•Failure mechanism of a plate type amine exchanger was investigated.•Intergranular stress assisted corrosion cracking was the prevalent mechanism of failure.•Corrosion and cracking was more sever under the gasket region of the amine exchanger.
•Deficient torque practices lead to plastic deformation of lug nuts and wheel ejection.•Gap formation in machine elements promotes fatigue of bolts.•Local decarburization promotes crack formation in high strength bolts.
•The three failure modes tested are all due to over load failure of the acetal nut.•The three mechanisms discussed are as follows: (1) Overtightening of the supply line acetal nut, (2) Supply line lateral pull and, (3) Embrittled supply line lateral pull.•Failure from overtightening the acetal nut is possible, if a tool is used.•Failure from a lateral pull occurred at higher torques when embrittled.
•Sample entropy, an indicator reflecting the complexity of vibrations, is studied through the real field data.•Two industrical cases are introduced to verify the effectiveness of sample entropy.•For the purpose of comparison, other statistical indicators are applied to demonstrate the advantages of the proposed method.
•The reasons for the failure of a buried L415 steel pipe perforated during construction were analyzed.•An ultrahigh growth rate of pitting corrosion, as high as 14mm per year, was confirmed as the main reason of the failure.•The synergistic effect of high partial pressure of oxygen and concentrated Cl− in dust introduced improperly were responsible for the failure.
•A detailed investigation on failure of stabilized stainless pipe was performed in this study.•Cracking initiated from the outer side of pipe and propagated in the heat affected zone (HAZ).•Thermal fatigue crack growth and formation of chromium rich phase during welding and service condition lead to pipe failure.
This article describes the findings of a detailed investigation into the failure of a final super heater tube in a 140 MW thermal power plant. Preliminary macroscopic examinations along with visual examination, dimensional measurement, chemical analysis, evaluation of mechanical properties, and oxide scale thickness measurement were carried out to deduce the probable cause of failure. In addition, optical microscopy was a necessary supplement to understand the cause of failure. It was concluded that the tube had failed due to stress rupture. The tube metal had been exposed to a temperature above the safe operating limit for a long duration. As a result the tube metal had lost its strength, suffered creep deformation and failed to support the working stress resulting in final rupture. The adherent scale, particularly on internal surface formed due to exposure at high temperature. It had acted as an insulating blanket in view of its much lower thermal conductivity than that of the tube metal. The progressive build-up of scale had greatly affected heat transfer and raised the tube metal temperature above A1 for a short duration before bursting of the tube. The overheating in this case may be due to poor circulation over the localized area.
•Failure investigation has been conducted on a carbon steel roller shaft of continuous pad steam machine used in textile industry.•Visual examination, chemical analysis, hardness and tensile strength measurements, fractography and numerical modeling is used for the failure analysis.•SEM images and stress analysis results conclude the evidence of fatigue failure of shaft.
•Failed Tracked vehicle balance arm analyzed using NDT and Fractography.•Failure initiated with multiple cracks from spline teeth near the internal diameter.•Fracture was of brittle nature and occurred due to Manufacturing Fault i.e. MnS inclusions.•Loading condition, failure mode and state of stress determined.
•A leakage at the elbow used in the geothermal production facility was found after 2 months in service.•The main cause of failure was investigated through conducting standard failure analysis methods.•Results indicated that the cause of failure was erosion-corrosion by the presence of wall thinning.
•The transient thermal fatigue life of a gas turbine casing is investigated.•Residual stress induced by insertion of pin is investigated.•The arrangement of additional holes is discussed.•The fatigue crack propagation life of a gas turbine casing is investigated.
•The failure of the boiler water-wall tube is investigated.•The fire-facing side of the tube was observed to have experienced significant wall thinning.•The iron-to-oxygen ratio of the fire-facing side is smaller than that of the back side.•The failure occurred due to oxidation.
•We used industrial case study to carry out a failure study on the different vibrating screen sub-systems in order to lessen frequent failure.•We perform a sensitivity analysis on the RVS machine using different loading to determine the stress regions using ANSYS®.•We examine the stress distributions on the RVS machine and then implement improvements using lessens from industry as well as experts judgements.
•Thick and thin scale formation over inside wall of tube promoted local overheating.•Prolong exposure of tube material under high stress and temperature caused creep and material softening leading to reduction in wall thickness.•Under high hoop stress at that elevated temperature, thinned wall material ultimately failed exhibiting ‘fish mouth opening’.
•A dissimilar weld failure analysis of a heat exchanger in an H2S application has been conducted.•Dissimilar weld is between a carbon steel and duplex stainless steel.•Hardness profiles and SEM-EDS analysis are included.•Failure was due to sulfide-assisted stress corrosion cracking.•High hardness levels and local dilution of chemistry in the weld facilitated the failure.
•The paper presents a case study of failure of a stabilized stainless steel charge heater tube in heavy crude oil.•The paper presents an interesting finding, namely the occurrence of chloride stress corrosion cracking catalyzed by the presence of sulphur-bearing species.•The precipitation of salts and coke from the heavy crude led to sensitization of the internal surface layer and sulphidation of the crack walls.
•It is most likely that the connecting rod failed on the end of exhaust stroke, due to the tensile force being at the highest at TDC.•The sulphide scale-build-up on the connecting rod led to create a brittle phase that prone to cracking.•Surface Cracks reached a critical size, propagating until the part rapidly fractured.•Observation of the fracture surface reveals fatigue fracture morphology, as observed in similarly connecting rods.
•Two locations of the blade damage were observed namely damage at the root of the blade and the other one was at the third of the blade height.•The failure of the third of the blade height is owing to the fly ash collide to the leading edge of the blades causing erosion and notch.•The failure at the root blade was caused by broken fragments of the others damaged blades entered in between casing (stator) and the blade (rotor).
•The microstructure of the damaged rotor fist-stage blade root is similar to that of new blade.•The damaged rotor blade has the acceptable initial microstructure.•SEM images confirm the abnormal conditions. Increasing the service temperature leads to precipitates dissolved in the matrix and re-deposited during shut down of the turbine. Furthermore, the fractography observation confirms local melting in the leading edge.•Changes of the first-stage airfoil blade microstructure and local melting of blade indicates that the blades were overheated for unknown period of time.
•A field failure and finite element analyses of overheated pipe due to scale was performed.•The tube shows rupture with the shape of fish-mouth accompanied by bulging.•The analysis performed using finite element mimics the actual field conditions.•It was discovered that scale hinders the smooth heat transfer process.•Metallurgical evaluation proves this verdict. Furthermore, the FEA also supports the conclusion.
