bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen Embrittlement of P-110 Couplings for Mating 180 mm (7 in.) Casing in Oilfield Production
Authors: Peterson Clifford W. , Day James 
Published: May 2019

Abstract
Several tin plated, low-alloy steel couplings designed to connect sections of 180 mm (7 in.) diam casing for application in a gas well fractured under normal operating conditions. The couplings were purchased to American Petroleum Institute (API) specifications for P-110 material. Chemical analysis and mechanical testing of the failed couplings showed that they had been manufactured to the API specification for Q-125, more stringent specification than P-110, and met all requirements of the application. Fractographic examination showed that the point of initiation was an embrittled region approximately 25 mm (1 in.) from the end of the coupling. The source of the embrittlement was determined to be hydrogen charging during tin plating. Changes in the plating process were recommended.
Failure of an ASTM A681-89 H13 Die Segment for Die Casting of Aluminum
Authors: Goodrich George , Divinsky Ilya 
Published: May 2019

Abstract
A segment from a premium-quality H13 tool steel die for die casting of aluminum failed after only 700 shots. The segment was subjected to visual, macroscopic, hardness, and metallographic testing. The investigation revealed that failure occurred as a result of fatigue at an electrical-discharge-machined surface where the resulting rehardened layer had not been removed. This rehardened layer had cracked, providing a source for fatigue initiation.
Intergranular Corrosion Failure in Zn-Al Alloy Solenoid Valve Seats
Authors: Jayakumar T. , Bhattacharya D.K. , Raj Baldev , Rodriguez P. 
Published: May 2019

Abstract
Extensive cracking was found in a batch of die-cast ZAMAK 3 solenoid valve seats during commissioning of the system in which they were installed. Scanning electron microscopic and chemical analyses conducted on one of the failed valve seats showed that the composition of the alloy was different from that specified. The presence of excess aluminum and lead impurities that had segregated to the grain boundaries, coupled with an inadequate amount of magnesium, resulted in intergranular corrosion and subsequent intergranular failure. Corrosion was accelerated by storage in a humid environment in a coastal area. It was recommended that proper chemical analysis of the zinc-aluminum alloy be carried out as a quality control procedure.
Failure of an Aluminum Connector in an Electrical Transmission Cable
Authors: Furtado H.C. , Mannheimer W.A. 
Published: May 2019

Abstract
An 1100 aluminum alloy connector of a high-tension aluminum conductor steel-reinforced (ACSR) transmission cable failed after more than 20 years in service, in a region of consider able industrial pollution. The steel core was spliced with a galvanized 1020 carbon steel sheath. Visual examination showed that the connector had undergone considerable plastic deformation and necking before fracture. The steel sheath was severely corroded, and the steel splice was pressed off-center in the axial direction inside the connector. Examination of the fracture surface and micro-structural analysis indicated that the failure was caused by mechanical overload, which occurred because of weakening of the steel support cable by corrosion inside the fitting. The corrosion was ascribed to defective assembly of the connector which allowed moisture penetration.
Failure of Hot-Rolled Steel Bars
Authors: Stone Alan 
Published: May 2019

Abstract
Two 25 x 40 mm (1 x 1.5 in.) AISI 4150 hot-rolled steel bars that cracked during heat treatment were examined to determine whether the heat treating procedure had contributed to the failure. Metallographic examination of a cross section taken through the fracture revealed an oxide coating on both sides of the fracture surface. The oxide was also found on the top and bottom sides of the sample. Sawcut sides of the bar did not exhibit the oxide layer The presence of the oxide in the fracture, combined with its absence on all exterior surfaces, indicated that the fracture occurred as a result of an oxide seam in the original material rather than from oxide from heat treating. Nondestructive testing prior to machining and heat treatment was recommended.
Failure of the Bond Between a Cobalt Alloy Prosthetic Casting and a Sintered Porous Coating
Authors: Lisin Mark , Peterson Robert R. 
Published: May 2019

Abstract
A femoral knee implant was returned to the casting vendor for analysis after exhibiting poor bond strength between the cast substrate and a sintered porous coating. Both the coating and the substrate were manufactured from a cobalt-chromium-molybdenum alloy. Metallographic analysis indicated that a decarburized layer existed on all surfaces of the casting, which prevented bonding during the sintering thermal cycle. Bead-to-bead bonding within the coating appeared sufficient, and no decarburized layer was present on the bead surfaces. It was concluded that the decarburization did not occur during the sintering thermal cycle. It was recommended that the prosthetic manufacturer investigate atmosphere controls for all thermal cycles prior to coating.
Tensile Failure of a Hoist Chain Link
Authors: Casler Arvid A. 
Published: May 2019

Abstract
An ASTM A391 steel chain link of an over head hoist failed catastrophically, causing damage to both property and personnel. Macrofractography identified the sequence of fractures within the chain link. The first fracture occurred at the welded joint, a second occurred opposite the weld. SEM fractography and metallography indicated that the link failed in a ductile manner because of tensile overload, which occurred when the hoist hook contacted the hoist's housing and prevented uptake of the chain. It was recommended that a load-sensing device be installed to prevent future occurrences and that a dye penetrant inspection be performed on the renwinder of the chain.
Chloride-Induced Stress-Corrosion Cracking of Cooling Tower Hanger Rods
Authors: Weiss Wendy L. 
Published: May 2019

Abstract
One-quarter inch diameter 304 stainless steel cooling tower hanger rods failed by chloride-induced stress-corrosion cracking (SCC). The rods were located in an area of the cooling tower where the air contains drop lets of water below the mist eliminators and above the flow of water The most extensive cracking was observed in the rod nuts and in the portions of the rod which were covered by the nuts. Cracking was transgranular with extensive branching, and some corrosion occurred along the crack paths. The clamping force from the nuts used on both sides of the supported member and residual stresses from thread rolling likely contributed to the stresses for the cracking mechanism, along with the stresses induced by the supported load. The external surfaces of the hanger rods were reportedly exposed to a chloride-containing atmosphere, likely due to the biocide. Type 304 stainless steel is not a suitable material for this application, and materials that resist SCC, such as Inconel, should be considered.
Failure of a Laminated-Paper Food Cooking Tray
Authors: Leeser David O. 
Published: May 2019

Abstract
A laminated-paper microwave food tray collapsed with hot food in it. Microscopic examination of the failed tray revealed no structural or material defects. Five additional trays of like construction were also tested to determine the conditions necessary to simulate the permanent deflection of the tray handles that had occurred in the failed tray. Full distortion of the handles was obtained experimentally only by dropping a full hot tray on its end onto the floor. The test results indicated that the tray had slipped from the hand of the user.
Hydrogen Damage of Waterwall Tubes
Authors: Hahn Sarah Jane , Wiser Jimmy D. 
Published: May 2019

Abstract
Waterwall tube failure samples removed from a coal- and oil-fired boiler in service for 12 years exhibited localized underdeposit corrosion and hydrogen damage. EDS and XRD revealed that bulk internal deposits collected from the tubes contained metallic copper which can accelerate corrosion through galvanic effects and can promote hydrogen damage. Ultrasonic testing was recommended to locate tubes with severe gouging and corrosion, which are suspect locations for hydrogen damage. The source of the copper should be identified and future chemical cleaning of the boiler should address its presence in the waterwall tubes.
Failure of a Steel Wire Rope From a Television Tower
Authors: D'Antonio Carmine 
Published: May 2019

Abstract
A 6 x 19 fiber core steel wire rope failed as it was being used to lower a steel television tower. Fracture of the rope occurred at a point under one of two clips used to fashion a spliced loop that was directly connected to the top of the tower. Microscopic examination of the fracture surfaces and the condition of the individual wires revealed that 59% of the wires failed by shear, 39% failed in tension, and 2% had been cut. In addition, 87% of the wires showed some degree of crushing damage, ranging from mild to severe. The failure was attributed to improper installation of the clips.
Failure of a Transmission Brake Disc
Authors: Lochanski Edward C. 
Published: May 2019

Abstract
Failure of AISI 1015 steel brake discs used in power transmissions in emergency winches was investigated using various testing methods. The failed discs were stampings that had replaced cast discs. Residual stresses in the fillets of new cast and new stamped brake discs were measured by x-ray diffraction. The results indicated that the stamped brake discs had failed by fatigue caused by a tensile residual stress pattern in the fillet. The residual stress pattern was attributed to the change in manufacturing process from casting to stamping. Use of a manufacturing process that yields a compressive residual stress in the fillet, appropriate heat treatment of stamped discs, or redesign of the disc and/or transmission assembly was recommended.
Hydrogen Embrittlement Cracking in a Batch of Steel Forgings
Authors: Das A.K. 
Published: May 2019

Abstract
The repeated occurrence of random cracks in the fillet radius portion of low-alloy steel (38KhA) end frame forgings following heat treatment was investigated. Microstructural analyses were carried out on both the failed part and disks of the rolled bar from which the part was made. Subsurface cracks were found to be zigzag and discontinuous as well as intergranular in nature. A mixed mode of fracture involving ductile and brittle flat facets was observed. Micropores and rod-shaped manganese sulfide inclusions were also noted. The material had a hydrogen content of 22 ppm, and cracking was attributed to hydrogen embrittlement. Measurement of hydrogen content in the raw material prior to fabrication was recommended. Careful control of acid pickling procedures for descaling of the hot-rolled bars was also deemed necessary.
Mechanical Failure of a Repair Welded Ferritic Malleable Cast Iron Spring Hanger
Authors: Johnson Alan A. , von Fraunhofer Joseph A. 
Published: May 2019

Abstract
The right front spring hanger on a dual rear axle of the tractor of a tractor-trailer combination failed, causing the vehicle to roll-over. The hanger was made from malleable cast iron that had been heat treated to produce a decarburized surface layer and a pearlitic transition layer. It had been repair welded after breaking into two pieces longitudinally in a prior incident, using cast iron as weld metal. The repair weld bead on both surfaces missed the fracture over 15 to 20% of their lengths. The incomplete repair weld and brittleness of the weld metal and heat-affected zones led to the failure.
Dealloying in Aluminum Bronze Components
Authors: Czajkowski Carl J. 
Published: May 2019

Abstract
Various aluminum bronze valves and fittings on the essential cooling water system at a nuclear plant were found to be leaking. The leakage was limited to small-bore socket-welded components. Four specimens were examined: three castings (an ASME SB-148 CA 952 elbow from a small-bore fitting and two ASME SB-148 CA 954 valve bodies) and an entire valve assembly. The leaks were found to be in the socket-weld crevice area and had resulted from dealloying. It was recommended that the weld joint geometry be modified.
Thermal Fatigue Failure of Alloy UNS NO8800 Steam Superheating Tubes
Authors: Islam Moavinul 
Published: May 2019

Abstract
Alloy UNS N08800 (Alloy 800) tubes of the steam superheating coils of two hydrocracker charge heaters in a refinery failed prematurely in service. Failure analysis of the tubes indicated that the failures could be attributed to thermal fatigue as a result of temperature fluctuations as well as restriction to movement. Fatigue cracks initiated intergranularly from both the flue gas and steam sides. Enhanced general and grain boundary oxidation coupled with age hardening of the alloy led to the formation of incipient intergranular cracks that acted as sites for the initiation of the fatigue cracks.
Failure of a Stainless Steel Tank Used for Storage of Heavy Water/Helium
Authors: Dayal R.K. , Chandrasekharan N. 
Published: May 2019

Abstract
The dished ends of a heavy water/helium storage tank manufactured from 8 mm (0.3 in.) thick type 304 stainless plate leaked during hydrotesting. Repeated attempts at repair welding did not alleviate the problem. Examination of samples from one dished end revealed that the cracking was confined to the heat affected zone (HAZ) surrounding circumferential welds and, to a lesser extent, radial welds that were part of the original construction. Most of the cracks initiated and propagated from the inside surface of the dished ends. Microstructures of the base metal, HAZ, and weld metal indicated severe sensitization in the HAZ due to high heat input during welding. An intergranular corrosion test confirmed the observations. The severe sensitization was coupled with residual stresses and exposure of the assembly to a coastal atmosphere during storage prior to installation. This combination of factors resulted in failure by stress-corrosion cracking. Implementation of a new repair procedure was recommended. Repairs were successfully made using the new procedure, and all cracks in the weld repair zones were eliminated.
Failure of AISI Type 347 Stainless Steel Bellows
Authors: Muralidharan N.G. , Kaul Rakesh , Kasiviswanathan K.V. , Raj Baldev 
Published: May 2019

Abstract
A number of AISI 347 stainless steel bellows intended for use in the control rod drive mechanism of a fast breeder reactor were found to be leaking before being placed in service. The bellows, which had been in storage for one year in a seacoast environment, exhibited a leak rate on the order of 1 x 10−7 cu cm/s (6 x 10−8 cu in./s). Optical metallography revealed numerous pits and cracks on the surfaces of the bellow convolutes, which had been welded to one another using an autogenous gas tungsten arc welding process. Microhardness measurements indicated that the bellows had not been adequately stress relieved. It was recommended that a complete stress-relieving treatment be applied to the formed bellows. Improvement of storage conditions to avoid direct and prolonged contact of the bellows with the humid, chloride-containing environment was also recommended.
Failure Analysis of Turbine Blades
Authors: Iorio Antonio F. , Crespi Juan C. 
Published: May 2019

Abstract
Two 20 MW turbines suffered damage to second-stage blades prematurely. The alloy was determined to be a precipitation-hardening nickel-base superalloy comparable to Udimet 500, Udimet 710, or Rene 77. Typical protective coatings were not found. Test results further showed that the fuel used was not adequate to guarantee the operating life of the blades due to excess sulfur trioxide, carbon, and sodium in the combustion gases, which caused pitting. A molten salt environmental cracking mechanism was also a factor and was enhanced by the working stresses and by the presence of silicon, vanadium, lead, and zinc. A change of fuel was recommended.
Fatigue Failure of an Aluminum Turbine Impeller
Authors: Tipton Anthony A. 
Published: May 2019

Abstract
An AMS 4126 (7075-T6) aluminum alloy impeller from a radial inflow turbine fractured during commissioning. Initial examination showed that two adjacent vanes had fractured through airfoils in the vicinity of the vane leading edges, and one vane fractured through an airfoil near the hub in the vicinity of the vane trailing edge. Some remaining vanes exhibited radial and transverse cracks in similar locations. Binocular and scanning electron microscope examinations showed that the cracks had been caused by high-cycle fatigue and had progressed from multiple origins on the vane surface. Structural analysis indicated that the fatigue loading probably had been caused by forced excitation, resulting in the impeller vibrating at its resonant frequency. It was recommended that the impeller design, control systems, and material of construction be changed.
Fracture of a Trunnion Bolt Used To Couple Railway Cars
Authors: D'Antonio Carmine 
Published: May 2019

Abstract
A trunnion bolt that was part of a coupling in a metropolitan railway system failed in service, causing cars to separate. The bolt had been in service for more than ten years prior to failure. Visual examination showed that the failure resulted from complete fracture at the grease port and surface groove located at midspan. Drillings machined from the bolt underwent chemical analysis, which confirmed that the material was AISI 1045 carbon steel, in accordance with specifications. Two sections cut from the bolt were subjected to metallographic examination and hardness testing. The fracture origin was typical of fatigue. The ultimate tensile strength of the bolt was in excess of requirements. Wear patterns indicated that the bolt had been frozen in position for a protracted period and subjected to repeated bending stresses, which resulted in fatigue cracking and final complete fracture. It was recommended that proper lubrication procedures be maintained to allow free rotation of the bolts while in service.
Hydrogen Damage in a Waterwall Boiler Tube Section
Authors: Weiss Wendy L. 
Published: May 2019

Abstract
The rear wall tube section of a boiler that had been in service for approximately 38 years was removed and examined. Visual examination of the tube revealed a small bulge with a through-wall crack. Metallography showed that the microstructure of the bulged area consisted of a few partially decarburized pearlite colonies in a ferrite matrix. The microstructure remote from the bulged area consisted of pearlite in a ferrite matrix. EDS analysis of internal deposits on the tube detected a major amount of iron, plus trace amounts of other elements. The evidence indicated that the bulge and crack in the tube resulted from hydrogen damage. Examination of the remaining water circuit boiler tubing using nondestructive techniques and elimination of any heavy deposit buildup was recommended.
PENINGKATAN RANAH KOGNITIF DAN AFEKTIF PESERTA DIDIK KELAS VI SDN 1 PENGENJEK PADA MATA PELAJARAN MATEMATIKA MELALUI PENDEKATAN CTL DENGAN MODEL PICTURE AND STUDEN ACTIVE
Authors: Sapii Sapii 
Published: May 2019

Abstrak: Penelitian ini bertujuan mencari gambaran yang sekaligus menjawab permasalahan penelitian dengan paparan deskripsi tentang penerapan Pendekatan CTL Dengan Model PASA (Picture and studen Active) dapat meningkatkan Ranah Kofnitif Dan Afektif Peserta Didik Kelas VI SDN 1 Pengenjek Pada Mata Pelajaran Matematika. Penelitian ini menggunakan pendekatan penelitin tindaka kelas (PTK) dengan subjek siswa kelas VI sebanyak 25 orang siswa. Berdasarkan hasil penelitian Pendekatan CTL mampu meningkatkan hasil belajar siswa pada mata pelajaran Matematika. Pada tahap prasiklus yaitu dari 25 siswa diperoleh data bahwa terdapat 17 atau 68% anak yang memperoleh nilai kurang dari KKM 75 dan 8 atau 32% anak yang nilainya lebih dari KKM dengan nilai rata-rata sebesar 67.6 Selanjutnya siklus I dari 25 siswa diperoleh data bahwa terdapat 12 atau 48% anak yang memperoleh nilai kurang dari KKM 75 dan 13 atau 52% anak yang nilainya lebih dari KKM 75 dengan nilai rata-rata sebesar 76.8, dan pada siklus II 25 siswa diperoleh data bahwa terdapat 5 siswa atau 20% yang memperoleh nilai kurang dari KKM 75 dan 20 atau 80% anak yang nilainya lebih dari KKM 75 dengan nilai rata-rata sebesar 83.2.. Abstract: This study aims to find a picture that simultaneously answers research problems with a description of the description of the application of the CTL Approach With Pasa Model (Picture and studen Active) can improve the Positive and Affective Domain of Class VI Students in SDN 1 Applicants in Mathematics. This study used a classroom action research (CAR) approach with 25 grade students as many as 25 students. Based on the results of the research CTL approach is able to improve student learning outcomes on Mathematics subjects. In the pre-cycle stage, 25 students obtained data that there were 17 or 68% of children who obtained less scores from KKM 75 and 8 or 32% of children whose grades were more than KKM with an average value of 67.6 Then cycle I of 25 students obtained data that there are 12 or 48% of children who get less grades from KKM 75 and 13 or 52% of children whose grades are more than KKM 75 with an average value of 76.8, and in cycle II 25 students get data that there are 5 students or 20% who get less value than KKM 75 and 20 or 80% of children whose grades are more than 75 KKM with an average value of 83.2.