Inconel 625 pipe
1 . Introduction
Inconel Alloy 625 (UNS designation N06625) is a nickel-based superalloy that possesses
high strength properties and resistance to elevated temperatures. It also demonstrates
remarkable protection against corrosion and oxidation. Its ability to withstand high stress
and a wide range of temperatures, both in and out of water, as well as being able to resist
corrosion while being exposed to highly acidic environments makes it a fitting choice for
nuclear and marine applications.
Inconel 625 was developed in the 1960s with the purpose of creating a material
that could be used for steam-line piping. Some modifications were made to its
original composition that have enabled it to be even more creep-resistant and
weldable. Because of this, the uses of Inconel 625 have expanded into a wide range
of industries such as the chemical processing industry, and for marine and nuclear
applications to make pumps and valves and other high pressure equipment.
2.Chemistry
Some chemical properties of Inconel 625 include:
| Cr | Mo | Co | Nb+Ta | Al | Ti | C | Fe | Mn | Si | P | S | Ni | |
| Min | 20 | 8 | -- | 3.15 | -- | -- | -- | -- | -- | -- | -- | -- | Balance |
| Max | 23 | 10 | 1 | 4.15 | .4 | .4 | .1 | 5 | .5 | .5 | .015 | .015 | Balance |
ASTM (American Society for Testing and Materials) for various products made
out of Inconel 625 are as follow:
| Pipe Seamless | Pipe Welded | Tube Seamless | Tube Welded | Sheet/Plate | Bar | Forging | Fitting | Wire |
| B444 | B705 | B444 | B704 | B443 | B446 | – | – | – |
4.Specifications
AMS: 5599, 5666
MS: 5837
ASME: SB 443 Gr 1, SB 446 Gr 1
ASTM: B 443 Gr 1, B 446 Gr 1
EN: 2.4856
ISO: 15156-3
NACE: MR0175-3
UNS: N06625
Werkstoff: 2.4856
5.Heat Treatment
Heat Treatment Inconel 625 is usually strengthened by cold work, with annealing at
temperatures between 1,700 and 1,900F as required to remove the effects of cold work.
Although nominally a solid-solution alloy containing intergranular and intragranular
carbide precipitates, Inconel 625 is not responsive to strengthening heat treatments.
Solution heat treating at 2000 to 2200F dissolves almost all of the secondary carbides.
The major effects of short-time annealing of hot-rolled bar of standard composition are
to affect reductions in tensile strength and hardness.Typically, the annealing heat
treatment most utilized for Inconel 625 is at 1800F.
