AVAILABLE IN MANY FORMS
Future Alloys can provide the Highest Quality Alloy 32-5 / Super Invar materials in many forms including:
Alloy 32-5 / Super Invar Block, Rod, Bar, Strip, Sheet, Plate, Wire, Cube, Crucibles and Ingots.
We can supply be-spoke sizes and our sales team have many years of experience and can offer you technical information and advice for all the materials we deal with.
CUSTOM MACHINING
Do you have a special application for Alloy 32-5 / Super Invar that needs custom machining?
Special cutters, feeds and cutting fluids are essential to complete Super Invar machining without a detrimental effect to the material.
Future alloys have all the experience and equipment necessary to precision machine Super Invar alloys to the highest specifications.
Please be as specific as possible, for example:
“Please quote for 8 off, 30mm diameter Super Invar 32-5 rods, in 1m lengths”
LOW THERMAL EXPANSION
Super Invar Alloy 32-5 is a controlled ultra low expansion alloy which exhibits near zero thermal expansion at room temperature, the lowest of all the “low expansion alloys”, and one half of standard Invar Alloy at ambient temperature. Plus in the 67 to 203°F , -55 to 95°C temperature range its thermal expansion is less than that of standard Invar Alloy.
STANDARDS AND SPECIFICATIONS
The superalloy complies with the following specifications:
AMS I 23011
ASTM-F-1684 CHEM
CHEMICAL COMPOSITION (%)
| NICKEL (NI) | 31.75 |
| CHROMIUM (CR) | 0.03 |
| MANGANESE (MN) | 0.39 |
| SILICON (SI) | 0.09 |
| CARBON (C) | 0.05 |
| ALUMINUM (AL) | 0.07 |
| COBALT (CO) | 5.36 |
| COPPER (CU) | 0.08 |
| SULFUR (S) | 0.01 |
| IRON (FE) | BALANCE |
Name: Super Invar® / Alloy 32-5
Trade Names: Super Invar®
Chemical sign: 64 Fe – 31 Ni – 5 Co
Thermal expansion: 4.5 ppm / °F ( 75 °F to 842 °F), 8 ppm / °C (25 °C to 450 °C)
Thermal conductivity: 0,10 W / cm x °C
Typical linear coefficient of thermal expansion (cm per cm):
0.35 X 10(-6)/ºF(-67 to 203ºF), 0.63 X 10(-6)/ºC(-55 to 95ºC)
Curie Temperature: 535°F, 279°C
Hardness on Rockwell scale: 75 (annealed), 90 (cold worked)
Yield strength: 40 ksi, 276 MPa
Tensile strength: 70 ksi, 483 MPa
Specific gravity: 8.15
Density: 0.294 lb/cu in, 8150 kg/cu m
Modulus of elasticity: 21 x 10(6) psi, 144 x 10(6) MPa
Melting point: 1455 °C , 2650 °F
Poisson’s Ratio: 0.2
Electrical resistivity: 80 micro-ohm-cm,
Elongation: 40% in 2”
Super Invar®, also known as Invar 32-5 and Alloy 32-5 is an austenitic, solid solution alloy with gummy like texture that belongs to the invar family of nickel-iron alloys. There are three types of the alloy available on the market today; standard invar, super invar (invar 32-5) and free machining invar (invar 36). The difference between them is the chemical composition which in turn varies the properties.
Standard Invar is made up mostly by nickel and iron and with a few other elements in small ratios. Super Invar is built up by approximately 32 % nickel, 5% cobalt, and around 63 % iron with small amounts of silicon, carbon, aluminium, sulfur, copper, chromium and manganese.
The low coefficient of thermal expansion (CTE) is the most important characteristic of all invar types and especially of Super Invar®. The CTE of Super Invar® is around one third of the CTE of regular invar and is almost zero after specific heat processing. It is designed to provide minimum thermal expansion at ambient temperatures. This property alone makes it valuable and even more expensive than regular invar. However, the useful range of Super Invar® is limited and valid only over a controlled temperature limit ( -32° to + 275°C ). This is because the material begins to transform from Austenite to Martinsite at temperature below -32°F and its CTE also changes more rapidly than other low expansion metals outside of this temperature range.
Future alloys can advise the suitability of Super Invar® for your application.
The ever growing demand for accurate and advanced processes drives the development in aeronautical and cryogenic engineering for advanced materials such as super invar. The range of applications include various precision parts, optical instruments and electrical devices.
Some of the applications of Super Invar Alloy include:
Precision measuring devices require maintaining extreme accuracy and dimensional characteristics regardless of changes in temperature. Structural component for supports and substrates often contain Super Invar 32-5 to improve stability for precision measurement assemblies in optical and laser systems. It is also useful for glass and quartz assemblies that require low expansion metals for joining and for wave guide tubes.
One unique application of Super Invar is the SST Telescope in Hawaii. At the top of Mauna Kea, the highest shield volcano on the main island, a 33 ton heavy mirror operates as part of a huge optical infrared telescope. This is the biggest on Earth, and it can locate any object larger than a orange from 100 km away. The telescope has 261 load sensors and actuators for precise observations. At the top of these actuators are sleeves, assembled in which are glass disks that can provide the necessary support between the computer controlled system and the mirror. Due to their location, they are permanently exposed to ever changing temperatures, so a material with low thermal expansion is necessary to maximise the system stability. Super Invar was chosen as the material to achieve the strict criteria.