Jul 25 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
Machinability
Welding
Heat Treatment
Forging
Hardening
Other Designations
Applications
Introduction
Pyromet alloy 680 is a nonmagnetic, heat and corrosion resistant, nickel-base alloy that exhibits excellent high temperature strength and oxidation resistance. It is resistant to stress-corrosion cracking. It is a solid solution strengthened alloy and develops optimum mechanical properties through a simple heat treatment.
The following section will provide an overview of Pyromet alloy 680.
Chemical Composition
The chemical composition of Pyromet alloy 680 is outlined in the following table.
|
Element |
Content (%) |
|
Chromium, Cr |
20.5-23 |
|
Iron, Fe |
17-20 |
|
Molybdenum, Mo |
8-10 |
|
Manganese, Mn |
1 |
|
Silicon, Si |
1 |
|
Aluminum, Al |
0.5 |
|
Cobalt, Co |
0.5-2.5 |
|
Copper, Cu |
0.5 |
|
Tungsten, W |
0.2-1 |
|
Titanium, Ti |
0.15 |
|
Carbon, C |
0.05-0.15 |
|
Phosphorus, P |
0.04 |
|
Sulfur, S |
0.03 |
|
Nickel, Ni |
Balance |
Physical Properties
The following table shows the physical properties of Pyromet alloy 680.
|
Properties |
Metric |
Imperial |
|
Density |
8.22 g/cm3 |
0.297 lb/in3 |
|
Melting point |
1260-1354°C |
2300-2470°F |
Mechanical Properties
The mechanical properties of Pyromet alloy 680 are displayed in the following table.
|
Properties |
Metric |
Imperial |
|
Tensile strength (solution annealed) |
114 MPa |
16534 psi |
|
Yield strength (solution annealed) |
70 MPa |
10153 psi |
|
Elongation at break (solution annealed) |
43% |
43% |
Thermal Properties
The thermal properties of Pyromet alloy 680 are given in the following table
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@26-38°C/79-200°F) |
13.86 µm/m°C |
7.7 µin/in°F |
|
Thermal conductivity |
9.06 W/mK |
62.8 BTU.in/hrft².°F |
Fabrication and Heat Treatment
Machinability
Pyromet alloy 680 is machinable by conventional means and is similar to machining of the austenitic stainless steels.
Welding
The alloy can be welded using conventional processes such as shielded metal arc, resistance welding, and tungsten inert gas welding techniques.
Heat Treatment
The alloy is heat treated at (2150°F) and then rapidly cooled.
Forging
Forging of Pyromet alloy 680 can be carried out using conventional methods.
Hardening
The alloy can be hardened by cold working.
Other Designations
Other designations that are equivalent to Pyromet alloy 680 include the following:
|
AISI 680 |
ASTM B435 |
GE B50A436 |
|
AMS 5536 |
ASTM B572 |
GE B50A463 |
|
AMS 5587 |
ASTM B619 |
GE B50T83A |
|
AMS 5588 |
ASTM B622 |
GE B50TF24 |
|
AMS 5754 |
ASTM B626 |
GE B50TF31 |
|
AMS 5798 |
DIN 2.4603 |
GE B50TF25 |
|
ASTM B366 |
DIN 2.4665 |
PWA 1038 |
Applications
The following are the list of applications of Pyromet alloy 680:
-
Petrochemical process equipment
-
Gas turbines
-
Afterburner components
-
Chemical industry.