Thermal Shock on Cylinder Head Induced by High Power Laser

2012 ◽  
Vol 170-173 ◽  
pp. 266-269
Author(s):  
Ming Pang ◽  
Chang Zhen Liu ◽  
Zhi Min Xie ◽  
Guang Hui Xu
Keyword(s):  
Cast Iron ◽  
Thermal Shock ◽  
Cylinder Head ◽  
Ccd Camera ◽  
Optical Microscope ◽  
High Power Laser ◽  
Power Laser ◽  
Fatigue Specimen ◽  
Graphite Cast Iron ◽  
Scanning Electron

Experiment of thermal shock was conducted by laser on cylinder head of graphite cast iron. Infrared pyrometers were mounted on the top of the workbench to sample the transient surface temperatures. The high resolution CCD camera was employed to sample transient images of the cylinder head. Microstructure of thermal shocking specimen was characterized by scanning electron microscopy (SEM) and optical microscope (OM). Mechanical properties of thermal fatigue specimen were evaluated by hardness. Results show that microstructure and hardness are not obviously changed, which mean that cylinder head of graphite cast iron has performance stabilization within the rang of thermal shocking temperature.

Surface Hardening of a Vermicular Cast Iron Used for Integral Molding Valve Seat by High Power Laser

2013 ◽  
Vol 456 ◽  
pp. 474-477
Author(s):  
Ming Pang ◽  
Wei He ◽  
Chang Zhen Liu ◽  
Xu Lan Wang ◽  
Xue Bin Kang
Keyword(s):  
Cast Iron ◽  
High Power ◽  
Laser Processing ◽  
Surface Hardening ◽  
Processing Conditions ◽  
High Power Laser ◽  
Power Laser ◽  
Valve Seat ◽  
Melted Zone ◽  
Scanning Electron

Surface hardening intergal molding valve seat of a vermicular cast Iron was done by Nd:YAG high power laser. The effect of laser parameters on microstructure, hardness and surface quality were conducted by scanning electron microscopy (SEM) ,optical microscopy (OM) and microhardness tester. The results show that The hardening layer of free defect can be obtained with suitable laser processing conditions. The shape of crescent can be observed in the laser hardening layer.The hardening layer consists of melted zone and heat-affected zone.Ledeburite, martensite and remainder austenite can be observed in the melted zone.The heat-affected zone consists of martensite and remainder austenite with retained vermicular graphite.Laser hardening layer has no-uniformity distribution of rigidity due to no-equilibrium calefaction and cooling.The defect of sunen disfigurement can be restrained by reducing heat-input in the ending zone.

Study on Mechanism of Laser Thermal Damage on Piston

2011 ◽  
Vol 228-229 ◽  
pp. 500-504 ◽  
Author(s):  
Ming Pang ◽  
Zhen Tao Liu ◽  
Jian Song Tan ◽  
Xiu Bo Liu
Keyword(s):  
Thermal Shock ◽  
Thermal Damage ◽  
Energy Dispersive Spectrometer ◽  
Intermetallic Phase ◽  
Damage Mechanism ◽  
Laser Damage ◽  
High Power Laser ◽  
Power Laser ◽  
Scanning Electron ◽  
Al Matrix

The experiments of thermal shock damage on piston were conducted by shaped high power laser. Damage mechanism of thermal shock specimen was characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The mechanical properties of thermal shock specimen were evaluated by microhardness. The corresponding mechanisms were discussed in detail. The results show that cracks originated from the interface of Al-matrix and intermetallic phase due to the thermal and mechanical misfit between these brittle components of the microstructure and the surrounding ductile matrix. Oxides of thermal shock crack can accelerate the damage of piston. There is a drop in the hardness of piston at all locations after thermal shock tests.

Effect of Strontium Addition in Graphite Morphology and Nodularization of Hypoeutectic Cast Iron

2020 ◽  
Vol 1000 ◽  
pp. 454-459
Author(s):  
Rahmadi ◽  
Deni Ferdian
Keyword(s):  
Cast Iron ◽  
Image Data ◽  
Optical Microscope ◽  
Spheroidal Graphite ◽  
Data Processing Software ◽  
Graphite Morphology ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
Molten Cast Iron ◽  
Nodular Graphite

Nodular graphite cast iron or known as spheroidal graphite cast iron structurally has a spherical graphite morphology with a matrix consisting of a ferrite-pearlite phase. In general, cast iron has a main alloy consisting of carbon and silicon where both elements have an influence on the potential of graphitization and castability. In this work, the influence of strontium (Sr) added to molten cast iron with a composition of 0, 0.04, 0.06 and 0.08 wt% to graphite morphology were studied. The sample obtained will be carried out a characterization process by observing macro and microstructures using optical microscope equipped with image data processing software that displays graphite fraction, size, form and nodularity. Analysis showed that Sr addition increase in nodularization of graphite from 19.6 % to 31.5% at 0.08 wt% Sr addition.

Surface Melting of Cast Iron With a High Power Laser Beam

1981 ◽  
Vol 8 ◽  
Author(s):  
Ylva Nilsson
Keyword(s):  
Cast Iron ◽  
Laser Beam ◽  
Partial Melting ◽  
High Power ◽  
Surface Hardening ◽  
Beam Diameter ◽  
High Power Laser ◽  
Power Laser ◽  
Scanning Rate ◽  
Alloy Addition

ABSTRACTAn investigation is done on partial surface hardening and alloying on cast iron by means of a high power laser beam. Samples of cast iron have been covered with alloying material i.e. Ti, Cr, Si, V and Nb respectively. The samples were irradiated with a 2.5 kW laser beam. A partial melting of the surface occured and the alloys were dissolved. The carbide structure in the resolidified part was governed by the alloy addition. The carbide structure was metallographicly analysed. The effect of different parameters as beam diameter, scanning rate, power and alloy content have been investigated and the crack frequency has been evaluated.

scholarly journals Melt Stirring of Nodular Cast Iron

2018 ◽  
Vol 925 ◽  
pp. 125-132
Author(s):  
Fareed Ashraf Khan ◽  
Hasse Fredriksson
Keyword(s):  
Cast Iron ◽  
Nodular Cast Iron ◽  
Optical Microscope ◽  
Area Fraction ◽  
Distribution Area ◽  
Graphite Phase ◽  
Nodule Count ◽  
Nucleation Sites ◽  
Count Distribution ◽  
Scanning Electron

In this work the effects of stirring/vigorous shearing on matrix and graphite phase in nodular cast iron melt during solidification were studied. Several experiments were conducted for different cooling and stirring times. Samples were prepared and examinations of the microstructure were conducted and compared using Leica Optical Microscope and Scanning Electron Microscope (SEM). In addition, a chemical analysis of the graphite precipitate was performed using EDX equipment mounted on SEM. Oxidation of the melt and formation of oxide nuclei during stirring were observed and analysed. The influence of melt shearing on the structure, nodule count, distribution, area fraction and on overall graphite precipitation was observed and examined with the help of respective computer programs and soft wares. Stirring resulted in increasing the nucleation sites for graphite precipitation thereby increasing the nodule count and area fraction of carbide and transforming the structure from pearlitic matrix to ferritic matrix.

METASTABLE PHASES OBTAINED BY HIGH POWER LASER SURFACE MELTING OF CAST-IRON AND STEELS

1983 ◽  
Vol 44 (C5) ◽  
pp. C5-501-C5-505
Author(s):  
E. Ramous ◽  
L. Giordano ◽  
G. Principi ◽  
A. Tiziani
Keyword(s):  
Cast Iron ◽  
High Power ◽  
Surface Melting ◽  
Laser Surface ◽  
Metastable Phases ◽  
Laser Surface Melting ◽  
High Power Laser ◽  
Power Laser

scholarly journals Characterization of Coatings on Grey Cast Iron Fabricated by Hot-dipping in Pure Al, AlSi11 and AlTi5 Alloys

2014 ◽  
Vol 14 (1) ◽  
pp. 85-90 ◽  
Author(s):  
R. Mola ◽  
T. Bucki ◽  
K. Wcisło
Keyword(s):  
Cast Iron ◽  
Outer Layer ◽  
Intermetallic Layer ◽  
Optical Microscope ◽  
Pure Aluminium ◽  
Bath Composition ◽  
Graphite Cast Iron ◽  
Flake Graphite Cast Iron ◽  
Grey Cast

Abstract Flake graphite cast iron was hot-dip coated with pure aluminium or aluminium alloys (AlSi11 and AlTi5). The study aimed at determining the influence of bath composition on the thickness, microstructure and phase composition of the coatings. The analysis was conducted by means of an optical microscope and a scanning electron microscope with an EDS spectrometer. It was found that the overall thickness of a coating was greatly dependent on the chemical composition of a bath. The coatings consisted of an outer layer and an inner intermetallic layer, the latter with two zones and dispersed graphite. In all the cases considered, the zone in the inner intermetallic layer adjacent to the cast iron substrate contained the Al5Fe2 phase with small amount of silicon; the interface between this phase and the cast iron substrate differed substantially, depending on the bath composition. In the coatings produced by hot-dipping in pure aluminium the zone adjacent to the outer layer had a composition similar to that produced from an AlTi5 bath, the Al3Fe phase was identified in this zone. The Al3Fe also contained silicon but its amount was lower than that in the Al5Fe2. In the coatings produced by hot-dipping in AlSi11, the zone adjacent to the outer layer contained the Al3FeSi phase. The analysis results showed that when AlSi11 alloy was applied, the growth mode of the inner layer changed from inwards to outwards. The interface between the Al5Fe2 phase and the cast iron substrate was flat and the zone of this phase was very thin. Locally, there were deep penetrations of the Al5FeSi phase into the outer layer, and the interface between this phase and the outer layer was irregular. Immersion in an AlTi5 bath caused that the inner intermetallic layer was thicker than when pure aluminium or AlSi11 alloy baths were used; also, some porosity was observed in this layer; and finally, the interface between the inner layer and the cast iron substrate was the most irregular

scholarly journals Ultrasonic flaw detection spectrogram characterization of vermicular graphite cast iron engine cylinder head

2021 ◽  
Vol 1996 (1) ◽  
pp. 012005
Author(s):  
Changliang Guo ◽  
Duo Fang ◽  
Chengzong Wang ◽  
Tao Qin ◽  
Zenghua Liu ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Cast Iron ◽  
Wavelet Transform ◽  
Cylinder Head ◽  
Short Time Fourier Transform ◽  
Time Frequency ◽  
Graphite Cast Iron ◽  
Engine Cylinder ◽  
Empirical Wavelet Transform ◽  
Short Time

Abstract The defects formed in the manufacture of the vermicular graphite cast iron engine cylinder head seriously affect the operation of the engine, which is necessary to detect. Ultrasonic testing is a non-destructive testing method that has the advantages of quick response, high resolution, and high security. In this paper, various types of specimens are prepared corresponding to different types of actual defects in the vermicular iron cylinder head. An ultrasonic A-scan system was built to test the specimens. The short-time Fourier transform, the continuous wavelet transform, the empirical wavelet transform, and the empirical modal decomposition were adopted to transform the signals into spectrograms which were further analyzed to reveal the inherent features of defects. The results show that the short-time Fourier transform can be used to distinguish all the common defects comparing to other methods. Comparing to the time-domain waveforms, the transformed spectrograms provide clear time-frequency distribution and highlight the inherent characteristics of the signal.

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