ASTM A573 Grade 65 Carbon Steel
ASTM A573 Grade 65 Carbon Steel - Improved Toughness, High-Strength Structural Plate
ASTM A573/A573M Grade 65 is a structural carbon steel with improved toughness, offering a minimum yield strength of 35 ksi (240 MPa) and tensile strength of 65-85 ksi (450-585 MPa).
Hot rolling, controlled rolling, normalizing (optional), welding, cutting, machining, cold forming
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ASTM A573 Grade 65 Carbon Steel Introduction
ASTM A573/A573M Grade 65 is a hot-rolled structural carbon steel plate designed for improved notch toughness in moderate and low-temperature service. It is classified under the specification "Standard Specification for Structural Carbon Steel Plates of Improved Toughness." The steel combines good weldability, formability, and consistent mechanical properties, making it suitable for bridges, buildings, railway cars, and heavy construction equipment.
- Enhanced toughness compared to ordinary carbon steel grades like A36
- Minimum yield strength 35 ksi (240 MPa); tensile strength 65–85 ksi (450–585 MPa)
- Supplied in as-rolled or normalized condition; optional Charpy V-notch impact testing at -50°F (-46°C)
- Fully killed, fine-grain practice ensures uniformity
- Available in plates, coils, and cut-to-length sheets
Typical applications demand reliable low-temperature performance without the need for full alloy treatment.
ASTM A573 Grade 65 Carbon Steel Chemical Composition
Heat analysis according to ASTM A573/A573M. Values are maximum unless a range is given. Copper is not a mandatory element but may be specified when improved atmospheric corrosion resistance is desired. Residual elements are controlled to ensure weldability and toughness.
| Element | Standard Value (wt. %) | Remarks |
|---|---|---|
| Carbon, C | 0.26 max | |
| Manganese, Mn | 0.85–1.20 | For thickness ≤ 1.5 in. (40 mm) |
| Phosphorus, P | 0.035 max | |
| Sulfur, S | 0.04 max | |
| Silicon, Si | 0.15–0.40 | Typical for killed steel |
| Copper, Cu | 0.20 min (if specified) | Only when copper steel is ordered; otherwise residual ≤ 0.35% |
ASTM A573 Grade 65 Carbon Steel Thermal and Electrical Physical Properties
These values are typical for carbon steel of this composition at room temperature unless otherwise noted. They are not part of the standard specification but provide useful design guidance.
| Property | Typical Value | Unit | Test Condition / Temperature |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20°C |
| Elastic Modulus (E) | 200 | GPa | 20°C |
| Shear Modulus (G) | 77 | GPa | 20°C |
| Poisson's Ratio (ν) | 0.3 | - | 20°C |
| Thermal Expansion Coefficient (α) | 11.7 | ×10⁻⁶ /K | 20–100°C |
| Thermal Conductivity (λ) | 52 | W/m·K | 100°C |
| Specific Heat Capacity | 486 | J/kg·K | 20°C |
| Electrical Resistivity (ρₑ) | 0.16 | µΩ·m | 20°C |
ASTM A573 Grade 65 Carbon Steel Mechanical Properties
Tensile properties in longitudinal direction for plates ≤ 1.5 in. (40 mm) thickness. Elongation requirements vary with plate thickness. Bending cold tests are performed at ambient temperature to 180° without cracking. Charpy V-notch impact testing is optional; when specified, the values below apply.
| Property | Standard Requirement | Unit | Test Condition / Remarks |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 35 (240) | ksi (MPa) | 0.2% offset, for thickness ≤ 1.5 in. (40 mm) |
| Tensile Strength (Rm) | 65–85 (450–585) | ksi (MPa) | |
| Elongation in 8 in. (200 mm) | ≥ 20 | % | For thickness ≤ 3/4 in. (20 mm), longitudinal |
| Elongation in 8 in. (200 mm) | ≥ 18 | % | For thickness > 3/4 in. to 1.5 in. (20–40 mm), longitudinal |
| Elongation in 2 in. (50 mm) | ≥ 23 | % | For thickness ≤ 3/4 in. (20 mm), longitudinal |
| Elongation in 2 in. (50 mm) | ≥ 22 | % | For thickness > 3/4 in. to 1.5 in. (20–40 mm), longitudinal |
| Bend Test (Cold) | No cracks or defects | - | Bend diameter = 2× thickness, 180° bend |
| Charpy Impact Energy (CVN) | ≥ 15 ft·lbf (20 J) | ft·lbf (J) | Longitudinal, at -50°F (-46°C) – when specified |
| Charpy Impact Energy (CVN) | ≥ 15 ft·lbf (20 J) | ft·lbf (J) | At -60°F (-51°C) may also be agreed |
ASTM A573 Grade 65 Carbon Steel Completely Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| European Union | EN 10025-2 | S275JR / S275J0 / S275J2 | Yield 275 MPa; toughness levels J0 (0°C) and J2 (-20°C) comparable to A573 Gr.65 with impact requirement |
| Japan | JIS G3106 | SM400A / SM400B | SM400B has Charpy at 0°C; mechanical properties similar but toughness not as low as -46°C |
| China | GB/T 700 | Q235B / Q235C / Q235D | Q235D with -20°C impact is closest; yield ~235 MPa |
| International | ISO 630-2 | S235JR / S235J0 | Closest to ordinary structural steel; toughness levels not matching -46°C unless specified |
ASTM A573 Grade 65 Carbon Steel Application Introduction
ASTM A573 Grade 65 is intended for structural applications where improved notch toughness at moderate to low temperatures is required. It bridges the gap between ordinary carbon steel and fully alloyed low‑temperature steels. Typical uses:
Product Applications: Welded plate girders, Stiffened panels and box structures, Railcar underframes and side sills, Bridge diaphragms and stiffeners, Excavator and crane booms, Support bases for heavy equipment
Processed into products: Beams, columns, and truss members, Gusset plates and connection plates, Base plates and bearing plates, Stiffeners and bracing members, Welded‑built‑up sections, Flanges and webs in built‑up girders
Application industries: Bridge construction and retrofitting, Commercial and industrial building structures, Railway cars and transport equipment, Heavy construction machinery, Storage tanks and pressure vessels (with design code approval), Offshore structural components (non‑splash zone)
ASTM A573 Grade 65 Carbon Steel Similar/Comparable Substitution Materials Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A36/A36M | A36 | Higher yield (36 ksi) but no guaranteed toughness; use A573 when low‑temperature service is required |
| USA | ASTM A572/A572M | Grade 50 | Higher strength (50 ksi) but limited toughness; may substitute if strength is primary factor |
| USA | ASTM A283/A283M | Grade D | Similar tensile range but minimal toughness; A573 Grade 65 is superior for low‑temperature applications |
| European Union | EN 10025-2 | S235JR | Lower yield; not suitable for the same low‑temperature toughness |
| European Union | EN 10025-3 | S275N | Normalized, with guaranteed -20°C toughness; can substitute if additional processing is acceptable |
Notes:
Supplementary requirements in ASTM A573/A573M include optional Charpy impact testing at -50°F (-46°C) or lower, ultrasonic examination, and limited chemistry adjustments for improved atmospheric corrosion resistance (copper addition). When ordering, the purchaser should specify the plate thickness, width, condition, and any supplementary requirements. The steel may be supplied in coils subject to the same mechanical and chemical limits after uncoiling and flattening.
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