Skip to Main Content

Abstract

A superheater in a generator produced 80 t/h of steam at 400 deg C and 41 kPa. Failure took place at the connection from the collector to the vent line used during start up. The material of construction was carbon steel, and the unit had 240,000 h of operation at the time of failure, with 99 shutdowns. Widespread cracking on the inside was apparent, the most severe cracking being some distance from the nozzle connection in a downstream direction. Widespread cracking and pitting were observed also at the connections to the safety valve and soot blower. Pitting was most apparent on the downstream sides of the openings in the shell. In all the damaged areas the mechanism of failure involved surface pitting and subsequent SCC. This failure showed the problems that can develop where there are long lines in which condensation may occur and return periodically to a superheater or other hot component. In this particular case, control of dissolved solids in the boiler feedwater may have been inadequate.

You do not currently have access to this chapter.
Don't already have an account? Register

T.L. da Silveira, I. Le May, 2019. "Failure at a Steam Outlet Collector", ASM Failure Analysis Case Histories: Power Generating Equipment

Download citation file:


Close
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal