Super Alloy Altemp 286 (UNS S66286)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
     Machinability
     Forming
     Forging
     Welding
     Annealing
     Cold Working
     Aging
Applications

Introduction

Super alloy Altemp 286 is an iron-based alloy that can be used for both high and low temperature applications. For example it can be used for applications requiring high strength and corrosion resistance up to 704°C (1299°F) and for lower stress applications at high temperatures.

It can be applied in low temperature applications that require a ductile, non-magnetic high strength material at temperatures ranging from above room temperature down to -196°C (321°F).

Altemp 286 is a versatile material that can also be used for medium corrosion applications in aqueous solutions. This super alloy can be produced by AOD refining or vacuum induction melting.

The following sections will discuss super alloy Altemp 286 in further detail.

Chemical Composition

The chemical composition of Altemp 286 is outlined in the following table.

Element Content (%)
Iron, Fe 56
Nickel, Ni 25
Chromium, Cr 14.5
Molybdenum, Mo 1.25
Titanium, Ti 2.1
Vanadium, V 0.3
Manganese, Mn 0.2
Silicon, Si 0.2
Aluminum, Al 0.15
Carbon, C 0.04
Phosphorus, P 0.015
Sulfur, S 0.0020
Boron, B 0.006

Physical Properties

The physical properties of Altemp 286 are tabulated below.

Properties Metric Imperial
Density 7.92 g/cm3 0.286 lb/in3
Melting point 1370-1430°C 2500-2610°F

Mechanical Properties

The following table shows mechanical properties of Altemp 286.

Properties Metric Imperial
Tensile strength 620 MPa 89900 psi
Yield strength 275 MPA 39900 ksi
Poisson’s ratio 0.3 0.3
Elastic modulus 201 GPa 29200 ksi
Elongation at break 40% 40%
Hardness, Rockwell B 85 85

Thermal Properties

The thermal properties of Altemp 286 are tabulated below.

Properties Metric Imperial
Thermal expansion co-efficient (at 20-100°C/68-212°F) 16.5 µm/m°C 9.17 µin/in°F
Thermal conductivity 15.1 W/mK 105 BTU in/hr.ft².°F

Other Designations

Equivalent materials to Altemp 286 are tabulated below:

AISI 662 AMS 5525 AMS 5731 AMS 5732
AISI 660 AMS 5726 AMS 5734 AMS 5737
AMS 5853 AMS 5858 AMS 5895 DIN 1.4943
ASTM A453 Grade 660 ASTM A638 Grade 660 GE B50T1181 GE B50T12
SPS M250 AMS 5804 AMS 5805 DIN 1.4944
GE B50T81      

Fabrication and Heat Treatment

Machinability

Altemp 286 can be machined using all the traditional processes. Turning, drilling, and milling can be performed on this alloy.

Forming

Altemp 286 is readily formable.

Forging

Light forging can be performed at 871-1010°C (1600-1850°F), while heavy forging can be performed at 1010-1204°C (1850-2200°F).

Welding

Welding processes of Altemp 286 is the same as that followed for stainless steel. This alloy does not require preheating or post-welding heat treatment.

Annealing

Annealing can be performed at 790°C (1450°F), followed by air cooling. Altemp 286 can be solution annealed at 982°C (1800°F) and oil quenched, which should be followed by holding at 718°C (1325°F) for 16 h and then air cooled. This heat treatment helps to strengthen the alloy.

Cold Working

Altemp 286 can be cold worked in the same manner as austenitic 300 series stainless steels.

Aging

Aging of Altemp 286 can be performed at 718°C (1325°F) for 16 h followed by air cooling. It is recommended that aging be performed after a solution heat treatment at 982°C (1800°F).

Applications

Altemp 286 can be used at 815°C (1500°F) for continuous service in oxidizing environments.

Altemp 286 can be used in the manufacture of the following:

  • Gas turbine forgings
  • Jet engine nacelles, parts, and fasteners.

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