Seat board of foldable chair and bottom frame thereof

A seat board of a foldable chair, comprising:

• a panel, and
• a bottom frame, wherein:
• the bottom frame is formed by bending a metal material sheet, has a rectangular shape, and has smooth transitions on four corners,
• a top portion of the bottom frame is bent to form an annular inner blocking edge and an annular outer pressing edge,
• an annular installation groove having an upper opening is formed between the annular inner blocking edge and the annular outer pressing edge,
• four sides of the panel form an annular folded-downward edge folded downward,
• the annular folded-downward edge is inserted into the annular installation groove from top to bottom,
• the annular inner blocking edge cooperates with the annular outer pressing edge to clamp and secure the annular folded-downward edge,
• two elongated sliding slots extending in a front and rear direction and configured for two T-shaped rivets to slide are symmetrically located on an outer side edge of a left side of the bottom frame and an outer side edge of a right side of the bottom frame,
• first ends of the two elongated sliding slots comprise enlarged holes into which caps of the two T-shaped rivets are configured to be inserted from outside,
• widths of the caps of the two T-shaped rivets are greater than widths of slot openings of the two elongated sliding slots and are smaller than widths of the enlarged holes, and
• two rivets for pivotally connecting to chair legs of the foldable chair are installed at positions of the enlarged holes after the two T-shaped rivets are inserted into the two elongated sliding slots.