Page 481 - 04. Subyek Engineering Materials - Manufacturing, Engineering and Technology SI 6th Edition - Serope Kalpakjian, Stephen Schmid (2009)

Section 17.8 Economics of Powder Metallurgy 46|

TABLE l'I.6

Forged and PM Titanium Parts and Cost Savings
Weight (kg)
Cost savings
Part Forged billet PM Final part (%)
F-14 Fuselage brace 2.8 1.1 0.8 50
F-18 Engine mount support 7.7 2.5 0.5 20
F-18 Arrestor hook support fitting 79.4 25 12.9 25
F-14 Nacelle frame 143 82 24.2 50

CASE STUDY l1.l Powder Metallurgy Parts in a Snowblower

A collection of parts in the freewheeling steering system produced to a net-shape peripheral geometry that is
of a commercial snowblower is shown in Fig. 17.24. not practical or economical with other manufacturing
Among the 16 PM components, the sprocket is the technologies. The material used is FLC4608-70 steel
largest, at around 140 mm in diameter. (prealloyed iron with 1.9% nickel, 0.56% molybde-
The final assembly incorporates a stamped steel num, and 0.8% carbon with 2% admixed copper)
frame, bronze and plastic bearings, and a Wrought- with a tensile strength of 480 MPa and a density of
steel axle to produce a highly functional and low- 6.8 g/cm3. Part numbers are pressed into the face of
cost machine. Unique features compatible with PM the components as a simple means of identifying
manufacturing were incorporated into the design to them. Two of the components are made with especially
enhance functionality. close tolerances: The pawl latch gear has a 0.15-mm
The PM components in the assembly range from tolerance on the pitch diameter, with 0.11-mm PD to
single-level parts with fixed features on punch faces ID run-Out and 0.025 mm tolerance on the bore; the
and core rods to intricate multilevel parts with 32-tooth sprocket has a thin-walled 57.75 mm long ID
complex die geometry, core rods, and transfer punches with a 0.05-mm tolerance. Both the paw] latch gear
that form unique features and manage the powder for and the sprocket achieve a density of 6.7 g/cm3 and a
local density control. The clutch pawl, for example, is tensile strength of 690 MPa.

FIGURE l1.24 Collection of PM parts in a commercial
Snowblower.