What is Nimonic 81 used for?
Nimonic 81 is used for gas turbine components, piston engine and automobile
exhaust valves, and heat-exchange plant attacked by deposits from the combustion of impure
fuels, particularly alkali metal sulfates and chlorides. It is also applied to valve bodies,
seat rings, boiler tube supports, die casting inserts and offshore production hardware.
Is Nimonic 81 the same as UNS N06002?
No. UNS N06002 and W.Nr. 2.4665 refer to Hastelloy X, a solid solution
Ni-Cr-Fe-Mo alloy containing approximately 22 % chromium, 18 % iron and 9 %
molybdenum. Nimonic 81 is a precipitation hardened Ni-Cr alloy with approximately 30 %
chromium and no significant molybdenum or iron. The two grades are frequently confused in
online listings. Nimonic 81 has no widely recognised UNS number, so it should be ordered by
name together with the required chemical composition limits.
How is Nimonic 81 different from Nimonic 80A?
The main difference is chromium content. Nimonic 80A contains approximately
18 to 21 % chromium; Nimonic 81 contains approximately 30 %. Both grades are
hardened by titanium and aluminium additions, their elevated temperature strength
characteristics are broadly comparable, and their melting, hot working, cold working and
machining practices are similar. Nimonic 81 is selected where hot corrosion attack rather
than creep strength limits component life.
What forms of Nimonic 81 forgings can you supply?
Seamless rolled rings, forged flanges, round bars, shafts, discs, blanks,
sleeves, bushings, tube sheets, forged pipe and tube, nozzles, manifolds, gears, rolls and
valve components including bodies, seat rings and stems. All items are forged to the
customer's drawing or size list rather than supplied from stock sizes.
What is the largest Nimonic 81 forging you can produce?
Maximum size depends on section thickness, the reduction ratio required and
the heat treatment involved. A large diameter thin ring and a compact heavy disc are limited
by different factors, so capacity is confirmed per component. Please send the drawing or the
finished dimensions and we will confirm feasibility.
Which certificate do you supply with Nimonic 81 forgings?
EN 10204 3.1 as standard, covering ladle and product chemical analysis,
mechanical test results, heat treatment record and dimensional conformity. EN 10204 3.2
certificates countersigned by a third party inspection body such as BV, SGS, TUV or Lloyd's
are available where the order requires them.
Do you carry out ultrasonic testing?
Yes. Nimonic 81 forgings are ultrasonically tested to EN 10228-3, SEP 1921 or
ASTM A388, depending on which standard and acceptance class the customer specification calls
out. Liquid penetrant testing, hardness survey, impact testing and grain size assessment are
available on request.
What is the lead time and minimum order for Nimonic 81?
Lead time depends on section size, the heat treatment cycle and the
inspection scope, and is confirmed with the quotation. Nimonic 81 is forged to order rather
than held in stock, so a single prototype piece can be produced, at a higher unit price than
a production batch.
Can you rough machine or finish machine the forgings?
Yes. Forgings can be supplied black, rough machined with an agreed machining
allowance, or finish machined to drawing. Please advise the intended machining route at
enquiry stage, since it affects the forging envelope quoted and the amount of material
allowance included.
Where is your factory and can we visit?
Jiangyin Jiangnan Metal Co., Ltd. is located at No.1 Chengxiqiao Road,
Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, approximately two hours from
Shanghai Pudong International Airport and close to the ports of Zhangjiagang and Shanghai.
Customer and third party inspection visits are welcome. Please arrange visits in advance by
email so that the relevant parts are at the appropriate production stage.