Abstract: A metallic drilling member is surface hardened except at an end portion, because the end portion is masked. The masking is achieved by placing on the end portion a lid which forms a slight gap around the surface being heat treated. During the heat treatment a furnace atmosphere enters the gap to cause the depth of the heat treatment to be gradually decreased in a manner producing a relatively elongated transition zone between heat treated and non-heat treated portions of the surface. The gap can be of constant width, or gradually decreasing width.

Abstract: A method for making artificial tooth bridges having a ceramic densely sintered high strength individual core veneered with porcelain using powder metallurgical methods, wherein the individual bridge parts are joined together as a bridge core with glass, which in molten condition wets the ceramic core material. The glass therefore finds its way into the gap between the bridge parts and reacts with the ceramics so that during cooling it forms a strong joint between the individual densely sintered ceramic bridge parts.

Abstract: A dispersion hardened FeCrAl-alloy and method of its production which includes in one step, forming a nitride dispersion in a FeCr-alloy, whereby this nitride dispersion includes one or more of the basic elements hafnium, titanium and zirconium, and, in a later step aluminum is added to the nitrided FeCr-alloy. The unfavorable formation of aluminum nitrides has thereby been avoided by adding aluminum after the nitriding. A FeCrAl-alloy with high high temperature strength and high creep strength has thereby been achieved.

Abstract: The present invention relates to a method of making a WC—Co-based cemented carbide with a sintered mean WC-grain size in the range 0.4-1.6 &mgr;m. the cemented carbide is produced from well deagglomerated or easy to deagglomerate WC powder with round morphology, a Co powder also well deagglomerated or easy to deagglomerate and with a grain size equal to or smaller than the WC grain size and grain growth inhibitors. According to the invention the metal part of the grain growth inhibitors is added as part of the binder phase i.e., is included in the Co powder and alloyed therewith.

Abstract: The present invention discloses an HSS tool with a PVD coating and with at least one cutting edge. The cutting edge has a radius of 15-25 &mgr;m and the carbides in the HSS are in contact with the coating. The present invention also relates to a method of making an HSS tool provided with a PVD coating with improved wear resistance. The improvement is obtained by subjecting the tool prior to the deposition of the coating to an electropolishing treatment such that a cutting edge radius of 15-25 &mgr;m is obtained and that the carbides in the HSS are revealed.

Abstract: There is disclosed a cemented carbide insert with excellent properties for machining of steels and stainless steels. The cemented carbide comprises WC and 4-25 wt-% Co. The WC-grains have an average grain size in the range 0.2-3.5 &mgr;m and a narrow grain size distribution in the range 0-4.5 &mgr;m. According to the method of the invention a cemented carbide cutting tool insert is made by mixing powders of WC, TiC, TaC and/or NbC, binder metal and pressing agent, drying preferably by spray drying, pressing to inserts and sintering. The method characterised in that a deagglomerated WC-powder with a narrow grain size distribution is used, that the powders of TiC, TaC and/or NbC are deagglomerated and that the mixing is wet mixing with no change in grain size or grain size distribution.

Abstract: A drill bit has a plurality of cemented carbide buttons embedded in a front end of the drill body. Each button includes a cemented carbide body having a rear mounting portion embedded in the drill body, and a symmetrically shaped crushing end protruding from the drill body. The buttons are oriented at a first acute angle of from about 35° to about 55° relative to the rotational center axis of the drill bit. The crushing end of the button includes at least one annular groove defining axially spaced local maximum points at each side of the groove. An imaginary line touching the maximum points defining a second acute angle relative to the center line of the button. The second angle is smaller than the first acute angle.

Abstract: According to the present invention there is now provided a body of cemented carbide or cermets coated with at least one diamond layer. The diamond layer is smooth on all sides of the body with an Ra<1 &mgr;m. According to the present invention there is also provided a method for reactive ion etching of a diamond layer on a complex shape body where the etching is efficient at all sides of the body exposed to the plasma. The etching is made using a C— or oxygen-containing plasma with the possibility of etching of a diamond layer covered by an outer layer of preferably a Si containing material.

Abstract: The present invention relates to a method of making a cemented carbide comprising WC, 6-12 wt. % Co and 0.1-0.7 wt. % Cr, wherein the WC-grains are coated with Cr prior to mixing and no milling takes place during the mixing step. As a result a cemented carbide with improved properties is obtained.

Abstract: As there is disclosed a cemented carbide body comprising WC with an average grain size of <10 &mgr;m in a binder phase. In the cemented carbide body the WC grains can be classified in at least two groups in which a group of smaller grains has a maximum grain size amax and a group of larger grains has a minimum grain size bmin and each group contains at least 10 % of the total amount of WC grains. According to the invention bmin−amax>0.5 &mgr;m and the difference in grain size within each group is >1 &mgr;m.

Abstract: The present invention describes a coated cutting tool for metal machining. The coating is formed by one or more layers of a refractory compound of which at least one layer of fine-grained, crystalline &ggr;-phase alumina, Al2O3, with a grain size of less than 0.1 &mgr;m. The Al2O3 layer is deposited with a bipolar pulsed DMS technique (Dual Magnetron Sputtering) at substrate temperatures in the range 450° C. to 700° C., preferably 550° C. to 650° C., depending on the particular material of the tool body to be coated. Identification of the &ggr;-phase alumina is made by X-ray diffraction. Reflexes from the (400) and (440) planes occurring at the 2&thgr;-angles 45.8 and 66.8 degrees when using Cu&kgr;&agr; radiation identify the &ggr;-phase Al2O3. The alumina layer is also very strongly textured in the [(440)]-direction. The Al2O3 layer is virtually free of cracks and halogen impurities. Furthermore, the Al2O3 layer gives the cutting edge of the tool an extremely smooth surface finish.

Abstract: In an air actuated down-the-hole hammer for rock drilling, a piston reciprocates within a casing to impact against a rear anvil surface of a drill bit. Upon making such impact, some fluid disposed between the impact surface and the anvil surface is forced radially inwardly toward a foot valve which fluidly inner connects central passages extending through the piston and the drill bit. In order to minimize the wear of the foot valve imposed by such forced fluid, either the piston or the drill bit includes a projection extending around a radially inner peripheral edge thereof for deflecting the forced fluid in a direction having an axial component to minimize an impact force of the fluid against the foot valve.

Abstract: A method of sintering cemented carbide bodies includes heating said bodies to the sintering temperature in a suitable atmosphere and cooling. If said cooling at least to below 1250° C. is performed in a higher speed i.e. at more than 20° C./min cemented carbide bodies with no surface layer of binder phase are obtained. This is an advantage when said bodies are to be coated with wear resistant layers by the use of CVD-, MTCVD- or PVD-technique.

Abstract: A rock drilling tool includes a pilot bit screw threaded into a front end of a drill rod. A reamer is mounted on the outside of the pilot bit. The reamer includes a central opening having a front portion and a rear portion. The front portion is connected to the pilot bit, and the rear portion constitutes a stiffening sleeve which extends around the outside of the drill rod.

Abstract: A twist drill includes a shank which defines a longitudinal center axis and has a helical, chip-transporting flute formed therein. A cutting insert is arranged at a front end of the flute. The insert includes a body forming a cutting edge and a flank surface arrangement situated behind the cutting edge. The flank surface arrangement includes first and second flank surfaces extending at respective first and second acute angles relative to a reference plane which contains the center axis. The sizes of the first and second acute angles are different from one another. In one embodiment, each of the first and second flank surfaces intersects the cutting edge. In a second embodiment, only the second flank surface intersects the cutting edge, with the first flank surface extending from a rear end of the second flank surface.

Abstract: A coated turning insert particularly useful for turning in stainless steel is disclosed. The insert is characterized by a WC—Co-based cemented carbide substrate having a highly W-alloyed Co-binder phase and a coating including an inner layer of TiCxNyOz with columnar grains followed by a layer of fine-grained &kgr;-Al2O3 and a top layer of TiN. The layers are deposited by using CVD-methods.

Abstract: A rock drilling rig includes a movable carrier with a boom attached to it and movable in various ways. The free end of the boom is provided with drilling equipment. The drilling equipment is enclosed in a casing that prevents noise generated during drilling from spreading to the surroundings. The casing is arranged to move together with a feed beam and relative to the cradle mounted on the end of the boom. A flexible noise attenuating skirt projects forwardly from a front end of the casing for forming a sealed chamber around a drilling head.

Abstract: The present invention relates to a method for obtaining a sintered body of carbonitride alloy with titanium as main component which does not have a binder phase layer on the surface after sintering. This is obtained by performing the liquid phase sintering step of the process at 1-80 mbar of CO gas in the sintering atmosphere.

Abstract: The invention provides a method for the continuous manufacture of ferritic stainless steel bands suitable for use in environments with frequent changes in temperature. It has been found preferable to have such band longitudinally displaced through a coating chamber wherein the band is provided with a coating of aluminum that is deposited thereon by means of physical vapor deposition technology during a time period sufficient so that aluminum becomes evenly distributed in the ferrite, after which a homogenization occurs at 950-1150° C.