FIELD: mechanical engineering. SUBSTANCE: apparatus has upper and lower plugs mounted on core ends with forming members shaped as ribs extending along core axis. Lower plug is rigidly coupled with core and upper plug is coupled with core by threaded connection and provided with channel for discharging air from shell cavity. Tubular article and pressing shell with core and plugs at core ends are placed in sleeve provided with cover having working fluid supply opening. Working fluid pressure disturbs radial stability of shell, which is collapsed along its length in accordance with core rib shape. When pressure is relieved and apparatus is dismantled, collapsed shell is easily withdrawn from article cavity. EFFECT: increased efficiency and enhanced reliability in operation. 2 dwg
