Hey, welcome back to Albany County Fasteners - Fasteners 101
I'm Bob and today we're going to talk about different grades and types of bolts.
Let's get started.
So I have an array here of different types of materials.
I want to go through the materials first
and give them the magnetic test.
So I have a magnet here to show you.
So first I have a 316 stainless, which is this one here,
I have a 18-8 stainless, a brass hex cap screw and a silicon
bronze hex cap screw, this is hot-dip galvanized,
this is plain grade eight or better ,
zinc plated hex cap screw,
another zinc hex cap screw but in a different grade,
so this is just a standard grade but I'll go through the grades in a second
and I have a great 8 yellow zinc coated.
So I just wanted to give these a magnet test so you can see some are magnetized
others are not. This is a 316 stainless
and in this situation there's no pull from the magnet.
This is an 18-8 which has very little pull, as you can see.
Not much but there is some partial magnetic field to that.
This is brass.
Brass has no magnetic field to it at all.
Silicon bronze, this is silicon bronze.
This is also, just so you know, used in heavy salt water applications such as on boats.
This is a heavily used item for fasteners with saltwater day in and day out.
No magnetic pull on that.
This is a hot dip galvanized hex cap screw.
So this is alloyed steel and just coated with hot-dip galvanized (zinc).
You can get some decent corrosion resistance out of that
and, you can see, the magnet sticks right to it.
Grade 8. This is just a grade 8 plain bolt.
Magnetized. Zinc coated or plated.
Another zinc plated and then grade 8.
You can see all these have heavy magnetism.
So I just want to go through the different grades that we have.
This is a grade 8 hex cap screw.
You can tell by the markings on the head, but I'm going to show you an even better one.
This is a large grade 8 bolt and there you can see the markings.
These markings on this head indicate-these slashes
these 1-2-3-4-5-6 slashes that you see here,
those slashes indicate that that's a grade 8 bolt.
These letters that you're seeing is the manufacturer's markings so they can identify,
should the bolt fail,
they can identify if this is their bolt or not.
So typically grade eight, in most cases, is coated in yellow zinc.
You can see this bolt, it's coated with a yellow zinc.
These are typically, grade eights are heated to temperatures of 800 degrees.
These are very commonly used in situations where you need a very strong bolt.
I have here a grade 5 bolt.
You can see these three slashes.
So three slashes on a grade 5 bolt.
You'll see again these letters; these again are the manufacturers letters.
You can see the grade 8. This is how you tell the difference.
What you're buying.
So when you go out and you're looking for a grade 5 bolt,
you're always looking for the three slashes on the bolt.
It's standard through the industry.
This is a grade two bolt.
This grade 2 bolt has no markings, no slashes at all.
The only thing that you're going to see on here is the manufacturer's initials or their letters.
This is a structural steel bolt or they call this a structural bolt.
You can get structural bolts, structural washers, and structural nuts in A325 (alloy),
they have a 520, I think a 524 or 536
in nuts, but this is a structural bolt used in structural steel applications.
These typically fall into the ASTM A193
which are typically heated somewhere around 1,600
degrees and treated in that fashion, but
I would refer you onto the ASTMs.
These are also, just so you know, are plain and oiled finished.
That's the only way they, oh I'm sorry, they do come in hot dip galvanized also,
but the most common used is oil finish.
As far as grades go,
I was showing you the grades, most plain bolts, other than structural, will have
the grade 8 markings on them.
Ours are grade eight or better, and that's the way that they're indicated on our website
as grade 8 or better, and you will see the grade 8 slashes on the head.
That will indicate, the six slashes will indicate,
that that's a grade 8 bolt and it has been
treated, heat treated, through-throughout
the bolt so it is hard enough not to
break for you.
This I spoke to you before: hot-dip galvanized bolts are typically
just grade 2 bolts and they are treated
and dipped into a hot dip galvanized bath
and they're brought out of the bath and then drained.
Silicon bronze is, like I said, mostly used on boats,
saltwater applications, they're using electrical panels for
many different reasons.
This is very common in those applications.
Brass again used in plumbing, hot water, these typically have no
heavy strength to them at all.
You would find these to be the standard type 2, or
equal to type 2 bolts.
18-8 stainless. These are typically heated up to about 400,
I'm sorry, 650 degrees when they're treated.
They can range anywhere from a grade two to a grade five depending upon the manufacturer.
This is a grade 316 stainless.
So silicon bronze is composed of copper, silicon, and other
alloys: tin, zinc, iron, magnesium,
which makes them corrosion-resistant for
marine and freshwater applications and
they're used in electrical panels as I
mentioned to you.
You'll find alloy steel, which are these here.
Alloy steel is made from high-strength steel, alloyed, heat-treated, so that would be
the grade eight. These are all alloys.
So grade 8, heat treated.
So these overtime, just so you know, have a zinc finish on them and they
do not have any long lasting rust resistance at all.
Hot dipped galvanized are from alloyed steel.
They're dipped in molten zinc.
These typically have to have thicker threads.
You cannot use a zinc nut with a hot dip galvanized nut,
it just won't go on properly and you're going to have problems.
So because of the hot dip galvanizing process,
(the zinc) is so thick they have to adjust the threads so they'd properly
coat the thread so there would be rust resistance of the hot galvanizing.
So I just wanted to bring up about the brass, it's solid brass
and with solid brass it's copper and zinc.
There is brass out there that they do use lead in.
Lead is used today in many, many brass products.
That's why in California there's a prop 65 that we have to warn that it could be cancerous.
We do bring that to everybody's attention in reference to brass.
Brass is not always what they say or call a solid product.
So I just wanted to bring that to your attention and educate you on the different grades
and the different coatings along with
different metals that are used and I
just want to brush over the different
heat treatments. So with a grade 8,
this falls under the SAE J429.
So you can look that up to go over on google.
Just google that and you'll find all the information in reference to the treatment of a grade 8 bolt.
A grade 5 bolt falls under ASTM 574.
A grade A325 falls under ASTM specifications also
and you can look those up on google to get further information.
That's our video for today.
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