As a fundamental material in modern industry, the thickness standard of low-carbon steel sheet directly affects product performance, processing technology, and engineering safety. Based on national standards (GB), international specifications (such as ISO and ASTM), and industry practices, this article systematically reviews the thickness classification, tolerance requirements, application scenarios, and selection points of mild steel plate, providing a reference for engineering design, manufacturing, and procurement.
Note: These values are based on the standard density of mild steel ($approx 7850 kg/m^3$). Actual weights may vary slightly due to rolling tolerances.
1. Cold-rolled low-carbon steel plate Thickness range: 0.3mm~3.5mm (GB/T 5213-2019), some special processes can extend to 0.2mm (such as DC06 grade for deep drawing).
Features: High surface quality (Ra≤3.2μm), strict dimensional accuracy (tolerance ±0.05mm~±0.3mm), suitable for precision forming applications such as automobile bodies and appliance housings.
2. Hot-rolled low-carbon steel plate Thickness range: 1.2mm~60mm (GB/T 709-2019), of which:
Thin plates (1.2~3mm): used for building roof trusses, bridge supports, etc.;
Medium-thick plates (3~25mm): suitable for engineering machinery bases, ship bulkheads;
Thick plates (>25mm): used for mining equipment, pressure vessels.
3. Pickled low-carbon steel plate. Thickness range: 0.3mm~6.0mm (ASTM A1008). The oxide scale is removed by pickling, and the surface roughness Ra is controlled at 0.6~1.9μm. It is suitable for high corrosion resistance applications (such as chemical pipelines).
The Metric Formula (Kilograms)
To find the weight of a plate in kilograms, use the following equation:
Weight (kg) = Length (m)*Width(m) * Thickness(mm) *7.85
The Imperial Formula (Pounds)
To calculate weight in pounds using inches:
Weight(lb) = Length(in) * Width (in) * Thickness(in) * 0.2836
Always factor in a ±0.2mm to ±0.5mm variance for precision engineering to avoid fitment issues in assemblies.
Standard Mild Steel Plate Thickness Chart
Mild steel is typically classified as a "sheet" if it is thinner than 3mm and a "plate" if it is 3mm or thicker. Below is the standard conversion and weight reference for common MS plate sizes.| Thickness (mm) | Thickness (inches) | Approx. Weight (kg/m2) | Approx. Weight (lb/ft2) |
| 1.6 mm | 0.063" | 12.56 | 2.57 |
| 2.0 mm | 0.078" | 15.7 | 3.22 |
| 3.0 mm | 0.118" | 23.55 | 4.82 |
| 5.0 mm | 0.197" | 39.25 | 8.04 |
| 6.0 mm | 0.236" | 47.1 | 9.65 |
| 8.0 mm | 0.315" | 62.8 | 12.86 |
| 10.0 mm | 0.394" | 78.5 | 16.08 |
| 12.0 mm | 0.472" | 94.2 | 19.29 |
| 16.0 mm | 0.630" | 125.6 | 25.72 |
| 20.0 mm | 0.787" | 157 | 32.15 |
| 25.0 mm | 0.984" | 196.25 | 40.19 |
Note: These values are based on the standard density of mild steel ($approx 7850 kg/m^3$). Actual weights may vary slightly due to rolling tolerances.
Low-carbon steel plate thickness classification system
Low-carbon steel plates can be classified into the following categories according to production process and thickness range:1. Cold-rolled low-carbon steel plate Thickness range: 0.3mm~3.5mm (GB/T 5213-2019), some special processes can extend to 0.2mm (such as DC06 grade for deep drawing).
Features: High surface quality (Ra≤3.2μm), strict dimensional accuracy (tolerance ±0.05mm~±0.3mm), suitable for precision forming applications such as automobile bodies and appliance housings.
2. Hot-rolled low-carbon steel plate Thickness range: 1.2mm~60mm (GB/T 709-2019), of which:
Thin plates (1.2~3mm): used for building roof trusses, bridge supports, etc.;
Medium-thick plates (3~25mm): suitable for engineering machinery bases, ship bulkheads;
Thick plates (>25mm): used for mining equipment, pressure vessels.
3. Pickled low-carbon steel plate. Thickness range: 0.3mm~6.0mm (ASTM A1008). The oxide scale is removed by pickling, and the surface roughness Ra is controlled at 0.6~1.9μm. It is suitable for high corrosion resistance applications (such as chemical pipelines).
How to Calculate Mild Steel Plate Weight
If you have a custom size, you can calculate the weight manually. Accurate weight calculation is vital for determining shipping costs and crane load requirements.The Metric Formula (Kilograms)
To find the weight of a plate in kilograms, use the following equation:
Weight (kg) = Length (m)*Width(m) * Thickness(mm) *7.85
The Imperial Formula (Pounds)
To calculate weight in pounds using inches:
Weight(lb) = Length(in) * Width (in) * Thickness(in) * 0.2836
Understanding Tolerance Ranges
It is a common misconception that a "10mm plate" is exactly 10.00mm. According to international standards like ISO 9445 or ASTM A6, plates have "rolling tolerances." A 10mm plate might arrive at 9.8mm or 10.2mm depending on the mill's precision.Always factor in a ±0.2mm to ±0.5mm variance for precision engineering to avoid fitment issues in assemblies.
