Abstract:The hydride orientation factor has great influence on the mechanical properties and service performance of the fuel cladding tube during the nuclear reactor operation. The straightening experiment was carried out by using 6-roll precision tube straightener, the influence of roll gap, bending and straightening roller angle on the hydride orientation of Zr-Sn-Nb alloy pipe with ?10 mm was studied. The residual stress of the straightened sample was analyzed by X-ray diffraction technique, the hydride distribution of autoclave hydrogenated samples was observed by optical microscope, the hydride orientation factor(Fn~(40°))was detected by rating software. The results show that roll gap, bending and angle of straightening roller have significant influence on the residual stress of pipe after straightening, the hydride orientation factor increases with the increase of residual stress. When the roll gap is greater than or equal to 10 mm, the bending less than or equal to 4.2 mm,and the angle of straightening roller is between 31.5°and 33.5°, the residual normal stress is less than or equal to 35.6 MPa, shearing stress is less than or equal to 37.8 MPa. The hydride orientation is circumferential or near circumferential, hydride orientation factor to meet the technical requirements.