Grade dossier
AL-6XN Alloy for Severe Chloride and Process Service
A low-carbon, high-nickel, 6% molybdenum superaustenitic alloy designed for severe chloride pitting, crevice-corrosion and stress-corrosion-cracking conditions.
Identity before substitution
Define the grade, product and condition together
A familiar grade name is not a complete purchase specification. Product form, controlling standard, dimensions, condition, finish, certification and service environment determine whether the delivered material is suitable.
Composition control
ASTM A240/A240M flat-product chemistry
Limits are not heat analysis targets
The table summarizes grade limits commonly used for plate, sheet and strip. Pipe, tube, bar, forgings and cast products can be governed by different specifications. Always place the product standard and edition on the purchase order.
| C | 0.030 max |
|---|---|
| Mn | 2.00 max |
| Si | 1.00 max |
| P | 0.040 max |
| S | 0.030 max |
| Cr | 20.00-22.00 |
| Ni | 23.50-25.50 |
| Mo | 6.00-7.00 |
| N | 0.18-0.25 |
| Cu | 0.75 max |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Tensile strength | 655 MPa min |
|---|---|
| 0.2% yield strength | 310 MPa min |
| Elongation | 30% min |
| Hardness | 30.5 HRC max reference |
Selection indicators
| Density | about 8.06 g/cm3 |
|---|---|
| Primary benefit | Chloride pitting, crevice and SCC resistance |
| Strength | Higher than conventional austenitic stainless steels |
| Design note | Use code data for N08367, not generic 6Mo values |
Values depend on product form, thickness, test orientation, condition and governing edition. Use the mill test certificate and the purchase specification for acceptance, not a web table alone.
Selection boundary
Where AL-6XN belongs and where to escalate
Grade selection is an environmental decision, not a popularity contest. Review the complete medium, temperature, geometry, fabrication, cleaning and inspection requirements.
Good reasons to evaluate it
Flue-gas desulfurization systems
Reverse-osmosis and desalination equipment
Seawater heat exchangers and offshore equipment
Chemical-process tanks and pipelines
Reasons to stop and review
Treating N08367 and N08926 as identical
Using trade name alone on an RFQ
Assuming immunity in stagnant crevices
Matching filler without weld-segregation review
Fabrication route
Protect properties through cutting, forming and welding
Name UNS N08367 and the product specification.
Use qualified over-alloyed filler and heat-input controls.
Solution treatment and cooling control intermetallic phases.
Specify corrosion testing when failure consequence is high.
Supply definition
Product form changes the applicable requirements
Do not send an RFQ that names only the grade. State form, governing standard, dimensions, tolerances, finish, edge or end condition, quantity, certification and inspection.
Plate and sheet under ASTM A240 or B688 as applicable
Pipe and tube under applicable A/B specifications
Bar, forgings, fittings and flanges
Fabricated FGD, desalination and chemical-process equipment
Certificate checkpoint
Request heat identity, chemical analysis, mechanical results and compliance to the exact product specification. Add PMI, corrosion testing or supplementary examination only when the application requires it.
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Interactive selection check
Test AL-6XN against the controlling question
Procurement FAQ
Questions to close before placing the order
Is AL-6XN stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can AL-6XN replace another grade?
Only after checking the governing standard, composition, mechanical properties, corrosion exposure, fabrication route and certification. A commercial name is not a substitution approval.
Does the table apply to every product form?
No. N08367, N08926 and S31254 are separate UNS compositions. Select and certify the exact alloy required.
What should a AL-6XN RFQ include?
Product form, standard and edition, UNS or EN designation, dimensions, tolerances, finish, quantity, service, fabrication, certificate and inspection requirements.
Sources, scope and RFQ
Use traceable grade data, then specify the actual product
ASTM A240/B688 and related product specifications for UNS N08367
Rolled Alloys AL-6XN official datasheet and data book
Outokumpu Ultra 6XN grade-family guidance
Applicable ASME code cases and project corrosion data