Choose right semi-trailer floor to avoid pitfalls

Choose right semi-trailer floor to avoid pitfalls

1. Standard Plate: Standard plate generally refers to ordinary carbon structural steel with a yield strength of approximately 235 MPa, designated Q235. Standard plate has low mechanical strength (softness) and is prone to denting and deformation. It also has poor corrosion and wear resistance, but it welds well and is not prone to cracking. To prevent severe denting and deformation, the thickness of standard semi-trailer floor plates is typically 2.0 mm or thicker. Depending on the application, the floor plates are available in either flat or patterned finishes.

2. Manganese Plate: Manganese plate is a low-carbon alloy structural steel with a yield strength of approximately 345 MPa, designated Q345, also known as 16 manganese steel. Manganese plate offers superior strength, wear resistance, and corrosion resistance to standard plate, and its weldability is similar to standard plate. Semi-trailer manganese plate floor plates are typically at least 1.8 mm thick. Depending on the application, the floor plates are available in either flat or patterned finishes.

3. High-strength plate: High-strength plate refers to low-alloy, high-strength steel with a yield strength of 345 MPa or higher. Key grades include Q390, Q420, Q460, Q510, Q550, Q610, and Q700. Higher grades indicate greater strength and surface hardness, making the material less susceptible to deformation and denting and more wear-resistant. However, as the grade increases, the material becomes more brittle (and less ductile), resulting in poor weldability and increased cracking. Currently, semi-trailer high-strength floor plates come in thicknesses of 1.2mm, 1.4mm, 1.5mm, 1.6mm, and 1.8mm. Due to the brittleness of high-strength plate, patterns cannot be applied, so trailer high-strength floor plates are typically flat.

4. Weight characteristics: For example, a 13-meter semi-trailer with a 2.0mm patterned floor plate weighs approximately 530 kg, while a 2.0mm flat floor plate weighs approximately 490 kg (reducing the flat floor plate thickness by approximately 0.1mm reduces the weight by approximately 25 kg). Because high-strength plate has a slightly higher density than standard plate, it weighs slightly more than standard plate of the same thickness. The difference for a 13-meter semi-trailer is approximately 10 kg.

5. Cracking and Welding Characteristics: Standard plate has good plasticity and weldability, and the welded area is less susceptible to thermal influence, making weld cracks less likely. However, it is prone to denting and deformation, so its thickness needs to be 2 mm or greater, which increases its weight accordingly. High-strength plate, despite its high strength, is brittle and sensitive to welding heat, making it prone to cracking at welds and poor weldability. However, high-strength plate exhibits excellent wear resistance, corrosion resistance, and deformation resistance, and is lightweight. Under current welding process conditions, for high-strength plate 1.5 mm or less, the risk of cracking at the weld increases by 35% for every 0.1 mm reduction in thickness.