Corrosion of Flue Gas Sensor in Boiler Stack

A commercial gas velocity sensor used for flue gases monitoring was subject to severe corrosion failure. A combination of mechanisms was proposed including a dominating 5 severe dew point corrosion for both transducer and its covering, galvanic attack and an eventual hydrogen attack for the transducer side part. Recommendations were proposed to avoid a future severe damage to such type of sensor including an insulation between transducer and covering metals and an up-grade of the titanium alloy used.

More information : sciencedirect.com/science/article

Corrosion cracking of 304L stainless steel pipe clamps

Case study of stainless steel components of a geothermal heating system failed prematurely. The crack surfaces were brittle in appearance and were predominately transgranular. The failure was determined to be caused by chloride induced stress corrosion cracking. Subsequent failures may be avoided by informed alloy selection.

More informations : Transgranular stress corrosion cracking of 304L stainless steel pipe clamps in direct use geothermal water heating applications.

Fatigue cracking of high pressure oil tube

  • High pressure pipe failed by fatigue in the fusion line of longitudinal weld.
  • Fatigue was caused by vibration of the line due to clamp missing.
  • Crack initiated and propagated through the high concentration region of weld joint.
  • Change of specified material (UNS S31803) by AISI 304L contributed to the failure.
  • As recommendation, seamless tube of duplex stainless steel must be used.

More informations : Fatigue cracking of high pressure oil tube.

Failure Analysis of Rocker Liner used as a charging system of Blast Furnace

In this study, failure analysis of rocker liners used for charging system of Blast Furnace was carried out. The failed rocker liner samples shows non-uniform distribution of carbides, resulted in variation of hardness as well as wear properties. After proper heat-treatment and chemistry modification, the Rocker Liner obtained high hardness (with uniformity) due to proper distribution of carbide phases in the tempered martensitic matrix. Thus proper heat treatment is needed to achieve optimum property with changing the material composition to deal with this stringent working condition. Rocker liner with modified microstructure was trailed in the Blast Furnace and it has given a life of around 20-22 months life.

More informations : Failure Analysis of Rocker Liner used as a charging system of Blast Furnace.

Failure Analysis on antistatic coatings on Radome

The damage of the inelastic coating was more serious than the elastic coating. The failure causes of the antistatic coating on the radome were analyzed. The results show that the failure of inelastic and elastic antistatic coatings was caused by particles erosion, and the aging of the coatings accelerated the failure of coatings. The elastic coating had better anti-erosion ability than the inelastic coating because of its high fracture elongation and good elastic deformation, so its damage was lighter than the inelastic coating.

More informations : Failure Analysis on antistatic coatings on Radome.

Case Studies in Engineering Failure Analysis

It is with great pleasure that I write the first editorial for Case Studies in Engineering Failure Analysis. (Richard Clegg)

We believe that the journal fills an important niche in the market. Other professions such as medicine and the law make great use of case studies, but engineers have not really formalised this to the same extent. It may be that our education tends to lead us to the view that all problems can be solved based on “First Principles” or through a program of rigorous scientific experimentation. But it has long been my belief that an enormous amount can be gained by studying how things behave in practice, and there is no better teacher than failure.

more : Case Studies in Engineering Failure Analysis.

Erosion-Corrosion Behavior and Failure Analysis of Offshore Steel Tubular Joint

Capture electrochemsci vol8A new publication of the International Journal of Electrochemical ScienceMay 1, 2013  

An extensive investigation into the erosioncorrosion behavior and failure analysis of an offshore steel tubular joint has been carried out by various electrochemical techniques, visual inspection, optical microscope examination, mechanical testing, microstructure examination, chemical analyses, Scanning Electron Microscope (SEM) examination, Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD).

For further informations click : www.electrochemsci.org/papers/vol8/80507187.pdf

Failure analysis of conveyor pulley shaft

Via Sciencedirect.com : A failure analysis was performed on the shaft of a conveyor belt drive pulley. The shaft failed after seven days in service. Failure mechanism was high cycle fatigue. Failure occurred due to improper reconditioning of the shaft.

Failure Analysis of a Rubber Hose in Anhydrous Ammonia Service

In July 2009, a fiber-reinforced rubber hose ruptured while being used to transfer liquid ammonia from a cargo tank truck to a storage tank. The rupture released ammonia vapor that drifted across a highway and through a neighborhood. As a result, one person was fatally injured and seven others required medical treatment.

This case history presents the failure analysis of the ruptured fiber-reinforced rubber transfer hose and focuses on the techniques used in the investigation. In particular, this case demonstrates how fractography can be applied to reinforced rubber and how Fourier transform infrared spectroscopy can be used to determine ammonolysis failure of fiber-reinforcement polymers.

via : ScienceDirect.com – Case Studies in Engineering Failure Analysis – Failure Analysis of a Rubber Hose in Anhydrous Ammonia Service.

Hydrogen embrittlement failure of box-like link-plate

This paper present a failure analysis of box-like link-plate. The failed link-plate is fabricated from 42CrMo steel and the surface of internal hole is demanded to be induction-hardened.

Evidences indicate that the failure of link-plate is due to hydrogen. The possible source for hydrogen was introduced during melting and casting process. A great number of non-metallic inclusions in the link-plate material acted as traps of hydrogen.

Via : http://www.sciencedirect.com/science/article/pii/S1350630713000617