Identifying Steel types.

Hello Forum,

I purchased a length of 'free cutting mild steel' a while ago. I turned various parts using it and was very impressed by the quality of the surface finish. Every other length of 'free cutting mild steel' I have used since has been poor in comparison. I took a sample back to the supplier and they had no knowledge of what it was they sold me. They claimed that all their stock was the same material, but my results showed that this was not the case.

I did some googling on various forums to try and understand what kind of finish to expect from different grades of steel and decided that what I must have was EN1A. I ordered a length and tried some test cuts with the same insert/feed rate/cutting speed/cutting fluid and the results were no where near as good so decided it was not EN1A.

Short of sending a sample to a professional laboratory to perform a proper analysis, I'm stuck for ideas to enable me identify it and get some more of the same. It really is so much better than any mild steel that I have used since and it stands in my stock rack reserved like a fine wine for extremely important jobs. Every time I cut a piece off, I realise that one day it will all be gone. I really like this stuff and I want to buy some more.

Does anyone have any recommendations? It looks like stainless and has no surface rust at all, although it is not as hard. It turns beautifully, from reasonably large cuts, to very light cuts.

Thanks for any help anyone can offer.

Neil.

It may be 416 stainless, or 303 stainless.

416 is a cheap martensitic variety with lower resistance to corrosion than the 300 series. It machines beautifully. Many linear motion components are made of it (ballscrews and LM guides).

303 is similar, but has lower machinability and does not respond to heat treatment.


You may find 416 in printers. The ground and polished rods that form the base of their LM are typically made from it.

I wish you well in the search for the steels identity.
Having analysed steels in my previous jobs, I can tell you that the analysis does not tell the whole story.
Most steel types have a wide variation of alloying contents and can all be in grade. This is due to the steel being within its physical specifications and the chemical content can vary widely.
From your description it sounds like you got some high quality free machining steel, which I think contains Lead.

Peter

Hi Peter,

Thank you for the response. Can you recommend which steel to ask for and a supplier. I am happy to buy some and see how it compares.

Neil.

Hi Peter,

Thank you for the response. Can you recommend which steel to ask for and a supplier. I am happy to buy some and see how it compares.

Neil.

This is probably a silly suggestion, but is the end of the bar painted blue?

From memory (I shall check tonight), one end was painted orange.

Here is a colour chart http://www.alro.com/datapdf/metals/colorcodechart.pdf.
Although it may mean nothing as suppliers usually had their own version.
As to the steel type you need I have no real idea as I only used to analyse them to see if they were in spec, more often than not they had selected the wrong one! Happened more than once!


Peter

Quote:

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Originally Posted by ptjw7uk

Here is a colour chart http://www.alro.com/datapdf/metals/colorcodechart.pdf.
Although it may mean nothing as suppliers usually had their own version.
As to the steel type you need I have no real idea as I only used to analyse them to see if they were in spec, more often than not they had selected the wrong one! Happened more than once!

Peter

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If your old company can't select the right one, its not looking good for me :dispirited:

Thanks, Neil.

Try asking here
Forum Topics - Model Engineer
Mike