The outer arc of eight elbow bent pipes in a two-stage desuperheater of the superheater for boiler no.4 in Yunfu Power Plant had been seriously flattened

after circularity measurement

thickness measurement

and non-destrutive inspection of said elbow bent pipes

on the basis of GB 9222-88 《Strength calculation of pressurized parts for water tube boilers》

and DL / T 5054-1996 《Technical specifications for designing steam-water pipelines in thermal power plants》

the thickness of the said elbow bend pipes has been calculated for verification respectively

as well as structural stress and film stress of them being computed by using finite element method. Based on synthesizing various results of measurement

inspection

and calculation

it is believed that the said eight elbow bend pipes can still be safe and reliable in operation at present.