Types of Steel
All of them are based on the Japanese Industrial Standard for flat steel.
SECC steel is electro galvanized commercial quality cold rolled steel which is basically cold rolled and then coated with zinc in an electro galvanizing line. SECC is a material grade and designation defined in JIS G 3313 standard.
A low-cost type of metal with high thermal conduction that is often used for computer cases.
SGCC steel is a soft forming quality hot dip galvanized steel. SGCC is a material grade and designation defined in JIS G 3302 standard.
JIS G 3302 is a Japanese material standard for hot dip galvanized steels. The commercial quality hot dip galvanized steel is a type of steel that can be made after galvanizing a coil of SPCC cold rolled material.
You will have a problem painting SGCC.
SPCC steel is a commercial quality cold rolled steel. SPCC is a material grade and designation defined in JIS G 3141 standard. As a basic Carbon Steel it can be enumerated in dead mild steel. What is JIS G 3141? JIS G 3141 is a Japanese material standard for cold rolled steel.