Profile Overview
Our company, established in 2013, is a leading fabrication services provider in industries such as Oil & Gas, Petroleum, Marine, Oilfield, Mining, and Heavy Industry, specifically for pipeline construction and maintenance.
We are an ideal choice for EPC companies and project contractors, specializing in supplying a range of products including Fasteners, Flanges, Gaskets, Fittings, Valves, Pipes and Piping Spare Parts. Our products are API, CE, TUV and ISO certified, widely used on oil rigs, new nuclear power plants, and heavy industries.
Product Description: ASTM A453 Gr.660
ASTM A453 Gr.660 (also known as Alloy 660 or A-286) is a precipitation-hardening austenitic stainless steel offering outstanding high-temperature performance and corrosion resistance.
Chemical composition of ASTM A453 Gr.660
| Alloy | % | Ni | Cr | C | Mo | Mn | Si | S | P | Ti | V | B | Al |
| 660 | Min | 24 | 13.5 | - | 1 | - | - | - | - | 1.9 | 0.10 | 0.001 | - |
| Max | 27 | 16 | 0.08 | 1.5 | 2.0 | 1.0 | 0.03 | 0.04 | 2.35 | 0.50 | 0.01 | 0.35 |
Mechanical Properties
| Class | Tensile strength (MPa) | Yield strength (MPa) | Elongation (%) | Reduction of area (%) | Hardness (HBW) |
| A, B, C | ≥895 | ≥585 | ≥15 | ≥18 | 248-321 |
| D (d ≤ 63.5 mm) | ≥895 | ≥725 | ≥15 | ≥18 | 248-321 |
| D (d > 63.5 mm) | ≥825 | ≥655 | ≥15 | ≥18 | 248-321 |
Heat Treatment:
- Solution treatment: 900 ± 14 °C, hold ≥ 2 h, oil quench.
- Age hardening: 720 ± 14 °C, hold ≥ 16 h, air cool.
Applications & Environments
ASTM A453 Gr.660 is widely used for high-temperature fasteners such as bolts, studs and nuts in gas turbines, PWR nuclear plants, petrochemical pressure vessels, and aero-engine structural joints.
- High temperature & High pressure: Continuous service up to ~700 °C with outstanding oxidation resistance.
- Cryogenic conditions: Retains toughness and strength at -196 °C and below.
- Corrosive media: Resistant to oxidation, stress-corrosion cracking and corrosion fatigue.
Material Alternatives
| Alternative | Characteristics | Suitable Environment | Relative Cost |
| 316L stainless | Good corrosion resistance | Medium/low temperature | Much lower |
| 17-4 PH (630) | Hardenable, moderate strength | Medium temperature | Medium |
| B8 stainless | Conventional bolting grade | ≤600 °C | Lower |
| PTFE-coated | Fluoropolymer coating | Low/medium temperature | Significantly lower |
Frequently Asked Questions
What are the primary benefits of ASTM A453 Gr.660 fasteners?
ASTM A453 Gr.660 (Alloy 660) offers exceptional high-temperature strength, oxidation resistance up to 700°C, and maintains toughness in cryogenic conditions down to -196°C.
In which industries are these high-strength fasteners typically used?
They are widely used in Oil & Gas, Petroleum, Marine, Nuclear Power plants (specifically PWR), and aero-engine structural joints where high pressure and temperature are constant.
What is the standard heat treatment for Gr.660?
The process involves solution treatment at 900 ± 14 °C followed by an oil quench, and age hardening at 720 ± 14 °C for at least 16 hours with air cooling.
Are there more economical alternatives for less severe environments?
Yes, for temperatures below 600°C or moderate corrosive environments, materials like 316L stainless, 17-4 PH, or B8 stainless are cost-effective alternatives. PTFE-coated alloy steel is also an option for structural needs.
What certifications do your industrial products carry?
All core products, including fasteners and valves, are API, CE, TUV, and ISO certified to ensure compliance with global heavy industry standards.
Can you assist in selecting the right material for specific operating conditions?
Absolutely. By providing operating temperature, pressure, and the medium involved, technical evaluations can be performed to determine the most appropriate and cost-effective material choice.
VLC Part
