Jul 3 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
Machining
Welding
Cold Forming
Hot Forming
Other Designations
Applications
Introduction
Nickel alloy 276 is a nickel-molybdenum-chromium-iron-tungsten alloy which is one of the most corrosion-resistant alloy available today. The high molybdenum content in its composition imparts corrosion resistance. However, the low carbon content in turn reduces carbide precipitation during welding in order to maintain resistance to intergranular attack in heat affected zones.
The following section will provide an overview of nickel alloy 276.
Chemical Composition
The chemical composition nickel alloy 276 is outlined in the following table.
|
Element |
Content (%) |
|
Molybdenum, Mo |
15-17 |
|
Chromium, Cr |
14.5-16.5 |
|
Iron, Fe |
4-7 |
|
Tungsten, W |
3-4.5 |
|
Cobalt, Co |
2.5 |
|
Manganese, Mn |
1 |
|
Vanadium, V |
0.35 |
|
Silicon, Si |
0.08 |
|
Phosphorus, P |
0.04 |
|
Sulfur, S |
0.03 |
|
Carbon, C |
0.01 |
|
Nickel, Ni |
Balance |
Physical Properties
The following table shows the physical properties of nickel alloy 276.
|
Properties |
Metric |
Imperial |
|
Density |
8.89 g/cm3 |
0.321 lb/in3 |
|
Melting point |
1325-1370°C |
2415-2500°F |
Mechanical Properties
The mechanical properties of nickel alloy 276 are displayed in the following table.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
690 MPa |
100,000 psi |
|
Yield strength |
283 MPa |
41,000 psi |
|
Elongation at break |
40% |
40% |
Thermal Properties
The thermal properties of nickel alloy 276 are given in the following table
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@93°C/200°F) |
12.24 µm/m°C |
6.8 µin/in°F |
|
Thermal conductivity |
9.8 W/m°C |
67.9 BTU.in/hrft².°F |
Fabrication and Heat Treatment
Machining
Nickel alloy 276 should be preferably machined in the annealed condition. Low cutting speeds are required to be employed as this alloy is prone to work– hardening.
Welding
Nickel alloy 276 can be readily welded using techniques such as gas tungsten arc welding, gas metal arc welding and shielded metal arc welding.
Cold Forming
The alloy 276 is cold-worked under annealed condition, as it has higher work-hardening rate than the austenitic stainless steels.
Hot Forming
The hot-working temperature of this alloy is 870 – 1230°C (1600 – 2250°F), followed by water quenching and heat treatment to ensure maximum corrosion resistance.
Other Designations
Other designations that are equivalent to nickel alloy 276 include the following:
Applications
The following are the list of applications of nickel alloy 276:
-
Chemical processing equipment
-
Bleaching vessels and digesters
-
Waste treatment incinerators
-
Reactor vessels
-
Flue gas desulfurization systems
-
Oil and gas production industry