Stainless Steel AL6XN Round Bar
➡️ Alloy 6XN | UNS N08367 | ASTM B691
➡️ 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:
N08367
Wr. No.:
-
MTC Available:
EN 10204 3.1
Product Description for Stainless Steel AL6XN Round Bar
AL6XN Round Bar is a solid cylindrical bar produced from super-austenitic stainless steel UNS N08367, widely known by the trade name AL-6XN, a registered trademark of ATI. Rod and bar are supplied to ASTM B691, and the alloy is also listed in ASTM A479 and ASME SB691 for pressure applications.
The alloy is a low-carbon, high-purity 6% molybdenum super-austenitic grade containing 23.50-25.50% nickel, 20.0-22.0% chromium, 6.00-7.00% molybdenum and 0.18-0.25% nitrogen on an iron balance. The combination of high molybdenum and nitrogen gives a pitting resistance equivalent number in excess of 45, far above that of Type 316L, and delivers resistance to pitting, crevice corrosion and chloride stress-corrosion cracking approaching that of nickel-base alloys at a considerably lower cost.
The nickel content of around 24% is sufficient to make the alloy highly resistant to chloride-induced stress-corrosion cracking, the failure mode that limits standard austenitic stainless steels in hot chloride service. Nitrogen also provides substantial solid solution strengthening, giving a minimum yield strength of 310 MPa, roughly 50% above Type 316L.
Bar is supplied solution annealed in diameters from about 6 mm to 250 mm and lengths of 3 to 6 m. The alloy is non-magnetic and cannot be hardened by heat treatment.
Typical applications include seawater and brackish water handling equipment, condenser and heat exchanger components, desalination plant hardware, chemical and pharmaceutical process parts, pulp and paper bleaching equipment, flue gas desulphurisation systems, offshore piping components, pump and valve shafts, and food processing equipment.
Common Applications of Stainless Steel AL6XN 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 AL-6XN Round Bar
Standard
Country / Region
Grade
ASTM B691
USA
UNS N08367 - rod, bar and wire
ASME SB691
USA
SB691 UNS N08367
ASTM A276 / A276M
USA
UNS N08367 - stainless steel bars and shapes
ASTM A479 / A479M
USA
UNS N08367 - bars for pressure vessel service
NACE MR0175 / ISO 15156-3
International
UNS N08367 for sour service subject to environmental limits
Technical Specification for Stainless Steel AL6XN Round Bar
Specification
Value
Unit
Material
Super-austenitic stainless steel
-
Grade
AL-6XN / UNS N08367
-
Product Form
Round bar / rod
-
Standard
ASTM B691 and ASTM A479 / A479M
-
Diameter
6 - 250 (available range)
mm
Length
3 - 6 (standard random or fixed)
m
Manufacturing Process
Hot rolled, forged or cold drawn
-
Production Route
EAF / AOD melting with argon oxygen decarburisation, hot working, solution annealing, water quench
-
Surface Finish
Hot-finished and pickled, peeled, rough turned, cold-drawn, ground, polished
-
Heat Treatment / Delivery Condition
Solution annealed and rapidly quenched
-
Solution Annealing Temperature
1100 - 1180 followed by water quench (typical)
deg C
Pitting Resistance Equivalent Number (PREN)
Greater than 45 (typical)
-
Critical Pitting Temperature
Greater than 45 in ASTM G48 Method A (typical)
deg C
Tolerance Standard
ASTM B691 or ASTM A484 / A484M as applicable
-
Carbon Equivalent (CEV)
Not applicable to austenitic stainless steel
-
Density
8.06 (typical)
g/cm3
Melting Range
1320 - 1400 (typical)
deg C
Thermal Conductivity
11.5 at 20 deg C (typical)
W/m.K
Coefficient of Thermal Expansion
15.2 at 20 - 100 deg C (typical)
micro-m/m.K
Specific Heat
460 at 20 deg C (typical)
J/kg.K
Electrical Resistivity
0.89 (typical)
micro-ohm.m
Modulus of Elasticity
195 (typical)
GPa
Magnetic Properties
Non-magnetic, relative permeability approximately 1.0
-
Applicable Testing Standard
ASTM E8 / E8M, ASTM E18, ASTM E1473, ASTM G48, ASTM A262
-
Certification / Inspection Documents
EN 10204 Type 3.1 or 3.2 mill test certificate
-
Technical Specifications
Get the key technical specifications for Stainless Steel AL6XN Round Bar
AL6XN Round Bar is supplied principally to ASTM B691 for nickel-iron-chromium-molybdenum alloy rod, bar and wire, adopted by ASME as SB691. The alloy is also listed in ASTM A479 / A479M for bars used in pressure vessel and boiler construction, and dimensional requirements may be taken from ASTM A484 / A484M when the material is ordered as a stainless bar.
Solution annealing is critical and is carried out at approximately 1100-1180 deg C followed by a rapid water quench. Because of the high molybdenum content the alloy is prone to precipitation of sigma, chi and Laves intermetallic phases if it cools slowly through roughly 600-1000 deg C. These phases deplete chromium and molybdenum locally and sharply reduce both corrosion resistance and toughness, so slow cooling or reheating into that range is not permitted.
The alloy is not hardenable by heat treatment. Strength above the annealed minima comes only from cold work.
Machining is more demanding than for Type 316L because of the high nitrogen and molybdenum content and the resulting work hardening. Rigid setups, sharp positive rake tooling, low speeds, heavy positive feeds and generous coolant are required.
Welding is normally carried out with an over-alloyed nickel-base filler such as ERNiCrMo-3 or ERNiCrMo-4, because autogenous or matching-composition welds suffer molybdenum segregation in the dendrite cores and lose pitting resistance.
Testing includes analysis to ASTM E1473, tensile testing to ASTM E8 / E8M and pitting resistance testing to ASTM G48.
Chemical Composition for Stainless Steel AL6XN Round Bar
Element
Symbol
Min
Max
Unit
Nickel
Ni
23.50
25.50
%
Chromium
Cr
20.0
22.0
%
Molybdenum
Mo
6.00
7.00
%
Nitrogen
N
0.18
0.25
%
Carbon
C
-
0.030
%
Manganese
Mn
-
2.00
%
Silicon
Si
-
1.00
%
Phosphorus
P
-
0.040
%
Sulfur
S
-
0.030
%
Copper
Cu
-
0.75
%
Iron
Fe
Balance
Balance
%
Chemical Composition
View the chemical composition and applicable material limits for AL-6XN Round Bar
Molybdenum at 6.00-7.00% defines the alloy. Against pitting and crevice corrosion in chloride solutions it is worth roughly three times as much as chromium, and this level is what lifts the pitting resistance equivalent number above 45 against about 25 for Type 316L.
Nitrogen at 0.18-0.25% performs three roles. It contributes strongly to pitting resistance, weighted at a factor of 16 in the PREN calculation, it stabilises the austenitic structure so that the high molybdenum does not force ferrite or intermetallic formation, and it provides substantial solid solution strengthening, giving a yield strength roughly 50% above Type 316L.
Stress-corrosion cracking resistance comes from the nickel, at 23.50-25.50%. Standard austenitic stainless steels with 8-14% nickel crack readily in hot chlorides, whereas at around 24% nickel the alloy becomes highly resistant to this failure mode.
Chromium at 20.0-22.0% forms the passive film and provides the base level of corrosion resistance in oxidising media.
Carbon is capped at 0.030% to prevent chromium carbide precipitation at grain boundaries during welding, which would cause sensitisation and intergranular attack. Copper up to 0.75% assists resistance in reducing acids such as sulphuric. Phosphorus and sulphur are held low to protect hot workability and weldability, with iron making up the balance.
Mechanical Properties for Stainless Steel AL6XN Round Bar
Mechanical Property
Value
Unit
Tensile Strength
655 (minimum, solution annealed)
MPa
Yield Strength 0.2% Proof
310 (minimum, solution annealed)
MPa
Elongation in 50 mm
30 (minimum, solution annealed)
%
Reduction of Area
50 (minimum, solution annealed)
%
Hardness
No Brinell limit specified by ASTM A276 for this grade
HBW
Hardness
Approximately 90 - 100 in the solution annealed condition (typical)
HRB
Impact / Charpy V-Notch
Not mandatory under ASTM B691 unless specified
J
Modulus of Elasticity
195 (typical)
GPa
Mechanical Properties
Check the key mechanical properties and performance requirements of AL-6XN Round Bar
The values listed are the room-temperature minima required by ASTM B691 for AL6XN rod and bar in the solution annealed condition: 655 MPa minimum tensile strength, 310 MPa minimum 0.2% offset yield strength, 30% minimum elongation and 50% minimum reduction of area. The same values appear in ASTM A276 / A276M, which also lists UNS N08367. Testing follows ASTM E8 / E8M, with hardness to ASTM E18.
The yield strength of 310 MPa is the property that most distinguishes the alloy mechanically. It is approximately 50% higher than the 205 MPa typical of Type 316L, and it comes almost entirely from interstitial nitrogen in solid solution. In pressure applications this translates directly into thinner wall sections and reduced weight for the same design pressure.
The alloy is not hardenable by heat treatment. Solution annealing dissolves precipitates and restores maximum corrosion resistance and ductility, and any strength above the annealed minima comes from cold work. Cold-drawn bar therefore tests considerably higher in tensile and yield strength with reduced elongation, so the delivered condition should be stated on the order.
Toughness is high and holds down to cryogenic temperatures, since the fully austenitic structure has no ductile-to-brittle transition.
The most important practical caution is that any exposure between roughly 600 and 1000 deg C precipitates sigma, chi and Laves phases, which reduce both toughness and corrosion resistance. Welding heat input must be controlled and interpass temperature kept low.
Dimension / Sizes for Stainless Steel AL6XN Round Bar
Dimension / Size
Value
Unit
Diameter (available range)
6 - 250
mm
Standard Length
3 - 6
m
Custom Length
Cut to length on request
-
Diameter Tolerance
Per ASTM B691 or ASTM A484 / A484M as applicable
-
Length Tolerance
Per ASTM B691 or as agreed
-
Straightness Tolerance
As agreed at time of order
-
End Condition
Square cut, saw cut, chamfered or as ordered
-
Surface Finish
Hot-finished and pickled, peeled, rough turned, cold-drawn, ground, polished
-
Cut-to-Length Availability
Available
-
Dimensional Standard
ASTM B691 and ASTM A484 / A484M
-
Dimensions & Sizes
Explore available diameters, lengths, and dimensional requirements for AL-6XN Round Bar
Pricing for Stainless Steel AL6XN 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 AL6XN Round Bar?
What standard does AL6XN Round Bar comply with?
How does AL-6XN compare with Type 316L?
What is the PREN of AL-6XN and why does it matter?
What are the key mechanical properties of AL6XN?
Can AL6XN be welded?
Why must AL6XN be rapidly cooled after annealing?
What sizes and finishes are available?
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