UNS N10665 Forgings: Hastelloy B-2, Alloy B2, W.Nr. 2.4617 Open-die forged rings, seamless rolled rings, flanges, bars, discs, shafts and tube sheets to ASTM B564

Q: What are the minimum mechanical properties of UNS N10665 forgings?

In the solution-annealed condition, ASTM B564 requires a minimum tensile strength of 110 ksi (760 MPa), a minimum 0.2 percent offset yield strength of 51 ksi (350 MPa) and a minimum elongation of 40 percent in 2 in. or 4D.

Q: Can UNS N10665 be age hardened?

No. UNS N10665 is a solid-solution-strengthened alloy and is not precipitation hardenable. The only heat treatment applied to forgings is solution annealing at about 1065 C (1950 F) followed by rapid quenching. Ageing is not only ineffective, it is harmful, because holding the alloy in the roughly 600 to 900 C range promotes Ni4Mo and other intermetallic precipitation that embrittles the material and reduces corrosion resistance.

Q: What is the forging temperature range for UNS N10665?

UNS N10665 is forged between approximately 1232 C and 982 C (2250 F to 1800 F). Work should stop before the metal falls below about 982 C, and the forging is then solution annealed at about 1065 C and rapidly quenched to restore a fully solutioned microstructure.

Q: What is the difference between Hastelloy B-2 and Hastelloy B-3?

Both are nickel-molybdenum alloys with about 28 percent molybdenum, but B-3 (UNS N10675) has a modified composition with a controlled chromium and iron addition that gives it much better thermal stability and far greater tolerance of the 600 to 900 C range and of oxidising contamination. B-2 (UNS N10665) remains the choice for clean, confirmed reducing hydrochloric acid service, while B-3 is preferred where the process can see thermal excursions or oxidising species such as ferric or cupric ions.

Summary

UNS N10665 is a solid-solution-strengthened nickel-molybdenum alloy containing 26.0 to 30.0 % molybdenum, with nickel as the balance and no deliberate chromium addition. It is sold under the trade name Hastelloy B-2 and is also designated Alloy B2, W.Nr. 2.4617, NiMo28 and NW0665. The alloy was developed for resistance to reducing acids, above all hydrochloric acid at every concentration up to the boiling point. It is used for pumps, valves, reactors and heat exchangers in hydrochloric, sulphuric, phosphoric and acetic acid service.

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China that manufactures UNS N10665 forged rings, seamless rolled rings, flanges, round bars, discs, shafts, sleeves, bushings and tube sheets to ASTM B564. Forgings are supplied solution annealed, ultrasonically tested to EN 10228-3 and certified to EN 10204 3.1 or 3.2. Send a drawing to sales@steelforgepieces.com for a quotation.

UNS: N10665
Werkstoff: 2.4617
Molybdenum: 26 to 30 %
Tensile R_m: 760 MPa min
Yield R_p0.2: 350 MPa min
Elongation: 40 % min
Density: 9.2 g/cm³
Condition: Sol. annealed

A note on the spelling “UNS N010665”. The designation is frequently written with an extra zero. The correct UNS number for this nickel-molybdenum alloy is N10665, with five digits after the letter N. Both spellings refer to the same material, and this page is kept at the historical URL so that existing links continue to work.

Designations and equivalent grades

UNS N10665 appears in drawings and purchase specifications under a large number of names. All of the following refer to the same nickel-molybdenum alloy, and Jiangyin Jiangnan Metal accepts enquiries against any of them.

Table 1. UNS N10665 designations and international equivalents
Designation system	Designation	Notes
UNS	N10665	Correct designation. Often mistyped as N010665 or NO10665.
Trade name	Hastelloy® B-2	Registered trade name of Haynes International.
Common name	Alloy B2, Alloy B-2, Nickel B2	Generic names used in procurement documents.
Werkstoff / EN	2.4617	Also listed historically as 2.4615.
DIN / ISO	NiMo28	ISO 6207, 6208, 9723, 9724, 9725.
JIS	NW0665	JIS H4551 to H4554.
Other trade names	Nimofer 6928, Nicrofer B 6928	European mill designations.
Welding consumables	ERNiMo-7 / ENiMo-7	AWS A5.14 wire, AWS A5.11 electrode.

Hastelloy® is a registered trademark of Haynes International, Inc. Jiangyin Jiangnan Metal Co., Ltd. is not affiliated with Haynes International; the name is used here only to identify the alloy specification.

Product specifications that cover UNS N10665

Table 2. Applicable ASTM and ASME product specifications
Standard	Product form	Relevance to forgings
ASTM B564 / ASME SB-564	Nickel alloy forgings	Primary specification for the forgings on this page.
ASTM B335 / ASME SB-335	Ni-Mo alloy rod and bar	Used for forged and rolled round bar.
ASTM B333 / ASME SB-333	Plate, sheet and strip	Reference for flat forged products.
ASTM B366 / ASME SB-366	Factory-made wrought fittings	Forged fittings and forged pipe components.
ASTM B622 / B619 / B626	Seamless and welded pipe and tube	Downstream piping matched to forged flanges.
ASTM B462	Forged or rolled flanges and fittings for high-temperature service	Alternative flange specification.
GB/T 15007	Corrosion-resistant alloy designations	Chinese national reference standard.

Chemical composition of UNS N10665

The composition below is the ASTM requirement for UNS N10665. The defining features are the very high molybdenum content and the near-absence of chromium, which together produce the resistance to reducing acids. Carbon and silicon are held far lower than in the original Alloy B, which is what suppresses knife-line attack in the weld heat-affected zone.

Table 3. UNS N10665 (Hastelloy B-2) chemical composition, weight %, per ASTM B564 and B335
LimitWT %	NiNICKEL	MoMOLYB.	FeIRON	CrCHROM.	CoCOBALT	MnMANG.	CCARBON	SiSILICON	PPHOS.	SSULPHUR
Minimum	Balance	26.0	–	–	–	–	–	–	–	–
Maximum	Balance	30.0	2.0	1.0	1.0	1.0	0.02	0.10	0.04	0.03

Nickel is the balance and is typically about 69 %. Iron is a maximum of 2.0 %; there is no minimum iron requirement for this grade. Values are the specification limits. The certified heat analysis is supplied with every order.

Correction to a widely copied error. Several online datasheets, including an earlier version of this page, list iron for N10665 as “2.0 minimum, 7.0 maximum”. That is wrong. ASTM specifies iron as 2.0 % maximum for N10665. The 1 to 3 % and 2 to 4 % iron ranges belong to Hastelloy B-3 (UNS N10675) and Hastelloy B-4 (UNS N10629) respectively.

Mechanical properties of UNS N10665 forgings

ASTM B564 specifies the following room-temperature minima for nickel-molybdenum alloy UNS N10665 forgings in the solution-annealed condition. The same minima apply to UNS N10675 (B-3) and UNS N10629 (B-4).

Table 4. Room-temperature mechanical requirements, solution annealed, per ASTM B564 Table 2
Property	Minimum (metric)	Minimum (imperial)	Test basis
Tensile strength R_m	760 MPa	110 ksi	ASTM E8 / E8M
Yield strength R_p0.2	350 MPa	51 ksi	0.2 % offset
Elongation A	40 %	40 %	In 50 mm or 4D
Reduction of area	Typically 50 %	Typically 50 %	Not mandated by B564; report on request
Hardness	Typically 100 HRB max	Typically 100 HRB max	Informative; agreed at enquiry
Grain size	ASTM No. 5 or coarser unless otherwise agreed		ASTM E112

For seamless pipe and tube to ASTM B622 the yield minimum drops to 45 ksi (310 MPa). The 51 ksi figure above is the forging requirement. Elevated-temperature allowable stresses are given in ASME BPVC Section II Part D.

Physical properties of UNS N10665

Table 5. Typical physical properties at room temperature unless stated
Property	Value (metric)	Value (imperial)
Density	9.2 g/cm³	0.333 lb/in³
Melting range	1330 to 1380 °C	2426 to 2516 °F
Modulus of elasticity in tension	217 GPa	31.5 × 10³ ksi
Thermal conductivity at 20 °C	approx. 11 W/m·K	approx. 6.4 Btu·ft/ft²·h·°F
Mean thermal expansion, 20 to 100 °C	approx. 10.3 µm/m·K	approx. 5.7 µin/in·°F
Specific heat at 20 °C	approx. 373 J/kg·K	approx. 0.089 Btu/lb·°F
Electrical resistivity at 20 °C	approx. 1.37 µΩ·m	approx. 825 Ω·circ mil/ft
Magnetic permeability	Non-magnetic in the solution-annealed condition

Physical properties are typical values for the alloy and are not specification requirements. Design should be based on the certified test results for the specific heat supplied.

Forging and heat treatment practice

UNS N10665 is a stiff, work-hardening alloy with a comparatively narrow hot-working window. Jiangyin Jiangnan Metal forges it on open-die hammers and hydraulic presses using the following practice.

Melting route

EAF melting with AOD or VOD refining, followed by electroslag remelting where the customer specification or section size calls for it. ESR improves ingot soundness and sulphur control.

Forging temperature

Heat to approximately 1232 °C (2250 °F) and finish above approximately 982 °C (1800 °F). Reheat rather than continue forging below the finishing temperature.

Solution annealing

Approximately 1065 °C (1950 °F), held for section thickness, followed by rapid water quenching. Slow cooling through 900 to 600 °C must be avoided.

Ring rolling

Seamless rolled rings are produced from upset and punched blanks, giving continuous circumferential grain flow and better ductility than a cut-and-welded ring.

UNS N10665 cannot be age hardened, and ageing must not be specified. It is a solid-solution-strengthened alloy: strength comes from molybdenum in solution, not from precipitates. Holding the alloy in the approximately 600 to 900 °C range promotes Ni₄Mo and other intermetallic phases that embrittle the forging and reduce its corrosion resistance. The only correct heat treatment is solution anneal plus rapid quench. Some older supplier datasheets describe a “solution and ageing” cycle for this grade. That instruction is incorrect and should not be carried into a purchase specification.

Welding and machining notes

Welding: GTAW/TIG or SMAW/MMA with matching ERNiMo-7 or ENiMo-7 consumables. The low carbon and silicon of B-2 allow it to be used in the as-welded condition in many services. A post-weld solution anneal is still preferred for severe HCl duty.
Interpass control: keep heat input and interpass temperature low to limit time in the precipitation range.
Machining: the alloy work hardens rapidly. Use rigid setups, positive rake, slower surface speeds and a heavy, uninterrupted feed so the tool cuts below the previously hardened layer.
Cleanliness: keep sulphur, phosphorus, lead and other low-melting-point contaminants off the surface before any heating operation.

Corrosion resistance and where UNS N10665 fits

The 26 to 30 % molybdenum content gives UNS N10665 its resistance to reducing media. In clean hydrochloric acid it resists all concentrations from dilute to concentrated, including at boiling temperature, which no stainless steel and no C-family nickel alloy can match. It is similarly effective in sulphuric acid across the reducing range, in phosphoric, acetic and formic acids, and in hydrogen chloride gas.

The limitation to check before specifying B-2. With essentially no chromium, UNS N10665 has no defence against oxidising species. Ferric ions (Fe³⁺), cupric ions (Cu²⁺), dissolved oxygen, nitric acid and nitrates raise corrosion rates sharply even at low concentration. If the process stream can be contaminated, or if the duty is mixed oxidising and reducing, specify Hastelloy C-276, C-22 or Alloy 59 instead. If the concern is thermal excursions rather than contamination, Hastelloy B-3 is the direct upgrade.

Table 6. Selecting between the B-family and C-family nickel alloys
Alloy	UNS	Mo / Cr, %	Best suited to
Hastelloy B	N10001	26-30 / –	Superseded original grade. Higher C and Si make it prone to knife-line attack. Not recommended for new build.
Hastelloy B-2 (this page)	N10665	26-30 / 1.0 max	Clean, confirmed reducing HCl and H₂SO₄ service with no oxidising contamination and no long dwell at 600 to 900 °C.
Hastelloy B-3	N10675	27-32 / 1-3	Same acid duty as B-2 but with far better thermal stability and tolerance of upset conditions. The usual modern replacement for B-2.
Hastelloy B-4	N10629	27-30 / ~1.5	European variant with improved fabricability over B-2.
Hastelloy C-276	N10276	15-17 / 14.5-16.5	Mixed oxidising and reducing duty, chlorides, pitting and crevice corrosion. The default choice when contamination is possible.
Hastelloy C-22	N06022	12.5-14.5 / 20-22.5	Strongly oxidising conditions, wet chlorine, ferric and cupric chlorides.

UNS N10665 forged product forms we manufacture

Jiangyin Jiangnan Metal Co., Ltd. produces UNS N10665 forgings to drawing. Because the forgings are open-die and ring-rolled rather than closed-die, there is no tooling cost and single pieces and small batches are economic.

Table 7. Product forms, typical size envelope and applicable specification
Forged product	Typical size range	Specification
Forged rings and seamless rolled rings	OD 200 to 3000 mm, wall 20 to 400 mm	ASTM B564
Forged flanges: WN, SO, BL, LJ, orifice	1/2″ to 60″, Class 150 to 2500	ASTM B564, ASME B16.5, B16.47
Forged round bars	Ø 20 to 800 mm	ASTM B335 / B564
Forged discs and disks	Ø 100 to 2500 mm	ASTM B564
Forged shafts, spindles, eccentric shafts	Ø 60 to 900 mm, up to 8000 mm long	ASTM B564
Forged sleeves and bushings	OD 100 to 1500 mm	ASTM B564
Forged tube sheets	Ø up to 3000 mm, thickness to 500 mm	ASTM B564 / B333
Forged valve bodies, seat rings, stems, blocks	To drawing	ASTM B564 / B366
Forged pipes, tubes, nozzles	Hollow forged, OD 100 to 1200 mm	ASTM B564 / B366
Forged blocks and custom open-die shapes	To drawing, single pieces accepted	ASTM B564

Delivery condition: as-forged, rough machined, or finish machined to drawing. Related forged components in other grades: forged bushings, forged valve seat rings.

Where UNS N10665 forgings are used

The alloy is specified wherever a component sees strong reducing acid and cannot tolerate the corrosion rates of stainless steel. Typical forged components by industry:

Chemical and petrochemical processing

Hydrochloric acid synthesis reactors, absorbers and transfer systems: forged nozzles, flanges and tube sheets.
Sulphuric acid dilution, storage and handling in the reducing range: forged shafts and rings for pumps.
Acetic and formic acid reactors, and wet-process phosphoric acid evaporators: forged rings and discs.
Columns, towers, tanks, silos, preheaters and process modules: forged flanges and rolled rings.

Rotating and pressure equipment

Chemical process pumps and plunger pumps: forged shafts, sleeves and seal rings.
Shell-and-tube heat exchangers and air receivers: forged tube sheets, forged flanges and hollow forgings.
Gear boxes, turbines and compressors in acid service: forged gears, spindles and bars.

Valves and flow control

Ball, gate, globe, check and plug valves: forged bodies, bonnets, seat rings, stems and valve blocks.
Strainers and manifolds handling reducing acid streams.

Pharmaceutical, fine chemical and other industries

Reactors and crystalliser components in pharmaceutical and biochemical intermediate manufacture.
Herbicide, insecticide, ethylene glycol and ethylbenzene production units.
Pulp and paper digester components, and vacuum furnace internals.

Inspection, testing and certification

Every UNS N10665 forging leaving Jiangyin Jiangnan Metal is supplied with a certificate traceable to the heat number stamped on the piece.

Table 8. Standard and optional inspection scope
Test	Standard	Scope
Chemical analysis	ASTM E1473, spectrometry	Standard, per heat
Tensile test	ASTM E8 / E8M, ISO 6892-1	Standard, per heat and heat-treatment lot
Hardness	ASTM E18 Rockwell	Standard
Grain size	ASTM E112	Standard for forgings
Ultrasonic testing	EN 10228-3, SEP 1921, ASTM A388	Standard; acceptance class agreed at order
Liquid penetrant	ASTM E165, EN ISO 3452	On request
Intergranular corrosion	ASTM G28 method A	On request
Positive material identification	PMI by XRF or OES	On request
Inspection certificate	EN 10204 3.1	Standard
Third-party certificate	EN 10204 3.2	On request: TUV, SGS, BV, Lloyd’s Register

The manufacturer: Jiangyin Jiangnan Metal Co., Ltd.

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory located at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The works forges rings, seamless rolled rings, flanges, round bars, discs, shafts, sleeves, bushings, tube sheets and valve components in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, including UNS N10665 (Hastelloy B-2) and the wider Hastelloy, Inconel, Incoloy and Monel families.

The works is in the Yangtze River delta between Shanghai and Nanjing, where China’s special steel and forging industry is concentrated. Raw material, heat treatment, machining and third-party inspection are all available within a short distance of the plant. Orders are accepted from single prototype pieces to production batches, and export documentation is prepared in-house.

Capability summary

Process: open-die forging and seamless ring rolling. No tooling cost, single pieces accepted.
Grades: nickel alloys including N10665, N10276, N06022, N06625, N08825 and N04400, plus stainless, tool, alloy and carbon steels.
Heat treatment: in-line solution annealing with rapid quench, normalising, quench and temper.
Machining: rough and finish machining to drawing.
Testing: ultrasonic testing to EN 10228-3, SEP 1921 and ASTM A388; mechanical and chemical laboratory.
Certification: EN 10204 3.1 as standard, EN 10204 3.2 with third-party witness on request.

Contact

CompanyJiangyin Jiangnan Metal Co., Ltd.
AddressNo.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Phone+86 189 2135 9659
Emailsales@steelforgepieces.com
Websitewww.steelforgepieces.com

Request a quotation by email Call +86 189 2135 9659

Send a drawing, a sketch or simply the finished dimensions and quantity. A quotation with forging weight, price, lead time and the proposed inspection scope is normally returned within one working day.

Frequently asked questions about UNS N10665

What is UNS N10665?

UNS N10665 is a solid-solution-strengthened nickel-molybdenum alloy containing 26.0 to 30.0 % molybdenum with nickel as the balance and no deliberate chromium addition. It is better known by the trade name Hastelloy B-2, and also as Alloy B2, W.Nr. 2.4617 and NiMo28. It was developed for maximum resistance to reducing acids, in particular hydrochloric acid at all concentrations up to the boiling point.

Is UNS N010665 the same as UNS N10665?

Yes. UNS N010665 is a common misspelling with one extra zero. The correct UNS designation for the nickel-molybdenum alloy known as Hastelloy B-2 is N10665. Both spellings refer to the same material, and Jiangyin Jiangnan Metal Co., Ltd. supplies forgings to the ASTM requirements for N10665.

Which standard covers UNS N10665 forgings?

ASTM B564, and the identical ASME SB-564, is the standard specification for nickel alloy forgings and covers UNS N10665. Related product specifications are ASTM B335 for rod and bar, ASTM B333 for plate, sheet and strip, ASTM B366 for fittings, ASTM B622 for seamless pipe and tube, and ASTM B619 and B626 for welded pipe and tube.

What are the minimum mechanical properties of UNS N10665 forgings?

In the solution-annealed condition ASTM B564 requires a minimum tensile strength of 110 ksi (760 MPa), a minimum 0.2 % offset yield strength of 51 ksi (350 MPa) and a minimum elongation of 40 % in 2 in. or 4D.

Can UNS N10665 be age hardened?

No. UNS N10665 is solid-solution strengthened and is not precipitation hardenable. The only heat treatment applied to forgings is solution annealing at about 1065 °C (1950 °F) followed by rapid quenching. Ageing is not merely ineffective, it is harmful: holding the alloy in the roughly 600 to 900 °C range promotes Ni₄Mo and other intermetallic precipitation that embrittles the material and reduces corrosion resistance.

What is the forging temperature range for UNS N10665?

UNS N10665 is forged between approximately 1232 °C and 982 °C (2250 °F to 1800 °F). Work should stop before the metal falls below about 982 °C, and the forging is then solution annealed at about 1065 °C and rapidly quenched to restore a fully solutioned microstructure.

What is the difference between Hastelloy B-2 and Hastelloy B-3?

Both are nickel-molybdenum alloys with about 28 % molybdenum, but B-3 (UNS N10675) has a modified composition with controlled chromium and iron additions that give it much better thermal stability and far greater tolerance of the 600 to 900 °C range and of oxidising contamination. B-2 (UNS N10665) remains the choice for clean, confirmed reducing hydrochloric acid service, while B-3 is preferred where the process can see thermal excursions or oxidising species such as ferric or cupric ions.

When should UNS N10665 not be used?

UNS N10665 contains essentially no chromium, so it should not be used where oxidising species are present. Ferric ions, cupric ions, dissolved oxygen, nitric acid or nitrates, even at low concentration, sharply increase corrosion rates. It should also not be used for prolonged service in the roughly 600 to 900 °C range because of intermetallic precipitation. For oxidising or mixed-acid duty select Hastelloy C-276, C-22 or Alloy 59 instead.

Who manufactures UNS N10665 open-die forgings in China?

Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, manufactures UNS N10665 (Hastelloy B-2) forged rings, seamless rolled rings, flanges, bars, discs, shafts, sleeves, bushings and tube sheets to ASTM B564. Enquiries: sales@steelforgepieces.com, +86 189 2135 9659.

What inspection and certification is supplied?

Forgings are ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388 as agreed with the customer, with chemical analysis, tensile testing and hardness testing as standard. Certification is issued to EN 10204 3.1, or EN 10204 3.2 counter-signed by a third-party inspection body such as TUV, SGS, BV or Lloyd’s Register when required.

Jiangyin Jiangnan Metal forges the full Hastelloy, Inconel and Incoloy families. The grades most often compared with or substituted for UNS N10665:

Hastelloy B-2 grade overview

The same alloy as this page, viewed from the grade rather than the UNS number.

Hastelloy B-3 (N10675)

The thermally stable successor to B-2. Preferred for new HCl plant.

Hastelloy C-276 (N10276)

Ni-Cr-Mo for mixed oxidising and reducing service and chloride pitting.

Hastelloy C-22 (N06022)

For strongly oxidising media, wet chlorine and ferric chloride.

Inconel 625 (N06625)

General-purpose Ni-Cr-Mo-Nb for seawater, sour gas and high temperature.

Alloy 59 (N06059)

Very low carbon Ni-Cr-Mo with the widest corrosion range of the group.

Standards referenced on this page

ASTM B564 / ASME SB-564, Standard Specification for Nickel Alloy Forgings. Chemical and mechanical requirements for UNS N10665.
ASTM B335, Standard Specification for Nickel-Molybdenum Alloy Rod.
ASTM B333, Standard Specification for Nickel-Molybdenum Alloy Plate, Sheet and Strip.
ASTM B366, Standard Specification for Factory-Made Wrought Nickel and Nickel Alloy Fittings.
ASTM B622, B619 and B626, seamless and welded nickel alloy pipe and tube.
ASTM E8 / E8M, Standard Test Methods for Tension Testing of Metallic Materials.
ASTM E112, Standard Test Methods for Determining Average Grain Size.
ASTM A388, EN 10228-3 and SEP 1921, ultrasonic examination of forgings.
EN 10204, Metallic products, types of inspection documents 3.1 and 3.2.
ISO 6207, 9723, 9724 and 9725 for the NiMo28 designation. JIS H4551 to H4554 for the NW0665 designation.

Written and technically reviewed by the engineering department of Jiangyin Jiangnan Metal Co., Ltd. Published 18 March 2024. Last updated 28 August 2026. Property data is given for engineering guidance and is not a warranty. Design should be based on the certified test report supplied with the material. Corrections and additional data requests are welcome at sales@steelforgepieces.com.