Method for producing an improved yankee cylinder

Method for producing a Yankee dryer cylinder comprising the steps of:

• executing a cylindrical tubular semifinished product made of steel having a side wall provided with an internal surface and an external surface;
• forging said cylindrical tubular semifinished product for obtaining a cylindrical tubular semifinished product having enlarged terminal portions and comprising a first predetermined thickness s1 at a central portion of said side wall and a second predetermined thickness s2, with s2>s1, at the end of the opposite terminal portions of said side wall;
• executing a plurality of grooves at said internal surface of said cylindrical tubular semifinished product, thus obtaining a cylindrical shell of said Yankee dryer cylinder;
• executing a plurality of longitudinal blind holes at an external surface of said enlarged terminal portions of said cylindrical shell;
• positioning a head at each enlarged terminal portion of said cylindrical shell, each head being provided with a plurality of through holes, at the end of said positioning step each through hole of said plurality being aligned with a respective blind hole of said enlarged terminal portion of said cylindrical shell;
• fixing each of said head to a respective enlarged terminal portion of said cylindrical shell by screwing a stud to each couple of aligned blind holes and of through holes.