Failure of boiler tubes 2

[0481]

We are carrying out root cause analysis of boiler tubes failure in which tubes severely bulged and expanded by reducing wall thickness,actual OD was 76.2 after expansion OD is 91mm.Best possible reason ?

 

[metengr]

Short term overheat (stress rupture) caused by total or partial blockage within the tube circuit.

 

[unclesyd]

Checkout the picture in the short term overheat section.

Keep in mind that it doesn't have to look exactly like this photograph. There can be any ammount of distortion as long as it looks like a "Fish Mouth".

http://www.babcock.com/pgg/tt/pdf/E1013153.pdf

 

[macmet]

That is a great link UncleSyd. I'll bookmark that one.

Cheers.

 

[0707]

overheating schema

long term overheating (on short term overheating the edges of the fish mouth are thinner)

creep schema

creep failure

luis marques

 

[kenvlach]

A 293-page book of material (with lots of color photos) as shown by 0707 and in unclesyd's link is
The NALCO Guide to Boiler Failure Analysis ISBN: 0070458731 (1990). "Description: This book illustrates and explains virtually all common failure modes which adversely affect boiler reliability. Each failure mode is well illustrated with case histories. The corrective steps necessary to reduce or eliminate each failure type, as well as precautionary notes, are provided. The book is a comprehensive, authoritative field guide for the identification and elimination of boilure failures. Boilers of virtually all pressures and many construction designs are presented."

http://used.addall.com/SuperRare/Re...or=&exDesc=&match=Y&&order=PRICE&ordering=ASC