SMO 254 Round Bar | UNS S31254 | DIN 1.4547

UNS S31254 Round Bar Stockist, 1.4547 Round Bar Distributor, ASTM A923 SS SMO 254 Round Bar Supplier, ISO 15156 Round Bar Exporter, ASTM A479 SS SMO 254 Round Bar Manufacturer.

PM Industries manufactures, supplies, and stocks SMO 254 Round Bar (UNS S31254). It's a super austenitic stainless steel with approximately 20% chromium, 18% nickel, 6% molybdenum, and 0.20% nitrogen, producing a PREN consistently above 42. That places it in the same pitting resistance bracket as super duplex grades like S32750 and S32760, but in a fully austenitic structure rather than the duplex two-phase structure. For applications where austenitic behavior is preferred over duplex, particularly where cryogenic toughness, non-magnetic properties, or specific fabrication characteristics favor a single-phase structure, SMO 254 provides super duplex-level corrosion resistance in a fully austenitic form.

ASTM A479 SS SMO 254 Round Bar, 1.4547 Round Bar, ASTM A923 SS SMO 254 Round Bar, UNS S31254 Round Bar.

The 6% molybdenum content is the defining compositional feature. It's what separates 6Mo super austenitic grades from standard 316L (2% Mo) and even from 317L (3.2% Mo) in chloride pitting resistance. At that molybdenum level, combined with high chromium and nitrogen, SMO 254 resists pitting in environments that rapidly attack grades with lower PREN values.

Seawater pitting resistance is where SMO 254 most clearly demonstrates its advantage over standard and even moderately alloyed stainless grades. At the critical pitting temperatures relevant to seawater service, 316L, 317L, and standard duplex grades all show localized attack at temperatures well below the boiling point. SMO 254 handles seawater reliably at temperatures that eliminate those grades from consideration, which is why it's specified for seawater-cooled heat exchangers and desalination equipment where operating temperatures push the limits of lower-PREN alloys.

Chloride stress corrosion cracking resistance is excellent. The fully austenitic structure might suggest susceptibility to SCC compared to duplex grades, but the very high nickel content places SMO 254 well above the composition threshold where austenitic stainless steels show practical SCC resistance in hot chloride environments. That high nickel content is what allows it to resist SCC in seawater and chloride process streams at temperatures where lower-nickel austenitic grades fail.

Acid resistance is good across a range of environments. In phosphoric acid, sulfuric acid at moderate concentrations, and mixed acid service, SMO 254 performs reliably. The combination of high molybdenum and chromium provides useful protection in both reducing and mildly oxidizing acid conditions.

Weldability requires matching filler metal. ERNiCrMo-3 (625) or 6Mo-matching filler is used to maintain corrosion resistance through the weld zone. With correct procedure, SMO 254 fabricates into welded vessels, heat exchangers, and piping systems without significant compromise of corrosion performance in the weld and heat-affected zone.

Bar is available in a range of diameters and surface finishes with full material certification to ASTM A276, ASTM A479, and applicable specifications. Contact PM Industries for stock availability, dimensions, and pricing.

Specification SMO 254 Round bar

Specification	ASTM, EN, DIN, JIS, BS, ASME, AISI
Condition	Hardened & tempered, annealed
Length	1 to 6 Meters, Custom Cut Lengths
Round Bars	Outside Diameter in the range of 4mm to 500mm above as per the customer requirement.
Bright Bars	Outside Diameter in the range of 4mm to 500mm above as per the customer requirement.
Hex Bars	18mm – 57mm (11/16″ to 2-3/4″) above as per the requirement.
Square Bars	18mm – 47mm (11/16″ to 1-3/4″) above as per the requirement.
Flat Bars	1/2” to 10” in thickness range of 2mm to 150mm
Finish	Black, Bright Polished, Rough Turned, NO.4 Finish, Matt Finish, BA Finish
Technique	Hot Rolled, Cold Rolled, Cold Drawn, Forged Round Bar, Rod
Tolerance	H8, H9, H10, H11, H12, H13, K9, K10, K11, K12 or as per clients’ requirements
Test Certificates	EN 10204/3.1B, NACE MR0103, NACE MR0175
Raw Materials Certificate	100% Radiography Test Report
Inspection	Third Party Inspection Report, etc

Available Types

Equivalent Grades SMO 254 Round Bar

STANDARD	WERKSTOFF NR.	UNS	JIS	SIS	GOST	AFNOR	EN
SMO 254	1.4547	S31254	-	2378	-	Z1 CNDU 20.18.06Az	X1CrNiMoCuN20-18-7

Chemical Composition of SMO 254 Round Bar

Grade	%	Ni	Cr	Mo	Cu	N	C	Mn	Si	P	S
SMO 254	Min.	17.5	19.5	6	0.5	0.18
	Max.	18.5	20.5	6.5	1	0.22	0.02	1	0.8	0.03	0.01

Mechanical Properties of SMO 254 Round Bar

Element	Density	Melting Point	Tensile Strength	Yield Strength (0.2%Offset)	Elongation
SMO 254	8.0 g/cm3	1320-1390 ℃	650	300	35 %

Stainless Steel SMO 254 Round Bar Size

US Bar		Metric		Japanese		Canadian/ASTM
Diameter (Inch)	Size of Bar	Diameter (milimeter)	size of Bar	Diameter (milimeter)	size of Bar	Diameter (milimeter2)	size of Bar
0.375	#3	5.5	5.5	10	10	200	15M
0.25	#2	5	5	6	6	100	10M
0.625	#5	7	7	16	16	500	25M
0.5	#4	6	6	13	13	300	20M
0.875	#7	9	9	22	22	1000	35M
0.75	#6	8	8	19	19	700	30M
1.125	#9	11	11	29	29	2500	55M
1	#8	10	10	25	25	1500	45M
1.375	#11	14	14	35	35
1.25	#10	12	12	32	32
1.625	#13	18	18	41	41
1.5	#12	16	16	38	38
1.875	#15	22	22	48	48
1.75	#14	20	20	44	44
2.25	#18	28	28	57	57
2	#16	25	25	51	51
		36	36
		32	32
		44	44
		40	40
		50	50

Condition

ANN	Annealed
H&T	Hardened and tempered.
PH	Precipitation hardened.

Finish

Bright drawn	BD	Slit rolled edge	SRE
Cold drawn	CD	Polished	P
Peeled and turned	P&T	Rough turned/peeled	RT
Cold finished	CF	Hot rolled pickled and annealed	HRAP
Centreless ground	CG	Hot finished	HF
Smooth turned	ST	reeled and Peeled	PR

Available Stock of SMO 254 Round bar

MS Annealed Round Bar	JIS G3101 SS400 Shafting Round Bar
UNS C36000 Normalized Round Bar	MS Automotive Round Bar
EN 10025 S235JR Quenched & Tempered Round Bar	UNS C36000 Aerospace Round Bar
2.0401 Solution Annealed Round Bar	EN 10025 S235JR Oil & Gas Round Bar
ASTM A36 MS Hardened Round Bar	2.0401 Marine Round Bar
DIN 17100 St37 Bright Round Bar	ASTM A36 MS Medical Grade Round Bar
BS 4360 Grade 43A Polished Round Bar	DIN 17100 St37 Hot Rolled Round Bar
JIS G3101 SS400 Mirror Finish Round Bar	BS 4360 Grade 43A Cold Drawn Round Bar
MS Pickled & Passivated Round Bar	JIS G3101 SS400 Cold Rolled Round Bar
UNS C36000 Coated / Plated Round Bar	MS Forged Round Bar
EN 10025 S235JR Commercial Round Bar	UNS C36000 Peeled Round Bar
2.0401 Precision Round Bar	EN 10025 S235JR Turned Round Bar
ASTM A36 MS Straight Length Round Bar	2.0401 Ground Round Bar
DIN 17100 St37 Cut-to-Length Round Bar	ASTM A36 MS Centreless Ground Round Bar
BS 4360 Grade 43A Structural Round Bar	DIN 17100 St37 Precision Ground Round Bar