bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corrosion and Cracking of the Internal Surfaces of a Black Liquor Digester
Authors: Port Robert D. 
Published: May 2019

Abstract
Routine inspections of a carbon steel wood pulp digester revealed a sharply increasing number of cracks in the overlay metal on the internal surface of the digester after 1 and 2 years of service. The weld overlay was composed of type 309 stainless steel on the top fourth of the digester and of a proprietary high-nickel material on the bottom three-fourths. Examination revealed three distinct modes of deterioration. General corrosion was linked to the use of unspecified overlay metal. Cracking resulted during installation from the use of a material susceptible to hot cracking. Deep corrosion fissures then developed at hot crack sites as a result of crevice corrosion. Use of the appropriate overlay material was recommended.
Stress-corrosion Fracture in Silver Solid-State Bonds of Uranium
Authors: Beitscher Stanley , Johns W.L. 
Published: May 2019

Abstract
Silver solid-state bonded components containing uranium failed under zero or low applied load several years after manufacture. The final operation in their manufacture was a proof loading that applied a sustained tensile stress to the bond, which all components passed. The components comprised circular cylinders fabricated by plating a thin layer of silver on each of the contact surfaces (uranium and stainless steel) and pressing the parts together at elevated temperature to solid-state bond the two silver surfaces. The manufacturing process produced a high level of residual stress at the bond. The failures appeared to be predominantly located between the silver layer and the uranium substrate. Normal fracture location of specimens taken from similar components was at the silver/silver bond interface. Laboratory testing revealed that the uranium/silver joint was susceptible to premature failure by stress-corrosion cracking under sustained loading if the atmosphere was saturated with water vapor.
Failure Analysis of the Moderator Branch Pipe of a Pressurized Hot Water Reactor
Authors: Florio Antonio , Crespi Juan C. 
Published: May 2019

Abstract
Type 347 stainless steel moderator circuit branch piping in a pressurized hot water reactor was experiencing frequent leakage. Investigation of the problem involved failure analysis of leaking pipe specimens, analytical stress analysis, and determination of “leak-before-break” conditions using fracture mechanics and thermal fatigue simulation tests. Failure analysis indicated that cracking had been initiated by thermal fatigue. Data from the analysis were used in making the leak-before-break predictions. It was determined that the cracks could grow to two-thirds of the circumferential length of the pipe without catastrophic failure. A thin stainless steel sleeve was inserted in the branch pipe to resolve the problem.
Rapid Pitting Failure of Type 304 Stainless Steel Pipework
Authors: Stott Jim 
Published: May 2019

Abstract
Several hundred leaks were reported in the type 304 stainless steel pipelines, vessels, and tanks of a chemical plant at a tropical location within a few weeks after startup. Investigation of the failure involved a site visit, metallographic examination and analysis of the material, analysis of hydrotest waters, and microbiological examination of slime that had formed in certain pipework sections. It was determined that the failure resulted from microbially induced corrosion promoted by the use of poor-quality hydrotest water and uncontrolled hydrotesting practice. Use of appropriate hydrotesting procedures was recommended to prevent similar failures.
Single-Phase Erosion Corrosion of a 460 mm (18 in.) Diam Feedwater Line Break
Authors: Czajkowski Carl J. 
Published: May 2019

Abstract
A 460 mm (18 in.) diam suction line to the main feed water pump for a nuclear power plant failed in a violent, catastrophic manner. Samples of pipe, elbow, and weld materials (ASTM A106 grade B carbon steel, ASTM A234 grade WPB carbon steel, and E7018 carbon steel electrode, respectively) from the suction line were analyzed. Evidence of overall thinning of the elbow and pipe material and ductile tearing of fractures indicated that the feed water pipe failed as a result of an erosion corrosion mechanism, which thinned the wall sufficiently to cause rapid, ductile tearing of the material after its design stress had been exceeded. It was recommended that steel with a higher chromium content be used to mitigate the erosion corrosion potential in the lines and that more rigorous nondestructive (ultrasonic) examinations be performed.
Fatigue Failure of a Carburized Steel Gear From a Helicopter Transmission
Authors: Roth Martin , Sander Karen 
Published: May 2019

Abstract
The failure of a spiral bevel gear from the transmission of a helicopter was discovered when the transmission was removed after an in-flight incident. Two adjacent teeth from the carburized AISI 9310 steel gear were found to have undergone fatigue failure. Internal initiation occurred in a region depleted of chromium and nickel. This condition coincides with a microstructural inhomogeneity consisting of large, soft ferrite grains. Its origin was probably contamination of the solidifying ingot during the consumable vacuum arc remelting operation.
Flow-Induced Vibration Fatigue of Stainless Steel Impeller Blades in a Circulating Water Pump
Authors: Brown Samuel J. , Bravenec Edward V. 
Published: May 2019

Abstract
Several large-diameter type 304L stainless steel impeller/propeller blades in a circulating water pump failed after approximately 8 months of operation. The impeller was a single casting that had been modified with a fillet weld buildup at the blade root. Visual examination indicated that the fracture originated near the blade-to-hub attachment in the area of the weld buildup. Specimens from four failed castings and from an impeller that had developed cracks prior to design modification were subjected to a complete analysis. A number of finite-element-method computer models were also constructed. It was determined that the blades failed by fatigue that had been accelerated by stress-corrosion cracking. The mechanism of failure was flow-induced vibration, in which the vortex-shedding frequencies of the blades were attuned to the natural frequency of the blade/hub configuration. A number of solutions involving material selection and impeller redesign were recommended.
Fracture of a Turbine Impeller Shaft
Authors: D'Antonio Carmine 
Published: May 2019

Abstract
An ASTM A193-83a grade B7 (AISI 4140) steel turbine impeller shaft fractured after 2 months of service. Failure had initiated at three separate points around the periphery of the shaft, each associated with one of three keyways. SEM fractography, metallography, and chemical analysis indicated that the mechanism of fracture initiation was torsional fatigue. Intermittent deceleration and acceleration resulting from power surges during operation of the turbine caused torsional vibration and was considered the most probable source of the required cyclic stress. Final failure took place by torsional shear.
Fractures of Hot Dip Galvanized Steel Anchor Bolts in Chemical Plant Construction Project
Authors: Kerns George E. , Mighton Charles E. 
Published: May 2019

Abstract
Galvanized A36 steel unsleeved shear-type anchor bolts failed during installation. The galvanized steel bolts were approximately 18 mm (0.7 in.) in diameter with a 90 deg bend between the long and short legs. As-fractured, sawcut, and unfractured specimens were examined. Failure analysis revealed dark thumbnail regions at the fracture origins and a very narrow and uniform shear lip. The thumbnail region exhibited zinc deposits with no apparent fracture detail, indicating preexisting cracks that had occurred before galvanizing. The balance of the fracture exhibited a transgranular mode with cleavage and ductile, dimpled shear. Hardness values as high as 35 HRC were measured in the bend area. The as-galvanized bolts fractured in a brittle manner. Failure was attributed to improper bending of the bolts, which provided a severely cold-worked bend area susceptible to strain-age embrittlement.
Failure of a Tied Universal Expansion Joint
Authors: Bowman Ralph D. 
Published: May 2019

Abstract
A tie rod, nut, and bellows from a failed 610 mm (24 in.) diam tied universal expansion joint that carried tail gases consisting of N2 + O2 with slight traces of nitrogen oxides and water were examined. The materials were SA 193-B7 (AISI 4140), SA 194–214, and Incoloy 800H, respectively. Visual examination of the bellows revealed cracks in heavily cold-worked areas (both inside and outside) and considerable corrosion. SEM analysis showed a classical intergranular failure pattern with microcracking. The threaded tie rod microstructure contained spheroidized carbide that was more pronounced at the tie rod end of the failure. Energy-dispersive X-ray analysis of fracture surfaces from the bellows showed the presence of chlorine and sulfur. Failure of the bellows was attributed to stress-corrosion cracking, with chlorine and sulfur being the corroding agents. The rod damage was the result of failure of the bellows, which allowed escaping hot gases to impinge on the tie rods and heat them to approximately 595 deg C (1100 deg F). It was recommended that the insulation be analyzed to determine the origin of the chlorine and sulfur and that it be replaced if necessary.
Brittle Fracture of the Tension Flange of a Steel Box-Girder Bridge
Authors: Hartbower Carl E. 
Published: May 2019

Abstract
A catastrophic brittle fracture occurred in a welded steel (ASTM A517 grade H) trapezoidal cross-section box girder while the concrete deck of a large bridge was being poured. The failure occurred across the full width of a 57 mm (214 in.) thick, 760 mm (30 in.) wide flange and arrested 100 mm (4 in.) down the slant web. Failure analysis revealed a major deficiency in fracture toughness. The failure occurred as a brittle fracture after the formation of a welding hot crack and approximately 40 mm (112 in.) of slow crack growth. It was recommended that bridges fabricated from this grade of steel undergo frequent inspection and that stringent test requirements be imposed as a condition of use in non-redundant main load-carrying components.
Failure of an I-Beam
Authors: Dayal R.K. , Gnanamoorthy J.B. , Rodriguez P. 
Published: May 2019

Abstract
An I-beam of IS-226 specification—I-section dimensions of 450 x l50 x 10 mm (17.7 x 5.9 x 0.4 in.) and a length of 12.41 m (40.7ft)—was flame cut into two section in an open yard near these a coast under normal weather conditions. After approximately 112h, the shorter section of he I-beam split catastrophically along the entire length through the web. Detailed investigation revealed segregation of high levels of carbon, sulfur and phosphorus in the middle of the web and high residual stresses attributed to rolling during fabrication. Flame cutting caused a change in the distribution of the residual stresses, which, aided by low fracture toughness due to the poor quality of the beam, resulted in failure. It was recommended that segregation be avoided in cast ingots used for I-beam manufacture by implementing a better quality-control procedure.
Brittle Fracture of a Marine Riser Clamp
Authors: Mahmoud Salah E. 
Published: May 2019

Abstract
An API type 2 steel clamp located on the riser of a semisubmersible drilling rig between the lower ball joint and riser blowout preventer (BOP) conductor failed after 7 years of service. Failure analysis revealed the cause of failure to be the low toughness of the clamp material. Contributing factors included the presence of a hard, brittle, heat-affected zone and weld defects at the handling pad eye. It was recommended that the replacement clamp be made from a material with good toughness and that any installation of attachments by welding be done according to qualified procedures.
Failure of 9% Ni Steel Production Tubing
Authors: Billings Robert M. 
Published: May 2019

Abstract
During a work over of an oil well, the 9% Ni steel production tubing parted three times as it was being pulled from the well. The tubing had performed satisfactorily for more than 30 years in the well A representative failure, a circumferential fracture in a connection, was analyzed. Reported to be a hydril CS connection, the pin end parted near the last threads. The external surface exhibited mechanical damage marks from the fishing operation. No signs of external corrosion or damage were detected. Visual surface examination revealed shear lips at the outside pipe, indicating that the fracture initiated at the inside surface and grew across the wall. Longitudinal cross sections revealed heavy corrosion damage to the inside pipe surface. Metallographic examination indicated that the tubing failed as a result of severe weakening from internal corrosion. Gray-colored corrosion deposits, which penetrated the pipe throughout the grain boundaries of the material and concentrated in the matrix in a layer near the inside surface of the pipe, were observed. The presence of H2S in the produced fluids and the appearance of the gray deposit indicated that the tube suffered H2S corrosion. Chemical analysis of the base metal and corrosion deposits did not detect iron or nickel sulfides, however Replacement of the remaining pipe strings according to a scheduled program was recommended. Because 9% Ni steel was not available, 13% Cr martensitic stainless steel was recommended as a replacement.
Failure of Stainless Steel Springs Used in an Oil Ring Lip Seal
Authors: Neff Michael 
Published: May 2019

Abstract
Failure of AISI type 321 stainless steel internal springs from newly manufactured lip seals on a shaft between a turbine power unit and a pump in a commercial aircraft secondary unit was investigated. Examination of the coils from two failed springs showed that both had failed by fatigue. The springs contained drawing defects that served as the fatigue crack initiation sites. It was recommended that the wire drawing process be investigated for various levels of steel cleanliness to predict the incidence of drawing defects at the wire surface. Stress analysis to determine the minimum tolerable defect size was also recommended.
Sledgehammer Chipping Failure
Authors: Garber Richard 
Published: May 2019

Abstract
A sledge hammer chipped during use. The chip struck a by stander in the eye, leading to its loss. The hammerhead surface was examined visually, nondestructively (magnetic particle method), and stereo microscopically, and a microstructural analysis of a cross section of the head was conducted using optical microscope. Chemical composition of the hammerhead was determined by emission spectrometry. The chemical compositions of the chip and hammer head were compared using energy-dispersive analysis. Microhardness versus distance from the striking face was also determined. The hammerhead material was UNS G10800 (AISI/SAE grade 1080). Excessive hardnesses were measured in the first 3 mm (0. 12 in.) below the striking surface, indicating that there was lack of control during the final tempering operation.
Fatigue Fracture of Aluminum Wires in High-Voltage Electrical Cables in Alaska
Authors: Chakrapani Durgam G. 
Published: May 2019

Abstract
Several wires in aluminum conductor cables fractured within 5 to 8 years of, service in Alaskan tundra. The cables were comprised of 19-wire strands; the wires were aluminum alloy 6201-T81. Visual and metallographic examinations of the cold-upset pressure weld joints in the wires established that the fractures were caused by fatigue loading attributable to wind/thermal factors at the joints. The grain flow at the joints was transverse to the wire axis, rendering the notches of the joints sensitive to fatigue loading. An additional contributory factor was intergranular corrosion, which assisted fatigue crack initiation/propagation. The failure was attributed to the departure of conductor quality from the requirements of ASTM B 398 and B 399, which specify that “no joints shall be made during final drawing or in the finished wire” and that the joints should not be closer than 15 m (50 ft). The failed cable did not meet either criterion. It was recommended that the replacement cable be inspected for strict compliance to ASTM requirements.
Delayed Fracture of Tempered Glass Panels Due to Nickel Sulfide Inclusions
Authors: Huet Roland , Wolf Joel M. , Moncarz Piotr D. 
Published: May 2019

Abstract
The spontaneous breakage of tempered glass spandrel panels used to cover concrete wall panels on building facades was investigated. Between January 1988 and August 1990, 19 panel failures were recorded. The tinted panels were coated on their exterior surfaces with a reflective metal oxide and covered on the back surfaces with an adherent black polyethylene plastic. Macro fractography, SEM fractography, EDX analysis, and photo elasticimetry were conducted on four of the shattered panels. Small nickel sulfide inclusions were found at the failure origins. Failure of the panels was attributed to growth of the inclusions, coupled with high residual stresses. Fracture mechanics analysis showed that the residual stresses alone were high enough to cause fracture of the glass, with a flaw of the size observed.
Failure of a Cast Steel Crane Bolster
Authors: Stone Alan 
Published: May 2019

Abstract
The failure of a 45 Mg (50 ton) rail crane bolster was investigated. Spectrochemical analysis indicated that the material was a 0.25C-1.24Mn-0.62Cr-0.24Mo cast steel. SEM examination revealed the presence of fatigue, as well as intergranular and ductile fractures. Microstructural analysis focused on an area where an antisway device had been welded to the structure and revealed the presence of coarse, untempered martensite that had resulted from faulty weld repair techniques. It was suggested that the use of proper welding procedures, including preheating and postheating, would have prevented the failure.
Spalling of a Ball-Peen Hammer
Authors: D'Antonio Carmine 
Published: May 2019

Abstract
A carbon steel ball-peen hammer ejected a chip that struck the user's eye. Failure occurred when two hammers were struck together during an attempt to free a universal joint from an automotive drive shaft. Two samples were cut from the face of the hammer one through the chipped area on the chamfer and the other from the undamaged area on the chamfer. The shape and texture of the fracture surfaces were typical of spalling. The fracture was conchoidal and exhibited a complete lack of plastic deformation. White etching bands that intersected the face and chamfer were revealed during metallographic examination. Fracture occurred through a white band. Failure was attributed to formation of envelopes of untempered martensite under the chamfer that ruptured explosively during service.
Corrosion Failure of Stainless Steel Components During Surface Pretreatment
Authors: Dayal R.K. , Gnanamoorthy J.B. , Division Metallurgy , Srinivasan G. 
Published: May 2019

Abstract
Two AISI type 316 stainless steel components intended for use in a reducer section for sodium piping in a fast breeder test reactor were found to be severely corroded—the first soon after pickling, and the second after passivation treatments. Metallographic examination revealed that one of the components was in a highly sensitized condition and that the pickling and passivation had resulted in severe intergranular corrosion. The other component was fabricated from thick plate and, after machining, the outer surface represented the transverse section of the original plate. Pickling and passivation resulted in severe pitting because of end-grain effect. Strict control of heat treatment parameters to prevent sensitization and modification of pickling and passivating conditions for machined components were recommended.
Cracking During Forging of Extruded Aluminum Alloy Bar Stock Material
Authors: Das A.K. 
Published: May 2019

Abstract
During the preproduction stages of forging, an initial batch of 50 mm (2 in.) diam Al-4Cu alloy (L77) extruded bar stock material was found to be cracking randomly. Failure analysis was conducted to determine the metallurgical factors underlying the phenomenon. Microexamination of sections across the defects revealed intergranular cracks tracing a path of round, segregated particles and oxide film discontinuities. The segregated particles were rich in copper It was concluded that the cracking was the result of segregations occurring in poor-quality raw material. The source of segregation was suspected to be the use of improperly made master alloys. Use of improved melting techniques and proper master alloys was recommended.
Failure of Compound Bow Handle Risers
Authors: Goodrich George M. 
Published: May 2019

Abstract
Compound bow handle risers that had failed in service and during assembly along with an unassembled riser were submitted for analysis. The risers were die cast from magnesium-base alloy AM60A. Inspection of the failed risers and metallurgical investigations conducted on the stock riser revealed the presence of cold shuts at the same site in all specimens. It was recommended that all risers be thoroughly inspected and that the bow company work with their die casting shop to design a mold with acceptable filling characteristics.
Fatigue Fracture of a Helicopter Tail Rotor Blade Due to Field-Induced Corrosion
Authors: McSwain Richard H. 
Published: May 2019

Abstract
A helicopter tail rotor blade spar failed in fatigue, allowing the blade to separate during flight. The 2014-T652 aluminum alloy blade had a hollow spar shank filled with lead wool ballast and a thermoset polymeric seal. A corrosion pit was present at the origin of the fatigue zone and numerous trails of corrosion pits were located on the spar cavity's inner surfaces. The corrosion pitting resulted from the failure of the thermoset seal in the spar shank cavity. The seal failure allowed moisture to enter into the cavity. The moisture then served as an electrolyte for galvanic corrosion between the lead wool ballast and the aluminum spar inner surface. The pitting initiated fatigue cracking which led to the spar failure.
Processing-Induced Fatigue Fracture of a Helicopter Tail Rotor Blade
Authors: McSwain Richard H. 
Published: May 2019

Abstract
A helicopter tail rotor blade spar failed in fatigue, allowing the outer section of the blade to separate in flight. The 7075-T7351 aluminum alloy blade had fiberglass pockets. The blade spar was a hollow “D” shape, and corrosion pits were present on the inner surface of the hollow spar A single corrosion pit, 0.38 mm (0.015 in.) deep, led to a fatigue failure of the spar The failure initiated on the pylon side of the blade. Dimensional analysis of the spar near the failure revealed measurements within engineering drawing tolerances. Though corrosion pitting was present, there was an absence of significant amounts of corrosion product and all of the pits were filled with corrosion-preventative primer. This indicated that the pitting occurred during spar manufacture, prior to the application of the primer The pitting resulted from multiple nickel plating and defective plating removal by acid etching. Post-plating baking operations subsequently reduced the fatigue strength of the spar.
Fatigue Fracture of a Transport Aircraft Crankshaft During Flight
Authors: Das A.K. 
Published: May 2019

Abstract
A 4340 steel piston engine crankshaft in a transport aircraft failed catastrophically during flight. The fracture occurred in the pin radius zone. Fractographic studies established the mode of failure as fatigue under a complex combination of bending and torsional stresses. SEM examination revealed that the fracture origin was a subsurface defect-a hard refractory (Al2O3) inclusion—in the zone close to the pin radius. Chemical analysis showed the crankshaft material to be of inferior quality. It was recommended that magnetic particle inspection using the dc method be used to cheek for cracks during periodic maintenance overhauls.