SPCC and SPHC are symbols used by the Japanese Industrial of Standards to define steel sheets. The main difference between these two types of steels is the method of production. SPCC refers to COLD rolled steel whereas SPHC refers to HOT rolled steel (with all that it means: Properties, grain size, etc).
SPCC and SPHC are grades of commercial steel referenced in the Japanese standard.
SPCC: Cold Rolled Carbon Steel Sheets and Strip
SPHC: Hot Rolled Mil Steel Plates, Sheets and Strip