Structural Steel Properties — Yield Strength, Tensile Strength & Material Data
Complete reference for structural steel material properties. This page covers yield strength (Fy), tensile strength (Fu), elastic modulus (E), Poisson's ratio, density, thermal expansion, and elongation for every common structural steel grade used in building construction worldwide. All values are from ASTM, EN, and AS/NZS specifications.
Fundamental properties of structural steel
| Property | Symbol | Value (US) | Value (Metric) | Notes |
|---|---|---|---|---|
| Elastic modulus | E | 29,000 ksi | 200,000 MPa | Same for all carbon steel grades |
| Shear modulus | G | 11,200 ksi | 77,200 MPa | G = E / (2(1+v)) |
| Poisson's ratio | v | 0.30 | 0.30 | Same for all carbon steel grades |
| Density | rho | 490 lb/ft^3 | 7,850 kg/m^3 | Same for all carbon structural steel |
| Coefficient of thermal expansion | alpha | 6.5 x 10^-6 /F | 12 x 10^-6 /C | Linear, from 70F to 200F |
| Thermal conductivity | k | 27 Btu/(hr-ft-F) | 46 W/(m-C) | At room temperature |
These values are the same for ALL carbon structural steels (A36, A572, A992, A500, A588, S235, S355, etc.). The differences between grades are in Fy and Fu only.
Carbon steel properties by ASTM specification
ASTM A36 — Structural Steel (General Purpose)
| Property | Plates | Shapes (S, M, HP, L, C) | Bars |
|---|---|---|---|
| Fy (min) | 36 ksi | 36 ksi | 36 ksi |
| Fu (min) | 58-80 ksi | 58-80 ksi | 58-80 ksi |
| Elongation (min) | 20% in 8 in. | 20% in 8 in. | 20% in 8 in. |
Usage: Base plates, angles, channels, misc. framing. Being replaced by A572 Gr 50 and A992 for W-shapes.
ASTM A572 — High-Strength Low-Alloy Structural Steel
| Grade | Fy (ksi) | Fu (ksi) | Elongation (%) | Thickness Range |
|---|---|---|---|---|
| Gr 42 | 42 | 60 | 20 | Up to 6 in. |
| Gr 50 | 50 | 65 | 18 | Up to 4 in. |
| Gr 55 | 55 | 70 | 17 | Up to 2 in. |
| Gr 60 | 60 | 75 | 16 | Up to 1.25 in. |
| Gr 65 | 65 | 80 | 15 | Up to 1.25 in. |
Usage: W-shapes (Gr 50), plates for built-up members, bridge girders. Most common high-strength grade in US construction.
ASTM A992 — Structural Steel Shapes
| Property | Value | Notes |
|---|---|---|
| Fy (min) | 50 ksi | For shapes up to 2 in. flange thickness |
| Fy (max) | 65 ksi | Maximum specified yield |
| Fu (min) | 65 ksi | |
| Fy/Fu ratio | <= 0.85 | Ensures ductility |
| Elongation | 18% min in 8 in. |
A992 is the standard for all W-shapes in the US since 2000. It replaced A36 for wide-flange sections. The Fy/Fu ratio limit of 0.85 ensures the steel has adequate ductility for seismic applications. If you specify "A992" for a W-shape, you get Fy = 50 ksi, Fu = 65 ksi.
ASTM A500 — Cold-Formed Welded and Seamless Carbon Steel Structural Tubing (HSS)
| Grade | Fy (ksi) | Fu (ksi) | Shape |
|---|---|---|---|
| Gr B | 46 | 58 | Round HSS |
| Gr B | 46 | 58 | Square/Rectangular HSS |
| Gr C | 50 | 62 | Round HSS |
| Gr C | 50 | 62 | Square/Rectangular HSS |
Usage: HSS columns, braces, beams. Grade C (Fy = 50 ksi) is the most common specification.
ASTM A588 — High-Strength Low-Alloy Structural Steel (Weathering)
| Property | Value (plates) | Value (shapes) |
|---|---|---|
| Fy (min) | 50 ksi | 50 ksi |
| Fu (min) | 70 ksi | 70 ksi |
| Elongation | 18% in 8 in. | 18% in 8 in. |
Usage: Bridges, exposed structures where corrosion resistance eliminates painting. Forms a protective oxide layer (patina) when exposed to weather.
ASTM A514 — High-Yield-Strength Quenched and Tempered Alloy Steel Plate
| Grade | Fy (ksi) | Fu (ksi) | Thickness |
|---|---|---|---|
| Gr B | 100 | 110-130 | Up to 2.5 in. |
| Gr F | 100 | 110-130 | Up to 2.5 in. |
| Gr H | 100 | 110-130 | Up to 2 in. |
| Gr Q | 100 | 110-130 | Up to 6 in. |
Usage: Bridge girders, heavy truss chords, mining equipment. Cannot be welded without preheat and post-weld heat treatment.
ASTM A913 — High-Strength Low-Alloy Steel Shapes (Quenched and Self-Tempered)
| Grade | Fy (ksi) | Fu (ksi) | Application |
|---|---|---|---|
| Gr 50 | 50 | 65 | General construction |
| Gr 60 | 60 | 75 | Heavy columns |
| Gr 65 | 65 | 80 | Seismic moment frames |
| Gr 70 | 70 | 90 | Special seismic applications |
Usage: Heavy W-shapes (W14x700+). The quench-and-self-temper process gives higher strength with good weldability (no preheat required).
European steel grades (EN 10025)
EN 10025-2 — Non-alloy structural steels (S235, S275, S355)
| Grade | Fy (MPa) | Fu (MPa) | Elongation (%) | Thickness (mm) |
|---|---|---|---|---|
| S235JR | 235 | 360-510 | 26 | <= 16 |
| S235JR | 225 | 360-510 | 26 | 16-40 |
| S275JR | 275 | 410-560 | 23 | <= 16 |
| S275JR | 265 | 410-560 | 23 | 16-40 |
| S355JR | 355 | 470-630 | 22 | <= 16 |
| S355JR | 345 | 470-630 | 22 | 16-40 |
| S355J2 | 355 | 470-630 | 22 | <= 16 |
| S355J2 | 345 | 470-630 | 22 | 16-40 |
| S450J0 | 450 | 500-680 | 17 | <= 16 |
Note: Fy decreases with increasing thickness. The values above are for the thinnest category. S355JR at 40mm thickness has Fy = 345 MPa, not 355.
S355 is the European equivalent of ASTM A572 Gr 50 / A992. It is the standard grade for all European steel construction.
EN 10025-4 — Thermomechanically rolled fine-grain structural steels
| Grade | Fy (MPa) | Fu (MPa) | Charpy (J) | Thickness |
|---|---|---|---|---|
| S275M | 275 | 370-530 | 27 at -20C | <= 16 |
| S355M | 355 | 470-630 | 40 at -20C | <= 16 |
| S420M | 420 | 500-680 | 40 at -20C | <= 16 |
| S460M | 460 | 530-720 | 40 at -20C | <= 16 |
Usage: Heavy structures, bridges. Better toughness at low temperatures than S355JR.
Australian/New Zealand steel grades (AS/NZS 3679, AS/NZS 1163)
AS/NZS 3679.1 — Hot-rolled bars and sections
| Grade | Fy (MPa) | Fu (MPa) | Shape |
|---|---|---|---|
| 250 | 250 | 410 | UB, UC, WB, WC, PFC, angles |
| 300 | 300 | 440 | UB, UC, angles (standard grade) |
| 300Plus | 300 | 440 | Standard Australian structural grade |
| 350 | 350 | 480 | Heavy sections, plates |
| 400 | 400 | 500 | High-strength sections |
300Plus is the standard grade for Australian steel construction, equivalent to S355 (approximately) or A572 Gr 50.
AS/NZS 1163 — Cold-formed structural steel hollow sections
| Grade | Fy (MPa) | Fu (MPa) | Shape |
|---|---|---|---|
| C250 | 250 | 320 | CHS, RHS, SHS |
| C250L0 | 250 | 320 | CHS, RHS, SHS (impact tested) |
| C350 | 350 | 430 | CHS, RHS, SHS |
| C350L0 | 350 | 430 | CHS, RHS, SHS (impact tested) |
| C450 | 450 | 500 | CHS, RHS, SHS (high-strength) |
C350 is the standard grade for Australian HSS sections.
Canadian steel grades (CSA G40.21)
| Grade | Fy (MPa) | Fu (MPa) | Type |
|---|---|---|---|
| 260W | 260 | 410 | General purpose |
| 300W | 300 | 450 | Standard structural |
| 350W | 350 | 480 | W-shapes, HSS |
| 350AT | 350 | 480 | Seismic (toughness) |
| 380W | 380 | 490 | Heavy columns |
| 400W | 400 | 520 | High-strength |
| 700Q | 700 | 800-1000 | Quenched and tempered |
350W is the standard grade for Canadian steel construction. The "W" designation means weldable.
Steel properties at elevated temperatures
Steel loses strength and stiffness at high temperatures. This is critical for fire design.
| Temperature | Fy retained (%) | E retained (%) | Application |
|---|---|---|---|
| 20C (68F) | 100% | 100% | Room temperature |
| 200C (392F) | 100% | 90% | Near operating limit |
| 300C (572F) | 86% | 80% | |
| 400C (752F) | 70% | 70% | |
| 500C (932F) | 50% | 60% | Critical temperature |
| 600C (1112F) | 27% | 31% | Structural failure imminent |
| 700C (1292F) | 13% | 13% | Total loss of capacity |
| 800C (1472F) | 6% | 9% |
At 600C (1112F), steel retains only 27% of its yield strength. This is why fire protection (spray-applied fire-resistive material, intumescent coating, or concrete encasement) is required for structural steel in most buildings. AISC DG19 and EN 1993-1-2 provide detailed fire design methods.
Welding considerations by grade
| Grade | Preheat Required | Filler Metal | Special Requirements |
|---|---|---|---|
| A36 | None (<= 1.5 in.) | E70XX | None |
| A572 Gr 50 | None (<= 1.5 in.) | E70XX | None for Gr 42, 50 |
| A992 | None (<= 1.5 in.) | E70XX | Fy/Fu <= 0.85 (good for seismic) |
| A588 | 50-150F (thick) | E80XX (match weathering) | Use matching weathering electrode |
| A514 | 200-400F required | E110XX | Must preheat. Post-weld heat treatment may be required. |
| A913 Gr 65 | None | E70XX or E80XX | QST process gives good weldability |
| S355 | None (<= 30mm) | G46/G42 | CEV <= 0.45 for weldability |
| 300Plus | None (<= 25mm) | E49XX | Standard practice |
A514 requires the most caution. Preheat to 200-400F before welding, controlled interpass temperature, and post-weld heat treatment for thick sections. Failure to follow these requirements causes hydrogen-induced cracking.
Bolting considerations by grade
The steel grade of the connected member affects bearing and tear-out capacity:
| Steel Grade | Fu (ksi) | Bearing Capacity Factor | Notes |
|---|---|---|---|
| A36 | 58 | 1.0x (baseline) | Lower bearing capacity |
| A572 Gr 50 | 65 | 1.12x | 12% more bearing than A36 |
| A992 | 65 | 1.12x | Same as A572 Gr 50 |
| A588 | 70 | 1.21x | 21% more bearing than A36 |
| A514 | 110-130 | 1.90-2.24x | Massive bearing capacity |
For bearing calculations per AISC J3.10, the capacity is proportional to Fu. Going from A36 to A992 increases bearing capacity by 12%.
Comprehensive property comparison table
| Standard | Grade | Fy (ksi) | Fu (ksi) | E (ksi) | Density (lb/ft^3) | Primary Use |
|---|---|---|---|---|---|---|
| ASTM A36 | -- | 36 | 58 | 29,000 | 490 | Plates, angles, misc. |
| ASTM A572 | Gr 42 | 42 | 60 | 29,000 | 490 | Light W-shapes |
| ASTM A572 | Gr 50 | 50 | 65 | 29,000 | 490 | W-shapes, plates |
| ASTM A572 | Gr 65 | 65 | 80 | 29,000 | 490 | Bridge members |
| ASTM A992 | -- | 50 | 65 | 29,000 | 490 | W-shapes (standard) |
| ASTM A500 | Gr B | 46 | 58 | 29,000 | 490 | HSS (standard) |
| ASTM A500 | Gr C | 50 | 62 | 29,000 | 490 | HSS (high-strength) |
| ASTM A588 | -- | 50 | 70 | 29,000 | 490 | Weathering steel |
| ASTM A514 | Gr B | 100 | 110 | 29,000 | 490 | Bridge plates |
| ASTM A913 | Gr 65 | 65 | 80 | 29,000 | 490 | Heavy seismic columns |
| EN 10025 | S235 | 34 | 52 | 29,000 | 490 | Light European sections |
| EN 10025 | S275 | 40 | 59 | 29,000 | 490 | Medium European sections |
| EN 10025 | S355 | 51 | 68 | 29,000 | 490 | Standard European grade |
| EN 10025 | S450 | 65 | 73 | 29,000 | 490 | Heavy European sections |
| AS/NZS | 250 | 36 | 59 | 29,000 | 490 | Light Australian sections |
| AS/NZS | 300Plus | 44 | 64 | 29,000 | 490 | Standard Australian grade |
| AS/NZS | 350 | 51 | 70 | 29,000 | 490 | Heavy Australian sections |
| CSA | 350W | 51 | 70 | 29,000 | 490 | Standard Canadian grade |
Note: Metric Fy/Fu values converted to ksi for comparison (1 MPa = 0.145 ksi). E and density are identical across all grades.
Common mistakes
Assuming all steel is A36. A36 (Fy = 36 ksi) was the standard until 2000, but modern W-shapes are A992 (Fy = 50 ksi) — 39% stronger. Using A36 properties for A992 members over-designs by 39% in the wrong direction.
Ignoring thickness derating. For plates and shapes thicker than specified limits, Fy decreases. S355 at 40mm has Fy = 345 MPa, not 355 MPa. Always check the thickness range.
Confusing Fu with Fy. Fy (yield strength) is used for bending, compression, and shear yielding checks. Fu (tensile strength) is used for tension rupture, bearing, and block shear. They serve different purposes in AISC calculations.
Using the wrong grade for HSS. A500 Gr B has Fy = 46 ksi, not 50 ksi. If you need 50 ksi HSS, specify A500 Gr C. This is a 8% capacity difference.
Specifying A992 for non-W-shapes. A992 only applies to structural shapes (W, S, HP). Plates are A572 or A36. HSS is A500. Angles are A36 or A572. Specifying A992 for a plate will confuse the fabricator.
Not checking weldability for high-strength steels. A514 (Fy = 100 ksi) and A913 Gr 70 (Fy = 70 ksi) require special welding procedures, preheat, and filler metals. Standard E70XX electrodes are not adequate.
Frequently asked questions
What is the most common structural steel grade? In the US: A992 (Fy = 50 ksi) for W-shapes, A500 Gr C (Fy = 50 ksi) for HSS. In Europe: S355 (Fy = 355 MPa). In Australia: 300Plus (Fy = 300 MPa). In Canada: 350W (Fy = 350 MPa). All are approximately equivalent.
Is A992 the same as A572 Gr 50? Nearly. A992 has Fy = 50 ksi and Fu = 65 ksi, same as A572 Gr 50. The difference is that A992 has a maximum Fy of 65 ksi and a Fy/Fu ratio limit of 0.85, which A572 does not have. This makes A992 more predictable for seismic design. A992 is for shapes only; A572 Gr 50 is for both shapes and plates.
What is weathering steel (A588)? A588 forms a stable rust-like appearance (patina) that protects the underlying steel from further corrosion. It eliminates the need for painting in atmospheric exposure. It has Fy = 50 ksi and Fu = 70 ksi. Do not use in marine environments or where water accumulates. Requires special welding electrodes (E80XX-W series).
Why is the elastic modulus the same for all grades? E = 29,000 ksi (200,000 MPa) is a function of the iron crystal structure, not the chemical composition. Adding carbon, manganese, or micro-alloying elements changes Fy and Fu but has negligible effect on E. All carbon steels, regardless of grade, have the same E.
What steel grade should I specify? For W-shapes: ASTM A992 (automatic from any US mill). For HSS: ASTM A500 Gr C (50 ksi). For plates: ASTM A572 Gr 50. For angles/channels: ASTM A36. For exposed structures: ASTM A588 (weathering). For high-seismic columns: ASTM A913 Gr 65.
What is the difference between JR, J0, J2, and K2 in EN 10025? These designate the Charpy V-notch impact test temperature. JR = 27J at 20C. J0 = 27J at 0C. J2 = 27J at -20C. K2 = 40J at -20C. For structural design in cold climates, specify J2 or K2 for adequate toughness.
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Related references
- Steel Grades Chart
- Steel Density Table
- Steel Material Properties
- High-Strength Steel Grades
- Steel Grades Fy & Fu
- ASTM A36 Steel
- Stress-Strain Curve
- Weld Electrodes
- Fire Resistance
- How to Verify Calculations
Disclaimer
This page is for educational and reference use only. It does not constitute professional engineering advice. All design values must be verified against the applicable standard and project specification before use. The site operator disclaims liability for any loss arising from this information.