Stainless Steel 254 SMO Round Bar
➡️ 254 SMO | UNS S31254 | EN 1.4547
➡️ ASTM, EN, JIS & International Standards
➡️ Supply Conditions
➡️ Multiple Diameters & Supply Lengths
➡️ Global Export & International Delivery
Country of Origin:
Europe, Japan, USA
Material Type:
Stainless Steel
UNS Number:
S31254
Wr. No.:
1.4547
MTC Available:
EN 10204 3.1
Product Description for Stainless Steel 254 SMO Round Bar
254 SMO is a 6% molybdenum super austenitic stainless steel, designated UNS S31254 and 1.4547. The name is a registered trade mark of Outokumpu, and material is bought against the UNS number. Bar is supplied to ASTM A276 / A276M and ASTM A479 / A479M with dimensions to ASTM A484 / A484M, or to EN 10088-3 as 1.4547.
The composition is 20Cr-18Ni-6.1Mo with a controlled nitrogen addition of 0.180-0.250% and 0.50-1.00% copper. Molybdenum and nitrogen together push the pitting resistance equivalent above 42.5, which is the threshold that defines a 6Mo grade, and typical heats land around 43-45. That is enough to resist pitting and crevice corrosion in natural seawater at ambient temperature, where 316L and even 904L fail.
Nitrogen also strengthens the material, giving a minimum proof strength of 300 MPa, half again that of 316L, while the structure stays fully austenitic and tough.
Material ships solution annealed at roughly 1150-1200 C and cooled rapidly in water. The annealing temperature is high because 6% molybdenum makes intermetallic precipitation easy, and that is the single biggest risk in processing this grade.
Diameters run 8 mm to 300 mm. Annealed bar is non-magnetic and gains nothing from a hardening treatment, and cold work is the only route to more strength.
Welding uses over-alloyed nickel-base filler such as ERNiCrMo-3, since matching filler would leave the weld metal molybdenum-depleted through segregation. Machining is harder work than 316L, because the material is tough and work hardens quickly.
Typical work is seawater handling and desalination, offshore hardware, flue-gas desulphurisation, bleaching plant, heat exchangers, pump and valve components and machined fittings in chloride service.
Common Applications of Stainless Steel 254 SMO Round Bar
➡️ Machined shafts, spindles, valve stems, pump sleeves and pins for food, beverage, dairy and pharmaceutical equipment, where the passive chromium oxide film resists both product acids and caustic clean-in-place chemicals.
➡️ Fasteners, studs, bolts, threaded rod and anchor components produced from bar stock, chosen for corrosion resistance combined with the ductility needed for cold heading and thread rolling.
➡️ Chemical, water treatment and general process plant parts such as agitator shafts, flange blanks, nozzles and support components handling water, steam and mildly corrosive media free of significant chlorides.
➡️ Architectural and structural hardware including handrail stanchions, balustrade fittings, tension rods and bollards, where a bright ground or polished bar finish provides both appearance and low maintenance.
International Equivalent Grade for 254 SMO Round Bar
Standard
Country / Region
Grade
ASTM A276 / A276M
USA
UNS S31254
ASTM A479 / A479M
USA
UNS S31254
ASME SA-479
USA
UNS S31254
EN 10088-3
Europe / EU
1.4547 (X1CrNiMoCuN20-18-7)
BS EN 10088-3
United Kingdom
1.4547
JIS G4303
Japan
SUS 312L
GB/T 1220
China
015Cr20Ni18Mo6CuN (S31254)
ISO 15510
International
X1CrNiMoCuN20-18-7
Technical Specification for Stainless Steel 254 SMO Round Bar
Specification
Value
Unit
Material
Stainless steel
-
Grade
254 SMO / UNS S31254 / 1.4547
-
Product Form
Round bar / rod
-
Standard
ASTM A276 / A276M, ASTM A479 / A479M, EN 10088-3
-
Diameter
8 - 300 (typical supply range)
mm
Length
3 - 6 (random), or cut to length
m
Manufacturing Process
Hot rolled or forged, solution annealed
-
Production Route
EAF + AOD or VOD refining
-
Surface Finish
Hot-rolled and pickled, peeled, turned, centreless ground, polished
-
Heat Treatment / Delivery Condition
Solution annealed 1150 C minimum per ASTM A479, water quenched, EN condition +AT
-
Tolerance Standard
ASTM A484 / A484M, or EN 10060 / EN 10278 in European practice
-
Density
8.00 (typical)
g/cm3
Melting Range
1320 - 1390 (typical)
C
Thermal Conductivity at 20 C
14.0 (typical)
W/m.K
Coefficient of Thermal Expansion (20-100 C)
16.5 (typical)
um/m.C
Specific Heat (0-100 C)
500 (typical)
J/kg.K
Electrical Resistivity at 20 C
0.85 (typical)
uOhm.m
Modulus of Elasticity at 20 C
195 (typical)
GPa
Magnetic Properties
Non-magnetic in the solution-annealed condition
-
Pitting Resistance Equivalent (PREN)
42.5 minimum, typically 43 - 45
-
Testing / Inspection Standard
ASTM A370 for mechanical testing, ASTM G48 Method A for pitting resistance
-
Certification / Inspection Documents
EN 10204 3.1 or 3.2 mill test certificate
-
Technical Specifications
Get the key technical specifications for Stainless Steel 254 SMO Round Bar
Order to ASTM A276 / A276M or ASTM A479 / A479M under UNS S31254, or to EN 10088-3 as 1.4547 in the +AT solution-annealed condition, with ASME SA-479 for pressure-retaining components. Dimensional tolerance, straightness and surface condition follow ASTM A484 / A484M, or EN 10060 and EN 10278 in European practice.
Solution annealing at 1150-1200 C followed by a fast water quench is the controlling operation, and the temperature is deliberately higher than for ordinary austenitic grades. At 6% molybdenum, sigma and chi phases form readily between roughly 600 C and 1000 C, and even a modest amount destroys both toughness and the pitting resistance the grade is bought for. Anything that reheats the material into that band, including welding with excessive heat input, has to be controlled.
ASTM G48 Method A pitting testing is commonly specified as a supplementary requirement, and for critical seawater service it is worth making it mandatory on the order rather than optional, since it is the direct check that the anneal was done properly.
Machining is harder work than 316L. The material work hardens quickly and is tough, so rigid setups, sharp tooling, positive feeds and slower speeds are needed.
Welding uses over-alloyed nickel-base filler such as ERNiCrMo-3 or ERNiCrMo-13, because matching filler would leave the weld metal molybdenum-depleted through segregation.
Chemical Composition for Stainless Steel 254 SMO Round Bar
Element
Symbol
Min
Max
Unit
Carbon
C
-
0.020
%
Manganese
Mn
-
1.00
%
Silicon
Si
-
0.80
%
Phosphorus
P
-
0.030
%
Sulfur
S
-
0.010
%
Chromium
Cr
19.50
20.50
%
Nickel
Ni
17.50
18.50
%
Molybdenum
Mo
6.00
6.50
%
Copper
Cu
0.50
1.00
%
Nitrogen
N
0.180
0.250
%
Iron
Fe
Balance
-
%
Chemical Composition
View the chemical composition and applicable material limits for 254 SMO Round Bar
Molybdenum at 6.00-6.50% is what puts this grade in the super austenitic class. It strengthens the passive film against localised breakdown, and at this level the material resists pitting and crevice corrosion in natural seawater at ambient temperature, which ordinary molybdenum-bearing grades cannot manage.
Nitrogen at 0.180-0.250% is a deliberate addition doing three jobs at once. It contributes powerfully to pitting resistance, weighted sixteen times in the pitting resistance equivalent calculation. It strengthens the austenite interstitially, giving a proof strength half again that of 316L. And it stabilises the austenite against the ferrite-forming pull of all that molybdenum.
Chromium at 19.50-20.50% forms the passive film and carries the base of the pitting resistance equivalent. Nickel at 17.50-18.50% has to be high to keep the structure fully austenitic against 6% molybdenum, and it supplies toughness and chloride stress corrosion cracking resistance.
Copper at 0.50-1.00% improves behaviour in reducing acids, particularly sulphuric.
Carbon is capped at 0.020% and sulphur at a tight 0.010%, both well below ordinary austenitic limits, to protect corrosion resistance and hot workability in a grade that is difficult to process.
Mechanical Properties for Stainless Steel 254 SMO Round Bar
Mechanical Property
Value
Unit
Tensile Strength
650
MPa (minimum, ASTM A479)
Yield Strength 0.2% Proof
300
MPa (minimum, ASTM A479)
Elongation in 50 mm
35
% (minimum, ASTM A479)
Hardness
223
HBW (maximum, ASTM A479)
Hardness
96
HRB (maximum, ASTM A479)
Modulus of Elasticity
195
GPa (typical)
Mechanical Properties
Check the key mechanical properties and performance requirements of 254 SMO Round Bar
The values apply to solution-annealed bar under ASTM A479 / A479M and are minima, except hardness, which is a ceiling. Testing follows ASTM A370 on material as delivered.
Nitrogen strengthening lifts the minimum proof strength to 300 MPa, against 205 MPa for annealed 316L, and minimum tensile strength to 650 MPa. That is a useful bonus rather than the reason anyone buys the grade, but it does allow lighter sections than a standard austenitic design would need.
Ductility stays high at 35% minimum elongation. The structure is fully austenitic with no ductile-to-brittle transition, so impact toughness holds down to cryogenic temperatures.
Heat treatment will not harden the alloy, and cold work is the only route to more strength, at the usual cost in elongation.
The mechanical figures also serve an indirect purpose worth knowing. If a heat comes in hard, above the 223 HBW ceiling, that is a warning sign of intermetallic precipitation from an inadequate anneal or slow quench rather than simply a strong heat. Corrosion resistance should be confirmed by ASTM G48 testing before such material is accepted for seawater duty.
Dimension / Sizes for Stainless Steel 254 SMO Round Bar
Dimension / Size
Value
Unit
Diameter
8 - 300
mm
Standard Length
3 - 6 (random / mill lengths)
m
Custom Length
Cut to length available on request
-
Diameter Tolerance
Per ASTM A484 / A484M, varies with size and finish class
-
Length Tolerance
Per ASTM A484 / A484M or as agreed at order
-
Straightness Tolerance
Per ASTM A484 / A484M or as agreed at order
-
End Condition
Square cut, chamfered, or as ordered
-
Surface Finish
Hot-rolled and pickled, peeled, turned, centreless ground, polished
-
Available Size Range
8 - 300, larger diameters by forging on enquiry
mm
Cut-to-Length Availability
Available
-
Dimensional Standard
ASTM A484 / A484M
-
Dimensions & Sizes
Explore available diameters, lengths, and dimensional requirements for 254 SMO Round Bar
Pricing for Stainless Steel 254 SMO Round Bar
Round Bar Prices are generally quoted per kilograms or meters tonnes and can fluctuate with the global raw material and market prices. The final price will depend on a variety of factors, including the grade size, diameter, length, surface finish, the quantity and whether the bars are cut to length or in standard lengths.
For smaller quantities, we can also quote per metre or per piece basis once the required dimensions have been confirmed. Container-loads or orders that are larger in size are typically priced per tonne, based upon the specifications required and the supply conditions.
Please provide your desired dimensions, grades, length number, and end for a current quote including the lead time applicable and details for certification.
Pricing
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Why Choose Us
Euro Steel Bars is an international distributor, stockist and exporter of stainless round steel bars that cover carbon, stainless alloy, special grades. We stock a variety of sizes and grades. We guarantee every order with mill test certificates as well as full quality-assurance documentation. Our name speaks to our roots: European-sourced materials that is backed by the certificates and rigor that buyers from Asia as well as the Gulf and Africa are looking for.
Each bar we deliver is accompanied by EN 10204 3.1 mill test certificates as well as complete documentation of quality, so what you receive corresponds to what’s written in the documents. We carry a selection of sizes and grades ready for transport, and cut length upon the request of customers, which results in quicker lead times, whether you’re ordering just a one-off spec or a complete project tonnage.
We operate an actual wholesale business that is that is supported with an internationally-operated supply chain therefore we are able to serve fabricators sourcing one grade the same way in the same way as an EPC contractor who is placing a large order. Our clients include manufacturers, fabricators EPC construction companies, engineers oil and gas projects as well as construction companies. we design our inventory as well as documentation to show what buyers need to bring projects forward.
Our customers trust us across Qatar, Oman, Bahrain, Kuwait, Jordan, Malaysia, Singapore, Thailand, Taiwan, Turkey, Italy and South Africa. If you’re looking to source an Gulf energy project, or a construction project within Southeast Asia, you get the same quality of certified material, the exact documentation, and the exact delivery procedure.
Frequently Asked Questions
What is 254 SMO Stainless Steel Round Bar?
What does the 42.5 PREN figure mean?
What standard does 254 SMO Round Bar comply with?
What are the equivalent grades of 254 SMO Round Bar?
What are the key mechanical properties of 254 SMO Round Bar?
Why is 254 SMO annealed at such a high temperature?
Can 254 SMO Round Bar be welded?
What sizes and lengths are available?
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