Jul 4 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Other Designations
Fabrication
Machinability
Welding
Forming
Hot working
Cold Working
Annealing
Applications
Introduction
INCOLOY alloys are super alloys that have nickel as the base metal. Apart from nickel, chromium and iron are the other major components of this alloy. Addition of metals such as molybdenum, copper, etc., enhances characteristics such as strength and corrosion resistance.
INCOLOY alloy 27-7MO is an advanced super-austenitic stainless steel containing 7% of molybdenum. When the content of molybdenum is increased the corrosion resistance in many environments is enhanced. The combination of nickel, nitrogen and molybdenum increase the corrosion resistance range to reducing media, pitting, crevice, acids, stress cracking and caustic corrosion. This alloy is also capable of resisting corrosion by sea water and chemicals in the pulp, paper, oil and gas industries. The standard forms in which this alloy is available are plate, sheet, rod, bar, tube and pipe.
This datasheet will look into the chemical composition, properties and applications of INCOLOY 27-7MO.
Chemical Composition
The chemical composition of INCOLOY alloy 27-7MO is given in the following table.
|
Element |
Content (%) |
|
Iron, Fe |
35.54-46.2 |
|
Nickel, Ni |
26-28 |
|
Chromium, Cr |
20.5-23 |
|
Molybdenum, Mo |
6.5-8 |
|
Manganese, Mn |
≤3 |
|
Others |
Remainder |
Physical Properties
The following table discusses the physical properties of INCOLOY alloy 27-7MO.
|
Properties |
Metric |
Imperial |
|
Density |
8.02 gm/cm3 |
0.290 lb/in3 |
Mechanical Properties
The mechanical properties of INCOLOY alloy 27-7MO are tabulated below.
|
Properties |
Metric |
Imperial |
|
Tensile strength(annealed) |
827 MPa |
120 ksi |
|
Yield strength(annealed) |
414 MPa |
60 ksi |
|
Elongation at Break( in 2 in 50 mm) |
50% |
50% |
|
Poissons Ratio |
0.29 |
0.29 |
|
Modulus of Elasticity |
138 GPa |
20000 ksi |
|
Hardness, Rockwell B |
95 |
95 |
|
Hardness, Vickers (0% cold work) |
225 |
225 |
Other Designations
Some of the designations used to denote INCOLOY alloy 27-7MO are listed below:
-
UNS N08926
-
ASTM A 479
-
ASTM A240
-
ASTM A 213
-
ASTM A 249
-
ASTM A312
-
ASTM A182
-
ASME SA 182.
Fabrication
Machinability
Machining characteristics of this INCOLOY alloy 27-7MO is on the same lines as that of other austenitic alloys. This alloy is machined under annealed conditions.
Welding
INCOLOY alloy 27-7MO can be welded by gas metal arc welding, gas tungsten arc welding, shielded arc welding, plasma arc welding and submerged metal arc welding. The filler metal and electrodes are usually made of INCONEL alloy.
Forming
This alloy can be formed under hot or cold conditions.
Hot working
INCOLOY alloy 27-7MO can be hot worked at temperature ranges of 980-1150°C (1800-2100°F).
Cold Working
Cold rolling may be done on the alloy after annealing.
Annealing
INCOLOY alloy 27-7MO should be annealed at temperatures greater than 1121-1175°C (2050- 2150°F).
Applications
The INCOLOY alloy 27-7MO is used in the following applications:
-
Pollution control
-
Power, marine and chemical industries
-
Pulp, paper, oil and gas industries.