The situation of screwed hanger rod breakage on costant force hanging bracket for main steam pipeline of 300 MW unit in one power plant has been presented.Through material quality inspection

fracture analysis

and breakage mechanics calculation

it shows that the quality and norm of said hanger rod are conform to the requirements of standard

the causes leading to breakage of the hanger rod are due to effects of abnormal tension+bending fatigue load

and being related to rotating shaft corrosion of the constant force hanging bracket.For this

it is recommented to conprehensively inspect the constant force hanging bracket

which has longer operation period and lowered performance

and being gradually replaced

to ensure safety of the pipeline system.