ALUMINUM 5357 is an aluminum-magnesium-manganese alloy of the non-heat-treatable type. Formerly known as Aluminum C57S or Aluminum K157. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear and bearing strength. It also includes information on as well as forming, machining, and joining. Filing Code: Al-30. Producer or source: Aluminum Company of America.