Study of the process parameters influence on crack formation in laser alloying of grey cast iron

• This study aimed to investigate the influence of process parameters on crack formation in laser alloying or cladding of grey cast iron. For this purpose, the effects of laser power and feeding rate of Ni-based alloying powders were examined. The microstructure and hardness of the coating and the interface of the coating with cast iron (bonding zone) were studied. The results showed that the dilution ratio is crucial in crack formation, explaining the challenges in achieving a defect-free laser alloying coating on cast iron. The higher dilution ratio of laser alloying resulted in higher dissolved carbon and bigger (Nb, Ti)C carbides formation than in laser cladding coatings. In this study, cracks appeared in the coating due to the combination of the high amount of carbide in the layer and a sharp hardness gradient at the interface with the cast iron substrate. An empirical relation was proposed for dilution ratio as a function of specific energy density, which combined the most critical process parameters on crack formation.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Nyckelord

Cracks

Grey cast iron

Laser alloying

Laser cladding

Microstructure

Ni alloy

Alloying

Carbides

Cast iron

Coatings

Hardness

Nickel alloys

Titanium compounds

Dilution ratio

Feeding rate

Gray cast iron

Influence of process parameters

Laser power

Ni alloys

Parameter influences

Power rates

Process parameters

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)