Abstract: It is known that the angle of elevation of the extrusion roll shaft is responsible for the weld seam quality in a rather large extent. Mechanism for formation of the elevation angle of the extrusion roll shaft during manufacture of weld tubes is analyzed, and based on the analysis a proposal is put forward that a depression angle of the extrusion roll shaft be first formed to offset the elevation angle, and reference values of such depression angles for Φ76mm mill and Φ165mm mill are given on actual operation basis.