ASTM A514/A514M covers quenched and tempered high-strength low-alloy (HSLA) structural steel plate intended for welded structures where a combination of high yield strength, controlled hardness and good impact toughness is essential. Yield strength reaches roughly 690 MPa (100 ksi) in the standard grades, which allows designers to reduce section thickness and structural weight substantially compared with ordinary carbon steel - typically by 25-30 % on heavily loaded members - while keeping enough ductility to deform before fracture.
Typical service includes crane booms and jibs, heavy construction and mining machinery frames, bridge components, pressure-bearing structural members and offshore platform hardware. Because the material is ordered against a wide family of lettered grades, the practical questions are always the same: which grade is available, what the equivalent designations are in other standards, and how the plate behaves during welding and machining.
What ASTM A514 Steel Plate Is
A514 is supplied in the quenched and tempered condition, a route that develops a fine, tempered martensitic or bainitic microstructure with a good balance of strength, hardness and toughness. In the base specification, the lettered grades - Grade B, E, F, H, Q, S and others - differ mainly in chemical balance, thickness capability and the minimum yield level that must be achieved, while all of them follow the same quenched and tempered process. The nearest international counterparts are the 690 MPa yield class grades described below.
A514 Steel Equivalent Grades in EN, DIN and GB Standards
| Standard | Equivalent grade | Description |
|---|---|---|
| EN 10025-6 | S690QL | Quenched and tempered high-strength structural plate, 690 MPa yield class with low-temperature impact testing |
| DIN 17102 | StE690V | Weldable fine-grain structural steel with high yield strength, normalised or thermo-mechanically treated family |
| GB/T 16270 | Q690C / Q690D / Q690E | Chinese high-strength low-alloy structural steel plate in the 690 MPa yield class |
| JIS | 690 MPa class quenched and tempered plate | Japanese quenched and tempered high-strength plate grades in the same strength band |
These matching grades give sourcing flexibility across regions, but they are equivalent in strength class rather than identical in chemistry: impact test temperature, carbon equivalent and thickness limits vary, so the specification on the enquiry should always name the standard and grade actually required.
Mechanical Properties of A514 Steel Plate
| Property | Typical range | Design significance |
|---|---|---|
| Yield strength | 620 - 690 MPa | Supports heavy loads with reduced plate thickness; tabulated values decrease slightly as thickness increases |
| Tensile strength | 690 - 890 MPa | Resists fracture under severe static and dynamic stress |
| Elongation | 18 - 20 % | Preserves a safety margin so members deform before catastrophic failure |
| Hardness | 235 - 293 HB (Brinell) | Balances wear resistance against machinability and weldability |
| Impact toughness | 20 ft-lbf minimum at -18 °C | Suitable for cold-climate, offshore and high-altitude service where brittle fracture is a risk |
A514 is also available with higher toughness requirements for low-temperature service, and the through-thickness behaviour of thick plate should be considered when welded connections transmit load perpendicular to the surface.
ASTM A514 Chemical Composition
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.12 - 0.21 |
| Manganese (Mn) | 0.70 - 1.00 |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.035 |
| Silicon (Si) | 0.15 - 0.35 |
| Chromium (Cr) | 0.40 - 0.65 |
| Nickel (Ni) | 0.40 - 0.65 |
| Molybdenum (Mo) | 0.15 - 0.25 |
| Vanadium (V) | ≤ 0.06 |
The alloying system - carbon and manganese for strength, chromium, nickel and molybdenum for hardenability and toughness - is the reason A514 can be quenched and tempered to a high strength level while still accepting welding when procedures are controlled. Ranges vary between lettered grades, and the exact limits applicable to a specific grade and thickness should be taken from the material specification on the order.
Welding, Machining and Fabrication Practice
Welding: A514 plate welds successfully with qualified procedures using low-hydrogen consumables matched to the base metal strength. Preheat, interpass temperature control and heat input limits reduce the risk of hydrogen cracking in the heat-affected zone.
Machinability: The steel is harder than mild steel but can be cut, drilled and machined with standard shop equipment after moderate adjustments to cutting speed, feed and tooling.
Thickness selection: Verify the yield and toughness values tabulated for the actual plate thickness, since properties fall slightly as sections become heavier.
Documentation: Plates are supplied with certificates that trace heat number, grade and mechanical test results, allowing the fabricator to demonstrate conformity with the specification.
Availability: Stock is concentrated in the 25-50 mm range, which supports faster delivery for crane and machinery work; other thicknesses are produced to order.
Frequently Asked Questions
Q: What is ASTM A514 steel equivalent to in European standards?
The closest equivalent is EN 10025-6 S690QL, a quenched and tempered plate in the 690 MPa yield class. DIN StE690V is a related German fine-grain designation, and GB/T 16270 Q690D or Q690E is the customary Chinese counterpart.
Q: How strong is A514 steel plate?
Yield strength is typically quoted in the 620-690 MPa range with tensile strength from 690 to 890 MPa, and elongation of 18-20 %. This strength level allows significantly thinner sections than ordinary structural steel.
Q: Can A514 steel be welded?
Yes. A514 is weldable when a qualified procedure is used: low-hydrogen consumables, controlled preheat for thicker sections and defined heat input limits keep the heat-affected zone sound and limit cracking risk.
Q: What is A514 plate used for?
Typical applications are crane booms and lifting equipment, heavy machinery and mining frames, bridge components and offshore structures - all cases where high strength reduces weight without sacrificing safety.
Q: What is the hardness of A514 steel?
Hardness normally falls between 235 and 293 HB, which gives useful wear resistance while still permitting cutting and machining with standard shop tooling and slightly reduced cutting speeds.
Q: Does A514 keep its strength in thick plate?
Strength is achieved through quenching and tempering across the section, but the specification's minimum values step down as thickness increases. Design should therefore use the value tabulated for the plate thickness actually purchased.
