"Ed Huntress" wrote in message
...
On Wed, 24 Apr 2013 19:09:50 +0100, David Billington
wrote:

On 24/04/13 18:16, Ed Huntress wrote:
On Wed, 24 Apr 2013 17:48:52 +0100, David Billington
wrote:

What you're describing is by far the most common way it's done.

PM can be fascinating. By mixing powders and sintering at full
diffusion temperatures, you can produce alloys that are not possible
any other way.

For example, the most exotic of the high-speed-steels: Crucible CPM
REX 121. You can't make it by melting. That stuff is HIPped, BTW.

Regarding memory, I can empathize with that. d8-)

I have a book called "The Component Contribution Engine Progress
Through
the Specialist Manufacturers" by Alan Baker ISBN 0 09 136290 3 and it
mentions the use of what they call powder forging being used by GKN to
produce conrods for the Porsche 928. The book dates from 1979 and the
928 1978 so looks like some high performance applications have been
around for a while.
Yes, I remember that. The 928 engine used a lot of advanced
technologies. Porsche was trying all their new tricks, including
running the pistons in aluminum cylinders. Unlike the Chevy Vega, they
got it right.

I mentioned the Vega engine to a mate that works in engine development
and he found it hard to believe they went all that trouble developing
the block process then put an iron head on it to save money but then
maybe that was GMs way. I do remember back in the 70s the engine had a
bad reputation.

There were several basic engineering screw-ups, some so obvious that
it was hard to believe.

You may remember the Cosworth version of the Vega, which had an
aluminum, dual-cam Cosworth head on the same engine block. Some car
enthusiast wrote a letter to one of the two big US sports-car
magazines -- Sports Car Graphic or Road & Track -- and asked how you
could tell a regular Vega from a Cosworth Vega. There was no obvious
Cosworth insignia on the car; just one little badge somewhere.

"Look under the car," said the magazine editor. "If there's a puddle
of oil under it, it's a regular Vega." d8-)


I do not know the Vega engine, but it sounds like the result of a process I
have seen too many times.
A senior executive gathers the engineering group and says, "We need to
reduce the cost of goods by $100 and pull in the schedule by 2 months. Give
me any ideas you have. Don't be bashful, we are just brainstorming here"
After some silence he says, " Oh, come on, I know you have ideas."
Finally some competent but naive fellow will meekly speak up and say, "well,
we COULD do X, but of course that would mean Y." The fellow just assumed
anyone in his right mind would never want Y to happen.
The executive who does not really understand the technical implications of Y
gets all excited, "Really! We can do that? That makes me very happy, lets do
it!"
As others around the table try to gently tell him the problem with that
decision, he is not even listening as he mentally tallies his year end
bonus.