Page 466 - 04. Subyek Engineering Materials - Manufacturing, Engineering and Technology SI 6th Edition - Serope Kalpakjian, Stephen Schmid (2009)

446 Chapter 17 Powder-Metal Processing and Equipment

______ __ ____ ________ __ _“e<\o\i‘ 40 -100
_ 200 - <@<\S)° Q
§ if
Density 5 QS) _ 35 _ 95 Q
of iron " QC) Q 9-»
Density :E OQ5 gj 3
of copper E” 150 0 _OG <; I2
9 Q? - 30 -9 _ 90 "5
175 go is g
Apparent Q, Q il? g;
Density E, Q/ _Q 8
85 E
I Copper powder, coarse 3.49 g/cm3 3 LU _
U Copper powder, fine 1.44 l' 100 _ ` 25
° Iron powder, coarse 2.75 8
O Iron powder, fine 1.40 1 E
O
O 200 400 600 800 1000 1200 3-0 3-2 8-4 3-6 8-8
Compacting pressure (MPa) Sintered density (g/cm3)
(a) (b)

FIGURE I7.l0 (a) Density of copper- and iron-powder compacts as a function of Compacting
pressure. Density greatly influences the mechanical and physical properties of PM parts.
(b) Effect of density on tensile strength, elongation, and electrical conductivity of copper powder.
Source: (a) After EV Lenel, (b) After the International Annealed Copper Standard (IACS) for
electrical conductivity.

L/D = 1.66

£88 MP8
»--.- I
.___.__,,
,,
.. i zri _ 200 L
;§?jf§`jj_ -

D/2
Q
(8) (D) (C) (Cf) (9)

FIGURE l1.Il Density variation in compacting metal powders in various dies: (a) and
(c) single-action press; (b) and (d) double-action press. Note in (d) the greater uniformity of
density from pressing with two punches with separate movements compared with (c).
(e) Pressure contours in compacted copper powder in a single-action press. Source: After P.
Duwez and L. Zwell.

l7.3.l Equipment

The pressure required for pressing metal powders ranges from 70 MPa for alu-
minum to 800 MPa for high-density iron parts (see Table 17.1). The Compacting
pressure required depends on the characteristics and shape of the particles, on the
method of blending, and on the lubricant.
Press capacities are usually around 1.8 to 2.7 MN, although presses with
much higher capacities are used for special applications. Most applications actually

(g/cm3)
Density