FIELD: screen cartridges of sections of heat insulation apparatuses used in ferrous metallurgy in roller tables of wide strip hot rolling mills. SUBSTANCE: cartridge includes housing and row of rectangular tubes, each tube is filled with heat insulator. All tubes are closed at their ends and they are closely fit onto rods secured to housing with possibility of placing cartridge in section while arranging tubes along roller table. In cartridge on contact-free horizontal wall of each tube there is lengthwise slit of predetermined width. Said slit embraces end walls of tube where its depth is at least equal to thickness of horizontal wall. Method for making lengthwise slit on tubes of cartridge comprises steps of forming slit on tubes closely fit onto rods. Invention provides possibility for using two horizontal tubular walls of cartridge. EFFECT: increased useful life period of cartridge. 3 cl, 4 dwg
