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

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.

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Laser surface melting of the cast iron SCH20 after chill casting

Metal Working and Material Science ◽

10.17212/1994-6309-2017-1-40-50 ◽

2017 ◽

pp. 40-50

Author(s):

Viktor Gilev ◽

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Evgenii Morozov ◽

Ivan Purtov ◽

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...

Keyword(s):

Cast Iron ◽

Surface Melting ◽

Laser Surface ◽

Laser Surface Melting ◽

Chill Casting

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Direct Diode Laser Surface Melting of Nodular Cast Iron

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.809-810.423 ◽

2015 ◽

Vol 809-810 ◽

pp. 423-428 ◽

Cited By ~ 5

Author(s):

Damian Janicki

Keyword(s):

Cast Iron ◽

Diode Laser ◽

Heat Input ◽

Volume Fraction ◽

Residual Austenite ◽

Nodular Cast Iron ◽

Surface Melting ◽

Laser Surface ◽

Test Method ◽

Laser Surface Melting

A nodular cast iron (NCI) has been surface melted using the high power direct diode laser (HPDDL) with a quasi-rectangular laser beam spot and the uniform distribution of power. The effect of a heat input and a shielding gas on the quality of surface melted layers (SMLs) has been investigated. The microstructure of the SMLs has been assessed by optical microscopy, scanning electron microscopy and X-ray diffraction (XRD). Comparative erosion tests between the SMLs and as-received NCI have been performed following the ASTM G 76 standard test method. The HPDD laser surface melting of the NCI enables to produce non-porous layers having a hardness up to 1000 HV. It has been determined that the hardness of SMLs depends on the amount of cementite and residual austenite in the fusion zone. The SMLs produced in an argon atmosphere contain higher volume fraction of austenite, than those produced in nitrogen, and consequently have the lower hardness. With increasing heat input the hardness increases, as the result of more complete dissolution of graphite and the higher amount of cementite. The SMLs exhibited significantly higher erosion resistance than the as-received NCI for erodent impact angle of 3<em>0°, and slightly lower at 90°.</em><em></em>

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Microstructural characteristics of cobalt treated by high-speed laser surface melting under high power

Materials Characterization ◽

10.1016/j.matchar.2017.03.037 ◽

2017 ◽

Vol 128 ◽

pp. 63-67 ◽

Cited By ~ 5

Author(s):

Jian Tu ◽

Kun-Feng Zhou ◽

Zhi-Ming Zhou ◽

Can Huang ◽

Hai-Long Tang

Keyword(s):

High Power ◽

High Speed ◽

Surface Melting ◽

Laser Surface ◽

Laser Surface Melting ◽

Microstructural Characteristics

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Laser Surface Melting of a Pearlitic Grey Cast Iron

Rapidly Quenched Metals 6 ◽

10.1016/b978-1-85166-972-1.50064-6 ◽

1988 ◽

pp. 305-308

Author(s):

F. FOUQUET ◽

E. SZMATULA

Keyword(s):

Cast Iron ◽

Surface Melting ◽

Laser Surface ◽

Grey Cast Iron ◽

Laser Surface Melting ◽

Grey Cast

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.456.474 ◽

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.

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