Metallurgical Question

Date 10-15-2003 13:13

SSBN,
Maybe I'm missing something in your question, but what's wrong with using the A36 to 340L combination? It seems to meet all the criteria you mentioned and is easily weldable with 309L filler metals. The differences in Coefficients of Thermal Expansion is usually absorbed by the higher ductility of the 309L and careful planning of weld sequencing can reduce the practical differences.

Chet

By pino

Date 10-15-2003 13:17

I dont mean to be a stickler but do you mean 304L stainless Chet.

By CHGuilford (****)

Date 10-15-2003 16:50

Why yes I did! Thanks for pointing that out.

By GRoberts (***)

Date 10-15-2003 14:56

201L and 304L, are both austenitic stainless steels. They will obviously have a higher coefficient of thermal expansion than the mild steel. As Chet mentioned, it is usually not a problem during fabrication (unless you run into warping problems), but it can be an issue if the part sees thermal cycles that can cause fatigue cracking. Power plants often use an inconel pipe in between ferritic or martensitic steels and austenitic steels in order to reduce the magnitude of themal stresses. The disadvantage of martensitic stainless steels is that they will take longer and be more expensive to weld in that most of them require a preheat, and all of them (that I'm familiar with) require a post weld heat treat. As far as galvanic issues, here is a fairly complete galvanic series. It doesn't look like there is much of a difference.

http://www.corrosionsource.com/handbook/galv_series.htm

An alternative suggestion would be to use an econonmy duplex stainless steel like 2205 (UNS S31803). (Unless it gets exposed to high temperatures). It will be stronger than austenitic (so it could be made lighter), has a CTE closer to mild steel than austenitic, and doesn't need a PWHT like martensitic. It might not be the way to go if it needs good formability though.

By ssbn727 (*****)

Date 10-16-2003 04:17

Thanks GRoberts!

The only questions I have about this alloy are whether or not it has at least the same or close enough to the amount of magnetic permeability as the A-36, and if costs, availability are close enough to either the 201L or 304L stainless... I'll look into it for sure!!! Again, Thanks!!!
If anybody has any other suggestions, please let me know...
Btw, Chet - the original specs called for 201L but, I agree with you on the 304L... The structural engineer was trying to convince me the other day about why the 201L would be better but, the differences were pretty minute except for the availability, and weldability issues so, I decided to find out if there were any other alternatives that would better suit this application... To tell you the truth, I was'nt too impressed with his explanations as to why he chose to go with these choices when this design is to be mainly used as a temporary test bed so to speak with further improvements to become incorporated into the final design from the test results achieved with this design... I know this sounds like a confusing design but, I promise you that when I get permission tomorrow to release more of the details, and the purpose of this structure, I'll share it with all of you!!!

Respectfully,

SSBN727 Run Silent... Run Deep!!!

Respectfully,

SSBN727 Run Silent... Run Deep!!!

By GRoberts (***)

Date 10-16-2003 15:04

These are just approximations, as the magnetic permeability will vary within the chemical analyisis specification, method of manufacture, etc, but typically, the 304L and 201L are non-magnetic. They might have some residual ferrite, or strain induced martensite, but it will be much less than A36. I would guess that the permeability would be 0-25% of the A36. The duplex stainless steel is supposed to be approximately 50% ferrite and 50% austenite, but again, it can vary. Typically anywhere from 30-60% austenite with the remainder ferrite. Martensitic stainless steel should have a magnetic permeability close to that of A-36, as they are both fully magnetic. (Except for some possible minor amounts of retained austenite that may be present).

One example of this is for a Carbon steel block, or martensitic steel block, we have a lifting magnet here that can lift a 8" x 12" x 14" block, but in duplex, it can't lift the block, but it can lift one half after a saw cut. I haven't tried it on austenitic yet, but the piece it can lift would have to be smaller yet.

By ssbn727 (*****)

Date 10-17-2003 12:40

Hi everybody!
The Curse of the "BAMBINO" has struck again!!! Another Thriller in the Bronx!!! What a Great Team those Boston Red Sox are!!! I mean that sincerely!!! It could've gone either way... wait a minute! I apologize for that outburst but, I just could'nt help it!!! GO YANKEES!!!
Anywho, now that I got that off my chest, I can now somewhat (yes and no) freely talk about this and another project... You've heard of the "Maglev" or magnetically levitated high speed transportation system that has been designed and put to use by both the Germans, and the Japanese... Well - the United States is getting back into the game again also!!! I say this because, quite a few years ago we were at the cutting edge of this technology... As with alot of other well intentioned advances in new technology, the U.S. abandoned the project because of a variety of "reasons" so to speak but, mostly for lack of funding from congress...
There are many benefits with having a system like this because, of the time savings involved when one does alot of regional flying, makes long commutes in many regions where congestion is the norm, and weather plays havoc to flight schedules, and some regional airports are ever-increasingly expensive to fly out of, just to name a few... just think about it - being able to travel from Chicago to Detroit in 90 minutes by land!!! No more crowded runways!!! What a concept!!!
I'm not going to spend anymore time trying to sell this concept so, I'll just get to the point... There are mainly 2 tested, and proven designs for this new method of transportation. The German design is the one that was chosen to implemented here in the U.S. This same design has already been completed in Shanghai, China, and is scheduled to go into full service (already has started to generate revenue) in the beginning of 2004...
There were quite a few regions in this country competing to implement this project, and at the present time there are only four that show real promise... They are the Atlanta to Chattanooga project, the Baltimore to Washington D.C. project, the Los Angeles to Las Vegas project, and the Pennsylvania project... There is another project that is'nt as well known to the public which will also be implemented here in the greater Pittsburgh area... This is the one that I was referring to in my previous post... The design and Technology behind this project is totally different than the first 2 I already mentioned... The method of propulsion is the same but, how it goes about achieving this is totally new so, I'll just leave it at that (National Security Concerns)...
The Pittsburgh Section of the AWS invited the two groups to our monthly meetings so that they could present these projects for us mainly because, the amount of welding that will go into both of these designs... Normally, we have one meeting a month but, this month we had two because of the importance these projects have with respect to revitalizing the steel industry in Pittsburgh! Of course there are other reasons but, I'll leave it at that also...
The first meeting had to do with the lesser known project, and quite frankly - I was'nt too impressed with the design but then again this one is experimental in nature, and has far-reaching implications in a variety of new forms of transportation so, my guess is that the presentation was intentionally confusing...
The second Meeting was a real treat!!!
This presentation was based on how the German design is going to be implemented here in the U.S. There are alot of factors as to why Pittsburgh has the edge over the competition but, others may disagree so-maybe it would be better to discuss that some other time...
65 to 70% of the project costs will be in the engineering/design, and fabrication/construction costs mainly for the "Guideways" where the "Trains" levitate over. This is where we can lower alot of the overall costs of the original design, and alot of that was presented at the second meeting... Most important of all is the choice of steels to be used on this project which will be different from the "other project"...
A-36, and Core-ten will be used in the implementation of the German design. The thicknesses will vary from 5/8", 3/4", 1", and 1 1/4" respectively... Most of the welds will be fillets, and this is where it gets interesting because, each section of guideway will be approximately 204 ft. long so, controlling distortion will be paramount!!!
The section of the guideway where the train levitates over will be A-36.
The sections that keeps the train from travelling off the track from each side of the guideway because, basically each car "hugs" it as it travels, and yet also does'nt make contact with it., These two side sections will be made of Core-Ten steel...Thus, the space between the magnets, and the three sections of the guideway MUST be within some very close tolerances!!! Now this is where controlling, and minimizing distortion MUST to be done in a way that's unprecedented!!! This is where the Germans are quite hesitant in letting us know how they went about it in the first place... Allies huh??? Then why did they share it with the Chinese first??? I'll tell you why!!! it's because of our continuing record trade deficit, and basically unfair (to us) trade practices we have with China!!! Some of you might disagree with me but, that's why our manufacturing base is suffering so much these days!!! Other countries also do'nt play ball with us on level playing field but, China scares the crap out of me when I think about all of those people competing against us!!! One last comment, They're still in case some of us forgot, a communist nation!!! Over two or three Billion and counting!!! Sorry about that but, it just makes me want to scream (convict some of them for commiting treason) at both houses of congress!!!
However, one of this country's brightest minds has a few tricks up his sleeves to tackle this potential problem!!! The technologies being used on this project will revolutionize (yeah, I know you heard this before but, it's TRUE) large scale fabrications such as shipbuilding, bridges, buildings, and other large scale structures as we know it today!!! The steelmakers will have to ensure accuracy and repeatability unheard of today!!! I'm sure Chet, JW, Mike, Kip and the rest of you large scale fabricators would love to see this happen in earnest!!!
FEA and advanced Metrology methods will lead the way in controlling distortion. Coupled with advanced robotic systems, and cutting edge welding processes will ensure repeatability on such a large scale...
The future implications will be far reaching when this project becomes a reality, and it looks like there are enough influential people on board that have invested into this project!!! So, I'm very cautiously optimistic that I do "see the light at the other end of the tunnel" getting closer to the revitalization of the steel industry here in Pittsburgh... Who knows, I might even start rooting for the Pirates if this goes full tilt or maybe that's just wishful thinking but, like my wonderful grandmother used to say: "It does'nt cost anything to dream!"
Looking foward to your comments...

Respectfully,

SSBN727 Run Silent... Run Deep!!!

By ssbn727 (*****)

Date 10-19-2003 15:50

GRoberts, have you seen this website?

http://www.severnengineering.com/index.htm

Good stuff!!!
Respectfully,

SSBN727 Run Silent... Run Deep!!!

By GRoberts (***)

Date 10-20-2003 01:07

Although we have a severn gage at work, I haven't had a chance to use it. It is normally brought out though, when we need to verify that a metal has little to no ferrite in it, kind of the opposite of this kind of work. Thanks for the interesting link.

By Niekie3 (***)

Date 10-18-2003 16:14

Hi SSBN727

I am a little confused by your question, but maybe I do not understand it very well.

Here are some thoughts:

1) If you weld any of the S/Steels to a C/Steel, you will have major galvanic corrosion issues. This is probably why the Germans went for the Corten rather than the S/Steel. You will get reasonable "weatherability", but without the big galvanic issues.
2) When welding C/Steel to S/Steel, especially if it entails long sections, you will almost certainly get excessive distortion. You will need to use pre-set or other methods to minimize this.
3) For relatively thin materials, there is a method of joining that eliminates distortion, called "low stress, zero distortion" welding. This process entails the heating up of certain points around the weld pool, and the cooling down of other areas around the weld pool, as the welding progresses. You may want to have a look at this technology for your application. (By the way, the papers that I have seen regarding this method was authored by Chinese researchers, if my memory serves me well. Maybe a link here?)
4) I believe that reducing the C content of steels improved their magnetic permeability. Such steels (actually irons) are typically used in the electrical transformer industry. Not only do they keep the C low, but they alloy the iron with Si which maintains it as a Ferritic structure up to the melting point. While there are problems with these steels on the impact and strength sides, it may be worthwhile looking into them. (AISI designations of: M-45, M43, M-19, M-14, M-5 - You guessed it, the M stands for magnetic material.)

Interesting application - let us know any further details as they become available.)

Regards
Niekie Jooste
Fabristruct Solutions

By brande

Date 10-19-2003 06:05

Niekie-

I was at the same meeting as SSBN.

Anyway, the corten (a non heat treated variety) was chosen because of it's similar magnetic permeability as the special alloy developed by the germans.

A very interesting project, to be sure.

I would still like to know more about this galvanic corrosion between carbon and austenitic steels. I've seen numerous welds (using 309L and 312) between these two materials last for many, many years.
Any and all info greatly appreciated!

Good Luck

brande

By ssbn727 (*****)

Date 10-19-2003 14:47

Hey Brande,
Where were you sitting at that meeting?
Btw, the Core Ten is to be used for the side plates, and A-36 for the top plates... Both of these plates are where the transport vehicle magnets run parallel with the guideway magnets that are placed incrementally on the backside of these plates (this is where the high speed polarity switching comes into play) as the vehicle levitates over the guideways on the (High speed) german design... The conflict I had was with the (Low speed) university MAGLEV project presentation that was on tuesday... Were you there also???
Oh yeah, now that you mentioned it, how come you did'nt say hello???

Respectfully,

SSBN727 Run Silent... Run Deep!!!

By brande

Date 10-20-2003 03:19

SSBN-
Sorry I missed you. Next meeting, I will be sure to find you.
I was at the thu meeting only, but was vey pressed for time due to the night turn I've been working. Left during shift to get to meeting and immediatley after meeting to get the last few hours of the shift in.
I'll be sure to look you up next meeting!!

Good Luck

brande

By ssbn727 (*****)

Date 10-20-2003 04:28

Hi brande!

Don't worry about it! I completely understand!!!
The thursday meeting was a better one anyway...
Let me ask you a question... Have you or anybody ever heard of "True Square TIG" (GTAW) process? The welding engineer described it to us at the end of the meeting most likely after you left, and I was fascinated by the way he described it as having such a constricted arc plasma that it looks alot like Electron Beam welding!!! Without a vacuum!!! I never heard of this before so, I asked him if it was more like PAW, and he said "No!!! it's more like EBW without the need for a vacuum!!! Combine this with a "Heated" GTA wire feed, automate it w/robots, and you got some awesome welding going on!!! He was also talking about using hybrid processes like GMAW/Laser welding!!!
Man! I hope we get the chance to see this!!!
This gentleman's presentation was alot clearer, and concise if you ask me... Anyway, what did you think?

Respectfully,

SSBN727 Run Silent... Run Deep!!!

By Niekie3 (***)

Date 10-19-2003 19:35

Hi Brande

Explaining the entire mechanism of galvanic corrosion would be rather tedious, but here is a bit of an explanation:

Corrosion is an electro-chemical reaction. This means that the corrosion reaction is dependent on the movement of electrons as well as the movement of positive metallic ions. To control corrosion, you need to reduce or eliminate either the movement of the electrons, or the movement of the metal ions. Typically by either placing an electrical insulator like paint in the path of the corrosion products, or trying to "kill" the anodic or cathodic reactions.

Some metals form metallic ions much easier than others. This tends to make them more prone to corrosion. When placing two metals that have differing ease of forming metallic ions, in contact with each other, the one that forms the ions more easily, tends to corrode much faster, while the one that form ions more difficult will be "'protected" by the corrosion of the other metal. (That sentence sounds terrible!) This effect is called the galvanic effect.

It is the same effect that is used in batteries, to generate electricity.

Regarding the fact that many such galvanic couples do not corrode, lies in the fact that you need an electrolyte for the corrosion to occurr. If you can eliminate the electrolyte (e.g. Water) you will not have corrosion. In the application concerned (outside in the rain etc.) you will not be able to eliminate the electrolyte effectively.

Hope this helps

Regards
Niekie Jooste
Fabristruct Solutions

By ssbn727 (*****)

Date 10-19-2003 14:07

Hi Niekie!
I agree that the original choices made for the design of this (low speed) maglev system did'nt make sense as far as matching the selected metals...
I recognized that as soon as the structural engineer gave us (AWS Pittsburgh Section) a presentation regarding this system...
Remember the last time we discussed galvanic corrosion???
When I heard the choices this gentleman made, I immediately thought of you and the others in the thread regarding the weld overlays...
During the presentation, this person took questions, and my hand was up in there immediately!!! I asked him why his group decided to choose the base metal types with respect to the critical factors that had to be considered... Both the Galvanic compatibility, and Magnetic permeability were an issue in their choices that stuck out like a sore thumb!!! He gave us a powerpoint presentation complete with their assesments, and calculations. Oh yeah, the low speed guideways were assembled in about 50ft. sections, and the high speed MAGLEV Inc. guideways are to be assembled in 204ft, sections.. In case anyone is confused, these are two totally different designs!!!
The structural Engineer's response was'nt satisfactory as far as I'm concerned!!! If anything, some of the alternatives were better choices and yet, none were satisfactory either!!! Basically, his rationale for these choices were, and I quote: "Well - this is only going to be a temporary - experimental demonstration guideway so, after all of the analysis is completed, the track will no longer be necessary" he also added that "by "cold working the material prior to fabrication, and assembly then performing PWHT (Annealing), they could minimize the gap between the two dissimilar steels as far as the magnetic permeability was concerned". Although he explained that well, I challenged that explanation because he avoided the galvanic compatibility issue - by later asking him: "Well did'nt you just finish stating before that the university where this is being installed, will inherit this system. They would put it to use by incorporating this system into their expansion plans as a shuttle from the parking lots to the variety of new buildings scheduled to be added to their campus?"
His response was: "Well - that's why I'm asking for any suggestions to tackle some of the issues the design has problems with."
I found that hard to believe coming from a structural engineer that had previously done work for the Office of Naval Research!!!
This is mainly the reason why I posted the question on this thread...
For anyone that does'nt understand what Niekie, GRoberts, Chet, and I are talking about when we mention the Galvanic compatibility, and later Magnetic Permeability - Please refer to this website which is one that's written so that most people can understand...
http://www.corrosion-doctors.org/Aircraft/galvseri-compat.htm
In this chart Iron, wrought, gray or malleable, plain carbon, and low alloy steels (A-36 is included in this group) have an anodic index(V) of roughly 0.85 .
The 18% chromuim steels have an anodic index(V) of 0.50, and the 12% chromium type steels are 0.60 respectively
The top part of this page explains that for "Harsh Environments" such as outdoors, high humidity, and salt environments fall into this category.
Typically, there should NOT be more than a 0.15V difference in the anodic index when matching these metals...
Since these guideways are outdoors, this design falls into the "Harsh Environments" category... The differences are self explanatory!!! Way TOO MUCH!!! Now, if certain corrosion mitigation methods are used such as cathodic protection, and choosing the appropriate coatings then, the potential for galvanic corrosion could be minimized while at the same time if properly done, minimize of even eliminate the risk of distortion by the choice of coating... Now I do like what MAGLEV Inc. is incorporating when they assemble their Guideway sections. They use a "passive" method of vibratory stress relief as the welding takes place in order to reduce the residual stresses, and eliminating the need for PWHT...
Magnetic permeabilty is another important factor as is the requirement for handling cyclical loads in emergency situations whereby if the "Train cars" or transport vehicles temporarily lose levitation because of a loss of electrical power fed by the guideways or the computerized high speed switching systems that pulse the magnetic fields in "waves" fail, the train will have wheels that will make contact (run by back up battery/fuel-cells for power and on board computers for redundancy), and then mechanical/magnetic emergency braking systems will be used to stop the train or transport vehicle until the restoration of power. This poses another potential issue which was also incorporated into the design by also having the ability to deploy a specialized maintenance vehicle to repair/replace any damaged coating surface area of the guideway and the brake pads also... So Niekie, those "M" alloys you suggested may or may not be appropriate for this design but, I appreciate the suggestion nonetheless, and I will look into them!!! When I find out more, I'll post my findings
As GRoberts and Niekie mentioned the metals chosen did not have the same magnetic permeability as the A-36 CS does...
However there are a multitude of alloys that have higher magnetic permeability rates than A-36 but, costs/availability must be taken into account when considering the amount of steel that's necessary to construct miles of guideways...

This site explains magnetic permeability in simple terms, and this company's offerings are: CO-NETIC AA alloy or NETIC S3-6 etc.
http://www.magnetic-shield.com/faq/pma.html
There are others but, I really like this one on certain stainless steels:
http://accelconf.web.cern.ch/AccelConf/p91/PDF/PAC1991_2322.PDF

I like the Japanese design better myself but it also has some issues!!! What I really do not understand is why the MAGLEV 2000 of Florida project's design, and technology was not the final choice of the "powers that be" when they gave the go ahead for the implementation phase of this relatively new transportation system!!!
Unlike the German, and Japanese design, the MAGLEV 2000 of Florida project is TOTALLY AMERICAN TECHNOLOGY!!! Man! this system makes a hell of alot more sense because of the flexability of this system!!!
Now that I've looked into the alternatives to the German "Transrapid" system, I cannot help but wonder why the American designed system was'nt chosen for implementation!!! I think the rationale for choosing the Transrapid system was that the MAGLEV "attraction" levitation propulsion technology, being further along in demonstration testing than the original "repulsive" superconducting propulsion technology which Physicists Dr. David Powell, and Dr. Robert Danby not only invented back in 1966 but, also has been implemented already in Japan!!! Go Figure!!! Thus, this was the Justification from the FRA to choose the German system over our own for implementation!!!
TOO much politics were involved in the decision making process if you ask me!!! Boy did we (The U.S.) ever drop the ball on this way back in 1975 when we abandoned the initial research!!! All of that money wasted on the superconducting super collider in texas that was abandoned!!! Just think of how our economy would've benefitted if we were already working on a second generation system by now!!!
Lawrence Livamore National Labs have come up with some pretty interesting work on the possible next generation of MAGLEV technology called: "Inductrack"... A good explanation below on their webpage..
Here are some interesting websites regarding MAGLEV 2000, and other MAGLEV projects:
Lawrence Livamore Labs "Inductrack"
http://www.llnl.gov/str/Post.html
http://www.maglev2000.com
http://www.faculty.washington.edu/jbs/itrans/powelldanby.htm
http://www.faculty.washington.edu/jbs/itrans/ammaglev.htm
http://www.faculty.washington.edu/jbs/itrans3.htm
http://www.faculty.washington.edu/jbs/itrans37.htm
http://www.monorails.org/tMspages/TPM2000.html
http://www.wsdot.wa.gov/ppsc/research/TRB_Special/TRB2003-001083.pdf
http://www.pref.aichi.jp/kotsu/rinia/index_e.html
http://www.rtri.or.jp/index.html
http://www.transrapid.de/en/index.html
http://www.swissmetro.com/en/00_Home/index_E.htm
http://www.magnemotion.com/index.shtml
http://www.kyrene.K12.az.us/itech/amsitech/activities/maglev/links.htm
http://rip.trb.org/broese/dproject.asp?n=6896
http://www.21stcenturysciencetech.com/articles/summer03/maglev2.htm
http://future.newsday.com/10/fmon1025.htm
http://www.amlevtrans.com/
http://dmoz.org/Science/Physics/Electromagnetism/Magnetic_Levitation/Transportation/
Here is where we stand right now in the deployment program...
http://www.fra.dot.gov/Content3.asp?P=209
http://www.fra.dot.gov/Content3.asp?P=210
http://www.fra.dot.gov/Content3.asp?P=515
http://www.fra.dot.gov/Content3.asp?P=567
http://www.fra.dot.gov/Content3.asp?P=1209
http://www.fra.dot.gov/downloads/RRDev/maglev_rod.pdf
http://ntl.bts.gov/DOCS/TNM.html

http://www.nctransportation.com/

I hope these are sufficient for reading... Actually, I have more but, then again - I think I already commited overkill with all of these web pages & websites!!! Look foward to your comments...

Respectfully,

SSBN727 Run Silent... Run Deep!!!

By CHGuilford (****)

Date 10-20-2003 13:49

Sorry SSBN but I don't have enough time at the moment to thoroughly read all you have written, I only scanned it. I did want to throw a thought out there and apologize if you've already answered it.

You are concerned with galvanic corrosion. Niekie did a good job explaining the corrosino process for metals. Basically, just think of a flashlight battery connected at both ends with a small wire. You will have an anode, a cathode, an electrolyte, and a metallic pathway.
Corrosion prevention always either protects the components from the electrolyte, electrically insulates, provides a sacrificial material, or counteracts the flow of electrons. In a nut shell, use paint, or insulation, or magnesium blocks (as on a ship's hull), or an impressed current.
The impressed current principle is similar to having 2 batteries in a flashlight but one is put in backwards. No electron flow takes place because 1.5V+ counteracts 1.5V-, so the light doesn't work and the batteries aren't used up.
I am not current (no pun intended) on the MAGLEV details. Is the magnetism generated by a current flowing through the rails or is it induced by another conductor? Is current in the rails only when the train is there? My thinking is that there would be a high voltage potential that would accelerate corrosion. Or in some circumstances it could act as impressed current and help to nullify corrosion.

Just some rambling thoughts that I haven't connected together yet (obviously) but figured I would ask anyway.

Chet Guilford

By ssbn727 (*****)

Date 10-20-2003 19:12

Hi Chet!
A very good set of analogies to use for explaining how galvanic corrosion works... No need to apologize about your thoughts because all are welcome!!! I am familiar with coatings and sacrificial materials especially used in protecting ship hulls but, I do appreciate the input...
Niekie did do a good job of explaining this particular type of corrosion, and so did you, likewise one could get another good perspective by visiting the website I posted in the previous thread...
To answer your question about how the magnetism is generated, it depends on which design we're talking about. On the German system, it is induced by another conductor, that's insulated (the magnets are also insulated from the guideway sections) from making direct conact with the guideway sections (rails) itself, and attached to magnets which are also attached to the guideway sections incrementally, and yet at this time, I cannot remember how many magnets per section are on the guideways for the low or high speed MAGLEV... This is where the computerized high speed electronic switching design is critical so that residual magnetism does'nt cause a variety of problems in the long run... The impressed current principle should be incorporated into the design but, at this point I could'nt tell you with confidence that the designers have implemented this method of nullifying corrosion into any of these systems... The steels would also have to be manufactured using an improved method, parameters that would guarantee uniformity, repeatability as far as their composition, grain structures are concerned, and be free of any anomolies as far as the finishes are concerned for every plate to be used!!! I do not know if they're working with USX on this athough, I would like to think that they have considered this... These thoughts you have offered are good ones, and the next time I talk to these people, I'll be sure to ask them about it... On the other system designs, this may be different so, if you have an interest, and have the time (who does these days), visit some of the websites in the previous threads I posted to see them.
With the current federal budgetary constraints, and the "black hole" created by the Iraq reconstruction efforts, supporting the troops which is a must for us in order to establish stability there, nonetheless is devouring an ever growing part of our current budget, I do'nt see any final decision made in the near future that will further provide funding on this MAGLEV implementation project until this "black hole" is "plugged money tight"!!! Anywho or is it way? Thanks for your input and your questions/thoughts Chet!!! I hope that I was able to answer some of them... Look foward to reading any other thoughts on this subject...

Respectfully,

SSBN727 Run Silent... Run Deep!!!