463 forum posts
2036 forum posts
Then you are using it for the right purpose, it is not intended for structural work, this applies to both BMS and black steel. Here is a quote of a typical chemical analysis for 070M20 (EN3A), the bright version is EN3B.
It should conform at least roughly to that analysis, I don't see a mention of boron in there, I know it's hard to test this, but if it isn't conforming to these numbers, it isn't mild steel by definition. And i'd imagine it certainly wouldn't be what the common stockists will be offering. If you go to a scrap yard or recycling plant for steel, you can expect the lottery that comes with it.
Edited By Michael-w on 02/01/2017 18:41:38
463 forum posts
|not done it yet||02/01/2017 20:29:27|
|2042 forum posts|
I would suggest that the problem that vintage engineer refers to is one of cheapo recycling. Poor homogenisation of the constituents while in the melting pot? Certainly there would be variations between batches but that should, with quality control, be minimised.
The problems could be avoided, but at a price as usual.
|Dave Halford||02/01/2017 20:32:52|
|218 forum posts|
I have some old 1935 C section steel used for telecoms racking some parts cut / drill well and some spots are hard.
So mixed scrap in steel is nothing new.
I remember old 60's/70's jap cars rusting rather badly.
|Nick Hulme||02/01/2017 21:47:53|
|549 forum posts|
Type below your quoted text to avoid your text being displayed by the system as part of what you're quoting.
|Neil Wyatt||02/01/2017 22:30:01|
14107 forum posts
Or click on the top line then mouse click on the red arrow to insert a plain text line before the quote.
463 forum posts
Thank you for your polite response.
|Neil Lickfold||02/01/2017 22:51:07|
|459 forum posts|
There is a hot process that takes place at about 140deg C, you can buy the stuff from heat treatment supply companies. It has caustic soda in it, and other salts. I consider it safe to use if you take the appropriate precautions.
They will also give you the instructions for it's proper use. It does not work on stainless steels or steels with a high chrome content. But us great for MS or heat treated A2 tool steel and P20 that I know of, does not effect a steels temper as the 140C is below the steels tempering range.
|3631 forum posts|
60's 70's ? There were hardly any around then. There were a few about in the 80's but serious numbers came later. That's when they had steel supply limitations. Also near the start of oil technology getting well ahead of car engines and as far as the manufacturers were concerned lasting far to long.
There was a lot of crap mild steel around during wwII. My father told me that they had a name for it in toolrooms - park railings. As they were collecting them and resmelting them. There can still be crap pieces of steel about but sorry I don't think that has anything to do with recycling the stuff.
|Michael Gilligan||02/01/2017 23:22:15|
11609 forum posts
I'm surprised no-one has mentioned the FIAT story [myth?] discussed here: **LINK**
See post #13 if you can't be bothered reading the whole page.
123 forum posts
Off topic to the OP but on topic as far as recycled steel goes...
The most free cutting mild steel I've ever used came from some 're-purposed' plastic coated rods from a 1990s vintage clothes airer (and I still have about half a dozen 3ft lengths)!
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.