The backbone of construction. We supply certified A36 plates and bars featuring the standard 29,000 ksi (200 GPa) elastic modulus for predictable structural performance.
Understanding "Stiffness" vs. "Strength" in Structural Engineering.
1. What is Elastic Modulus?
Also known as Young's Modulus (E), it measures the "stiffness" of the steel. It defines how much the material will stretch or bend under a given load before it permanently deforms.
Think of A36 steel as a very stiff spring. The Modulus (29,000 ksi) tells you how hard you have to pull that spring to stretch it.
2. Global Unit Conversions
Unit System
Value
Common Usage
Imperial (US)
29,000 ksi
Structural Design
Imperial (Alt)
29 x 10⁶ psi
Lab Testing
Metric (SI)
200 GPa
International
Metric (Alt)
200,000 MPa
Mechanical Eng.
// ENGINEER'S NOTE: STIFFNESS IS CONSTANT
Myth: High-strength steel (like A572-50) is stiffer than A36. Fact: They have the same Elastic Modulus (29,000 ksi). Using expensive high-strength steel won't reduce deflection (bending). For stiffness-driven designs, A36 is the most cost-effective choice.
Stress-Strain Curve: Mild Steel (A36)
Beyond Stiffness: Strength Data
Elastic Modulus (29,000 ksi) is constant, but Yield Strength defines the grade.
ASTM A36 SPECIFICATION [TAB-03]
Yield StrengthDeformation Point
IMPERIAL
36,000 psi
METRIC
250 MPa
Tensile StrengthUltimate Break
IMPERIAL
58 - 80 ksi
METRIC
400 - 550 MPa
ElongationDuctility (in 8")
MINIMUM
20% Min
MINIMUM
20% Min
Brinell HardnessTypical Value
RANGE
119 - 159
UNIT
HB
PERFORMANCE COMPARISON
Yield Strength Analysis
(Higher Bar = Stronger Material)
36 ksi
A36 Standard
~40 ksi
1018 Cold Roll
50 ksi
A572-50 HSLA
Engineering Insight: A36 is the "baseline". Upgrade to A572-50 only if load calcs exceed 36 ksi.
Primary Applications for A36
Utilizing the 29,000 ksi Elastic Modulus for structural stability and deflection control.
REQ: HIGH STIFFNESS (E)
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Structural Framework
The standard choice for I-beams, H-beams, and channels in warehouse and high-rise construction where loads are static.
Why A36?
High Modulus (29,000 ksi) resists beam sagging (deflection) under gravity loads better than aluminum or timber.
REQ: DUCTILITY
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Bridge Components
Used for short-span bridge girders, pedestrian walkways, and guardrails where weldability and safety are paramount.
Why A36?
20% minimum elongation ensures a safe failure mode (the steel stretches visibly before breaking), critical for public safety.
REQ: VIBRATION DAMPING
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Machine Base Plates
Heavy A36 plates (up to 12" thick) provide a rigid, flat foundation for mounting motors, pumps, and generators.
Why A36?
Mass + Stiffness (E) minimizes vibration transmission and maintains precise equipment alignment.
REQ: WELDABILITY
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General Fabrication
The "go-to" steel for storage tanks, agricultural equipment, and truck frames due to its low cost and ease of modification.
Why A36?
Low carbon (<0.26%) means it can be welded without pre-heating, reducing fabrication time and cost.
Available Forms & Sizes
Standard stock items ready for immediate shipment. All materials include Mill Test Reports (MTRs).
A36 Plate
⬜
Thickness3/16" - 12.00"
Widths48", 60", 96", 120"
Lengths96", 120", 240", 480"
AvailabilityIn Stock
Structural Shapes
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Angles (L)1/2" to 8" leg
Channels (C)3" to 15" depth
Beams (W/S)4" to 24" depth
AvailabilityHigh Vol.
Bar Stock
📏
Round Bar1/4" to 12" dia
Flat Bar1/8" to 3" thick
Square Bar3/8" to 4" side
AvailabilityIn Stock
Need Custom Sizes?
Don't buy full plates if you don't need to. We offer value-added processing to deliver "project-ready" materials.
🔥Flame Cutting
🌊Waterjet
⚙️Drilling
📐Grinding
Technical FAQ
Common engineering queries regarding thermal and physical properties.
Does Elastic Modulus change with temperature?
Yes. The modulus of elasticity is inversely proportional to temperature. While A36 retains its stiffness (29,000 ksi) at room temperature, it begins to drop significantly above 200°C (400°F).
For example:
At 20°C (68°F): E = 29,000 ksi
At 500°C (932°F): E ≈ 20,000 ksi (Approx 30% reduction)
For high-temperature structural applications, fire-proofing or specialized alloy steels should be considered.
Is ASTM A36 steel magnetic?
Yes, strongly ferromagnetic. A36 is a low-carbon steel composed primarily of Iron (Fe) (>98%). It can be easily lifted using magnetic cranes and is suitable for magnetic shielding applications or electromagnetic devices.
Is A36 steel difficult to weld?
No. A36 is considered the easiest structural steel to weld. Its low carbon content (< 0.26%) prevents the formation of brittle martensite in the Heat Affected Zone (HAZ).
It can be welded using all standard methods (Stick, MIG, TIG) following AWS D1.1 standards. Pre-heating is generally not required for sections thinner than 3/4".
What is the difference between A36 and 1018?
While chemically similar, they differ in specification and finish:
ASTM A36 is a "Structural Grade" focusing on mechanical properties (Min Yield 36 ksi). It is typically Hot Rolled with a rougher mill scale finish.
AISI 1018 is a "Chemical Grade" focusing on precise composition. It is typically Cold Rolled (Cold Finished), offering tighter dimensional tolerances, a smoother surface, and slightly higher yield strength (~54 ksi) due to work hardening.
Use A36 for beams/plates; use 1018 for machined shafts/pins.
