recent technology of powder metallurgy and applications

8/18/2019 Recent Technology of Powder Metallurgy and Applications

1/32

Recent Technology of PowderMetallurgy and Applications

PRESENTED BY AJAY SR!ANT" #$$%$$&''%(

J M)RA** #$$%$$&'$+(

S)M)!" S"AN!AR PANDE #$$%$$&',-(


2/32

ntroduction

Powder metallurgy has grown with the expansion ofvarious industries since 1950. The expansion of theautomotive industry especially, which came from the

U.., has !een a !ig in"uence.

#owadays, over 90$ of powder metallurgy productsare used in the transportation mar%et. &ecently, theautomotive industry is in the trend of the post'oil due

to increasing environmental concerns, andtechnologies for reducing fuel consumption have!een rapidly developed, such as lightweighttechnology and engine downsi(ing forenvironmentally friendly vehicles.


3/32


4/32

.unda/ental Process ofPowder Metallurgy

Powder metallurgy -P*/ is a materials processingtechnology to create new materials and parts !y diusingdierent metal powders as raw ingredients through thesintering process. Products are created !y P* using the

!asic process shown in .igure $.


5/32

.eatures of P0M

The features of P* can !e seen in the following +ve areas

1/ alloys can !e created from high melting point metals, includingtungsten, moly!denum, and tantalum2

3/ metalnon'metal composite materials as represented !y 4emented4ar!ide, cermet, and friction materials can !e created2

/ composites of metals that do not dissolve into each other, such ashigh thermal conducting materials -674u, *o74u/, high density alloys,and electrical contact materials -8g74u, 4r74u/ can !e created2

/ porous materials, such as oil'impregnated !earings and +lters, can!e created2 and

5/P* has excellent economic e:ciency !ecause products can !eformed !y pressing powders in molding tools.


6/32

Position of P0M in /aterialprocess technologies


7/32

Trends of P0MTechnology

;n the overall material processtechnology industry, there are a varietyof products utili(ing P*. 4urrently, mainP* products of leading processing unitscomprise structural parts , tri!ologicalparts -oil'impregnated !earings, wear'

resistant parts, and high'temperatureheat'resistant wear'resistant parts/, andmagnetic parts -soft magneticmaterials/.


8/32

$1 Structural parts

tructural parts ma%e up a large portion of P* products. Their mainingredient is iron alloys.


9/32

$1a( "igh2StrengthMaterials To develop materials with a high strength, !eginning with the e74u74 system, alloy

elements were added with high hardena!ility, and optimi(ed methods for addingthese alloy elements to improve the materials> mechanical properties.


10/32

$13( "igh2di/ensionalPrecision Parts

The applications of sintered materials have expandedgreatly owing to the development of high'strength

sintered materials -


11/32

$1c( Sinter2"ardeningMaterials

or the iron'!ased sintered parts, sinter'hardening materials producedwithout )uenching process have !een in practical use. The sinteringprocess of high'strength sintered materials includes a step of applyinghigh temperature and another step of applying high temperature tostrengthen the structure.

By com!ining two heating steps to one, the )uenching process can !eshortened and the energy consumption is also saved. 6e evaluatedhardena!ility dependent on the cooling step and investigatedcompositions of materials that ena!le the )uenching process to !eomitted.

4onventional sintered materials must !e sintered in furnacese)uipped with rapid cooling apparatus to form martensiticmicrostructure !y the cooling step. ;f the process can !e shortened !yusing regular furnaces, its economic e:ciency !ecomes even greater.


12/32

The development of a material that can formmartensitic microstructure at the cooling rate of regularsintering furnaces. .igure , shows an overview of44T-4ontinuous 4ooling Transformation/ diagram of

this material.


13/32

.igure - shows the micro structure of thedeveloped material.


14/32

%1 Tri3ological Parts

These parts are strongly related to a!rasion andlu!rication. The +eld has grown as original P* alloycompositions and material microstructure are !eingactively utili(ed2 these developments could not have!een accomplished with wrought steel.

=il'impregnated !earings and wear'resistant parts aswell as high'temperature heatresistant, wear'resistant

parts are applications of P* technology.

The applications of oil'impregnated !earings havegrown through their use in home appliances, audioe)uipment, o:ce e)uipment, and automo!iles.


15/32

Tri3ological Parts#contd1(

&ecently, advanced technologies that supporthigh contact pressure and low coe:cient offriction for use in environmentally'friendly

products, such as ;4T-;nformation and4ommunication Technology/ e)uipment andconstruction machinery have also !eendeveloped.

;n the area of wear'resistant materials, valveguides and valve seats, which conventionallyhave !een cast, are !eing replaced !y low'costyet high'performance sintered parts.


16/32

%1a( "igh contact pressure3earings

Doint !earings for construction machinery,as represented !y oil'pressureexcavators, are used under low speedand high contact pressure conditions. Thecontact pressure can reach a maximum

of @0 *Pa. ;ron'!ased !earings whichhave high strength are used under such ahigh'contact pressure environment..igure + shows sei(ure load of dierentiron'!ased !earings.

8s comparison, the contact pressure

limits of conventional wrought steel!earings are also shown. 4onventionalwrought steel !earings are applied withgrease. Aowever, grease must !e appliedfre)uently, and in our testing the greaseran out and the !earings sei(ed.


17/32

8lso, conventional iron'!ased sinteredmaterials have a high coe:cient of friction,and sei(e up after exceeding a contact

pressure of 50 *Pa. ;n contrast, the coe:cientof friction of our newly developed


18/32


19/32

%13( "eat2 and 5ear2Resistant Materials

Falve guides and valve seats,which are structural componentsof an engine valve train, arerepresentative of widely used

heat' and wear'resistant sinteredalloys. .igure $' shows theregion using the valve guide andvalve seats.

By the increasing demand for

improving wear resistance andlowering cost since the 19@0s asfuel e:ciency and engine powerimproved, the use of sinteredmaterials that can meet !oth ofthese demands has expanded.


20/32

%1c( 6al7e 8uideMaterials The environment where valve guide are used has !ecome severe

!ecause of miniaturi(ation of itself, downsi(ing of the diameter, andrising temperature of exhaust gas in order to increase fuel e:ciency.8lso, sintered materials has !ecome used for valve seats !ecause thewear resistance of conventional materials, such as cast iron, were found

to !e insuf +cient as the usage of unleaded gasoline !ecame popular. The microstructure of


21/32

&1 Magnetic Parts

;n recent years, to support ;4T e)uipment that rapidly continuesto !ecome faster, use higher fre)uencies, !ecome smaller anddenser, and save more energy, achieving high permea!ility andlower core loss in the high'fre)uency region is !eing re)uired for

soft magnetic materials.

This means that the needs of advanced magnetic materials aregrowing for !oth present'day automo!iles, in which electroniccontrols are !ecoming increasingly advanced, and for next'generation hy!rid electric vehicles and electric cars.

8dvances in the development of technologies including sinteredmagnetic parts consisting of structural and magnetic materials,and powder cores -or soft magnetic cores G*4H/ that featurelow core loss in high'fre)uency regions have !een developed.


22/32

&1a( Sintered Magnetic 9oreMaterials

The direct'current -I4/ magnetic properties of a sintered core areprimarily determined !y the sintered core>s composition of materials, itsdensity, and its crystal particle si(e. 8 pure iron sintered core has highmagnetic "ux density.

This magnetic "ux density is strongly related to the o!Eect>s purity anddensity. Therefore, a high'density sintered core using highly pure ironparticles has a high magnetic "ux density. 6hen P is added to thismaterial, its crystal particle si(e grows, resulting in high permea!ility.

;ron'nic%el'!ased sintered material, which has even high permea!ility,

is called permalloy. ;t is used in magnetic shielding materials, etc. Thealternating'current -84/ magnetic properties of a sintered core arelargely related to the shape of the part, as well as the composition ofmaterials and the density of the sintered core. 4ore loss occurs whenthe sintered core is used in an 84 magnetic +eld.


23/32

8s shown in


24/32

.igure $& shows the rotor core used in a hy!rid electricvehicle. ;ts outer circumference uses a sintered magneticcore material made of pure iron. The interior portionre)uires a high degree of strength !ecause motor tor)ue is

directly transferred to the shaft. Thus it is composed of e7#i74u74'!ased material, and is com!ined into a single !ody!y diusion !onding at sintering.


25/32

&13( Powder 9oreMaterialsPowder magnetic cores are insulated !y

100'Jm magnetic powder particles one

!y one. By reducing the thic%ness of themagnetic material down to 0.1 mm, the

material can lower the core loss in an 84magnetic +eld. .igure $: shows an

schematic diagram of the elementsforming the powder core. The surface ofpure iron powder particles a!out 100 Jm

in si(e are coated with an inorganicinsulator. 8fter they are mixed with asmall amount of organic resin !inder,they are compression'compacted andheated to produce the magnetic core. Therefore the powder core, unli%esintered magnetic core materials, cannot!e expected to !e densi+ed in thesintering process. Thus densi+cation isre)uired during the compacting process.


26/32

.igure $- shows the solenoidcores used in common'railinEectors of diesel engines.Powder core material is

applied to these cores. Thisproduct is an electromagneticpart that precisely opens andcloses the fuel inEector in thesystem improving the power ofdiesel engines and suppressingtoxic components in exhaustgases. or such a product, highmagnetic "ux density and lowcore loss are re)uired.


27/32

:1 Ne;t28eneration "igh2Perfor/ance Parts

*icroni(ation is seen as the next'generation technologyfor the +elds of information home appliances and the life

sciences. Ievelopment of technologies for compactingmicro parts that are di:cult to industrially produce with

machining and metal inEection molding -*;*/.

8nother area is the development of products that can

directly contri!ute to the +eld of environmental energy.

8dvancement in the development of thermoelectricconversion technology that regenerates energy from

waste heat and thermoelectric conversion modules asproducts utili(ing this technology.

: a( New Technologies for "o/e


28/32

:1a( New Technologies for "o/enfor/ation Appliances and *ifeSciences< 9o/pacting Micro Parts

;n recent years, demands of miniaturi(ation andthinner component parts have !een growing,corresponding to the increase of miniaturi(ed andmulti'functional digital home appliances or advancedmedical e)uipment. Aowever, conventional die4ompacting method !y free'+lling raw powders intodie cavities cannot meet the demands for smaller andthinner parts due to eects including frictional

resistance and Fan der 6aals force produced !etweenparticles and dies, and the eects of air. Thus we havefocused on metal inEection molding -*;*/ of rawmaterials, which are superior for molding parts withcomplex shapes.


29/32

#ew powder compacting methods!y using "ow molding that utili(esthe plasticity of the !inder insidea heated die. .igure $= showsthe compacting process for micro

parts. The movement distance of"uid compounds are shortened toan extreme degree, and the lossof pressure is minimi(ed. Thisprocess allows the compacting of0.035 modules that surpass 0.1

modules, which represent thelimit of micro gears made !y theconventional P* method. =urnew methods can also producetwo'stepped gears with complexaxis.


30/32

.igure $+ shows the appearance of a micro gear formed !y the a!ove compactingmethod.

.igure $4 shows the trend in compacting technologies and material technologiesin powder metallurgy in the future. The technologies developed !y AitachiPowdered *etals ma%e it possi!le to achieve a high level of productivity in themicro si(e region not possi!le with conventional compacting and machiningtechnologies. 8lso, !y com!ining the technologies with micro die manufacturing

technologies and nanocrystal powder, we are anticipating high'performanceproperties such as super high strengthening.


31/32

References

Recent Technology of PowderMetallurgy and Applications

-&eview paper 3/!y Tadayuki Tsutsui( Aitachi Powdered *etals 4o., Ktd./

Th > Y f h


32/32

Than> You for theopportunity

recent technology of powder metallurgy and applications

Documents