Simple test to distinguish mild steel rod from silver steel rod.

[Andrew TinsleyParticipant @andrewtinsley63637]

My stock of silver steel and bright mild steel rod have become mixed. I have sorted out the lengths of silver steel (usually 330 mm long or so) Some of the other material has been sawn down and I really can't tell the difference by eye.

I suppose I can mike up the diameters, which should sort out the high tolerance silver steel. I am just curious if there is another method?

Regards,

Andrew.

[Andrew TinsleyParticipant @andrewtinsley63637]

[EmgeeParticipant @emgee]

Turning some and/or a spark test may reveal the silver steel.

Emgee

[Bo’sunParticipant @bosun58570]

Hi Andrew,

I think you might be able to tell by the colour of the sparks from a grinder, but can't remember which is which.

Alternatively, look at the surface finish, with a magnifying glass if necessary. The silver steel should show grinding marks from centreless grinding.

[Andrew TinsleyParticipant @andrewtinsley63637]

Thanks Emgee, I suppose turning the samples would be a good way. Not too sure about a spark test, I didn't think there was much difference between the two. Just my memory and I stand to be corrected!

Andrew.

[EmgeeParticipant @emgee]

Andrew

You could cut a short length off and harden in the usual way, file test should provide an answer.

Emgee

[Mick B1Participant @mickb1]

Posted by Bo'sun on 16/04/2021 11:05:19:

Hi Andrew,

I think you might be able to tell by the colour of the sparks from a grinder, but can't remember which is which.

Alternatively, look at the surface finish, with a magnifying glass if necessary. The silver steel should show grinding marks from centreless grinding.

That's what I do. The difference between a drawn and ground finish is generally pretty obvious. I've come across PGMS, which would be a lot more difficult to distinguish, but I've only ever seen that in industrial situations – where it was worth paying for – never hobby.

[Roderick JenkinsParticipant @roderickjenkins93242]

The spark test does work – best tested by comparing with 2 known specimens. Measurement is pretty good as well since most mild steel bars are a couple of thou under the nominal diameter whereas silver steel is usually less than half a thou under.

HTH,

Rod

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello Mick,

A good magnifying glass should have been the obvious answer! It just never crossed my mind. Hardening and then filing is proof positive, but I wanted a less involved answer (being lazy!).Mind you if I was going to use it for a complex turning job, then I would go the hardening route. Too lazy to do the job twice if I got the wrong material!

Thanks everyone for putting me straight,

Andrew.

[SillyOldDufferModerator @sillyoldduffer]

Spark test, plenty of advice on the web, like this example:

Takes a bit of practice. Grind and watch known examples of various steels to see the difference before tackling an unknown metal. Silver steel sparkles more than mild-steel, but the difference is easier to see by comparison.

Dave

[Ady1Participant @ady1]

Silver steel makes a different much higher noise than ordinary metal, a different "ting"

[Mike PooleParticipant @mikepoole82104]

The ground finish is an easy check, if it’s not ground it’s not silver steel, the ground finish does not definitively make it silver steel as some stainless and PGMS can easily be mistaken for SS, if it hardens and measures very close to size then it is a very good chance it is SS, that will leave the problem of what the rest is. When stubs were a major SS producer they stamped their name on rods that were big enough but there are plenty of manufacturers who don’t. It’s worth having a paint or notch or dot code to Mark stuff up when it comes into the shop but if you are like me you will have a pile of unknown stuff that looked handy which can sometimes be a win and sometimes not worth the trouble.

Mike

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