Jul 4 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Other Designations
Fabrication
Machinability
Welding
Hot working
Annealing
Applications
Introduction
INCOLOY alloys are super alloys that have nickel as the base metal. These alloys have nickel-chromium-iron as the primary constituents. By varying the other elements, these alloys can be designed to resist attack from specific chemical reagents. These alloys exhibit high strength even at high temperatures.
INCOLOY alloy 25-6HN is also known as super-austenitic stainless steel. This alloy contains a higher content of molybdenum and nitrogen. These additions enhance the thermal stability and corrosion resistance of the alloy. Among super austenitic stainless steels, INCOLOY alloy 25-6HN offers higher degree of corrosion resistance and strength.
This datasheet will look into the chemical composition, properties and applications of INCOLOY 25-6HN.
Chemical Composition
The chemical composition of INCOLOY alloy 25-6HN is given in the following table.
|
Element |
Content (%) |
|
Iron, Fe |
41.3 |
|
Nickel, Ni |
24.3 |
|
Chromium, Cr |
20.6 |
|
Molybdenum, Mo |
6.3 |
|
Others |
Remainder |
Physical Properties
The following table discusses the physical properties of INCOLOY alloy 25-6HN.
|
Properties |
Metric |
Imperial |
|
Density |
8.02 gm/cm3 |
0.290 lb/in3 |
Mechanical Properties
The mechanical properties of INCOLOY alloy 25-6HN are tabulated below.
|
Properties |
Metric |
Imperial |
|
Tensile strength(annealed) |
552 MPa |
80 ksi |
|
Yield strength(annealed) |
276 MPa |
40 ksi |
|
Elongation at Break |
45% |
45% |
|
Hardness, Rockwell B |
90 |
90 |
Other Designations
Some of the designations used to denote INCOLOY alloy 25-6HN are listed below:
|
UNS N08367 |
ASTM B 688 |
ASTM B 691 |
ASTM B 564 |
ASTM B 472 |
|
ASTM B 676 |
ASTM B 675 |
ASTM B 804 |
ASTM B 366 |
ASTM B 462 |
|
ASTM A240 |
|
|
|
|
Fabrication
Machinability
Machining of INCOLOY alloy 25-6HN should be done at a slightly lower speed when compared to 316 stainless steel, as it has a high strength.
Welding
INCOLOY alloy 25-6HN can be welded by shielded metal arc welding, gas tungsten arc welding, submerged arc welding, plasma arc welding and gas metal arc welding. The filler metal and electrodes are usually made of INCONEL alloy.
Hot working
INCOLOY alloy 25-6HN can be hot worked at temperature ranges of 982-1232°C (1800-2250°F).
Annealing
INCOLOY alloy 25-6HN should be annealed at temperatures greater than 1121°C (2050°F).
Applications
The INCOLOY alloy 25-6HN is used in the following applications:
-
Welded tubes for chemical processing plants
-
Tubes for heat exchangers
-
Marine applications
-
In desalination and flue gas desulfurization equipment
-
Reaction vessels for pharmaceutical vessels.