# A-286 Bolts

*UNS S66286 · 1.4980 · GH2132*

**Category:** Iron-Based Superalloy

A-286 (UNS S66286, GH2132, 1.4980) is an iron-based, age-hardenable austenitic bolting grade rated to 650°C and supplied to ASTM A453 Grade 660 and AMS 5732 at 1000 MPa tensile and 690 MPa yield in the aged condition. Strengthening comes from gamma-prime Ni₃(Al,Ti) precipitates, so a286 bolts and a286 fasteners deliver roughly 80% of the strength of Inconel 718 at a fraction of the nickel content, and therefore a fraction of the cost.

A286 hex bolts and a286 stud bolts hold their proof strength to 650°C and resist oxidation and scaling well beyond that, which makes them the default choice for turbocharger, exhaust and hot-bolting hardware where budget matters as much as performance.

We melt A-286 by VIM plus ESR to keep sulphur below 0.010%, which matters because sulphur segregation is the main cause of hot-forging cracks in UNS S66286 bolts and notch sensitivity in 1.4980 bolt stock.

## Standards

- ASTM A453 Grade 660
- AMS 5731
- AMS 5732
- AMS 5734
- UNS S66286
- 1.4980

## Chemical composition (wt%)

| Element | Min | Max |
|---|---|---|
| Fe | Balance | - |
| Ni | 24.0 | 27.0 |
| Cr | 13.5 | 16.0 |
| Mo | 1.00 | 1.50 |
| Ti | 1.90 | 2.35 |
| V | 0.10 | 0.50 |
| Al | - | 0.35 |
| B | 0.001 | 0.010 |
| C | - | 0.08 |
| Mn | - | 2.00 |
| Si | - | 1.00 |
| S | - | 0.030 |
| P | - | 0.025 |

## Mechanical properties

| Condition | Tensile (MPa) | Yield (MPa) | Elongation (%) | Hardness |
|---|---|---|---|---|
| Solution Treated | 895 | 585 | 25 | ≤ 24 HRC |
| AMS 5732 Sol + Aged | 1000 | 690 | 15 | 24-35 HRC |
| AMS 5737 High Strength | 1030 | 725 | 12 | 26-36 HRC |

## Applications

- **Gas Turbines**: A286 bolts for compressor casing bolting, diffuser and combustor hardware operating between 400°C and 650°C.
- **Aircraft Engines**: A286 fasteners for non-rotating engine hardware, brackets and clamps qualified to AMS 5731 / 5732.
- **Turbochargers**: Turbine housing studs and V-band hardware exposed to exhaust gas thermal cycling.
- **Heat Treatment**: Furnace fixtures, basket bolting and jigs that see repeated heating to 650°C without scaling.

## FAQ

### What is the maximum operating temperature of A286 bolts and a286 fasteners?

650°C (1202°F) for load-bearing service. A286 hex bolts and a286 stud bolts survive short excursions to 700°C but the gamma-prime over-ages and proof strength falls sharply above 650°C.

### ASTM A453 Grade 660 vs AMS 5732: which do I need?

ASTM A453 Grade 660 is the pressure-vessel and flange bolting standard (Classes A through D differ in heat treatment and hardness). AMS 5732 is the aerospace bar specification. Chemistry is essentially identical, and the certification path and mechanical minimums differ.

### Is A-286 magnetic?

No. In the properly solution treated and aged condition A-286 is fully austenitic and non-magnetic, with a relative permeability below 1.01. Slight magnetic response indicates cold work or incorrect heat treatment.

### How are A286 bolts heat treated?

Solution treat at 980°C for 1 hour and oil quench, then age at 720°C for 16 hours and air cool. Class D A286 fasteners to ASTM A453 use a 900°C solution treatment for higher notch toughness.