NW6022 is a fully austenitic nickel-chromium-molybdenum-tungsten corrosion-resistant alloy that stands up to both oxidising and reducing media, and resists pitting, crevice corrosion and chloride stress-corrosion cracking. Jiangyin Jiangnan Metal Co., Ltd. forges NW6022 into seamless rolled rings, flanges, round bars, discs, shafts, sleeves and tube sheets at its open-die forging plant in Jiangyin, Jiangsu, China, and ships worldwide with EN 10204 3.1 or 3.2 certification.
NW6022 is the nickel-chromium-molybdenum-tungsten corrosion-resistant alloy cross-referenced to UNS N06022, Werkstoff number 2.4602 and EN designation NiCr21Mo14W, and sold commercially as Alloy 22 or Hastelloy® C-22. It runs 20.0 to 22.5 % chromium, 12.5 to 14.5 % molybdenum and 2.5 to 3.5 % tungsten with a nickel balance. Carbon and silicon are held very low, at 0.015 % and 0.08 % maximum, which suppresses grain-boundary precipitation in the weld heat-affected zone and lets the alloy be used as welded.
Chromium at around 21 % deals with oxidising media such as nitric acid, wet chlorine and ferric or cupric chloride. Molybdenum and tungsten deal with reducing media such as hydrochloric and sulphuric acid. Plant chemistry often moves between the two, and NW6022 handles that swing without the localised attack that stainless steels and lower-alloyed nickel grades suffer.
NW6022 is solid-solution strengthened, not precipitation hardened, so it is supplied in a single condition: solution annealed and rapidly quenched. Properties stay consistent across the section sizes normally forged.
Equivalent and cross-reference designations
Table 1. NW6022 designations across specification systems
System
Designation
Notes
UNS
N06022
Primary North American designation
Werkstoff (W.Nr.)
2.4602
German material number
EN / DIN chemical
NiCr21Mo14W
DIN 17744, DIN 17750 to 17754
ISO
NiCr21Mo14W3
ISO 6208, ISO 9722
Trade names
Alloy 22, Hastelloy® C-22
Hastelloy is a trademark of Haynes International
Other trade names
Nicrofer® 5621 hMoW
VDM Metals designation
Cast equivalent
ASTM A494 Grade CX2MW
Nearest casting grade
Welding consumables
ERNiCrMo-10, ENiCrMo-10
AWS A5.14 wire, AWS A5.11 electrode
A purchase order written to NW6022, N06022, 2.4602 or Alloy 22 is satisfied by the same heat. Jiangyin Jiangnan Metal states every applicable designation on the mill certificate so the material clears goods inwards without a concession request.
Chemistry
Chemical composition of NW6022
NW6022 contains Cr 20.0 to 22.5 %, Mo 12.5 to 14.5 %, W 2.5 to 3.5 % and Fe 2.0 to 6.0 %, with nickel as balance and carbon limited to 0.015 % maximum. These limits follow DIN 17744 and VdTÜV Werkstoffblatt 479, and match those given for UNS N06022 in ASTM B564, B574 and B462.
Table 2. NW6022 / UNS N06022 chemical composition limits, % by weight
Limit
C
Si
Mn
P
S
Ni
Cr
Mo
Fe
Co
W
V
Min
–
–
–
–
–
bal.
20.0
12.5
2.0
–
2.5
–
Max
0.015
0.08
0.50
0.025
0.020
bal.
22.5
14.5
6.0
2.5
3.5
0.35
Nickel is the balance and is not separately specified. Each heat is verified by spectrographic analysis and the result is reported on the EN 10204 certificate. Positive material identification on the finished forging is available on request.
Why the carbon and silicon limits matter
Carbon is capped at 0.015 % and silicon at 0.08 % for a reason. Both accelerate the precipitation of carbides and of the μ, P and σ intermetallic phases at grain boundaries when the alloy sits in the 600 to 1000 °C range. Keeping them low is what allows NW6022 to be welded and put into service without a post-weld solution anneal, which matters on large fabricated vessels that cannot be furnace-treated after assembly.
Mechanical data
Mechanical properties of NW6022 forgings
Solution-annealed NW6022 forgings meet Rp0.2 of at least 310 N/mm², Rm of at least 690 N/mm² and A5 of at least 45 %. Typical hardness is around 89 HRB and normally does not exceed 100 HRB. Room-temperature modulus of elasticity is about 206 GPa.
The requirement column follows DIN 17744 and ASTM B564 minima for the solution-annealed condition. Typical values are indicative for forged sections and are not guaranteed. The tensile result reported on the mill test certificate for the supplied heat governs acceptance. Test specimens are taken in accordance with the applicable product standard, or from a sacrificial prolongation of the forging itself where the customer specifies that.
Physical data
Physical properties of NW6022
Table 4. NW6022 / UNS N06022 physical properties at 20 °C unless stated
Property
Value
Unit
Density
8.69
g/cm³
Melting range
1357 to 1399
°C
Specific heat capacity
414
J/(kg·K)
Thermal conductivity
10.1
W/(m·K)
Electrical resistivity
1.14
µΩ·m
Mean coefficient of thermal expansion, 20 to 100 °C
12.4
µm/(m·K)
Modulus of elasticity
206
GPa
Magnetic permeability
approx. 1.0002, non-magnetic
–
Crystal structure
Face-centred cubic, fully austenitic
–
PREN, Cr + 3.3 Mo + 1.65 W
approx. 70
–
Values are typical published data for wrought UNS N06022, given for design guidance. PREN is calculated on mid-range chemistry. It places the alloy well above super-duplex and 6 Mo super-austenitic stainless steels for pitting resistance.
Corrosion behaviour
Corrosion resistance of NW6022
NW6022 resists uniform corrosion, pitting, crevice corrosion and chloride stress-corrosion cracking in both oxidising and reducing environments. That combination is why it gets specified for flue-gas desulphurisation, chlorination, pickling, pharmaceutical and hazardous-waste service, where the process chemistry is mixed or upset conditions are expected.
Media the alloy handles well
Oxidising acids and salts: nitric acid, mixed nitric and hydrofluoric, ferric chloride, cupric chloride, hot contaminated seawater and brines.
Reducing acids: dilute to moderately concentrated sulphuric acid, hydrochloric acid, phosphoric acid, formic and acetic acid.
Mixed and upset chemistries: flue-gas desulphurisation scrubbers, incineration scrubbers, sour hydrocarbon streams and acid-gas service.
Behaviour in localised corrosion tests
NW6022 typically shows a critical crevice corrosion temperature above 80 °C in ASTM G48 Method D, and passes ASTM G28 Method A intergranular corrosion testing in the solution-annealed condition. It is accepted under NACE MR0175 / ISO 15156 for sour service and under NACE MR0103 / ISO 17945 for refinery service, subject to the hardness and delivery-condition requirements in those documents.
Before you specify it. Corrosion data is guidance, not a guarantee. Real service performance depends on concentration, temperature, velocity, aeration, contaminants and crevice geometry. On a critical duty, run coupon testing in the actual process fluid before finalising the material selection. Jiangyin Jiangnan Metal can supply NW6022 test coupons from the production heat for that purpose.
Manufacturing route
Melting, forging and heat treatment of NW6022
NW6022 is hot worked between about 1177 °C and 927 °C, then solution annealed at about 1121 °C and rapidly water quenched. The alloy is not age hardenable. Jiangyin Jiangnan Metal melts NW6022 by EAF plus AOD or VOD, and adds electroslag remelting where a cleaner ingot or tighter segregation control is required.
Figure 1. Production route for NW6022 (UNS N06022) open-die forgings at Jiangyin Jiangnan Metal Co., Ltd.
Hot working parameters
Table 5. NW6022 thermal processing parameters
Operation
Temperature
Cooling
Notes
Hot working start
1177 °C
–
Soak thoroughly, avoid overheating above the range
Hot working finish
≥ 927 °C
Air
Reheat rather than continue below this temperature
Solution anneal
1121 °C
Rapid water quench
Mandatory after final hot working
Ageing
Not applicable
Solid-solution strengthened, not precipitation hardened
Stress relief
Full solution anneal only
Intermediate-temperature stress relief is not permitted
A specification error we see often. NW6022 is sometimes ordered as solution treated and aged, by analogy with Inconel 718 or Waspaloy. That is wrong for this alloy. NW6022 gains no strength from ageing, and holding it in the ageing range precipitates intermetallic phases that cut ductility and destroy corrosion resistance. The correct and only delivery condition is solution annealed at about 1121 °C followed by rapid quenching. If your specification carries that clause, query it before the order goes out.
Machining and welding
NW6022 work-hardens fast and has low thermal conductivity. Machine it with positive-rake sharp tooling, rigid setups, heavy positive feed to stay under the work-hardened layer, slow surface speed and generous flood coolant. Dwelling in the cut is the most common cause of tool failure.
GTAW, GMAW and SMAW are all used for welding, with matching ERNiCrMo-10 wire or ENiCrMo-10 electrodes. Keep interpass temperature low, typically below 100 °C. No preheat or post-weld heat treatment is required. Because carbon and silicon are held low, the heat-affected zone keeps its corrosion resistance and the joint can go into service as welded.
Supply range
NW6022 forged product forms and size capability
Jiangyin Jiangnan Metal Co., Ltd. supplies NW6022 as seamless rolled rings, open-die forged rings, flanges, round bars, discs, shafts, sleeves, bushings, tube sheets, hollow bars and valve components, made to customer drawing or to standard dimensions under ASTM B564, ASTM B462, ASTM B574 and DIN 17744.
Table 6. NW6022 forged product forms and indicative size range
Product form
Indicative size range
Typical specification
Seamless rolled rings
OD 200 to 3000 mm, height 50 to 900 mm
ASTM B564 / DIN 17744
Open-die forged rings
OD 100 to 3000 mm
ASTM B564 / DIN 17744
Forged flanges, WN SO BL LJ orifice
DN 15 to DN 1200, Class 150 to 2500
ASTM B462, ASME B16.5 / B16.47, EN 1092-1
Forged round bars
Ø 20 to 800 mm, length to 6000 mm
ASTM B574 / ASTM B564
Forged discs and disks
Ø 100 to 2500 mm
ASTM B564
Forged shafts and spindles
Ø 60 to 900 mm, length to 6000 mm
ASTM B564 / drawing
Forged sleeves and bushings
OD 80 to 1500 mm
ASTM B564 / drawing
Forged tube sheets
Ø to 3000 mm, thickness to 500 mm
ASTM B564 / ASME SB-564
Hollow bars and forged tubes
OD 100 to 1200 mm
To drawing
Valve bodies, blocks and seat rings
To drawing
ASTM B564 / NACE MR0175
Near-net-shape forged blanks
Unit weight 5 to 8000 kg
To drawing
Sizes shown are normal production. Items outside this range are frequently produced. Send the drawing and Jiangyin Jiangnan Metal will confirm feasibility, weight and lead time. Delivery is normally 25 to 45 days depending on section size, machining scope and certification level.
Where it is used
Applications for NW6022 forgings
NW6022 forgings get specified wherever a process alternates between oxidising and reducing chemistry, or carries chlorides at temperature. The main sectors are flue-gas desulphurisation, chemical and pharmaceutical processing, pulp bleaching, hazardous-waste incineration, offshore oil and gas, and acid regeneration plant.
Every NW6022 forging is supplied with an EN 10204 3.1 mill test certificate as standard, and EN 10204 3.2 third-party certification is available on request. Ultrasonic testing is carried out to EN 10228-3, SEP 1921 or ASTM A388, to the acceptance class stated on the order.
Standard scope of testing
Chemical analysis: ladle analysis on every heat, product analysis on request, plus PMI on the finished forging where specified.
Mechanical testing: tensile for Rp0.2, Rm, A5 and Z, plus hardness. Charpy V impact and elevated-temperature tensile by agreement.
Ultrasonic testing: EN 10228-3, SEP 1921 Class 3/D or E, or ASTM A388 to the specified acceptance criteria.
Surface NDT: liquid penetrant testing to ASTM E165 or EN ISO 3452.
Corrosion testing: ASTM G28 Method A intergranular corrosion, ASTM G48 pitting and crevice testing where specified.
Grain size and microstructure: ASTM E112 grain size, micrograph for intermetallic phase check.
Dimensional inspection: full dimensional report against the customer drawing.
Certification and compliance documents
EN 10204 3.1 mill test certificate, issued as standard with every order.
EN 10204 3.2 certificate witnessed by TUV, BV, SGS, DNV, Lloyd's Register or a nominated inspector.
NACE MR0175 / ISO 15156 and NACE MR0103 / ISO 17945 compliance statements for sour and refinery service.
PED 2014/68/EU 4.3 material compliance and AD 2000-Merkblatt W0 documentation on request.
Country-of-origin certificate, heat traceability records and the full melt-to-ship documentation package.
Grade selection
NW6022 compared with C-276, Alloy 59 and Inconel 625
NW6022 carries about 21 % chromium against roughly 15.5 % in C-276, so it performs markedly better in oxidising media such as nitric acid, wet chlorine and ferric chloride. C-276 carries more molybdenum and edges ahead in strongly reducing acids. Inconel 625 has only 8 to 10 % molybdenum and no tungsten, so its localised corrosion resistance is much lower, but it is stronger and better at elevated temperature. NW6022 is the usual choice when a process swings between oxidising and reducing conditions.
Table 8. Nickel alloy comparison, nominal chemistry and characteristics
Grade
UNS
Cr %
Mo %
W %
PREN
Best suited to
NW6022 / Alloy 22
N06022
20.0-22.5
12.5-14.5
2.5-3.5
approx. 70
Mixed oxidising and reducing chemistry, the versatile default
Hastelloy C-276
N10276
14.5-16.5
15.0-17.0
3.0-4.5
approx. 74
Strongly reducing acids, weaker in oxidising media
Alloy 59
N06059
22.0-24.0
15.0-16.5
–
approx. 75
Most aggressive mixed service, higher cost
Hastelloy C-2000
N06200
22.0-24.0
15.0-17.0
–
approx. 76
Sulphuric acid service, copper-bearing variant
Inconel 625
N06625
20.0-23.0
8.0-10.0
–
approx. 51
Higher strength, elevated temperature, seawater
Incoloy 825
N08825
19.5-23.5
2.5-3.5
–
approx. 32
Sulphuric and phosphoric acid, economical, lower resistance
PREN is calculated as Cr + 3.3 Mo + 1.65 W on mid-range chemistry, and is only used for ranking pitting resistance. It does not predict behaviour in specific acids. Jiangyin Jiangnan Metal forges all six grades listed and can quote alternatives side by side against one drawing.
Questions buyers ask
NW6022 frequently asked questions
Is NW6022 the same as Hastelloy® C-22 and Alloy 22?
Yes. NW6022, UNS N06022, W.Nr. 2.4602, NiCr21Mo14W, Alloy 22 and Hastelloy C-22 all describe the same nickel-chromium-molybdenum-tungsten composition, containing 20.0 to 22.5 % chromium, 12.5 to 14.5 % molybdenum and 2.5 to 3.5 % tungsten with a nickel balance. Hastelloy is a registered trademark of Haynes International. NW6022 and Alloy 22 are the generic designations used when the material is not supplied under that trademark. The chemistry limits are identical, so a purchase order written to any of these designations is met by the same heat.
Can NW6022 be age hardened or precipitation hardened?
No. NW6022 is solid-solution strengthened and is not age hardenable. It must be supplied solution annealed at about 1121 °C followed by rapid water quenching. Holding it in the 600 to 1000 °C range precipitates μ, P and σ intermetallic phases at the grain boundaries, which reduces ductility and destroys corrosion resistance. If a specification calls for solution treated and aged NW6022, query that clause before the order is placed.
What is the maximum service temperature for NW6022?
For aqueous corrosion service, NW6022 is used up to roughly 400 °C. Above about 600 °C, prolonged exposure causes intermetallic precipitation that embrittles the alloy, so it is not a long-term high-temperature structural material. For sustained service above 600 °C, Inconel 625, Inconel 617 or Haynes 230 are the appropriate alternatives, and Jiangyin Jiangnan Metal Co., Ltd. forges all three.
Does NW6022 need post-weld heat treatment?
Normally no. Carbon is limited to 0.015 % and silicon to 0.08 %, which suppresses grain-boundary precipitation in the heat-affected zone, so welded joints can go into service in the as-welded condition. Use matching ERNiCrMo-10 filler wire or ENiCrMo-10 electrodes, keep interpass temperature low, typically below 100 °C, and avoid excessive heat input. A full solution anneal is only required if the fabrication has been through a sensitising thermal cycle.
What is the minimum order quantity for NW6022 forgings?
There is no fixed piece-count minimum. NW6022 is melted in heats rather than held in wide stock, so the practical constraint is material availability for the section size ordered. Single prototype forgings and small trial batches are regularly produced alongside a larger heat. Send the drawing or the finished dimensions and quantity to Jiangyin Jiangnan Metal Co., Ltd. at sales@steelforgepieces.com and the works will confirm what is workable and the cost implication.
What is the lead time for NW6022 forgings?
Typical lead time is 25 to 45 days from order confirmation, depending on section size, machining scope and certification level. Third-party witnessed inspection under EN 10204 3.2 usually adds 5 to 10 days for scheduling. If material for the section size is already available, shorter lead times can sometimes be arranged, so state the required date in your enquiry.
Can NW6022 forgings be supplied finish machined?
Yes. Forgings can be supplied as forged, rough machined, proof machined to a defined allowance, or fully finish machined to the customer drawing with a dimensional report. NW6022 work-hardens quickly and machines slowly, so finish machining adds meaningfully to cost and lead time. Many buyers take proof-machined forgings and complete the critical features in their own shop. Both routes are quoted on request.
Which certification and inspection documents come with a NW6022 order?
An EN 10204 3.1 mill test certificate is issued as standard, covering chemical analysis, mechanical test results, heat treatment record, ultrasonic testing result and heat traceability. EN 10204 3.2 certification witnessed by TUV, BV, SGS, DNV or Lloyd's Register is available on request, as are NACE MR0175 / ISO 15156 compliance statements, PED 2014/68/EU material compliance, ASTM G28 Method A corrosion test reports and positive material identification records. Ultrasonic testing is carried out to EN 10228-3, SEP 1921 or ASTM A388.
How are NW6022 forgings packed and shipped?
Forgings are cleaned, edge-protected and packed in fumigation-free plywood cases or on steel pallets with strapping, marked with heat number, grade, drawing number and purchase-order reference. Jiangyin Jiangnan Metal Co., Ltd. ships from Shanghai or Zhangjiagang port on FOB, CIF, CFR or DDP terms, and handles air freight for urgent small items.
Who supplies NW6022 open-die forgings from China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing NW6022 (UNS N06022 / Alloy 22) seamless rolled rings, flanges, bars, discs, shafts and tube sheets for export worldwide. Send drawings and enquiries to sales@steelforgepieces.com or call +86-189-2135-9659.
How do I request a quotation for NW6022 forgings?
Send the drawing or the finished dimensions, the quantity, the specification such as ASTM B564 or DIN 17744, the delivery condition and the certification level to sales@steelforgepieces.com. If no drawing exists, the outside diameter, inside diameter, height or length and quantity are enough to quote. Quotations are normally returned within 24 hours.
The manufacturer
Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The works produces seamless rolled rings, forged flanges, round bars, discs, shafts, sleeves, bushings and tube sheets in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, including NW6022 (UNS N06022 / Alloy 22), Hastelloy, Inconel, Incoloy, Monel and Nimonic grades. Customers are chemical, oil and gas, power, valve and pressure-vessel manufacturers worldwide.
Company
Jiangyin Jiangnan Metal Co., Ltd.
Address
No.1 Chengxiqiao Road Zhouzhuang Town, Jiangyin City Jiangsu Province, China
