Corrosion and mechanical properties of stainless steels

Corrosion and mechanical properties of stainless steels

parameters and particle size distribution and microstructures were investigated for two Ni base alloys. Design of experiments concepts were used in an...

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parameters and particle size distribution and microstructures were investigated for two Ni base alloys. Design of experiments concepts were used in an industrial setting. The most important parameters for particle

size distribution

gas pressure, alloy atomizer geometry.

were found to be composition

and

matrix, such as oxides or introduced by mechanical was investigated.

carbides, alloying,

A perspective powders

on metal

SOME

USES OF METAL

SURPRISING

A die lubrication PM parts production or die are heated,

FROM

OF ALUMINIUM

MECHANICALLY

ALLOY

ALLOYED

Unusual

and et al. (Polytechnic

University

of Madrid, Madrid, Spain. ) It was reported that a 2014 Al alloy powder had been prepared from elemental powders by mechanical alloying followed by extrusion at 500°C. with an extrusion ratio of 25:1, and heat treatment to optimize properties and structure. Powders and consolidated alloy were characterized and a high degree of homogeneity was reported. PRODUCTIVE

MECHANICAL

BY REPEATED J.

Kihara

et

POWDER al.

AL.LOYING

FORGING

(llniversity

of

Tokyo,

forging, with a load capacity of 500 tons was used to process Cu-Ag and a range of Al alloys.

Tungsten

heavy

DISTORTION SINTERED Upadhiya,

PHASE

(Pennsylvania

State University, USA) Shape control and dimensional

stability

in sintered W heavy alloys were discussed with regard to properties and applications in the light of the proportion of liquid phase formed during sintering. Investigations of microstructural evolution, grain size distribution and slumping. of WCu-Ni alloys were described. Effects of powder and liquid phase characteristics and process conditions were studied. A general model was proposed. DISPERSION

STRENGTHENING

TUNGSTEN-IRON-NICKEL

OF

ALUMINIDE

COMPOSITES R.M. German

et

al.

University, USA) The development

(Pennsylvania

the

arts

State

of W heavy alloys

as

substitutes for depleted IIw;tsdiscussed with reference to adiabatic shear. Note was taken of efforts to strengthen the matrix phase, by use of a Fe-N&Al matrix to attain this and the need for further strengthening. The addition of dispersoids to the Fe-Ni&l

automotive

and

was to stimulate

others.

The

non-metallurgical

MANUFACTURING TECHNOLOGY Kaufman.

(Technology

Management

industries

were

were

emphasized. for

process

rapid

of data

illustrations

were

the

on

noted.

presented

importance

regard

and

design

was

of

ferritic

which

were

structural

steel,

CURRENT

taking

Hot

densification

of

PM

and parts with to

Implementation

ferrous

plasma ferrous

alloys,

SURFACES

State University, USA) Surface ausforming of steel parts was outlined. The process is plastic deformation of the surface of steel in a metastable austenitic condition asquenched to just above the M, temperature. This improves surface densification and gives a microstructure with high strength and resistance to rolling contact fatigue. Wear properties were also improved. BY A

MICROSTRUCTURAL AFFECTING

of

and

novel

STRUCTURAL B. Weiss

RELATIONSHIPS

PERFORMANCE

OF PM

PARTS

et

al.

(Ilniversity

of

Vienna,

Vienna, Austria.) Degradation

in mechanical

PM parts, due to porosity, materials that

was

than

properties

compared

discussed.

properties

is

with

the

reduction

in

cross-section.

Interconnected

to be more detrimental

pores.

Inhomogeneity

also had an effect., region acting

as crack

inclusions.

inhomogeneities material

K. Komatsu components

effect

of

is great.er at higher

basic

AND MECHANICAL OF STAINLESS STEELS et

al.

(Engineered of

properties steels

SYSTEM

was

M.L. Kelley. (General

mechanical

of

Sintered

Co., USA.)

investigation

mechanical

effects

sites,

pores or

strength.

CORROSION PROPERTIES

An

The

of

of high

initiation

which may also start at secondary slag

It was

in

isolated

porosity

of

with

reduction

sintering

Corp, ISA)

and

Processing

by traditional

stainless

LOW PRESSURE

Motors

with

Structure property relationships

porosity

(Pennsylvania

DIE LUBRICATION

for

used

reviewed

was discussed.

load bearing

OF HIGH DENSITY

G.R. Stoudt.

processes were

pores were shown

R.A. Queeney,

HIGH VOLUME

Carp, Petaluma, I‘SA.)

consolidation.

disproportionate

processes

STEEL

HOT

PROCESSES

materials

shown

in ferrous

WEARRESISTANCE

fatigue low alloy

unconventional

and for product

AUSFORMED

and with

AND ADVANCED

densification

wrought

hnovations

Wear

compared

pseudo-HIP

will be required.

manufacture.

core.

properties

of

effects

PM

was

as

which

reviewed

hardness

note

was discussed.

EXTERNAL

the

Surface

C and there was high ductility

such

use will be made of computing decision

used.

was

sintor

particular

Management

critically

to changes

and

was

powder

press,‘single

techniques

AND FUTURE

management

single

AG

high density

and

MANUFACTURE

facilitate

A

methods,

NEW MANAGEMENT

Extensive

reported.

with

3.5’kMost,eel

Some

analysis was

of parts

prealloyed

A Bose. (Parmatech

control

new technology.

PARTS

Production

L)emag

PM

Process

Dependence

dissemination showed

in

discussed.

and statistical

computers

(Mannesmann Germany.)

DENSIFICATION

and Associates, USA ) Possible future developments

SINTERING

Huttentechnik, from

and

BY

STATE

K.H. Lindner.

in

PARTS

AND THE NEW

compaction

PM GEARS

SOLID

90 Rockwell

A REVIEW OF FUTURE

SM.

lower

systems.

method

use of metal powders.

manufacture

HEAVY ALLOYS

R.M. German.

object

Future

AND

IN LIQUID TUNGSTEN

industries,

applications,

were

were given from food

H.A. Tews. (Technology Associates, USA)

alloys

GRAIN SIZE VARIATION

chemical

in non-

applications,

Examples

monitoring

Tokyo, Japan.) It was reported that repeated powder forging had been used to prepare nonequilibrium and nano-structured materials, A novel machine for repeated powder

A

uses of metal powders,

described.

J.M. Torralba

pressures due to reduced die wall The system could be fitted to the feed shoe and utilises existing

HIGH DENSITY

pressed/non-sintered

POWDERS

allows

ENHANCED

SF. Claeys. (Pyron Corp, USA.) PREPARATION

system ejection friction. powder control

POWDERS

Mechanical alloying

system, for use 111 where powder and, was described. The

1000

corrosion

of 410L

after

belt

described. hour

properties

salt

and

and

or

434L

vacuum

Results

of

the

spray

tests

on

were present,ed.

MPR April 1997 47