Bendability Basis
S355J2W's carbon content is strictly controlled at ≤0.17%, and it contains alloy elements such as Mn, Ni, and Al that optimize toughness. This gives it excellent cold forming performance: the elongation rate can reach 22% or more, and the impact toughness at -20°C is not less than 27 J. These properties ensure that the steel plate will not produce brittle cracks or large-area deformation damage during the bending process.
Detailed Bending Process RequirementsBending radius control:
For steel plates with a thickness of ≤6mm, the minimum bending radius can be controlled at 1 times the plate thickness, which can meet the needs of most small-radius bending scenarios such as decorative components
For steel plates with a thickness of 6-15mm, the minimum bending radius needs to be adjusted to 1.5-2 times the plate thickness, to avoid excessive stress concentration on the inner side of the bending part
For steel plates with a thickness of >15mm, it is recommended to set the minimum bending radius to 2.5-3 times the plate thickness, and preheat the bending area to 100-150°C before processing, which can further improve the ductility of the local area and reduce the risk of surface cracking
Surface protection during processing:
During the bending operation, it is necessary to avoid using hard tools to scratch the surface of the steel plate. If the mature patina is accidentally damaged, the exposed fresh steel will quickly start the oxidation reaction, and the alloy elements (Cu, Cr) in the steel will migrate to the damaged area, forming a new patina layer to complete self-repair within 1-4 weeks, without affecting the overall corrosion resistance
Post-bending treatment:
After bending, there is no need for additional heat treatment. The residual stress generated by bending will not affect the structural strength and corrosion resistance of the steel plate, and will gradually decrease during the natural weathering process
Performance Changes After Bending
Bending will only cause local plastic deformation of the steel plate, and will not change the internal microstructure and alloy composition of S355J2W. Therefore, the core mechanical properties (yield strength ≥355 MPa, tensile strength 470-630 MPa) and the self-healing ability of the patina will not be affected. The patina on the bending part can still form and maintain a stable protective effect normally, and the bending part can still meet the long-term use requirements of outdoor structures
