Mario Orozco - Academia.edu (original) (raw)

Papers by Mario Orozco

Materials research express, Aug 1, 2019

This paper assesses the microstructure, porosity, microhardness (Hv ) and fracture toughness (K C... more This paper assesses the microstructure, porosity, microhardness (Hv ) and fracture toughness (K C ) of cemented carbides coatings deposited by High-Velocity Oxygen Fuel (HVOF) and Flame (FSFC) spray processes. Three types of coatings were applied for each process from similar feedstock materials in powder and cored wire form. Measurements of fracture toughness were conducted with the Vickers indentation method in the cross section of the deposited layers. An image processing system was applied for the analysis of porosity, showing a globular morphology of the pores in both processes. The experimental results allowed corroborating that the coatings applied by HVOF using powder feedstock have lower porosity than those achieved with the Flame Spray of cored wire material (FSFC). In HVOF and FSFC processes, the porosity of the coating could be an important factor, but when kept in low values, the decrease in Hv and K C are mainly related to the microstructural changes in the coating. The results also allow considering the FSFC technique as a feasible alternative particularly in applications such as internal part of industrial pipes where it becomes difficult to use HVOF due to accessibility problems.

Research Square (Research Square), Nov 14, 2022

The International Journal of Advanced Manufacturing Technology, Oct 22, 2018

Using response surface methodology, optimization of friction stir spot welding process parameters... more Using response surface methodology, optimization of friction stir spot welding process parameters of dissimilar Al 5083 and C 10100 joints were experimented. The predominant requirement was to obtain reduced interface hardness and increased tensile shear failure load. For specification of experimental conditions, central composite design matrix was used, with three factors and five levels. With Al 5083 alloy and C 10100 copper twenty joints were made. Experimentally, tensile shear failure load and interface hardness were measured. Significant main parameters and interaction process parameters were evaluated using analysis of variance (ANOVA) method. Regression analysis was used for development of empirical relationship. Design expert software was used for optimization of friction stir spot welding process parameters by using response graphs and constructing contour plots. At 95% confidence level, prediction of tensile shear failure load and interface hardness of the dissimilar Al 5083-C 10100 joints were done using the empirical relations that were developed. The optimum conditions of Al 5083-C 10100 joints by friction stir spot welding process were evaluated using contour plots.

This work presents the analysis and development of the TIG-MIG hybrid welding process based on th... more This work presents the analysis and development of the TIG-MIG hybrid welding process based on the analysis of the voltage and current signals generated during the metal transfer. The effect of the parameters on the stability of the process is evaluated using on stated stability indices. The stability indices evaluated showed little variation between them with respect to the stability classification by experimental conditions. A comparative analysis of stable and unstable conditions is developed based on images of the bead, arc current and voltage signals, y the time frequency diagram. Finally, the visual inspection of the weld beads and a statistical analysis for the validation of the obtained experimental results are carried out. As a result of the research, the effectiveness of the method used for stability analysis in hybrid TIG-MIG welding processes in the manufacturing area was demonstrated.

The International Journal of Advanced Manufacturing Technology, Mar 24, 2023

Thermal spray, May 10, 2016

Dyna-colombia, Mar 28, 2022

This paper studies the influence of zinc coating of galvanized DP600 steel (DP600G) on nugget dev... more This paper studies the influence of zinc coating of galvanized DP600 steel (DP600G) on nugget development and on the mechanical properties of dissimilar DP600-AISI304 welded joints obtained by resistance spot welding process (RSW). RSW evaluations consisted of determining, from the dynamic resistance curves, the different stages involved in nugget formation. The experimental results showed that zinc coating on the DP600G steel has a significant influence on the time needed for the start of nugget formation, producing a two times longer delay for nongalvanized steel. Expulsion time was delayed by 1.12 times. The presence of Zn in DP600G/AISI304 welded joints produced smaller nugget diameters as compared to the DP600/AISI304 joints for the same experimental conditions; however, higher peak failure load values were obtained for the former. The causes of this unusual behavior are also analyzed in this paper.

Journal of Materials Engineering and Performance

Sensors (Basel, Switzerland), 2020

This research proposes a new index to evaluate the stability of the melting process, in three-pha... more This research proposes a new index to evaluate the stability of the melting process, in three-phase electric arc furnaces (EAFs), based on the acoustic signals generated during the different stages of the casting. The proposed stability index is obtained by characterizing the time and frequency domain of the acoustic signals. During EAF monitoring, acoustic signals were acquired using a microphone coupled to an NI USB-9234 acquisition system. To validate the results, the voltage and current signals were measured with the aid of a Circutor AR6 power analyzer for three-phase electrical networks. The results showed that the acoustic signal energy in the frequency range of 1 to 12 kHz can be used as an indicator of the process stability in the EAF. Finally, the validity of the proposed stability index is evaluated from the process characterization using the harmonic distortion analysis methods and the dynamic U-I characteristics of the arc voltage and current signals. The results obtain...

Ceramics International, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

The International Journal of Advanced Manufacturing Technology, 2019

A new proposal for evaluating the relationship between the energy of vibration signals produced b... more A new proposal for evaluating the relationship between the energy of vibration signals produced by a friction stir spot welding process and mechanical properties of dissimilar AA1050 H24 aluminum alloy-Cu lap joints is presented here. We characterized the vibration signals during the FSSW process to correlate them with microhardness and the failure load of the joints. The influences of dwell time and tool rotation speed on the mechanical properties of the join and its correlation with the energy of the vibration signals were studied. Macro images and microhardness maps of welds were also produced. The strong correlation found confirms that the energy of the vibration signals on the Z and Y axes can be used as an indicator of mechanical properties and as a novel method for weld evaluation. Finally, results based on numerical predictions are compared with the experimental failure load. The mathematical model obtained to calculate failure load values based on friction stir spot welding process parameters, also including the energy of vibration signals, improves the fit from 74.3% (with analyzed process parameters only) to 93.8% with the addition of the energy of the signal.

This paper researches the effect of zinc coating of galvanized DP600 steel on the dynamic resista... more This paper researches the effect of zinc coating of galvanized DP600 steel on the dynamic resistance and the delayed nugget formation of dissimilar DP600 - AISI304 welded joints, obtained with resistance spot welding process (RSW). The RSW evaluations consisted of determining, from the dynamic resistance curves, the time involved in the different stages of the process, particularly the beginning of nugget formation. The experimental results showed that, from the dynamic resistance curves, it is possible to identify 8 distinct stages during the welding of galvanized DP600 steel and AISI304 stainless steel. In the case of the welding of uncoated DP600 steel with AISI304, only 6 stages are identified (except for stages 2 and 3), which are directly related to the heating, softening and melting of the galvanic coating. The energy used in stages 2 and 3, causes a delay in the beginning of nugget formation for welded joints obtained with galvanized DP600 steel compared to uncoated DP600 - ...

DYNA

Este trabajo investiga el comportamiento del desgaste en mezclas erosivas de recubrimientos depos... more Este trabajo investiga el comportamiento del desgaste en mezclas erosivas de recubrimientos depositados mediante la técnica de proyección térmica usando el proceso HVOF. Se analizaron tres tipos de recubrimientos, WC-CoCr con estructura de grano fino, Cr3C2-NiCr 75-25 y NiCrWSiFeB, estos últimos con tamaños de grano convencional. Los ensayos de desgaste erosivo se desarrollaron usando un tribómetro de recipiente de mezclas para evaluar la resistencia a la erosión de los recubrimientos a velocidades de impacto de 3.61 m/s y 9.33 m/s y ángulos de impacto de 30 y 90º. El mecanismo de desgaste de los recubrimientos fue estudiado y discutido sobre la base del examen microestructural y la influencia de sus propiedades mecánicas. Se observó que el recubrimiento de carburo de tungsteno exhibe mejor resistencia a la erosión comparada con los recubrimientos de carburo de cromo y metálico debido a sus propiedades de microdureza, tenacidad a la fractura y menor porosidad.

DYNA INGENIERIA E INDUSTRIA, 2013

• This paper presents a study to evaluate the relationship between the tool design and vibroacous... more • This paper presents a study to evaluate the relationship between the tool design and vibroacoustical signals of friction stir welding process in the aluminum AA1050. The

An artificial neural network (ANN) analysis is used to obtain a model to predict the rate of eros... more An artificial neural network (ANN) analysis is used to obtain a model to predict the rate of erosive wear of hard coatings deposited by two different kinds of thermal spray techniques. High Velocity Oxygen Fuel (HVOF) and Flame Spray FlexiCords (FS/FC) techniques were used under various operational conditions. Different microstructural features that control the mechanical and the tribological performances of three groups of deposits: tungsten carbide, chromium carbide and metallic alloy coatings, were analyzed. The ANN technique involves database use to predict erosive wear evolution, having a large number of variables like deposition process, impingement angles and velocity of the erosive particles, porosity, roughness, microhardness and fracture toughness. Commercially available powders were used as feed-stock for coatings deposited by HVOF. Commercial cord wires were used in the FS/FC coating deposition. The slurry erosion testing was performed using a laboratory made pot-type slurry erosion tester, at impact velocity of 3,61 m/s and 9,33 m/s combined with impact angle of 30° and 90°. From the results, it was observed that the microhardness and fracture toughness, as a combination factor, have the greatest influence on erosive rate followed by porosity. Samples coated with WC-CoCr cermet coating with fine WC carbides exhibit higher erosion resistance as compared with the other conventional cermet and metallic alloy coatings, mainly because of its homogenous microstructure and improved properties like low porosity, high microhardness and high fracture toughness. The numerical results obtained via neural network model were compared with the experimental results. The agreement between the experimental and numerical results is considered a good aspect.

Metallurgical and Materials Transactions A, 2017

Science and Technology of Welding and Joining, 2013

This paper presents a mathematical model to predict the tensile strength (TS) of friction-stir we... more This paper presents a mathematical model to predict the tensile strength (TS) of friction-stir welded (FSW) AA1050 aluminium alloy joint. This model has been obtained from the optimisation of the parameters of models developed from vibro-acoustic signals produced during the process. The multiple response method was used to obtain the optimisation model. During experimental development, the process parameters selected to be assessed were rotation speed (RS), travel speed, and tool profile (TP). The TS of the welded joint and the root mean square (RMS) value of the vibro-acoustic signal in the frequency range of 3?2-6?4 kHz were analysed as response variables. In order to validate the model, the optimal values of the factors and responses are presented, showing their agreement with the experimental values obtained. This model can be used to develop and optimise the parameters of the automatic control of the FSW process, based on the vibro-acoustic signal generated.

Dyna (Spain), 2013

This paper presents a study to evaluate the relationship between the tool design and vibroacousti... more This paper presents a study to evaluate the relationship between the tool design and vibroacoustical signals of friction stir welding process in the aluminum AA1050. The