| Nickel Alloys |
| Commercially Pure Nickel Alloys |
These alloys contain not less, than 99% of nickel.
Three digit numbers (2xx, 3xx) are used as trade names of commercial
nickel.
The alloys are characterized by very good corrosion resistance and
high ductility.
Alloy 200: Exhibits good corrosion resistance and is ferromagnetic
and has relatively low electrical resistivity. |
| Nickel-Copper Alloys |
These alloys contain about 30% of copper, which form
solid solution with nickel.
This alloy when it contains aluminum and titanium as additional alloying
elements (Alloy K-500), is heat-treatable and may be strengthened by precipitation
hardening.
Alloy 400: The alloy is characterized by moderate strength, good
weldability, good general corrosion resistance and toughness.
Alloy R405: This alloy is a free-machining version of Alloy 400.
This grade contains sulfur to enhance machinability.
Alloy K500: Combines the excellent corrosion resistance characteristic
of Alloy 400 with the added advantages of greater strength and hardness. |
Nickel-Chromium-Iron Alloys
(Non-heat-treatable) |
The major alloying elements of these alloys (15-22%
of chromium and up to 46% of iron) form solid solution with nickel and
may be hardened by cold work.
Alloy 600: Is a nonmagnetic, high temperature alloy possessing
an excellent combination of high strength, hot and cold workability, and
resistance to ordinary form of corrosion. This alloy also displays good
heat resistance and freedom from aging or stress corrosion throughout the
annealed to heavily cold worked condition range.
Alloy 601: An alloy with an addition of aluminum for outstanding
resistance to oxidation and other forms of high temperature corrosion.
It also has high mechanical properties at elevated temperatures.
Alloy 625: The alloy has excellent fatigue strength and stress-corrosion
cracking resistance to chloride ions.
Alloy 718: A precipitation hardenable alloy designed to display
exceptionally high yield, tensile and creep rupture properties at temperatures
up to 1300°F. The sluggish age hardening response of this alloy
permits annealing and welding without spontaneous hardening during heating
and cooling. This alloy has excellent weldability.
Alloy 800: Moderate strength and good resistance to oxidation
and carburization at elevated temperatures. Excellent resistance to chloride
stress corrosion cracking.
Alloy 825: Good corrosion resistance to sulfuric and phosphoric
acids and sea water. It is similar to alloy 800 but with improved resistance
to aqueous corrosion, good resistance in neutral chloride media.
Alloy 925: This is an age-hardenable alloy. The additions of
titanium and aluminum enable it to be age hardened while molybdenum and
copper contents enhance resistance to corrosive media.
Alloy C-276: Excellent general corrosion resistance and good
fabricability. The alloy has resisted both general and localized corrosion,
including pitting, crevice corrosion, and stress corrosion cracking |
Nickel-Chromium-Iron Alloys
(Heat-treatable) |
These alloys may be strengthened by precipitation hardening
due to presence of additional alloying elements: aluminum, titanium, silicon.
Alloy X750: A precipitation-hardenable alloy, the alloy is
highly resistant to chemical corrosion and oxidation and has high stress
rupture strength and low creep rates under high stresses at temperatures
up to 1500°F (816°C) after suitable heat treatment. |
| Nickel-Cobalt Alloys |
These alloys contain about 17% cobalt.
The accepted trade name is Kovar.
Kovar: An iron-nickel-cobalt alloy with a coefficient of thermal
expansion similar to that of hard (borosilicate) glass. This makes it especially
suitable for uses which require a matched expansion seal between metal
and glass parts |
| Nickel-iron-molybdenum Alloy |
HyMu 80: Is 80% nickel-iron-molybdenum alloy
which offers extremely high initial permeability as well as maximum permeability
with minimum hysteresis loss. |
| Maching Classification of Nickel Alloys |
Group A
Alloy 200 |
These alloys are characterized by moderate mechanical strength and
a high degree of toughness. These can be hardened only by cold work.
The alloys are quite gummy in the annealed or hot worked condition, and
cold drawn material is recommended for best machinability and smoothest
finish.
|
Group B
Alloy 400
|
These alloys have higher strength and slightly lower toughness then
those in group A. They can be hardened only by cold work. Cold drawn
or cold drawn, stress-relieved material is recommenced for best machinability
and smoothest finish. |
Group C
Alloy K500-unaged
Alloy 600
Alloy 800
Alloy 825 |
These alloys are quite similar to the austenitic stainless steels.
They can be hardened only by cold work and are machined most easily in
the cold drawn or cold drawn, stress relieved condition. |
Group D
Alloy K500-aged
Alloy 718
Alloy X750 |
These alloys are characterized by high strength and harness, particularly
when aged. Material which has been solution annealed and quenched or rapidly
air cooled is in the softest condition and does machine easily. Because
of softness, the unaged condition is necessary for ease in drilling, tapping
and all threading operations.
Heavy machining of the age hardenable alloys is best accomplished when
they are in one of the following conditions.
1. Solution annealed.
2. Hot worked and quenched or rapidly air cooled.
Although fully age hardened material is usually too hard for tools
with weak cutting edges, such as small drills and taps, and also for rough
machining, material in this condition can be finish machined to fine finishes
and close tolerances.
The best way to machine the alloys in this group is to machine slightly
oversize in the unaged condition, age harden, then finish to size. Because
the age hardening treatment will relieve machining stresses, allowance
must be made for possible warpage. Aged material has good dimensional
stability. |
Group E
Alloy R405 |
This alloy was specifically developed for good machinability.
It is recommended for use with automatic screw machines. Other alloys in
groups A, B, C, and D, may be machined on automatics, but the lower speeds
required are generally not possible with this type of equipment. Alloy
R450 combines the toughness, strength, and corrosion resistance of alloy
400 with excellent machinability. |
| Titanium Alloys |
| Titanium alloys are metallic materials which
contain a mixture of titanium and other chemical elements. Such alloys
have very high tensile strength and toughness (even at extreme temperatures),
light weight, extraordinary corrosion resistance, and ability to withstand
extreme temperatures.
Although "commercially pure" titanium has acceptable mechanical properties,
titanium is alloyed with small amounts of aluminum and vanadium, typically
6% and 4% respectively, by weight. This mixture has a solid solubility
which varies dramatically with temperature, allowing it to undergo precipitation
strengthening. This heat treatment process is carried out after the alloy
has been worked into its final shape, allowing much easier fabrication
of a high strength product.
Some alloying elements raise the alpha-to-beta transition temperature
(i.e. alpha stabilizers) while others lower the transition temperature
(i.e. beta stabilizers). Aluminum, gallium, germanium, carbon, oxygen and
nitrogen are alpha stabilizers. Molybdenum, vanadium, tantalum, niobium,
manganese, iron, chromium, cobalt, nickel, copper and silicon are beta
stabilizers. Titanium alloys are usually classified as alpha alloys, near
alpha alloys, alpha + beta alloy or beta alloys depending on the type and
amount of alloying elements.
Generally, alpha-phase Titanium is more ductile and beta-phase Titanium
is stronger but more brittle. Alpha-beta-phase Titanium has a mechanical
property which is in between both.
Titanium alloys are designated according to their compositions, referred
to as grades: |
| Grade 1-4 |
Unalloyed and considered commercially pure or "CP". Generally the tensile
and yield strength goes up with grade number for these "pure" grades. The
difference in their physical properties is primarily due to the quantity
of interstitial elements. They are used for corrosion resistance applications
where cost and ease of fabrication and welding are important.
|
| Grade 5 |
The most commonly used alloyed. It has a chemical composition of Ti6Al4V.
This alloy contains 6% Aluminum and 4% Vanadium. It is also known as Ti-6AL-4V
or simply Ti 6-4. Grade 5 is used extensively in Aerospace, Medical, Marine,
and Chemical Processing.
|
| Grade 6 |
Contains 5% Aluminum and 2.5% Tin. It is also know as Ti-5Al-2.5Sn.
This alloy is used in airframes and jet engines due to its good weldability,
stability and strength at elevated temperatures.
|
| Grade 7 |
Contains 0.12 to 0.25% Palladium. This grade is similar to Grade 2.
The small quantity of Palladium added gives it enhanced crevice corrosion
resistance at low temperatures and high Ph.
|
| Grade 7H |
Contains 0.12 to 0.25% Palladium. This grade has enhanced corrosion
resistance.
|
| Grade 9 |
Contains 3.0% Aluminum and 2.5% Vanadium. This grade is a compromise
between the ease of welding and manufacturing of the "pure" grades and
the high strength of Grade 5. It is commonly used in aircraft tubing for
hydraulics and in athletic equipment.
|
| Grade 11 |
Contains 0.12 to 0.25% Palladium. This grade has enhanced corrosion
resistance.
|
| Grade 12 |
Contains 0.3% Molybdenum and 0.8% Nickel.
|
| Grades 13, 14, and 15 |
All contain 0.5% Nickel and 0.05% Ruthenium.
|
| Grade 16 |
Contains 0.04 to 0.08% Palladium. This grade has enhanced corrosion
resistance.
|
| Grade 16H |
Contains 0.04 to 0.08% Palladium.
|
| Grade 17 |
Contains 0.04 to 0.08% Palladium. This grade has enhanced corrosion
resistance.
|
| Grade 18 |
Contains 3% Aluminum, 2.5% Vanadium and 0.04 to 0.08% Palladium. This
grade is identical to Grade 9 in terms of mechanical characteristics. The
added Palladium gives it increased corrosion resistance.
|
| Grade 19 |
Contains 3% Aluminum, 8% Vanadium, 6% Chromium, 4% Zirconium, and 4%
Molybdenum.
|
| Grade 20 |
Contains 3% Aluminum, 8% Vanadium, 6% Chromium, 4% Zirconium, 4% Molybdenum
and 0.04% to 0.08% Palladium.
|
| Grade 21 |
Contains 15% Molybdenum, 3% Aluminum, 2.7% Niobium, and 0.25% Silicon.
|
| Grade 23 |
Contains 6% Aluminum, 4% Vanadium.
|
| Grade 24 |
Contains 6% Aluminum, 4% Vanadium and 0.04% to 0.08% Palladium.
|
| Grade 25 |
Contains 6% Aluminum, 4% Vanadium and 0.3% to 0.8% Nickel and 0.04%
to 0.08% Palladium.
|
| Grades 26, 26H, and 27 |
All contain 0.08 to 0.14% Ruthenium.
|
| Grade 28 |
Contains 3% Aluminum, 2.5% Vanadium and 0.08 to 0.14% Ruthenium.
|
| Grade 29 |
Contains 6% Aluminum, 4% Vanadium and 0.08 to 0.14% Ruthenium.
|
| Grades 30 and 31 |
Contain 0.3% Cobalt and 0.05% Palladium.
|
| Grade 32 |
Contains 5% Aluminum, 1% Tin, 1% Zirconium, 1% Vanadium, and 0.8% Molybdenum.
|
| Grades 33 and 34 |
Contain 0.4% Nickel, 0.015% Palladium, 0.025% Ruthenium, and 0.15%
Chromium.
|
| Grade 35 |
Contains 4.5% Aluminum, 2% Molybdenum, 1.6% Vanadium, 0.5% Iron, and
0.3% Silicon.
|
| Grade 36 |
Contains 45% Niobium.
|
| Grade 37 |
Contains 1.5% Aluminum.
|
| Grade 38 |
Contains 4% Aluminum, 2.5% Vanadium, and 1.5% Iron. This grade was
developed in the '90 for use as an armor plating. The iron reduces the
amount of Vanadium needed for corrosion resistance. It's mechanical properties
are very similar to Grade 5.
|
