Jul 10 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Heat Treatment
Forging
Welding
Annealing
Hot Working
Cold Working
Applications
Introduction
Super alloy HAYNES 625 is a nickel-chromium-molybdenum wrought alloy. It is an excellent general purpose material that is ideal for high temperature use in high strength, oxidation problem applications. HAYNES 625 also has excellent corrosion resistance to several acids and resists stress-corrosion cracking and intergranular attack. It can be used in short term applications at temperatures of up to 815°C (1500°F) as well.
The following sections will discuss in detail about super alloy HAYNES 625.
Chemical Composition
The chemical composition of HAYNES 625 is outlined in the following table.
|
Element |
Content (%) |
|
Nickel, Ni |
62 |
|
Chromium, Cr |
21 |
|
Molybdenum, Mo |
9 |
|
Iron, Fe |
≤ 5 |
|
Tantalum, Ta |
3.7 |
|
Niobium, Nb |
3.7 |
|
Cobalt, Co |
≤ 1 |
|
Manganese, Mn |
≤ 0.50 |
|
Silicon, Si |
≤ 0.50 |
|
Titanium, Ti |
≤ 0.40 |
|
Aluminum, Al |
≤ 0.40 |
|
Carbon, C |
≤ 0.10 |
Physical Properties
The physical properties of HAYNES 625 are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
8.44 g/cm3 |
0.305 lb/in3 |
|
Melting point |
1290 - 1350°C |
2350 - 2460°F |
Mechanical Properties
The following table shows mechanical properties of HAYNES 625.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
915 MPa |
133000 psi |
|
Yield strength |
425 MPa |
61600 psi |
|
Elastic modulus |
208 GPa |
30200 ksi |
|
Elongation at break |
46% |
46% |
Thermal Properties
The thermal properties of HAYNES 625 are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@25-200°C/77-392°F) |
12.8 µm/m°C |
7.11 µin/in°F |
|
Thermal conductivity |
9.80 W/mK |
68 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to HAYNES 625 are tabulated below:
|
AMS 5599 |
AMS 5837 |
AMS 5879 |
ASTM B443 |
ASTM B444 |
|
AMS 5581 |
AMS 5666 |
ASTM B366 |
ASTM B446 |
ASTM B704 |
|
ASTM B705 |
DIN 2.4856 |
GE B50TF133 |
MIL E-21562 (RN625) |
Fabrication and Heat Treatment
Machinability
HAYNES 625 can be machined using conventional processes. This alloy tends to work harden ahead of cutting, and hence rigid tooling is required to prevent chatter and work hardening.
Forming
HAYNES 625 can be cold formed using conventional processes and tooling.
Heat Treatment
HAYNES 625 can be heat treated in the solution annealed condition at 1177°C (2150°F) for a specific amount of time depending upon the section thickness of the material. This process has to be followed by annealing the alloy and air cooling.
Forging
Hot forging can be done by heating the material to 1149-1176°C (2100-2150°F). Heating should not exceed 1176°C (2150°F). It is recommended that heavy forging be performed down to a temperature of 1010°C (1850°F) while light forging down to 926°C (1700°F).
Welding
Welding of HAYNES 625 can be performed using all the traditional welding methods. It is recommended that a matching alloy filler metal be used.
Annealing
Annealing can be performed at 982-1093°C (1800-2000°F) and air cooled. Stress relief of cold worked parts can be performed at 593-760°C (1100-1400°F).
Hot Working
Hot working can be performed by heating the alloy to 1177°C (2150°F). As this alloy possesses good strength at high temperatures, it tends to resist hot deformation and hence powerful tools are required.
Cold Working
HAYNES 625 can be cold formed using the traditional methods and tooling.
Applications
HAYNES 625 is used in high temperature applications such as heat exchangers and gas turbine components. This alooy’s good corrosion resistance makes it ideal for use in wet scrubbers and certain acid process equipment.
HAYNES 625 is commonly used in the following industries:
-
Aerospace industry
-
Chemical process industry
-
Power industry.