AMS 5731, A286 Bar, Forging, Tubing and Rings Solution-Treated
AMS 5731 is the SAE Aerospace Material Specification covering A286 (UNS S66286) bar, forging, tubing, and rings in solution-treated condition at 1800 °F (982 °C). Used as raw stock when downstream aging is performed by the customer (typically after machining to final dimension). AMS 5731 is the canonical sol-treated A286 bar spec, the chemistry is identical to AMS 5732 / 5737 but the heat-treatment is sol-treatment-only, leaving aging for the downstream user. Distinguished from AMS 5732 (sol + aged from mill) and AMS 5737 (precision sol + aged) by aging condition. See parent A286 AMS specifications hub, related A286 round bar, forged bar, and the canonical A286 chemical composition.
AMS 5731 covers A286 bar, forging, tubing, and rings in solution-treated condition. Material is VIM-VAR melted, hot-worked to the required form, solution-treated 1800 °F (982 °C) per the spec, oil-quenched. Bar tolerance per AMS 5731 dimensional table; forgings per drawing. Hardness 24-28 HRC after sol-treatment. Customer performs aging (typically 1325 °F × 16 hours) after machining to final dimension. Used as raw stock for downstream cold-heading, machining, and forging operations.
A286 Chemical Composition (UNS S66286)
Element
Min %
Max %
Notes
Iron (Fe)
Balance
Balance
~53 % typical
Nickel (Ni)
24.0
27.0
Solid-solution stabilizer
Chromium (Cr)
13.5
16.0
Corrosion + oxidation resistance
Titanium (Ti)
1.90
2.35
Gamma-prime former (Ni3Ti)
Molybdenum (Mo)
1.00
1.50
Solid-solution strengthener
Vanadium (V)
0.10
0.50
Carbide stabilizer
Aluminium (Al)
0
0.35
Gamma-prime former (Ni3Al)
Boron (B)
0.001
0.010
Grain-boundary strengthening
Carbon (C)
0
0.08
Per ASTM A453
Manganese (Mn)
0
2.00
Per ASTM A453
Silicon (Si)
0
1.00
Per ASTM A453
Phosphorus (P)
0
0.025
Trace impurity
Sulphur (S)
0
0.015
Trace impurity
AMS 5731, A286 Bar, Forging, Tubing and Rings Solution-Treated, Spec Requirements
Property
AMS 5731 requirement
Notes
Form
Bar, forging, tubing, rings
Wide form coverage
Heat treatment
Solution-treated 1800 °F (982 °C)
Aging done downstream by customer
Tensile strength (sol-treated)
Per spec, typically 670 MPa
Customer ages to develop full strength
Yield strength (sol-treated)
Per spec, typically 380 MPa
Customer ages to develop full yield
Hardness (sol-treated)
24-28 HRC
Soft for machinability
Hardness (post-aging by customer)
29-32 HRC
Customer measures after aging
Surface finish
Pickled
No mill scale
Magnetic permeability
< 1.005
Per ASTM A342
When to Specify AMS 5731, A286 Bar, Forging, Tubing and Rings Solution-Treated
Cold-heading / fastener manufacture: AMS 5731 sol-treated bar feeds cold-heading into hex bolts, SHCS, hex nuts with downstream aging.
Machining sol-treated for ease: AMS 5731 soft sol-treated condition is easier to machine than aged AMS 5732, for complex machined parts, machine in sol-treated state then age.
Forging blanks: AMS 5731 bar / forging blanks for downstream closed-die forging into A286 forgings, A286 flanges.
Pre-aged bar alternative: For aged bar ready for use, specify AMS 5732 or AMS 5737 instead.
Industrial bar substitute:ASTM B637 covers similar sol-treated bar for non-aerospace industrial applications.
AMS 5731, A286 Bar, Forging, Tubing and Rings Solution-Treated, Frequently Asked Questions
What is AMS 5731?
SAE / AMS spec covering A286 (UNS S66286) bar, forging, tubing, and rings in solution-treated condition (1800 °F sol). Customer performs aging downstream, typically after machining to final dimension.
AMS 5731 vs AMS 5732, which to specify?
AMS 5731: sol-treated only, customer ages downstream. AMS 5732: sol-treated AND aged from mill, ready for use. Choose AMS 5731 when aging timing is critical to dimensional stability (e.g., precision machined parts where aging after final geometry); AMS 5732 for direct use without further heat treatment.
Is AMS 5731 cheaper than AMS 5732?
Slightly, AMS 5731 omits the aging step at the mill, saving 16 hours of furnace time and electricity. Typical 5-10 % cost savings vs AMS 5732. Customer must perform aging downstream, adding back the cost on the customer side.
What's the heat-treatment temperature for AMS 5731?
Solution-treatment 1800 °F (982 °C) for 1 hour per inch of section, oil-quench. NO aging performed at the mill, aging is done downstream at 1325 °F (718 °C) for 16 hours.
Can AMS 5731 bar be used directly without aging?
NO, sol-treated condition has only ~380 MPa yield (vs 655 MPa aged). Must be aged downstream to develop full A286 mechanical properties (130 ksi tensile / 95 ksi yield). For direct use, specify AMS 5732.
Is AMS 5731 the same as ASTM B637?
Different aerospace vs industrial scope. Chemistry is identical (UNS S66286). AMS 5731 has aerospace AS9100D AQMS implications; ASTM B637 is industrial. For ASME pressure-vessel applications, ASTM B637 is more commonly cited.
What's the lead time on AMS 5731 bar?
Standard sizes 5-50 mm: 4-6 weeks from heat release (no aging step). Larger sizes 50-200 mm: 6-10 weeks. Customer downstream aging adds 1-3 days plus cool-down.
Is AMS 5731 magnetic?
No. Magnetic permeability < 1.005 verified per ASTM A342. Compatible with non-magnetic instrumentation, MRI, and aerospace electromagnetic-sensitive applications.
Can AMS 5731 be NACE MR0175 compliant?
Yes, when supplied with hardness ≤ HRC 35 (HV ≤ 327) per NACE MR0175 / ISO 15156-3 for sour-service. The sol-treated condition is below this hardness; downstream aging may push hardness above HRC 35, verify after aging.
Mechanical Properties per This Spec
Property
Min value (sol-treated)
After customer aging
Tensile strength (MPa)
≥ 670
≥ 895
Yield strength 0.2 % (MPa)
≥ 380
≥ 585
Hardness HRC
24-28
29-32
A286 Products Manufactured per This Spec
TorqBolt manufactures the following A286 products to this specification:
