PM stakes claims in the automotive world

PM stakes claims in the automotive world

I

n what was expected difficult

to be a

year for the world’s

largest automotive technology conference, SAE claimed to be very encouraged

by the results of

Stillman John

and Don White

Davidson

(QMP America), Mark Battison (Stackpole Ltd), Ryuichiro Goto (Hogan&

North

its 2002 World Congress, held in the Cobo Center, Detroit,

Chernenkoff

between March 4 and March 7.

Motors),

Although

overall

attendance

was down 14 per cent at just over 37,000,

most of the drop was said

to be due to reduced

staffing

of

America), (Ford

and Howard

(Management Technologies), PM technical

sessions. A highlight

of the luncheon

programme

presented.

Award

the

PM

industry

throng,

by

was

of the 2002 Innovation

incoming

David Schaefer

represented

Sanderow

& Engineering who organised the

booths by the 1000 exhibitors. A record 1300 technical papers were this

Russ

Research

Lab.), Jean Lynn (DaimlerChrysler

the announcement MPIF Automotive

Among

(MPIF),

and Don Brydges

President,

(See panel), while

almost exactly 1 per cent in atten-

Dave Versical, Managing Editor of

dance, paper presentation, exhibitors. Nevertheless

Automotive

annual

event

opportunity air their

and this

gave an excellent

for PM fabricators

achievements

promise of PM technology

to

News,

entertained developed

American

temperature

auto industry.

for these

and high-

sintering of advanced

materials.

replacement

Advances in gears

sinter-harden-

Discussing

the

of pearlitic malleable

cast iron for gear applications,

efforts should

Developments

in PM gears and

noted

that warm-compacted

he PM

sprockets for engines and transmis-

steels could meet the specifications

luncheon

sions formed the chief topic of the

for yield, tensile strength,

tive

first

tion

go to the MPIF

for organising

a

programme for automoand to Teresa suppliers

PM

(Keystone

session.

John

Powdered

Kosco

Metal

Co.)

However,

modulus sintered

density would

the

match the 4 per cent elongation of

significance

of density

and

to be further

elonga-

of elasticity.

have

increased

dimensional tolerance in the devel-

heat-treated

Michael Baran of Hoeganaes Corp

duty transmission components such

addressed the subject of substitut-

as gears and bearing

ing PM steels for cast iron in more detail in a later session.

races.

He

ing tensile data determined “dog-bone”

test-piece

on a vs.

The

malleable

to

opment of PM materials for heavy

PM

density

and provided

improvement

iron.

property by warm

machined round specimens, which

compaction

tends to put PM at a disadvantage.

use in the manufacture of chain-dri-

Kosco dynamic

concluded and

by

other

reviewing mechanical

ven

has been put to good

camshaft

and balance

shaft

sprockets, as reported on by Jeffrey

properties of high density PM mate-

Hamilton

rials developed by his company for

Products, Inc.). Engine manufactur-

high-performance applications. Sim Narasimhan described

ers’ efforts to produce lightweight,

developments

by

colleagues

at

Hoeganaes Corp. on PM materials

quiet, ning

(Cloyes

Gear

and

fuel-efficient, smooth-runengines were increasing

demands for accessory drive systems

and processes for gear-type applica-

to

tions, highlighting

improve noise, vibration, and harsh-

the importance

of surface contact stresses. He reviewed the improved properties

MPR May 2002

and

opened the session by focussing on

pointed out the danger in compar-

24

through

ing, warm compaction, ferrous

industry that is its chief customer. Credit

Figure 1: Warm-compacted multi-level I.T chain sprocket. (Photo courtesy Jeffrey Hamilton, CLoyesGear and Products, Inc.)

guests with his views on the competitive situation in the North

and the for the

2~h11r11

0026.0657/02/$-see

fit

into

smaller

spaces

and

ness characteristics. Reduced chain pitch and sprocket width added up

front matter 0 2002 Elsevier Science Ltd. All rights reserved.

Part of the year

when

conventionally

compacted.

He quoted the example of a multi-

Stackpole's transmission carrier cleaned up on the international prize circuit last yea& won the GrandFrjzeintheFerrouscatae~ goryofthe2OOlMPlFPartof the Year Competition, and then took the awardfor Innovation in Powder Metallugy at the European Powder Metallurgy Associations conference and exhibition in Nice.

level sprocket

with two rows of

teeth. The smaller diameter sprocket drives twin engine

camshafts,

while the larger diameter sprocket drives the balance

shaft and oil

pump system (Figure 1). Both rows of teeth were warm-compacted

in

one step to 7.25 g/cm3. This sprocket operates with an inverted-tooth chain and was evaluated in various performance

irame

G&es

tests by both Cloyes

gear and the engine manufacturer, to the need for improved mechani-

including

cal properties in the sprocket teeth.

compacted

Warm

tests with a wide margin. Cloyes’ experience in manufacturing warm-

compaction

has permitted

sprocket density to be increased to without additional 7.3 g/cm3 process steps, versus typically 7.0-7.1 for conventional increased

compaction.

hardness

The

and strength

made warm-compacted

sprockets

wear tests. The

compacted

sprocket

sprockets

warm-

passed these

has proved

positive in respect to manufacturing cost, dimensional stability, and machinability,

confirming the suit-

ability of warm-compacted

sprock-

Figure 2: Test rig for measuring gear tooth rupture strength. (After Skoglund et al.) The higher densities achieved are expected

to expand

applications

for both PM structural

Skoglund reported the results of property tests on planetary gear samples that had been prepared

at

ets for IC engine applications. Using a Cloyes PM planetary

twice engine speed. Driven sprock-

gear as a case study, Paul Skoglund

sinter-hardening:

ets warm-compacted from FLN24405 material have been in produc-

(Hoganas AB) gave an update on his company’s ongoing investiga-

0.4%

Fe-1.5Mo

tion since 1999, with about one mil-

tion of high velocity

alloyed)

+ 0.6%C.

lion already installed

(HVC). In HVC, densification is achieved by shock waves created as

strength

measurements

good candidates for balance roller-chain

Similar

drives

shaft

operating

in engines. chain inverted-tooth

sprockets made from FD-0405 warm-compacted

to

7.25

and

g/cm3,

a hydraulically

compaction

operated

hammer

that impacts the compaction

tool-

parts and

soft magnetic composites.

from two materials by HVC Astaloy

C, and D.DH-1

plus

CrM

+

(prealloyed

with 2% Cu diffusionHardness and obtained

from test bars and test gears of these materials were compared with conventionally-compacted and heattreated D.DH-1 and ID-0208 sam-

since 2000 and in North America

ing compresses the powder. Stateof-the-art equipment is claimed to

since 2001.

make HVC a viable mass-produc-

Hamilton also pointed out the advantages of higher green strength

tion method, capable of producing gears with densities up to 7.6

achieved with warm compaction

g/cm3. Other steps in the process -

loading fixture on a hydraulic test-

ejection similar

and strength values (Table 1) clear-

have been in production

in Japan

in

the manufacture of multi-level parts that are prone to ejection

cracks

and sintering, etc - are to conventional PM.

ples at densities of 6.9 g/cm3 and 7.1 g/cm3, respectively. Static tooth rupture strength measurements on test gears were made in a toothing machine

(Figure 2). Hardness

ly demonstrate the value of HVC in raising the compacted density. Increasing the density of D.DH-1 from 6.9 g/cm’ to 7.5 s/cm3 raised the hardness from HRC 30 to HRC 40 and the UTS from 900 MPa to 1500

MPa.

The

tooth

rupture

strength increased from 13.2 to 21.2 kN and was 44 per cent higher than the reference FD-0208 material. HVC

combined

with

sinter-

hardening promises to allow manufacture

of high

density,

high-

strength gears at lower costs than alternative PM processes such as double pressing and sintering.

Joseph M Capus

www.metal-powder.net

MPR May 2002

25

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