ASTM A453 Grade 660 Round Bar
ASTM A453 is the specification for high temperature bolting materials with expansion coefficients comparable to austenitic stainless steels. Grade 660 under this standard is the precipitation hardening iron-base superalloy A286 (UNS S66286), supplied in four heat treatment classes - A, B, C and D - that differ in solution treatment temperature and in the yield strength achieved after ageing.
Nexforge Alloys supplies ASTM A453 Grade 660 round bars specifically prepared for the manufacture of studs, bolts, nuts and washers for valves, flanged joints, turbine casings and pressure vessels working at elevated temperatures. Bars are supplied fully heat treated, hardness checked and marked heat-wise for full traceability.
ASTM A453 Grade 660 Class A, B, C and D round bars for high temperature bolting, 8 mm to 200 mm diameter, ready stock with EN 10204 3.1 certificates.
A453 Grade 660 Round Bar Specification
| Parameter | Details |
|---|---|
| Specification | ASTM A453 / ASME SA453 Grade 660 Class A, Class B, Class C and Class D |
| Alloy | A286, UNS S66286, W.Nr. 1.4980 |
| Size Range | 8 mm to 200 mm diameter |
| Length | 3 to 6 metres random, or cut lengths for stud manufacturing |
| Condition | Solution treated and aged as per the class ordered |
| Surface Finish | Bright peeled / centreless ground |
| Tolerance | h9 / h10 or as specified |
| Testing | Tensile, hardness, stress rupture (Class A/B), chemical analysis, UT on request |
| Certification | EN 10204 3.1; 3.2 with third-party witness available |
Chemical Composition (% by weight)
| Element | C | Mn | Si | P | S | Cr | Ni | Mo | Ti | Al | V | B | Fe |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grade 660 | 0.08 max | 2.00 max | 1.00 max | 0.025 max | 0.025 max | 13.5 - 16.0 | 24.0 - 27.0 | 1.00 - 1.50 | 1.90 - 2.35 | 0.35 max | 0.10 - 0.50 | 0.001 - 0.010 | Balance |
Mechanical Properties
| Class | Solution Treatment | Tensile Strength (min) | 0.2% Yield Strength (min) | Elongation (min) | Reduction of Area (min) | Hardness |
|---|---|---|---|---|---|---|
| Class A | 885 - 915 °C, oil or water quench | 895 MPa (130 ksi) | 585 MPa (85 ksi) | 15 % | 18 % | 24 - 37 HRC |
| Class B | 965 - 995 °C, oil or water quench | 895 MPa (130 ksi) | 585 MPa (85 ksi) | 15 % | 18 % | 24 - 37 HRC |
| Class C | 885 - 915 °C, followed by two-step ageing | 895 MPa (130 ksi) | 725 MPa (105 ksi) | 15 % | 18 % | 24 - 37 HRC |
| Class D | 965 - 995 °C, followed by two-step ageing | 895 MPa (130 ksi) | 725 MPa (105 ksi) | 15 % | 18 % | 24 - 37 HRC |
Values are minimum or typical figures as per the referenced standards and are for guidance only. Please refer to the mill test certificate supplied with the material for actual values.
Key Features
- Bolting grade with controlled hardness and guaranteed stress-rupture properties
- Thermal expansion matched to austenitic stainless steel flanges and casings
- Retains clamping load at temperatures up to 650 °C
- Heat-wise traceability suited to pressure equipment and valve manufacturers
Applications
- Studs, bolts and nuts for high temperature valves and flanged joints
- Turbine casing and steam chest bolting
- Pressure vessel and heat exchanger fasteners
- Fasteners for exhaust systems and turbochargers
- Refinery and petrochemical high temperature bolting