Handbook of Case Histories in Failure Analysis
Failure of a Reversible Flap Valve in a Thermal Power Station
-
Published:1993
Abstract
A reversible four-way carbon steel flap valve in a thermal power station failed after 7 years of service. The flap had been fabricated by welding two carbon steel plates to both sides of a carbon steel forging. The valve was used for reversing the flow direction of seawater in the cooling system of a condenser. Visual examination of the flap showed crystalline fracture, indicating a brittle failure. Metallographic examination, chemical analyses, and tensile and impact testing indicated that the failure was caused by the notch sensitivity of the forging material, which resulted in low toughness. It was recommended that fully killed carbon steel with a fine-grain microstructure be used. Redesign of the flap to remove the step in the forging that acted as a notch was also recommended.
K.K. Vasu, Failure of a Reversible Flap Valve in a Thermal Power Station, Handbook of Case Histories in Failure Analysis, Vol 2, Edited By Khlefa A. Esaklul, ASM International, 1993, p 267–270, https://doi.org/10.31399/asm.fach.v02.c9001353
Download citation file:
New Handbook: Volume 11B
Now available in the Digital Library! Volume 11B serves as a reference and guide to help engineers determine the causes of failure in plastic components and make corrective adjustments through design and manufacturing modifications.