Microstructure and Residual Stress Analysis of Explosion Cladded Inconel 625 and ASME SA516-70 Carbon Steel Bimetal Plates

Afonso

J Braz. Soc. Mech. Sci. Eng.

et al. 2018

Friction surfacing is a solid-state joining process that can be applied to develop similar or dissimilar combinations/joining partners that exhibit sound mechanical properties while avoiding some of the problems associated with the conventional deposition methods in which fusion is involved. Currently, however, the friction surfacing process is carried out in specialized equipment which do not yet have widespread industrial use. With the objective of exploring new application possibilities, in the present work, the viability of employing the friction surfacing process in a machining center with computerized numerical control was investigated. To this end, the deposition of 6351 Al-alloy coatings on a 1020 carbon steel substrate was pursued. After preliminary tests for determining viable deposition parameters, the influence of process variables (rod diameter, rotation, and forward speed) on coating geometry and mechanical properties was investigated using design of experiments methodology. Adhesion of the coatings was evaluated by applying a simple push-off test. The surface finish of the substrate plate was found to influence heat generation during the deposition process and impacted coating deposition. The results demonstrated that, although parameters must be carefully tuned, the process can be feasibly applied under the experimental conditions investigated, and a maximum push-off force value of 4250 N could be achieved.

Section: Microstructural Featuressupporting

confidence: 87%

Application of the friction surfacing process in a CNC machining center: a viability assessment for producing Al-alloy coatings on low carbon steel

Afonso

J Braz. Soc. Mech. Sci. Eng.

et al. 2018

“…When cooling, welded metals tend to expand to their initial sizes, which can produce high tensile stresses. For dissimilar metals, residual stresses can be even higher due to the difference in elastic, mechanical properties, and in thermal expansion coefficients [42]. After heat treatment, the average tear strength was also 94 MPa, but the strength distribution was more uniform along the length of the specimen.…”

Section: Metals 2020 10 X For Peer Review 7 Of 13mentioning

confidence: 99%

AlMg6 to Titanium and AlMg6 to Stainless Steel Weld Interface Properties after Explosive Welding

Malakhov

Saikov

Денисов

et al. 2020

Metals

This paper studies the weld interface microstructure and mechanical properties of AlMg6-stainless steel and AlMg6-titanium bimetals produced using explosive welding. The microhardness (HV), tear strength, and microstructure of the weld seams were evaluated. The interface of the weld zones had a flat profile. No structural disturbances or heterogeneity in the AlMg6-titanium weld interface were observed. On the other hand, the bimetal AlMg6-stainless steel had extensive zones of cast inclusions in the 10–30 µm range. SEM/energy-dispersive X-ray spectroscopy (EDS) analysis showed the presence of a hard and brittle intermetallic compound of Al and FeAl3 (with 770–800 HV). The microhardness of the AlMg6-titanium bimetal grew higher closer to the weld interface and reached 207 HV (for AlMg6) and 340 HV (for titanium). Both bimetals had average tear strength below 100 MPa. However, the tear strength of some specimens reached 186 and 154 MPa for AlMg6-titanium and AlMg6-stainless steel, respectively. It is also worth mentioning that heat treatment at 200 °C for one hour led to a uniform distribution of tear strength along the entire length of the bimetals. The study shows that one of the possible solutions to the problem of the formation of the brittle intermetallic compounds would be the use of intermediate layers of refractory metals.

Nauk. visn. nat. hirn. univ.

“…The information processing system includes an operator and an information processing unit, which consists of an auto matic protection and signaling board and a board of the infor mation and computer complex [13,14].…”

mentioning

confidence: 99%

Increasing the sensitivity of measurement of a moisture content in crude oil

Osadchuk¹,

Семенов²,

Zviahin³

et al. 2020

Purpose. Investigation of a moisture frequency transducer based on a moisture-sensitive capacitive element of a cylindrical structure with mesh electrodes for a system for measuring the amount and parameters of crude oil. Methodology. When constructing a moisture-sensitive element, an oscillatory method for measuring humidity was applied to achieve high sensitivity and accuracy while maintaining a low cost of the device. A moisture sensitive capacitive sensor based on a cylindrical structure with mesh electrodes was introduced into the measuring generator system based on a transistor structure with a negative differential resistance. Findings. Analytical expressions are obtained to describe the dielectric constant of an inhomogeneous mixture of water and oil. Using these equations, the capacitance of a moisture-sensitive sensor with mesh electrodes is calculated as a dependence of the moisture content of crude oil. It was determined that the capacitance of the moisture sensitive sensor increased from 20 to 44 pF when the mass moisture of crude oil changed from 0 to 30%. The sensitivity of the developed capacitive sensor is 0.8 pF/% when using a measuring device in the form of a crude oil pipeline with a diameter of 50 millimeters. Originality. A mathematical model has been developed for the primary transducer of the moisture content of crude oil based on a cylindrical capacitor structure with net-like electrodes, which allows determining the value of the capacitance of the primary transducer of the moisture content of crude oil. A self-oscillator device for controlling the moisture content of crude oil has been developed on the basis of the structure of bipolar and field-effect transistors with a cylindrical capacitor structure with mesh electrodes. Practical value. Circuitry solutions for a moisture transducer for crude oil have been developed. The results of experimental studies showed that for the selected version of the moisture converter circuit, the output signal frequency decreased in the range from 1.617 to 1.27 MHz with a change in the mass moisture content of the Turkmen mixture from 0 to 30%, respectively, and is close to a linear dependence. The wide frequency range of the output signal of the secondary converter with the frequency output of the measured information increases the accuracy of moisture measurement in crude oil by an order of magnitude.