What is Alloy 120 Seamless Pipe
UNS N08120 is a solid-solution-strengthened heat-resistant alloy considered for elevated-temperature applications requiring a combination of strength and environmental resistance. Grade identification, manufacturing origin and the ordered product requirements must be confirmed through the supply documents.
It is listed with the other nickel and nickel-alloy pipes on the Nickel and Nickel Alloy Seamless Pipes page.
Product Specification and Delivery Condition
ASTM B407 includes UNS N08120 seamless pipe and tube. For a pipe enquiry, identify the required edition and delivery condition, including any applicable grain-size requirements. ASTM B163 is a condenser and heat-exchanger tube specification and should not be used as the default title of this pipe page.
Where the actual requirement is heat-exchanger tubing, the tube form, specification and dimensions must be reviewed separately. A historical URL containing “b163” does not change the specification agreed for the supplied product.
Product Specifications and Data
1. Equivalent Grade
Cross-reference for UNS N08120 across major international standards and trade names.
| Grade / Trade Name | UNS | GB/T | JIS | DIN / EN (W.Nr.) | GOST |
|---|---|---|---|---|---|
| Alloy HR-120 | N08120 | NS1502 | — | 2.4854 | — |
| Nicrofer 3725 Nb | N08120 | NS1502 | — | 2.4854 | — |
| Haynes HR-120 | N08120 | NS1502 | — | 2.4854 | — |
2. Chemical Composition
N08120 chemical composition per ASTM B622. All values shown as weight percentage (wt%).
| Grade | C | Mn | P | S | Si | Cr | Ni | Fe | Mo | W | Nb | Ti | Al | Co | B | N |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UNS N08120 | 0.02 – 0.10 | ≤ 1.5 | ≤ 0.040 | ≤ 0.030 | ≤ 1.0 | 23.0 – 27.0 | 35.0 – 39.0 | remainder | ≤ 2.50 | ≤ 2.50 | 0.4 – 0.9 | ≤ 0.20 | ≤ 0.40 | ≤ 3.0 | ≤ 0.010 | 0.15 – 0.30 |
The defining feature of this alloy is the combination of high chromium (25% nominal), iron balance in place of expensive nickel, and W + Nb additions that stabilise the matrix at elevated temperatures and resist creep.
3. Mechanical Properties
Minimum mechanical properties for N08120 seamless pipe in the annealed condition per ASTM B622.
| Condition | Tensile Strength (Min) | Yield Strength 0.2% Offset (Min) | Elongation in 50 mm (Min) | Hardness (Max) | PREN (calculated) | Service Temperature Range |
|---|---|---|---|---|---|---|
| Hot-finished annealed or cold-worked annealed (ASTM B407) | 90 ksi (621 MPa) | 40 ksi (276 MPa) | 30% | not an acceptance limit in ASTM B407 | not applicable — the alloy contains no molybdenum | -196 °C to +300 °C (cryogenic to moderate high-temp) |
High-Temperature Performance Assessment
Relevant selection factors include oxidation, carburization or sulfidation exposure, operating and upset temperatures, thermal cycling, applied stress and required life. Environmental resistance and creep performance must be assessed separately. An oxidation-test temperature is not a universal allowable pressure-service temperature.
Primary Applications
N08120 seamless pipe is used in the following services.
Petrochemical Ethylene Cracker Radiant Coil Tubes
Furnace tubes in steam cracking units that operate continuously above 900°C and require resistance to both oxidation and carburisation from hydrocarbon feed gases.
Direct-Fired Industrial Furnace Radiant Tubes and Retorts
Heat treatment and annealing furnaces in steel and non-ferrous metalworking plants where tube metal temperatures exceed 1000°C under oxidising atmospheres.
Municipal and Hazardous Waste Incineration Superheater Tubes
High-temperature sections of waste-to-energy boilers where flue gases contain sulphur, chlorides, and heavy metal compounds that attack conventional stainless grades.
Reformer and Syngas Furnace Transfer Line Components
Primary and secondary reformer outlet manifolds and crossover piping in ammonia and methanol plants, where process temperatures run between 850°C and 1050°C under reducing conditions.
Power Generation High-Temperature Combustion Air Preheater Tubes
Heat recovery systems in gas turbine combined cycle plants where preheater outlet temperatures push the limits of standard austenitic stainless pipe materials.
Frequently Asked Questions
Which standard should be stated for Alloy 120 seamless pipe?
ASTM B407 includes UNS N08120 seamless pipe and tube. Confirm the required edition and delivery condition against the project and mill documents.
Is ASTM B163 the same procurement basis as ASTM B407?
No. B163 addresses condenser and heat-exchanger tubes; B407 covers specified nickel-iron-chromium seamless pipe and tube products. Use the specification appropriate to the actual product and service requirements.
Is 1095°C or 1150°C a universal service limit?
No. Service limits depend on environmental exposure, stress, design life and the applicable code. No universal pressure-service rating is stated on this page.
Does the grade name prove that the pipe was made by Haynes?
No. Manufacturer and product origin require traceable supply documents. Brand references must not imply an unverified source or authorization.
Technical References
Specification scope: ASTM B407. Grade background: Haynes International HR-120 alloy information. Trade names identify their respective owners and do not establish the origin of the quoted product.
Specification Control and Dimensions
The quotation and purchase order must identify the material grade, product specification and edition, delivery condition, dimensions and acceptance requirements. Chemical analysis, mechanical test results and dimensional inspection must be assessed against the agreed requirements for the supplied heat and product form.
Available dimensions are confirmed for the requested grade, outside diameter, wall thickness, length and delivery condition. Catalogue dimensions are not a guarantee that every size combination is available or held in stock. Dimensional tolerances, straightness, wall basis and cut-length tolerances are confirmed against the ordered specification.
Inspection and Traceability
State the inspection document type and any supplementary inspection in the enquiry. The agreed documentation should link the supplied material and heat marking to the material test results. Hydrostatic testing, nondestructive examination and supplementary tests are governed by the product specification and purchase order; test methods, coverage and acceptance criteria must be stated rather than assumed.
PMI can support alloy identification but does not replace the full chemical analysis or the material test certificate. Where carbon content distinguishes the ordered grade, use a chemical analysis method capable of measuring carbon. Specify any EN 10204 3.1 or 3.2 documentation and third-party witnessing before order confirmation; availability and scope are subject to agreement.
Design and Service Assessment
Seamless construction means the product has no longitudinal weld seam. It does not establish a universal pressure rating or corrosion guarantee. Design pressure, temperature and service life depend on the applicable code, dimensions, allowable stress, corrosion allowance, joint details and operating conditions. Typical material data must not be used as design allowable stresses.
Request a Quotation for Pipe
Send the grade and UNS designation; product specification and edition; NPS and schedule with the applicable dimensional standard, or actual OD and wall thickness; quantity; length; delivery condition; end finish; required inspection documents; and delivery destination. Include the operating medium, concentration, temperature and pressure when service suitability needs assessment. State the required delivery date so supply options can be reviewed.
Supplier Information
Wenzhou Xinzhe Tech Co., Ltd. is a China-based stockist and supplier of seamless stainless steel, duplex, super duplex, and nickel alloy pipes and tubes. Supply scope, specification, inspection documents and delivery terms are confirmed in the quotation.
