Inconel 690 alloy/ UNS N06690/ WNR 2.4642 characteristic, Chemcial composition & Fabrication

Inconel 690 alloy Characteristic

Inconel 690 is a high-Chromium nickel alloy, which is a excellent resistance to fluoride containing hot nitric acid, to stress corrosion cracking caused by alkalis and media containing chloride and polythionic acids, and to many aggresstive aqueous media or in the primary and secondary loops of nuclear reactors. And good resistance to oxidation, sulphidation and metal dusting in hot gases.

Inconel 690 alloy chemical composition:

Ni: ≥58.0

Cr: 27.0-31.0

Fe: 7.0-11.0

C: ≤0.05

Si: ≤0.50

Mn: ≤0.50

S: ≤0.015

Cu: ≤0.50

Fabrication for Inconel 690 alloy:

INCONEL 690 alloy is readily fabricated by converntional techniques for high-nickel alloys. In most working operations, alloy 690 exhibits characteristics similar to those of INCONEL 600. Inconel 690 should be clean before it is heated and should be heated in a low sulfur atmosphere. Furnace atmospheres for open heating should also be slightly reducing to prevent excessive oxidation of the material.

Inconel 686 Alloy Properties, Fabrication & Corrosion

Inconel 686 Alloy Properties

Inconel 686 (UNS N06686)alloy is a low carbon, the most highly alloyed corrosion-resistant alloy, which is outstanding resistance to oxidizing, reducing, and mixed acid environments.

Fabrication for Inconel 686

Hot forming should be between 1600 and 2500℉(870 and 1230℃), with all heavy forming above 2000℉(1090℃). Work hardening during cold forming may make intermediate annealing necessary. Inconel 686 is normally annealed at 2150-2200℉(1180-1200℃), with rapid cooling.

Corrosion of Inconel 686 alloy

1. Resistance to General corrosion: 

General corrosion, an even, uniform attack of the alloy surface, is the most commonly encountered form of corrosion. This type of attack is predictable, which allows effective estimation of the life of components. The corrosion rate is significantly affected by the concentration of the corrosive medium, the presence of contaminants in the medium, and temperature.

15% HCI Boiling: 2mpy

80% H2SO4,93℃: 29mpy

90% H2SO4, 93℃: 8mpy

FGD1, 80℃: 23mpy

FGD2, 105℃: 274mpy

*mpy can be converted to mm/a by multiplying by 0.0254; FGD1: 60%H2SO4+2.5%HCI+0.2%HF+0.5% flyash at 80℃; FGD2: 70% H2SO4+2.5%HCI+0.2%HF at 105℃

2. Resistance to localized corrosion: 

Localized attack, pitting and crevice corrosion, can occur very quickly and lead to premature, unexpected failure. While the general attack of the surface of the component may be very light, a single pit may propagate throught the thickness of the part causing leakage and failure. Crevice corrosion, as the name implies, takes place within the crevices formed by overlapping sections of metal or under tightly adhering deposits.

Nickel 270 alloy/UNS N02270 Application and Physical Properties & Mechanical Properties

Nickel 270 Alloy Application

Nickel 270 alloy can applying at Hydrogen thyatron components, electrical resistance thermometers, platter bars, passive cathode, fluorescent lamp components, electrolytic cell anodes 

The Physical Properties of Alloy 270

Density: 8.91 g/cm3

Electrical Resistivity: 0.075μohm.m

Thermal Conductivity: 86 W/m.℃

Melting Range: 1454℃

The Mechanical Properties

Tensile Strength,min.:50ksi(345Mpa)

Yield Strength, min.: 16ksi(110Mpa)

Elongation: 50%

Hardness: 66max