In general, the solder joint quality suffer from poor solderability of 
Alloy 42, because of the lower solderability of nickel and iron. In order to 
achieve the same good joint quality as normal soldering (60/40 to Copper), 
usually higher reflow temperatures and a longer time above liquidus 
temperatures are needed. Several published technical articles  believe that 
the increase in lead stuffiness is the direct cause of the  reduction in 
fatigue life.

     As lead stuffiness  ( ^ increase)  Fatigue life ( v decrease)
     The order for stiffness of common lead material are:
     Cu <  Kovar < Alloy 42

Michael Yuen
PE (DfM)
[log in to unmask]


 ----------
From: TechNet-request
To: Technet
Cc: leot1
Subject: Re: Alloy 42
Date: Tuesday, April 16, 1996 7:25PM

     Alloy 42 has/is widely used on many electronic components. As long as
     your lead finish is correct (i.e. correctly plated or tinned) and you
     do not have an oxidation problem, then you should have no problems
     soldering to those parts. Could your customer have been referring to
     solder joint cracking problems on parts with Alloy 42 base metal?
     Werner Engelmaier and others have published several technical articles
     documenting the solder joint cracking problems of Alloy 42 components.


     Dave Hillman
     Rockwell Collins
     [log in to unmask]


______________________________ Reply Separator
_________________________________
Subject: Alloy 42
Author:  [log in to unmask] at ccmgw1
Date:    4/16/96 6:32 PM


We have a customer who says that a previous supplier had problems soldering
some fine pitch components (15 mil) because the lead material was "Alloy
42".  They had a tin/lead coating (85/15).  They were also told that many
component mfgrs are going to be using this material.

We are not familiar with this lead material but since it is solder coated do 

not hink it should be a problem.  Anyone have any knowledge or experience in 

this area?

Thanks in advance for your consideration.

Leo Reynolds
Electronic Systems, Inc.