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Eternal
ASTM A453 Gr.660 forgings (also called A286 alloy, UNS S66286, W.Nr. 1.4980, GH2132, SUH660) are iron-nickel-chromium based, precipitation-hardening austenitic high-temperature alloy forgings. This material is designed for high-temperature and high-pressure fasteners. Its key advantage is that its thermal expansion rate closely matches that of 304/316/321 austenitic stainless steel flanges. When used for a long time below 650°C, it can keep bolt preload and prevent flange leaks caused by thermal mismatch.
Jiangyin Eternal Heavy Industry Co., Ltd. uses a VIM + VAR/ESR double vacuum melting process to make ASTM A453 Gr.660 ingots. Through open die forging, product forms include forged bars, forged rings, valve body forgings, flange blanks, and custom non-standard forgings. Single piece weight ranges from 300 kg to 30,000 kg.
Element | wt% | Role |
Ni | 24.0 – 27.0 | Stabilize the austenitic matrix and provide high-temperature strength |
Cr | 13.5 – 16.0 | Antioxidant and corrosion resistance |
Mo | 1.0 – 1.5 | Solid solution strengthening, enhancing creep strength |
Ti | 1.9 – 2.35 | Eutectic precipitation of γ' phase, main strengthening element |
Al | ≤ 0.35 | Promote the formation of the γ' phase |
V | 0.10 – 0.50 | Refine the grains and enhance the toughness |
B | 0.003 – 0.010 | Strengthening grain boundaries |
C | ≤ 0.08 | — |
Mn | ≤ 2.0 | — |
Si | ≤ 1.0 | — |
P | ≤ 0.03 | — |
S | ≤ 0.015 | — |
Fe | Balance | Base |
Standard | Grade |
ASTM | A453 Grade 660 / A638 Type 660 |
UNS | S66286 |
Commercial | A286 / Alloy 660 |
EN/DIN | W.Nr. 1.4980 / X5NiCrTiMoV26-15 |
AISI | 660 |
JIS | SUH660 |
GB | GH2132 |
Item | ClassA/B/C | ClassD(≤63.5mm) | Standard |
Tensile strength (MPa) | ≥ 895 | ≥ 895 | ASTM E8 |
Yield strength 0.2% (MPa) | ≥ 585 | ≥ 725 | ASTM E8 |
Elongation (%) | ≥ 15 | ≥ 15 | ASTM E8 |
Reduction of area (%) | ≥ 18 | ≥ 18 | ASTM E8 |
Hardness (HBW) | 248 – 321 | 248 – 321 | ASTM E10 |
Impact toughness (J, RT) | ≥ 47 | ≥ 47 | ASTM E23 |
Process | Temperature |
initial forging temperature | 1093 – 1177°C |
final forging temperature | 899 – 927°C |
minimum forging ratio | ≥ 15–20% |
Process | data | cooling |
solution treatment | 900 ± 14°C，keep≥2h | oil |
aging treatment | 720 ± 14°C，keep≥16h | air |
Optional surface treatments and finishing: The forgings can offer various surface conditions such as black skin, rough machining, and fine machining (mirror finish rods), and support the customization of machined and polished parts for delivery.
ASTM A453 Gr.660 forged parts are specifically designed for high-temperature and high-pressure fasteners and load-bearing structural components.
Lag bolts and studs of the steam turbine cylinder body joint surface
Fasteners for the exhaust cylinder of the gas turbine
Lag bolts of the pressure vessel of nuclear power (PWR)
Boiler pipeline connection components
Hydrogenation reactor flange bolts
Ethylene cracking furnace tube flange
High-temperature valve bonnet bolts
High-temperature flange connection of pressure vessel
Aircraft engine structural connection components
Turbo casing fasteners
Compressor disk bolts
Type | Reference price |
forged bar | 3-10 USD /kg |
Brightness rod | 10-25 USD/kg |
Hex bar | 7-10 USD/kg |
Customized bar | 10-50 USD/kg |
Is ASTM A453 Gr.660 the same material as A286?
Yes. ASTM A453 Gr.660 is a fastener standard based on A-286 alloy (UNS S66286), and the chemical composition of the two is exactly the same. A286 is the common commercial name, while Gr.660 is the grade in the ASTM A453 standard.
What is the maximum service temperature of Gr.660?
The recommended upper limit for long-term continuous service is 650°C. The ASTM standard specifies a design service temperature limit of about 700°C. Above this temperature, microstructural stability and creep properties need to be evaluated.
What inspection reports can you provide?
We can provide EN 10204-3.1 / 3.2 certificates, chemical composition analysis reports, mechanical property test reports, ultrasonic testing (UT) reports, metallographic structure reports, and more. We also support third-party inspection (SGS / TÜV / BV).
What is the minimum order quantity? What is the delivery lead time?
For standard forged bars / round bars, the minimum order quantity is 300 kg. Custom forgings can be produced as a single piece. Regular fixed-size products are delivered in 7–15 days. Custom forgings take about 20–35 days, depending on drawing complexity.
