Particularities of ensuring the precision of filaments from 12H18N9T steel for additive manufacturing at their fabrication

The issues of ensuring the accuracy of the filaments’ production for additive manufacturing using the electron beam energy at the stage of drawing of a workpiece made of 12H18N9T steel were considered. The reduction ratio varied in the range from e = 5 % to e = 67.5 %. Calculations showed that the dimensions of a workpiece for producing filaments with a diameter of O 1.3-0.09 mm was limited by O 4.27-0.17 mm. It was experimentally established that the diameter of a filament made of 12H18N9T steel after the last reducing step (1.3 mm) exceeded the allowable diameter (1.3−0,09 mm) and equaled to 1.37 mm. This deviation is probably induced by elasto-plastic strains occurring in the wire in the drawing process. To provide the required accuracy of the filaments with a diameter of O 1.3-0.09 obtained by drawing of 12H18N9T steel, it was recommended to grin the diameter of a die taking into account the magnitude of the elastic deformations, i.e. provide the diameter 0.05 mm smaller than required.