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Introduction: Ever Wonder How Jet Engines Handle Extreme Heat? Or What Keeps Nuts and Bolts Strong in Tough Conditions?
If you’re involved with high-stress, high-temperature engineering, you’ve probably come across A286. It’s a superalloy that’s a bit of a workhorse. I’m going to break down what A286 is, why it’s so useful, and how we get it ready for action.
What Exactly is A286 Superalloy?
A286 is a high-temperature superalloy based on iron, chromium, and nickel. We add other bits like molybdenum, titanium, aluminium, vanadium, and a tiny bit of boron to make it even stronger. Think of it as a recipe where each ingredient boosts specific characteristics. You might hear it called GH2132 in China or ZbNCT25 in France – it’s the same stuff, just different labels!
It’s worth noting that the exact makeup of A286, plus how strong it is and how we treat it, can change a bit depending on the specific standard it needs to meet.
A286 Chemical Composition
Here’s a quick look at what goes into making A286 (according to the SAE J467b standard):
Component | C | Si | Mn | Cr | Ni | Mo | Ti | V | B | Al | Other |
Nominal | 0.05 | 0.4 | 1.4 | 15 | 26 | 1.3 | 2.15 | 0.3 | 0.004 | 0.2 | Fe: Bal |
Why is A286 So Strong? (A286 Mechanical Properties)
A286 starts as a structure called austenite. To make it tougher, we put it through a process where tiny compounds (called y’ phase Ni3(Ti,Al)) form within it. This is like adding tiny reinforcements. The result? A286 becomes really good at resisting stress, staying hard even when it’s hot, and not gradually stretching out under load (that’s called creep).
Here’s a table showing how strong A286 can be:
Temperature (°C) | Heat Treatment or Condition | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Reduction of Area (%) | Hardness (HBW) | Impact Energy (KV2/J) |
Room Temp (21°C) | 982°C + 718°C | 1000 | 655 | 24 | 45 | HRC 26 | 87 |
Room Temp (21°C) | 899°C + 718°C | 1082 | 703 | 25 | 46 | 302 |
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649°C | 982°C + 718°C | 710 | 607 | 13 | 14 |
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649°C | 899°C + 718°C, 718°C | 752 | 621 | 18 | 25 |
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A286 Physical Properties
Here’s how A286 behaves physically:
Linear Expansion Coefficient (in./in./F×10−6) | Density (lb/in3) | Specific Gravity | Melting Point (F) |
70F 9.17 | 0.286 | 7.94 |
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70F 9.35 |
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70F 9.47 |
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70F 9.64 |
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70F 9.78 |
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70F 9.88 |
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70F 10.32 |
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70F 2600 |
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Elastic Modulus (E) (106 psi) | Shear Modulus (G) (105 psi) | Poisson’s Ratio | Thermal Conductivity | Resistivity |
F | E | F | G | F |
70 | 29.1 | 1500 | 18.7 | 70 |
A286 Heat Treatment
To get A286 to perform its best, we need to treat it with heat in a specific way. Different standards (like those from AMS) have their own recipes. Here are a few:
Standard | Standard Recommended Heat Treatment System |
AMS | 5726-2006: 982°C±14°C Solution + 649°C-704°C±14°C Aging for no less than 8h |
AMS | 5731-2006: 982°C±14°C Solution + 718°C ± 8°C Aging for no less than 16h |
AMS | 5732-2006: 982°C±14°C Solution + 704°C-760°C Aging for no less than 16h |
AMS | 5734-2006: 899°C±14°C Solution + 718°C±8°C Aging for no less than 16h |
AMS | 5737-2006: 899°C±14°C Solution + 704°C-760°C Aging for no less than 16h |
AMS | 5853-2006: 982°C±14°C Solution 1-2h + 649°C~704°C±14°C Aging for no less than 8h |
Where Do We Use A286? (A286 Applications)
A286 is my go-to when I need a material that stays strong even when it’s hot (up to about 650°C). It’s also easy to work with and weld. This makes it perfect for:
Jet Engines: A286 is often used for parts that have to withstand extreme temperatures and forces, like turbine discs, compressor discs, and rotor blades.
Fasteners: Think nuts, bolts, and rivets. If they need to hold things together in harsh conditions, A286 is a great choice. You’ll often see it specified under standards like AMS5726/5731/5732/5734/5737/5853.
This includes things like 900MPa grade nuts, 1100MPa grade aviation HB bolts, 1300MPa grade NAS high-strength bolts, and test pieces.
How Do We Make A286? (A286 Smelting)
Making high-quality A286 is a multi-step process. We don’t just melt it once and call it a day. Usually, we use two or three melting methods together to get the best results.
Most A286 made in my country goes through:
- Vacuum Induction Melting (VIM):This is where we melt the ingredients in a vacuum. It gives us a lot of control over the chemistry and keeps out unwanted gases and impurities.
- Vacuum Arc Remelting (VAR):This is a second melting process that further cleans up the metal and makes it solidify in a way that gives it even better properties.
A286 FAQs
What’s the main benefit of A286?
It’s incredibly strong at high temperatures and resists creep.
Where is A286 used?
Jet engines and high-strength fasteners are common applications.
Is A286 hard to weld?
No, it has good weldability.
What temperatures can A286 handle?
It’s effective up to around 650°C.
Are there different types of A286?
Yes, there are variations depending on the standard it’s made to (e.g., AMS standards).
Conclusion: Is A286 Right For You?
If you’re dealing with extreme heat and stress, A286 superalloy is definitely worth considering. Its blend of strength, heat resistance, and workability makes it a top choice for demanding applications. Contact us for more details about A286.