What is A36 Steel Properties used for in structural engineering?

A36 Steel Properties provides values required for steel design calculations including capacity checks, connection design, and detailing. It is referenced in structural design codes and used by practicing engineers during the design of buildings, bridges, and industrial structures.

Can I use these reference values directly in my design?

Yes, provided the values match your governing code edition and project specifications. Always cross-reference against the primary source (code document, manufacturer data, or published standard). The information on this page is for educational use — final verification by a licensed engineer is required.

How often are these reference values updated?

Reference content is maintained to align with current code editions. When a new edition of AISC 360, AS 4100, EN 1993, or CSA S16 is published, values are reviewed and updated. Check the last-modified date at the bottom of the page and verify against the current edition for your jurisdiction.

A36 Steel Properties — Yield Strength, Tensile Strength & Applications

ASTM A36 steel is the most widely used carbon structural steel in the United States. With a yield strength of 36 ksi (248 MPa) and tensile strength of 58 ksi (400 MPa), A36 provides excellent weldability, ductility, and economy for general structural applications. This page covers complete A36 mechanical properties, chemical composition, weldability, and AISC 360 design guidance.

Quick access: US Steel Grades → | A992 Steel → | Beam Calculator → | Section Properties →

A36 Steel Mechanical Properties

Yield and Tensile Strength

Property	Imperial	Metric	AISC 360 Symbol
Yield strength (Fy)	36 ksi	248 MPa	Fy
Tensile strength (Fu)	58 ksi	400 MPa	Fu
Modulus of elasticity (E)	29,000 ksi	200,000 MPa	E
Shear modulus (G)	11,200 ksi	77,200 MPa	G
Poisson's ratio	0.30	0.30	—
Density	490 lb/ft³	7,850 kg/m³	—

Elongation Requirements

Specimen	Minimum Elongation
8-inch gauge length	20%
2-inch gauge length	23%

Charpy V-Notch Impact Properties

A36 does not have mandatory CVN requirements in the base specification. For fracture-critical applications, specify supplementary requirement S5 (CVN testing at specified temperature) per ASTM A6.

A36 Chemical Composition

Element	Maximum (%)	Typical (%)
Carbon (C)	0.26	0.20
Manganese (Mn)	—	0.80
Phosphorus (P)	0.04	0.02
Sulfur (S)	0.05	0.03
Silicon (Si)	0.40	0.25
Copper (Cu)	0.20 min	0.30

The relatively low carbon content (max 0.26%) makes A36 highly weldable without preheat for most thicknesses.

Carbon Equivalent (CE)

A36 does not have a specified CE limit. Typical CE values range from 0.35 to 0.45. Per AWS D1.1, preheat is generally not required for A36 when:

Thickness ≤ 3/4 inch (19 mm) with low-hydrogen electrodes
Thickness ≤ 1.5 inch (38 mm) with E70XX electrodes and base metal above 32°F (0°C)

Weldability

A36 is one of the most weldable structural steels. Key welding considerations:

Electrode Selection

Process	Recommended Electrode	Notes
SMAW (stick)	E7018, E7016	Low-hydrogen for all structural work
FCAW	E71T-1, E70T-1	All-position, good for field welding
GMAW (MIG)	ER70S-6	Solid wire, CO2 or 75/25 Ar/CO2
SAW	F7A2-EM12K	Submerged arc for shop fabrication

Preheat Requirements

Thickness	Preheat (AWS D1.1)
Up to 3/4 in. (19 mm)	Not required (above 32°F)
3/4 to 1-1/2 in. (19-38 mm)	50°F (10°C) minimum
1-1/2 to 2-1/2 in. (38-64 mm)	150°F (65°C) minimum
Over 2-1/2 in. (64 mm)	200°F (93°C) minimum

Hydrogen Concerns

Use low-hydrogen electrodes (H4 or H8 designation) for all structural welding. A36's low carbon content minimizes hydrogen-induced cracking risk, but proper electrode handling (baking, storage) is still required per AWS D1.1.

A36 vs Other US Steel Grades

Property	A36	A992	A572 Gr 50	A588	A500 Gr C
Fy (ksi)	36	50	50	50	50
Fu (ksi)	58	65	65	70	62
Fy/Fu ratio	0.62	0.77	0.77	0.71	0.81
Weldability	Excellent	Good	Good	Good	Good
Cost	Baseline	Same as A572	+5-10%	+15-25%	+5-10%
Product forms	Plates, bars, shapes	W-shapes only	Plates, bars, shapes	Plates, shapes	HSS

When A36 is Preferred

Base plates (economy, availability)
Connection plates (standard practice)
Angles and channels (standard production)
Renovation work matching existing A36 steel
Non-critical secondary framing

When to Upgrade from A36

W-shape beams and columns: Use A992 (standard, stronger)
Heavy plates in welded girders: Use A572 Grade 50 (higher strength, better weldability)
Exposed outdoor structures: Use A588 (weathering)
Seismic moment frames: Use A992 or A1085 (guaranteed Fy/Fu ratio)

AISC 360 Design with A36

Available Strength in Tension

For a plate with gross area Ag and net area An:

Limit State	LRFD (phi)	ASD (Omega)	Formula
Yielding	0.90	1.67	Pn = Fy × Ag = 36Ag
Fracture	0.75	2.00	Pn = Fu × An = 58An

Available Strength in Compression

For a compact section (no local buckling):

Pn = Fy × Ag = 36Ag (for short columns where Fcr = Fy)

For slender columns, Euler buckling governs: Pe = π²EI/(KL)²

Available Strength in Flexure

For compact sections with full lateral support:

Mn = Mp = Fy × Zx = 36Zx (where Zx is the plastic section modulus)

Worked Example — A36 Plate in Tension

Problem: A 3/4" x 10" A36 plate with two lines of 7/8" diameter bolts. Find the available tensile strength.

Given:

Plate: 3/4" x 10" (Ag = 7.50 in²)
Bolts: 2 lines of 7/8" dia, 3 bolts per line
Hole diameter: 7/8" + 1/16" = 15/16" per AISC

Solution:

Net area: An = 7.50 - 2(15/16)(3/4) = 7.50 - 1.406 = 6.094 in²
Yielding: phiPn = 0.90 × 36 × 7.50 = 243 kips
Fracture: phiPn = 0.75 × 58 × 6.094 = 265 kips
Governs: 243 kips (yielding)

Worked Example — A36 Angle in Compression

Problem: Check an L4x4x3/8 A36 angle, KL=8 ft.

Given:

L4x4x3/8: Ag = 2.86 in², rx = ry = 1.23 in, rz = 0.776 in
KL = 8 ft = 96 in

Solution:

KL/r = 96/1.23 = 78.0 (using governing radius of gyration)
Fe = π²E/(KL/r)² = π²(29,000)/78.0² = 47.0 ksi
Fy/Fe = 36/47.0 = 0.766 < 2.25
Fcr = 0.658^0.766 × 36 = 0.734 × 36 = 26.4 ksi
Pn = Fcr × Ag = 26.4 × 2.86 = 75.5 kips
LRFD: phiPn = 0.90 × 75.5 = 68.0 kips
ASD: Pn/Omega = 75.5/1.67 = 45.2 kips

A36 for Base Plates

A36 is the standard grade for column base plates in the US. Key design considerations:

Why A36 for Base Plates

Economy — A36 plate is the lowest-cost structural plate available
Availability — Stocked in all thicknesses from 3/8" to 4" at most service centers
Adequate strength — Base plate thickness is usually governed by bearing and bending, not yield strength
Weldability — Easy to weld column stubs and anchor rods

Base Plate Thickness Calculation

For a W12x53 column (d=12.1", bf=10.0") on a 16"x16" A36 base plate with factored load Pu=400 kips:

Bearing area required: Ab = Pu/(0.85f'c) = 400/(0.85×4) = 117.6 in²
Base plate area: 16×16 = 256 in² (OK, exceeds required)
Cantilever distance: m = (16-0.95×12.1)/2 = 2.25 in, n = (16-0.8×10.0)/2 = 4.0 in
Critical distance: l = max(m,n) = 4.0 in
Required thickness: tp = l × sqrt(2Pu/(0.9Fy × B × N)) = 4.0 × sqrt(2×400/(0.9×36×16×16))
tp = 4.0 × sqrt(800/82944) = 4.0 × 0.0984 = 0.39 in
Use 1/2" plate (tp = 0.50" > 0.39") — A36 1/2" plate is economical

Calculator

Design steel members with A36 steel using our free calculators:

Beam Capacity Calculator → — Check flexural strength for A36 beams
Column Buckling Calculator → — AISC compression capacity
Bolted Connection Calculator → — Shear tab and splice design
Section Properties → — Full AISC section database

FAQ

Q: What is the yield strength of A36 steel? A: ASTM A36 steel has a minimum yield strength of 36 ksi (248 MPa) and a minimum tensile strength of 58 ksi (400 MPa). These values apply to all thicknesses up to 8 inches (200 mm).

Q: Is A36 steel weldable? A: Yes, A36 is one of the most weldable structural steels. Its low carbon content (max 0.26%) means preheat is generally not required for thicknesses up to 3/4 inch (19 mm). Use E7018 low-hydrogen electrodes for all structural welding.

Q: What is the difference between A36 and A572 Grade 50? A: A36 has Fy=36 ksi and Fu=58 ksi. A572 Grade 50 has Fy=50 ksi and Fu=65 ksi. A572-50 is 39% stronger in yield. Use A36 for base plates, connection plates, and secondary framing. Use A572-50 for plates in welded girders and heavy construction.

Q: Can I use A36 for W-shape beams? A: While A36 W-shapes were historically available, modern W-shape production uses A992 (Fy=50 ksi) exclusively. A992 is stronger, has better ductility controls (Fy/Fu ratio), and costs the same. Use A992 for all new W-shape designs.

Q: What electrodes should I use to weld A36 steel? A: Use E7018 (SMAW/stick), E71T-1 (FCAW/flux-cored), or ER70S-6 (GMAW/MIG). All are low-hydrorogen electrodes suitable for structural steel. For submerged arc welding, use F7A2-EM12K.

Q: Is A36 steel magnetic? A: Yes, A36 is a carbon steel and is ferromagnetic. It is attracted to magnets, unlike austenitic stainless steels (300 series) which are non-magnetic.