ASTM A453 Grade 660 Cl.A — Chemical Composition & Mechanical Properties
ASTM A453 Grade 660 Cl.A is a bolting & nut grades grade for high-temperature bolting (UNS S66286, EN / W.Nr 1.4980). It is also known as A-286. This sheet summarises its chemical composition limits, minimum mechanical properties, heat treatment and typical service. Teshi Group manufactures stud bolts and nuts in this grade.
ASTM A453 Grade 660 Cl.A at a glance
| Specification | ASTM A453 Grade 660 Cl.A |
|---|---|
| Material family | Bolting & nut grades |
| Product form | High-temperature bolting |
| UNS number | S66286 |
| EN / W.Nr equivalent | 1.4980 |
| Also known as | A-286 |
| Document | TG-MG-126 · Rev. 1 · October 2026 |
Typical service
High-temperature bolting for turbines, valves and process plant
Heat treatment
Solution treated 900 ± 14 °C (2 h min), liquid quenched; precipitation hardened 720 ± 14 °C for 16 h, air cooled
Chemical composition of ASTM A453 Grade 660 Cl.A (weight %)
Other elements and limits: Ti 1.90–2.35; V 0.10–0.50; Al 0.35 max; B 0.001–0.010
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Tensile strength, min | 895 MPa |
|---|---|
| Yield strength (0.2 % offset), min | 585 MPa |
| Elongation, min | 15 % |
| Hardness | 248–341 HBW |
About bolting & nut grades
Flange bolting is specified as a stud-bolt grade plus a nut grade. ASTM A193 covers high-temperature bolting (B7, B7M, B16, B8, B8M), A320 covers low-temperature bolting (L7, L7M, L43, B8 classes), A453 covers high-strength austenitic bolting (Grade 660), and A194 covers the nuts (2H, 2HM, 4, 7, 8, 8M).
Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.
International equivalents of ASTM A453 Grade 660 Cl.A
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — ASTM / ASME | ASTM A453 Grade 660 Cl.A · ASME SA-453 Grade 660 Cl.A |
| USA — UNS | S66286 |
| Europe — EN designation | X6NiCrTiMoVB25-15-2 |
| Europe — W.Nr | 1.4980 |
| Japan — JIS | SUH660 |
| China — GB / NB | GH2132 (GB/T 14992) |
| China — old GB designation | 0Cr15Ni25Ti2MoAlVB |
Equivalents are the nearest commonly cited grades. Chemistry, mechanical properties and testing differ between standards — compare them before substituting one for another.
Standards for ASTM A453 Grade 660 Cl.A
All material standardsFAQ
ASTM A453 Grade 660 Cl.A: common questions
What is the minimum yield strength of ASTM A453 Grade 660 Cl.A?
585 MPa, with a minimum tensile strength of 895 MPa.
What is the carbon content of ASTM A453 Grade 660 Cl.A?
0.08 max %.
What is the UNS number and EN equivalent of ASTM A453 Grade 660 Cl.A?
UNS S66286; the nearest European designation is W.Nr 1.4980. Equivalents are close but not identical — check the specification if substituting.
How is ASTM A453 Grade 660 Cl.A heat treated?
Solution treated 900 ± 14 °C (2 h min), liquid quenched; precipitation hardened 720 ± 14 °C for 16 h, air cooled.
What is the Chinese (GB) equivalent of ASTM A453 Grade 660 Cl.A?
The nearest Chinese equivalent is GH2132 (GB/T 14992), formerly 0Cr15Ni25Ti2MoAlVB. Equivalents are close but not identical — compare chemistry and properties before substituting.
What is the JIS equivalent of ASTM A453 Grade 660 Cl.A?
The nearest Japanese (JIS) equivalent is SUH660.
Does Teshi Group supply ASTM A453 Grade 660 Cl.A?
Teshi Group manufactures stud bolts and nuts in this grade. Send your size, rating and quantity to info@teshigroup.com for a quotation with EN 10204 3.1 certificates.
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