Standard and edition
Confirm the controlling document; a grade name or cross-reference alone is not a complete acceptance specification.
Superaustenitic Stainless Steel
AL6XN Round Bar — UNS N08367
AL6XN Round Bar is a high-molybdenum superaustenitic stainless steel bar, identified as UNS N08367, developed for demanding chloride-containing and corrosive environments.
Its chromium, nickel, molybdenum and nitrogen content supports resistance to pitting, crevice corrosion and chloride-related stress corrosion cracking. The material is used for machined components in marine, chemical processing and fluid-handling equipment.
For an enquiry, specify the ASTM product standard, diameter, length, finish, quantity, inspection requirements and delivery location.
At a glance
AL6XN Round Bar quick facts
- Product
- AL6XN Round Bar
- Material category
- Superaustenitic stainless steel
- Product reference
- AL6XN Round Bar
- Standards and designations referenced
- UNS N08367; ASTM B691 (bar and rod)
- Enquiry details
- Grade, dimensions and supply condition
Confirm the applicable specification and availability for your required size and condition.
Material overview
What Is AL6XN Round Bar?
AL6XN Round Bar is a solid, cylindrical form of AL-6XN (UNS N08367), a superaustenitic stainless steel containing approximately 6% molybdenum. It is used where conventional stainless steel may not provide enough resistance to chloride pitting and crevice corrosion. Its nickel and nitrogen additions also support a stable austenitic structure and useful mechanical strength.
Compared with general-purpose stainless steel round bars, AL6XN is selected for more demanding corrosion conditions. Engineers may also assess duplex stainless steel round bars or super duplex round bars, depending on the temperature, design strength and fluid chemistry. Materials are not automatically interchangeable: selection should follow the engineering specification.
Buyer selection guide
How to Select AL6XN Round Bar
Choose AL6XN according to the service medium, chloride exposure, operating temperature and required mechanical performance. The alloy designation alone does not confirm compliance with a particular purchase specification.
Confirm the gradeSpecify AL6XN / UNS N08367, and ask for heat traceability.
Identify the bar standardState ASTM B691 and the required edition, unless the design calls for a different governing specification.
Set dimensions and conditionProvide diameter, cut length, tolerances, solution-annealed condition where required, and finish.
Define inspectionRequest the material test certificate, dimensional inspection, PMI and any application-specific tests.
Common applications
Where Is AL6XN Round Bar Used?
AL6XN is chosen for components exposed to aggressive chloride-bearing liquids and other corrosive process media. Suitability still depends on concentration, temperature, design details and fabrication quality.
- Seawater handling: machined pump parts, shafts and components for desalination and cooling systems.
- Chemical processing: valve parts, fastener stock and equipment components exposed to corrosive solutions.
- Heat exchangers: associated machined parts in corrosion-sensitive heat-transfer equipment.
- Food and pharmaceutical processing: components where corrosion resistance and appropriate cleaning compatibility are required.
- Power and industrial processing: components used in chloride-bearing process and water systems.
When comparing materials for an application, review the relevant inspection and quality documentation requirements before procurement.
Specifications
AL6XN Round Bar Standards and Supply Details
AL6XN is often ordered as bar or rod under ASTM B691. Check the edition and exact acceptance requirements listed on the purchase order. The form, surface finish and available diameter must be confirmed for each enquiry.
| Item | Technical information |
|---|---|
| Alloy designation | AL-6XN / UNS N08367 |
| Alloy family | 6Mo superaustenitic stainless steel |
| Bar and rod standard | ASTM B691 (verify edition and product requirements) |
| Typical supply condition | Solution annealed; confirm exact order condition |
| Forms to enquire about | Round bar; other bar profiles subject to confirmation |
| Sizes and lengths | Specify diameter, tolerance, cut length and quantity; availability on request |
| Documentation | Material test certificate, heat traceability and specified inspections |
For machined parts, specify the required round bar diameter and finished-component allowance. Other profiles such as hex bar may be considered only if the required AL6XN form is available.
Chemical composition
AL6XN (UNS N08367) Chemical Composition
Published AL-6XN alloy composition ranges are shown below as percentages by weight. Actual batch chemistry is verified using the material test certificate and applicable specification.
| Element | Range or limit (wt. %) |
|---|---|
| Chromium (Cr) | 20.0–22.0 |
| Nickel (Ni) | 23.5–25.5 |
| Molybdenum (Mo) | 6.0–7.0 |
| Nitrogen (N) | 0.18–0.25 |
| Carbon (C) | 0.030 max |
| Manganese (Mn) | 2.00 max |
| Silicon (Si) | 1.00 max |
| Phosphorus (P) | 0.040 max |
| Sulfur (S) | 0.030 max |
| Copper (Cu) | 0.75 max |
| Iron (Fe) | Balance |
Molybdenum, chromium and nitrogen are important to the alloy's resistance to localized corrosion in chloride-containing environments. Values above describe alloy limits, not a substitute for heat-specific certification.
Mechanical properties
Mechanical and Physical Properties of AL6XN Round Bar
The following published minimum values are general reference properties for AL-6XN alloy. Confirm applicability to the purchased bar diameter, condition and ASTM B691 edition before specifying design values.
| Property | Published reference value |
|---|---|
| Tensile strength | 655 MPa (95 ksi) minimum |
| 0.2% offset yield strength | 310 MPa (45 ksi) minimum |
| Elongation | 30% minimum |
| Density | Approximately 8.06 g/cm³ |
| Hardness | 100 HRB maximum (published reference) |
Strength, ductility and inspection criteria vary with product form and condition. Review the supplied test certificate rather than treating a reference table as an unconditional guarantee.
Technical considerations
What to verify before specifying AL6XN Round Bar
Product condition
Check that property values apply to the required diameter, heat treatment, test direction and temperature.
Dimensions and finish
State tolerances, straightness, length, surface finish, machining allowance, and end condition where required.
Evidence and traceability
Define inspection, test reports, marking, heat identification, third-party requirements, and destination documentation.
Material designations
AL6XN Designations and Grade Identification
For ordering, identify the exact UNS grade. Some international 6Mo alloys are similar but may have different chemistry limits and approval requirements; they should not be described as automatically equivalent.
| Designation | Details |
|---|---|
| Commercial alloy name | AL-6XN |
| UNS | N08367 |
| ASTM bar reference | ASTM B691 |
| Comparable 6Mo grades | EN 1.4529 / UNS N08926 and SUS 3126 may be considered for comparison, not assumed as direct equivalents |
Any substitution requires confirmation against the engineering drawing, corrosion requirements, chemical composition and mechanical acceptance criteria.
Fabrication and verification
Important Considerations for AL6XN Round Bar
Machining and Fabrication
AL6XN is a highly alloyed austenitic material that can work harden during machining. Use suitable cutting tools, feeds and cooling practices for the specified bar size and condition. For fabricated assemblies, follow a qualified procedure for the required corrosion service.
Corrosion Resistance Is Service-Dependent
The alloy is particularly useful where chloride pitting and crevice corrosion are concerns. Local corrosion, stress corrosion cracking and galvanic effects still depend on actual environment, temperature and component design. Do not assume any alloy is universally corrosion-proof.
Inspection and Traceability
Where specified, obtain test certificates identifying heat number, chemistry, mechanical properties and applicable standard. Consult the quality assurance information or send an enquiry describing your inspection requirements.
Product questions
AL6XN Round Bar FAQs
What is AL6XN Round Bar?
It is a round bar made from AL-6XN, a high-molybdenum superaustenitic stainless steel designated UNS N08367. It is used for machined components in demanding corrosion environments.
What standard covers AL6XN round bar?
ASTM B691 is a common bar and rod specification for UNS N08367. Confirm the applicable edition and purchase requirements.
Why is AL6XN used in seawater and chloride environments?
Its chromium, molybdenum and nitrogen content supports resistance to localized corrosion, including pitting and crevice corrosion. Performance still depends on conditions of service.
What is the difference between AL6XN and 316L stainless steel?
AL6XN contains considerably more molybdenum and nickel, giving it higher localized-corrosion resistance in many chloride-bearing environments. Material selection should also consider cost, fabrication and design requirements.
Is AL6XN the same as EN 1.4529?
Both belong to the 6Mo superaustenitic stainless steel family, but the designations should not be assumed identical. Check chemistry and applicable specifications before substitution.
What details are needed for an AL6XN round bar quotation?
Provide UNS N08367, governing standard, diameter, length, quantity, required condition, tolerance, inspection certificates and delivery destination.