From the National Archives of South Africa http://www.national.archsrch.gov.za/ the descriptions of the said Associations Flags.
South African Infantry Association/Suid Afrikaanse Infanteriebond, Flag registrated by the South African Bureau of Heraldry on 25 March 1994:
"Flag: A rectangular flag with proportion 4:3, consisting of three horizontal stripes of equal width, from top to bottom green, black and green, charged in the centre with two white bayonets in saltire ensigned of a yellow springbok head caboshed, which surmounts all three stripes."
South African Armoured Association/Suid Afrikaanse Pantserbond, Flag registrated by the South African Bureau of Heraldry on 29 July 1994:
"Flag: A rectangular black flag in proportion 4:3, charged in the centre with the badge of the South African Tank Corps from 1942, viz a representation of a Mark V tank, also known as the Big Willie, therebeneath a riband bearing the motto ONS IS, all within a laurel wreath, charged at the top with a roundel bearing a springbok head, all white."