Jul 25 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Hot Working
Forging
Cold Working
Annealing
Hardening
Aging
Applications
Introduction
Super alloys are exceptionally strong and lightweight. These alloys display excellent mechanical strength, creep resistance at elevated temperatures, good surface stability, corrosion and oxidation resistance, thus making them capable of surviving in extreme conditions that would basically destroy base metals like aluminum and steel.
Nicrofer 5219 Nb is a high-strength, high-temperature resistant and corrosion resistant nickel-chromium alloy. It is can be used at cryogenic temperatures and also in air up to 704°C (1300°F). This alloy can be readily worked and age-hardened. The following sections will discuss in detail about super alloy Nicrofer 5219 Nb.
Chemical Composition
The chemical composition of Nicrofer 5219 Nb is outlined in the following table.
|
Element |
Content (%) |
|
Nickel, Ni |
50 – 55 |
|
Chromium, Cr |
17 - 21 |
|
Niobium (Nb) |
4.75 - 5.5 |
|
Molybdenum, Mo |
2.8 - 3.3 |
|
Cobalt, Co |
1 max |
|
Titanium, Ti |
0.65 - 1.15 |
|
Silicon, Si |
0.35 max |
|
Manganese, Mn |
0.35 max |
|
Copper, Cu |
0.3 max |
|
Aluminum, Al |
0.2 - 0.8 |
|
Carbon, C |
0.08 max |
|
Phosphorus, P |
0.015 max |
|
Sulfur, S |
0.015 max |
|
Boron, B |
0.006 max |
|
Iron, Fe |
Balance |
Physical Properties
The physical properties of Nicrofer 5219 Nb are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
8 g/cm3 |
0.29 lb/in3 |
|
Melting point |
1326°C |
2420°F |
Thermal Properties
The thermal properties of Nicrofer 5219 Nb are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal conductivity (@20°C/68°F) |
11.1 W/mK |
77 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to Nicrofer 5219 Nb are given below:
|
AMS 5597 |
AMS 5832 |
DIN 2.4688 |
GE B50TF14 |
GE B50TF15 |
|
AMS 5596 |
AMS 5664 |
DIN 2.4668 |
GE B50 TF69 |
PWA 1009 |
|
AMS 5590 |
AMS 5663 |
ASTM B670 |
GE B50 TF14 |
PWA 1010 |
|
AMS 5589 |
AMS 5662 |
ASTM B637 |
GE B14H89 |
PWA 1033 |
|
RBO 170-153 |
SPS M275 |
SPS M637 |
|
|
Fabrication and Heat Treatment
Machinability
Super alloy Nicrofer 5219 Nb can be machined using the common processes applied to iron based alloys. This alloy does work-harden during machining and displays higher strength and "gumminess" unlike steels. It is recommended that heavy duty machining equipment and tooling should be used to reduce chatter or work-hardening of the alloy.
Any commercial coolants can be used during the machining operations; however water-based coolants are recommended for high-speed operations such as milling, turning, or grinding. Similarly, heavy lubricants are ideal for tapping, broaching, drilling, or boring.
Forming
Super alloy Nicrofer 5219 Nb can be formed using any of the conventional methods. Powerful equipment is required to perform forming operations as this alloy is strong.
Welding
Welding of super alloy Nicrofer 5219 Nb can be performed using all the traditional welding methods. Matching alloy filler metal should be used. In case that is not available, it is advised that the nearest alloy closest to the chemical composition be used.
Hot Working
Hot working can be performed in the temperature range of 1121-899°C (2050-1650°F). In case the hot working temperatures fall below 899°C (1650°F), it is essential to reheat the alloy.
Forging
Forging can be performed at temperatures in the range of 1121-927°C (2050-1700°F).
Cold Working
Nicrofer 5219 Nb can be cold formed using all the standard tools.
Annealing
Nicrofer 5219 Nb can be annealed at 1037°C (1900°F) and rapidly air cooled.
Hardening
Super alloy Nicrofer 5219 Nb hardens by cold working and aging heat treatment. Cold working increases both hardness and strength of this alloy.
Aging
For aging super alloy Nicrofer 5219 Nb, the material has to be annealed at 982°C (1800° F) and aged at 718°C (1325°F) for 8 h. Then furnace cooled to 621°C (1150°F) and held at that temperature for 10 h, and finally air cooled. This treatment provides the highest room temperature strength and excellent rupture properties.
Applications
Nicrofer 5219 Nb is widely used in many application areas as listed below:
-
Pump shafts
-
High-strength bolting, springs and fasteners
-
Turbine disk material in aircraft jet engines
-
Drilling equipment in sour oil and gas wells
-
Components in nuclear reactors and space vehicles
-
Gas turbine hot section components and cryogenic storage tanks
-
Highly stressed rotating and static components in gas turbines and rocket engines
-
High-temperature tooling for extrusion of metals such as copper, and for shearing
-
Highly stressed well head and downhole parts in offshore and marine engineering.