FABRICATION METHOD OF LONG HOLLOW SHIP'S SHAFTS OF LARGE AND MEAN DIAMETRES FROM LOW-MAGNETIC CORROSION-RESISTANT STEELS Russian patent published in 2010 - IPC B21B21/00 

FIELD: metallurgy.

SUBSTANCE: method involves manufacture of ingots in electric or open-hearth furnaces by using treatment with molten synthetic slag in ladle, repair of ingots, their heating to ductility temperature, forging on presses into long crude workpieces with thickened one or two ends, mechanical processing along external surface and drilling of central hole with further boring and grinding to specified geometrical dimensions; at that, cylindrical crude thick-walled tubes-workpieces for fabrication of long hollow ship's shafts of large and mean diametres from low-magnetic corrosion-resistant steels are made by rolling on pilger mills, which are rerolled on mills HPT 450 or HPT 250 into cylindrical tubes-workpieces of the required length depending on the diametre; end sections of cylindrical tubes-workpieces are heated in one-coil moving induction block up to 950-1050°C; upsetting of thickening on the holder on one or both ends is carried out on the upsetting machine in several passes with local repair of surface or by continuous rough machining of thickening on intermediate size; mechanical treatment of thickened ends is performed with their further grinding as to the specified geometrical dimensions; at that, the first pass of the upsetting is performed at minimum transmission ratio. Geometrical thickening parametres are determined from the specified relationships.

EFFECT: reducing labour input and coefficient of metal consumption during fabrication of ship's shafts, and reducing their cost.

2 cl, 2 tbl