Alloy 625/Inconel 625 UNS N06625 Pipe/Tube, Flanges, Fittings

Alloy 625 (UNS N06625)


A nickel-chromium-molybdenum alloy with an addition of niobium that acts with the molybdenum to stiffen the alloy's matrix and thereby provide high strength without a strengthening heat treatment. The alloy resists a wide range of severely corrosive environments and is especially resistant to pitting and crevice corrosion. Used in chemical processing, aerospace and marine engineering, pollution-control equipment, and nuclear reactors.

Standard Product Forms

Pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire.

Chemical Composition Wt,%

























































Density,g/ 8.44

Melting Range,℃ 1290-1350

Typical Mechanical Properties

(Solution Annealed)

(1000h) Rupture Strength (1000h) ksi Mpa

1200℉/650℃ 52 360

1400℉/760℃ 23 160

1600℉/870℃ 72 50

1800℉/980℃ 26 18



Alloy 625 is a solid-solution matrix-stiffened face-centered-cubic alloy.


Due to its low carton content and stabilizing heat treatment, Inconel 625 show little tendency to sensitization even after 50 hour at temperatures in the range 650~450℃.

The alloy is supplied in the soft-annealed condition for applications involving wet corrosion (Alloy 625, grade 1), and is approved by TUV for pressure vessels in the temperature range -196 to 450℃.

For high-temperature applications, above approx. 600℃ ,where high strength and resistance to creep and rupture are required, a solution-annealed version (Alloy 625,grade 2) with a higher carbon content is normally employed and available on request in some products forms.

Outstanding resistance to pitting, crevice corrosion, and intergranular attack;

Almost complete freedom from chloride-induced stress-corrosion cracking;

Good resistance to mineral acids, such as nitric, phosphoric, sulphuric and hydrochloric acids;

Good resistance to alkalis and organic acids;

Good mechanical properties.

Corrosion Resistance

The high alloy content of  alloy 625 enable it to withstand a wide variety of severe corrosion environment. In mild environments such as the atmosphere, fresh and sea water, neutral salts, and alkaline media there is almost no attack. In more severe corrosion environment the combination of nickel and chromium provides resistance to oxidizing chemical, whereas the high nickel and molybdenum contents supply resistance to nonoxidizing against sensitization during welding, thereby preventing subsequent intergranular cracking. Also, the high nickel content provides from chloride ion-stress-corrosion cracking.


The soft-annealed version of Alloy 625 (grade 1) is preferred for applications in the chemical process industry, in marine engineering and in pollution control equipment for environment protection. Typical applications are:

1. Superphosphoric acid production equipment;

2. Nuclear wasts reprocessing equipment;

3. Sour gas production tubes;

4. Piping systems and sheathing of risers in oil exploration;

5. Offshore industry and marine equipment;

6. Flue gas scrubber and damper components;

7. Chimney linings.

For high-temperature application, up to approximately 1000℃, the solution-annealed version of Alloy 625 (grade 2) can be used in accordance to the ASME code for pressure vessels. Typical application are:


1. Components in waste gas system and waste gas cleaning plants exposed to higher temperatures;

2. Flare stacks in refineries and offshore platforms;

3. Recuperator and compensators;

4. Submarine diesel engine exhaust systems;

5. Superheater tubes in wastes incineration plants.

We have products:

ASTM B622 / B619 / B626 Bright Annealed Nickel Alloy Tubing For Chemical Industry; ASTM B444 / B829 Alloy 625 Nickel Alloy Seamless Tube; ASTM B829 Inc 625 / Inc 617 Nickel Alloy Seamless Tube; ASTM B829 Alloy 600 / 601 / 625 Nickel Alloy Seamless Tube; Bright Annealed Nickel Alloy Tube , ISO 9001 / PED , ANSI B36.19 ASTM B829 / ASME SB829 , ASTM B167 , ASTM B444; ASTM A269 Welded Capillary Tube SS TP316L Downhle Tube For Oilfield Services; ASTM B366 Alloy 625 / UNS N06625 Nickel Alloy 45 / 90 Degree Elbow; Alloy 625 / UNS N06625 Nickel Alloy Welded Fitting, Elbow, Tee, Reducer; ASTM B829 Alloy 600 / 601 / 625 Nickel Alloy Seamless Pipe; 1/4 UNS N06625 Oilfield Encapsulated Control Line 3lines With Flat Pack; ASTM A269 / ASME SA269 1 / 4 Inch Stainless Steel Welded Super Long Coiled Tube; Alloy 600 / 601 UNS N06600 / N06601 Nickel Alloy Round Rod / Bar; Alloy 601 / 625 N06600 / N06625 Nickel Alloy Sheet; ASTM B670 Alloy 718 / N07718 Nickel Allloy Sheet / Strip; ASTM B443 / ASME SB443 Alloy 625 Nickel Alloy Sheet For Oil Industry; ASTM B366 Alloy 600 / 625 Nickel Alloy Welded Equal Tee Pipe Fitting; ASME SB366 Alloy 926 / UNS N08926 Nickel Alloy Cross Fitting For Connection; Alloy 601 / 625 / 718 Class300 Nickel Alloy Socket Welding Flange For Medical Tube; Class900 ASTM A366 Alloy 600 / UNS N06600 Nickel Alloy Blind Flange; Alloy 825 / 718 Nickel Alloy Steel Sheet For Gas And Oil Industry; ASTM B443 Alloy 625 Nickel Alloy Steel Round Rod / Bar For Oil Industry; Inc 625 / Inc 617 UNS N06625 / N06617 Bright Annealed Nickel Alloy Tube With High Strength; Alloy C276/601/625/825 Nickel Alloy Sheet/Bar/Strip With High Quality; ASTM B443 UNS N06625 Seamless Nickel Alloy 625 Pipe For High Temperature; Nickel Capillary Tube Alloy 825/625 Downhle Welded Coiled Tube For Oilfield Services; Stainless Steel Welding Heat Exchange Tube ASTM A213 For Air Condenser; TP316 Stainless Steel Straight Heat Exchange Tube, ASTM A213 For Chemical Equipment; ASTM A213/269 Heat Exchange Stainless Steel Tubing With A&P Surface For Pressure Vessel; TP321/321H 19.05mm Stainless Steel Tubing Cold Rolled For Boiler; Duplex Steel S31803 31.8mm Seamless/ Welded U Bend Tubing For Desalination; S31803 Duplex Steel Heat Exchanger Tube With Annealed&Pickling Surface; S31803/2205 ASTM A789 Heat Exchanger Seamless /Welded Tube For Petroleum Refining; Petroleum Refining Used S31803/32750 Heat Exchanger Tube; 25.4mm Cold Rolled U Bend Tube Duplex Steel For Heat Exchanger; 25.4mm Cold Rolled S31803 Tube Desalination Used Duplex Steel For Heat Exchanger; Instrumentation Used Nickel Alloy 825/625 Heat Exchange U Tube; Cold Rolled Nickel Alloy Heat Exchange Seamless U Tube With Annealed; Heat Exchange Tube Nickel Alloy 625/825 For Chemical Equipment with BA/AP Surface; Nickel Alloy Cold Rolled Heat Exchange Tube Alloy 625/UNS N06625 For Pressure Vessel; 19.05mm Cold Rolled U Bend Tube Nickel Alloy Seamless For Heat Exchanger; Chemical Equipment Used 31.8mm Cold Rolled Nickel Alloy Straight/ U Bend Tube Corrosion Resistance; Alloy 400/600 Nickel Alloy Heat Exchanger U Bend Tube With Annealed Surface;
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