Powder Metallurgy Part1

7/30/2019 Powder Metallurgy Part1

1/19

February 28, 2011


2/19

THIS IS A COURSE ON

MANUFACTURING

WHAT IS THE DIFFERENCE BETWEEN:

SCIENCE

TECHNOLOGY ENGINEERING


3/19

HOW MANY OF YOU HAVEA BI-CYCLE ??

HOW MANY OF YOU HAVEOPENED IT ??

AND


4/19

1) The correct order is: debug, then ship. TRUE

2) If it isn't broken, don't fix it. FIDDLE WITH IT

3) If you fiddle with something long enough, it will break. LET IT BREAK !

4) It works if you plug it in. TRUE

5) A working example is worth a thousand manual pages. VERY TRUE !!

6) Failures occur where two parts join. TRUE

7) Demos cause failures. TRUE

8) Systems grow more complex with time. TRUE

9) If it's too complex, rebuild it. YES

10) Small parts vanish when dropped. TRUE

The Ten Fundamental Laws of Engineering

NEXT >>THERE IS NO FAILURE IN RESEARCH . . .


5/19

POWDER METALLURGY

. . . is a forming techniqueEssentially, Powder Metallurgy is an art & science of

producing metal or metallic powders, and

using them to make finished or semi-finishedproducts.


6/19

POWDER METALLURGY

. . . particulate technology isprobably the oldest forming

technique known to man

There are archeological evidences to prove that

the ancient man knew something about it . . .


7/19

History of P/M

a) How did Man make iron in 3000BC?

b) Did he have furnaces to melt iron?

IRON Metallurgy >

Quite unlikely, then how ???

i. Crushed iron ore with charcoal were heated

together in a furnace, with air blasts, and

ii. The reduced material, which would then bespongy, [ DRI ], used to be hammered to a

solid or to a near solid mass.

Example: The IRON PILLER at Delhi


8/19

P/MAn important point that comes out :

The entire material need not be melted to fuse it.

The working temperature is well below the

melting point of the major constituent,

It began with Platinum technology about 4 centuries

ago in those days, Platinum, [mp = 1774C], was

"refractory", and could not be melted.

making it a very suitable method to work with refractory

materials, such as: W, Mo, Ta, Nb, oxides, carbides, etc.


9/19

History of P/M

The art of pottery, (terracotta), was known to the

pre-historic man (Upper Palaeolithic period,

around 30,000 years ago)!

Going further back in Time . . .

Dough for making bread is also a powder

material, bound together by water and the

inherent starch in it. Baked bread, in all its

variety, is perhaps one of the first few types of

processed food man ate.

(Roti is a form of bread.)


10/19

Renaissance of P/M

The modern renaissance of powder metallurgy

began in the early part of last century, when

technologists tried to replace the carbon filament in

the Edison lamp.

The commercially successful method was the one

developed by William Coolidge. He described it in

1910, and got a patent for it in 1913.

This method is still being used for manufacturing

filaments.


11/19

Renaissance of P/M

The Wars and the post-war era brought about huge

leaps in science, technology and engineering.

New methods of melting and casting were perfected,

thereby slowly changing the metallurgy of refractory

materials.

P/M techniques have thereafter been used only

when their special properties were needed.


12/19

P/MApplications Electrical Contact materials

Heavy-duty Friction materials

Self-Lubricating Porous bearings

P/M filters

Carbide, Alumina, Diamond cutting tools

Structural parts

P/M magnets Cermets

and many more . . . such as Hi-Tech applications


13/19

Hi-Tech Applications of P/M Anti-friction products

Friction products

Filters

Make-Break Electrical Contacts

Sliding Electrical Contacts

Very Hard Magnets

Very Soft Magnets

Refractory Material Products

Hard and Wear Resistant Tools

Ferrous & Non-ferrous Structural parts

Etc . . .BACK


14/19

P/M Merits :o The main constituent need not be meltedo The product is porous - [ note : the porosity can be controlled]

o Constituents that do not mix can be used to make composites,

each constituent retaining its individual property

o Near Nett Shape is possible, thereby reducing the post-

production costs,therefore, Precision parts can be produced

o The production can be fully automated,

therefore, Mass production is possible

Production rate is high

Over-head costs are low

Break even point is not too large

Material loss is small

and Control can be exercised at every stage


15/19

P/M Disadvantages :

o Porous !! Not always desired.

o Large components cannot be produced on a large

scale [Why?]

o Some shapes [such as?] are difficult to be produced

by the conventional p/m route.

WHATEVER, THE MERITS ARE SO MANY THAT P/M,

AS A FORMING TECHNIQUE, IS GAINING POPULARITY


16/19

P/M Summarizing :

Powder Metallurgy is sought when -

a) It is impossible to form the metal or material by any

other techniqueb) When p/m gives unique properties which can be put

to good use

c) When the p/m route is economical

There may be over-lapping of these three points.


17/19

POWDER METALLURGY

Powder Metallurgy is an art & science of1. producing metal or metallic powders, and

2. using them to make finished or semi-finished

products.

on March 01, 2011


18/19


19/19

Powder Metallurgy Part1

Documents

Transcript of Powder Metallurgy Part1