If the material in the corner post is unknown, what type of steel should be used for replacement?

Using high-tensile carbon or Corten steel for replacement in the corner post is a suitable choice due to their strength and durability properties. Corner posts in containers are subjected to significant loads and structural forces, so using a material that can withstand these conditions is critical.

High-tensile carbon steel is known for its superior strength compared to low-carbon steel, making it an ideal replacement for maintaining the structural integrity of a container. Corten steel, also known as weathering steel, possesses corrosion resistance which is particularly beneficial in harsh environments, enhancing the lifespan of the container. Given these attributes, these materials are preferable when the original material is unknown, as they provide the necessary mechanical properties and durability required for such applications.

In contrast, alternatives like aluminum or low-carbon steel may not offer the same level of strength and durability, making them less suitable for the demanding structural roles that corner posts fulfill. Stainless steel, while robust, is often more expensive and may not be necessary for this application unless corrosion resistance is a primary concern. Plastic composite materials, although lightweight and resistant to corrosion, do not typically possess the structural strength required for load-bearing components like corner posts in containers.