Illustrative Inconel 625 weld neck flange and elbow in an offshore process setting

Nickel alloys / UNS N06625

Inconel 625 / UNS N06625 Material Data for Flanges and Pipe Fittings

Source-controlled Inconel 625 data for procurement teams and materials engineers reviewing nickel alloy flanges, forged components, and pressure-piping fittings for chloride, seawater, chemical, and elevated-temperature service. This benchmark page connects UNS identity, ASTM product routes, published chemistry and property references, corrosion behaviour, inspection planning, related grades, and RFQ guidance without presenting unverified values as authority.

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Quick technical snapshot

Verified facts first, project assumptions second.

The snapshot is published only from controlled structured data. Anything that needs review stays out of the authoritative display.

Published service span

Cryogenic to 1800 deg F / 982 deg C

Design code, pressure class, wall thickness, and medium still govern suitability.

Service at 1200 deg F and below

Hot-finished, cold-finished, or annealed condition may be selected depending on requirements

Service above 1200 deg F

Annealed or solution-treated material is identified for best service; solution-treated condition is used where creep or rupture resistance is important

Inconel 625 / UNS N06625 verified technical snapshot
Specification	Verified value	Unit
UNS	N06625	-
ASTM specifications	ASTM B446, B564, B443, B444/B829, B704/B751, B705/B775, B366Product-form standards must be confirmed against drawing, pressure class, fitting class, and purchase specification.	-
Alloy family	Nickel-chromium-molybdenum-niobium	-
Density	8.44	g/cm3
General corrosion characteristics	Strong resistance to pitting, crevice attack, chloride-ion stress corrosion cracking, oxidation, and many severe chemical environments	-
Temperature considerations	Cryogenic to 1800 deg F / 982 deg C in published alloy literature; product form, condition, code stress, and application govern final use	-
Typical industries	Offshore, marine, chemical processing, power, nuclear water systems, aerospace process hardware	-

Products and size range

Standard scope for a more complete RFQ.

Each material has its own controlled capability record, giving buyers standard dimensional context before final RFQ specification review.

Flanges

Standard dimensional coverage, pressure-class architecture, facing options, and bore review.

ASME B16.5: NPS 1/2 through NPS 24

ASME B16.47: NPS 26 through NPS 60

Final RFQ confirmation

Butt-weld fittings

Standard NPS / DN architecture, fitting geometry, schedule or wall, and end preparation control.

ASME B16.9: NPS 1/2 through NPS 48

Final RFQ confirmation

Forged fittings

Socket-weld and threaded fitting architecture with class and end-connection review.

ASME B16.11: NPS 1/8 through NPS 4

Final RFQ confirmation

NPS / DN conversion is controlled centrally. Class, bore, schedule, facing, end connection, and RTI capability are reviewed together in the RFQ.

Request custom size

Controlled size architecture

Flange size / class matrix

NPS 1/2 through NPS 24 under ASME B16.5. Standard dimensions are shown for specification planning; availability, manufacturing route, and delivery are confirmed against the final RFQ specification.

Final RFQ confirmation

Class / schedule scope

Classes 150, 300, 400, 600, 900 and 1500. Class 2500 requires the applicable NPS and current governing table to be checked.

Facing / end scope

RF / RTJ as applicable

ASME B16.5 flanges nominal size and configuration guide
Nominal size	DN	Product	Standard	RFQ review
1/2"	DN 15	Flange	ASME B16.5	Final RFQ
3/4"	DN 20	Flange	ASME B16.5	Final RFQ
1"	DN 25	Flange	ASME B16.5	Final RFQ
1-1/4"	DN 32	Flange	ASME B16.5	Final RFQ
1-1/2"	DN 40	Flange	ASME B16.5	Final RFQ
2"	DN 50	Flange	ASME B16.5	Final RFQ
2-1/2"	DN 65	Flange	ASME B16.5	Final RFQ
3"	DN 80	Flange	ASME B16.5	Final RFQ
4"	DN 100	Flange	ASME B16.5	Final RFQ
5"	DN 125	Flange	ASME B16.5	Final RFQ
6"	DN 150	Flange	ASME B16.5	Final RFQ
8"	DN 200	Flange	ASME B16.5	Final RFQ
10"	DN 250	Flange	ASME B16.5	Final RFQ
12"	DN 300	Flange	ASME B16.5	Final RFQ
14"	DN 350	Flange	ASME B16.5	Final RFQ
16"	DN 400	Flange	ASME B16.5	Final RFQ
18"	DN 450	Flange	ASME B16.5	Final RFQ
20"	DN 500	Flange	ASME B16.5	Final RFQ
22"	DN 550	Flange	ASME B16.5	Final RFQ
24"	DN 600	Flange	ASME B16.5	Final RFQ

This table records nominal standard scope, not a promise that every type, class, facing, bore, or material combination is available.

Use the RFQ selector to state product form, NPS / DN, class or schedule, facing or end connection, testing, and documents for review.

Controlled size architecture

Butt-weld fitting size / schedule matrix

NPS 1/2 through NPS 48 under ASME B16.9. Standard dimensions are shown for specification planning; availability, manufacturing route, and delivery are confirmed against the final RFQ specification.

Final RFQ confirmation

Class / schedule scope

Schedule or wall thickness as specified for the fitting geometry

Facing / end scope

Butt-weld bevel

ASME B16.9 butt-weld fittings nominal size and configuration guide
Nominal size	DN	Product	Standard	RFQ review
1/2"	DN 15	Butt-weld fitting	ASME B16.9	Final RFQ
3/4"	DN 20	Butt-weld fitting	ASME B16.9	Final RFQ
1"	DN 25	Butt-weld fitting	ASME B16.9	Final RFQ
1-1/4"	DN 32	Butt-weld fitting	ASME B16.9	Final RFQ
1-1/2"	DN 40	Butt-weld fitting	ASME B16.9	Final RFQ
2"	DN 50	Butt-weld fitting	ASME B16.9	Final RFQ
2-1/2"	DN 65	Butt-weld fitting	ASME B16.9	Final RFQ
3"	DN 80	Butt-weld fitting	ASME B16.9	Final RFQ
4"	DN 100	Butt-weld fitting	ASME B16.9	Final RFQ
5"	DN 125	Butt-weld fitting	ASME B16.9	Final RFQ
6"	DN 150	Butt-weld fitting	ASME B16.9	Final RFQ
8"	DN 200	Butt-weld fitting	ASME B16.9	Final RFQ
10"	DN 250	Butt-weld fitting	ASME B16.9	Final RFQ
12"	DN 300	Butt-weld fitting	ASME B16.9	Final RFQ
14"	DN 350	Butt-weld fitting	ASME B16.9	Final RFQ
16"	DN 400	Butt-weld fitting	ASME B16.9	Final RFQ
18"	DN 450	Butt-weld fitting	ASME B16.9	Final RFQ
20"	DN 500	Butt-weld fitting	ASME B16.9	Final RFQ
22"	DN 550	Butt-weld fitting	ASME B16.9	Final RFQ
24"	DN 600	Butt-weld fitting	ASME B16.9	Final RFQ
26"	DN 650	Butt-weld fitting	ASME B16.9	Final RFQ
28"	DN 700	Butt-weld fitting	ASME B16.9	Final RFQ
30"	DN 750	Butt-weld fitting	ASME B16.9	Final RFQ
32"	DN 800	Butt-weld fitting	ASME B16.9	Final RFQ
34"	DN 850	Butt-weld fitting	ASME B16.9	Final RFQ
36"	DN 900	Butt-weld fitting	ASME B16.9	Final RFQ
38"	DN 950	Butt-weld fitting	ASME B16.9	Final RFQ
40"	DN 1000	Butt-weld fitting	ASME B16.9	Final RFQ
42"	DN 1050	Butt-weld fitting	ASME B16.9	Final RFQ
44"	DN 1100	Butt-weld fitting	ASME B16.9	Final RFQ
46"	DN 1150	Butt-weld fitting	ASME B16.9	Final RFQ
48"	DN 1200	Butt-weld fitting	ASME B16.9	Final RFQ

Elbows, tees, reducers, caps, returns, and stub ends do not share identical dimensional availability. Confirm the exact fitting geometry before quotation.

Use the RFQ selector to state product form, NPS / DN, class or schedule, facing or end connection, testing, and documents for review.

Material overview

Inconel 625 material data for engineering review.

The narrative supports specification review without replacing the engineer's design basis, corrosion review, or purchase standard.

Inconel 625 / UNS N06625 is positioned on the RTI material system as a specification-led nickel alloy for severe corrosion service, elevated-temperature exposure, and procurement packages where document traceability is as important as dimensional supply.

The page intentionally separates manufacturer-published material data from order-specific guarantees. Chemistry, density, and mechanical values are controlled in structured tables, while dimensional supply, pressure class, testing, and certification remain tied to the RFQ and purchase specification.

For flanges and pipe fittings, RTI should treat grade confirmation, product-form standard, heat traceability, PMI requirement, MTC type, TPI attendance, and any NACE sour-service review as mandatory enquiry fields.

Material selection pathway

From alloy identity to release documentation.

UNS

N06625

Chemistry

13 verified rows

Product route

Flanges + Pipe Fittings

Standards

6 standards

Inspection

PMI / MTC / EN 10204 3.1 / TPI / NACE / IGC

Release

Traceable RFQ + MTC review

Chemical composition

Published chemistry reference.

The published chemistry values are structured data and must be reconciled against the actual material certificate for every supplied lot.

Limiting chemical composition - Inconel 625 / UNS N06625
Element	Verified composition	Basis
Nickel	58.0 min	Mass %
Chromium	20.0-23.0	Mass %
Iron	5.0 max	Mass %
Molybdenum	8.0-10.0	Mass %
Niobium plus tantalum	3.15-4.15	Mass %
Carbon	0.10 max	Mass %
Manganese	0.50 max	Mass %
Silicon	0.50 max	Mass %
Phosphorus	0.015 max	Mass %
Sulfur	0.015 max	Mass %
Aluminum	0.40 max	Mass %
Titanium	0.40 max	Mass %
Cobalt	1.0 max if determined	Mass %

Values are source-backed limiting composition values. Final lot chemistry must be read from the material certificate.

Mechanical properties

Verified property data.

Mechanical values are presented with product-form context. Flanges and fittings still follow the ordered ASTM or ASME route.

Room-temperature mechanical properties - published typical values
Form and condition	Tensile strength	0.2% yield strength	Elongation / hardness
Rod, bar, plate - annealed	827-1034 MPa	414-655 MPa	60-30% elongation; 145-220 HB
Rod, bar, plate - solution-treated	724-896 MPa	290-414 MPa	65-40% elongation; 116-194 HB
Sheet and strip - annealed	827-1034 MPa	414-621 MPa	55-30% elongation
Tube and pipe, cold-drawn - annealed	827-965 MPa	414-517 MPa	55-30% elongation
Tube and pipe, cold-drawn - solution-treated	689-827 MPa	276-414 MPa	60-40% elongation

Manufacturer bulletin values are typical composites and not specification minima. Purchase orders should use the applicable ASTM/ASME product standard and the MTC.

Corrosion behaviour

Selection guidance for the corrosion mechanism, not just the alloy name.

These notes are intentionally conservative because medium chemistry, temperature, stress, crevices, fabrication, and cleaning practice govern final suitability.

Aqueous corrosion

High nickel, chromium, molybdenum, and niobium content supports resistance across oxidizing and nonoxidizing chemical environments, with strong performance against pitting and crevice corrosion.

Seawater and chloride service

The grade is widely considered for seawater-related applications because it resists local attack and chloride-ion stress corrosion cracking better than many austenitic stainless options.

Weld sensitization control

Niobium contributes stabilization against sensitization during welding, supporting intergranular cracking resistance when fabrication procedures and heat input are controlled.

High-temperature oxidation

The alloy has published resistance to oxidation and scaling at elevated temperature, but pressure design and allowable stresses must be checked to the governing code.

Available RTI products

Flanges and pipe fittings routed by material standard.

The page template separates product form, material route, dimensional standard, inspection, and final release documents.

Flanges

Forged flange enquiries should capture ASTM B564 / ASME SB564 material route, dimensional standard, pressure class, facing, bore, heat number, PMI, and MTC requirement.

ASTM B564ASME SB564ASME B16.5ASME B16.47

Pipe Fittings

Nickel alloy elbows, tees, reducers, caps, stub ends, socket-weld and threaded fittings should be reviewed against ASTM B366 / ASME SB366 plus dimensional and inspection classes.

ASTM B366ASME SB366ASME B16.9ASME B16.11

Relevant standards

Standards are supply routes, not decoration.

Each enquiry should identify which standard controls the product form, which standard controls dimensions, and which documents prove conformance.

ASTM B564 / ASME SB564

Forgings for nickel alloy flange and forged component supply

ASTM B366 / ASME SB366

Factory-made wrought nickel alloy pressure piping fittings

ASTM B444 / B829

Seamless nickel alloy pipe and tube reference route

ASTM B705 / B775

Welded nickel alloy pipe reference route

ASTM B443

Plate, sheet, and strip feedstock reference

NACE MR0175 / ISO 15156

Sour-service review when the project environment requires it

Applications

Where procurement conversations usually begin.

Applications are signals for engineering review, documentation scope, and grade comparison.

Seawater handling components

Offshore topside piping packages

Chemical process transfer lines

Heat exchanger and transfer piping hardware

Reaction vessels and distillation column internals

Steam-line bellows and flexible process components

Nuclear water service component review

High-integrity marine fittings

Typical industries

Built for severe-service buying environments.

The same grade can behave differently by industry because service media, inspection plans, and owner specifications change.

Offshore

Subsea

Marine

Chemical processing

Oil & Gas

Petrochemical

Power

Nuclear water systems

Quality and inspection

Document control from the first quotation.

For critical alloys, inspection and certificate requirements belong in the RFQ, not as an afterthought before dispatch.

PMI

Positive Material Identification should be specified when grade segregation risk, mixed alloy packages, or critical service traceability is material to the order.

MTC

The material certificate should be matched to heat number, product form, ASTM/ASME standard, chemical analysis, mechanical results, heat treatment, and marking.

EN 10204 3.1

Use EN 10204 3.1 when the buyer requires manufacturer-issued inspection certificate traceability for the supplied lot.

TPI

Third-party inspection points should be defined before production or dispatch, especially for dimensional inspection, marking, packing, and document review.

NACE

For sour service, require project-specific review instead of assuming universal suitability from the alloy name alone.

IGC

Intergranular corrosion review may be specified where welding, heat treatment, or project standards require additional corrosion evidence.

Material comparison

Compare material considerations before approving substitution.

This section frames substitution as an engineering decision, especially where corrosion mechanism, temperature, weld route, or code requirements change.

Inconel 625 comparison signals
Comparison	Inconel 625	Alternate route	Procurement consideration
Versus 316L	Much higher nickel and molybdenum alloying with stronger chloride and severe-chemical positioning	316L is economical and broadly available for moderate corrosion service	Use Inconel 625 where chloride, seawater, sour review, or severe chemical exposure drives grade selection
Versus Super Duplex 2507	Nickel alloy route with broader high-temperature and mixed chemical resistance positioning	2507 offers very high strength and chloride resistance with duplex metallurgy	Compare service medium, design code, galvanic context, weld procedure, and total installed cost
Versus Incoloy 825	Higher strength and high molybdenum-niobium strengthening profile	825 is often reviewed for sulfuric/phosphoric acid and general corrosion packages	Ask the engineer to specify medium, concentration, temperature, oxygen content, and chloride level

Procurement guidance

The RFQ fields that prevent expensive ambiguity.

A strong alloy enquiry names the grade, standard, dimensions, inspection, documentation, packing, and destination before commercial comparison.

State UNS N06625, product form, ASTM/ASME material standard, dimensional standard, pressure class, schedule or bore, and end connection.

Separate material grade from fitting class: ASTM B366 class and ASME B16.9/B16.11 dimensional requirements answer different questions.

Require heat number traceability from raw material through finished component marking and MTC.

Confirm whether the project needs PMI, solution annealing records, NDE, hydrostatic requirements, NACE review, IGC testing, or TPI release.

For welded or fabricated items, include weld procedure, filler metal expectation, post-weld cleaning, and surface finish requirements.

Engineering FAQs

Questions buyers and materials engineers should settle early.

FAQ content is unique to each benchmark material and remains tied to verified structured guidance.

Is Inconel 625 the same as UNS N06625?

For procurement purposes, Inconel 625 is commonly ordered as UNS N06625. The purchase order should still list the exact product standard, heat treatment condition, dimensions, and certificate requirement.

Which ASTM standard is used for Inconel 625 pipe fittings?

ASTM B366 / ASME SB366 is the key wrought nickel alloy fitting standard. The buyer should also specify the dimensional standard, fitting class, construction route, NDE class if applicable, and EN 10204 certificate type.

Which standard is relevant for Inconel 625 flanges?

Forged Inconel 625 flange enquiries commonly refer to ASTM B564 / ASME SB564 for nickel alloy forgings, with ASME B16.5 or ASME B16.47 used for dimensional and pressure-class requirements.

Can this page be used as the final design authority?

No. This page provides published material guidance, but final suitability must be confirmed by the project engineer against process medium, pressure, temperature, code stress, corrosion allowance, and inspection plan.

Why is molybdenum important in Inconel 625?

Molybdenum contributes to resistance against nonoxidizing environments and helps improve resistance to pitting and crevice corrosion. In alloy 625 it works with nickel, chromium, and niobium to support severe-service performance.

Should PMI be requested for Inconel 625 components?

PMI is strongly advisable for mixed-alloy packages and critical service items because it supports grade segregation control before dispatch. RTI should record whether PMI is required at RFQ stage.

Is NACE review automatic for Inconel 625?

No. NACE or sour-service acceptance must be reviewed against the current project environment, product form, hardness and manufacturing route, and the applicable revision of the project specification.

Related materials

Continue the grade comparison.

Internal links connect related alloy families, technical guidance, and RFQ preparation.

Super Duplex UNS S32750 / 2507Compare nickel alloy selection against high-strength super duplex chloride service.Stainless Steel 316LReview where a molybdenum-bearing austenitic stainless grade is sufficient.Nickel AlloysReturn to the wider nickel alloy family architecture.

Related technical guides

Procurement knowledge paths.

These connect material selection to document control, testing, quality review, and RFQ completeness.

PMI and MTC review checklistDocument control questions for critical alloy procurement.Material selection workflowHow RTI separates grade, standard, product, testing, and delivery requirements.

Grade and product route review

Inspection and certificate planning

Traceable quotation package

Structured RFQ

Prepare a cleaner component enquiry

Capture material, standard, dimensions, quantity, inspection, documentation, packing, and destination before the technical quotation is prepared.

Start RFQ

Inconel 625 / UNS N06625 Material Data for Flanges and Pipe Fittings

Verified facts first, project assumptions second.

Standard scope for a more complete RFQ.

Flanges

Butt-weld fittings

Forged fittings

Flange size / class matrix

Butt-weld fitting size / schedule matrix

Inconel 625 material data for engineering review.

From alloy identity to release documentation.

UNS

Chemistry

Product route

Standards

Inspection

Release

Published chemistry reference.

Verified property data.

Selection guidance for the corrosion mechanism, not just the alloy name.

Aqueous corrosion

Seawater and chloride service

Weld sensitization control

High-temperature oxidation

Flanges and pipe fittings routed by material standard.

Flanges

Pipe Fittings

Standards are supply routes, not decoration.

ASTM B564 / ASME SB564

ASTM B366 / ASME SB366

ASTM B444 / B829

ASTM B705 / B775

ASTM B443

NACE MR0175 / ISO 15156

Where procurement conversations usually begin.

Built for severe-service buying environments.

Document control from the first quotation.

PMI

MTC

EN 10204 3.1

TPI

NACE

IGC

Compare material considerations before approving substitution.

The RFQ fields that prevent expensive ambiguity.

Questions buyers and materials engineers should settle early.

Continue the grade comparison.

Procurement knowledge paths.

Prepare a cleaner component enquiry

Have a Technical Requirement?