Monel K-500 vs Inconel 718: Marine and Sour Service

By Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier | ISO 9001:2015 | Est. 2012

Contact: sales@hangboalloy.com | hangbo@nickel-alloy.com | WhatsApp (Lisa): +86 13611656360

Quick Answer: Monel K-500, or Inconel 718?

Choose Monel K-500 for seawater, hydrofluoric acid, alkali and marine hardware where yield strength up to 760 MPa is enough; choose Inconel 718 when more than 700 MPa yield, service above 400 °C, or high-strength sour gas duty is required. K-500 is limited by magnetism and a 35 HRC sour-service hardness cap.

Key Takeaways

• Both alloys are age hardened, but the strengthening phase is completely different. Monel K-500 hardens through a Ni3(Al,Ti) gamma-prime precipitate inside a nickel-copper matrix; Inconel 718 hardens through a Ni3Nb gamma-double-prime precipitate inside a nickel-chromium-iron matrix. The kinetics of those two reactions, not the alloy names, decide the ageing cycle, the weldability and the property ceiling.
• Inconel 718 is roughly twice as strong as Monel K-500 in the aged condition. Aged 718 delivers about 1030 MPa minimum yield strength, while K-500 delivers roughly 620–860 MPa depending on whether the bar was hot worked or cold drawn before ageing.
• Monel K-500 is the alloy for hydrofluoric acid, hot caustic and ambient seawater; Inconel 718 is not usable in hydrofluoric acid. The absence of chromium in K-500 is the reason it survives reducing fluoride environments, and the chromium and molybdenum in 718 are the reason it survives chlorides with crevices and oxidising species.
• Magnetism is a hard disqualifier that is often discovered too late. K-500 becomes ferromagnetic below a Curie temperature in the region of 20–50 °C and its permeability climbs as service temperature falls; 718 remains essentially non-magnetic down to cryogenic temperature, which is why 718 dominates non-magnetic downhole and instrument hardware.
• Sour service inverts the strength ranking in practice. NACE MR0175 / ISO 15156 caps the hardness of nickel-copper UNS N05500 at 35 HRC, which pushes K-500 towards the softer end of its strength range, while 718 is permitted at higher hardness in the same standard.
• Never specify either grade by trade name alone. UNS number, product standard, product form and condition must all be on the purchase order, because the same grade in an un-aged condition is soft, visually identical to other bright nickel alloys, and fails in service.

Two Age-Hardenable Nickel Alloys, Two Different Strengthening Phases

The comparison between Monel K-500 and Inconel 718 is not a comparison between two strength levels of the same material family; it is a comparison between two precipitation reactions that happen to share the words "age hardened" on the certificate. Monel K-500 is a nickel-copper alloy, UNS N05500, containing roughly 63 % nickel with 27–33 % copper, and it is hardened by the aluminium and titanium it contains. Those two elements form a coherent, ordered Ni3(Al,Ti) phase — the gamma-prime precipitate — which is dispersed through the nickel-copper lattice by an ageing treatment at around 595–620 °C. Inconel 718 is a nickel-chromium-iron alloy, UNS N07718, containing roughly 50–55 % nickel, 17–21 % chromium and 4.75–5.50 % niobium plus tantalum, and it is hardened by a Ni3Nb phase known as gamma double prime, which is produced by a two-step ageing treatment that first holds near 718 °C and then near 621 °C.

That difference in strengthening mechanism produces four consequences that decide most real selections. First, the precipitate volume fraction and the alloying additions available to support it are much greater in 718, so the achievable yield strength is much higher: 718 reaches about 1030 MPa minimum yield after ageing, while K-500 reaches roughly 620–860 MPa. Second, gamma-double-prime precipitates slowly, which is why 718 is the most weldable of the high-strength superalloys and why it can be welded and then aged without the strain-age cracking that troubles gamma-prime alloys of similar strength. Third, gamma-double-prime is metastable and coarsens quickly above roughly 650 °C, so 718 is a high-strength alloy up to about 650 °C and loses that advantage above it, whereas K-500 is not selected for sustained load much above 480 °C at all. Fourth, both alloys are soft and visually indistinguishable from other bright austenitic nickel alloys before ageing, so hardness and chemistry verification on delivery is not optional.

Our alloy technical knowledge center sets out the gamma-prime and gamma-double-prime families in more detail, and the same logic explains why these two grades are rarely substitutes: a specification written around the corrosion resistance of a nickel-copper alloy is not satisfied by a nickel-chromium-iron alloy, and vice versa.

Chemical Composition Compared: What Each Element Does

The composition table below puts the two standards side by side and states which standard creates each limit. The most important thing to read from it is not the nickel figure, which is high in both alloys, but the elements that are absent: K-500 contains no chromium and no molybdenum, while 718 contains no copper and no significant aluminium-titanium combination in the K-500 sense.

Element	Monel K-500, UNS N05500 (wt %)	Inconel 718, UNS N07718 (wt %)	Function in the alloy	Standard (form)
Ni	63.0 min (balance)	50.0–55.0	matrix of both alloys; provides stability in reducing media	ASTM B865 / ASTM B637
Cu	27.0–33.0	0.30 max	governs K-500 seawater and HF resistance	ASTM B865 / ASTM B637
Cr	—	17.0–21.0	passive film, oxidation and chloride pitting resistance in 718	ASTM B637 / AMS 5662
Nb + Ta	—	4.75–5.50	forms the Ni3Nb gamma-double-prime phase in 718	AMS 5662 / ASTM B637
Mo	—	2.80–3.30	solid-solution strengthening and pitting resistance in 718	AMS 5662 / ASTM B637
Al	2.30–3.15	0.20–0.80	principal gamma-prime former in K-500	ASTM B865 / AMS 5662
Ti	0.35–0.85	0.65–1.15	gamma-prime former; also a gamma-double-prime former in 718	ASTM B865 / AMS 5662
Fe	2.00 max	remainder	718 uses iron as matrix balance, not as an addition	ASTM B865 / ASTM B637
Co	—	1.00 max	residual; controlled in 718	ASTM B637
Mn	1.50 max	0.35 max	deoxidation residual	ASTM B865 / ASTM B637
Si	0.50 max	0.35 max	deoxidation residual	ASTM B865 / ASTM B637
C	0.25 max	0.08 max	low carbon in 718 supports weldability and ageing control	ASTM B865 / ASTM B637
S	0.010 max	0.015 max	controlled for hot workability	ASTM B865 / ASTM B637
B	—	0.006 max	trace addition for grain-boundary strength in 718	ASTM B637

Table note: Composition limits are summarised from the current editions of the ASTM product standards and SAE AMS specifications named in the final column; where a limit differs between product forms, the limit in the standard named on the purchase order governs, and the figures above are not acceptance limits in themselves. Inconel 718 is also controlled for phosphorus in most product forms, and the exact set of trace elements that applies must be read from the controlling revision rather than inferred from this summary. Chemistry verification on delivery is normally performed by PMI to ASTM E1476, with X-ray spectrometry to ASTM E572 as the method reference. The confirming elements differ between the two grades: nickel at 63 % minimum together with copper at 27–33 % identifies K-500 against 316L stainless and against the nickel-chromium alloys, whereas niobium plus tantalum at 4.75–5.50 %, molybdenum at 2.80–3.30 % and titanium at 0.65–1.15 % identify 718 against 625, 600 and the austenitic stainless steels.

Two compositional facts carry directly into the selection decision. The first is that K-500 has no chromium at all. In hydrofluoric acid and in deaerated reducing acids, chromium-bearing alloys cannot maintain a protective oxide film and corrode rapidly, whereas the nickel-copper matrix is thermodynamically stable and forms a protective fluoride film; this is the whole basis of the K-500 case in HF alkylation, HF storage and HF injection service. The second is that the carbon limit of 0.25 % in K-500 is roughly three times the 0.08 % limit in 718. That higher carbon content is tolerable in a nickel-copper alloy but it is one reason why K-500 welding needs more care than 718 welding, and why the welding procedure for K-500 is usually qualified with post-weld ageing rather than as a simple as-welded joint.

Mechanical Properties: Strength, Ductility and the 700 MPa Line

The engineering decision between these two grades usually turns on a single number, and the number is yield strength. Inconel 718 in the solution treated and aged condition delivers a minimum 0.2 % yield strength of about 1030 MPa for sections up to roughly 100 mm, and the alloy is still capable of about 860 MPa at 650 °C. Monel K-500 delivers a minimum yield strength of about 620 MPa when it is hot worked and aged, or about 790 MPa when it is cold drawn before ageing, and its strength falls away much earlier with temperature. That is the origin of the 700 MPa line: above roughly 700 MPa of required design yield strength, K-500 is only marginally usable in its strongest temper, and it is not usable at all if the service also limits hardness.

Grade and condition	Test temperature	Tensile strength	0.2 % yield strength	Elongation	Hardness	Standard basis
Monel K-500, hot worked + age hardened	20 °C	965 MPa min	620 MPa min	20 % min	24–32 HRC typical	ASTM B865 (standard minimum)
Monel K-500, cold drawn + age hardened	20 °C	1100 MPa min	790 MPa min	15 % min	30–40 HRC typical	ASTM B865 (standard minimum)
Monel K-500, annealed (condition A)	20 °C	~690 MPa typical	~280 MPa typical	~45 % typical	~150 HB typical	ASTM B865 (typical, not a standard minimum)
Monel K-500, age hardened	300 °C	~850 MPa typical	~600 MPa typical	~25 % typical	—	typical, not a standard minimum
Monel K-500, age hardened	480 °C	~700 MPa typical	~480 MPa typical	~25 % typical	—	typical, not a standard minimum
Inconel 718, solution treated + aged, up to ~100 mm	20 °C	1240 MPa min	1030 MPa min	12 % min	36–44 HRC typical	ASTM B637 / AMS 5662 (standard minimum)
Inconel 718, solution treated + aged	650 °C	~1000 MPa typical	~860 MPa typical	~15 % typical	—	typical, not a standard minimum
Inconel 718, solution treated only (un-aged)	20 °C	827 MPa min	690 MPa min	12 % min	~20 HRC typical	ASTM B637 (standard minimum)
Inconel 718, cold drawn + aged fastener stock	20 °C	~1380 MPa typical	~1170 MPa typical	~12 % typical	40–46 HRC typical	typical, not a standard minimum
Monel K-500 bar released for sour service	20 °C	—	—	—	27–33 HRC target band	in-house, not a standard requirement

Table note: Values marked as standard minimums are the minimum requirements of the current editions of ASTM B865 and ASTM B637 for the stated condition and product form, and the minimum that applies is the one in the standard named on the purchase order for the diameter being supplied; larger sections in both standards carry lower minimums, and mechanical property minimums are not transferable between product forms. Values marked typical are published or measured ranges and are explicitly not acceptance criteria. The room-temperature tensile test method is ASTM E8/E8M and the elevated-temperature method is ASTM E21; hardness is measured to ASTM E18 or E10, and grain size to ASTM E112. Note that 718 in the un-aged condition is softer than many austenitic stainless steels and is a common source of rejected deliveries, so hardness must be checked at goods-in for both grades.

Reading the table vertically shows why the choice is usually made at the design stage rather than at the purchasing stage. A seawater pump shaft, a valve stem or a bolted flange in a splash zone rarely needs more than 620–700 MPa yield, and K-500 is an excellent answer there because it combines that strength with proven seawater performance and with the machinability of a nickel-copper alloy. A subsea connector, a riser tensioner bolt, a high-pressure completion tool or an aerospace fastener usually needs more than 1030 MPa yield with a margin, and only 718 is available at that level in a grade that is also corrosion resistant and weldable. Where the requirement sits between the two figures, the deciding question becomes the environment rather than the strength, and the environment question is answered by the two tables that follow.

Magnetic Behaviour: The Property That Rules Out K-500 in Some Tools

Neither alloy is sold on a magnetic specification, but magnetism eliminates Monel K-500 from a whole class of applications, and that elimination is frequently missed until a completed component fails a magnetic-signature test. Monel K-500 is ferromagnetic below a Curie temperature that lies in the region of 20–50 °C for this alloy system, and the exact value depends on the nickel-to-copper ratio, on the aluminium and titanium content, on the amount of cold work and on the ageing condition. The practical consequence is that a K-500 shaft, mandrel or fastener that behaves almost non-magnetically in a warm workshop becomes progressively more magnetic as the service temperature falls through seawater temperature and below, and its relative permeability is a heat-specific property rather than a catalogue number. Inconel 718 remains essentially paramagnetic across the whole engineering range, with a relative permeability close to unity at room temperature and no magnetic transition down to cryogenic temperature, which is why 718 is the default material for non-magnetic downhole tools, instrument housings and cryogenic hardware.

Property (20 °C unless stated)	Monel K-500, UNS N05500	Inconel 718, UNS N07718	Basis
Density	~8.44 g/cm³	~8.19 g/cm³	typical, not a standard minimum
Melting range	~1315–1350 °C	~1260–1336 °C	typical, not a standard minimum
Modulus of elasticity	~179 GPa	~200 GPa	typical, not a standard minimum
Thermal conductivity	~17.5 W/m·K	~11.4 W/m·K	typical, not a standard minimum
Electrical resistivity	~0.62 µΩ·m	~1.25 µΩ·m	typical, not a standard minimum
Curie temperature	in the region of 20–50 °C; permeability rises as temperature falls	no magnetic transition in the engineering range	typical, not a standard minimum
Relative magnetic permeability	heat-specific; must be obtained for the delivered heat	close to unity at room and cryogenic temperature	typical, not a standard minimum
Permeability test method	ASTM A342	ASTM A342	test method

Table note: Physical properties are typical published values and are not requirements of ASTM B865 or ASTM B637; neither product standard specifies magnetic permeability, Curie temperature or thermal conductivity, so a magnetic requirement must be written into the order as a separate acceptance criterion and tested to ASTM A342 against an agreed limit. This is the single most common specification gap we see on non-magnetic components: the drawing states a maximum permeability, the purchase order names only the UNS number, and nothing in the delivered documentation measures the property that the design actually depends on. Where a low magnetic signature is mandatory — magnetometer housings, measurement-while-drilling collars, compass-adjacent hardware, degaussing-sensitive structures and cryogenic instrument parts — Inconel 718 should be treated as the default and Monel K-500 as unsuitable unless the specific heat has been measured and accepted.

There is a second, less obvious magnetic consequence for fabrication. Cold work raises the permeability of K-500 further and can make the property vary along a single component, for example between a rolled thread and the shank of the same bolt. Where a non-magnetic requirement exists at all, it should therefore be verified on the finished part rather than on a coupon cut from the bar, and it should be verified at the lowest temperature the part will see rather than at 20 °C.

Corrosion and Environment: Seawater, Hydrofluoric Acid, Alkali and Sour Gas

The environment table is where the two alloys separate decisively, and in three of the six rows the loser is not merely at a disadvantage but is excluded. The governing question remains the one used across the nickel alloy family: does the medium supply an oxidising species, and does the component contain a crevice or a deposit where that oxidising species can be consumed locally? K-500 needs no passive film and therefore tolerates reducing media; 718 needs chromium and molybdenum and therefore tolerates chlorides, oxidising species and crevices.

Environment	Monel K-500	Inconel 718	Preferred choice and reason
Flowing seawater, ambient, clean	very good	good	K-500 on cost, thermal conductivity and long service record
Seawater with crevices, deposits or stagnant zones	moderate	very good	718; chromium and molybdenum resist crevice attack
Chlorinated seawater, high chlorine residual	moderate	good	718; oxidising chlorine is tolerated better by a chromium-bearing alloy
Hydrofluoric acid, anhydrous or aqueous	good	not suitable	K-500; the standard high-strength choice for HF, with Monel 400 used where lower strength is acceptable
Hot concentrated caustic (NaOH, KOH)	very good	moderate	K-500; nickel-copper is the conventional caustic material
Sour gas with H2S and chlorides	acceptable within the 35 HRC hardness limit; strength therefore limited	suitable at higher hardness and strength	718 where the design needs both H2S tolerance and high strength
Mercury, mercury vapour or liquid metal contact	not suitable	not suitable	neither; nickel alloys are attacked by mercury, and the part must be redesigned or shielded
High-pressure hydrogen gas or strong cathodic protection	limited; hydrogen embrittlement and SCC risk at high strength	good, with limits on strength and cleanliness	718 for high-pressure hydrogen, subject to a qualified assessment
Oxidising acids such as nitric acid	limited	limited, and not the usual choice for either	select a purpose-designed grade rather than either of these two
Deaerated reducing acid, no oxidiser present	very good	moderate	K-500; no chromium requirement, uniform low-rate corrosion

Table note: The ratings are relative performance judgements for the two alloy systems and are not design data; where a specific medium, concentration, temperature, chloride level and stress state govern the design, the selection must be supported by actual corrosion rates or by an immersion test with an agreed acceptance criterion. Sour service in oil and gas production is governed by NACE MR0175 / ISO 15156, which lists nickel-copper UNS N05500 with a maximum hardness of 35 HRC and lists UNS N07718 separately at a higher permitted hardness — confirm both against the edition named in the project specification, because the permitted conditions also depend on temperature, chloride content, pH and partial pressure of H2S. Pitting and crevice resistance can be screened to ASTM G48 and intergranular corrosion to ASTM G28, and our NACE MR0175 sour service guide explains how those limits are usually applied in practice.

The hydrofluoric acid row deserves its own paragraph because it is the one case in which the stronger alloy is simply the wrong answer. Hydrofluoric acid is a reducing acid, and it attacks chromium-bearing alloys by preventing the formation of, or dissolving, the passive film on which those alloys depend. Inconel 718 is therefore not a suitable material for HF duty at any concentration, and its use in an HF system is a specification error rather than a marginal judgement. Monel K-500, by contrast, is used for HF pump shafts, agitator shafts, valve stems and fasteners where the mechanical duty exceeds what annealed Monel 400 can carry, and the nickel-copper matrix resists the acid without any need for a passive film. The same reversed logic applies to hot caustic: a 50 % sodium hydroxide stream at 120 °C is a routine K-500 duty and an unusual 718 duty.

The sour gas row is the mirror image, and it is where the 35 HRC hardness cap changes the answer. NACE MR0175 / ISO 15156 permits nickel-copper UNS N05500 in sour service only below a hardness limit of 35 HRC, and the harder, cold-drawn tempers of K-500 sit at or above that ceiling. A sour-service K-500 component must therefore be supplied in a sufficiently soft condition that the yield strength available is closer to 620 MPa than to 790 MPa, which removes K-500 from contention as soon as the design needs more than roughly 700 MPa yield in the presence of H2S. Inconel 718 is listed in the same standard at a higher permitted hardness, so it can be used at the strength the design needs, and it is consequently the standard high-strength choice for sour-service downhole tools, wellhead equipment and high-pressure fasteners. That is the clearest technical basis for the rule stated in the Quick Answer above, and it is also the reason K-500 is more often found in seawater and HF service than in sour hydrocarbon service.

Finally, the mercury row is a prohibition rather than a preference. Mercury attacks nickel alloys, including both Monel and Inconel grades, by a liquid metal embrittlement mechanism that can produce rapid cracking of a loaded component. K-500 and 718 are therefore both unsuitable for mercury service, for mercury-containing instrument fluids, and for downstream locations where mercury carry-over from a gas stream can deposit on a stressed part. Where mercury is present, the answer is to remove the mercury from the stream, to change the alloy family, or to shield the component — not to select a harder grade.

Ageing Cycles, Welding and Post-Weld Heat Treatment

Both grades require a qualified heat treatment cycle, and in both cases the cycle on the certificate is as important as the chemistry. The difference is that K-500's cycle is a single step that must be applied to material whose prior cold work is already fixed, while 718's cycle is a two-step sequence that depends on the prior solution treatment temperature and on the furnace control. The table below gives the customary shop cycles for each grade and states which of them are written into the standards.

Grade	Treatment step	Temperature and time (customary range)	Purpose	Standard basis
Monel K-500	Anneal to condition A	~870–980 °C, then rapid cool	dissolve solute, restore softness and ductility before forming	ASTM B865 (condition A)
Monel K-500	Age hardening	~595–620 °C for about 16 h, air cool	precipitate Ni3(Al,Ti) gamma prime in the nickel-copper matrix	ASTM B865 (ageing treatment)
Monel K-500	Cold work before ageing	cold drawing or rolling to a defined reduction, then age	raises the strength ceiling above the hot-worked temper	ASTM B865 (cold worked + aged tempers)
Monel K-500	Hardness control for sour service	condition and ageing parameters chosen so the finished part stays within the NACE limit	keeps the part below the 35 HRC sour-service ceiling	in-house, not a standard requirement
Inconel 718	Solution heat treatment	~954–982 °C, then cool	dissolve gamma double prime and delta phase before fabrication	AMS 5662 / AMS 5663
Inconel 718	Precipitation hardening, first step	~718 °C for about 8 h	nucleate gamma double prime	AMS 5662
Inconel 718	Precipitation hardening, second step	controlled cool to ~621 °C, hold about 8 h, air cool	grow and stabilise the gamma double prime precipitate	AMS 5662
Inconel 718	Post-weld treatment	full precipitation hardening cycle after welding	restore strength in the weld and the heat-affected zone	AMS 5662 / AWS or ASME procedure qualification
Both grades	Pyrometry and furnace control	instrumentation and surveys to the applicable pyrometry standard	gives evidence that the cycle was actually delivered	AMS 2750 where aerospace or customer requirements apply

Table note: The temperatures and times shown are the customary shop ranges for these grades and the mandatory values, tolerances, thermocouple placement and furnace survey requirements are those of the controlling specification named on the order; where an aerospace or defence specification applies, AMS 2750 pyrometry governs the instrumentation. K-500 material welded in the aged condition loses strength and hardness in the heat-affected zone, so the usual sequence is to fabricate in the annealed condition and to age the finished component, accepting the distortion that the ageing cycle may introduce. Inconel 718 is normally welded in the solution-treated condition and then precipitation hardened; re-solution treatment after welding is generally not required for correct service performance but may be specified for critical weldments.

Three fabrication differences follow from this and they are worth writing into a manufacturing plan. First, K-500 is the more demanding of the two to weld: the higher carbon content and the copper-rich matrix make the weld pool less forgiving than 718, the filler metal is a matching nickel-copper composition, and the procedure should be qualified with post-weld ageing rather than as an as-welded joint. Second, 718 is the easiest of all the high-strength superalloys to weld, precisely because gamma-double-prime precipitation is sluggish and does not cause the strain-age cracking that gamma-prime alloys suffer; this is why welded 718 structures exist in aerospace and space applications where no alternative would be considered. Third, machining behaviour differs enough to affect cost: K-500 machines more like a nickel-copper alloy, with a pronounced tendency to work harden and to produce long ductile chips, while aged 718 is harder, more abrasive on tooling and generally the more expensive of the two to machine per unit volume. Our nickel alloy machining guide covers the tooling, coolant and speed ranges we use for both grades.

Standards and Specifications: Which Document Applies to Which Form

A purchase order that names only "Monel K-500" or "Inconel 718" leaves the supplier free to choose the product standard, the condition and the test frequency, and that freedom is the origin of most disputes on these two grades. The table below is the practical routing rule we apply when we quote: the standard follows the product form, and the condition and revision follow the application.

Monel K-500 is specified to ASTM B865 for rod, bar and wire, to ASTM B864 for plate, sheet and strip, and to the ASTM pipe and tube documents for tubular forms; the aerospace equivalents are the AMS 4675 and AMS 4676 documents for bar, forgings and rings, whose exact titles and current revision letters should be confirmed against the current AMS index (待核). In European practice the grade is designated W.Nr 2.4375 and is described in DIN 17753 for wrought nickel-copper alloys, in the EN system for wrought nickel products, and in GOST 5632 among the corrosion-resistant and heat-resistant grades; the Chinese designation system in GB/T 15007 covers the nickel-copper family, and the specific designation for the age-hardenable grade must be quoted from the current edition of that standard rather than inferred (待核). Japanese users most often specify to JIS G 4901 when a superalloy bar designation is required, although the nickel-copper grades are commonly ordered against the equivalent ASTM document instead (form scope 待核).

Inconel 718 is specified to ASTM B637 for bar, forgings and forging stock, to ASTM B670 for plate, sheet and strip, and to ASTM B906 for the general requirements that apply to flat-rolled nickel alloy products; the aerospace documents are AMS 5662, AMS 5663 and AMS 5664 for bar, forgings and rings, and the corresponding sheet, strip and plate documents, whose current revision letters must be named on the order. ASME adopts ASTM B637 as ASME SB-637 for pressure equipment, and the code edition that governs the project should be named because the scope is not identical to the ASTM document. In Europe the grade is W.Nr 2.4668, in the Chinese system it is the wrought superalloy GH4169 under GB/T 14992, in Japan the equivalent bar designation is NCF 718 under JIS G 4901, and in the GOST system it appears in GOST 5632. Sour service adds NACE MR0175 / ISO 15156 to whichever product standard applies, and oil and gas equipment specifications such as API 6A add their own material classes and hardness limits. Inspection documents for all of this are ordered to EN 10204 as type 2.2, 3.1 or 3.2, and the difference between those types is a documentary difference, not a quality difference.

Selection Rules: Fasteners, Pump Shafts, Valve Stems and Downhole Tools

The rules below are written as a decision sequence rather than as a list of preferences, because most wrong selections on these two grades are made by starting with the alloy and then looking for a justification. Start with the environment, then with the required strength, then with the hardness limit that the environment imposes, then with the temperature, and only then with the cost.

Application	Typical operating conditions	Recommended grade	Reason	Alternative
Seawater pump shaft, 20–60 mm	ambient to 60 °C, 3–6 m/s, abrasive silt	Monel K-500, cold drawn + aged	strength plus seawater resistance, no chromium required	Monel 400 where stress is low
Marine fastener, splash zone and deck hardware	ambient, chloride, no H2S	Monel K-500, hot worked + aged	620 MPa yield is sufficient and the alloy is seawater-proven	718 where higher strength or size limits demand it
Subsea fastener in a sour well	H2S with chlorides, > 700 MPa yield required	Inconel 718, aged	higher permitted hardness in sour service and roughly double the yield strength	Incoloy 925 for lower strength duties
Valve stem and trim, seawater or brackish cooling water	ambient to 80 °C, moderate stress, galling risk	Monel K-500	strength, seawater resistance and galling behaviour	Nitronic 60 or a hard-faced trim
Valve internals and stems in HF alkylation	HF acid, 30–100 °C	Monel K-500 where strength is needed, otherwise Monel 400	chromium-bearing alloys are excluded by the medium	none within the nickel family
Downhole tool body requiring a low magnetic signature	0–150 °C, chloride, high pressure	Inconel 718	essentially non-magnetic at all service temperatures and high strength	other non-magnetic grades where 718 strength is inadequate
Completion tool mandrel in a sour high-pressure well	H2S, chlorides, 100–200 °C	Inconel 718, aged	sour-service listing at the required strength	925 or a qualified corrosion-resistant alloy
High-temperature bolting and turbine hardware	540–650 °C	Inconel 718, aged	strength retention to about 650 °C	Nimonic 80A or Waspaloy where oxidation is more severe
Cryogenic and LNG instrument hardware	−196 to 20 °C	Inconel 718	non-magnetic and tough at low temperature	none of the nickel-copper grades, because K-500 becomes magnetic
Caustic evaporation and handling internals	40–60 % NaOH, to 120 °C	Monel K-500, or Monel 400 for lower stress	conventional caustic material	Nickel 200 where product purity limits nickel pickup
Mercury-containing process or instrument fluid	any	neither grade	liquid metal embrittlement of nickel alloys	redesign, shield, or remove the mercury before the part

Table note: The recommendations above are the conventional selections for these duties and reflect the corrosion and property behaviour of the two alloy systems; the governing documents in a specific project are normally the process licensor's material selection diagrams, the applicable pressure equipment code and the sour service specification. Where an oil and gas equipment standard such as API 6A applies, its material class and hardness limits take precedence over a general preference for one grade, and the sour-service limits of NACE MR0175 / ISO 15156 must be checked against the actual partial pressure of H2S, the chloride level, the temperature and the pH of the produced fluid. Our Monel product range and Inconel product range both cover the grade and condition combinations used in these duties.

Cost Reference and Procurement Verification (2026, EXW Shanghai)

The commercial asymmetry between these two grades surprises many buyers, because the stronger alloy is usually the cheaper one. Inconel 718 is an iron-rich alloy — its matrix balance is iron rather than nickel — so it contains far less nickel per tonne than Monel K-500, which is roughly 63 % nickel plus 27–33 % copper. The result is that 718 bar typically costs appreciably less per kilogram than aged K-500 bar, and the premium for K-500 is paid for the seawater and hydrofluoric acid performance rather than for strength.

Product form	Grade and condition	Reference range, 2026, EXW Shanghai	Basis	Note
Round bar, 20–100 mm	Monel K-500, hot worked + aged	USD 46–80/kg	ASTM B865	ageing cycle and tighter chemistry drive the band
Round bar, 20–100 mm	Inconel 718, solution treated + aged	USD 34–58/kg	ASTM B637 / AMS 5662	iron-rich matrix, lower nickel content
Round bar, 20–65 mm	Monel K-500, cold drawn + aged	USD 55–90/kg	ASTM B865	cold drawing before ageing adds cost and raises strength
Fastener stock and cold drawn bar	Inconel 718, aged	USD 45–75/kg	AMS 5662	small diameters and tight straightness at the top
Plate, 3–20 mm	Monel K-500	USD 50–85/kg	ASTM B864	cut size and non-standard widths carry a premium
Plate, 3–20 mm	Inconel 718	USD 38–62/kg	ASTM B670	—
Seamless tube and pipe	Monel K-500	USD 60–110/kg	ASTM tube and pipe documents for the form (待核)	small quantities and thin walls at the top of the band
Forging stock and near-net forgings	Inconel 718	quotation by drawing	AMS 5662 / AMS 5663	billet price plus forging and heat treatment
Wire, 0.05–10 mm	Monel K-500	USD 60–100/kg	ASTM B865	spring temper and ageing add cost

Table note: Reference range only, 2026, EXW Shanghai, USD/kg, subject to movement in the LME nickel price, in the copper market and in the ferro-niobium market; these figures are indicative and are not a quotation. Actual prices depend on quantity, specification, tolerances, test scope, documentation and delivery terms, and on whether the material comes from stock or from a mill heat with a specific chemistry. K-500 pricing is driven mainly by nickel and copper, while 718 pricing is driven mainly by nickel and by the niobium-bearing additions, so the two grades do not move together and a quotation should always be refreshed rather than extrapolated.

Verification on these two grades has a common core and one grade-specific trap. The common core is chemistry confirmation by PMI to ASTM E1476, with X-ray spectrometry to ASTM E572 as the analytical reference, mechanical testing to ASTM E8/E8M at room temperature, hardness testing to ASTM E18, and inspection documents to EN 10204 type 3.1 or 3.2. The grade-specific trap is condition: because un-aged K-500 and un-aged 718 are both soft and both look like other bright nickel alloys, a delivery can be chemically correct and mechanically wrong, and PMI alone cannot detect it. Hardness testing at goods-in is therefore the single most effective check for both grades, and for sour service it should be performed on the finished part rather than on a coupon, with the results recorded against the NACE limit. Our PMI inspection guide and EN 10204 certificate guide cover both checks in detail, and our 718 procurement whitepaper and Monel K-500 versus Monel 400 comparison set out the related traps for each family.

Standard Index

Standard	Title / scope	Covers	Form
ASTM B865	Nickel-copper-aluminium alloy (UNS N05500) rod, bar and wire	composition + mechanical + heat treatment	bar, rod, wire
ASTM B864	Nickel-copper-aluminium alloy (UNS N05500) plate, sheet and strip	composition + mechanical	plate, sheet, strip
ASTM B866	Nickel-copper-aluminium alloy (UNS N05500) tubular products (form scope 待核)	composition + mechanical	pipe, tube
ASTM B467	Welded nickel-copper alloy pipe including the aluminium-bearing grade (form scope 待核)	composition + mechanical	welded pipe
AMS 4675	Nickel-copper alloy (UNS N05500) bar, forgings and rings, one condition (title and revision 待核)	mechanical + heat treatment	bar, forging, ring
AMS 4676	Nickel-copper alloy (UNS N05500) bar, forgings and rings, second condition (title and revision 待核)	mechanical + heat treatment	bar, forging, ring
ASTM B637	Nickel-chromium-iron alloy (UNS N07718) bar, forgings and forging stock	composition + mechanical	bar, forging
ASTM B670	Nickel-chromium-iron alloy (UNS N07718) plate, sheet and strip	composition + mechanical	plate, sheet, strip
ASTM B906	General requirements for flat-rolled nickel and nickel alloy plate, sheet and strip	general requirements	plate, sheet, strip
AMS 5662	Nickel alloy 718 bar, forgings and rings, solution treated and precipitation hardened	mechanical + heat treatment	bar, forging, ring
AMS 5663	Nickel alloy 718 bar, forgings and rings, further condition and cleanliness controls (revision-dependent)	mechanical + heat treatment	bar, forging, ring
AMS 5664	Nickel alloy 718 bar, forgings and rings, additional condition	mechanical + heat treatment	bar, forging, ring
ASME SB-637	ASME adoption of ASTM B637 for pressure equipment	composition + mechanical	bar, forging
AMS 2750	Pyrometry — furnace classification, instrumentation and surveys	heat treatment control	all forms
NACE MR0175 / ISO 15156	Materials for use in H2S-containing environments in oil and gas production	material and hardness requirements	all forms
API 6A	Specification for wellhead and Christmas tree equipment	equipment material requirements	components
ASTM E8 / E8M	Tension testing of metallic materials at room temperature	test method	—
ASTM E21	Tension testing of metallic materials at elevated temperature	test method	—
ASTM E10 / E18	Brinell and Rockwell hardness testing	test method	—
ASTM E112	Determining average grain size	test method	—
ASTM A342	Permeability of feebly magnetic materials	test method	—
ASTM E1476 / E572	Metals identification by PMI, and X-ray spectrometry of nickel alloys	test method	—
ASTM G48 / G28	Pitting and crevice corrosion in ferric chloride, and intergranular corrosion of nickel-rich alloys	test method	—
EN 10204	Metallic products — types of inspection documents	inspection documents	all forms
DIN 17753	Wrought nickel-copper alloys — composition and properties	composition + properties	wrought forms
W.Nr 2.4375	German material number for the age-hardenable nickel-copper-aluminium alloy	designation	all forms
W.Nr 2.4668	German material number for Alloy 718	designation	all forms
GB/T 15007	Corrosion-resistant alloy grades and designations (nickel-copper family included)	designation + grades	all forms
GB/T 14992	Wrought superalloy grades and designations (Alloy 718 = GH4169)	designation + grades	wrought forms
JIS G 4901	Corrosion-resistant and heat-resistant superalloy bars (Alloy 718 = NCF 718)	composition + mechanical	bar
GOST 5632	Corrosion-resistant, heat-resistant and heatproof steels and alloys — grades	designation + grades	all forms

Table note: Standards are listed by number and scope; where an edition year or revision letter is not quoted, the latest edition applies and the controlling edition is the one named on the purchase order, which for AMS documents includes the revision letter. Entries marked 待核 require confirmation of the exact title, scope or current revision against the issuing body's index before they are written onto a purchase order; we do not quote a standard title from memory on a commercial document. The Chinese designations for the nickel-copper family and the Japanese coverage of those grades should likewise be taken from the current edition of the standard rather than from a cross-reference table, and GB or GOST values must never be substituted for ASTM limits on an ASTM order.

FAQ

Q1: Is Monel K-500 stronger than Inconel 718?

No, and the gap is wide. In the aged condition, Inconel 718 to ASTM B637 and AMS 5662 carries a minimum 0.2 % yield strength of about 1030 MPa with a minimum tensile strength of about 1240 MPa for sections up to roughly 100 mm, whereas Monel K-500 to ASTM B865 carries a minimum yield strength of about 620 MPa when hot worked and aged, or about 790 MPa when cold drawn before ageing, with corresponding tensile strengths of about 965 MPa and 1100 MPa. Typical production values run above those minimums for both grades, but the ranking never changes: 718 is the high-strength alloy of the pair and K-500 is the moderate-strength alloy.

The reason is the strengthening phase. K-500 hardens through a Ni3(Al,Ti) gamma-prime precipitate in a nickel-copper matrix, which limits how much solute can be dissolved and reprecipitated. Inconel 718 hardens through a Ni3Nb gamma-double-prime precipitate supported by niobium, aluminium, titanium and molybdenum in a nickel-chromium-iron matrix, which supports a far higher precipitate volume fraction. The practical threshold is around 700 MPa of required design yield: above that figure K-500 is only marginally usable in its strongest, hardest temper, and above about 790 MPa it is not usable at all.

Q2: Can Monel K-500 and Inconel 718 be used interchangeably?

They can be interchanged only inside a narrow overlap, and outside it each fails in a different way. The overlap is neutral to mildly oxidising chloride service at moderate temperature and moderate stress, where both alloys resist attack and the decision is commercial. In that band K-500 is usually chosen because it is seawater-proven, machines more easily and does not require the niobium-based cost structure of 718.

Outside the overlap, three exclusions decide the answer. Inconel 718 is not usable in hydrofluoric acid at any concentration, because a reducing acid prevents the chromium-rich passive film from forming. Monel K-500 is not usable where a low magnetic signature is required, because it becomes ferromagnetic below a Curie temperature in the region of 20–50 °C. Monel K-500 is not usable for sustained load above roughly 480 °C, because its strength falls away while 718 retains useful strength to about 650 °C. In sour service the two grades can both be considered, but the hardness cap of 35 HRC applied to the nickel-copper grade by NACE MR0175 / ISO 15156 pushes K-500 towards the softer end of its range, so 718 takes the high-strength duties.

Q3: Which alloy should I use for sour gas service containing H2S?

Use Inconel 718 whenever the design needs more than roughly 700 MPa yield strength in the presence of H2S and chlorides, and use Monel K-500 only when the required strength is moderate and the delivered hardness can be held below the sour-service ceiling. NACE MR0175 / ISO 15156 lists nickel-copper UNS N05500 with a maximum hardness of 35 HRC and lists nickel-chromium-iron UNS N07718 separately at a higher permitted hardness, so the same standard permits 718 to be used at strengths that K-500 cannot reach.

The decision is never made on hardness alone. The permitted envelope also depends on the partial pressure of H2S, the chloride concentration, the in-situ pH, the temperature and the stress level, and the standard is applied through those variables rather than through a single limit. Confirm the listing against the edition named in the project specification, because editions differ.

In practice this is why downhole tool bodies, completion mandrels, wellhead fasteners and high-pressure sour-service hardware are dominated by aged 718 and by Incoloy 925 rather than by Monel K-500, while K-500 remains a seawater and hydrofluoric acid material.

Q4: Why is Monel K-500 limited to 35 HRC in sour service?

Because hardness is used in NACE MR0175 / ISO 15156 as the practical proxy for resistance to sulfide stress cracking in precipitation-hardened nickel-copper alloys, and for UNS N05500 the ceiling is 35 HRC. Hardness tracks the amount of cold work and the ageing response, so it is a fast, repeatable and non-destructive check that a supplier, a fabricator and an inspector can all apply to a finished part. Setting a hardness limit also constrains strength, which is why the limit matters commercially rather than only metallurgically.

The consequence for K-500 is significant. Hot worked and aged material typically sits in the 24–32 HRC band, but cold drawn and aged material commonly sits at 30–40 HRC, so the hardest and strongest tempers of K-500 straddle the sour-service ceiling. A sour-service order must therefore state a maximum hardness of 35 HRC explicitly and accept the yield strength that comes with it, which in practice is nearer 620 MPa than 790 MPa. That reduction, not the corrosion performance, is what rules K-500 out of high-strength sour-service designs.

Q5: Is Inconel 718 suitable for hydrofluoric acid service?

No. Hydrofluoric acid is a reducing acid, and reducing acids attack chromium-bearing alloys because the chromium-rich passive film either cannot form or is dissolved as quickly as it forms. Inconel 718 depends on exactly that film for its corrosion resistance, so it is excluded from HF service at any concentration and at any strength level, and specifying it in an HF system is a material selection error rather than a marginal judgement. The failure mode is rapid, general metal loss rather than a slow, predictable rate.

Monel K-500, and Monel 400 where lower strength is acceptable, is the correct family for HF duty. The nickel-copper matrix is thermodynamically stable in the acid without any passive film, and it forms a protective fluoride film that limits further attack across a wide range of concentrations and temperatures. K-500 is used for HF pump shafts, agitator shafts, valve stems and fasteners where the mechanical duty exceeds what annealed Monel 400 can carry.

Two cautions apply to K-500 in HF. The alloy is more susceptible to stress-corrosion cracking than Monel 400 in some HF conditions, so stress levels and the fabrication sequence should be reviewed by the process owner, and a welded K-500 component requires a qualified procedure with post-weld ageing.

Q6: Which alloy is non-magnetic, Monel K-500 or Inconel 718?

Inconel 718 is the non-magnetic choice of the two. Its relative permeability stays close to unity at room temperature and it has no magnetic transition down to cryogenic temperature, which is why it is the standard material for non-magnetic measurement-while-drilling collars, instrument housings and cryogenic hardware. Monel K-500 is ferromagnetic below a Curie temperature in the region of 20–50 °C, and its permeability rises steeply as the service temperature falls below that range, so a K-500 part that behaves almost non-magnetically in a warm workshop becomes distinctly magnetic in cold seawater or at cryogenic temperature.

The exact permeability of K-500 is a heat-specific property that depends on the nickel-to-copper ratio, on the aluminium and titanium content, on the amount of cold work and on the ageing condition, so it cannot be read from a generic datasheet. Where a low magnetic signature is a design requirement, it must be written into the order as a separate acceptance criterion, measured to ASTM A342, and verified on the finished component at the lowest temperature the part will see rather than on a bar coupon at 20 °C.

Q7: What ageing treatment does Monel K-500 require?

The standard ageing treatment for Monel K-500 is a hold at approximately 595–620 °C for about 16 hours followed by air cooling, as written in ASTM B865. Unlike the two-step precipitation cycle used for Inconel 718, it is a single step, but its result depends heavily on the condition of the material before ageing: annealed material softens to roughly 280 MPa yield, hot worked material reaches about 620 MPa minimum, and cold drawn material reaches about 790 MPa minimum yield after the same ageing hold. The cold work performed before ageing, not the ageing itself, is what sets the strength ceiling.

Two practical points follow. First, the order must state the prior condition as well as the ageing treatment, because the same letter designation does not exist for all tempers and the delivered properties differ by a factor of more than two. Second, welding destroys the aged condition locally, so the usual sequence is to weld in the annealed condition and to age the finished component, accepting the distortion that the ageing hold can introduce and allowing for it in the machining sequence. Where sour service applies, the ageing parameters and prior condition must also be chosen so that the finished hardness stays inside the NACE limit.

Q8: How do I verify that Monel K-500 or Inconel 718 has actually been aged?

Hardness testing at goods-in is the most effective single check, because chemistry alone cannot distinguish aged material from un-aged material in either grade. Un-aged K-500 sits at roughly 150 HB and un-aged 718 at roughly 20 HRC, while aged K-500 typically falls in the 24–40 HRC range depending on temper and aged 718 typically falls in the 33–46 HRC range depending on product form and section size. A hardness result in the soft band tells you immediately that the ageing cycle was not applied, and it is visible within minutes of opening the delivery.

Chemistry verification by PMI to ASTM E1476 remains the check that confirms identity, with niobium, molybdenum and titanium confirming 718 and nickel plus copper confirming K-500. Tensile testing to ASTM E8/E8M confirms the full property set where the specification requires it, and the inspection document type should be stated to EN 10204. At Hangbo Alloy we test hardness on every aged delivery, verify chemistry by PMI, and issue mill test certificates to EN 10204 3.1 with the heat number traceable to the ageing record, because a certificate that shows the ageing cycle but not the hardness result proves very little.

Q9: Which alloy is better for seawater pump shafts and marine fasteners?

Monel K-500 is the conventional answer for both, and Inconel 718 is the answer when the duty exceeds what K-500 can carry. A seawater pump shaft or sleeve at ambient to 60 °C with abrasive silt present needs roughly 620–790 MPa yield strength, resistance to flowing seawater without crevice attack worsening over time, and freedom from chloride stress-corrosion cracking; K-500 delivers all three, has been used in this duty for decades, and machines more easily than aged 718. Deck hardware, splash-zone bolting and brackish-water valve stems are similar cases, and in these duties hot worked and aged K-500 is normally sufficient.

Inconel 718 takes over when the required yield strength exceeds roughly 700 MPa with a margin, when the component is large and a higher strength per unit section is needed, when the service temperature exceeds about 480 °C, or when the seawater environment also contains H2S and the sour-service rules apply. It is also the correct answer wherever a low magnetic signature is required, since K-500 becomes ferromagnetic at seawater temperature.

Both alloys resist chloride stress-corrosion cracking far better than the austenitic stainless steels, so the choice between them is normally decided by strength, temperature, magnetism and cost rather than by cracking risk.

Q10: Can Monel K-500 be welded, and what post-weld treatment is needed?

Monel K-500 can be welded, but it is appreciably less forgiving than Inconel 718 and the procedure must be qualified with the post-weld heat treatment included. The filler metal is a matching nickel-copper composition, welding is normally performed with the parts in the annealed condition, and the finished fabrication is then aged so that the weld and the heat-affected zone recover usable strength. Welding in the aged condition is technically possible but leaves a softened heat-affected zone that cannot be restored without re-solution treatment, so it should be avoided on load-bearing joints.

Inconel 718 is the most weldable of the high-strength superalloys because gamma-double-prime precipitation is sluggish and does not produce the strain-age cracking that troubles gamma-prime alloys of similar strength. It is welded in the solution-treated condition and then precipitation hardened, and re-solution treatment after welding is generally not required for service performance, although it may be specified for critical weldments.

For both grades, state the welding procedure specification on the order, qualify it to the applicable code, and confirm that the post-weld cycle is captured in the same furnace record that governs the final mechanical properties.

Q11: How much do Monel K-500 and Inconel 718 cost per kilogram in 2026?

Reference ranges for 2026, EXW Shanghai, are USD 46–80/kg for hot worked and aged K-500 round bar, USD 55–90/kg for cold drawn and aged K-500 bar, and USD 34–58/kg for solution treated and aged 718 bar; plate, tube and wire sit in comparable bands, and forgings are quoted by drawing. These are reference ranges only and are subject to movement in the LME nickel price, in the copper market and in the ferro-niobium market, so they should be refreshed rather than extrapolated from an older quotation.

The commercial point that surprises buyers is that 718 is usually the cheaper alloy per kilogram even though it is roughly twice as strong. Inconel 718 uses iron as its matrix balance and contains far less nickel than K-500, which is about 63 % nickel plus 27–33 % copper, so the K-500 premium is paid for seawater and hydrofluoric acid performance rather than for strength. Where both grades are technically acceptable, the cheaper one is usually 718, and the corrosion engineering should be revisited before K-500 is selected on habit.

Q12: What is the maximum service temperature for each alloy?

Monel K-500 is a moderate-temperature material. Its aged strength falls progressively above about 300 °C, and it is not normally selected for sustained load above roughly 480 °C, where the aged gamma-prime precipitate coarsens and the yield strength drops away; it is not a high-temperature alloy and should not be treated as one. For hot, high-pressure service, a different grade from the nickel-chromium family is the correct answer.

Inconel 718 retains high strength to about 650 °C and is commonly used to roughly 700 °C where oxidation rather than creep governs, which is why it dominates turbine and engine hardware in that band. Its limit is set by the gamma-double-prime precipitate, which coarsens quickly above roughly 650 °C, and above about 700 °C the selection usually moves to a gamma-prime alloy such as Waspaloy or Nimonic 80A, or to an oxide-dispersion or solid-solution grade.

Between the two, the practical crossover is around 480 °C: below it K-500 can be considered if the environment favours a nickel-copper alloy, and above it 718 is the realistic choice regardless of environment.

Conclusion and Selection Rules

The choice between Monel K-500 and Inconel 718 reduces to four questions asked in the right order. Is the environment hydrofluoric acid, hot caustic or reducing? If yes, the answer is K-500, and 718 is excluded. Does the design need more than roughly 700 MPa yield strength, or service above 480 °C? If yes, the answer is 718, and K-500 is marginal or unusable. Does the component require a low magnetic signature? If yes, the answer is 718, because K-500 becomes ferromagnetic below a Curie temperature in the region of 20–50 °C. Is the service sour, with H2S present? If yes, check the NACE MR0175 / ISO 15156 hardness limit first, because the 35 HRC ceiling on nickel-copper UNS N05500 pushes K-500 down to the softer end of its strength range and hands the high-strength duties to 718.

Three mistakes account for most of the failures we investigate on these two grades. The first is specifying an alloy by trade name without a UNS number, product standard, condition and hardness requirement, which allows un-aged material or a substitute grade to be delivered against a chemically plausible certificate. The second is treating "age hardened" as a transferable property, when K-500 and 718 harden by different reactions with different kinetics and different temperature limits. The third is deciding on price before deciding on environment, which in these two grades means paying more for the weaker alloy in an application where the stronger one would have been acceptable.

Shanghai Hangbo Alloy Group Co., Ltd. supplies Monel K-500 to ASTM B865, B864 and the related tubular documents — covering annealed, hot worked and aged, and cold drawn and aged conditions — together with Inconel 718 to ASTM B637, B670 and AMS 5662, 5663 and 5664, in bar, plate, sheet, seamless tube, pipe, wire and forgings. Material is supplied with mill test certification to EN 10204 3.1, chemistry verification by PMI to ASTM E1476, hardness testing to ASTM E18 on every aged delivery, mechanical testing to ASTM E8/E8M and E21, and third-party inspection by SGS, BV or TUV on request. Send the medium, the concentration, the temperature, the required strength and the hardness limit through our contact page and we will confirm the grade, the condition and the verification scope, and quote the material in the form you need; our news and technical articles cover the related selection decisions across the rest of the nickel alloy family.

Contact & Complete Product Range

Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier

Email: sales@hangboalloy.com | WhatsApp (Lisa): +86 13611656360 | www.nickel-alloy.com

All Grades

Ni: NI200-N6 | Monel: 400-502, K-500, R-405 | Inconel: 600-740H, X-750, 725 | Incoloy: 800-27-7MO | Hastelloy: C-276-HYBRID-BC1, N | Super Austenitic: 904L-AL-6XN | Chromium-Rich: Alloy 33 | High-Strength Stainless: Nitronic 50/60, PH13-8Mo | Chlorination: Alloy 45 | Nimonic: 75-263 | Haynes: 25-HR-160 | RA: 330/333 | Precision: 1J22-4J45 | High-Strength: 18Ni250-AerMet100 | Heating: Cr20Ni80/60 | Specialty: Alloy 20-602CA

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