SMP Coated Steel Roll Forming Material Guide: Silicone Modified Polyester, Coil Sizes & Uses

SMP Coated Steel Roll Forming Material (Silicone Modified Polyester)

1. Overview of SMP Coated Steel in Roll Forming

SMP (Silicone Modified Polyester) coated steel is a pre-painted steel product that uses a silicone-enhanced polyester coating system. It offers improved durability, weather resistance, and color retention compared to standard polyester (PE) coatings.

In roll forming, SMP coated steel is widely used for roofing and cladding applications where longer lifespan and better UV resistance are required without the higher cost of premium coatings like PVDF.

SMP is commonly applied to both galvanized steel (PPGI) and Aluzinc steel (PPGL), making it a versatile mid-range coating solution.

2. Material Composition & Structure

SMP coated steel consists of:

• Steel base (cold rolled steel)
• Zinc or Aluzinc coating
• Chemical pre-treatment
• Primer layer
• SMP topcoat
• Backing coat

Layer Structure:

1. Steel core
2. Zinc or Aluzinc coating
3. Chemical pre-treatment
4. Primer coating
5. SMP topcoat
6. Back coat

3. Available Coil Specifications

Thickness Range

• 0.25mm – 1.2mm

Coil Width

• 600mm – 1250mm

Coil Weight

• 3 tons – 10 tons

Coil ID / OD

• ID: 508mm / 610mm
• OD: up to 1400mm

Tolerance

• Tight thickness tolerance
• High surface quality

4. Mechanical Properties

Typical values:

• Yield Strength: 180 – 350 MPa
• Tensile Strength: 300 – 550 MPa
• Elongation: 10% – 25%
• Hardness: 100 – 180 HB

Grades:

• DX51D
• S320GD / S350GD

5. Coating Types (SMP SYSTEM)

SMP Coating

• Thickness: 20–30 microns (top coat)
• Back coat: 5–10 microns

Lifespan

• 15–20 years

Performance

• Better UV resistance than PE
• Improved chalk resistance
• Enhanced durability

Cost Level

• Medium

6. Surface Finishes

• Gloss
• Matte
• Textured
• Smooth finish
• Wide color options

7. Common Roll Forming Applications

SMP coated steel is used in:

• Roofing panels (PBR, trapezoidal, standing seam)
• Wall cladding systems
• Industrial buildings
• Agricultural structures
• Commercial buildings
• Prefabricated buildings

8. Advantages of SMP Coated Steel

• Better durability than PE
• Improved color retention
• Good corrosion resistance
• Cost-effective vs PVDF
• Suitable for outdoor use

9. Disadvantages / Limitations

• More expensive than PE
• Lower performance than PVDF
• Can still fade over time
• Paint cracking possible in tight bends

10. Roll Forming Machine Considerations

Roll Tooling

• Chrome plated rollers essential
• Smooth finish required

Speed

• 10–40 m/min

Lubrication

• Often recommended

Cutting

• Flying shear preferred
• Clean cuts critical

Common Issues

• Paint cracking
• Surface scratching
• Roller marks
• Oil canning

11. Common Problems in Production

• Surface scratches
• Paint cracking during forming
• Color variation between batches
• Oil canning in roofing panels
• Handling damage

12. Pricing Guide

Typical global pricing:

• Low: $950–$1150 per ton
• Medium: $1150–$1450 per ton
• High: $1450–$1800+ per ton

Factors affecting price:

• Base material (GI or Aluzinc)
• Paint thickness
• Color and finish
• Supplier

13. Comparison with Other Materials

SMP vs PE

• SMP = better durability and UV resistance
• PE = cheaper

SMP vs PVDF

• SMP = lower cost
• PVDF = superior lifespan

SMP vs Plastisol

• SMP = thinner coating
• Plastisol = heavy-duty protection

14. Best Industries Using SMP Coated Steel

• Construction
• Industrial buildings
• Agriculture
• Commercial roofing
• Prefabricated structures

15. How to Choose SMP Coated Steel

Choose SMP When:

• Moderate to high outdoor exposure
• Better lifespan than PE required
• Roofing and cladding applications
• Balanced cost and performance needed

Avoid When:

• Extreme environments (use PVDF or Plastisol)
• Budget is very limited (use PE)

16. FAQ Section

What is SMP coated steel?

Steel coated with silicone modified polyester.

Is SMP better than PE?

Yes, it offers better durability and UV resistance.

How long does SMP last?

Typically 15–20 years.

Is SMP good for roofing?

Yes, widely used for roofing.

Does SMP crack during roll forming?

It can if bends are too tight.

17. Machine Matcher Section

We supply roll forming machines for all material types including SMP coated steel.

• Custom-built machines to your profile
• New machines built to specification
• Global delivery available
• UK and USA technical support

Contact:
Machine Matcher
Sales & Technical Team

Quick Specs

Thickness
0.25–1.2mm

Yield Strength
180–350 MPa

Coil Width
600–1250mm

Coil ID
508 / 610mm