The typical microstructural characteristics of hot rolled stainless steel coil are:

1. Austenitic Microstructure: Hot rolled stainless steel coil, such as AISI 304 or 316 grades, typically has an austenitic microstructure. Austenite is a face-centered cubic (FCC) crystalline structure of iron and alloying elements like chromium and nickel.

2. Grain Structure: The grains in hot rolled stainless steel are elongated in the rolling direction due to the deformation during the hot rolling process. The grain size is generally coarser compared to cold rolled or annealed stainless steel.

3. Inclusions and Precipitates: Hot rolled stainless steel may contain non-metallic inclusions, such as oxides, sulfides, or silicates, that were present in the original steel composition or formed during the steelmaking and hot rolling processes. Precipitates of carbides or intermetallic compounds may also be present, depending on the stainless steel grade and processing conditions.

4. Deformation Substructure: The hot rolling process introduces a deformation substructure within the grains, characterized by the formation of dislocation cells, subgrains, and deformation twins. This substructure contributes to the overall strength of the hot rolled stainless steel.

5. Residual Stresses: Residual stresses can be present in the hot rolled stainless steel coil, primarily compressive stresses on the surface and tensile stresses in the core, due to the thermal and mechanical processing during hot rolling.

6. Texture: Hot rolled stainless steel generally exhibits a rolling texture, with the preferred orientation of the grains aligned in the rolling direction. This texture can influence the mechanical properties, such as anisotropy, of the material.

The specific microstructural characteristics may vary depending on the stainless steel grade, the hot rolling parameters (temperature, reduction, cooling rate), and any subsequent heat treatments or processing steps.