Abstract: Discussed here in the essay are the main alloy elements as added into the X80 mother tube for the bend,and the effects thereof. Also elaborated are some current typical problems of the X80 heavy wall mother tube for the bend as often encountered with during the manufacturing process and the mechanical property testing process,including the post-heating over-standard diameter-reduction and the yield ratio,and non-conformance of the welding HAZ impact energy of the mother tube,etc. And main causes for the said problems are analyzed,based on which specific solutions are put forward,including properly enlarging the mother tube OD,expanding the hot bend,accepting the mother tube via the thermal simulation test verification method,and welding the mother tube with the low heat input or multilayer,and multipass welding methods.