Commercial Steel vs Forming Steel vs Drawing Steel: What They Really Mean

What “Commercial Steel / Forming Steel / Drawing Steel” Really Means

Understanding Ductility Grades in Coated Coil for Roll Forming

Terms like:

• Commercial Steel

• Forming Steel

• Drawing Steel

• Deep Drawing

• Extra Deep Drawing

Are commonly used in:

• ASTM specifications

• EN 10346

• JIS standards

• Global coated coil supply

Yet many buyers and even some manufacturers misunderstand what these classifications actually represent.

These are ductility classifications, not strength classifications.

They define:

• How much the steel can stretch

• How it behaves in bending and drawing

• How resistant it is to cracking

• Its suitability for complex shapes

They do NOT define:

• Structural load capacity

• Wind resistance

• Span performance

Understanding this distinction is critical in roll forming.

1️⃣ Commercial Steel (CS / SGCC / DX51D)

What It Means

Commercial steel is general-purpose cold-rolled steel designed for:

• Basic forming

• Light bending

• Simple profiles

• Non-load-bearing components

Examples:

• ASTM A653 CS Type B

• EN 10346 DX51D

• JIS SGCC

1.1 Mechanical Characteristics

Typical properties:

• Yield strength: ~200–280 MPa

• Moderate elongation

• Good basic bendability

• Not optimized for deep drawing

Commercial steel is the baseline grade.

1.2 Where It Is Used

• Roofing panels (light-duty)

• Wall cladding

• Light trim

• Appliance panels

• Basic sheet metal fabrication

2️⃣ Forming Steel (FS / DX52D / SGCD1)

What It Means

Forming steel is engineered for:

• Improved ductility

• Better bend performance

• Reduced cracking

• More complex forming

Compared to commercial steel, it allows greater plastic deformation.

2.1 Mechanical Characteristics

• Lower yield strength than structural grades

• Higher elongation

• Improved bend radius capability

• Reduced springback

It tolerates tighter bends than commercial grade.

2.2 Where It Is Used

• Complex roll formed shapes

• Deep flange sections

• Tight radii flashing

• Automotive parts

• Decorative cladding

3️⃣ Drawing Steel (DDS / DX53D / SGCD2)

What It Means

Drawing steel is optimized for:

• Deep drawing operations

• Severe deformation

• Multi-directional strain

This grade is used where material must stretch significantly without cracking.

3.1 Mechanical Characteristics

• Very high elongation

• Lower yield strength

• Excellent stretchability

• Minimal cracking in deep draw

This grade supports extreme forming operations.

3.2 Typical Applications

• Automotive body panels

• Pressed components

• Appliance housings

• Deep drawn industrial parts

Rarely used in structural roll forming.

4️⃣ Extra Deep Drawing (EDDS / DX54D / SGCD3)

Highest ductility classification.

Used for:

• Very severe forming

• Multi-stage deep draw

• Complex stamped geometries

Not typically required in standard roll forming profiles.

5️⃣ Key Engineering Differences

Grade Type	Yield Strength	Ductility	Bend Radius Capability	Structural Capacity
Commercial	Moderate	Moderate	Moderate	Low
Forming	Lower	Higher	Good	Low
Drawing	Lower	Very High	Excellent	Very Low
Structural (comparison)	High	Lower	Limited	High

Ductility increases as structural strength decreases.

6️⃣ Why This Matters in Roll Forming

Roll forming is primarily bending — not deep drawing.

However:

• Tight flange geometry

• Narrow hems

• Decorative shapes

• Small bend radii

May require forming or drawing grades.

Using structural high tensile material in these shapes increases:

• Edge cracking

• Surface tearing

• Springback

• Tool wear

7️⃣ Structural vs Ductility Trade-Off

If you choose:

Structural Grade (e.g., S350GD, G550):

• Higher load capacity

• Higher dent resistance

• Higher springback

• Higher crack risk at tight radii

If you choose:

Forming/Drawing Grade:

• Easier forming

• Reduced cracking

• Lower structural capacity

• Increased denting

The grade must match the application.

8️⃣ Coating Compatibility

Ductility grades exist under coated standards:

• ASTM A653

• EN 10346

• JIS G3302

Coating type (Z, AZ, etc.) is independent of ductility classification.

Example:

• DX51D + Z275
• CS Type B + G90
• SGCC + Z27

Strength and coating are separate decisions.

9️⃣ Common Misconceptions

Misconception 1

“Commercial steel is weak and useless.”

False. It is suitable for many non-structural applications.

Misconception 2

“Drawing steel is stronger.”

False. Drawing steel is more ductile, not stronger.

Misconception 3

“All galvanized roofing uses structural grade.”

Not always. Some markets use commercial or high tensile grades depending on design.

🔟 Roll Forming Machine Impact

Ductility grades affect:

• Forming force

• Pass design

• Springback compensation

• Roll wear

• Production speed

High ductility steel allows smoother forming and potentially higher speeds.

High tensile structural steel increases machine load.

1️⃣1️⃣ Buyer Strategy (30%)

Ask These Before Selecting Grade

1. Is the profile load-bearing?

2. What is minimum required yield strength?

3. What is the tightest bend radius?

4. Is cosmetic quality critical?

5. What is the environmental exposure?

6. What machine capability is available?

Use Commercial / Forming / Drawing When:

• Tight bends required

• Cosmetic finish critical

• Non-load-bearing profiles

• Deep drawn components

Use Structural Grade When:

• Wind load applies

• Structural certification required

• Span stiffness critical

• Framing systems involved

Common Buyer Mistakes

1. Using commercial grade for structural purlins

2. Using structural grade for tight flashing

3. Confusing ductility with strength

4. Ignoring bend radius limitations

5. Blaming machine for crack caused by wrong grade

6. Not requesting elongation data

6 Frequently Asked Questions

1. What is commercial steel?

A general-purpose steel suitable for basic forming but not structural load-bearing.

2. What is forming steel?

A more ductile steel designed for improved bend performance.

3. What is drawing steel?

Steel optimized for deep drawing and severe deformation.

4. Is drawing steel stronger?

No. It is more ductile, not stronger.

5. Can commercial steel be used for purlins?

Not recommended unless yield strength meets structural requirements.

6. Does coating affect whether steel is commercial or drawing?

No. Ductility classification is separate from coating type.

Final Engineering Summary

Commercial, forming, and drawing steels are ductility classifications, not structural classifications.

They define how much strain the steel can tolerate before cracking.

Structural grades define load capacity.

Choosing the correct category depends on:

• Profile geometry

• Structural requirement

• Bend radius

• Cosmetic expectation

• Machine capability

In roll forming, understanding this distinction prevents cracking, underperformance, and costly specification errors.