Alloy 625 / UNS N06625

Description

Alloy 625 is a Ni-Cr-Mo alloy that is used for its high strength, high toughness, and its oxidation and corrosion resistance. Strength of alloy 625 is derived from the stiffening effect of molybdenum and niobium on its nickel-chromium matrix. Although the alloy was developed for high temperature strength, its highly alloyed composition provides a high level of general corrosion resistance. Applications include, but are not limited to: sea water applications, aerospace, chemical processing, and nuclear.

Resistance to Oxidation & Corrosion

Alloy 625 has good resistance to oxidation and scaling at high temperatures. At 1800°F, scaling resistance becomes a significant factor in service. It is superior to many other high temperature alloys under cyclic heating and cooling conditions. The high alloy content of alloy 625 enables it to withstand a wide variety of severe corrosive environments. There is almost no attack in mild environments such as fresh and sea water, neutral pH environment, and alkaline media. The high molybdenum content makes the alloy very resistant to pitting and crevice corrosion.

Fabrication and Heat Treatment

Alloy 625 can be formed using various cold and hot working processes. Because the alloy is developed to retain high strength at elevated temperatures, it resists deformation at hot-working temperatures and higher loads are required to cause the material to deform. Hot forming should be performed within a temperature range of 1700 to 2150°F. During cold working, the material work hardens more rapidly than traditional austenitic stainless steel. Alloy 625 has three heat treatments: 1) solution annealing at 2000/2200°F and air quench or quicker, 2) annealing 1600/1900°F and air quenching or quicker, and 3) stress relieving 1100/1500°F and air quenching. Solution annealed material is commonly used for applications above 1500°F where resistance to creep is important. Annealed material is the most used and has the optimum combination of tensile and rupture properties.

Specifications

ASTM B446 Gr. 1, ASME SB446 Gr. 1, AMS 5666, Annealed, ASTM G28 A&B, NACE MRO175/ISO 15156-3, GE S-400/ S-1000, EN10204-3.1, AMS 5599, ASME SB443, ASTM B443, ASTM G28A, NACE MRO175, ASTM B443 GR1, ASME SB443 GR1, AMS 5599

Common Trade Names

INCONEL® alloy 625

INCONEL® is a registered trademark of the Special Metals Corporation group of companies.

Data Sheet

Chemical Composition:

Element Nickel Chromium Iron Molybdenum Niobium
(plus Tantalum)
Carbon Manganese Silicon Phosphorus Sulfur Aluminum Titanium Cobalt*
Avg. Nominal % 56.0 min. 20.0-23.0 5.0 max. 8.0-10.0 3.15-4.15 0.10 max. 0.50 max. 0.50 max. 0.015 max. 0.015 max. 0.40 max. 0.40 max. 1.0 max.

* If determined

Standard Products

Alloy 625 Plate

Alloy 625 Fittings

Alloy 625 Tube

Alloy 625 Pipe

Alloy 625  Bar

Alloy 625 Sheet

Alloy 625 Fasteners

Alloy 625 Flanges

Alloy 625 Welding Product

Alloy 625 Coil

Alloy 625 Plate Shapes

Alloy 625 Custom Profiles

Alloy 625 Forgings

Alloy 625 Machined Parts

Alloy 625 Welded Components