Creep Comparison

I'm surprised that a mechanical engineer would not know about these things, oor how to find the answers.

I'd look on-line for the mechanical properties of the materials in question and look at the controlling specification to determine what is acceptable and what is not.

MatWeb or Engineering Toolbox are both good material properties resources on-line. (Usual Disclaimer)

what are u surprised of ? i have 4 years of experience in total ...... if i ask u to give me answer, can u use A193 B7 instead of A193 B16 on system having 500C operating temperature.....

Don't be over smart ! u also would know many things in life.... Grown up Mr........ give other the right to ask Question.... remember Eistein failed in first 200 attempts later He became Genius

CR4: The Engineers Place for News and Discussion^®.

You asked: "i want to have your opinion about the following topic." You received an opinion. Why the vitriolic response?

Who is "Eistein", and why did he fail 200 times? At what did he fail to do so often? What does that have to do with the issue at hand? Perhaps ask this Eistein "i want to have your opinion about the following topic." and see what he says.

Maybe he meant Edison?

Dare I ask for clarification?

Is this a good example of Ronseto's definition of an "Active Contributor?

_{Now I'm being snippy.}

I think you are correct in the Edison guess. Makes more sense than Einstein. That was a part of the friendly interactive banter I was hoping for. That hope has been dashed upon the rocky shores of the uncharted Island of Active Contributors.

Not sure just what to think about Ronseto's thread.

Faisal, after reviewing you previous interaction with the CR4 group, I wish to ask that you disregard my previous comment. It was intended to entice a response from you, the result of which may have resulted in some useful answers for this thread.

You obviously have neither time nor tolerance for such foolishness. Please forgive me.

Well I think that the OP as a working engineer should know where to obtain this info on his own, I mean what would he do if the internet didn't exist?? And to just use the internet to ask other people the question, seems to defeat the whole purpose of the internet in a situation like this, where the info could be found directly on-line...Now if you're in a hurry and don't have time to search on your own, that would be different...Even though I would think that most people have shortcuts to sites on their desktop that they use on a regular basis..But having said all that, assistance should be requested with suitably humble platitudes, and received with feined gratuitous praise...

Sorry you took such offense. Not sure why.

You seem rather sensitive to me. I expressed an opinion, that's all. That's still allowed, I think.

Good luck in your quest for knowledge.

The less expensive B7 fasteners are an acceptable substitution for B16 fasteners

Please note this comment is sarcastic and b7 fasteners are not an acceptable substitute for B16 at the temperature range of application. As noted by this post's author in a subsequent posting.Milo

Thanks to all,

Well Well what can i say, i just ask for people's opinion / Expert advice can we use A193 B7 instead of A193 B16 (remember designer have recommended A193 B16).

Please i am a knowledge seeker dont take me wrong. i dont have too much money to buy stuff oline. To all Guru's whether it is edison or einstein my point is that let people ask question if you think it is nt upto the mark please ignore it.

i am on project of 115000bpd oil refinery relocation project, initial date of construction is 1967. Due to high cost, one of my seniors ask me to find some kind of comparison b/w B7 ,B16. Project includes entire refurbishment of refinery, construction and later comissioning. I am living in very remote area and dont have full internet access for the very reason i came here after long time and though people like Ahmed ghalali can give me advice or proper answer with proper refrence.

I appologize if any is hurt due to my rash behavior, i know humbly request you all to please help me in this matter.

Well alrighty then...

ASTM A193 Grade B7
ASTM A194 2H Heavy Hex Nut
B16 Offers slightly higher temperature resistance than B7, with B7 at (Liquid quench -50° to 900°F, Air quench -40° to 900°F ) and B16 at (-50° to 1100°F.)

Your 510C max working temp is 950F which exceeds quench temp for B7....

It's not recommended...

No disrespect to Anonymous Poster #1, but I wouldn't make the change without a lot more investigation. On an oil refinery, with bolts at ~ 500°C, if there's a failure there could be a major problem. Can you imagine trying to justify yourself by saying "An Anonymous Poster on CR4 said it would be alright"?

In any case, I'd expect the creep to depend on bolt working stress, and you haven't given that.

Thanks, Codemaster.....you have taken the bait and exactly made my point

No offense taken....!!!!

As a senior engineer with nearly 40 years of experience, I certainly wouldn't trust any cheap advice gleaned from such a shoddy source as CR4....... You get what you pay for.

The most recent revelation by the OP tells us that we have yet another failure of management as there is an effort to "cheapen up" the fastener materials..... an extremely dangerous decision that has been obviously dumped on a hysterical and sensitive arab newbie.

I sense the presence of an MBA....

THIS IS THE TRUTH ! ! B7 is NOT AN ACCEPTABLE SUBSTITUTE FOR B16 !!

B16 EXISTS BECAUSE THERE ARE LIMITATIONS TO B7 FASTENERS ! !

I suggest the purchase and review of engineering texts on fasteners.

Here is some obvious fastener information that even the lazy could find:

www.pifstems.com/tech.html

Responses......anyone ???

No offence intended, but I don't see how my response amounts to "taking the bait", I was simply suggesting caution. If the OP had taken your #5 at face value and there was an incident, lives lost etc, would you have thought it was a good laugh?

Codemaster.....there was one day of time delay between my first and second post. There was no real risk. I provided an informative link that the OP could have found if the OP had performed even the simplest of searches.

If the OP decided to use the cheaper B7 fasteners based on "permission" granted from an unknown person from CR4, ....heaven help them all.

I was trying to point out the farcical nature of most of these questions and the imperious nature of the posters. They either want to be spoonfed/educated or have someone else do thier hard work for them. The forum and posters encourage such behavior.....Its really just sad

Its too bad that this forum has devolved to a mechanism for the inept and lazy to abuse the goodwill and helpful intentions of the experienced...

The CR4 management will delete this post anyway...

No they won't ! But good points well made.

When service temperature is more then 400°C, and OEM recommendation is also for B16 studs, please do not use B7 studs. Cost difference will be nominal but the risk involved is dangerous. There is a saying, cheap options may cost you more then correct options in long run.

Correct. I think the same goes for high speed centrifugal cases.

I was involved in a fire on a "UOP Platformer" at Coastal States refinery in 1974. The exchanger on the reactor discharge had a flange spread coming up to temp. It wasn't pretty. In addition to the right "studs" you better have a "Hot Bolt Crew" that is on the ball or you will have a Blow Torch that you will not belive!!!

yes it is also UOP platformer. whts yr advice may i use B7 inplace of B16 ?.. it seems not safe from the data share in other post....

We always had a UOP engineer on site. If you change UOP specs. not only do you need (UOP) approval you are endangering lives. I am not qualified to tell you the specs. for what application you are subjecting these studs. Solar Eagle has given you correct ASTM on them, however I highly recommend you get in touch with a UOP Rep. for your own peace of mind. I think the flange material/Temp. comes into play as well as hot bolt torque. Be Careful..

Thanks to all :) now kindly close this topic please....