Quenching of Ceramic Coated Steels by Scanning Laser

In our previous study, it has been shown that improvement of the adhesive strength and substrate hardness of ceramic coated steels without compromising the film hardness can be achieved by applying laser quenching. In the present research, in order to quench a larger area of ceramic coated steel uniformly and efficiently, a high power diode laser equipped with a galvano-scanner unit was used in the laser heat treatment process. The scanning laser irradiation conditions to achieve uniformly quenched substrates without any surface damage were investigated for 3 kinds of ceramic-coated steels: CrAlN, TiAlN and CrN. The film hardness and adhesive strength of the laser irradiated regions were evaluated. It is shown that scanning laser quenching after coating effectively improved the mechanical properties for larger area of ceramic-coated steels.

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Strengthening of Ceramic Coated Steel by Laser Quenching

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.157-158.175 ◽

2012 ◽

Vol 157-158 ◽

pp. 175-180 ◽

Cited By ~ 5

Author(s):

Hirotaka Tanabe ◽

Keiji Ogawa ◽

Takuya Saraie ◽

Mitsuhiro Gotoh ◽

Hideki Hagino ◽

...

Keyword(s):

Laser Irradiation ◽

Adhesive Strength ◽

High Heat ◽

Coated Specimen ◽

Heat Absorption ◽

Coated Steel ◽

Laser Quenching ◽

Film Hardness ◽

The Difference ◽

Substrate Hardness

In order to investigate the effectiveness of laser quenching for ceramic coated steels, 2 kinds of ceramic coated specimens of CrAlN and TiAlN were prepared, and the laser quenching experiments under various irradiation conditions were carried out. The influence of laser irradiation on the substrate hardness, film hardness and adhesive strength were investigated. Because of the high heat absorption of CrAlN and TiAlN films when compared to TiN, it was possible to quench the substrate effectively without any absorbent material for these specimens, although an absorbent was required for TiN coated specimen. The quenched area on the cross section of the substrate of CrAlN coated specimen was larger than that of TiAlN coated specimen. The difference of the quenched area could be explained by the difference of the heat absorption of these films. It was also possible to improve the adhesive strength of these films by laser irradiation. Although the film hardness decreased considerably by furnace quenching for ceramic coated steels, film hardness did not decrease by laser irradiation. It was concluded that the improvement of the adhesive strength and substrate hardness without the decrease of film hardness was achieved by laser quenching for CrAlN and TiAlN coated specimens.

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Influence of Laser Heat Treatment on Fracture Strength of Ceramic Thin Film

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.566.145 ◽

2012 ◽

Vol 566 ◽

pp. 145-149

Author(s):

Hirotaka Tanabe ◽

Keiji Ogawa ◽

Yui Izumi ◽

Tohru Takamatsu ◽

Heisaburo Nakagawa ◽

...

Keyword(s):

Thin Films ◽

Heat Treatment ◽

Fracture Strength ◽

Strength Loss ◽

Substrate Material ◽

Laser Quenching ◽

Ceramic Thin Films ◽

Film Hardness ◽

Induced Changes ◽

Substrate Hardness

In our previous study, it has been shown that improvement of the adhesive strength and substrate hardness of ceramic coated steels without compromising the film hardness can be achieved by applying laser quenching. In the present research, in order to demonstrate further development of this method, the fracture strength of laser-irradiated ceramic thin films (CrAlN, TiAlN and CrN) was investigated by sphere indentation testing. To prevent heat-induced changes in the substrate hardness, a cemented carbide WC-Co rather than steel was used as substrate material. While the fracture strength of each film decreased significantly through furnace heat treatment, it remained almost unchanged in case of the laser irradiated films. Laser quenching has been shown to effectively reduce the fracture strength loss of the ceramic thin films in coated steels.

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