A572 vs A36 Steel – What’s the Difference? Complete Guide

ASTM A36 and ASTM A572 are two widely used structural steels, found in applications ranging from bridges and construction to energy facilities, industrial manufacturing, and road plates. When selecting the right material for a project, understanding the critical differences between these two steels is essential, as it significantly impacts performance, cost, and durability.

1.0 A36 vs A572: A Quick Overview

1.1 Introduction to ASTM A36

ASTM A36 is a low-carbon steel, known for its excellent weldability and ease of fabrication, making it ideal for general structural and manufacturing applications. With a low carbon content (typically no more than 0.26%), it is highly suitable for cutting, welding, and forming operations.

Advantages	Common Applications
Low cost	General structural applications
Easy to weld and machine	Light to medium-load framing
Widely available	Road plates, equipment bases, and more

1.2 Introduction to ASTM A572 (Focus on Grade 50)

ASTM A572 is a high-strength, low-alloy steel (HSLA) that contains elements like manganese and phosphorus to enhance its strength and durability. Grade 50, one of the most common grades, is widely used in heavy-load structures due to its superior yield strength and excellent weldability.

2.0 How to Choose Between A36 and A572

When selecting between A36 and A572, the following factors should be considered:

Advantages	Common Applications
High strength (approximately 1.4 times the yield strength of A36)	High-strength bridge structures
Better corrosion resistance	Steel frameworks for high-rise buildings
Reduces the amount of steel required, leading to lighter structures	Industrial buildings and heavy equipment support

2.1 Chemical Composition of ASTM A36 Steel

Alloying Element	Thickness ≤ ¾”	>¾” to 1½”	>1½” to 2½”	>2½” to 4”	>4”
Max Carbon	0.25%	0.25%	0.26%	0.27%	0.29%
Manganese	Not specified	0.80–1.20%	0.80–1.20%	0.85–1.20%	0.85–1.20%
Max Phosphorus	0.030%	0.030%	0.030%	0.030%	0.030%
Max Sulfur	0.030%	0.030%	0.030%	0.030%	0.030%
Silicon	≤ 0.40%	≤ 0.40%	0.15–0.40%	0.15–0.40%	0.15–0.40%
Copper (min)	0.20%	0.20%	0.20%	0.20%	0.20%

2.2 Chemical Composition of ASTM A572 Steel

Grade	42	50	55	60	65	65 (Thickness >½” to 1¼”)
Max Carbon	0.21%	0.23%	0.25%	0.26%	0.26%	0.23%
Max Manganese	1.35%	1.35%	1.35%	1.35%	1.35%	1.65%
Max Phosphorus	0.030%	0.030%	0.030%	0.030%	0.030%	0.030%
Max Sulfur	0.030%	0.030%	0.030%	0.030%	0.030%	0.030%
Silicon	0.15–0.40%	0.15–0.40%	0.15–0.40%	0.40%	0.40%	0.40%

2.3 Mechanical Properties of ASTM A36 and ASTM A572 Steel Plates

Grade	Yield Point (min)	Tensile Strength
A36	36,000 psi (250 MPa)	[Data not provided in source]
A572-50	50,000 psi (345 MPa)	[Typically ~65,000 psi / 450 MPa]

Note: The tensile strength data for A36 and A572-50 were incomplete in your source. Please let me know if you’d like complete values inserted from standard references (e.g., ASTM or SAE tables).

3.0 Which Steel is More Suitable for Welding Workbenches? ASTM A36 vs ASTM A572 Grade 50

Selecting the right steel for manufacturing welding workbenches is crucial. Two common options are ASTM A36 and ASTM A572 Grade 50. To help you make a more informed decision, we will systematically compare these two steels in terms of chemical composition and mechanical properties.

3.1 Chemical Composition Comparison

Let’s begin by looking at the chemical compositions of these two materials:

Element	A572 Gr 50	A36
Carbon (C)	≤ 0.26%	≤ 0.26%
Manganese (Mn)	≤ 1.65%	Not specified
Phosphorus (P)	≤ 0.040%	≤ 0.040%
Sulfur (S)	≤ 0.050%	≤ 0.050%
Silicon (Si)	≤ 0.40%	≤ 0.40%
Copper (Cu)	–	≥ 0.20%

Analysis:

• Carbon content:Both are low-carbon steels (carbon content less than 0.30%), which provide good weldability and formability.
• Manganese addition:A572-50 contains a higher amount of manganese, which improves strength and toughness while offering some corrosion resistance.
• Copper content:A36 contains at least 0.20% copper, which slightly enhances corrosion resistance.

Conclusion: A572-50’s alloy composition is more favorable for enhancing strength and fatigue performance, making it more suitable for heavy-duty and durability-critical structures.

3.2 Mechanical Properties Comparison

In workbench applications, the steel needs to have good load-bearing capacity and fatigue resistance. Below are key performance parameters compared:

Performance Metric	A572 Gr 50	A36	Improvement (%)
Yield Strength	≈ 390 MPa	≈ 290 MPa	+34.5%
Tensile Strength	≈ 500 MPa	≈ 400–550 MPa	Slightly higher, depending on specification
Fatigue Strength	≈ 280 MPa	≈ 200 MPa	+40%

1. 56Yield Strength:A572 Gr 50 significantly outperforms A36, making it better suited for high-load workbench structures.
2. Fatigue Strength:A572-50 performs better under repetitive loads, making it ideal for long-term use.
3. Weldability:Both steels are low-carbon, offering good weldability. However, A36 is easier to weld and machine, especially for complex operations.

3.3 Recommended Materials for Welding Workbenches

A36 vs A572: Choosing Steel for Welding Workbenches
When selecting steel for manufacturing welding workbenches, both A36 and A572 Grade 50 are common choices. We will compare their chemical composition and mechanical properties to help you make a more informed decision.

Chemical Composition Comparison:

Element	A572 Gr 50	A36
Carbon (C)	≤ 0.26%	≤ 0.26%
Manganese (Mn)	≤ 1.65%	Not specified
Phosphorus (P)	≤ 0.040%	≤ 0.040%
Sulfur (S)	≤ 0.050%	≤ 0.050%
Silicon (Si)	≤ 0.40%	≤ 0.40%
Copper (Cu)	–	≥ 0.20%

Mechanical Properties Comparison:

Performance Indicator	A572 Gr 50	A36	Improvement
Yield Strength	≈ 390 MPa	≈ 290 MPa	+34.5%
Tensile Strength	≈ 500 MPa	≈ 400–550 MPa	Slightly higher
Fatigue Strength	≈ 280 MPa	≈ 200 MPa	+40%

Yield Strength: A572 Gr 50 has a significantly higher yield strength than A36, making it more suitable for high-load workbench structures.

Fatigue Strength: A572-50 performs better under repeated loading, making it ideal for long-term use.

Weldability: Both are low-carbon steels with good weldability. However, A36, with its lower alloy content, is relatively easier to weld and process.

Recommended Materials:

Application Scenario	Recommended Steel	Reason
General use, budget-conscious	ASTM A36	Lower cost, suitable for medium-load applications.
Heavy load, frequent impact	ASTM A572 Gr 50	Higher strength and fatigue resistance, ideal for high-strength and durability requirements.

3.4 Comparison of ASTM A36 (SS400/S275 Structural Carbon Steel) and ASTM A572 HSLA Steel (Including Grade 50)

Property Type	Specific Property	ASTM A36	ASTM A572 HSLA
Mechanical Properties	Brinell Hardness (HB)	140	140–190
	Elastic Modulus (GPa)	190	190
	Elongation at Break (%)	22	18–25
	Fatigue Strength (MPa)	200	240–340
	Poisson’s Ratio	0.29	0.29
	Shear Modulus (GPa)	73	73
	Shear Strength (MPa)	300	300–380
	Ultimate Tensile Strength, UTS (MPa)	480	470–620
	Yield Strength (MPa)	290	330–510
Thermal Properties	Latent Heat of Fusion (J/g)	250	250
	Max Service Temperature (°C)	400	400
	Liquidus Temperature (°C)	1460	1460
	Solidus Temperature (°C)	1420	1420
	Specific Heat Capacity (J/kg·K)	470	470
	Thermal Conductivity (W/m·K)	50	51
	Thermal Expansion Coefficient (µm/m·K)	11	13
Electrical Properties	Electrical Conductivity (Volumetric % IACS)	12	7.2
	Electrical Conductivity (Mass % IACS)	14	8.2–8.3
Other Properties	Relative Cost (%)	1.8	2.0
	Density (g/cm³)	7.9	7.8

4.0 A36 vs A572: Can They Be Interchanged? Cost Differences and Typical Uses

During the engineering design and material selection phase, a common question is: Can ASTM A36 and A572 be interchanged? Although both are low-carbon structural steels, they are not completely interchangeable in terms of performance, alloy composition, application scenarios, and cost.

4.1 Can A36 and A572 Be Interchanged?

No, they cannot be simply interchanged.
While both A36 and A572 (especially Grade 50) are commonly used for structural applications (such as bridges and building support members), A572 offers higher strength and wear resistance, making it better suited for high-load structural scenarios, such as transmission towers, large trusses, or heavy-duty industrial frames.

If your application requires high strength and fatigue life, A36 cannot replace A572. On the other hand, if your project demands ease of fabrication and cost control, A36 is a better choice.

4.2 Cost Comparison

Item	A36	A572-50
Yield Strength	36,000 PSI (≈ 250 MPa)	50,000 PSI (≈ 345 MPa)
Strength Source	Carbon + Manganese	Carbon + Manganese + Nb/V and other strengthening alloys
Unit Price Difference	–	2.5%–5% higher

Conclusion: A572-50 costs slightly more due to alloying elements and strength improvements. However, in high-strength applications, it can reduce the amount of steel used, offering material savings and performance advantages in the overall structure.

4.3 Common Uses Comparison

✅ Common Uses for A36 (easy to process, cost-sensitive scenarios):

• Welding workbenches, fixture bases
• General manufacturing structural components (cutting, bending, etc.)
• Light-load frames, fences, brackets, etc.
• Products requiring longer processing times

✅ Common Uses for A572 Gr 50 (high-strength load-bearing scenarios):

• Transmission towers, bridge components
• High-stress building frameworks
• Designs that optimize component sections and reduce weight
• Heavy machinery frames

4.4 Material Usage Recommendations

Comparison Dimension	A36 Advantages	A572 Advantages
Weldability	Better, suitable for precise welding and high-weld standard projects	Slightly lower, due to alloying elements slightly complicating welding
Workability	Excellent, suitable for milling, drilling, forming, etc.	Good, but harder, slightly increases machining difficulty
Cost Control	Lower cost, ideal for low-strength batch products	Initial cost slightly higher, but reduces material usage
Strength & Durability	Suitable for general structural needs	Ideal for heavy-duty and fatigue-life critical projects

4.5 Conclusion: How to Choose?

If your project focuses on weldability, formability, processing efficiency, and budget control, ASTM A36 is the better choice.

If your project requires high structural strength, durability, and optimized component weight, especially in high-load environments, ASTM A572 Grade 50 is the more suitable option.

	Carbon Footprint (kg CO₂/kg)	1.4	1.6
	Embodied Energy (MJ/kg)	18	22
	Water Usage (L/kg)	44	47
Performance Metrics	Specific Fracture Energy (MJ/m³)	92	100–110
	Toughness Modulus (kJ/m³)	220	290–690
	Axial Strength Score (points)	13	13
	Flexural Strength Score (points)	24	24
	Strength Index: Axial/Flexural	17 / 17	17–22 / 17–21
	Thermal Diffusivity (mm²/s)	14	14
	Thermal Shock Resistance Rating (points)	16	14–18

5.0 A36 vs A572: Choosing the Right Steel for Metalworking Equipment

A36 Steel: Ideal for light-duty equipment like Plate Rolling Machines, Press Brake Machines, offering excellent weldability, ease of machining, and cost-efficiency for moderate loads.

A572 Grade 50 Steel: Best for heavy-duty equipment like Tube Laser Cutting Machines and Decoiler Machines. Provides higher strength, superior fatigue resistance, and durability for demanding applications.

Key Considerations:

• Load Requirements: A36 is suitable for light-duty equipment, while A572 is better for heavy-duty equipment with high load and durability needs.
• Workability: A36 is easier to machine, making it perfect for base plates and frames of Plate Rolling Machines and Press Brake Machines, while A572 requires more precision for heavy-duty equipment.
• Cost Consideration: A36 is more cost-effective for light-duty machines, while A572, though more expensive, offers long-term savings due to its superior strength and reduced material usage.

 

Reference:
https://en.wikipedia.org/wiki/Carbon_steel

www.bushwickmetals.com/a572-vs-a36-grade-comparison-and-uses/