LASER CLADDING OF LOW ALLOY STEEL SUBSTRATES WITH CARBON-FREE TOOL STEELS Fe-Co-Mo/W

Cladding by laser deposition is an effective way to modify metallic surfaces, e.g. to improve the hardness and wear resistance. In the present work, carbon-free tool steel layers of the general composition Fe-Co-Mo(-W) were produced on structural steel surfaces by laser depositing gas atomized spher...

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Bibliographic Details
Published in:Powder Metallurgy Progress 2013-01, Vol.13 (1), p.11-21
Main Authors: Garcia, L F, Danninger, H, Ponemayr, H
Format: Article
Language:English
Subjects:
Atomizing
Deposition
Hardness
Laser deposition
Lasers
Steels
Structural steels
Tool steels
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Summary:Cladding by laser deposition is an effective way to modify metallic surfaces, e.g. to improve the hardness and wear resistance. In the present work, carbon-free tool steel layers of the general composition Fe-Co-Mo(-W) were produced on structural steel surfaces by laser depositing gas atomized spherical powders. In a preliminary test series, a large variety of different compositions were prepared by pressing, sintering and laser remelting and tested with regard to their hardening behaviour. From two promising grades, prealloyed powders were manufactured by gas atomizing and deposited on Cr alloy structural steel, a CO sub(2) laser being used. Then the layers were heat treated by aging at different temperatures. It showed that these precipitation-hardenable tool steel grades are particularly well suited for laser deposition since they are fairly soft and ductile as-deposited, thus avoiding the cracking problems common with standard carbidic tool steels, which exhibit a brittle ledeburitic microstructure after laser deposition, and also enable soft machining. After a subsequent isothermal aging process at about 600[degrees]C, a full hardness of about 65 HRC is obtained, the isothermal treatment resulting in virtually distortion-free hardening.
ISSN:1335-8987