Products tagged with 'failure investigation'

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Failure of Cast Duplex Stainless Steel Valves Due to Improper Microstructure

Product Number: 51324-20759-SG

Author: K. Ravindranath; B. Al-Wakaa; A. Ali; Ahmad Al-Swaha; Salem Al-Qahtani

Publication Date: 2024

$40.00

Cast duplex stainless steels are popularly used in the petroleum industry due to their good corrosion resistance and mechanical properties. One of the applications of cast duplex stainless steels in the petroleum industry is in the manufacture of valves in corrosive service. The good properties of duplex stainless steels are attributed to their balanced microstructure containing austenite and ferrite phases. The balanced microstructure in the duplex stainless-steel components is achieved by the optimum heat treatment and manufacturing process. Improper cooling during manufacturing or accidental exposure of the component to high temperatures can induce the precipitation of secondary phases in the microstructure of duplex stainless steel, which can seriously influence the corrosion resistance and mechanical properties. The paper deals with the failure investigation of the first-generation cast duplex stainless steel valves that failed in a short duration of service. The microstructure of the failed valve was characterized by optical and scanning electron microscopy. The effect of the microstructure on the mechanical properties was assessed by hardness measurements, tensile testing, and impact toughness testing. The study indicated that the properties of the duplex stainless-steel valves were affected due to the precipitation of secondary phases and the root cause of the failure was embrittlement caused by the precipitated secondary phases.

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Using Forensic Science to Determine Causes of Failures of Polymeric Coatings

Product Number: 41215-875-SG

Author: Jon Asselanis

Publication Date: 2015

$20.00

Often when a polymeric flooring system fails, the cause of the problem is unknown. Forensic testing is used to determine the cause of failure while eliminating other potential causes. A basic understanding of the approach to a forensic investigation and the types of testing used will help aid in correcting the problem so future failures and project costs are reduced.

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Weld Jointing Influence on Boiler Tube Sheet Integrity

Product Number: MPWT19-14366

Author: Sameer Ayyar, Mahmood Al-Ridy, Farhat Choudhary, Adi Alammari, Itoro Akrasi

Publication Date: 2019

$0.00

Boiler system is one of the most critical systems for a utility plant. A utility plant had experienced high percentages of boiler downtime owing to boiler tube sheet cracking failures. Investigations carried out revealed high stress at the tube-to-tube sheet joint in the boiler fire-side entrance. Tube-to-tube sheet joints at the boiler fire-side entrance had been fabricated by strength welding and without any expansion. The strength welded joint had created undue stress leading to cracking of the weld joint by thermal expansion. A higher quality expanded joint consisting of expanding, flaring and seal welding the fire-side entrance was implemented during the re-tube process. The utility plant has now zero downtime due to boiler tube failure. This article summarizes the description and history of failures with the boiler at the utility plant; investigations and corrective actions carried out; and the present improved condition of the boilers.

Products tagged with 'failure investigation'

Failure of Cast Duplex Stainless Steel Valves Due to Improper Microstructure

Using Forensic Science to Determine Causes of Failures of Polymeric Coatings

Weld Jointing Influence on Boiler Tube Sheet Integrity

Association for Materials Protection and Performance