FIELD: extrusion of tubes of thermoplastic materials. SUBSTANCE: method comprises steps of extruding tube of thermoplastic material; cooling it by means of first cooling device arranged behind extruder until temperature of orientation of thermoplastic material; mounting tube onto mandrel at orientation temperature at applying traction effort to tube by means of traction mechanism arranged after mandrel for overcoming resistance at mounting tube onto mandrel. Mandrel is stationary secured to extruder by means of tensioning member and it includes expanding section that forms bulge along tube circumference. Tube is cooled in addition by means of second cooling unit arranged after expanding section of mandrel. Resistance that counteracts tube mounting onto mandrel is controlled along tube circumference with the aid of row of separately operated resistance control units arranged near mandrel. EFFECT: possibility of making tube with constant thickness of wall and constant double-axis orientation. 8 cl, 3 dwg
