Abstract:Steel base metal laps or welding electrode surfaces were coated using graphene suspensions with various concentrations, and then the steel plates were welded using the shielded metal arc welding process. Microstructural observations showed that the addition of graphene to the weldment significantly refines the microstructure and promotes the formation of fine acicular ferrite. The results of mechanical testing indicated that with lower concentrations of graphene in the weldment, both the strength and ductility… Show more
“…Kadar unsur paduan pada baja laterit termasuk rendah (kurang dari 10%) sehingga disebut baja paduan rendah. Baja laterit ini memiliki kadar C sebanyak 0,49% yang menandakan baja karbon medium [15]. Hasil analisis komposisi kimia pada Tabel 2 menunjukkan bahwa baja laterit paduan Ni-Cr-Mn memiliki komposisi kimia yang mengacu pada baja AISI 4340.…”
Section: Hasil Pengujian Optical Emission Spectroscopy (Oes)unclassified
Lateritic ore is one of the raw materials for the steel industry. Lateritic ore processed into laterite steel has more advantages than steel in the market. It has better tensile strength, hardness, corrosion resistance, and welding properties. Lateritic steel is made by performing a casting process. This research aims to investigate the effect of reduction percentage on mechanical properties and microstructure of the lateritic steel after the hot rolling process. The specimens were heated to austenitization temperature at 1000 0 C for 1 hour before the rolling process. The reduction percentage varies by 10%, 15%, and 20%. Hardness and impact test was conducted using a Rockwell Hardness and Charpy method. The microstructure was observed using an optical microscope. The results showed the optimum hardness of 58 HRC in a hot rolling sample with 20% reduction. The highest impact strength of 46 Joule and ductile fracture took place in this sample. The microstructure of this sample showed a bainitic phase causing lower hardness.
“…Kadar unsur paduan pada baja laterit termasuk rendah (kurang dari 10%) sehingga disebut baja paduan rendah. Baja laterit ini memiliki kadar C sebanyak 0,49% yang menandakan baja karbon medium [15]. Hasil analisis komposisi kimia pada Tabel 2 menunjukkan bahwa baja laterit paduan Ni-Cr-Mn memiliki komposisi kimia yang mengacu pada baja AISI 4340.…”
Section: Hasil Pengujian Optical Emission Spectroscopy (Oes)unclassified
Lateritic ore is one of the raw materials for the steel industry. Lateritic ore processed into laterite steel has more advantages than steel in the market. It has better tensile strength, hardness, corrosion resistance, and welding properties. Lateritic steel is made by performing a casting process. This research aims to investigate the effect of reduction percentage on mechanical properties and microstructure of the lateritic steel after the hot rolling process. The specimens were heated to austenitization temperature at 1000 0 C for 1 hour before the rolling process. The reduction percentage varies by 10%, 15%, and 20%. Hardness and impact test was conducted using a Rockwell Hardness and Charpy method. The microstructure was observed using an optical microscope. The results showed the optimum hardness of 58 HRC in a hot rolling sample with 20% reduction. The highest impact strength of 46 Joule and ductile fracture took place in this sample. The microstructure of this sample showed a bainitic phase causing lower hardness.
“…The progressive replacement of grain-boundary-nucleated Widmanstätten ferrite by acicular ferrite has also been reported by Fattahi et al [61], as a result of an increase in the TiO2 nanoparticle content. It is not, however, only the introduction of Ti-containing nano-particles that can achieve microstructural refinement and an improvement in tensile properties, since Jafarlou et al [62] brought about such changes by incorporating graphene nano-particles into welds deposited with cellulosic electrodes. Figure 12 The influence of increasing Mo and the addition of Ti on the temperature range for the gamma to alpha transformation in submerged arc weld metal [22].…”
Section: The Formation and Character Of Acicular Ferrite In Weld Metalsmentioning
Acicular ferrite is recognised as a desirable microstructural constituent in C-Mn and low-alloy steel weld metals. It is Widmanstätten ferrite that nucleates on the spheroidal non-metallic inclusions and grows by a reconstructive (diffusion-controlled) mechanism that proceeds substantially to completion. With increasing alloy content and/or cooling rate, the transformation to acicular ferrite may not be completed before the formation of bainite begins, the efficacy of inclusions in modern weld metal being such that colonies of bainite can nucleate on inclusions, forming by a displacive (shear) transformation mechanism, and producing colonies of similar size to acicular ferrite laths. Hence, in arc welds deposited with modern welding consumables, both acicular ferrite and intragranular bainite may form. As a consequence of the similarity in appearance of these two microstructural constituents in the optical microscope, some confusion in terminology has been introduced into the literature. This review seeks to eradicate this confusion.
“…On the other hand, economic incentives toward actively utilizing carbon-based products have been recently realized through the development of carbon nanomaterials (i.e., fullerene, carbon nanotubes (CNT), and graphene) and the accelerating market penetration in application fields ranging from water treatment , to next-generation structural steel, metal alloys coating, energy conversion and storage, − and electronics . Hydride-driven electrochemical CO 2 reduction to multicarbon gaseous and liquid products has been of interest for many years and the advancement of in situ characterization techniques has significantly contributed to providing experimental and theoretical insights on the process. , These insights during synthesis of gaseous and liquid multicarbon products have transcended to the nascent field of CO 2 reduction toward solid multicarbon products.…”
CO2 capture and conversion to value-added
products have
seen continued advancement in recent years through electrochemical
and thermochemical routes. In this work, we have adapted a facile
and potentially scalable thermochemical reduction technique that directly
reduces CO2 to different-quality reduced graphene oxide
(rGO) solids. Several characterization techniques have been undertaken
to investigate the role of two- and three-dimensional copper catalytic
substrates, reaction time, and CO2 humidity content on
the characteristics of the prepared rGO. Growth for 1 h at 550 °C
atop a uniform two-dimensional (2D) catalytic copper substrate under
a humidified CO2 environment (0.14 gH2O/gCO2) attained rGO with low defect densities (0.36 × 1011 cm–2) and high domain (31.9 nm) and crystallite
(3.32 nm) sizes. Detailed statistical Raman analyses over large areas
confirm that the mean defect distance of the synthesized rGO samples
is 16–20 nm, indicative of the intrinsic high quality attained.
The degree of reduction in rGO based on C/O ratios from 4 to 8 suggests
that operating conditions can be fine-tuned to attain different-quality
rGO with different attributable macroproperties such as conductivity
and hydrophilicity. The developed method of direct CO2 reduction
to rGO can be further tuned to produce different quality, morphology,
and yield of other high-value solid carbon-based materials for emerging
and existing applications.
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