Greddy Titanium Exhaust System...

[SpoolinSr20]

Anyone have pic's of it on a 240sx.. There's barely anything for it besides the company picture...
thanks
joe

[IvanAtSPRacing]

Take a look at my thread HERE (http://www.zilvia.net/f/showthread.php?t=65666&highlight=bogarts) and there are a few pictures of the Greddy Ti installed on the car.

[PinkPanther]

Whoa, is that joey feng's R34 in the stall next to your drag car? :mepoke:

[SpoolinSr20]

Ivan is that the new greddy titanium exhaust? the one around $800.00
Is that the angle it comes in or did you bend it for the jdm look?
thanks
joe

[KoukiMonster]

i know what titanium is...but why spend so much on an exhaust. is this a show car?


if not... i suggest custom.

[akablingdawg]

here mine
http://www.imagestation.com/picture/sraid150/pb6d73392f7d25a9499ada902de399a47/f5d6448f.jpg

http://www.imagestation.com/picture/sraid150/p3837ee0d9352cb5430ce3b1b49ef1dca/f5d644a3.jpg

http://www.imagestation.com/picture/sraid150/p2d8db7615ab29a8d79b34327f3441dc0/f5d64ff2.jpg

[S14DB]

I swear this thing is louder than a straight pipe. Looks hawt thou.

[FRpilot]

i know what titanium is...but why spend so much on an exhaust. is this a show car?


if not... i suggest custom.

not so much as for show.. titanium is oftened seeked out and cherished by hardcore weight saving freaks like myself. titanium characteristics offer superior strength while being extremly light which is what makes it so great. titanium is similar to the magnesium that is used in volk and other wheels where the strength threshold is so great that less of the material can be used to forge a wheel that has the same strength as the original metal used to forge the wheel yet lighter since less magnesium is used in creating the wheel. unlike cheap people, serious racers will pay for the quality and characteristics of a titanium exhaust.

[PinkPanther]

Plus it makes pretty colors when you heat it up. :mepoke:

[akablingdawg]

that baby is 10 lbs also

[IvanAtSPRacing]

Ivan is that the new greddy titanium exhaust? the one around $800.00
Is that the angle it comes in or did you bend it for the jdm look?
thanks
joe

I didnt know that Greddy had an 'old" Ti exhaust. This one is only months old. And this is the way it sits on my car. Its not bent.

[IvanAtSPRacing]

i know what titanium is...but why spend so much on an exhaust. is this a show car?


if not... i suggest custom.


Not really a show car, its a race car that is being done right and should look good. Because we are the oldest Greddy dealer in the mid west, I get a pretty steep discount so it wasnt all that expensive. The entire exhaust weighs 11 lbs versus the stock 40 lbs. Weight savings is important to me. The 3" straight thru design is awesome and will offer as little restriction as possible.

[SpoolinSr20]

akablingdawg,
Do you have a picture behind the car?
thanks
joe

[akablingdawg]

here no to clean
http://www.imagestation.com/picture/sraid150/pa82d19bd9c058bc67707645af639013a/f5d4b698.jpg

[axiomatik]

...titanium is similar to the magnesium that is used in volk and other wheels where the strength threshold is so great that less of the material can be used to forge a wheel that has the same strength as the original metal used to forge the wheel yet lighter since less magnesium is used in creating the wheel....

You're close, but not quite right. Magnesium is actually not as strong as aluminum, but it is substantially lighter (the density is about 40% less). That is why when you see genuine 'mag' wheels ('mag' being short for magnesium), they have pretty beefy designs. Because magnesium isn't as strong as aluminum, more material is required to get the same strength, but because magnesium is substantially less dense, the resulting wheel is actually lighter than an aluminum one.

Titanium is pretty strong, but not like those stupid Remington Shaver commercials would lead you to believe. It's main benefit is that it is a very light material, offering strength comparable to steel, but substantially lighter (about 40% lighter than steel).

[SpoolinSr20]

Anyone have a pic of this exhaust on a s13?
:)

[internetaardvark]

You're close, but not quite right. Magnesium is actually not as strong as aluminum, but it is substantially lighter (the density is about 40% less). That is why when you see genuine 'mag' wheels ('mag' being short for magnesium), they have pretty beefy designs. Because magnesium isn't as strong as aluminum, more material is required to get the same strength, but because magnesium is substantially less dense, the resulting wheel is actually lighter than an aluminum one.

Titanium is pretty strong, but not like those stupid Remington Shaver commercials would lead you to believe. It's main benefit is that it is a very light material, offering strength comparable to steel, but substantially lighter (about 40% lighter than steel).


Actually sorry but your wrong. Titanium is extremely strong, in fact its much stronger than stainless steel, which in turn is much stronger than mild steel. Sorry dude but I'm a machinist and the last place that I worked at made giant chemical seperations solutions for oil refineries and the like. I didn't even see a single piece of mild steel the entire time I worked there. But I saw/worked with alot of titanium, and believe me its strong. Another thing that most people don't know about titanium is that it is heat treatable, it can be hardened and tempered etc. The only reason that titanium isn't used more often in industry is because it is so expensive, and like all metals its price is a direct correlation to its rarity. Make no mistake titanium is very light, but it is also very strong as well. The only downside if any to titanium is that due to its stiffness it is more likely to snap rather than it is to bend. So if any of you ever buy a titanium exhaust do your selves a favor take extremely good care of it and what ever you do don't ever try to bend or flex it.


On e more thing before I go I'm gonna be buying one of those exhaust myself, it said on the greddy web site that some modification to the frame may be necessary for use. Is this in fact the case? If so what am I in for?
Thanks guys.

[XxJaPxOxNeEs23xX]

im interesetd in buying. and one u guys said its louder than strait pipe. is that louder than the apex n1s??

[SlowCoupe]

i have the uras 3in catback...its basically a straight pipe back with a so called muffler at the exit end...its pretty loud...i would say its comparable to the Greddy shown above except its a lil heavier than the greddy...louder than the apexi's

[projectRDM]

i have the uras 3in catback...its basically a straight pipe back with a so called muffler at the exit end...its pretty loud...i would say its comparable to the Greddy shown above except its a lil heavier than the greddy...louder than the apexi's


It's much louder. Titanium exhausts are thin as hell, and resonate much differently.

[Ian]

ah, so since titanium is so stiff, is that why when you see Ti intercooler piping on show cars and high dollar race cars, it's sectioned ever inch or so instead of bent?...it all makes sense now

[internetaardvark]

ah, so since titanium is so stiff, is that why when you see Ti intercooler piping on show cars and high dollar race cars, it's sectioned ever inch or so instead of bent?...it all makes sense now


You got it, that is exactly why you see that. Also if you notice on the greddy ti; http://www.imagestation.com/picture/sraid150/p3837ee0d9352cb5430ce3b1b49ef1dca/f5d644a3.jpg (hope you don't mind that I used your pic akablingdawg)
If you look at the hangers, you notice that they are attached by a strap of stainless steel. They had to do that because titanium doesn't really like to be welded to other metals, it "can" be done, but its not that reliable. And obviously they cant easily make those hangers out of ti, so instead they make them out of stainles and attach them with a strap. I hope I'm not coming off sounding like a know it all, its just that I seldom get a chance to discuss the properties of metals with people that are even semi interested:hs:
And yes I know... Im a geek. :bow:

[nutipah]

how would you compare the sound quality versus most other exhausts? I have an N1 dual right now, but I'm bored with it...The deep only sound gets old. I'm guessing this pipe would sound more tinny at high rpms, right? Which I like...I am leaning towards custom tho...just a straight pipe...it's not my daily so I don't care if it's too loud.

[XxJaPxOxNeEs23xX]

yeh can we get a sound clip of this exhasut?? thanks

[Titan]

Actually sorry but your wrong. Titanium is extremely strong, in fact its much stronger than stainless steel, which in turn is much stronger than mild steel. Sorry dude but I'm a machinist and the last place that I worked at made giant chemical seperations solutions for oil refineries and the like.


Actually, not quite.

Commercially pure titanium has an ultimate tensile strength of 275-590 MPa, whereas common 304 Stainless has a typical UTS of 600 MPa. Hardly much stronger then stainless. Of course, many titanium alloys exist that can increase the strength to well over 1250 MPa UTS; much in the same fashion that stainless can be hardened/alloyed in order to increase its strength.

Personally, I think a titanium exhaust is overkill. Same goes for lightweight lugnuts and the like. To me, a custom exhaust from stainless is much more appealing. Not for strength or weight reduction, but for corrosion resistance at a resonable price. Then again, not everyone has their own tig welder. :cool:

[driftstyre]

I'm not going to pretend to know a lot about metals but from what I do know, Titanium and Titanium Alloy like 6AL-4V are much different in strength with the latter being much harder and stronger than pure Ti. Mandrel bending Ti Alloy is supposedly very hard from what I hear. I've cut and welded Ti Alloy and it is not much different than stainless in that respect(it is harder to cut). For exhausts, titanium alloy is not an ideal material for higher temp (1500-2500 F) exhaust systems in motorsport. Inconel is usually used in situations where antilag or post-combustion-systems are present and the majority of modern day racecars for that matter. The wall thickness on most performance exhaust systems is usually .065 but .049 or even .035 can be purchased for not too much more and the weight savings is very surprising, almost like picking up a similar Ti piece.

Also Magnesium is light and used for motorsport and rarely street cars for the reason that it warps over time and has a certain lifecycle in which its tollerences are correct.

[BSeay]

Geeks the lot of you!!....(is offically confused now)

[ZK]

A friend of mine had the HKS Titanium exhaust on his Supra. He took it on Thunderhill road track and went off track into a run off area. We looked under the car after that and the Ti exhaust piping looked like crumpled paper and everything else was fine... not too strong if you ask me.

[axiomatik]

The entire strength discussion is really moot without knowing what alloy is used and what kind of treatment it had, these factors can affect the material strength tenfold. I was speaking in generalities above since I don't know what alloys were used. Many people believe that Titanium is some 'super-metal'. It's not. While it is generally stronger than steel, its real benefit comes from its low density.

[nutipah]

who gives a fcuk what the properties are. What the hell does it sound like? Damn nerds spoutin off bullshit.

[Titan]

who gives a fcuk what the properties are. What the hell does it sound like? Damn nerds spoutin off bullshit.

I once thought like you, then I realized I didn't want a career mixing concrete.

[internetaardvark]

who gives a fcuk what the properties are. What the hell does it sound like? Damn nerds spoutin off bullshit.

:duh: Dude next time you go to open your mouth make sure your under water. So you don't infect us all with your ignorance. One of my favorite quotes has allways been "The day you stop learning is the day you start dieing." Going on that quote you must be pretty much worm food by now. :fawkd:

You wanna know who gives a fuck? People that are interested in thinking for themselves. Silly me I thought you guys might actually give a shit about the actual reasons to go with ti, instead of just being told " yeah it make you mad fast yo! Give you like 30 style points to." I should have known better than to assume that just because this is a nissan forum there wouldn't be honda boys lurking around. :hammer:
And before you rip on me for that, being a honda boy has nothing to do with what kind of car you drive it has to do with your general mindset.
And if you care more about is making your car look or sound a certain way than making it fast, then why don't you just slap i type r emblem on the back of it and then drive it into a tree drag racing a corolla.:drool:

[internetaardvark]

I once thought like you, then I realized I didn't want a career mixing concrete.

Thanks titan I just noticed your reply. I appreciate it.

[RSP13-Sideways]

Please go on about the properties, I'm very interested in the difference as well. Who give's a damn about the "sound", let's find out the large price difference and if/why it's actually worth it?

[internetaardvark]

Geeks the lot of you!!....(is offically confused now)
If your confused ask for clarification obviously nbrindley and acouple of the other guys here know what they are talking about. Ask for clarification now while the topic is still fresh.

[internetaardvark]

Actually, not quite.

Commercially pure titanium has an ultimate tensile strength of 275-590 MPa, whereas common 304 Stainless has a typical UTS of 600 MPa. Hardly much stronger then stainless. Of course, many titanium alloys exist that can increase the strength to well over 1250 MPa UTS; much in the same fashion that stainless can be hardened/alloyed in order to increase its strength.

Personally, I think a titanium exhaust is overkill. Same goes for lightweight lugnuts and the like. To me, a custom exhaust from stainless is much more appealing. Not for strength or weight reduction, but for corrosion resistance at a resonable price. Then again, not everyone has their own tig welder. :cool: No they don't and If i were to have a custom exhaust made by a shop it would be near the cost of starting out with a production ti exhaust. 730 free shipping at hopupracing.com

:confused: Dude titanium is less corrosion prone then stainless. It doesn't oxidize. In fact alot of the more exotic alloys use ti. Inconell uses a large percentage of Ti, as well as nickel. Thats why its so fing hard and resistant to heat.

Actually my statement stands, tensile streangth refers to the amount of force neccessary to snap or tear a given metal. When I said strength i was refering to its ability to hold its shape and properties under load, ie hardness. Generally speaking as hardness goes up, tensile strength goes down, because the harder something is the more brittle it usually is. So my statement of Titanium being harder is still correct as far as I see it. Besides thats what I was talking about when I said it was more likely to snap then bend. What we are now discussing is not really the actuall strength of materials, so much as the properties they display when they fail, ie wether they stretch, snap, shere, etc.

As far as the overkill comment goes I consider it overkill to gut the interior of a street car but some people do it and they do get beter performance as a result. Going from 40lbs stock to 10lbs ti is nothing to sneez at, As far as weight reduction goes thats a pretty big decrese for something as simple as an exhaust.
And besides I never claimed it wasn't overkill. Just that it was the better choice in my opinion regardless of cost. Besides think of what the exhaust system is most closely tied into... the turbo housing. I don't know about you but don't want anything that heavy hanging on my turbo, directly or inderectly.

[internetaardvark]

Please go on about the properties, I'm very interested in the difference as well. Who give's a damn about the "sound", let's find out the large price difference and if/why it's actually worth it?

First off the thing you guys have to realize is with all metals there is a lot more that goes into it than just saying this is stronger. In chemistry the only time they use the term strong is when they are referring to the tensile strength of a material, which is different from the strength that we have been talking about here.

If you guys really want to learn about the different properties of materials try going here. The site is called engineers edge and its an info site for engineering.engineers edge material properties (http://www.engineersedge.com/strength_of_materials.htm)

That should take care of most of the misconceptions here without getting me chewed out by ricers. :bash: If you do have any more specific questions after that I'm more than willing to explain as best I can. ;)

[internetaardvark]

heres another from the same site;
http://www.engineersedge.com/material_manufacturing.htm

[Titan]

:confused: Dude titanium is less corrosion prone then stainless. It doesn't oxidize. In fact alot of the more exotic alloys use ti. Inconell uses a large percentage of Ti, as well as nickel. Thats why its so fing hard and resistant to heat.

Titanium is less corrosive, correct. Although the corrosion resistance of 304 stainless, or any other composition with a decent percentage of chromium, is extremely good. Far beyond what is needed considering the environment of an exhaust.




Actually my statement stands, tensile streangth refers to the amount of force neccessary to snap or tear a given metal. When I said strength i was refering to its ability to hold its shape and properties under load, ie hardness. Generally speaking as hardness goes up, tensile strength goes down, because the harder something is the more brittle it usually is.

Actually, it's the opposite. Tensile strength is directly proportional to hardness. As hardness increases, so does tensile strength, and vice versa. Just because a material is brittle does not mean it is weaker. Take metals that have a martensitic grain structure for instance. Such metals have an incredibly high hardness (370+ HB in some cases), are very brittle (as low as 6% elongation), yet have extremely high tensile strengths.

A material being able to hold it's shape under load is also directly proportional to tensile strength. Sure, a material with a high UTS and low elongation may fail in a brittle fashion, but it will withstand a higher load before failing as opposed to a more ductile material with lower UTS.




As far as the overkill comment goes I consider it overkill to gut the interior of a street car but some people do it and they do get beter performance as a result. Going from 40lbs stock to 10lbs ti is nothing to sneez at, As far as weight reduction goes thats a pretty big decrese for something as simple as an exhaust.


True enough. However, I'm looking at it from a cost/benefit ratio standpoint. Given that extra $300 between a stainless and titanium exhaust, I feel it would be better spent on say an s-afc. Which could net you a few extra hp stock, making up for the extra weight, while also giving you more tuning options in the future should you go with larger injectors, turbo, etc.


I'm not trying to be a dick here. We both have good points, and this is a good discussion. However I must stand on my materials facts, since I'm in the process of becomming a mechanical engineer and have/had to go through many materials courses. NEVER take engineering if you value your social life. :down:

[Advan]

lol, I love Titans comment. Anyways, my question is, what's the whole point in getting a ridiculous loud muffler? Since one of you mentioned Honda, I'd sit outside of Subway waiting to go to work and hear a ridiculous loud sound behind me, only to find a Civic going about 30-35mph. I can understand that getting a performance muffler is a good thing for hp, and torque, but buying a loud bee sound one, is just crossing the line. I will admit, the 240's that I've seen around town didn't have these loud..oh so loud mufflers, but it's always the Hondas. In general, what's the point in getting a loud, loud, muffler? I mean, is it for atention, or performance? I'm still in the learning stages of mufflers and figuring out which one will produce a nice sound, but put out a decent to good amount of performance.

[nutipah]

you guys crack me up...everyone wants to be viewed as "the expert" Hey Lay off the honda guys...Honda's been in F1 for 50 years and one countless times...they are by far the most performance oriented Japanese company :p AND they don't have a monopoly on rice...every car gets riced

[Titan]

...Honda's been in F1 for 50 years and one countless times...

"won"

I think the concrete is getting dry, better check up on it.
:D

[nutipah]

geez, internet fags...can't escape 'em

[SimpleS14]

internetaardvark - Would you like to do some of my Geology and Chemistry homework?

I'M JUST KIDDING :D


But seriously....this thread has some nice information.

[internetaardvark]

you guys crack me up...everyone wants to be viewed as "the expert" Hey Lay off the honda guys...Honda's been in F1 for 50 years and one countless times...they are by far the most performance oriented Japanese company :p AND they don't have a monopoly on rice...every car gets riced

:duh: :duh:
Dude how old are you Ive met 5 yr olds quicker on the uptake than you! Did you even bother to read/think about my post before trying to look like a big man. Cause you whould have realized that you just repeated my main point.

"And before you rip on me for that, being a honda boy has nothing to do with what kind of car you drive it has to do with your general mindset.
And if you care more about is making your car look or sound a certain way than making it fast, then why don't you just slap i type r emblem on the back of it and then drive it into a tree drag racing a corolla."

And you know all your doing with your weak ass comments, is backing up that statement.
Try thinking before posting next time. For that matter just try thinking! :mepoke:

[internetaardvark]

internetaardvark - Would you like to do some of my Geology and Chemistry homework?

I'M JUST KIDDING :D


But seriously....this thread has some nice information.

Actually I loved chemistry so much that at the end of the year, my HS-teacher gave me one of the textbooks you know the 100 dollar ones.

As far as titans comments go I appologize if I mistated anything, and if I did then I don't view you correcting me as being a dick. I view it as a helping hand. After all if no one corrects me when I say something dumb, how am I suposed to know its dumb.
Like I said its been a while since I've been able to talk properties, some of my terminology may be rusty. In the post about titanium being strong I was mainly speaking from my experiences machining it. Which as I said I did alot of. And no It wasn't an alloy. And I also worked with hastalloy, inconel, and tons of different kinds of stainless steels.

[internetaardvark]

lol, I love Titans comment. Anyways, my question is, what's the whole point in getting a ridiculous loud muffler? Since one of you mentioned Honda, I'd sit outside of Subway waiting to go to work and hear a ridiculous loud sound behind me, only to find a Civic going about 30-35mph. I can understand that getting a performance muffler is a good thing for hp, and torque, but buying a loud bee sound one, is just crossing the line. I will admit, the 240's that I've seen around town didn't have these loud..oh so loud mufflers, but it's always the Hondas. In general, what's the point in getting a loud, loud, muffler? I mean, is it for atention, or performance? I'm still in the learning stages of mufflers and figuring out which one will produce a nice sound, but put out a decent to good amount of performance.

High noise comes with high flow its an unfortunate side affect thats why straight pipes, and for that mater 3in diameter ti exhausts are loud as hell. And that bumble bee noise you heard, resuslts from removing the cat and haveing nothing to muffle the sound of the tiny engine.

Big exhaust generally flow better and have less back pressure so they are good for turbos. They also are much louder. There fore if its good for your car chances are its louder than a mofo!
Na's don't need as big exhausts though, because you don't have to worry so much about back pressure.

[Gladman]

I plan on doing my own Ti exhaust, im probably goin to just use a section of 3" pipe with 1 or 2 hangers. Purely for weight savings, no muffler etc. Im hoping to get 1 or 2 30-40 degree bends in the pipe with a mandrel bender without tearing or crinkleing the pipe.

From what i've heard Ti is half the weight of regular exhaust tubing with the same strength. So basically same diameter pipe, same wall thickness, half the weight.

I've run a 3" straight pipe before, and it wasnt that loud, but having a turbo 6" from your head does a lot for noise.

[internetaardvark]

dude are you THE gladman the one that makes exhaust manis for the s13 SOHC? Nice to meet you! Tasty ratz showed me a clip of you once, it was quite fun to watch. :bigok: Tasty has an Attain full titanium 3in cat back on his s13 sohc right now, before we put it on he had me lift it and it must have weighed like 7lbs, don't quote me on that as i didn't actually weigh it, Titanium is amazingly light, given the strength it has.

And Titan I concede your right like I said I'm kinda rusty. What I was thinking of was shock resistance, Ie resistance to drop kicks/hammer blows. I had no Idea that titanium was weaker than steel though, like I said I worked with it a lot and it was a lot stiffer than the stainless steel I had worked with, and Ive worked with allot of stainless grades. Sorry for the missinformation, but I still see Titanium as a worth while investment. I understand where your coming from, but at the same time increasing your horsepower wont help you stop quicker or turn a corner easier/faster, which is not totally but mostly dependant on your mass and resulting inertia. And while acceleration can be increased by adding hp. the only way to lower inertia is thru weight reduction. That is mainly why I see titanium as such a good material. Btw do you have any specs on the tensile strength of titanium once its been hardened? I know I've watched work hardened titanium shatter solid carbide end mills more than a few times.

Also I still havent heard any responses about wether I'll need to trim any thing to get the exhaust to fit.

[Zen S14]

How much louder is louder?

I have a single pipe Apexi N1 with the resonator removed and it is rumbly. However, I would not say it is unbearable.

I am definitely looking into the "Greedy" Ti for weight and show enchancement. However, I am concerned about loudness relative to the current setup.

[Titan]

Its strength compaired to steel is suprising, yes, however that is pure titanium. When it is alloyed with various other metals, the mechanical properties can be incredible.

I'll have to look up the hardness of heat treated titanium. Although I think pure titanium is rare in construction; I'd imagine most would be some sort of alloy.

[Inland180]

Nice ass exhaust system!!! :hsdance:

[boosted_240]

Anyone have pics of this from the rear of the car?

[internetaardvark]

Its strength compaired to steel is suprising, yes, however that is pure titanium. When it is alloyed with various other metals, the mechanical properties can be incredible.

I'll have to look up the hardness of heat treated titanium. Although I think pure titanium is rare in construction; I'd imagine most would be some sort of alloy.

Like I said titanium is significantly more expensive/rare, than steel and other metals, so I can't see people using it in an application like construction, where large amounts of it are going to be necessary. If you look at the aerospace industry however, you would find that they use it quite extensively. Another feild that you see using titanium is the medical industry. Both of these feilds have applications which require parts to have very specific characteristics regardless of cost. Which to some extent is how I feel, I plan on having my car for quite a while so I don't mind saving up a little longer for better parts. Thats the way I look at it.

Anyone have pics of this from the rear of the car?

Check page one.

[RBS14]

another thing I don't think was mentioned was that Ti is also a very flexible metal. Very good memory, springs back to it's original shape when stressed within it's limits.

[internetaardvark]

another thing I don't think was mentioned was that Ti is also a very flexible metal. Very good memory, springs back to it's original shape when stressed within it's limits.


Key words there being within its limits. BTW the technical term for that is "Elastic Limit". And like I said it can be heat treated, ie hardened/tempered just like steel can, which is what causes that springy phenomenon.

[RBS14]

I just know that Titanium bicycles are a ton of fun to ride because of the springyness they have, as compared to aluminum, steel, carbon etc.

[Gladman]

Titanium makes sweet looking sparks when you bottom out :D

[Gladman]

another thing I don't think was mentioned was that Ti is also a very flexible metal. Very good memory, springs back to it's original shape when stressed within it's limits.

That shouldnt even be an issue in an exhaust unless you skimp out on hangers, a 5lb exhaust pipe wont move around very much at all.

[internetaardvark]

I just know that Titanium bicycles are a ton of fun to ride because of the springyness they have, as compared to aluminum, steel, carbon etc.

Key words there being within its limits. BTW the technical term for that is "Elastic Limit". And like I said it can be heat treated, ie hardened/tempered just like steel can, which is what causes that springy phenomenon.

Sorry dude I don't think I was clear in my response, I wasn't correcting you I was agreeing with you. And also i meant to say, heat treating can "Add" to the springy properties of a metal. But you were correct titanium has excellent memory. The point i had tried to make in some of my earlier posts though was that like most springy metals/alloys, once titanium reaches its elastic limit, instead of twisting crumpleing or warping the way mild steel would, Ti will just snap. Its similar in that respect to spring steel.

[RBS14]

cool.

I didn't know that much so thanks for posting more info about it.

[Titan]

The point i had tried to make in some of my earlier posts though was that like most springy metals/alloys, once titanium reaches its elastic limit, instead of twisting crumpleing or warping the way mild steel would, Ti will just snap. Its similar in that respect to spring steel.

Not quite. If you look at the stress vs. strain curve of titanium, you will notice it has a plastic region.

The "memory" mentioned is called the elastic region, as you stated earlier. You can apply force in this region, and have the material return to its original shape.

However, if you exceed this force, the material will enter the plastic region and be permanently elongated. The point where this begins is called the yield point.

Applying more force, the material will reach UTS (Ultimate Tensile Strength), then eventually fall off and fail.

Here is an example:

http://www.tpub.com/content/doe/h1017v1/img/h1017v1_69_5.jpg


For grade 2 titanium, you are looking at a yield of about 275 MPa, and a UTS of about 345. So infact, you can have an extra 70 MPa of pressure acting on the material beyond the elastic region before you even hit UTS. In other words, you CAN elongate titanium beyond the elastic region without it snapping.

[internetaardvark]

Not quite. If you look at the stress vs. strain curve of titanium, you will notice it has a plastic region.

The "memory" mentioned is called the elastic region, as you stated earlier. You can apply force in this region, and have the material return to its original shape.

However, if you exceed this force, the material will enter the plastic region and be permanently elongated. The point where this begins is called the yield point.

Applying more force, the material will reach UTS (Ultimate Tensile Strength), then eventually fall off and fail...

Yes that would have to be the case otherwise it wouldn't be hard to bend ti it would be imposible obviously there has to be some sort of plastic region present other wise it would be next to imposible to cold form. I wasn't trying to say it would snap imediately afer the elastic region. I was trying to say that when compared to mild steel and even stainless it has a much shorter plastic region. I appologize I should have been more clear. Do you have, or can you make another one of those fancy graphs for steel so that we have something to compare the ti one to? Sorry to ask this, but it's become blatantly obvious that you know more about this than I do, so I'm not trying to corect you or prove you wrong or any thing I'm just trying to figure out the science behind what I have witnessed many times first hand. Thanks again for the correction, and I'm looking forward to many more from you. ;)

[TurDz]

referenced from here:

http://www.yourencyclopedia.net/tensile_strength.html

Some typical tensile strengths of some materials:

Material / Yield strength(MPa) / Ultimate strength(MPa)
Structural Steel ASTM-A36 / 250 / 400
Steel High strengh alloy ASTM A-514 / 690 / 760
Stainless Steel AISI 302 - Cold-rolled / 520 / 860
Titanium Alloy (6% Al, 4% V) / 830 / 900

It's true that both have some room to "stretch" after hitting the yield point, but the great thing about steel (cold-rolled) is it's characteristics AFTER yielding. See how it can sustain about 300+ MPa more stress after yield point? While the above type of titanium alloy has an extremely high yielding value, it only take a 70MPa of stress to reach UTS.

Since steel is so much cheaper, it is still widely used. It's characteristics of having 300MPa of plastic region is important because under inspecting, you can easily tell when it reached yield point but still safely stay under the UTS. While as for Ti alloy, it may be more risky since it can actually hit UTS and fail before you know it.

On the other side, Ti alloy is just crazy with it's 830MPa yield. It's almost as high as cold-rolled steel's UTS :)

hi engineers :cool:

[internetaardvark]

... On the other side, Ti alloy is just crazy with it's 830MPa yield. It's almost as high as cold-rolled steel's UTS :)

hi engineers :cool:


Thanks dude.

[Titan]

Mind you that is titanium alloyed with aluminum and vanadium. I was referring to commercially pure Ti.

You are correct, yes; the plastic region is much greater for steel then titanium. However, this greater differential between yield and UTS is not desirable. For most forms of construction/machine components, once the part has reached yield, it is considered to have failed.

Consider two connecting rods, created from stainless steel and titanium respectively. Both rods are subjected to a tensile force of 700 Mpa. Assume elastic elongation to be negligible. The titanium rod will operate within its elastic limit, and likewise maintain proper rod length. The steel rod however, will yield and elongate, effectively lengthening stroke and failing in its duty.

For this reason, in most cases, titanium would be far more desirable then steel. However, cost is the leading factor as you mentioned.

This applies to just about any form of machine component or structural member. Each part is always engineered to operate below yield, and can never be considered safe when operating between yield and UTS. Certain exceptions do exist, such as our torque-to-yield head bolts, but in nearly all cases my above statement holds.

[TurDz]

Maybe we should not even compare Ti alloys to Steel then. Generally they have different characteristics. Titanium is far better just because it has a higher yield, but Steel is superior to most other metals both strength and cost wise.

[Titan]

Yes that would have to be the case otherwise it wouldn't be hard to bend ti it would be imposible obviously there has to be some sort of plastic region present other wise it would be next to imposible to cold form. I wasn't trying to say it would snap imediately afer the elastic region. I was trying to say that when compared to mild steel and even stainless it has a much shorter plastic region.


Exactly. You're right, it does have a much shorter plastic region. I just misinterpreted what you said. As for the graphs, that particular one I posted was just a generic example of a stress-strain curve. I'll look up some specific to titanium and steel and post them as I find them.



Maybe we should not even compare Ti alloys to Steel then. Generally they have different characteristics. Titanium is far better just because it has a higher yield, but Steel is superior to most other metals both strength and cost wise.

Very true. In an ideal world, titanium would be used as a substitute for steel in many situations. However, like you said, cost is a big factor. The best material depends on the application/budget.

[internetaardvark]

Exactly. You're right, it does have a much shorter plastic region. I just misinterpreted what you said. As for the graphs, that particular one I posted was just a generic example of a stress-strain curve. I'll look up some specific to titanium and steel and post them as I find them.


Very true. In an ideal world, titanium would be used as a substitute for steel in many situations. However, like you said, cost is a big factor. The best material depends on the application/budget.
I just read this and realized how hilarious these past few exchanges were...
this is the kind of thing (this arguement) that develops between machinists that have worked with the metal firsthand and have at least some semblance of metalurgy knowledge but it's all self taught, and mechanical engineers that have a degree in the subject, but have never worked with the metal. No, don't even think of taking this as a personal attack. This really did just strike me as hilarious. I can't tell you how many times I went in to talk to the me's at my last job because there was info missing on a print that everyone in the company had been using for over a year, so when i say this is what happens I'm speaking from personal experience. However I must say I'm somewhat disapointed that you proceeded to "correct me" on a post were I was simply trying to explain where I was coming from. And btw adding aluminum to titanium would if anything add to its machinability and forming ability It would not add to its strength and certainly not decrease its elastic region, aluminum is much more maleable than ti, so I don't know where you are going with that one. If what I said about Titanium is correct to begin with why did you feel the need to correct me?
Very true. In an ideal world, titanium would be used as a substitute for steel in many situations. However, like you said, cost is a big factor. The best material depends on the application/budget
Sorry but I dissagree with you there. I said that cost was a reason that ti isnt used more often, that doesn't make steel better it makes it cheaper. Some parts are required to have the same strength right up to the yeild point, this is especially true of close tolerence moving parts(anything in an engine), because as you your self said once the yeild point is reached the part is considered to have failed. so going on that if steel yeilds at a lower level than titanium then titanium will efectively have a higher strength because it can take more force before it yields You should be more careful how you fraise things. Obviously you and I know what we are talking about, but if I had come here and read your posts, with none of the material knowledge that I have, then I would have thought that you were trying to say that; even if ti were cheaper then steel, it still wouldn't be used because it is inferior. Oh and just a little piece of freindly advice; when you graduate and begin working in the industry, do your self a favor and make sure you consider any input that is brought up by a machinist. It's easy to figure out who knows their stuff and who doesn't but it's much harder to get input/advice when you have a reputation for stonewalling people. Believe me I've watched people get laid off for that kind of thing. Oh and also never stop learning! :bigok:

[Titan]

However I must say I'm somewhat disapointed that you proceeded to "correct me" on a post were I was simply trying to explain where I was coming from. And btw adding aluminum to titanium would if anything add to its machinability and forming ability It would not add to its strength and certainly not decrease its elastic region, aluminum is much more maleable than ti, so I don't know where you are going with that one. If what I said about Titanium is correct to begin with why did you feel the need to correct me?


That's where you are wrong. Adding aluminum DOES increase strength. Believe it or not, alloying materials can result in a material of HIGHER strength then either of the pure metals. It all has to do with the grain structure of the alloy relating to the distortion of crystal planes that, in turn, resist dislocations.

Take this for example:

Pure Copper Yield = 70 MPa
Pure Aluminum Yield = 35 MPa
Pure Nickel Yield = 110 MPA

Now look at the alloys of these materials:

Copper - 5% Aluminum Yield = 125 MPa
Copper - 70% Nickel Yield = 270 MPa

I felt the need to correct you because, as I mentioned in my first post, pure titanium is still weaker then steel. All my information is accurate, you can confirm it any material text. Do not take this the wrong way; this is not a personal attack. I am merely defending my original point.



You should be more careful how you fraise things obviously you and I know what we are talking about but if I had come here and read your posts, with none of the material knowledge that I have, then I would have thought that you were trying to say that even if ti were cheaper then steel it still wouldn't be used because it is inferior.

Pure titanium would be inferior to steel from a strength point of view, yes. Keyword here is "pure". As I mentioned above and in previous posts, alloying titanium can increase its strength dramatically.



Oh and just a little piece of freindly advice; when you graduate and begin working in the industry,

I am on coop. I work in the industry every alternate 4 months, for a duration of 4 months. Not much experience, true, but I am not entirely naive.



do your self a favor and make sure you consider any input that is brought up by a machinist. It's easy to figure out who knows their stuff and who doesn't but it's much harder to get input/advice when you have a reputation for stonewalling people.

On every work term of mine, I have always taken the machinists' opinion over any engineers'. There is no denying it, for the majority of the time, practical experience will always conquer theory. Having realized this many years ago, I am not an egghead. I work on mills and lathes frequently. I am a TIG welder by hobby and am also in the process of taking additional college courses for CNC programming. Believe me, I understand the need for practical knowledge just as much as the next guy.

I guarantee you have more machining experience then I, but do not try to deem my statements incorrect based on assumption. All my data is accurate, as I have nothing to gain from lying. Once again, I'm not trying to put you down, but simply standing behind what I said earlier.


Oh and also never stop learning! :bigok:

Couldn't agree with you more.

[TurDz]

damn....so what about the Greddy Ti exhuast? j/k...haha

Titan, you seem very qualified and look like you're on the right track to becoming a great engineer. The strength with engineers is their skill to apply actual theories and equations to real life. I have a professor t this quarter who is very qualified, phd from Stanford in ME, and he has been to numerous businesses and has increased their profits with simple applications of mechanical design princples (stess, fatigue, etc.)

I, on the other hand, have no ME experience at all, only a mandatory shop class with exposure to lathes, mills, drill presses, and an experience to watch a cnc lathe in action. I don't feel qualified at all at the moment. any recommendations on where to get pretty easy experience with my field? and I have a thermofluids midterm tomorrow morning...gotta get back to studying ;)

btw, im thinking, Titan and internetaardvark would be the perfect combo in developing great parts. I feel that the machinist has the experience (which takes YEARS to develop), while the mech. eng has the theories to reinforce and possibly find alternate solutions that save money while still meeting the criteria for a particular part.

[Titan]

I, on the other hand, have no ME experience at all, only a mandatory shop class with exposure to lathes, mills, drill presses, and an experience to watch a cnc lathe in action. I don't feel qualified at all at the moment. any recommendations on where to get pretty easy experience with my field? and I have a thermofluids midterm tomorrow morning...gotta get back to studying ;)


Shop class is extremely useful; probably one of the most useful experiences during your career. I wish shop class would be mandatory for all ME's, since it would give many of them the practical experience that is so desperately needed.

I remember a 3rd year ME student asking me what a weld was during a work term. Followed by another senior student being completely oblivious to the concept of threads. I see this day after day. It's not their fault for not understanding, it's the university's fault for not teaching them the most necessary of subjects. There is no doubt in my mind that hands on experience leads to an immensely greater mechanical aptitude.

In any case, to answer your question, I find night classes at local colleges to be one of the best sources for learning a fresh topic. I took a series of TIG welding courses while on a work term and they were invaluable. However, many times charges will apply. In that case, what I usually do is ask experienced people to show me a few things. I would spend extra hours off the clock at my work so I could watch and learn a few things from the cnc machinists. Whether they were actually teaching me at the moment or not, I still learned a great deal by just watching and asking questions. More often then not, they are more then happy to see someone interested in what they do. And the best part of all, it's free. Books can be decent for reference here and there, but I wouldn't recommend them for learning something new. Learning from friends is hit and miss, sometimes there is just too much "experience" based on hearsay.

[internetaardvark]

damn....so what about the Greddy Ti exhuast? j/k...haha
. . . . . . .btw, im thinking, Titan and internetaardvark would be the perfect combo in developing great parts. I feel that the machinist has the experience (which takes YEARS to develop), while the mech. eng has the theories to reinforce and possibly find alternate solutions that save money while still meeting the criteria for a particular part.
That is actually the way that manufacturing is ideally suposed to work. Specifically for that reason. The reality unfortunately isn't allways the same and one of the most common personall conflicts in a mfg shop is the machinist vs. mech engingeer. Mechanical engineers are taught to find the most cost effective way to get something done, in other words minumum amount of material required to hold a load etc. While machinists on the other hand have to cut the thing in the end so they tend a bit more towards overkill, ie they don't want to have to make something more than once and its a matter of pride that there parts work, as well as look, exceptionally well. If a machinist finds out that a part he made fails, assuming that he cares about/enjoys what hes doing, nine times out of ten he's going to feel semi responsible on some level, even when the failure has nothing to do with him. Or her, sorry. It's a matter of pride, the same as you would find with any kind of artisan. In adition to that there will always be machinists who think they are engineers, as well as engineers who think they are machinists. The reallity however is that if fore mentioned engineer was quallified to be a machinist chances are he/she would have been hired as a machinist, not an engineer, and vice versa. If you have one person trying to do the work of two people even if they have the knowledge and skill to pull it off, the outcome will suffer, because they are only one person doing the jobs of two people.

[internetaardvark]

That's where you are wrong. Adding aluminum DOES increase strength. Believe it or not, alloying materials can result in a material of HIGHER strength then either of the pure metals. It all has to do with the grain structure of the alloy relating to the distortion of crystal planes that, in turn, resist dislocations.

Take this for example:

Pure Copper Yield = 70 MPa
Pure Aluminum Yield = 35 MPa
Pure Nickel Yield = 110 MPA

Now look at the alloys of these materials:

Copper - 5% Aluminum Yield = 125 MPa
Copper - 70% Nickel Yield = 270 MPa

I felt the need to correct you because, as I mentioned in my first post, pure titanium is still weaker then steel. All my information is accurate, you can confirm it any material text. Do not take this the wrong way; this is not a personal attack. I am merely defending my original point.

Pure titanium would be inferior to steel from a strength point of view, yes. Keyword here is "pure". As I mentioned above and in previous posts, alloying titanium can increase its strength dramatically.

I am on coop. I work in the industry every alternate 4 months, for a duration of 4 months. Not much experience, true, but I am not entirely naive.

On every work term of mine, I have always taken the machinists' opinion over any engineers'. There is no denying it, for the majority of the time, practical experience will always conquer theory. Having realized this many years ago, I am not an egghead. I work on mills and lathes frequently. I am a TIG welder by hobby and am also in the process of taking additional college courses for CNC programming. Believe me, I understand the need for practical knowledge just as much as the next guy.

I guarantee you have more machining experience then I, but do not try to deem my statements incorrect based on assumption. All my data is accurate, as I have nothing to gain from lying. Once again, I'm not trying to put you down, but simply standing behind what I said earlier.

Couldn't agree with you more.

Titan you sound like a really cool guy, I'd love to be able to actually sit down and talk to you some time instead of just posting back and forth, but we got to use what we have. Now that said I'm still not sure that I know were your coming from, everytime I think I understand what your trying to say you make another post and just confuse the hell out of me. I'm not "trying to deem your statements incorect" based on anything let alone assumption. I've told you if and when I've disagreed with you, and why I do. And I'm really not trying to be a d### but you keep coming up with these numbers that we can suposedly find anywhere, why don't you cite where You got those numbers from.
[/QUOTE]I felt the need to correct you because, as I mentioned in my first post, pure titanium is still weaker then steel. All my information is accurate, you can confirm it any material text. Do not take this the wrong way; this is not a personal attack. I am merely defending my original point.[QUOTE]
Titan there is nothing to defend I'm not trying to prove you wrong, I don't want you to "defend" your statements I want you to "CLARIFY" your statements.
You say that Titanium is inferior to steel from a strength stand point due to its lower uts, despite the fact that it has a higher yeild strength, yet earlier you made a coment that a part is considered to have failed as soon as its yeild is reached. I pointed out the fact that if that is the case then titanium is in fact efectively stronger than steel and your defense was to post a graph that turned out to not even be a reflection of the materials in question.

You can't not see how that might cause confusion to someone, thats the point I was trying to make in the last post I made. I wasn't attacking you, I was asking you to clarify your statements. Thats all I've been trying to do, and yet you continue to defend your previous statements with facts that you claim to be true yet you list no sources for your information. Then you get defensive because you feel that I'm claiming that your supplying false info. I don't get you man, but I'm making an effort here to change that. But I can only do so much on my own. This is the last thread of this kind that I'm going to post here. If I have anything further to say in this vein I'll do it thru pm, and I hope you'll do the same. This has gone way past the point of being rediculous, I can only ask for clarification and be handed a defense so many times before it starts getting annoying. If you can clarify your statements then please do so, so that we can all actually "learn" something. Cause what your asking us all to do when you supply facts without backing them up, is "accept" something. I can't speak for anyone else here but I for one find it difficult to accept something on blind faith, that I don't aggree with. Some call that stuborn, others call it an inquisitive mindset, I call it a will to accept what is presented and not expected to be taken on blind faith. Its obvious that we dissagree on something here I'm willing to accept that, but don't expect me to just mindlessly accept information that makes no sense to me without questioning it. If everyone just accepted without questioning then this world would be a really boring place, look a Isak Newton, look at Einstein. Did you know that einstein actually almost flunked out of school when he was a kid? Most of the stuff he came up with was self taught. Well like I said I'm done here now. This thread needs to get back on topic. And I am in no small way responsible for that. But like I said if you make another post just keep in mind, I don't want defense from you, there is nothing to defend. I want clarification, if you can provide that please do, if not stop posting. And you don't have to say after every response that you aren't attacking me, I've never accused you of that as far as I can remember, and I don't feel that way now. However getting defensive is not going to help anyone to learn, espesially when there is nothing to defend against. Sorry if this comes off harsh but like I said I'm thru with this current vein of is starting to strongly resemble bickering.

[Titan]

For clarification purposes:


When I mentioned "strength" in my last post, I was referring to yield stress.

Commercially Pure Grade 1 Titanium (CP G1) Yield Stress: 25,000 psi (172 MPa)

Source: http://www.suppliersonline.com/propertypages/CPgrade1.asp



304 Stainless Steel Yield Stress: 29, 750 psi (205 MPa)




Point #1 - Based on these numbers, 304SS has a higher yield then CP-Titanium. Therefore, can be considered stronger in respect to a machine component.



Effects of Alloying Titanium:

Titanium Grade 2 (0.10% wt Carbon, 0.30% wt Iron, 0.03% wt Nickel)

Yield Stress: 40,000 psi (275 MPa)
Ultimate Tensile Stress: 50,000 psi (345 MPa)


Titanium-6Al-4V (0.08% wt Carbon; 0.25% wt Iron; 0.05% wt Nitrogen, 0.20% wt 0xygen, 5.50-6.75% wt Aluminum, 3.5-4.5% wt Vanadium)

Yield Stress: 120,000 psi (827 Mpa)
Ultimate Tensile Stress: 130,000 psi (896 Mpa)


Point #2 - The above shows that alloying elements can add a tremendous amount of strength to titanium.


Point #3 - Alloying elements of lower strength then pure titanium, such as Aluminum and Vanadium, can create a material with a higher strength then any of the pure elements alone.

Source: http://www.rembar.com/Titanium.htm


I hope this clarifies what I have stated in previous posts.