Effect of process conditions on ion nitrided sintered iron-molybdenum alloys

Effect of process conditions on ion nitrided sintered iron-molybdenum alloys

Production and properties of sintered alloys were discussed with reference to formation of intermetallic compounds and precipitation hardening. It was...

167KB Sizes 1 Downloads 11 Views

Production and properties of sintered alloys were discussed with reference to formation of intermetallic compounds and precipitation hardening. It was considered that high energy ball milling was the best way of preparing homogeneous alloy powder followed by reactive sintering, extrusion and heat treatment. A Cu4wtXTi alloy was shown to have a strength of 900 MPa with 15% elongation and good electrical conductivity. Addition of graphite to form TIC was considered.

speed steels

High

Applications of metal fibres and fabrication by PM techniques were discussed. Fibres as small as 1 pm in diameter can be used in conjunction with other metals, powdered or molten, ceramics or polymers to make filter media, conductive plastics, toughened ceramics etc with a wide range of properties.

OF

PHYSICAL

Bolton,

A.J.

Gant.

(University

of

TiC enhanced the replacement of M& carbides by MC only in the presence of V. NbC formed MC carbides but did not encourage the replacement of M&. A complex carbo-sulphide phase formed between Tic and MnS.

Kunze

et

al

(Academy

of

Mining

and

and FeB were described. Cu coated M2 powder were blended with FeB and cold pressed and vacuum graphite, sintered. The objectives were the attainment of near net shape and good wear properties. Variations in composition and process conditions were studied.

Porosity and porous materials PRODUCTION

OF HIGHLY

MATERIALS

AND PARTS

et

al

POROUS BY POWDER

Research,

Inst. for Applied

Materials Research, Bremen, Germany) The ability of PM to produce highly porous parts was discussed with reference to the needs of transport industries for light weight materials which may be met by hollow sphere structures and metallic foams. New technology was said to be needed for processing fibres into, for example,

hot

gas filters

and for catalytic

EFFECT OF PROCESS CONDITIONS ION NITRIDED SINTERED IRONMOLYBDENUM ALLOYS

for Ger-

Predicted

and

that a new PM technique

measured

of of

said to be presented.

values

were

compared. POREAUX

ARMES

CARACTERISTIQUES

ET

TECHNOLOGIQUES L. Brndusan.

(University

The

properties

were

shown

to

of the wire used

support and on the wires. Strength

the spacing decreased as

increased.

good

of different

CONTINUOUS SINTERED

STEAM

TREATMENT

IMPROVED

WITH

et

al

(University

and

continuous

compared

for

(Don

State

Technical

University, Rostow-on-Don, Russia) Experiences in the production

of thin in in

machinery, were discussed. for rapid densification were

outlined. The technique was shown to have advantage over extrusion in not a binder.

different

Porosities

powders

were

microstructural

characteristics.

in the oxidised

EFFECT

and

Continuously to have was not

layer. Continuous

OF SINTERING

ON FATIGUE

CONDITIONS

OF DIFFUSION

ALLOYED

STEEL K-H. Lindner,

C.M. Sonsino.

(F’raunhofer

Germany) properties,

or

1250°C

were investigated. and temperature

wall PM tubes, with a density gradient the radial direction, for use as filters hydraulic Schemes

steam treated by proceedures,

processing was shown to be cheaper. Quality control methods were outlined.

1120 et al

of Trento,

fatigue

and

fracture, of a diffusion alloyed 4%Ni1.5%Cu-0.5%Mo-0.6%C steel, sintered at

PENETRABILITY

K.K. Shugay

fracture

and

for

30 or

120 minutes,

Increased

sintering

were reported

fatigue

properties

due

was considered to be industrial mass production. 1250°C was recommended of stressed

too long for 30 minutes at for manufacture

parts.

obtained

were determined.

were described.

INFLUENCE

OF SINGULAR

ON FATIGUE SINTERED

Steels

D. Spoljaric

et

Vienna, Austria) The effect of

LAYER ON SINTERED

fatigue

properties

treated

OF

LOW ALLOY STEELS

EFFECT OF SILICON MANGANESE AND NICKEL ON PLASMA NITRIDED STEELS

DEFECTS

PROPERTIES

al

(Technical

spherical of

pores

sintered

1.5%Mo-0.6%C with

University,

regard

on

and steel

was

Floriano-

investigated

polis, Brazil) It was reported

nitriding

transient liquid phase sintering. The fatigue

and the size of secondary that

plasma

to total

porosity

pores induced

strength for up to 2x10s cycles at R=-1 the threshold

FIBRE

(N.V.Bekaert

S.A. Zwevegem,

Belgium)

36

MPR

was found to increase nitrided

1995

the hardness

layer and N penetration

boundaries.

September

the heat

A.N. Klein et al (LABMAT/UFSC,

Ni steels in order to determine the effect of each element on nitride layer formation. Si

R. de Bruyne.

to

better microstructural homogeneity and improved pore shape. 120 minutes

had been carried out on sintered Si, Mn and REVISITED

time

to improve

applications. METALLURGY

OF

IRON PARTS

A. Molinari

detected

was

for the steels

density.

Inst. Darmstadt,

OIL FILTERES

nitriding

but with differences

Mechanical IRON BASED

needing

of CH4 was described.

that

treated materials were reported better quality and ferric oxide

de Cluj-Napoca,

on the diameter

spacing

reported

structural

Cluj-Napoca, Romania) (In French). It was reported that a reinforced porous

for the between

It was

batch

MECANIQUES

ON

of Genoa, Genoa,

Trento, Italy) Sintered Fe specimens,

SYSTEMES

depend

with small amounts attained

Service performances (Fraunhofer

Inst.

Bremen,

20% or less. Structures were cellular. Property data was

using

METALLURGY H.D. Kunze.

OF METALLIC

(Fraunhofer

Materials

vibration.

Metallurgy, Krakow, Poland) Investigation to optimise processing of M2 high speed steels with additions of Cu

zone.

Italy) An investigation of ion nitriding, at 59O”C, of Fe-l.S%Mo at densities of 7.0 and 7.5gm.cme3 and different N:H ratios

material had been obtained by sintering a spherical powder on a square cell metallic textured support and using intermittent

OPTIMIZATION OF LIQUID PHASE SINTERING OF M2 HIGH SPEED STEELS WITH BORON AND COPPER Cias

AND

had been developed for the production metallic foams with relative densities

Bradford, Bradford, UK) It was reported that HSS matrix composites with TiC or NbC particles and MnS had been sintered to full density. Microstructural changes were described.

A.

PROPERTIES

many) It was reported

CERAMIC AND SOLID LUBRICANT PARTICLES IN HIGH SPEED STEELS J.D.

MECHANICAL

FOAMS H.D.

AND STABILITY

and promoted of the diffusion

E. Stagno et al (University SELECTED

Applied REACTIONS

increased hardness homogeneous hardening

Ni

reduced

of the

at grain

hardness.

Mn

stress intensimty

by and

for fatigue

crack growth were determined. A Kitagawa diagram was used to predict tolerable defect

sizes and to estimate

as a function

of pore size.

fatigue

limit