Sandvik Ab

E Torbjorn Hartzell

Udo K Fischer

Jan G Akerman

The present invention relates to cemented carbide bodies preferably for rock drilling and mineral cutting. Due to the fact that the bodies are built up of a core of eta-phase-containing cemented carbide surrounded by a surface zone free of eta-phase with low Co-content in the surface zone and successively increasing Co-content to a maximum in the outer part of the eta-phase-core they have obtained an increase in toughness and life at practical use.

Cemented carbide body with extra tough behavior

A cemented carbide button for rock drilling comprises a core and a surface zone surrounding the core whereby both the surface zone and the core contains WC (alpha-phase) and a binder phase based on at least one of Co, Ni, or Fe and the core in addition contains eta-phase. The eta-phase core extends to the very top (working) surface of the button and as a result is obtained longer life and higher drilling rate particularly for rotating crushing drilling, cutting drilling and percussive drilling in soft rocks.

Cemented carbide body with increased wear resistance

The present invention relates to cemented carbide bodies preferably for wear demanding rock drilling and mineral cutting. The bodies are built up of a core of eta-phase-containing cemented carbide surrounded by a surface zone free of eta-phase where the binder phase content in the outer pan of said zone is lower than the nominal and, in addition, constant or near constant, and the binder phase content in the inner part of the eta-phase free zone closer to the eta-phase core is higher than the nominal. According to the method of the invention, bodies comprising evenly distributed eta-phase are subjected to a partly carburizing treatment with a carbon activity, a.sub.c, close to 1.

Cemented carbide body used preferably for abrasive rock drilling and

The present invention relates to cemented carbide bodies preferably for wear demanding rock drilling and mineral cutting. The bodies are built up of a core of eta-phase-containing cemented carbide surrounded by a surface zone free of eta-phase where the binder phase content in the outer part of said zone is lower than the nominal and, in addition, constant or near constant, and the binder phase content in the inner part of the eta-phase free zone closer to the eta-phase core is higher than the nominal. According to the method of the invention, bodies comprising evenly distributed eta-phase are subjected to a partly carburizing treatment with a carbon activity, a.sub.c, close to 1.

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Stockholm, Sweden

E Torbjorn Hartzell