1. #1
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    Talking 20 year bodies and sub structures

    Our department has put together a truck committee to look into the purchase of a new Custom pumper. We had been exclusive to one manufacturer for years but our aluminum bodied, steel subframe truck has some major issues. The trucks subframe is covered with rust from front to back, and the rear steel subframe is lucky if it makes ten years. We do all our weekly, monthly and yearly preventative maintenance and the truck gets washed down after every call.

    We were now starting to look at stainless steel with stainless steel sub frames. We looked at a Vibra Torque system that Crimson fire has, looks great, we have looked at some other brand with springer style systems they looked good also .We heard a large department in Connecticut has a fleet HME trucks that have had a lot of mounting cracks and sub frame failures, does anyone know about that. We were going to look at there products also.

    Could someone help lead us in the right direction

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    Oh boy.Stainless can be good,PROVIDED;it's the right grade welded with the right wire.If not,you might as well have carbon steel.No perfect system I'm aware of.Road chemicals will raise hell with most of the materials in time.The mfgs are and have been working hard to get maximum life out of their product,Some are better than others.Look around,get some ideas and see who can/will take care of you "locally".Good luck,T.C.

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    Rescue101, I know that there are different grades of stainless out there but that is about it. For us not in the know what are the different grades and which holds up the best. Thanks.
    IACOJ - Senior Jake

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    Default Stainless Steel

    Stainless steel is essentially a low carbon steel which contains chromium at 10% or more by weight. It is this addition of chromium that gives the steel its unique stainless, corrosion resisting properties. The chromium content of the steel allows the formation of a tough, adherent, invisible, corrosion-resisting chromium oxide film on the steel surface. If damaged mechanically or chemically, this film is self-healing provided that oxygen, even in very small amounts is present. The corrosion resistance and other useful properties of the steel are enhanced by increased chromium content and the addition of other contents such as molybdenum, nickel and nitrogen. There are more than 60 grades of stainless steel. However, the entire group can be divided into five classes. Each is identified by the alloying elements which affect their microstructure and for which each is named.

    Why is Stainless Steel Stainless? Because stainless steel contains chromium, it produces a chromium rich oxide film on the surface. While this extremely thin film is invisible to the naked eye, it is in fact not porous and prevents the stainless steel surface from reacting with the atmosphere. The film allows the natural brightness of stainless steel to shine through but, if minor scratches occur, it has the ability to self-heal and return to its initial state almost instantaneously. This film protection is why stainless steel is one of the most hygienic and durable materials available.

    GRADES/APPLICATIONS OF STAINELSS STEEL

    400 Series Martensitic – Typical grade: 410Straight chromium (12-18%), magnetic and can be hardened by heat treatment. Typical uses: Fasteners, pump shafts.
    400 Series Ferritic – Typical grade: 430Straight chromium (12-18%), “low” carbon, magnetic, but not heat treatable. Typical use: Appliance trim, cooking utensils.
    200/300 Series Austenitic – Typical grade: 304
    Chromium (17-25%)/Nickel (8-25%), non-magnetic, non heat treatable. Can develop high strength by cold work. Additions of molybdenum (up to 7%) can increase corrosion resistance. Typical use: Food equipment, chemical equipment, architectural applications and fire apparatus.
    Precipitation Hardening – Typical grade: 17-4Chromium (12-28%)/Nickel (3-9%), Martensitic or austenitic. Develop strength by precipitation hardening reaction during heat treatment. Typical uses: Valves, gears, petro chemical equipment.
    Duplex – Typical grade: 2205Chromium (18-25%)/Nickel (4-7%) and up to 4% molybdenum. More resistance to stress corrosion cracking than austenitic, yet tougher than fully Ferritic alloys. Typical use: Pipelines, pressure vessels, shafting.

    BENEFITS OF STAINLESS STEEL

    Corrosion resistance ---- lower alloyed grades resist corrosion in atmosphere and pure water environments, while high-alloyed grades can resist corrosion in most acids, alkaline solutions, and chlorine bearing environments, properties which are utilized in processing plants.

    Fire & heat resistance ---- special high chromium and nickel-alloyed grades resist scaling and retain strength at high temperatures.

    Aesthetic appearance---- the bright, easily maintained surface of stainless steel provides a modern and attractive appearance.

    Strength-to-weight advantage---- the work-hardening property of austenitic grades, that results in a significant strengthening of the material from cold working alone allow reduced material thickness over conventional grades, therefore cost savings.

    Ease of fabrication---- modern steel-making techniques mean that stainless can be cut, formed, machined, and fabricated as readily as traditional steels.

    Impact resistance---- the austenitic microstructure of the 300 series provides high toughness, from elevated temperatures to far below freezing, making these steels suited to cryogenic applications.

    Long term value---- when the total life cycle costs are considered, stainless is often the least expensive material option.
    Last edited by tomwnh; 03-28-2007 at 07:45 PM.

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    Sshank,Along with what Tomcat said(and I'm NO authority on Stainless)is the process and fasteners used to assemble it.Use the wrong welding wire,it breaks.Use the wrong welding wire,it WILL rust.Now the people that work with this stuff regularly know this.Just know that yoiu need to also know a little bit about it to aid your speccing/bidding process.For that,I'm not your guy.All our rigs with the exception of three are aluminum.Tom is being a bit stingy on info,however if you pressure him a bit it is possible to expand your horizons.He's been around the trade long enough to separate the wheat from the chaff and worked for(or thrown out of)enough Fire apparatus builders to have a unique perspective on things.Fortunately for you,he currently represents a respectable SS builder and a damn good service facility. T.C.

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    Default Stainless Steel

    Stainless steel is very brittle. I does not flex very well either. Truck bodies constantly flex as the apparatus goes down the road. When this occurs with SS, the material will crack instead of bending slightly. Stainless steel bodies are also very difficult to coat with paint. A few departments near us have SS pumper bodies that they have been fighting with the mfg to get repainted. I would recommend aluminum. It has flexible properties, holds paint well and should give you a good 20 years of service without problems. A carbon steel subframe will provide the strength needed to hold all your heavy equipment in the compartments.

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    captain7: you need to go to a local college that has a class on metalurgy. Stainless steel is NOT brittle. It actually will flex and return to its original position better than steel or aluminum. I believe the term is brinnell, which has to do with hardness and flexibility of metal. I was looking for an article I have that was written by a metalurgist, but can't seem to find it right now. But I do know there is a lot of information out there that will refute your statement.

    Each material has distinct advantages and disadvantages, you just need to do your homework to find what fits best for your particular application.

    Another consideration is dis-similar metals between the frame and body, you need to ensure electrolisis won't become an issue.

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    Default Stainless Steel

    You may want to explore Seagrave, they are using a new grade of stainless, which is easier to paint and perform needed bodywork. I dont know the particulars, but they are touting it big time. The cost is more in line with aluminum (which was not meant to build fire apparatus with).

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    From what I hear, the price of Stainless Steel is increasing rapidly and seems to keep going which will drastically increase the price of the truck.

    Something to keep in mind....

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    Default Stainless Cracks!

    When I hear statements that are so blatantly false or are opinion not back by fact I have to respond so I apologize in advance if I ruffle some feathers here or sound like I am taking captian7 to task.

    So stainless cracks. I would love to see the metallurgical test results, done by an independent laboratory, that proves that. Which grade of the more than 150 grades of stainless are you talking about? Depending on the alloy content of any metal, stainless, aluminum or low carbon steel it will have many varying properties. Britle or soft, good corrosion resestance or poor, easy to weld or not……

    As far as painting stainless, no problem, stainless products get painted daily. I have seen paint flake and peal off aluminum and steel bodied trucks. It’s usually a prep problem, not the material the paint is being applied to. One nice feature of stainless is that if it is produced properly you don’t have to paint it. The company I work for does more unpainted bodies than painted. Try that with your aluminum bodies.

    Let’s look at some other applications that use stainless; milk tankers, both straight truck and trailer, yup lots of those on the highway cracked in half. Water haulers, there again in straight truck and tanker trailers, guess they don’t flex that much otherwise we’d see them leaking all over the place. Sanders that are used by highway departments and DOT’s all over the country in winter. I wonder why they are made of stainless now rather than painted steel as in the past. How about cutlery and kitchenware. Have you ever flexed a knife while using it? Did it crack? Maybe you have a stainless steel kitchen sink, what kind of beating does that take year after year?

    Off the top of my head I can think of the following manufacturers that build bodies out of stainless; HME Ahrens Fox, ALF, Seagrave, Pierce, 4 Guys, Saulsbury (now E-One), RD Murray, KME, Ferrara, Crimson, Marion, Toyne, Rosenbauer (Central & General) and Sutphen. I know there are more but that’s the short list. I wonder if they know that stainless cracks. One of the most demanding departments in the world is FDNY. Wonder why their last bid for 69 pumpers was for all stainless bodies?

    And aluminum being flexible. I have witnessed many cracked aluminum bodies over the years. Mostly at weld points but given enough flex any material will crack, especially if it was not manufactured properly. Same with paint. I have seen instances where paint has flaked off aluminum, mild steel and yes, even stainless steel bodies but as mentioned prior, usually a prep problem.

    Let’s try to keep to facts, not opinions and statements not backed by fact to advance an agenda.

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    Thumbs up Stainless steel.

    Draftmaster30,
    I own a machining and welding shop that my father started in '78 and have worked with stainless in numerous applications over the years. In my opinion stainless is the ONLY metal to use to build a fire truck. As stated before in other replies it is not brittle and it is very easy to weld and paint. Go to www.4guysfire.com and click on "why stainless steel?" and you will see for yourself. Our new engine is in the photo archive under custom pumpers, click on Limestone. I designed this and our specs stated all stainless-body, subframe, and wheel well lines. Do not let anyone sell you or your committee on aluminum or steel, if they don't bid all stainless then throw the bid in the trash can.

    As far as the promlem with the department in Connecticut with the HME problems I have never heard of this. If you looked at our engine you will notice that it is HME also but of course the body is 4 Guys. I would have preferred a Spartan chassis but this is only my opinion because I like their interior better. I might even have a copy of our bid specs at home, if they would be any help I would be happy to forward them to you.

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    I've read all the diatribe about the stainless vs aluminum argument. Most all points were very interesting and after reading them all, i must ask: if stainless bodies are the do all, end all, why are the vast majority of custom fire apparatus cabs made of aluminum, not stainless steel? If its the absolute best for bodies, why isnt it for cabs? Let the next round by the sales reps on here begin.

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    Default Stainless debate

    Good luck getting your stainless steel custom mixed by a truck mfg. Your not baking a cake, book boy! Your building a fire truck. You can build your truck out of 316 SS, and have the welder not be warmed-up, or the paint shop not prep the surface properly and still end-up with a junk body. Same with aluminum and cs. By the way bookie, I spent 12 years in mechanical engineering doing nuclear grade ss piping design and nuclear grade heat exchangers, so get over yourself. This material selection argument will get you about as far as who should build it will. Just pick a mfg with a good reputation, talk with other departments around you, and make your selection. BTW, the stainless rescues in FDNY are made of SS, and they are falling apart. Is that because they are constucted of a certain material? Probably not. Will the new piece you are engineering run 30 calls a day? Probably not. Is specing our new truck in SS which could cost 15 - 20% more than alum, worth it, or should you put your truck budget money in something like a light tower, ac, etc. That's for you to decide. When a salemen tells me they do as good of a job on my 1/2 million truck in ss as some other material. I do my homework and pay attention.

    Good day, metal men : ) Har!

    Here's the last piece I designed:
    http://deepwaterfd.photosite.com/
    Last edited by captain7; 04-01-2007 at 05:48 PM.

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    Default Question

    One question Captain7. If stainless is such a terrible material why was it used in your nuclear power plants that have much more critical demands than a fire truck body?

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    Default The end of this thread

    Arguing over body material type from and engineering standpoint on this forum does not benefit the original guy's posted question. So I give. Uncle already.

    Stay Safe!
    Mark

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    Do your homework,Eh? If you had,you would have caught a glimmer in my response to clue you in to the fact that Tomcat has worked in truck shops and apparatus builders longer than you've played with Nuke plants,which for what it's worth,have vastly different material types and needs(ss)than a body builder.For the record,our apparatus are, for the most part,aluminum although it's far from a perfect building material. For what we do,and how we do it,and the service life expected it's adequate.SS has been used in truck body construction for years with good success.So obviously there are a few builders out there who know how to do it.As far as paint goes,it's all in the prep just like any other material.Try painting galvy sometime.You like aluminum? Great! But to suggest it's the ONLY material is ludicrous.How about poly? Not for everyone but it won't rust. T.C.

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    Default No need to give!

    Hi T.C. heard it was snowing up your way today. Not down here, just rain but told it's comming.

    captain7, there is no need to "give". We were having a civil discussion I thought. Exchange of opinions and views. As long as it stays civil that's how we learn. Hell, I'm am not by any means the sharpest knife in the draw. I learn everyday. I even have my opinions changed every now and then but that is hard being the pig headed Yankee I am.

    As far as the questions draftmaster asked, we have emailed each other and I have sent him info, from 3rd party sourses, to assist him in his quest for knowledge.

    And when it comes selection of body material, colors, engines, doors, pumps etc, etc etc...... I have found most times opinion and emotion win over facts. We all have prefeances. Life, go figure.

    Stay safe

    Tom (or Tomcat as TC calls me)

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    Default aluminum vs s/s body

    Does anyone presently have an aluminum body pumper and now would say " Wow, what a mistake. Next time the body will be made out of__________". If so who was your manufacturer and what are the problems. thanks

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    Thumbs up

    I saw the Crimson Vibra Torque system you speak of Draftmaster. It looks great actually. Some other mfg’s have used systems in which the body and frame are isolated only by flat rubber mounting pads – and then they bolt straight down to the frame (essentially).

    No matter what material the body is (provided it is welded properly) the "Vibra Torque system" will aid immensely in keeping the body and subframe from cracking up. The body will still do some flexing but a system like the Vibra Torque will keep road vibrations down.

    With that said – stainless or aluminum? I am no expert on bodies but I would say that “Captain7” ‘s comments might have been his experience with a particular body in which the material was overheated during welding – or welded with the wrong wire (electrode). That might explain why he experienced cracking in an otherwise ductile material. TL
    Last edited by SSIaerialmanTIM; 04-30-2007 at 04:30 PM. Reason: duplicate word

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