stainless steel bolts

[Larry Wolff]

How can I tell if these bolts are stainless steel or not?
Loading Image...

All I know is they're heavy feeling - and magnetic.

But how do I know if they're stainless short of purposefully rusting them
by dipping them in acid?

[AMuzi]

Post by Larry Wolff
How can I tell if these bolts are stainless steel or not?
https://i.postimg.cc/8cMgwY4Y/bolts.jpg
All I know is they're heavy feeling - and magnetic.
But how do I know if they're stainless short of purposefully rusting them
by dipping them in acid?

There are a lot of stainless steels. Some are more magnetic
than others, corrosion resistance varies widely. Short
answer = no general answer:

https://www.unifiedalloys.com/blog/stainless-grades-families

Some direction for your analysis:
https://www.engineeringtoolbox.com/identification-stainless-steel-d_383.html

[Ed P]

Post by Larry Wolff
How can I tell if these bolts are stainless steel or not?
https://i.postimg.cc/8cMgwY4Y/bolts.jpg
All I know is they're heavy feeling - and magnetic.
But how do I know if they're stainless short of purposefully rusting them
by dipping them in acid?

Can't tell from looking, but they look very shiny, like a plating. I'd
see what a magnet does, though some alloys are somewhat magnetic.

[Frank]

Post by Larry Wolff
How can I tell if these bolts are stainless steel or not?
https://i.postimg.cc/8cMgwY4Y/bolts.jpg
All I know is they're heavy feeling - and magnetic.
But how do I know if they're stainless short of purposefully rusting them
by dipping them in acid?

As others point out some grades of stainless are magnetic.

Looking it up I see there are tests you can run:

https://www.waterbottle.tech/simple-methods-for-identifying-stainless-steel/

Been a long time but I remember running tests on various grades to see
if they would stand up to making polymers under highly acidic
conditions. You might do something similar to see if they will hold up
under the use you are putting them to.

[Paul in Houston TX]

Post by Larry Wolff
How can I tell if these bolts are stainless steel or not?
https://i.postimg.cc/8cMgwY4Y/bolts.jpg
All I know is they're heavy feeling - and magnetic.
But how do I know if they're stainless short of purposefully rusting them
by dipping them in acid?

If the pic is of the actual bolts...
The bolts do not look like stainless - they look like low quality steel
bolts plated with zinc. The manufacturing looks poor.
IMO, they are the 13 cent variety, not the $1.13 variety. Same for the
nuts. They are the 5 cent variety, not the 55 cent variety.
There is low quality stainless but I have never seen that used in nuts
and bolts. Threaded pieces are normally 18-8 or better and have better
machining.

[Colour Sergeant Bourne]

Post by Paul in Houston TX

Post by Larry Wolff
How can I tell if these bolts are stainless steel or not?
https://i.postimg.cc/8cMgwY4Y/bolts.jpg
All I know is they're heavy feeling - and magnetic.
But how do I know if they're stainless short of purposefully rusting them
by dipping them in acid?

If the pic is of the actual bolts...
The bolts do not look like stainless - they look like low quality steel
bolts plated with zinc.  The manufacturing looks poor.
IMO, they are the 13 cent variety, not the $1.13 variety.  Same for the
nuts. They are the 5 cent variety, not the 55 cent variety.
There is low quality stainless but I have never seen that used in nuts
and bolts.  Threaded pieces are normally 18-8 or better and have better
machining.

Whar are the tip-offs in the picture that they ared ow quality?

[Paul in Houston TX]

Post by Colour Sergeant Bourne

Post by Paul in Houston TX

Post by Larry Wolff
How can I tell if these bolts are stainless steel or not?
https://i.postimg.cc/8cMgwY4Y/bolts.jpg
All I know is they're heavy feeling - and magnetic.
But how do I know if they're stainless short of purposefully rusting them
by dipping them in acid?

If the pic is of the actual bolts...
The bolts do not look like stainless - they look like low quality
steel bolts plated with zinc.  The manufacturing looks poor.
IMO, they are the 13 cent variety, not the $1.13 variety.  Same for
the nuts. They are the 5 cent variety, not the 55 cent variety.
There is low quality stainless but I have never seen that used in nuts
and bolts.  Threaded pieces are normally 18-8 or better and have
better machining.

Whar are the tip-offs in the picture that they ared ow quality?

It's difficult to say for sure with out viewing the head markings or
seeing better photos. It could be the small pixel count of the photo or
the zinc plating, but... the machining just does not look crisp / sharp.
There are striations on the bolt head and nut that are not seen on
quality bolts and nuts. The nut appears to be much thinner than a good
quality nut.

[Scott Dorsey]

Post by Paul in Houston TX
It's difficult to say for sure with out viewing the head markings or
seeing better photos. It could be the small pixel count of the photo or
the zinc plating, but... the machining just does not look crisp / sharp.
There are striations on the bolt head and nut that are not seen on
quality bolts and nuts. The nut appears to be much thinner than a good
quality nut.

There are good fasteners, crappy fasteners, and the very worst,
electrician-grade fasteners.

Striations are a bad sign and so are threads that aren't cut sharply, or
even worse appear to be rolled rather than cut.
--scott

[Mark Olson]

Post by Scott Dorsey

Post by Paul in Houston TX
It's difficult to say for sure with out viewing the head markings or
seeing better photos. It could be the small pixel count of the photo or
the zinc plating, but... the machining just does not look crisp / sharp.
There are striations on the bolt head and nut that are not seen on
quality bolts and nuts. The nut appears to be much thinner than a good
quality nut.

There are good fasteners, crappy fasteners, and the very worst,
electrician-grade fasteners.
Striations are a bad sign and so are threads that aren't cut sharply, or
even worse appear to be rolled rather than cut.

Rolled threads can have some advantages over cut threads. It depends
on the material and the application. They are not always inferior.

https://accu-components.com/us/p/360-rolled-thread-vs-cut-thread-the-differences-benefits-of-each-thread-type

I agree that the fasteners in the photo look like poor quality parts.

[Larry Wolff]

ALL Quality bolts have roll-formed threads. Cut or in this case
"torn" or "chewed" threads are almost exclusively the domain of cheap
crappy fasteners.
These are definitely NOT rolled threads and appear to have been cut
with a worn out harbor fright dieset - - -

Thanks for looking at the threads. Here's a clearer picture of them.
Loading Image...

These are for outdoor lights bolted high up where, if they rust, then it
will be very hard to get them unbolted while perched tall on a ladder.

[Jim]

Post by Larry Wolff

ALL Quality bolts have roll-formed threads. Cut or in this case
"torn" or "chewed" threads are almost exclusively the domain of cheap
crappy fasteners.
These are definitely NOT rolled threads and appear to have been cut
with a worn out harbor fright dieset - - -

Thanks for looking at the threads. Here's a clearer picture of them.
https://i.postimg.cc/Vst7x1NL/boltsqj48.jpg
These are for outdoor lights bolted high up where, if they rust, then it
will be very hard to get them unbolted while perched tall on a ladder.

"https://www.mcmaster.com/products/screws/hex-head-screws~/material~stainless-steel-2/"

[AMuzi]

Post by Paul in Houston TX

Post by Colour Sergeant Bourne

Post by Paul in Houston TX

Post by Larry Wolff
How can I tell if these bolts are stainless steel or not?
https://i.postimg.cc/8cMgwY4Y/bolts.jpg
All I know is they're heavy feeling - and magnetic.
But how do I know if they're stainless short of
purposefully rusting them
by dipping them in acid?

If the pic is of the actual bolts...
The bolts do not look like stainless - they look like low
quality steel bolts plated with zinc.  The manufacturing
looks poor.
IMO, they are the 13 cent variety, not the $1.13
variety.  Same for the nuts. They are the 5 cent variety,
not the 55 cent variety.
There is low quality stainless but I have never seen that
used in nuts and bolts.  Threaded pieces are normally
18-8 or better and have better machining.

Whar are the tip-offs in the picture that they ared ow
quality?

It's difficult to say for sure with out viewing the head
markings or seeing better photos.  It could be the small
pixel count of the photo or the zinc plating, but... the
machining just does not look crisp / sharp.    There are
striations on the bolt head and nut that are not seen on
quality bolts and nuts.  The nut appears to be much thinner
than a good quality nut.

You're right, it's difficult to say with certainty.
There are chemical and spark tests which I linked in a reply
the other day which are much better than images.

Here are M5 ULS stainless we sell in a parts packet:
Loading Image...

Typical SNP steel ULS:
https://helmi-sport.de/en/p/uls-screws-m6x20

Loading Image...

depending on the camera and lighting they look pretty much
similar.

[Larry Wolff]

Post by AMuzi
depending on the camera and lighting they look pretty much
similar.

Thanks for all the kind help from all you wonderful folks.
You were all right. The seller lied to me about the bolts.

I left the bolts outside in the rain and they rusted already.
Loading Image...

So I guess they're exactly what most of you said they were.
Cheap bolts!

Suitable for a car perhaps. Or maybe only indoors.
I don't know but they rusted already outdoors in the rain.

They're no good for outdoor use for an outdoor pole light
as by the time I need to take it down, they'll be rusted up.

Ever been there before?

[Paul in Houston TX]

Post by Larry Wolff

Post by AMuzi
depending on the camera and lighting they look pretty much
similar.

Thanks for all the kind help from all you wonderful folks.
You were all right. The seller lied to me about the bolts.
I left the bolts outside in the rain and they rusted already.
https://i.postimg.cc/hvVYqqcX/rusted-qj4-8-bolts.jpg
So I guess they're exactly what most of you said they were.
Cheap bolts!
Suitable for a car perhaps. Or maybe only indoors.
I don't know but they rusted already outdoors in the rain.
They're no good for outdoor use for an outdoor pole light
as by the time I need to take it down, they'll be rusted up.
Ever been there before?

Oh yes!!! I bet that we all have been there before.
Thank you for following up with the photo.
I started using SS fasteners years ago for many things, but not all.
Each metal and alloy has different properties and uses.

[Xeno]

Post by Colour Sergeant Bourne

Post by Paul in Houston TX

Post by Larry Wolff
How can I tell if these bolts are stainless steel or not?
https://i.postimg.cc/8cMgwY4Y/bolts.jpg
All I know is they're heavy feeling - and magnetic.
But how do I know if they're stainless short of purposefully rusting them
by dipping them in acid?

If the pic is of the actual bolts...
The bolts do not look like stainless - they look like low quality
steel bolts plated with zinc.  The manufacturing looks poor.
IMO, they are the 13 cent variety, not the $1.13 variety.  Same for
the nuts. They are the 5 cent variety, not the 55 cent variety.
There is low quality stainless but I have never seen that used in nuts
and bolts.  Threaded pieces are normally 18-8 or better and have
better machining.

Whar are the tip-offs in the picture that they ared ow quality?

Having had experience with high quality bolts would be a start. Then
look at the thread - that is visibly of poor quality, as is the shaping
of the head of the bolt. Overall, looks like cheap Chinese shit!

[Larry Wolff]

cheap-assed chinese electro-zinc plated grade 2 would be my guess.
What markings *(if any) on the head?

I never thought of looking at the head of the bolt, which does have soem
"secret code" written on it as you can see in the photo of the head here.
Loading Image...

What do those strange markings mean to you? "Q J 4.8."

[Ed P]

Post by Larry Wolff

cheap-assed chinese electro-zinc plated grade 2 would be my guess.
What markings *(if any) on the head?

I never thought of looking at the head of the bolt, which does have soem
"secret code" written on it as you can see in the photo of the head here.
https://i.postimg.cc/t4NwLb2V/qj4-8-bolts.jpg
What do those strange markings mean to you? "Q J 4.8."

Grade 4.8 is a standard for fasteners like bolts, screws, and studs,
which are made from low or medium carbon alloy steel. The numbers on
fasteners, such as 4.8, 8.8, 10.9, or 12.9, indicate the tensile
strength in the first digit and the yield strength in the second digit.

Here are some characteristics of Grade 4.8 fasteners:
Tensile strength: For low carbon steel, the tensile strength is around
420 Mpa, and for medium carbon steel, it's around 500 Mpa.

Core hardness: The core hardness is between B71–95 on the Rockwell scale.

Size range: The size range for a fully or partially annealed Grade 4.8
screw is between M5 to M100.

Uses: Grade 4.8 fasteners are used in mechanical equipment, buildings,
bridges, tunnels, and high speed railways.

Strength: Grade 4.8 bolts are commonly referred to as high strength bolts.

[AMuzi]

Post by Larry Wolff

cheap-assed chinese electro-zinc plated grade 2 would be my guess.
What markings *(if any) on the head?

I never thought of looking at the head of the bolt, which does have soem
"secret code" written on it as you can see in the photo of the head here.
https://i.postimg.cc/t4NwLb2V/qj4-8-bolts.jpg
What do those strange markings mean to you? "Q J 4.8."

Metric low grade carbon steel bolt:

https://www.engineeringtoolbox.com/steel-bolts-metric-grades-d_1428.html

[Harry S Robins]

Post by Larry Wolff
I never thought of looking at the head of the bolt, which does have soem
"secret code" written on it as you can see in the photo of the head here.
https://i.postimg.cc/t4NwLb2V/qj4-8-bolts.jpg
What do those strange markings mean to you? "Q J 4.8."

400Mpa nominal tensile slrength with 80% yeild - msfium carbon
steel. no idea what the QJ stans for

In some other contexts, I've seen it stand for Quanjiangcun, a manufacturing
district in China. Not sure if that applies here. Probably not.

QJ shows up in places but it's never explained what it means when it does.

BOLT 5131014179 QJ 4.8
https://www.mowermagic.co.uk/acatalog/BOLT---5131014179---QJ-4.8-5131014179.html

Stainless Steel Hex Head Bolts QJ 2394
https://www.ss-bolt.com/sale-30872879-stainless-steel-hex-head-bolts-qj-2394-1992-stainless-steel-304-m2-m12-hexagon-head-nuts.html

The word is associated in other links to "Quick Joint" though.
But I can't pin it to these bolts on my own but only to joints.

1 1/2" Guardian Quick Joint QJ Stainless Steel Compression Fitting
https://www.ebay.com/itm/335193829655

Quick coupling fittings for tank - Quick Joints QJ
https://www.bucchi.it/en/prodotti/m04-soluzioni-tecniche-innovative/c08-raccordi-rapidi-ad-innesto-per-serbatoio-quick-joints-qj

[AMuzi]

Post by Harry S Robins

Post by Larry Wolff
I never thought of looking at the head of the bolt,
which does have soem
"secret code" written on it as you can see in the photo
of the head here.
https://i.postimg.cc/t4NwLb2V/qj4-8-bolts.jpg
What do those strange markings mean to you? "Q J 4.8."

 400Mpa nominal tensile slrength with 80% yeild - msfium
carbon
steel. no idea what the QJ stans for

In some other contexts, I've seen it stand for
Quanjiangcun, a manufacturing
district in China. Not sure if that applies here. Probably
not.

QJ shows up in places but it's never explained what it means
when it does.
BOLT 5131014179 QJ 4.8
https://www.mowermagic.co.uk/acatalog/BOLT---5131014179---
QJ-4.8-5131014179.html
Stainless Steel Hex Head Bolts QJ 2394
https://www.ss-bolt.com/sale-30872879-stainless-steel-hex-
head-bolts-qj-2394-1992-stainless-steel-304-m2-m12-hexagon-
head-nuts.html
The word is associated in other links to "Quick Joint" though.
But I can't pin it to these bolts on my own but only to joints.
1 1/2" Guardian Quick Joint QJ Stainless Steel Compression
Fitting
https://www.ebay.com/itm/335193829655
Quick coupling fittings for tank - Quick Joints QJ
https://www.bucchi.it/en/prodotti/m04-soluzioni-tecniche-
innovative/c08-raccordi-rapidi-ad-innesto-per-serbatoio-
quick-joints-qj

Metric Grade 4.8 is the key information.