Skip to Main Content

Abstract

An air compressor was installed at a chemical plant in which nitric acid was produced by burning ammonia with air. It was a 5000 hp, 5-stage centrifugal machine running at 6000 rpm, compressing air to 5 atm. Failure of the first stage impeller occurred due to a segment from the back plate becoming detached. On the remaining portion, cracks were visible running between the holes for rivets by which the vanes were attached. Metallographic examination of selected sections from the backplate revealed the material to be in the hardened and tempered condition, and the cracking to have initiated on the internal surface of the plate at the crevice between the plate and the vane. It was evident that the impeller failed by stress-corrosion cracking, which initiated in the crevice between the vanes and back plate and propagated through the plate along the line of the rivets where working stresses would be greatest. The compressor intake was situated in the vicinity of nitric acid pumps which had a history of leakage troubles, and which had evidently given rise to the nitrates found on the impeller.

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

2019. "Stress Corrosion Failure of Impeller of Centrifugal Air Compressor", ASM Failure Analysis Case Histories: Chemical Processing Equipment

Download citation file:


Close
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal