SReynolds

Steel Grade for "Grade 8 Bolt" ???

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far better to be expected to sit around the garden looking cute than to be double digging the caliche with a spoon!

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I work at a refinery.  We have a lot of bolts around that hold flanges together keeping stuff like gasoline, crude oil and a bunch of other stuff from leaking.  Grade 8 bolts are stronger than 5.   We don't specify bolting based on carbon content for blacksmithing tools... ;o).    Bolting is usually more about strength and temperature and also corrosion.   Higher temps usually mean stronger bolts or bolting that is less effected by temperature.   Hot weak bolts that lose tension under application of temperature and pressure will leak at bolted pipe connections.  That is bad.   There is another thread here that talks about 718 material.   We have a piping system that operates at 1000F and 3000 PSI.  It has 718 bolts that have excellent hight temperature strength.   grade 5s would be bad.  grade 8s would be bad but not as bad as 5s.  718 is great!  As for chemistry you can find that online all over the place as already mentioned.   The other piece is that alloy bolts like stainless will elongate more with temperature than some other materials.   Bolts that elongate too much when heated can be a problem.   It is all about keeping the gasket in a flange compressed and holding pressure of the stuff in the pipe.   And yes zinc or cadmium coating can be a problem at high temps due to liquid metal embrittlement.     This is also a consideration in case there is a fire.

Edited by Borntoolate

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The way I see it explained in a lot of old books is that a point is "one percent of one percent."  Everyone's probably already got that by now, but I threw in my 2 points just in case.

​That would be 0.0002  ;)

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Well, that’s why we have google. I am sure some manufacturer of grade 80 or grade 100 chain is proud of the steel they use. That’s how I came up with the alloy for grade 5 and grade 8 bolts. It took a bit on the latter to find out that they typicaly use the same alloy but heat treat it differently. 

A note from an old mechanic, in thick flanges (same for engine heads) bolt stretch becomes an issue. Bolt stretch can be your friend (acts as a lock washer) or your enemy (you over tight end the bold and it has now permanently elongated). Metallurgy and engineering are part of bolt desighn. 

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The coating on alloy chain is no good, and the steel alloy is different from manufacturer to manufacturer.i will use high carbon chain and powdered metal for the project.See i did my research,and know how to google. Too many xxxxxxxx xxxxxxx here .:(

 

 

Edited by Mod34
Edited for inappropriate language

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Don't worry, I'll leave you alone if you're going to call names.

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On 4/20/2015 at 1:37 PM, Charles R. Stevens said:

grade 8 can provide higher clamping loads but is not recomended for loads in shear

Drat, I wish I had seen this sooner.  I just paid extra for a handful of Grade 8 bolts to tie down my fly press (walks far too much in use).  Probably will be fine as regards shear since I'm going to use expansion inserts in the floor and some of the force will be taken up by deformation of the lead, but still...

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You have a fly press now? I'm definitely coming by the next time I'm in town!

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Gub, your not the only person who is reading (or will be reading this thread) I meant no slight as to your intelligence or ability (if I thought you to be an idiot I would have in all likelihood ignored you). But as we have this wonderful thing called the internet and a few generations of seemingly ignorant and lazy folks coming threw here I figured an explanation as to how I came to that answer was appropriate. As I don’t feel sufficiently curious about grade 80 or 100 chain to look it up and share it with you. 

Sorry to bust your bubble. But hey if you want to call me Richard Cranium or some such feel free, get it off your chest. 

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Charles: Isn't there a likable young man on IFI who calls himself Gub? We don't want to confuse the two do we?

Frosty The Lucky.

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Nope, we don’t. I’m willing to give Mister Tinnerman a chance tho, we all have bad days (some of us more than others) let’s see how his attitude changes after time to reflect, moderation does the soul good...

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We're on the same page, everybody deserves a few chances I just don't want  more confusion than necessary. I do the same thing regarding blacksmith terms it makes talking easier if everybody knows what we're talking about.

Frosty The Lucky.

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On 4/22/2015 at 11:45 AM, Charles R. Stevens said:

I am glad I stuck my foot in my mouth...

I'm reedicated and a new guy gets off on the right foot

Charles, some of us just might be better smiths (and farriers) than mathematicians...LOL!! 

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Dainty!   (mine are 13 EEEE); currently wearing German combat boots to work, size 47.

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