Literature

MECHANICALLY ALLOYED (MA) SINTERED STEELS WITH A HIGH HARD PHASE CONTENT

F Thummler, C Gutsfeld, (University of Karlsruhe, Germany). Vol 2, Paper 6, 25-30.

Wear resistant sintered steels with hard insoluble inclusion are produced by MA and p r e s s u re l e s s l iqu id phase s in te r ing . Mechanical properties of a Fe- P-C steel with 10vol% of NbC, TiC, TiN or A1203 are compared. Effect of dispersed phase on structure, properties and wear resistance is discussed.

PRODUCTION OF AUTOMOTIVE CAMSHAFTS BY PM

G Greetham, T Chatterley, (Manganese Bronze Powder Metals Group, Ipswich, UK). Vol | , Paper 23,352-365.

Use of PM in manufacture of automotive camshafts as an alternative to cast iron is reviewed. The cam profiles are fitted to drawn steel tube and various locking designs are considered. (Steel tube: 0 .44-0.55%C, 0.35%Si, 0.5-0.9%Mn. PM cams: 44.5%Cr, 0.5 l%Cu, 0.64%Ni, 1.27%Si, 0.89%Mo, 0.56%P, 0.99%Mn, 0.014%C, Bal Fe.) Paper describes in situ sintering of cams on to the shaft.

INJECTION MOULDING MACHINE PARTS IN Mo2FeB2 COMPLEX BORIDE-BASE HARD ALLOYS

K-I Takagi, et al, (Toyo Kohan Ltd, Kudmatsu, Japan). Vol 1, Pater 25,374-384.

Effects of C on mechanical properties, structure and wear and corrosion resistance of Fe - 43%Mo-8 %Cr-2.5 %Ni-5 %B were investigated with reference to the ferrous binder. It was found that the matrix changes from ferritic to martensitic as the %C increases. It is stated that 0.1% residual C gives optimum combination of hardness and transverse rupture strength with a martensitic binder. Alloys have good wear resistance and good corrosion resistance conferred by Ni and Cr additions. It is suggested that injection moulding machine parts made in this alloy will have increased service life.

SURFACE PRESTRESSING FOR DENSIFICATION AND FATIGUE STRENGTH IMPROVEMENTS

D Tyler, (Metal Improvement Co, Deeside, UK). Vol 1, Paper 30, 415-418.

It is shown that shot-peening, applied to PM parts gives improvements in properties due to local ized densification, introduction of compressive stresses and structural changes. Examples are given of a wide range of applications. Process variables are considered.

MACHINING OF PM PARTS IN A FLEXIBLE MANUFACTURING ENVIRONMENT

G T Smith, (University of Birmingham, UK). Vol 1, Paper 36, 468-478.

The problems which may be encountered in the finish machining of PM parts in a flexible manufacturing cell are described. These must be overcome or minimized for satisfactory product quality, through use of statistical process control.

PLATING OF SINTERED Fe PARTS AND DIFFUSION ANNEALING OF COATINGS

R C Leu, L Alting, (Institute of Manufacturing Engineer ing , Technical Univers i ty of Denmark). Vol 1, Paper 37,479--487.

Attention is drawn to the difficulties in plating porous surfaces. The paper reviews techniques which may be used to prepare surfaces of Fe PM parts p r io r to e lec t ro- and electroless-plating. Cu, deposited from a cyanide electrolyte has a good effect on pore closure. Wear and corrosion resistant materials of mixed carbides were prepared, by diffusion annealing of a Cu deposit, and tested for wear and corrosion resistance. Diffusion annealing of Ni-Cr on to sintered Fe- 1%C gave best wear and corrosion resistance.

STEAM TREATMENT OF SINTERED PARTS

P Beiss , (S in te rmeta l lwerk-Krebsoge , Radevormwald, Germany). Vol 1, Paper 38, 488-496.

Thermodynamic and kinetic aspects of steam treatment of iron and steel are reviewed.

Examples are given of effect of density on mass gain and depth of penetration. Influence of steam oxidation on mechanical properties is illustrated.

PROCESSING AND PROPERTIES OF Fe-Bi-Sn BEARING ALLOY SYSTEMS

Y T Chen, (Pitney Bowes Inc, Stamford, USA). Vol 2, Paper 34, 184-195.

The use of Bi instead of Pb in low-cost s e l f - l ub r i ca t i ng bea r ings has been investigated. Effects of composition and processing variables on properties were investigated. An optimum composition was established as Fe-7.5%Bi-l%Sn. This alloy was compared with PM Cu-10%Sn. Results show that the Fe-base alloy is more satisfactory in mechanical properties and wear resistance and is easier to manufacture than the Cu alloy.

POWDER FORGING OF CYLINDRICAL GEARS WITH MULTI-PHASE STRUCTURE

M Weber, et al, (Sintermetallwerk - Krebsoge, Radevormwald, Germany). Vol 2, Paper 43, 246-250.

Powder forging has been used to produce cylindrical gears in HSS and Ni alloys. Structure, properties and tooth flank fatigue investigated.

ELECTROPLATING AS AN ANTI-CORROSION TREATMENT FOR PM PRECISION PARTS

H Danninger, et al, (Technical University, Vienna, Austria). Vol 2, Paper 63,343-347.

A study is repor ted of the effects of electroplating on the corrosion resistance (salt spray test) of PM parts. Adhesive strength of the electrodeposit was measured. The use of a primer, applied prior to electroplating, is reported.

APPLICATION OF CARBIDE STEEL COMPOSITES TO USE IN FUEL OIL BOILER ATOMIZERS

L Valdma, et al, (Technical University, Tallinn, Estonia, USSR). Vol 2, Paper 68,370-372.

The paper reports efforts to increase the service life of fuel atomizers in steam boilers by use of PM TiC composites. The Griffith-Orowan

792 MPR November 1990