Inconel 625: Pricing & Fast Supply

Overview & Basics

What is Inconel 625 and what makes it special?

Inconel 625 is a nickel‑based superalloy containing significant chromium, molybdenum and niobium. It has a face‑centred cubic matrix strengthened by molybdenum and niobium in solid solution rather than through precipitation hardening. This metallurgical design makes the alloy non‑magnetic and gives it high strength without the need for age‑hardening treatments . Its excellent corrosion resistance stems from a high Ni/Cr content and molybdenum; these elements resist oxidising and reducing environments as well as pitting and crevice attack . Because the alloy maintains toughness from cryogenic temperatures up to about 980 °C (1800 °F) , it is classed as a superalloy and is ideal for hostile marine, chemical and aerospace service.

Common applications include sea‑water heat‑exchanger tubing, offshore risers, flue‑gas desulphurisation systems, jet‑engine exhaust ducts and bellows . Its fabricability allows seamless tubes, plates, forgings, wire, mesh and additive‑manufactured parts. In Switzerland and across Europe, engineers and buyers often ask “what material group is Inconel 625?” – it sits in the nickel‑chromium superalloy family rather than stainless steel; in fact its microstructure is non‑ferrous and non‑magnetic .

Naming & equivalents

The alloy’s generic designation is UNS N06625. Other common names include Alloy 625, Inconel 625 and NiCr22Mo9Nb. European standards refer to it as Werkstoff Nr 2.4856 and EN NiCr22Mo9Nb. When specifying welding consumables, the AWS filler designation ERNiCrMo‑3 is usually used for both TIG and MIG wire. Inconel 625 should not be confused with Incoloy 825 (a corrosion‑resistant austenitic alloy) or Inconel 718 (a precipitation‑hardened superalloy); see the comparison section below.

Standards & Designations

UNS, ASTM/ASME and AMS

Inconel 625 has been codified in numerous design and procurement standards. Key specifications include:

• UNS N06625 – unified numbering system designation.

• ASTM standards for different product forms: B443 (plate, sheet and strip), B444 (seamless pipe and tube), B446 (rod and bar), B564 (forgings/flanges), B704/B705 (welded pipe) .

• ASME SB‑ standards parallel the ASTM documents for pressure‑vessel code compliance.

• AMS 5581/5599/5666/5879 – aerospace material specifications covering tube, sheet and annealed bar.

Other systems and welding classifications

International equivalents include ISO 15608 (grouping for welding), DIN 2.4856 and EN 10204 for inspection certificates. The alloy is often used in NACE MR0175/ISO 15156‑3 compliant components for sour‑gas service and meets Norwegian NORSOK M‑650 for subsea applications. For welding consumables, AWS ERNiCrMo‑3 or ISO 18274 S Ni 6625 are recommended; electrodes such as Inconel 112 also match the composition .

Composition, Metallurgy & Microstructure

Chemical composition

Inconel 625 derives its properties from a balanced blend of nickel, chromium, molybdenum and niobium. The table below summarises typical nominal ranges .

Phases, precipitates and microstructure

In its annealed condition, Inconel 625 is a single‑phase γ (gamma) matrix strengthened by the solid solution of molybdenum and niobium. During intermediate‑temperature exposure (≈590–760 °C), disc‑shaped γʺ precipitates (Ni₃(Nb,Ti,Al)) may form, giving additional strength but dissolving again when heated above 1093 °C . Higher temperatures or long exposures can also produce δ‑phase (orthorhombic Ni₃Nb) and Laves phases along grain boundaries; these phases reduce toughness but improve grain‑boundary stability . Carbides such as MC, M₆C and M₂₃C₆ precipitate at grain boundaries and within the matrix . Annealing at 1093 °C followed by rapid cooling dissolves delta and Laves phases .

Because Inconel 625 relies primarily on solid‑solution strengthening, it is not age‑hardenable. Mechanical properties remain stable over long service times, making it reliable in critical applications.

Physical Properties

Density, magnetism and thermal/electrical data

The alloy’s density is approximately 8.44 g cm⁻³ (0.305 lb in⁻³) . It is non‑magnetic with a relative magnetic permeability close to 1.0006 in the annealed condition , meaning it will not attract magnets. This makes Inconel 625 attractive for instrumentation and sensitive equipment. The following table summarises selected physical constants .

Temperature limits

Thanks to its solid‑solution strengthening and stable oxide film, Inconel 625 retains strength from cryogenic temperatures up to about 980 °C (1800 °F) . It also shows good oxidation resistance up to 1093 °C (2000 °F) with intermittent service. At the other extreme, the alloy does not embrittle at sub‑zero temperatures, so it is used in liquefied natural‑gas plants and cryogenic vessels.

Mechanical Properties

Strength and modulus

In the annealed condition, Inconel 625 exhibits excellent tensile properties. Corrotherm reports typical ultimate tensile strength (UTS) of 120–140 ksi (830–965 MPa) and yield strength of 60–75 ksi (415–515 MPa) . Elongation ranges from 30 % to 55 % , giving the alloy good ductility. Hardness falls between 145 – 220 HB .

Because these strengths are achieved without precipitation hardening, they remain relatively constant across a wide temperature range. At elevated temperatures, the alloy retains more than half of its room‑temperature strength up to about 650 °C; at cryogenic temperatures it shows no ductile‑to‑brittle transition.

Hardness, ductility and fatigue

Inconel 625 combines moderate hardness with exceptional ductility. A typical Brinell hardness of ~190 HB corresponds to approximately 25–30 HRC. The alloy’s ductility (elongation ≥30 %) translates into good low‑cycle fatigue resistance, and its high fracture toughness is one reason it is widely used in pressure vessels and aircraft tubing. Work‑hardening occurs rapidly during cold working, so care must be taken during forming and machining.

Corrosion, Oxidation & Environments

General corrosion behaviour

One of the chief reasons for choosing Inconel 625 is its wide‑ranging corrosion resistance. The high nickel content (≥58 %) ensures immunity to chloride stress‑corrosion cracking, while chromium forms a passive oxide film and molybdenum suppresses pitting. HP Alloys notes that the alloy resists pitting, crevice corrosion and stress‑corrosion cracking in chloride‑bearing seawater and reduces acids . Its corrosion resistance extends to phosphoric, nitric and sulphuric acids, making it popular for chemical reactors and waste‑handling equipment. Unlike carbon steel, it does not “rust”; galvanic corrosion may occur only if coupled with less noble metals in conductive media, so appropriate gasketing and insulation are recommended.

Oxidation and high‑temperature exposure

Inconel 625 forms a thin, adherent chromium‑oxide layer that protects it during oxidising service up to about 1093 °C. For continuous exposure above ~650 °C, however, the precipitation of δ and Laves phases can embrittle the alloy . Designers therefore balance oxidation resistance against microstructural stability by choosing appropriate heat treatments and limiting service temperature.

Hydrogen, oxygen and embrittlement

The alloy shows good resistance to hydrogen embrittlement because the nickel matrix prevents hydrogen diffusion. It also remains ductile in high‑purity oxygen systems; indeed, Inconel 625 is approved for aerospace oxygen service. However, hydrogen sulphide environments require compliance with NACE MR0175. Always consult specific codes when designing for sour‑gas service.

Processing & Fabrication

Welding and overlay

Inconel 625 is readily weldable by GTAW (TIG), GMAW (MIG), SMAW and SAW processes. The preferred filler metal is ERNiCrMo‑3, which matches the base composition; covered electrodes designated Inconel 112 are also used . A low interpass temperature (<150 °C) and good heat input control minimise segregation and hot cracking. The alloy is often used for weld overlays and cladding of steel components because it imparts excellent corrosion resistance, particularly on offshore platforms and flue‑gas desulphurisation plants. When joining Inconel 625 to stainless steels (304, 316 or duplex grades), suitable nickel‑based filler metals should be used to accommodate differential thermal expansion.

Heat treatment and stress relief

After hot or cold working, Inconel 625 is typically solution annealed at about 1093 °C (2000 °F) followed by rapid quenching in water or air; this dissolves delta and Laves phases and restores ductility . For stress relief of welds or heavily cold‑worked sections, heating at 870 °C (1600 °F) for one hour followed by air cooling is common. Because the alloy does not harden on ageing, there is no precipitation‑hardening treatment.

Machining

Like most nickel‑base superalloys, Inconel 625 exhibits high work‑hardening and poor thermal conductivity. HP Alloys advises using rigid, powerful machine tools with sharp, positive‑rake cutters and low cutting speeds . Coolant is essential, and avoiding tool chatter prevents surface hardening. Carbide or ceramic inserts provide better tool life. When drilling or tapping, slower feeds and speeds than those used for stainless steels are recommended.

Forming, forging and joining

The alloy can be hot‑forged between approximately 1120 °C and 1220 °C. Cold forming is possible using heavy equipment and intermediate annealing. For brazing, filler metals such as BNi‑2 can be used. Passivation/pickling with nitric–hydrofluoric mixtures removes fabrication oxide scales.

Laser processing

Laser cutting produces clean edges on thin sheet, while laser cladding deposits corrosion‑resistant overlays on carbon steel. Laser welding offers deep penetration and low distortion but requires shielding gas (argon or helium) to prevent porosity.

Additive Manufacturing

3D printing routes

Inconel 625 has become a staple material for additive manufacturing (AM) thanks to its weldability and good as‑built properties. The most common techniques are Laser Powder Bed Fusion (LPBF) and Directed Energy Deposition (DED). Powder for LPBF is produced via gas atomisation or plasma rotating electrode processes; particles are 10–45 µm, spherical, and exhibit low oxygen content (<300 ppm) . Powder density is roughly 8.4 g cm⁻³ with a melting range of 1260–1350 °C .

Printing parameters and post‑processing

Typical LPBF parameters include a layer thickness of 20–100 µm, laser power of 195–350 W and scan speeds of 700–850 mm s⁻¹ . Printed parts may then be stress‑relieved, machined and hot‑isostatic pressed to reduce porosity. According to MET3DP, density values of 8.4 g cm⁻³, ultimate tensile strength around 1025 MPa, yield strength ≈550 MPa, elongation ≈35 % and hardness of ≈35 HRC can be achieved after suitable post‑processing .

Powder supply and costs

Major powder suppliers include Sandvik Osprey, Praxair, Carpenter Additive, AP&C and Erasteel . Pricing depends on production method, particle size distribution and certification; typical cost ranges from US$50–100 per kg . Buyers should request documentation such as ASTM B214 sieve analysis and ISO 18274 certificates.

Forms & Industrial Products

BACH INDUSTRY AG stocks Inconel 625 in a variety of semi‑finished and finished forms:

• Long & flat products – round bar, hex bar, rod, flat bar, sheet, plate, strip, foil, coil, billets and rings. Standard bars conform to ASTM B446 and AMS 5666; plates to ASTM B443. Sheets can be supplied in annealed or cold‑rolled tempers.

• Pipes & tubes – seamless and welded pipe/tubing (ASTM B444/B704/B705) are available in sizes from capillary tubes to heavy‑walled pipe. We can advise on pipe schedule charts and pressure ratings to meet ASME design codes.

• Fittings, flanges & valves – elbows, tees, reducers, forged fittings, flanges (weld neck, slip‑on, RTJ), ball and gate valves, thermowells and expansion joints. Many items meet NACE MR0175 for sour service.

• Fasteners & mesh – bolts, nuts, screws, washers, threaded studs, wire and woven mesh. Inconel 625 filament is available for specialty printing. BACH INDUSTRY AG also offers custom machined components.

Our stock network extends across Switzerland, Germany, Austria, Liechtenstein, Belgium and Africa, with rapid shipping to Zurich and neighbouring regions. Contact us for cutting, machining or custom fabrication services.

Design Data, Tools & Charts

Engineering a component from Inconel 625 often starts with the datasheet. Standard technical data sheets from Special Metals, MatWeb, AZoM and aerospace specification AMS 5666 provide comprehensive property tables and heat‑treatment recommendations. Safety data sheets (SDS) outline handling precautions. Online calculators can help estimate bar weight, pipe schedule and round‑bar weight; BACH INDUSTRY AG’s website offers interactive tools to aid selection.

Comparisons

Nickel alloys

Choosing between nickel alloys depends on the required balance of strength, corrosion resistance and cost.

• Inconel 625 vs. Inconel 718 – 718 contains niobium, titanium and aluminium; it is precipitation‑hardenable and offers far higher high‑temperature strength (UTS >150 ksi) but lower corrosion resistance. 625 remains ductile and weldable, making it a better choice for corrosive environments. Price differences reflect the additional alloying and heat‑treatment steps: 718 generally commands a premium.

• Inconel 625 vs. Inconel 600/601 – 600 and 601 have lower molybdenum and niobium; they are less expensive but offer inferior pitting resistance. 601 has aluminium additions for oxidation resistance but is not as strong.

• Inconel 625 vs. 617/725/750 – 617 contains cobalt and is designed for high‑temperature strength; 625 has better aqueous corrosion resistance. 725 is age‑hardened for high strength but used mainly in down‑hole oil tools; 750 (Inconel X‑750) is a precipitation‑hardened aerospace alloy.

Stainless steels and other materials

Compared with 304/316 stainless steel, Inconel 625 delivers superior chloride‑induced pitting and crevice corrosion resistance and retains strength at much higher temperatures. However, it is significantly more expensive. Duplex 2205 and 6Mo (254 SMO) stainless steels offer better strength and pitting resistance than austenitic grades but still fall short of Inconel 625 in extremely aggressive media. Titanium alloys provide high strength‑to‑weight ratios and good seawater resistance but have lower maximum service temperatures and different corrosion susceptibilities. Hastelloy C‑276/C‑22 and Monel 400/K‑500 are alternative nickel alloys – C‑276 excels in reducing acids while Monel has lower strength and is mainly used in marine service. Alloy 20 (a high‑Cr stainless steel) offers good sulphuric acid resistance but cannot match the temperature capability of Inconel 625.

Applications & Case Uses

The unique combination of properties has made Inconel 625 a mainstay in many industries:

• Aerospace – exhaust systems, thrust reversers, bellows, hydraulic tubing, turbine shroud rings and honeycomb structures . The alloy maintains strength in jet exhaust up to 980 °C and resists oxidation.

• Marine & offshore – seawater piping, risers, splash‑zone hardware, pump shafts and cable sheathing. High molybdenum content prevents pitting and crevice corrosion .

• Chemical processing – reactor vessels, distillation columns, heat exchangers and acid piping. Excellent resistance to nitric, phosphoric and sulphuric acids makes it ideal for fertiliser and pollution‑control plants.

• Power generation – superheaters, heat‑recovery steam generators and flue‑gas desulphurisation stacks; the alloy withstands high temperatures and corrosive flue gases .

• Nuclear – waste handling equipment, fuel‑element cladding and super‑critical water systems; good neutron‑irradiation resistance and low cobalt content minimise activation.

• Automotive & motorsport – turbo‑charger housings, manifolds and exhaust headers; Inconel 625 resists oxidation and thermal fatigue during repeated heating cycles.

• Additive manufacturing – lattice structures, lightweight brackets and customised medical implants using LPBF or DED; printed parts show good strength and fatigue life .

• Instrumentation & springs – non‑magnetic properties and stability enable sensor housings, spring seals and bellows in cryogenic service .

Market & Availability

Suppliers & manufacturers

BACH INDUSTRY AG sources Inconel 625 products from qualified mills and works closely with European and US manufacturers. Our network includes Special Metals, Böhler, ATI, VDM Metals and several certified additive‑manufacturing powder producers. We maintain inventory in Zurich and partner with stockists in Germany, Austria, Belgium and Africa to ensure rapid delivery. Whether you need bar stock, plate, welded pipe, flanges, fasteners, welding wire or powder, we can supply materials compliant with ASTM/ASME, NORSOK and NACE standards.

Pricing & scrap

Current prices vary depending on product form, surface finish and order quantity. BACH INDUSTRY AG offers competitive pricing in Swiss francs and euros, factoring in customs duties and logistics for deliveries within Switzerland, Germany, Austria and neighbouring countries.

Item‑level pricing and availability

Because Inconel 625 components range from tiny fasteners to heavy flanges, pricing is best obtained via quotation. Customers can request quotes for round bar, tube, pipe, sheet, plate, wire and powder. We supply cut‑to‑length services and export packaging. For customers in Zurich and elsewhere in Europe, our sales team can advise on local stock availability and lead times.

Conclusion – Partner with BACH INDUSTRY AG

Inconel 625 remains one of the most capable and versatile superalloys available. Its unique blend of corrosion resistance, high‑temperature strength, ductility and weldability makes it a material of choice when failure is not an option. BACH INDUSTRY AG leverages deep technical expertise and a comprehensive stock programme to supply Inconel 625 in bars, plates, pipes, fittings, welding wire, powder and machined parts. Whether you are designing a subsea manifold, specifying welding overlay, developing an aerospace bracket or printing a complex lattice structure, our team can help you select the right product, meet international standards and optimise cost. Contact us today for tailored advice, competitive pricing and reliable delivery across Switzerland, Europe and beyond.