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Garcia-Vazquez F.,Corporacion Mexicana de Investigacion en Materiales | Aguirre A.,Corporacion Mexicana de Investigacion en Materiales | Hernandez-Garcia H.M.,Corporacion Mexicana de Investigacion en Materiales | Santiago-Bautista L.,Corporacion Mexicana de Investigacion en Materiales | And 2 more authors.
Materials Science Forum | Year: 2013

Plasma Transferred Arc (PTA) process is increasingly used in applications where enhancement of wear, corrosion and heat resistance of metals surface is required. The shape of weld bead geometry affected by the PTA welding process parameters is an indication of the quality of the weld. PTA is a versatile method of depositing high-quality metallurgically fused deposits on relatively low cost surfaces. The overlay deposited is an alloy that is hard and more corrosion resistant than counterparts laid down by Gas Tungsten Arc Welding (GTAW) or Oxy Fuel Welding (OFW) processes. Weld deposits are characterized by very low levels of inclusions, oxides, and discontinuities. This process produces smooth deposits that significantly reduce the amount of post weld machining required. Metal-Mechanic industry continuously requires recovering tool steel components subjected to severe wear. The steel known as D2 is considered to be a high carbon, high chromium cold work tool steel. In this research, weld beads were deposited on D2 steel by using PTA process with different parameters as welding current and travel speed using base nickel filler metal. In order to evaluate the metallurgical features on the weld beads/substrate interface a microstructural characterization was performed by using Scanning Electron Microscopy (SEM) and to evaluate the mechanical properties was conducted the wear test. © (2013) Trans Tech Publications, Switzerland.

Bustos Z.L.L.,Corporacion Mexicana de Investigacin en Materiales COMIMSA | Vazquez F.J.G.,Corporacion Mexicana de Investigacin en Materiales COMIMSA | Medina G.Y.P.,Corporacion Mexicana de Investigacin en Materiales COMIMSA | Arista B.V.,Corporacion Mexicana de Investigacin en Materiales COMIMSA | Cortez V.H.L.,Tlalnepantla Institute of Technology
Materials Research Society Symposium Proceedings | Year: 2015

The wear phenomenon may occur for a variety of work conditions in the material. It causes losses in terms of time and costs in the components which are used for heavy machinery due to its re-pair or even replacement. It is important to select suitable materials that ethibit high-quality weldability and resistance to abrasive wear such as the high strength low alloy (HSLA) steel grade 950A. Therefore, it is necessary to study the wear behavior of this kind of steel after components are joined by multi-pass gas metal arc welding (GMAW) process, specifically on the heat affected zone (HAZ). The aim of this research was to evaluate wear resistance by pin on disc test and hardness on heat affected zone of HSLA steel plates with thickness of 14 mm joined by using GMAW process varying different parameters as wire feed speed and voltage. The influence of microstructural features such as carbide precipitation on wear behavior and hardness was investigated using optical microscopy (OM) and scanning electron microscopy (SEM). The results show that microstructure is modified by the heat input of the welding process, affecting the material pmperties and causing more susceptibility to wear on the welded area. © 2015 Materials Research Society.

Vargas-Arista B.,Tlalnepantla Institute of Technology | Gomez-Morales M.A.,Tlalnepantla Institute of Technology | Garfias-Garcia E.,Area de Ingenieria de Materiales | Garcia-Vazquez F.,Corporacion Mexicana de Investigacion en Materiales
Advanced Materials Research | Year: 2014

Two fractured pins of impact wrench were evaluated by fractography using scanning electron microscopy. This pneumatic wrench is used to the fabrication of automotive components being characterized by its power and tightening capacity. The important part of the wrench is the pin clutch impact mechanism used to generate high torque. An original pin manufactured with AISI E52100 steel adjusted 2, 580 nuts before fracture and a substitute pin of E52100 modified steel with S adjusted 7, 095 nuts before failure. Fractographic analysis in both fracture surfaces indicated a ductile-brittle mixed fracture mode. Original pin surface exhibited a granular appearance while substitute pin surface showed fibrous and rough morphology. Precipitation of nearly rounded, elliptical and elongate second-phase particles containing Cr, C and Mn measured as intergranular and transgranular particle density was observed, promoting some brittle failure zones and ductile fracture measured as the volume fraction of grain boundaries and microvoids, respectively. A larger amount of intergranular medium precipitates was found on the original pin which favored the brittle failure among the grain boundaries compared to that of the substitute pin. The ductile fracture by larger transgranular fine particle density which acted as nucleation sites of higher volume fraction of microvoids was found in the substitute pin. © (2014) Trans Tech Publications, Switzerland.

Vargas-Arista B.,Tlalnepantla Institute of Technology | Albiter A.,Mexican Institute of Petroleum | Garcia-Vazquez F.,Corporacion Mexicana de Investigacion en Materiales | Mendoza-Camargo O.,Tlalnepantla Institute of Technology | Hallen J.M.,IPN ESIQIE
Revista de Metalurgia | Year: 2014

A characterization study was done to analyze how microstructural regions affect the mechanical properties, corrosion and fractography of the Heat Affected Zone (HAZ), weld bead and base metal for pipe naturally aged for 21 years at 30 °C. Results showed that microstructures exhibited damage and consequently decrease in properties, resulting in over-aged due to service. SEM analysis showed that base metal presented coarse ferrite grain. Tensile test indicated that microstructures showed discontinuous yield. Higher tensile strength was obtained for weld bead, which exhibited a lower impact energy in comparison to that of HAZ and base metal associated with brittle fracture by trans-granular cleavage. The degradation of properties was associated with the coarsening of nano-carbides observed through TEM images analysis, which was confirmed by SEM fractography of tensile and impact fracture surfaces. The weld bead reached the largest void density and highest susceptibility to corrosion in H2S media when compared to those of the HAZ and base metal. © 2014 CSIC.

Garcia-Vazquez F.,Corporacion Mexicana de Investigacion en Materiales | Hernandez-Garcia H.M.,Corporacion Mexicana de Investigacion en Materiales | Vargas-Arista B.,Tlalnepantla Institute of Technology | Aguirre A.,Corporacion Mexicana de Investigacion en Materiales | Granda-Gutierrez E.E.,Corporacion Mexicana de Investigacion en Materiales
Advanced Materials Research | Year: 2014

Among the different surface treatments used to improve the wear resistance of metallic materials, plasma transferred arc (PTA) is an attractive alternative to conventional techniques due to the intrinsic properties of its higher deposition rate, lower heat input and especially for the wide applicability of materials. The wide range of materials makes it possible to produce metallurgical bonding between the hardfacing layer and substrate material with very low dilution and distortion. Weld deposits are characterized by less level of inclusions, oxides, discontinuities and wear resistance. Metal-mechanic industry continuously requires recovering tool steel components subjected to severe wear. In this research Fe-based filler metal was deposited on D2 steel by using plasma transferred arc (PTA) process. The influence of Cr and Nb on Fe-based filler metal microstructure was investigated using scanning electron microscopy (SEM). In order to evaluate the mechanical properties were performed wear and hardness tests. The wear resistance and hardness values were compared with the results of a weld bead using nickel-based filler metal. © (2014) Trans Tech Publications, Switzerland.

Vargas-Arista B.,Tlalnepantla Institute of Technology | Balvantin A.,CINVESTAV | Baltazar A.,CINVESTAV | Garcia-Vazquez F.,Corporacion Mexicana de Investigacion en Materiales
Materials Science and Engineering A | Year: 2012

In this paper, artificial aging of welded joints of an API 5L X52 steel pipeline was studied using ultrasonic spectral analysis. The joints were welded using submerged arc welding process and isothermally aged at 250 °C for different time intervals. Ultrasonic measurements were carried out using a high precision water immersion ultrasonic scanner which produces C-scan maps of the tested weld samples. The results of these measurements show that ultrasonic velocity was not significantly affected by aging time; only small variations were detected associated with the degradation of strength and hardness properties. On the other hand, ultrasonic attenuation measurements were more sensitive to aging in both the weld pool and base metal. An increase in the attenuation coefficient during early aging time was linked to the precipitation of fine nanocarbides and an increase in ferrite grain size. After 200. h of aging time, the attenuation coefficient decreased monotonically, this was found to be related to the nanoparticle coarsening and ferrite grain growth after long periods of over-aging time. This phenomenon was larger in the weld pool than in the base metal due to a higher increase in carbide precipitations and their lower coarsening. These results could lead to the development of a non-destructive testing method for monitoring degradation of welded pipelines having extensive years of service under over-aging conditions. © 2012 Elsevier B.V.

Gomez-Vargas O.A.,Monterrey Institute of Technology | Solis-Romero J.,Tlalnepantla Institute of Technology | Figueroa-Lopez U.,Monterrey Institute of Technology | Ortiz-Dominguez M.,Autonomous University of the State of Hidalgo | And 2 more authors.
Materials Letters | Year: 2016

To alleviate spallation and crack difficulties exhibited by a borided metallic surface when it is subjected to a normal, heavy and sliding load under dry conditions, a boron nitride coating was produced on pure iron in two stages: boriding the iron surface at 950°C for 6 h and then nitriding the pre-borided iron at 550°C for 6 h. The powder-pack technique was used in both stages. XRD measurements confirmed that the grown layers were nitrides and duplex borides. The produced diffusion of the layers reached 240 μm in depth as measured by SEM images. The measured microhardness across the case favoured the interphase cohesion between the iron nitrides and iron borides layers. Consequently, the multicomponent coating exhibited superior wear resistance to an applied normal load under dry sliding contact conditions in comparison to borided iron. © 2016 Elsevier B.V. All rights reserved.

Mendoza O.,Justo Sierra University | Vargas B.,Tlalnepantla Institute of Technology | Mendoza J.,CINVESTAV
IEEE Latin America Transactions | Year: 2013

Digital processing on fractographic images of fracture surfaces was performed, for the weld metal aged at 250 ; C for 500 and 900 hours. The digital analysis on fractographs was carried out using mathematical morphology and morphological transformation in order to gain specific structures of the images. The results showed that the mechanism of growth and coalescence of microcavities can be observed during the fractographic image segmentation. © 2003-2012 IEEE.

Solis Romero J.,Tlalnepantla Institute of Technology | Medina Flores A.,Tlalnepantla Institute of Technology | Roblero Aguilar O.,Tlalnepantla Institute of Technology | Oseguera Pena J.,Monterrey Institute of Technology
Superficies y Vacio | Year: 2013

The influence of nitriding time and applied load in the friction-wear behaviour of an H13 steel has been studied. Weakly ionised plasma unit and a postdischarge plasma reactor were used for nitriding the H13 die steel with variations of nitriding time from 5h to 9h (at 500 °C). Optical microscopy and microhardness deep profiles of the nitrided layer were obtained for each nitriding time. Standard pin-on-disc wear test were conducted at ambient temperature (18-23 °C) and dry sliding. It was observed that the higher the nitriding time, the lower the friction coefficient variations and wear rate varied as a function of the applied load. Plastic deformation and abrasion wear resulted to be the main wear mechanism for short sliding distances, while for long sliding distances plastic deformation dominated the wear mechanism and to some extent oxidative wear. The compound layer (white layer) was central for wear and load capacity.

Vargas-Arista B.,Tlalnepantla Institute of Technology | Romero J.S.,Tlalnepantla Institute of Technology | Angeles-Chavez C.,Mexican Institute of Petroleum | Albiter A.,Mexican Institute of Petroleum | Hallen J.M.,Laboratorios Pesados Of Metalurgia
International Journal of Electrochemical Science | Year: 2011

Corrosion behavior of welded joints in API5L-X52 pipe steel aged at 250 °C at different times was investigated under electrochemical technique like tafel polarization, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies. The electrochemical results which were performed in a solution of brine containing hydrogen sulfide at 25 °C, revealed an increase of the general corrosion rate in the weld bead, the heat affected zone and the base metal as the aging time was elapsed. The corrosion rate higher was linked to the transgranular precipitation of fine nanoparticles of cementite and niobium carbide ocurred during accelerated aging process until 500 hours and their coarsening process after this time. The SEM study of the corrosion products at the three different zones showed the presence of oxide and sulphur of iron very brittle and porous on metallic surface. The highest corrosion rate was reached by the weld bead owing to the largest increase in the amount of nanocarbides, lesser coarsening and the presence of corroding products with larger brittleness and porosity. © 2011 by ESG.

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