Sheet Metal Material Selection Guide for Engineers
_
Selecting the right material for sheet metal parts is crucial for ensuring structural performance, manufacturing efficiency, and cost-effectiveness. This guide outlines preferred materials such as SPCC, SECC, stainless steel, aluminium, and copper, and offers insights into thickness recommendations, surface treatments, and application considerations.
Best Materials for Sheet Metal Parts
2.1 Cold Rolled Steel Plate (SPCC)
- Common Thicknesses: Refer to standard guidelines.
- Surface Treatments: Colour zinc plating, blue zinc plating, nickel plating, powder coating.
- Applications: Ideal for parts requiring welded assembly; apply electroplating or powder coating afterward.
2.2 Electrogalvanised Steel Sheet (SECC)
- Common Thicknesses: As per standard specifications.
- Surface Treatments: Generally untreated. Use silver paint for rust-prone areas. Powder coating is recommended for visible surfaces.
- Applications: Best for non-welded or minimally welded parts. Helps reduce production costs and processing time.
2.3 Aluminium-Zinc Coated Steel Sheet
- Common Thicknesses: Same as SECC.
- Surface Treatments: Typically untreated. Use silver paint on exposed edges; powder coating for visible applications.
- Applications: Suitable for parts where both corrosion resistance and cost-efficiency are priorities.
2.4 Stainless Steel for Sheet Metal
- Grades: SUS304, ICr18Ni9Ti, SUS316 (for parts exposed to acidic or alkaline environments).
- Common Thicknesses: Follow standard guidelines.
- Surface Treatments:
- Passivation
- Black oxide
- Electropolishing
- Pre-treated finishes such as:
- SUS304 HL (hairline)
- SUS304 BA (matte)
- SUS304 Mirror (mirror finish)
- Applications: Ideal for parts requiring high corrosion resistance or premium surface appearance.
2.5 Aluminium Sheet for Enclosures and Components
- Grades: 1100 (pure aluminium), 5052, 6061 (aluminium alloys)
- Standard Thicknesses: As specified in the guideline.
- Surface Treatments:
- Brushed anodising (black or white)
- Sandblasted anodising (not recommended due to deformation risks)
- Powder coating
- Conductive anodising (light yellow, chemical process) for parts requiring electrical conductivity
- Applications: Commonly used for lightweight, corrosion-resistant parts and electrical enclosures.
2.6 Copper Sheet (H62)
- Thickness: Typically 2.0 mm
- Surface Treatments: Nickel plating, black oxidation, or none.
- Applications: Used for parts requiring high conductivity or a decorative finish.
Common Sheet Metal Materials
Comparison table based on mechanical properties, corrosion resistance, surface finish, and suitability for production.
| Material Type | Grade/Specification | Standard Thickness (mm) | Surface Treatments | Recommended Applications |
| Cold Rolled Steel | SPCC | 0.8 – 2.5 | Colour zinc, blue zinc, nickel, powder coated | General structural parts |
| Electrogalvanised Steel | SECC | 0.8 – 2.5 | None (silver paint/powder coating optional) | Non-welded or lightly welded parts |
| Aluminium-Zinc Coated | – | 0.8 – 2.5 | None (silver paint/powder coating optional) | Parts needing moderate corrosion resistance |
| Stainless Steel | SUS304, SUS316 | 0.8 – 2.5 | Passivation, black oxide, electropolishing | Corrosion-resistant and decorative components |
| Aluminium | 1100, 5052, 6061 | 0.8 – 2.5 | Anodising, powder coating, conductive finish | Lightweight and conductive parts |
| Copper | H62 | 2 | Nickel plated, black oxide, untreated | Electrical parts and connectors |
Sheet Metal Design Considerations
3.1 Sheet Metal Thickness Recommendation
- Minimum recommended: 0.8 mm
- Maximum recommended: 2.5 mm
- Avoid 0.5 mm SPCC due to poor dimensional stability after bending or welding.
- Avoid sheets thicker than 2.5 mm due to difficulty in processing and bending.
3.2 Surface Treatment for Sheet Metal
- Ensure appropriate treatments are selected based on part visibility, corrosion resistance, and electrical conductivity requirements.
3.3 Cost-Effective Material Selection
- Choose materials that minimise variety and meet performance needs.
- SPCC vs SECC: SPCC is preferred for welded assemblies; SECC is ideal for non-welded parts.
- Stainless steel and aluminium are recommended for corrosion-resistant metal sheets or high-end applications.
