When specifying a steel container frame, the anti-rust treatment of the corner blocks deserves close attention. The beams and columns are made from galvanized steel and receive an additional powder coating, which makes them hard to rust. However, the container corner is welded from steel plate, and that welded area behaves differently from the rest of the frame.

With a standard powder coating only, the coating may not fully cover every welding point on the corner. In practice, this can leave exposed areas that begin to rust within about half a year. For buyers sourcing ship container frames 20ft, this is a detail worth confirming with the supplier before ordering, because corner condition affects the long-term appearance and maintenance needs of the frame.

To address this, the container corner is electroplated first and then powder coated. This two-step process is designed so the corner will not get rusted. If you are evaluating a frame container knock down option, ask the supplier to explain how the corners are treated and whether electroplating is included before the powder coating stage.

Because the corner is a welded assembly, the quality of the anti-rust treatment depends on both the electroplating and the powder coating being applied correctly. Buyers should request close-up photos of the corners and confirm the treatment sequence with the supplier. This helps ensure the delivered steel container frame meets expectations for rust resistance in the intended environment.