SGCC, SGCD, and SGHC are continuously hot-dip galvanized steel grades defined by the Japanese standard JIS G 3302. They are produced by immersing steel sheet in a molten zinc bath (approximately 450°C) to form a metallurgically bonded zinc coating that provides both barrier and sacrificial corrosion protection.

SGCC (Steel, Galvanized, Cold-rolled, Commercial) is the commercial quality grade. It offers balanced mechanical properties with a minimum tensile strength of 270 MPa and minimum elongation of 22 percent. SGCC is suitable for general bending, shallow drawing, and simple forming. Typical applications include roofing sheets, wall cladding, HVAC ductwork, home appliance panels, and general structural components.

SGCD is the drawing quality grade, designed for deep drawing and complex forming. It is further divided into SGCD1 (drawing), SGCD2 (deep drawing), and SGCD3 (extra deep drawing) with increasing ductility. SGCD has a minimum tensile strength of 270 MPa and elongation ranging from 28 to 34 percent. Common uses include automotive inner panels, fuel tanks, washing machine drums, and parts requiring severe contouring.

SGHC is the structural grade, produced from hot-rolled steel that is subsequently galvanized. It has a minimum yield strength of 205 MPa and tensile strength of 270 MPa, with typical thicknesses from 1.6 mm to 6.0 mm. SGHC is used for load-bearing structural components, building frames, roofing systems for industrial buildings, machinery supports, and agricultural equipment.

All three grades are available with various zinc coating masses (e.g., Z08, Z12, Z18, Z27, Z35) from 80 to 600 g/m² total. Surface finishes include regular, minimized, or zero spangle, and treatments such as chromating, oiling, or dry finish. International equivalents: EN 10346 (DX51D+Z for SGCC, DX53D+Z for SGCD) and ASTM A653 (CS Type B, DDS).