Laser treatment of dual matrix structured cast iron surface: Corrosion resistance of surface

doi:10.1016/j.optlaseng.2014.07.008

Optics and Lasers in Engineering

Volume 64, January 2015, Pages 17-22

https://doi.org/10.1016/j.optlaseng.2014.07.008 Get rights and content

Highlights

•
A dense layer with fine grains is formed and partially dissolve SiC particles are observed.
•
Martensitic phases with a fatherly like structure are formed below surface.
•
The martensite is transferred to ferritic–pearlitic structures in the molten zone.
•
Corrosion resistance of treated surface improves significantly.
•
The presence of fine grains in dense layer and formation of nitride compounds contribute to the corrosion resistance.

Abstract

Laser gas assisted treatment of dual matrix structured cast iron surface is carried out and the corrosion response of the surface is examined. A carbon film containing 15% SiC particles and remaining 85% carbon are formed at the workpiece surface prior to the laser treatment process. The formation of carbon film enhances the absorption of the incident laser beam and accommodates uniformly the SiC particles at the workpiece surface. Nitrogen at high pressure is used as an assisting gas during the laser treatment process. Metallurgical and morphological changes in the laser treated layer are examined using a scanning electron microscope, energy dispersive spectroscopy, and X-ray diffraction. Electrochemical tests are carried out to measure the corrosion response of the laser treated and untreated workpiece surfaces. It is found that laser treatment results in a dense layer consisting of fine grains, partially dissolved SiC, and nitrogen compounds in the treated region, which improves corrosion resistance of the laser treated workpiece surface.

Section snippets

Inroduction

Iron base composites are one of the important candidates for low cost composites with high wear and corrosion resistance [1]. The composite material with iron matrix and hard particle reinforcement has superior properties such as hardness, fracture toughness, and wear resistance. Depending on hard particle size, shape, and concentration, surface properties of the iron matrix composite changes [2] while limiting its practical applications. Iron based composites are generally formed from the

Experimental

The material used in the present study was dual matrix structured cast iron. The chemical composition of the material is shown in Table 1. To produce dual matrix structures (DMS) with different ausferrite volume fractions (AFVF), as cast specimens were intercritically austenitized at the dual phase region of 810 °C for 90 min and then rapidly transformed to a salt bath containing 50% KNO₃+50% NaNO₃ held at 315 °C and 375 °C for austempering for 120 min. The details of the heat treatment process are

Results and discussion

Laser controlled melting of dual matrix structured iron based alloy with the presence of 15% SiC particles at the surface was carried out. Morphological and metallurgical changes in the laser treated layer were examined using the analytical tools. The corrosion resistance of the laser treated surface was determined incorporating the electrodynamic tests.

Conclusion

Laser controlled melting of dual phase matrix cast iron was carried out. The dual matrix structures (DMS) with different ausferrite volume fractions (AFVF) were formed through intercritically austenitizing at the dual phase temperature region for 90 min and later austempering at 315 °C and 375 °C for 120 min. A carbon film containing 15% SiC particles and remaining 85% carbon was formed prior to the laser treatment process. A carbon film provided increased absorption of the incident laser beam and

Acknowledgments

The authors acknowledge the support of Dean of Scientific Research for funded Project (SF131-CES-12), King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia for this work.

References (22)

B.S. Yilbas et al.
Laser gas assisted treatment of AISI H12 tool steel and corrosion properties
Opt Lasers Eng
(2014)
G. Azimi et al.
Effects of silicon content on the microstructure and corrosion behavior of Fe–Cr–C hardfacing alloys
J Alloys Compd
(2010)
X.H. Tang et al.
Microstructure of high (45 wt%) chromium cast irons and their resistances to wear and corrosion
Wear
(2011)
C. Cetinkaya
An investigation of the wear behaviours of white cast irons under different compositions
Mater Des
(2006)
M.M. Oghbaei et al.
Microwave versus conventional sintering: a review of fundamentals, advantages and applications
J Alloys Compd
(2010)
S.M. Reshetnikov et al.
Corrosion electrochemical behavior of iron based composite layers obtained by laser sintering
Prot Metals Phys Chem Surf
(2011)
G. Nesher et al.
An Fe(CO)5-thermolysis-based process for the preparation of polymer and iron composite powders with high corrosion resistance
Eur J Inorg Chem
(2012)
M. Asif et al.
Development of iron based brake friction material by hot powder preform forging technique used for medium to heavy duty applications
J Miner Mater Charact Eng
(2011)
M.J. Dutta et al.
Studies on compositionally graded silicon carbide dispersed composite surface on mild steel developed by laser surface cladding
J Mater Process Technol
(2008)
Y.L. Saraswathi et al.
A comparative study of corrosion behavior of Al/SiCp composite with cast iron
Corrosion
(2001)

Z-L. Song et al.

Microstructure of SiC particles reinforced Fe-based alloy composite coating

Trans Mater Heat Treat

(2011)

Cited by (23)

Influence of laser parameters on graphite morphology in the bonding zone and process optimization in gray cast iron laser cladding
2019, Optics and Laser Technology
The surface modification of gray cast iron through laser cladding produces a high-performance surface with low-cost materials, thereby reducing the manufacturing cost. This approach may considerably alter the phases in the bonding zone. In turn, the morphology of the graphite and adjacent phases influence the reliability and surface performance of the cladding layer. To optimize this process, this study performed numerical analysis and cladding experiments to analyze the carbon atom diffusion in graphite and examine the effects of scanning speed and laser power on graphite environment temperature, structural transformation, and graphite morphology in the bonding zone. The results showed that, in the case of constant laser power, as the scanning speed decreased, the diffusion of carbon atoms increased and became highly refined, thereby inhibiting poor graphite morphology and reducing micro-crack generation. At a constant scanning speed, the laser power slightly influenced the structure and macro-morphology of graphite. Considering the macro-morphology in the cladding layer and the micro-cracks in the bonding zone into consideration, we proposed that a laser power of 350 W and a scanning speed of 300 mm/min are the optimal process parameters.
Effect of rare earth oxide nano-additives on the corrosion behavior of Fe-based hardfacing alloys in acid, near-neutral and alkaline 3.5 wt.% NaCl solutions
2018, Applied Surface Science
Citation Excerpt :
The values of the equivalent circuit elements are shown in Table 7. The high Rct indicates that the hardfacing specimens have superior corrosion resistance[32,33]. The Rcts of the hardfacing specimens with nano-additives are higher than that of the hardfacing specimen without nano-additives.
In this paper, effect of rare earth oxide nano-additives on the corrosion behavior of Fe-based hardfacing alloys was studied. The corrosive solutions were 3.5 wt.% NaCl + 0.01 mol/L HCl solution, 3.5 wt.% NaCl solution and 3.5 wt.% NaCl + 0.01 mol/L NaOH solution. The deep-etched microstructure of the hardfacing alloys was observed. The potentiodynamic polarization curves and electrochemical impedance spectra were used to study the corrosion behavior of the hardfacing alloys. The polarization test results showed that nano-additives shifted the corrosion potentials of the hardfacing alloys towards the noble direction in corrosive solutions. The values of the equivalent circuit elements for the impedance spectra of the hardfacing alloys indicated that nano-additives increased the corrosion resistance of the hardfacing alloys. When the content of nano-additives was 0.3 wt.%, the hardfacing alloy possessed the maximum charge transfer resistance in acid NaCl solution. The hardfacing alloy with 0.6 wt.% nano-additives had the maximum charge transfer resistance in near-neutral and alkaline NaCl solutions. The change in volume fraction of the primary and eutectic carbides and refinement of primary carbide influenced the corrosion behavior of the hardfacing alloys.
Impact analysis of the thermal mechanical coupling characteristics of graphite morphologies during laser cladding of gray cast iron
2017, Optics and Laser Technology
Citation Excerpt :
On account of the inherent characteristics of cast iron materials, the local restoration cost is typically high, and most damaged equipment should be directly scrapped. Hence, laser cladding technology should be used to improve the surface properties of equipment and directly prolong its service time effectively [1], which have significant industrial application values. Laser cladding can strengthen equipment surfaces, such as large-scale box and revolving drum.
Cladding and numerical experiments on thermodynamic coupling were conducted to determine the thermal response features and microcracks of graphite and environment phases during surface laser cladding of gray cast iron. A micromodel of graphite–environment phase was established using numerical methods. On the basis of this model, a quantitative analysis on the thermal mechanical coupling characteristics of microstructures was realized, the relationship with microcracks at tip of graphite was established, and the influence of morphological difference on local stress concentration was obtained. Results showed considerable stress concentration at the tip of graphite during cooling stage, and on the whole, the stress concentration at both ends of graphite was in direct proportion to the length of the graphite. Moreover, sufficiently short graphite resulted in further increase in stress concentration. The influence caused by tip angle was more considerable than that of length, and sharpness was in direct proportion to stress concentration. For stress fields at both ends of dimer graphite, collinear distribution easily caused stress concentration, and more obvious stress concentration was observed when the two tips were closer. The interactive effect was weak and the influence on stress concentration was minimal when two graphite pieces were in parallel or vertical distribution.
Effect of rare earth oxide nano-additives on micro-mechanical properties and erosion behavior of Fe-Cr-C-B hardfacing alloys
2017, Journal of Alloys and Compounds
Citation Excerpt :
Rare earth oxides (oxides of Ce and La) increased volume fraction of carbide of Fe–Cr–C hardfacing coating [11]. Based on the present research, nano-particles containing rare earth oxides have given investigators a new idea to improve erosion resistance performance of high chromium cast iron hardfacing alloys regarding to their excellent properties [12,13]. In this paper, Fe-Cr-C-B hardfacing alloys with different content of rare earth oxide nano-additives were prepared on Q235 steel substrates by using arc welding.
In this paper, the effect of rare earth oxide nano-additives on micro-mechanical properties and erosion behavior of Fe-Cr-C-B hardfacing alloys was studied. Optical microscope was used to observe microstructure of hardfacing alloys. X-ray diffractometer was used to analyze phases of hardfacing alloys. Vickers micro-hardness tester was used to measure micro-hardness of constitutional phases. Fracture toughness (K_IC) of primary carbide was calculated by indentation method. Erosion tests were carried out using JZB sand blaster. The experimental results showed that hardfacing alloys were hypereutectic, which were composed of M₇C₃, martensite and retained austenite. Nano-additives increased the hardness and the K_IC of primary carbide. The hardness of the primary carbide in the hardfacing alloy with 0.288 wt% nano-additives reached a maximum of 1716.54HV_0.2. The K_IC of the primary carbide in the hardfacing alloy with 0.432 wt% nano-additives was 9.27 MPa√m, which increased by 51.7% than that of the primary carbide in the hardfacing alloy without nano-additives. Erosion test results showed that nano-additives improved the erosion resistance of hardfacing alloys. The erosion rate of the hardfacing alloy with 0.432 wt% nano-additives decreased by 31.8% than that of the hardfacing alloy without nano-additives.
Heat transfer enhancement of ammonia spray cooling by surface modification
2016, International Journal of Heat and Mass Transfer
Citation Excerpt :
The ammonia spray cooling combined with enhanced surface can improve the critical heat flux significantly up to 910 W/cm2 [52], showing excellent heat removal capacity. Besides the extremely low temperature (or hash environment defined by Ohadi and Qi [55]), the surface for heat transfer will potentially face with corrosion, thus requiring corrosion-resistance treatment [56]. To date, the effect of surface corrosion on heat removal has rarely been reported.
This study presented a scenario for spray cooling in cryogenic applications. Liquid ammonia was employed for spray cooling through a two nozzle array. Three groups of modified surfaces were experimentally tested. The first group of surfaces included three surfaces treated by electrochemistry at different levels. The second group comprised of two surfaces coated by micro copper particles in different sizes. The final group composed two hybrid surfaces combining microporous coating with macro channels. A heat flux of about 350 W·cm⁻² was obtained in this work and discrepancies in spray cooling performance for these surfaces were reported. It was found that the hybrid surface possessed the best heat removal capacity. During spray cooling, it showed a small temperature rise of 2.3 °C when heat flux increased from 100 W·cm⁻² to 300 W·cm⁻². Comparatively, the reference surface presented a temperature rise of 25.3 °C in the same condition. The results indicated that surface modification enhanced the spray cooling performance by virtue of (i) larger specific surface area and (ii) higher boiling sites density. The present study paves the way to further cryogenic applications and provides an insight for the surface modification targeting heat transfer enhancement.
Laser treatment of dual matrix cast iron with presence of WC particles at the surface: Influence of self-annealing on stress fields
2016, Optics and Laser Technology
Citation Excerpt :
Although laser surface treatment of alloys were studied previously [17,18], the main focus was to examine the surface morphology when hard particles were present and the microhardness in the laser treated layer. In addition, the corrosion resistance of the laser treated surface due to the presence of SiC particles is investigated in the previous study [19] and the mechanical properties including microhardness, residual stress, and friction coefficient of the surface were left for the future study. Thermal stress analysis and the residual stress formed at the treated surface of the dual matrix cast iron with presence of high concentration of WC were left for the future study.
Laser control melting of dual matrix cast iron surface is carried out. A carbon film containing 15% WC particles is formed at the surface prior to the laser treatment and the spiral tracks are adopted for laser scanning at the workpiece surface. Morphological, metallurgical, microhardness, and scratch resistance of the laser treated surface are examined using analytical tools. Temperature and stress fields in the laser irradiated region are predicted incorporating ABAQUS finite element code. Predictions of temperature and residual stress at the laser treated surface are validated with the thermocouple and the X-ray diffraction data. It is found that surface temperature and residual stress predictions agree well with their counterparts corresponding to thermocouple data and findings of X-ray diffraction technique. Laser treated surface is free from asperities including voids and micro-cracks despite the mismatch of thermal expansion coefficients of WC and dual matrix cast iron. This behavior is attributed to the self-annealing effects of recently formed spiral tracks on the previously formed tracks during the laser treatment process; in which case, the self-annealing effect modifies the cooling rates and lowers thermal stress levels in the laser treated layer. Laser treated layer consists of a dense region composing of fine grains and WC particles, dendritic and featherlike structures below the dense layer, and the heat affected zone.

View all citing articles on Scopus

View full text

Laser treatment of dual matrix structured cast iron surface: Corrosion resistance of surface

Highlights

Abstract

Section snippets

Inroduction

Experimental

Results and discussion

Conclusion

Acknowledgments

Opt Lasers Eng

J Alloys Compd

Wear

Mater Des

J Alloys Compd

Corrosion electrochemical behavior of iron based composite layers obtained by laser sintering

Prot Metals Phys Chem Surf

An Fe(CO)5-thermolysis-based process for the preparation of polymer and iron composite powders with high corrosion resistance

Eur J Inorg Chem

Development of iron based brake friction material by hot powder preform forging technique used for medium to heavy duty applications

J Miner Mater Charact Eng

Studies on compositionally graded silicon carbide dispersed composite surface on mild steel developed by laser surface cladding

J Mater Process Technol

A comparative study of corrosion behavior of Al/SiCp composite with cast iron

Corrosion

Microstructure of SiC particles reinforced Fe-based alloy composite coating

Trans Mater Heat Treat