DUPLEX STEEL VALVES (F51/S31803/2205/CD3MN)

Duplex stainless is a mixed microstructure of austenitic and ferrite (50/50) which has improved strength over ferritic and austenitic steel grades with similar corrosion resistance qualities.

Global Supply Line offers valves ex stock and on an indent basis in duplex stainless steel materials such as forged ASTM A182-F51 cast A995 Grade 4A (formerly A351-CD3MN and ASTM A351 CE8MN/CD4MCuN). Other grades are exotic and special stainless steels such as Super Duplex forged A182 F53 and A182 F55 and it’s cast equivalent A995 Grade 6A (formerly CD3MWCuN). A182 F44 and it’s equivalent A351 CK3MCuN are available upon request. Duplex A182-F51 is equivalent to:- UNS31803† and DIN 1.4462 and it is similar to:- 329LN, SAF2205, Uranus 45N.

Benefits of using Duplex Stainless Steel

Similar corrosion resistance to Type 316
Greater tensile and yield strength
Good ductility and toughness
Good stress corrosion cracking resistance (SSC)

Duplex stainless steel is designed to combine improved resistance to stress corrosion cracking (including sulfide stress corrosion cracking), pitting, crevice corrosion and high strength when compared with other stainless alloys. This alloy resists chloride environments and sulfide stress corrosion. It is also roughly double the strength of standard austentic stainless steels.

Applications

Petrochemical
Desalination plants
Chemical processing and transportation
Chloride-handling industries
Valve stems

Equivalent Grades

*S31803 has been supplemented by S32205 which has a higher minimum N, CR and Mo
A995 optionally supersedes A990 (1A and 1C are not referenced in A995) ASME B16.34 now only references A995. A890 is no longer used for pressure retaining castings.

ASTM GRADE	A351/A990-1A*	A995-1B	A990-1C*	A995-2A	A995-3A	A995-4A	A995-5A	A995-6A	A995-7A	A351/A990*
Type	25Cr5NiMoCu	25Cr5Ni2Mo3Cu	25Cr6NiMoCuN	24Cr10Ni4MoV	25Cr5NiMoV	22Cr5Ni3MoN	25Cr7Ni4MoN	25Cr7Ni3.5MoWCb	27Cr7Ni-Mo-W-N	25Cr7Ni3.5MoWCb
UNS No.	J93370	J93372	J93373	J93345	J93371	S31803/S32205†	S32750	S32760		S31254
ASTM No.	A351-CD4MCu① (A990 1A)*	A995① CD4MCuN-1B	A990-CD3MCuN/1C*	A995-2A/CE8MN① A351-CE8MN	A995-CD6MN-3A	A995-CD3MN-4A	A995-CE3MN-5A	A995① CD3MWCuN-6A	A995-CD3MWN-7A	A351-CK3MCuN A990* CK3MCuN
Forged Equiv.	A182-F50		F61			A182-F51	A182-F53	A182-F55	(Zeron 100^TM)	A182-F44
Common Name	Duplex	Duplex	Duplex	Duplex	Duplex	Duplex 2205	Super Duplex 32750	Super Duplex	Super Austenitic/Duplex	Super Duplex
European (DIN)						1.4462	1.4410	1.4501	UNS J93379

†S31803 has been supplemented by S32205 (F60) which dual conforms to S31803 but has a higher minimum N, MO, NI and Cr which guarantees a better corrosion resistance.
*A990 1A and 1C (CD3MCuN) is obsolete and is not referenced in A995. A990 is superceded by A995 for pressure retaining castings.
① CE8MN, CD4MCu, CD3MWCuN have been deleted from A351 and added to A995 and may be supplied in compliance with grades 2A, 1B and 6A respectively. CD4MCu was removed from A351 and replaced by A995 CD4MCuN.

Applications

FORGING SPECIFICATION	COMMON DESIGNATION	ASTM CAST	WROUGHT BAR SPECIFICATION	SERVICE RECOMMENDATIONS (1)
ASTM A182 F44	20% Chrome; 18% Nickel; 6% Mo; 0.25% C Super Stainless Steel	ASTM A351 Grade CK3MCuN (A995-1B) Super Austenitic	ASTM A479 S31254	(2.54 SMO) Acetic acid, antibiotics and drugs, bleaching compounds, formic acid, fruit and juices, hot air, hot water, hydrocarbons, hydrochloric acid, organic liquids and acids, nitric acid, organic salts, oxalic acid, phosphoric acid, sea water, sewage, sodium bisulfite, steam, sulfamic acid, 10% sulfuric acid.
ASTM A182 F50	25.5% Chrome; 5.5% Nickel; 2% Mo; 0.040% C Super Stainless Steel	ASTM A995 Grade CD4MCuN	ASTM A479 S32550	Concentrate brine, fatty acids, potable water, pulp water, pulp liquors at 220ºF (104ºC), sea water, steam, sulfuric acid (15-30% @ 140-160ºF (60-71ºC), sulfuric acid (35-40% @ 185ºF (85ºC), plus 5% organics).
	24% Chrome; 9.5% Nickel; 4% Mo; 0.080% C Duplex Stainless Steel	ASTM A995 Grade CE8MN (2A)		Concentrate brine, fatty acids, potable water, pulp water, pulp liquors at 220ºF (104ºC), sea water, steam, sulfuric acid (15-30% @ 140-160ºF (60-71ºC), sulfuric acid (35-40% @ 185ºF (85ºC), plus 5% organics).
ASTM A182 F51	22% Chrome; 5% Nickel; 3% Mo; N; 0.030% C Duplex Stainless Steel	ASTM A995 Grade CD3MN (4A)	ASTM A479 S31803**	Concentrate brine, fatty acids, potable water, pulp water, pulp liquors at 220ºF (104ºC), sea water, steam, sulfuric acid (15-30% @ 140-160ºF (60-71ºC), sulfuric acid (35-40% @ 185ºF (85ºC), plus 5% organics).
ASTM A182 F53	25% Chrome; 7% Nickel; 4.5% Mo; N; 0.030% C Super Duplex Stainless Steel Grade 5A	ASTM A995 Grade CE3MN (5A)	ASTM A479 32750	Concentrate brine, fatty acids, potable water, pulp water, pulp liquors at 220ºF (104ºC), sea water, steam, sulfuric acid (15-30% @ 140-160ºF (60-71ºC), sulfuric acid (35-40% @ 185ºF (85ºC), plus 5%organics). Useful where the Pitting Resistance Number (PREN) is required.
ASTM A182 F55	25% Chrome; 7.5% Nickel; 3.5% Mo; N; 0.030%} C Super Duplex Stainless Steel Grade 6A	ASTM A995 Grade CD3MWCuN (6A)	ASTM A479 32760	Concentrate brine, fatty acids, potable water, pulp water, pulp liquors at 220ºF (104ºC), sea water, steam, sulfuric acid (15-30% @ 140-160ºF (60-71ºC), sulfuric acid (35-40% @ 185ºF (85ºC), plus 5% organics). Useful where the Pitting Resistance Number (PREN) is required.

* No longer referenced in ASME

** S31803 has been supplemented by S32205 (F60) which has a higher minimum Ni Cr and Mo. (32205 Dual conforms to 31803)

Also see alternate Duplex Cross Reference, click here.

Applicable Standards

As well as ASTM A182 and A351 other standards such as ASTM A240, A789 and A790 also cover Duplex grades of valve bodies and trim materials.

Trade Name	UNS	Industry Specifications
SAF 2205	UNS S31803*	ASME SA-182 (F51), SA-240, SA-798, SA-790, SA-815
		ASTM A240, A276, A479, A789, A790, A815, A923, A928, A988
		SAE J405
SAF 2205	UNS S32205*	ASTM A240, A240M, A276, A479, A480, A480M, A798, A7901, A815, A923, A928, A988
		SAE J40

* UNS31803 has been supplemented by S32205 (F60) which dual conforms to S31803 but has a higher minimum N, MO, NI and Cr which guarantees a better corrosion resistance.

General Duplex Stainless Steel Information

2205 is the most widely used duplex (ferritic/austenitic) stainless steel grade. It finds applications due to both excellent corrosion resistance and high strength. The standard duplex S31803 (A182 F51) composition has been refined over many years, and the resulting composition range was endorsed as UNS S32205 in 1996. Duplex S32205 provides excellent guaranteed corrosion resistance, but it should be noted much of the Duplex S31803 currently produced also dual conforms with Duplex S32205. 2205 is not generally suitable for use at temperatures above 300ºC as it suffers from precipitation of brittle micro-constituents, nor below -50ºC because of its ductile-to-brittle-transition.