite
310S 1. 4845 S31008 X12CrNi25.21 Z8CN25.20 A182 F310S Austenite
321H 1. 4878 S32109 X12CrNiTi18.9 Z6CNT18.12 Austenite
316H 1. 4919 S31609 X6CrNiMo17.13 Z6CND17.12 S31609 Austenite
304H 1. 4948 S30409 X6CrNi18.11 Z6CN18.11 S30409 Austenite