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Subject:	Re: Strength of Solder Joints
From:	"Ingemar Hernefjord (EMW)" <[log in to unmask]>
Reply To:	TechNet E-Mail Forum.
Date:	Wed, 2 Feb 2000 08:58:55 +0100
Content-Type:	text/plain
Parts/Attachments:	text/plain (46 lines)

Solidification occurs within a few degrees and the most dramatic structure is built within milliseconds, and down to room you get built-in stress in the joint (quite natural). These von Mises and other stress phenomenons will sometimes decrease when the part passes first time through a temperature interval (relaxation). And next tempcycle will make the relaxation a bit further etc. To control the critical solidification by manipulating the temp rate seems to be an expensive, timeconsuming and impractical adventure, so the whole thing looks like an academic question.  My experience is that the GEOMETRY, the WETTING and TCE DIFF MINIMIZING are far more important. That's my two liras, and may not be worth more after Werner has entered the arena.. / Ingemar

-----Original Message-----
From: Clayton Gardner [mailto:[log in to unmask]]
Sent: den 2 februari 2000 00:25
To: [log in to unmask]
Subject: [TN] Strength of Solder Joints

Technet,

I have recently read in an article that the most favourable type of solder joint is formed from rapid cooling of the solder.

I am a bit confused with this as I have always been under the impression that rapid cooling of metals results in tight compact grain structures (very hard, but brittle). This is in contrast to slow cooling that forms long grain structures resulting in a stronger and tougher material (which I would have thought is what would be ideal for a solder joint - good shock resistance).

Regards....

Clayton Gardner
Engineering Manager

A.E.M.S
11-13 Fiveways Boulevard
Keysborough VIC 3173
AUSTRALIA
Ph. 61 +3 9701 5499
Fx. 61 +3 9701 5422
Mb. 0416044552
Email:  [log in to unmask] <mailto:[log in to unmask]>
WEB:  www.aemspl.com.au <http://www.aemspl.com.au>

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