- Email: [email protected]
Abrasive wear properties of sprayed tungsten carbide-cobalt coatings
Thermal spraying applications ABRASIVE WEAR PROPERTIES
depth of penetration structures. OF
SPRAYED TUNGSTEN CARBIDECOBALT COATINGS
M.Dorfman et al. (Sulzer Metco (US) Inc, USA.) High velocity oxy-fuel spraying of WC-(12 or 17)wt%Co deposits was described. Wear resistance was evaluated and correlated with structure. It was deduced that a high volume % of fine WC grains in the Co matrix is required for optimum wear resistance. Agglomerated powders were shown to yield coatings with 99% density and fine uniformly dispersed WC. The importance of avoiding decomposition of WC in the flame was emphasized.
and evaluate
the
FORMATION OF FREE GRAPHITE DURIN’G SINTERING OF IRON COMPACTS CONTAINING CARBON AND BORON S.Uenosono, K.Ogura. (Kawasaki Steel Carp, Japan.) Graphitization in Fe-1.4wt% graphite-B was investigated with the intention of improving machinability and sliding properties. The structure of the sintered steel was ferrite and 1% free graphite. Precipitated C could be distinguished from residual graphite. Formation of free graphite was attributed to precipitation during cooling.
Magnetic
materials
THERMAL SPRAYING OF MOLYBDENUM-NICKEL DIBORIDENICKEL CERMETS
MANUFACTURE OF ELECTROMAGNETIC BY PM
M.Sasaki et al. (Sulzer Metco (Japan) Ltd, Japan.) It was shown that Mo,NiB,-Ni cermets are superior to alloys such as WCCo and Tic-Ni. It was reported that Mo,NiB,-Ni had been deposited by spraying. Powders for spraying were prepared by milling, agglomerating and pseudo-sintering. The deposit had high density and good bonding to the substrate. Properties were compared with other cermets.
G.W.Ellis et al. (Hoeganaes Corp, Riverton, USA.) Materials and processes for production of electromagnetic parts by PM methods were discussed with regard to future growth and economics. Successful materials for AC and DC applications were reviewed.
Mechanisms diffusion
of carbon
CARBON PENETRATION AS A FUNCTION OF DENSITY AND CARBON POTENTIAL T.J.Krave. (Norton-Burgess Mfg Co, USA.) C diffusion into sintered steels at densities of 6.6-7.1 and 7.2-7.5 g.cmm3 was studied. The results were shown graphically and correlated with density and C potential. CARBON DIFFUSION IN ALLOY STEELS SUBJECTED TO GASEOUS AND PLASMA CARBURIZING F.deRege et al. (Domfer Metal Powders, Canada.) Carburizing of steels was discussed with regard to method. Liquid carburizing is not suitable for PM steels because of salt entrapment in pores. Earlier studies had shown the viability of various methods for PM low alloy and sinter-hardening steels. Studies of gas and plasma carburizing of C-free steels were described, the object being to establish suitable treatment cycles, to verify
COMPONENTS
HIGH DENSITY SOFT MAGNETIC COMPONENTS FOR AC AND DC APPLICATIONS H.R.Kokal et al. (Magnetics International Inc, USA.) It was reported that soft magnetic material parts, for AC uses, with high densities of 7.5-7.7 g.cme3 had been made by ambient temperature pressing of special powders at 850 MPa. For AC applications, insulated powders were used, which exhibited lower losses than laminated steels. For DC uses the powders were pressed and sintered. Physical characteristics and magnetic properties of parts were discussed.
Corrosion MMCs
and wear of
ABRASIVE WEAR OF PM TITANIUMMETAL MATRIX COMPOSITES
D.E.Alman et al. (Department of Energy, USA.) Abrasive wear of PM Ti metal matrix composites (MMCs) with 0,20 or 4Ovol% of TiB,, Tic, TiN, Sic or B,C particles was investigated. Specimens were made by hot-pressing at 1200°C and 20 MPa for 2 hours, except for Ti-TiB, which was pressed and sintered. Pin on drum tests with Sic or diamond abrasives were used. Wear resistance was correlated
with structure and properties of the composites and was compared with cast/wrought materials. HARDENABLE AUSTENITIC PM IRON BASE METAL MATRIX COMPOSITES M.O.Speidel et al. (Swiss Federal Inst. of Technology, Switzerland.) It was reported that a new class of MMC had been developed by use of a novel PM process. The matrix was a hardenable austenitic steel with high corrosion resistance, with nitride reinforcements. Properties could be changed by variation of nitride content and particle size which conferred hardness and wear resistance. Atomized or mechanically alloyed steel powders were nitrided and consolidated by HIP, or pressed and sintered and heat treated. DISTRIBUTION AND MORPHOLOGY OF LANTHANUM AND NEODYMIUM IN IRON-DIAMOND COMPOSITES Y.K.Wu, Y.Qing. (Yuzhou University, China.) Distribution and morphology of La and Nd in a sintered diamond-reinforced Fe matrix composite were investigated. La and Nd were shown to adsorb on the diamond/Fe interface during liquid phase sintering. Good adhesion between Fe and diamond was attributed to the segregated La and Nd and resulted in improved properties.
Surface treatments SURFACE ENGINEERING OF A MOLYBDENUM STEEL BY NITROGEN, OXYGEN AND SULPHUR J.Kazior et al. (Cracow University of Technology, Cracow, Poland.) Experiences of gas nitriding of a 1.5%Mo steel were described. By variations in process conditions it was possible to introduce N, 0 and S to form a layered surface structure. B was added to reduce case depth and increase hardness by formation of BN. Structure and properties of the hardened layers were characterized and wear properties investigated. NITROCARBURIZATION OF PM MATERIALS FOR IMPROVED MECHANICAL AND TRD3OLOGICAL PROPERTIES P.Kjeldsteen. (Danfoss AS, Denmark.) Experiments to determine the effects of nitrocarburizing of steel on mechanical and tribological properties were described. Mechanical properties and fatigue were correlated with pre-treatments. The importance of surface topography for wear properties was emphasized.
MPR May 1998 41
depth of penetration structures. OF
SPRAYED TUNGSTEN CARBIDECOBALT COATINGS
M.Dorfman et al. (Sulzer Metco (US) Inc, USA.) High velocity oxy-fuel spraying of WC-(12 or 17)wt%Co deposits was described. Wear resistance was evaluated and correlated with structure. It was deduced that a high volume % of fine WC grains in the Co matrix is required for optimum wear resistance. Agglomerated powders were shown to yield coatings with 99% density and fine uniformly dispersed WC. The importance of avoiding decomposition of WC in the flame was emphasized.
and evaluate
the
FORMATION OF FREE GRAPHITE DURIN’G SINTERING OF IRON COMPACTS CONTAINING CARBON AND BORON S.Uenosono, K.Ogura. (Kawasaki Steel Carp, Japan.) Graphitization in Fe-1.4wt% graphite-B was investigated with the intention of improving machinability and sliding properties. The structure of the sintered steel was ferrite and 1% free graphite. Precipitated C could be distinguished from residual graphite. Formation of free graphite was attributed to precipitation during cooling.
Magnetic
materials
THERMAL SPRAYING OF MOLYBDENUM-NICKEL DIBORIDENICKEL CERMETS
MANUFACTURE OF ELECTROMAGNETIC BY PM
M.Sasaki et al. (Sulzer Metco (Japan) Ltd, Japan.) It was shown that Mo,NiB,-Ni cermets are superior to alloys such as WCCo and Tic-Ni. It was reported that Mo,NiB,-Ni had been deposited by spraying. Powders for spraying were prepared by milling, agglomerating and pseudo-sintering. The deposit had high density and good bonding to the substrate. Properties were compared with other cermets.
G.W.Ellis et al. (Hoeganaes Corp, Riverton, USA.) Materials and processes for production of electromagnetic parts by PM methods were discussed with regard to future growth and economics. Successful materials for AC and DC applications were reviewed.
Mechanisms diffusion
of carbon
CARBON PENETRATION AS A FUNCTION OF DENSITY AND CARBON POTENTIAL T.J.Krave. (Norton-Burgess Mfg Co, USA.) C diffusion into sintered steels at densities of 6.6-7.1 and 7.2-7.5 g.cmm3 was studied. The results were shown graphically and correlated with density and C potential. CARBON DIFFUSION IN ALLOY STEELS SUBJECTED TO GASEOUS AND PLASMA CARBURIZING F.deRege et al. (Domfer Metal Powders, Canada.) Carburizing of steels was discussed with regard to method. Liquid carburizing is not suitable for PM steels because of salt entrapment in pores. Earlier studies had shown the viability of various methods for PM low alloy and sinter-hardening steels. Studies of gas and plasma carburizing of C-free steels were described, the object being to establish suitable treatment cycles, to verify
COMPONENTS
HIGH DENSITY SOFT MAGNETIC COMPONENTS FOR AC AND DC APPLICATIONS H.R.Kokal et al. (Magnetics International Inc, USA.) It was reported that soft magnetic material parts, for AC uses, with high densities of 7.5-7.7 g.cme3 had been made by ambient temperature pressing of special powders at 850 MPa. For AC applications, insulated powders were used, which exhibited lower losses than laminated steels. For DC uses the powders were pressed and sintered. Physical characteristics and magnetic properties of parts were discussed.
Corrosion MMCs
and wear of
ABRASIVE WEAR OF PM TITANIUMMETAL MATRIX COMPOSITES
D.E.Alman et al. (Department of Energy, USA.) Abrasive wear of PM Ti metal matrix composites (MMCs) with 0,20 or 4Ovol% of TiB,, Tic, TiN, Sic or B,C particles was investigated. Specimens were made by hot-pressing at 1200°C and 20 MPa for 2 hours, except for Ti-TiB, which was pressed and sintered. Pin on drum tests with Sic or diamond abrasives were used. Wear resistance was correlated
with structure and properties of the composites and was compared with cast/wrought materials. HARDENABLE AUSTENITIC PM IRON BASE METAL MATRIX COMPOSITES M.O.Speidel et al. (Swiss Federal Inst. of Technology, Switzerland.) It was reported that a new class of MMC had been developed by use of a novel PM process. The matrix was a hardenable austenitic steel with high corrosion resistance, with nitride reinforcements. Properties could be changed by variation of nitride content and particle size which conferred hardness and wear resistance. Atomized or mechanically alloyed steel powders were nitrided and consolidated by HIP, or pressed and sintered and heat treated. DISTRIBUTION AND MORPHOLOGY OF LANTHANUM AND NEODYMIUM IN IRON-DIAMOND COMPOSITES Y.K.Wu, Y.Qing. (Yuzhou University, China.) Distribution and morphology of La and Nd in a sintered diamond-reinforced Fe matrix composite were investigated. La and Nd were shown to adsorb on the diamond/Fe interface during liquid phase sintering. Good adhesion between Fe and diamond was attributed to the segregated La and Nd and resulted in improved properties.
Surface treatments SURFACE ENGINEERING OF A MOLYBDENUM STEEL BY NITROGEN, OXYGEN AND SULPHUR J.Kazior et al. (Cracow University of Technology, Cracow, Poland.) Experiences of gas nitriding of a 1.5%Mo steel were described. By variations in process conditions it was possible to introduce N, 0 and S to form a layered surface structure. B was added to reduce case depth and increase hardness by formation of BN. Structure and properties of the hardened layers were characterized and wear properties investigated. NITROCARBURIZATION OF PM MATERIALS FOR IMPROVED MECHANICAL AND TRD3OLOGICAL PROPERTIES P.Kjeldsteen. (Danfoss AS, Denmark.) Experiments to determine the effects of nitrocarburizing of steel on mechanical and tribological properties were described. Mechanical properties and fatigue were correlated with pre-treatments. The importance of surface topography for wear properties was emphasized.
MPR May 1998 41