A case study published in « Case Studies in Engineering Failure Analysis« , july 2013.
A high chromium (HiCr) iron work roll broke in three pieces in finishing stand 4 in a compact strip production (CSP) mill of a steel company. The paper describes the causes of the roll failure manufactured from high chrome grade steel along with the precautionary measure.
A paper published in « Case Studies in Engineering Failure Analysis« , july 2013
The present work reports an investigation of a failure in a blade in the LP stage of a thermal power plant of 310 MW. After opening the turbine casing, one blade in the LP region was found fractured. The main damage occurred in the blade row 36 which is the L-3 row of the flow in the turbine side. The key objective of this paper was to identify the root of the failure.
A paper published in « Case Studies in Engineering Failure Analysis« , July 2013
A commercial gas velocity sensor used for flue gases monitoring was subject to severe corrosion failure. An investigation was conducted based on visual inspection, microstructural study and SEM observation coupled to EDX analysis. A combination of mechanisms was proposed including a dominating 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.
An article published in « Case Studies in Engineering Failure Analysis« , July 2013.
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. In the case of failed sample, the reason for the poor wear resistance of the component was due to the non-uniform carbide in pearlitic matrix.
A case study published in « Case Studies in Engineering Failure Analysis » on www.sciencedirect.com.
The wellhead flow control valve bodies which are the focal point of this failure case study were installed in some of the upstream facilities of Khangiran’s sour gas wells. These valve bodies have been operating satisfactorily for 3 years in wet H2S environment before some pits and cracks were detected in all of them during the periodical technical inspections. During investigation many cracks were observed on the inner surface of the valve body grown from the surface pits. The results indicate that flow control valve body failed due to combination of hydrogen induced corrosion cracking (HICC) and sulfide stress corrosion cracking (SSCC). According to HIC and SSC laboratory tests and also with regard to cost of engineering materials, it was evident that the best alternative for the valve body alloy is A217-WC9 cast Cr–Mo steel.
A paper published in « Case Studies in Engineering Failure Analysis« , available on sciencedirect.com.
Corrosion has always been a problem in the petroleum refining and the petrochemical operations. The equipment of ISOMAX unit, such as reactors, furnace tubes, valves, and pipelines are frequently performed at high temperatures and high pressure condition. This working conditions, accelerates the failures due to corrosion. Therefore, heat- and corrosion-resistant alloys, e.g., austenitic stainless steels, have been widely used in this unit because of their excellent corrosion resistance, mechanical strength and toughness.
This paper describes failure analysis procedure of a cracked high pressure 321 SS RTJ flange in ISOMAX unit. In order to get conclusions related to crack propagation mechanisms of the flange, some investigations were done on the cracked flange that is mentioned in the body of the paper.
A paper published in « Case Studies in Engineering Failure Analysis« , available on sciencedirect.com.
As a qualification of bolt for flight assembly, the bolt assembly has undergone proof pressure test at 2.4 MPa, Vibration test at frequency range of 20–100 Hz, ±3 db/oct for 120 s in both lateral and longitudinal directions and flight acceptance test. During routine visual inspection before electrical check, it was observed in one of the three fasteners that the head of the bolt had got sheared off from the shank portion of bolt. Further, a failure analysis was carried out on the failed bolt.
The objective of the study is metallurgical analysis of the failed bolt, fractography study to find out the root cause of the failure, and optimization of processing parameters for fastener manufacturing.
A paper published in « Case Studies in Engineering Failure Analysis« , available on sciencedirect.com.
Catastrophic failure of a 10 m high, 8 m diameter steel storage tank containing approximately 350 m3 of waste solvent led to a significant environmental incident in 2009. An investigation was carried out to establish the root cause and to learn lessons that might prevent a reoccurrence.
A paper published in « Case Studies in Engineering Failure Analysis« , available on sciencedirect.com.
High strength low alloy (HSLA) steel with a nominal composition of 0.15C–1.25Cr–1Mo–0.25V is being extensively used in space programme. Owing to its ease of fabrication and welding, a tank was fabricated out of this alloy. The tank is used to contain strontium per chlorate which on combustion develop secondary thrust, effectively used during attitude control of satellite launch vehicle. During one of the routine qualification tests, a tank had failed at an internal pressure of 109 bar, against a designed proof pressure of 120 bar.
Failure was initiated from long seam weld of a cylindrical shell and propagated into the parent material thereafter. Detailed metallurgical investigation has been carried out to understand the cause of failure. This paper brings out the detail of investigation carried out.
A paper publihed in « Materials Today: Proceedings », available online at www.sciencedirect.com
Die design is one of the most important steps in Powder Metallurgy process because the shape and attributes of the die will directly affect the final component. Die design has a number of steps and considerations to be made before fabrication. This project is an attempt to design and fabricate a die for cold compaction process used in the powder metallurgy process.
More at : http://www.pmme.co.in/papers/EMT-388.pdf
