Abdel-Monem El-Batahgy - Academia.edu (original) (raw)

Papers by Abdel-Monem El-Batahgy

Lasers in Manufacturing and Materials Processing

Hybrid laser-arc welding (HLAW) was applied for butt welding of 14.5 mm thick plates of ferritic ... more Hybrid laser-arc welding (HLAW) was applied for butt welding of 14.5 mm thick plates of ferritic cryogenic steel X8Ni9 containing 9% Ni, which is used for manufacturing storage and transport facilities of liquefied natural gas (LNG). The weld seam formation and the achievable metallurgical and mechanical properties of the hybrid welds were investigated experimentally for two types of filler wire, an austenitic wire dissimilar to the base metal (BM) and an experimentally produced matching ferritic wire. Safe penetration and uniform distribution of the austenitic filler metal in the narrow hybrid weld could only be achieved in the upper, arc-dominated part of the weld. The pronounced heterogeneous distribution of the austenitic filler metal in the middle part and in the root area of the weld could not ensure sufficient notched impact toughness of the weld metal (WM). As a result, a decrease in the impact energy down to 17 ± 3 J was observed, which is below the acceptance level of ≥ 34...

Materials Performance, Feb 1, 1997

After approximately 24 years of operation, a catastrophic failure took place at the inlet zone of... more After approximately 24 years of operation, a catastrophic failure took place at the inlet zone of a waste heat boiler at a chemicals plant. Creep damage was identified as the failure mechanism. The creep damage was accelerated by overheating due to the formation of a thick scale layer on the boiler tubes surface.

Key Engineering Materials, 2018

Attempt was made to improve the surface hardness and wear properties of AISI M2 high speed tool s... more Attempt was made to improve the surface hardness and wear properties of AISI M2 high speed tool steel. Laser surface melting (LSM) of tool steel was conducted with 2.2 KW Nd:YAG laser as heating source. Conventional hardening of the tool steel was applied. Characterizing the LSM, with optical and field emission scanning electron microscopy and surface hardness technique was used to evaluate the micro-hardness and mechanical behaviour of different regions of melting pool. AISI M2 tool steel is approximately HV 260, hardness after conventional treatment was 850 HV and the hardness after laser surface heat treatment is around 900 HV. It was found that there is a considerable influence of the laser power density and scanning velocity on the melted zone dimensions and the re-solidified structure. Increasing laser energy and reducing the laser scanning rate results in deeper and wider melt pool formation.

Procedia CIRP, 2020

BACKGROUND The study was conducted to examine the nationwide temporal trends of incidence, treatm... more BACKGROUND The study was conducted to examine the nationwide temporal trends of incidence, treatment, and short-term outcomes for acute myocardial infarction (AMI) over a 15-year period in Taiwan. METHODS We identified patients who were hospitalized for incident AMI between 1997 and 2011 from the inpatient medical claim data set of the National Health Insurance Research Database. Age-and sexadjusted incidence and in-hospital mortality rates were calculated for AMI, and separately for ST-segment elevation and non-ST-segment elevation myocardial infarction (STEMI and NSTEMI).

After only one year of operation, thermowells in feed gas supply pipeline at a natural gas produc... more After only one year of operation, thermowells in feed gas supply pipeline at a natural gas production plant was failed due to fatigue damage accelerated by improper thermowell design for the current operation. It is believed that thermowell configuration having a neck acted as local stress raiser played a remarkable role in initiation of fatigue damage. Besides, the medium flow past a thermowell causes vortices to be shed at a frequency, termed the wake frequency, proportional to the flow velocity. If the wake frequency is at or near the natural frequency of thermowell, a resonance condition may occur where massive amounts of energy are absorbed by the thermowell, resulting in very high stresses and possible failure.

Materials, Nov 30, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY, 1994

The varestraint cracking test was carried out to assess the hot cracking tendency of alloy 800 at... more The varestraint cracking test was carried out to assess the hot cracking tendency of alloy 800 at different welding conditions and augmented strain levels. The test results revealed that the hot cracking susceptibility of alloy 800 increases with increasing the heat input and augmented strain levels. This emphasizes the role of constraint either internally induced or externally applied to the welded structure. A cracking threshold or the minimum augmented strain (•¸min) below which no hot cracking takes place has been found to be 0.25 for alloy 800. Also, the Critical Strain Rate to Time (CSS) required to cause cracking was found to be 6.42•~10•¬-3 sec•¬-1 at welding condition of 100 Amp, 13 Volt and 140 mm/min.

ASM Failure Analysis Case Histories: Power Generating Equipment, 2019

Several waterwall tubes in a power station boiler failed after ten years of service. The boiler i... more Several waterwall tubes in a power station boiler failed after ten years of service. The boiler is a suspension type equipped with 30 IK boxes where retractable soot blowers are inserted to clean the inside of the boiler using high-pressure steam. The tubes, which operate at 693 deg F (367 deg C) and 2935 psi (20.5 MPa), failed near the IK boxes as a result of thermal fatigue. Thermal fatigue damage was accelerated by repetitive exposure to water droplets from the soot blower and the associated rapid cooling.

International Conference on Aerospace Sciences and Aviation Technology, 2009

The subject boiler is a vertical type with a capacity of 2063 ton/hr steam. Its operating and des... more The subject boiler is a vertical type with a capacity of 2063 ton/hr steam. Its operating and design pressure are 2608psi (18MPa) and 2928psi (20.2MPa) respectively while maximum outlet operating temperature is 1008 o F (542.2 o C). Water wall tubes are seamless tubes made of SA 210 and SA 213 T2 steels with nominal outer diameter of 2.5-3.0" (63.5-76.2mm) and wall thickness of 0.25-0.313" (6.35-7.95mm). After 77360 operating hours, some water wall tubes have experienced leakage. Leaked tubes were subjected to different non-destructive and destructive examinations to clarify cause of failure. Visual investigation showed through-thickness hole in base metal, close to weld region of two leaked tubes. Optical and scanning electron microscopic examinations of leaked zones disclosed complete decomposition of pearlite into ferrite and spheroidal carbides, creep voids, and grain boundary micro-cracking. It is concluded that failure of the subject boiler tubes is attributed mainly to long term localized overheating. This could be related to heat tinted area (oxidation) formed on tube outer surface by heating (arc strike) during welding. During operation, oxidized or scale layer formed on outer surface of heat-tinted area will be exfoliated due to thermal stresses. Repeated cycles of thermal oxidation and exfoliation of scale layer will result in localized thinning and subsequently, localized overheating leading to acceleration of microstructure degradation. Thinning of water wall-tubes together with its microstructure degradation will result in increase in boiler pressure above the maximum safe working pressure leading to complete failure or leakage of tubes. It was recommended that boiler water wall tubes to be checked using different nondestructive methods during the nearest shut down and all thinned zones of tubes to be replaced. In order to decrease the possibility of such failure in future, proper welding procedure should be applied so that heat-tinted areas due to heating or arc strike on tube outer surface to be avoided.

The present research work aims at clarification of the effect of the welding electrode type on th... more The present research work aims at clarification of the effect of the welding electrode type on the mechanical properties of SMA welded joints of 9%Ni steel plates. Properties of produced SMA welded joints were evaluated using different non-destructive and destructive investigation methods. In comparison with the conventionally used Ni-based welding electrode ENiCrMo-3 (AWS A5.11), an experimentally produced non-conventional ferritic welding electrode with 11%Ni (ENi11-Company specification) has resulted in a better combination of the mechanical properties of SMA welded joints of this steel type for critical cryogenic applications. Besides, a positive economic impact for the experimentally produced non-conventional ferritic welding electrode, due to its lower cost, could be another attractive aspect.

Materials Characterization, 2005

This paper investigates a failure in HP-Mod radiant tubes in a petrochemical plant. Tubes fail af... more This paper investigates a failure in HP-Mod radiant tubes in a petrochemical plant. Tubes fail after 90,000 h of working at 950 • C. Observed failure is in the form of excessive bulging and longitudinal cracking in reformer tubes. Cracks are also largely branched. The microstructure of service-exposed tubes was evaluated using optical and scanning electron microscopes (SEM). Energy-dispersive X-ray spectroscopy (EDS) was used to analyze and characterize different phases in the microstructure. The results of this study showed that carbides are coarsened at both the inner and the outer surface due to the long exposure to a carburizing environment. Metallography examinations also revealed that there are many creep voids that are nucleated on carbide phases and scattered in between dendrites. Cracks appeared to form as a result of creep void coalescence. Failure is therefore attributed to creep due to a long exposure to a high temperature.

Advances in Materials Science and Engineering, 2009

The present investigation was mainly concerned with characteristics of autogeneous laser butt wel... more The present investigation was mainly concerned with characteristics of autogeneous laser butt welding of 2 mm thickness nonheat treatableAA5052-H12,AA5083-H12 and 2 mm, 3 mm thickness heat treatableAA6061-T6aluminum alloys. The effect of laser welding parameters, surface cleaning, filler wire addition, and backing strip on quality of laser welded joints was clarified using 5 kW laser machine. It was found that all the investigated alloys showed tendencies for porosity and solidification cracking, particularly, at high welding speed (4 m/min). Porosity was prevented by accurate cleaning of the base metal prior to welding and optimizing the flow rate of argon shielding gas. Solidification cracking was avoided through two different approaches. The first one is based on the addition of filler metal as reported in other research works. The other new approach is concerned with autogeneous welding using a backing strip from the same base metal, and this could be applicable in production. P...

International Journal of Modern Communication Technologies and Research, 2018

SSRN Electronic Journal, 2022

Materials, 2021

The results disclosed that both the microstructure and mechanical properties of AA7075-T6 laser w... more The results disclosed that both the microstructure and mechanical properties of AA7075-T6 laser welds are considerably influenced by the heat input. In comparison with high heat input (arc welding), a smaller weld fusion zone with a finer dendrite arm spacing, limited loss of alloying elements, less intergranular segregation, and reduced residual tensile stress was obtained using low heat input. This resulted in a lower tendency of porosity and hot cracking, which improved the welded metal’s soundness. Subsequently, higher hardness as well as higher tensile strength for the welded joint was obtained with lower heat input. A welded joint with better mechanical properties and less mechanical discrepancy is important for better productivity. The implemented high-power fiber laser has enabled the production of a low heat input welded joint using a high welding speed, which is of considerable importance for minimizing not only the fusion zone size but also the deterioration of its proper...

Science and Technology of Welding and Joining, 2020

Motivated by the tensile strength loss of 9%Ni steel arc welded joints made using Ni-based austen... more Motivated by the tensile strength loss of 9%Ni steel arc welded joints made using Ni-based austenitic filler metals, the feasibility of maintaining the tensile strength using matching ferritic filler metal has been demonstrated. In comparison with shielded metal arc welded joint made using Ni-based austenitic electrode ENiCrMo-6, higher tensile strength comparable to that of the base metal was obtained using matching ferritic electrode. Besides, sufficient impact toughness energies with much lower mismatch were obtained for weld metal and heat-affected zone. Welded joint with a lower mechanical mismatching is of considerable importance for achieving acceptable combination of tensile strength and impact toughness. A better combination of these mechanical properties is ensured by applying a post weld heat treatment.

The present research work encloses results of experimental investigations of the interaction betw... more The present research work encloses results of experimental investigations of the interaction between welding process parameters for laser-beam and hybrid-laser-arc as well as type of the filler metal and the achievable mechanical properties of the weld joints on steel grade X8Ni9+QT640 for cryogenic service containing 9% nickel. The results obtained contribute to the development and conversion in the industrial practice a new laser beam-based welding technology for the automated manufacturing of facilities for the liquefaction, storage and the transport of natural gases (LNG facilities). The results show, that the martensitic microstructure of the laser weld metal including low amount of retained austenite not exceeding 3.5% leads to the relatively low V-notch impact energy. The remarkable heterogeneity in the chemical composition of the weld metal through the weld thickness could be recognized in the case of hybrid-laser-arc welding with ERNiCrMo-3 austenitic filler metal, what als...

Materials Performance, 2008

After only seven months of operation, a column reboiler in a mono-ethylene glycol recycling unit ... more After only seven months of operation, a column reboiler in a mono-ethylene glycol recycling unit at a natural gas production plant failed because of localized corrosion on the portion of the tubes in the tube sheet. This attack was caused by abnormal clearance between the tubes and tube sheet, due to poor manufacturing quality, which allowed deposits to collect and initiate crevice corrosion.