Pat,
Most stainless pots are 304, some 316 and I haven't really seen much difference in dissolution between the two. Most likely (SWAG) it's primarily the nickel going into solution. Temperature certainly plays a role... it really doesn't happen at RT (LOL) but of course increased temperature above liquidus will accelerate reaction(s). How much, I'm unsure... I guess that depends (standard technical disclaimer for Technet, no?)
Ed Popielarski
Engineering Manager
970 NE 21st Ct.
Oak Harbor, Wa. 98277
Ph: 360-675-1322
Fx: 206-624-0965
Cl: 949-581-6601
https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Goodyear, Patrick
Sent: Tuesday, April 16, 2013 3:29 PM
To: [log in to unmask]
Subject: Re: [TN] Useful wave solderpot life when using leadfree solder
Ed, very interesting, I had no idea the aggressiveness of SAC305. What types of Stainless Steels does it attack, is one type more susceptible then another, does temperature play a role? Another reason to keep lead-free out of Nuclear Power Plants.
Pat
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ed Popielarski
Sent: Friday, April 12, 2013 8:57 AM
To: [log in to unmask]
Subject: Re: [TN] Useful wave solderpot life when using leadfree solder
Steve,
The pot isn't ususally the first casualty. The area(s) with the most flow are exposed to a significantly lower saturation, so they will go first. An analogy would be a block of salt sitting in a pond (not that I recommend doing this) vs. in a stream. The layers surrounding the block in the pond have a higher salt concentration than the water flowing passed the block in the stream, therefore increasing the rate of dissolution.
This is how lead-free solder (usually SAC305, as it's most "aggressive") ruins unprotected stainless parts. The first to go are usually the impeller and flow duct (the horizontal channel the solder flows through at the bottom of the nozzle). If you catch it before too much damage has occurred, you can have it cleaned and melonite coated http://en.wikipedia.org/wiki/Melonite , extending the life of the parts provided they remain unscratched. The impeller and shaft is usually replaced with titanium as it won't dissolve in solder(s), but they too can be coated if economy is an issue.
The reason solder pots get the spotlight is the collateral damage caused by catastrophic failure, i.e., solder leakage. It's a good idea to have stainless pots melonite coated as well. Cast iron doesn't have this problem as the iron oxide surface is insoluble... just remember to NEVER abrade (wire brush,etc. ) it!
Ed Popielarski
Engineering Manager
970 NE 21st Ct.
Oak Harbor, Wa. 98277
Ph: 360-675-1322
Fx: 206-624-0965
Cl: 949-581-6601
https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Thursday, April 11, 2013 6:55 PM
To: [log in to unmask]
Subject: [TN] Useful wave solderpot life when using leadfree solder
Hi all,
Well, I’ve had a chance to look at the used wave solder machine that was bought before I arrived at my new job in Idaho, and I have a general question; what is the useful life that one can expect from a wave solderpot that has used leadfree solder?
I’ve seen by searching the internet that it could be just a few years depending on what the pot was constructed from.
I’ve primarily dealt with leaded wave soldering machines and don’t have a good history of lead-free machine life...that’s why I’m asking.
Steve
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________
PG&E is committed to protecting our customers' privacy.
To learn more, please visit http://www.pge.com/about/company/privacy/customer/
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
|
