Z6NCTDV25-15B forging parts (A286 / UNS S66286 / 1.4980)

What forged products are available in Z6NCTDV25-15B?

Jiangyin Jiangnan Metal produces Z6NCTDV25-15B through three routes, chosen by geometry and order volume. Open-die forging on 25 MN and 40 MN hydraulic presses covers shafts, blocks, hollow bars and large discs. Seamless ring rolling on radial-axial mills produces rings from 200 mm to 2,500 mm outside diameter, the usual route for turbine casing rings, spacer rings and rolled-ring blanks. Upset forging handles short, large-cross-section discs, hubs and die blocks.

A286 work-hardens quickly and machines slowly, at roughly a quarter of the metal-removal rate of a free-machining stainless. Near-net-shape forging therefore pays back faster on this grade than it does on plain stainless. Profiling the die to the finished contour typically removes 30–50 % of the machining stock, and on aluminium-extrusion tooling that saving commonly exceeds the die cost on the first order.

• Seamless rolled rings
• Contoured & T-section rings
• Forged discs & blanks
• Forged shafts & spindles
• Extrusion dies & die inserts
• Extrusion mandrels & stems
• Extrusion liners & liner holders
• Die holders & pressure pads
• Sleeves, bushings & hollow bars
• Forged blocks & flange blanks
• Valve bodies, stems & seat rings
• Round / square / flat / hex bars
• Turbine & compressor spacers
• Fastener & bolting stock
• Custom near-net forgings

What is Z6NCTDV25-15B (A286 / UNS S66286)?

Z6NCTDV25-15B is a precipitation-hardening austenitic stainless steel, classified in most references as an iron-based superalloy, containing 24–27 % nickel and 13.5–16 % chromium, strengthened by gamma-prime Ni₃(Ti, Al) precipitates formed during ageing at about 720 °C. The French AFNOR name describes the chemistry directly, which is why the designation looks unfamiliar to engineers used to UNS numbers:

The same grade appears on French and Italian drawings as Z6NCTDV25.15, Z5NCTDV25-15 and Z5NCTDV26-15B. All describe UNS S66286 chemistry; the differences are editorial, not metallurgical.

Composition features that govern service behaviour

For a buyer, the practical consequence is that Z6NCTDV25-15B behaves as a heat-treatable superalloy rather than as an ordinary stainless steel. It must be solution treated and aged after forging, its properties are set by that cycle rather than by the forging operation, and it should be ordered with the heat-treatment condition stated explicitly.

Typical service: high-temperature bolting for steam and gas turbines and pressure-vessel flanges (ASTM A453 Grade 660); gas-turbine discs, spacers, casings and frames; turbocharger wheels, shafts and housings; aluminium-extrusion dies, mandrels, stems and liners; automotive engine fasteners, exhaust and manifold components; non-magnetic oilfield and downhole hardware; and cryogenic equipment where toughness must survive to −196 °C.

What is Z6NCTDV25-15B equivalent to?

Engineers reach this alloy through at least a dozen different names on drawings. They all describe the same chemistry, and Jiangyin Jiangnan Metal Co., Ltd. accepts purchase orders under any of them, supplying UNS S66286 material cross-certified on a single mill test certificate.

Related but not interchangeable: Incoloy 901 and Nimonic 901 are higher-nickel developments of the same gamma-prime family with higher temperature capability; Inconel 706 and Inconel 718 are niobium-strengthened nickel-base alloys. Substituting one for another changes strength, temperature capability and price, and must be agreed with the end user in writing.

What is the chemical composition of Z6NCTDV25-15B / UNS S66286?

The limits below are the UNS S66286 requirements common to ASTM A453 Grade 660, ASTM A638 Grade 660 and the AMS specifications. Every heat we forge is verified twice: ladle analysis from the melt source, then product analysis on the forged part by optical emission spectrometry. Both results appear on the certificate.

Composition per UNS S66286 as adopted in ASTM A453 / A638 Grade 660. Individual AMS specifications and customer specifications vary slightly in the residual limits. Where your drawing calls a specific AMS number, quote it on the enquiry and the mill certificate will be issued against that document. The mill test certificate for the delivered heat always governs.

What are the mechanical properties of Z6NCTDV25-15B?

The values below are the room-temperature minima we certify for forgings supplied in the solution-treated and aged condition. Results for every forging are reported on the EN 10204 certificate, tested per ASTM E8/E8M on coupons taken from the same heat and heat-treatment batch.

ASTM A453 Grade 660 divides the same chemistry into four tensile classes distinguished by the solution and ageing cycle applied. All four share the 895 MPa tensile minimum; the classes differ in yield strength and in the stress-rupture testing required.

Reduction of area 18 % minimum for all classes. Class-specific solution and ageing cycles, hardness limits and stress-rupture requirements are defined in the edition of ASTM A453 in force at the contract date. Always state the class on the purchase order, because "A453 Grade 660" on its own does not define the properties.

Design implications

At 585–725 MPa yield, Z6NCTDV25-15B sits well above austenitic stainless steels and well below Inconel 706 or Inconel 718. It is chosen when the design needs strength and temperature capability and a thermal expansion coefficient close to that of austenitic stainless, so that a bolted joint of A286 studs in a stainless flange does not lose preload as the assembly heats. Where the design needs more than about 725 MPa yield at temperature, the move is to a nickel-base grade. Tell us the required strength level on the enquiry and our engineering team will confirm which grade meets both requirements.

What are the physical properties of Z6NCTDV25-15B?

Rows marked typical or indicative are representative values for the UNS S66286 family and are given for design guidance only. Where a physical property is contractually significant, thermal expansion in a bolted flange stack-up being the usual case, request that the value be verified for the specific heat before ordering.

How is Z6NCTDV25-15B forged and heat treated?

Z6NCTDV25-15B is forged from about 1120 °C (2050 °F) and finished above roughly 925 °C (1700 °F). The working window is narrow. Below the finish temperature the alloy work-hardens sharply, press loads climb and surface cracking risk rises. Soaking too hot coarsens the grain and costs stress-rupture life. Reheats between passes are normal and are recorded on the furnace chart.

The forging operation does not set the properties. Strength comes entirely from the post-forge heat treatment, in two stages:

1. Solution treatment. Typically 900 °C (1650 °F) where room-temperature strength and ductility govern, or 980 °C (1800 °F) where creep and stress-rupture life govern, held about one hour per 25 mm of ruling section, then oil quenched. The higher solution temperature dissolves more titanium and produces a coarser grain, which is better under creep; the lower temperature keeps the grain fine, which is better for tensile ductility and notch toughness.
2. Ageing. 720 °C (1325 °F) for 16 hours, air cool. This precipitates the gamma-prime Ni₃(Ti, Al) that carries the load. The 16-hour hold is a specification requirement, not an approximation. Shorter ages leave the alloy under-strength; longer ages at higher temperature over-age it and drop the yield.

1. Raw material EAF+VOD+ESR billet, or VIM+VAR / VIM+ESR where an AMS specification applies. Heat number recorded, ladle chemistry verified on receipt.
2. Heating Computer-controlled gas furnace to 1120 °C. Soak to through-temperature; low-sulfur atmosphere, since sulfur embrittles titanium-bearing alloys.
3. Forging Open-die press or radial-axial ring mill. Forging ratio 4:1 or better, incremental reduction, finish above 925 °C, reheats as needed.
4. Solution treatment 900 °C or 980 °C to the specified class, about 1 h per 25 mm, oil quench. Chart recorded per batch.
5. Ageing 720 °C for 16 h, air cool. Load thermocouples on the part, not only in the furnace.
6. Rough machine Turning or boring to the agreed stock allowance. Carbide tooling, positive rake, rigid setup, no dwell.
7. Testing Tensile, hardness, impact, UT and PT; stress rupture and grain size where specified.
8. Certification EN 10204 3.1 or 3.2, PMI, marking, packing for sea freight.

How does Z6NCTDV25-15B behave at temperature and in corrosive service?

Where is Z6NCTDV25-15B used?

The applications below are the ones we forge most often in this grade. Every part is made to the customer's drawing.

Forged in the same grades: forging rings, forged disks, forged cylinders, forging round bars, forging pipes and forging pieces.

Z6NCTDV25-15B vs Inconel 718, 17-4 PH, Waspaloy and 316: which should you specify?

Buyers of A286 usually want to know where a cheaper grade would serve and where a stronger one is required. The table compares the alternatives we most often quote against it.

Cost multipliers are indicative ratios of forged material cost per kilogram against 316, based on our own 2026 purchasing, and move with the LME nickel, ferro-molybdenum and titanium indices. Ask for a current spot indication before budgeting.

Is Z6NCTDV25-15B acceptable for sour service under NACE MR0175 / ISO 15156?

UNS S66286 appears in NACE MR0175 / ISO 15156-3 as an acceptable precipitation-hardening alloy for defined H₂S-containing service, with a maximum hardness of 35 HRC. The datasheet line that many buyers quote, "NACE MR0175 limits the supply hardness to 35 HRC max", is correct but incomplete.

The listing does not mean that any A286 part is automatically acceptable. The qualified envelope in the standard is defined by H₂S partial pressure, chloride concentration, in-situ pH, temperature, elemental sulfur presence, and the delivery condition and hardness of the material. Before ordering:

1. State the sour-service requirement on the enquiry, quoting NACE MR0175 / ISO 15156-3 and the edition in force at the contract date.
2. Give the environmental data (H₂S partial pressure, chloride, pH, maximum temperature) so the applicable table in the standard can be checked against your duty.
3. Specify the delivery condition: solution treated and aged, and to which ASTM A453 class or AMS number.
4. Specify the maximum hardness and where it is to be measured. For forgings we map hardness at multiple locations including mid-wall of heavy sections, and report every reading on the certificate.

How do you weld and machine Z6NCTDV25-15B?

Welding

A286 is a gamma-prime-strengthened alloy, and alloys of this type are among the harder ones to weld. Two failure modes dominate: heat-affected-zone liquation cracking during welding, and strain-age cracking during the post-weld heat treatment as the gamma-prime re-precipitates while residual stress is still present. The main precautions are:

• Weld in the solution-treated condition wherever the sequence allows, then solution treat and age the completed fabrication. Welding fully aged material is possible but far more likely to crack.
• GTAW is the usual process. Matching filler is A286 wire to AMS 5804; where matching strength is not required, a nickel-alloy filler such as ERNiCrMo-3 (Alloy 625) gives a more forgiving weld.
• Keep heat input low, interpass temperature low, use stringer beads with minimum weave, and restrain the joint as little as the fit-up allows.
• Clean the joint thoroughly. Sulfur, lead and other low-melting contamination from marker pens, cutting fluid or grease causes cracking in every titanium-bearing high-nickel alloy.
• For pressure-retaining or rotating parts, qualify the procedure on the actual section thickness. Results from a thin-plate coupon should not be extrapolated to heavy sections.

Machining

Z6NCTDV25-15B machines like an austenitic superalloy. It work-hardens rapidly, it is gummy, and it holds heat at the cutting edge. Rough machine in the solution-treated condition where the drawing tolerance allows, then finish after ageing, allowing for the small dimensional change that ageing produces. Use rigid setups and sharp positive-rake carbide tooling, keep a heavy positive feed so the tool cuts under the work-hardened layer instead of rubbing, run turning speeds in the region of 15–25 m/min with carbide, and flood with coolant. Never dwell, because a stopped tool glazes the surface and the next pass has to cut through it. Where a bore above roughly Ø100 mm is needed, ordering a trepanned or forged-hollow blank rather than a solid forging saves both material and drilling time.

Non-destructive examination

The alloy is austenitic and non-magnetic, so magnetic-particle inspection does not apply. Surface examination is by liquid penetrant per ASTM E165 / E1417. Volumetric examination is by ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388 as specified on the order, noting that coarse-grained forgings attenuate ultrasound and may need a lower test frequency and a calibration block made from the same grade and heat-treatment condition.

Production capability: Z6NCTDV25-15B forging manufacturer

Jiangyin Jiangnan Metal Co., Ltd. has forged open-die parts and seamless rolled rings at Zhouzhuang Town, Jiangyin since 2008, exporting to more than 40 countries. Titanium-bearing grades including Z6NCTDV25-15B are run on dedicated tooling and in clean, low-sulfur furnace atmospheres to avoid contamination from carbon-steel production.

Max ring OD

2,500mm

Max disc Ø

1,800mm

Max shaft length

8m

Max single piece

8,000kg

Bar Ø range

25–500mm

Largest press

40MN

Typical lead time

8–10weeks

Quotation

24hours

Machining is performed in-house to rough or finished dimensions. Where a customer-nominated inspector requires witness points, these are scheduled at solution treatment, ageing, mechanical testing and final release.

What testing and certification is supplied with Z6NCTDV25-15B forgings?

Standard supply for every Z6NCTDV25-15B forging is an EN 10204 3.1 mill test certificate issued by our own quality department, listing heat number, ladle and product chemistry, the solution and ageing cycles actually used, tensile, hardness and impact results, dimensional report and NDE results. EN 10204 3.2 certificates witnessed by DNV, BV, Lloyd's Register, ABS or TÜV are available on request.

Non-conformance handling. Any out-of-specification finding triggers a written report within 24 hours. You receive the finding and the proposed disposition (re-age, re-solution treat, rework, regrade or scrap) before anything is done to the part. Records are retained for ten years so that a claim can be traced back to the melt.

How to specify a Z6NCTDV25-15B forging order

An enquiry that contains the seven items below can be quoted the same day. Missing information adds an email round-trip and normally a day to the response.

1. Grade wording Write UNS S66286, adding Z6NCTDV25-15B and W.Nr. 1.4980 for European projects. Avoid ordering by a trade name alone.
2. Product specification ASTM A453 Grade 660 with the class, ASTM A638 Grade 660, an AMS number, EN 10269, or your own company specification.
3. Drawing 2D drawing or 3D model with tolerances, surface finish and machining datum. State rough or finish machined.
4. Delivery condition Solution treated at 900 or 980 °C, oil quenched, aged 720 °C × 16 h. Alternatively, name the ASTM A453 class and let the class define it.
5. Testing & NDE UT standard and acceptance class, PT class, impact temperature, stress rupture, hardness limit and where it is measured.
6. Certification EN 10204 3.1 or 3.2, inspection body if witnessed, NACE MR0175 statement if sour.
7. Commercial Quantity, required delivery date, Incoterm and destination port.

Drawing callout template

MATERIAL:      Z6NCTDV25-15B / UNS S66286 / W.Nr. 1.4980
               (X6NiCrTiMoVB25-15-2, alloy A286)
SPECIFICATION: ASTM A453 Grade 660 Class __   [or ASTM A638 Gr 660 / AMS 57__]
MELT ROUTE:    EAF + VOD + ESR   [VIM + VAR where AMS applies]
CONDITION:     Solution treated 980 C (or 900 C), 1 h per 25 mm, oil quench
               + age 720 C x 16 h, air cool
MECHANICAL:    UTS >= 895 MPa, YS 0.2% >= 585 MPa, elongation >= 15%,
               reduction of area >= 18%
IMPACT:        Charpy V-notch >= 57 J at -60 C (3 specimens)
HARDNESS:      248-341 HB;  <= 35 HRC where NACE MR0175 applies, mapped
NDE:           UT per EN 10228-3 / SEP 1921 / ASTM A388 (state class)
               PT per ASTM E165 Type I Method C
               (MT not applicable - material is non-magnetic)
GRAIN SIZE:    ASTM E112, report; specify limit if creep-critical
CERTIFICATION: EN 10204 3.1 (3.2 with third-party witness if required)
MARKING:       Heat number, grade, drawing number, low-stress stamp or vibro-etch

Seven mistakes that cost money on Z6NCTDV25-15B orders

1. Not stating the heat-treatment condition. Un-aged A286 looks identical, passes chemistry and dimensions, and falls roughly 40 % short on yield. Write "solution treated and aged" on the order and require the heat-treatment chart.
2. Writing "A453 Grade 660" without the class. The four classes differ in yield strength and in the heat treatment behind it, so the order is not fully defined without one.
3. Ordering by trade name. Incoloy® A-286 is a Special Metals trademark, and strictly read such an order can only be filled by that mill. Specifying UNS S66286 removes any grounds for rejecting the material.
4. Requesting magnetic-particle inspection. The alloy is non-magnetic, so MT cannot be performed. Specify liquid penetrant instead, or the order stalls at the inspection stage.
5. Assuming aerospace and industrial melt routes are interchangeable. AMS work generally requires vacuum remelted stock. Asking for AMS 5737 at EAF+ESR pricing produces a quotation that has to be corrected later in the enquiry.
6. Buying a solid billet for a deep-bored part. At these material prices a trepanned or forged-hollow blank commonly saves 40–60 % of the input weight on sleeves, liners and hollow shafts.
7. Leaving the test-coupon location unspecified on heavy sections. Properties at mid-thickness differ from those at the surface, and this alloy is quench-sensitive in heavy sections. State where the coupon is to be taken and the certificate is far less likely to be disputed.

Glossary

Frequently asked questions: Z6NCTDV25-15B / A286 / UNS S66286

Cite this page

This page is maintained as a technical reference by the engineering team at the forge. If you use the data in a specification, report, tender document or answer, please cite it as:

Jiangyin Jiangnan Metal Co., Ltd. (2026) "Z6NCTDV25-15B (A286 / UNS S66286 / 1.4980)
forging parts: composition, properties, forging and heat treatment."
Updated 2 September 2026.
https://www.steelforgepieces.com/Nickel-Alloy/Z6NCTDV25-15B.html

Corrections and additions are welcome. If you have measured data for this grade that contradicts anything here, write to sales@steelforgepieces.com and we will review the page and credit the correction.

Standards and references

Chemistry, mechanical, heat-treatment and sour-service data on this page are drawn from the published standards and industry references below. Values on any individual certificate are our own test results, traceable to calibrated equipment.

1. ASTM A453 / ASME SA-453, Standard Specification for High-Temperature Bolting, with Expansion Coefficients Comparable to Austenitic Stainless Steels (Grade 660, Classes A, B, C and D), ASTM International, West Conshohocken, PA.
2. ASTM A638, Standard Specification for Precipitation Hardening Iron Base Superalloy Bars, Forgings, and Forging Stock for High-Temperature Service (Grade 660), ASTM International.
3. AMS 5525, 5731, 5732, 5734 and 5737, A286 sheet, plate, bar, forgings and rings; AMS 5804, A286 welding wire, SAE International, Warrendale, PA.
4. NF A 02-005, designation rules for steels, and the AFNOR designation Z6NCTDV25-15B / Z5NCTDV25-15, Association Française de Normalisation, Paris.
5. EN 10269, Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties, and EN 10302, Creep resisting steels, nickel and cobalt alloys, CEN, Brussels.
6. EN 10228-3, Non-destructive testing of steel forgings, ultrasonic testing of ferritic or martensitic steel forgings; SEP 1921, ultrasonic testing acceptance classes; ASTM A388, ultrasonic examination of steel forgings.
7. ASTM E8/E8M, tension testing; ASTM E112, grain size; ASTM E165 / E1417, liquid penetrant testing; ASTM E381, macroetch testing; ASTM E139, creep and stress-rupture testing, ASTM International.
8. NACE MR0175 / ISO 15156-3, Petroleum and natural gas industries, materials for use in H₂S-containing environments in oil and gas production, part 3: cracking-resistant CRAs and other alloys.
9. EN 10204, Metallic products, types of inspection documents, CEN, Brussels.
10. GB/T 14992 and the GH2132 (06Cr15Ni25Ti2MoAlVB) superalloy designation, Standardization Administration of China.
11. JIS G 4311, heat-resisting steel bars (SUH 660), Japanese Standards Association.
12. ASM Handbook, Volume 1, Properties and Selection: Irons, Steels, and High-Performance Alloys; Volume 4, Heat Treating; Volume 14A, Metalworking: Bulk Forming, ASM International, Materials Park, OH.
13. Special Metals Corporation, INCOLOY® alloy A-286 product literature (UNS S66286 / W.Nr. 1.4980).

Standards are referenced without an edition number because editions change; for procurement, always cite the revision in force at the contract date. All trademarks belong to their respective owners.

Request a quotation for Z6NCTDV25-15B / UNS S66286 forgings

Other grades we forge

• Incoloy A-286
• Incoloy 901
• Nimonic 901
• Inconel 706
• Inconel 725
• Inconel X-750
• Inconel 625
• Waspaloy
• Nimonic 80A
• Nimonic 90
• Nimonic 263
• Rene 41
• Udimet 500
• Udimet 520
• Udimet 720
• MP35N
• MP159
• Multimet N155
• Haynes 25
• Haynes 188
• Haynes 230
• Hastelloy X
• Hastelloy C-276
• Incoloy 800H
• Incoloy 825
• Incoloy 925
• Incoloy 945
• NI-SPAN-C 902
• 17-4 PH
• 15-5 PH
• 17-7 PH
• PH13-8Mo
• AISI 330
• All nickel alloys