EN32B Steel

Clive, from what you write it's starting to get political ! Better off out the EU and away from EN steel and back to British Standard ( BS) specifications. All said a bit tongue-in-cheek really, with a bit of truth in it! Another plus for Brexit perhaps?

Chris

Reflecting on my previous post I reckon its time that a small committee of folk who know about such things were got together and asked to decide on a Model Engineer / Home Shop Worker friendly selection of reliable steels using modern designations. Although I like BS 970:1991 it is obsolescent so BS EN 10277:1999 and Euro Norms would be better. Even if they do look like gobbledygook to the uninitiated like me.

Important that the selected steels are readily available, machine well and are tolerant of analysis, condition and supplier variations so they behave in the expected manner whoever you get it from. Beginner friendly too as proper tool shape, speed and feed recommendations could be published and be certain to work.

Leaving aside the silver steels, gauge plate and similar steels I figure we need :-

1) A basic easy to machine steel that gives nice finish with little trouble. EN1A leaded substitute.

2) General purpose steel strong enough and hard enough for most jobs.

3) Something safe to weld.

4) Something that will case harden with the compounds currently easily available.

5) Something for high strength duties. EN19T, EN16T, SAE 4140 substitute. Folk like us have no business messing with things where tensile range T isn't enough. Tends to be serious engineering territory.

I'm no fan of leaded free cutting steels in the home shop given the (lack of) materials control systems. Too easy to pick up a handy bit and try to weld it. I gather modern inclusion modification processes produce steels pretty much as easy to machine but still safe to weld. If it could also cover requirement 2 life would be really simple. Only 3 steels for average user to keep track of. Strong stuff, case harden stuff and "does everything else". Perhaps a supplementary list for advanced requirements.

Clive.

ChrisH

EN numbers are British.

Initially codified as the Emergency Numbering system in WW2. Previously steels were, mostly, supplied under manufacturer specific names for different alloys. Matching name to specification & performance from multiple suppliers must have been challenging. Final codification was BS 970:1955 by which time the whole thing was falling apart due to too many specialist steels with nowhere to put them. Hence the A, B, C, M et al suffixes which often hide quite major variations in performance.

Clive.

Edited By Clive Foster on 18/12/2017 23:41:47

That's a really good idea Clive. But I think the problem may be deeper than that.

Buying metal at my local emporium I find they don't speak modern. Instead, 'because it's what customers want' you have to ask for steel by EN number. The reason is custom; steel has been ordered that way since 1941 and anything different must be cheap nasty tat.

Unfortunately, because nobody makes steel to the long obsolete EN specifications, you get supplied with a modern equivalent. As there are thousands of modern steels available it's properties will be similar to EN, but not necessarily identical. You don't know what it really is, and could get something different when you buy more. No wonder there are disappointments. It might be another reason why small users often find 'quality' problems in their tiny purchases whilst far fewer problems are reported by bulk industrial users. You don't often hear of industry grinding to a halt because of faulty steel.

So step one would be the selection of a basic list of modern steels suitable for hobby engineering exacly as Clive suggests. Step 2 may be harder - finding someone to supply it when multitudes of traditional buyers insist on EN. I suppose the internet should make it possible.

Dave

One problem with a list like that is that having one general purpose steel will give you difficulty when you come to buy in different sections.

General purpose round is usually EN1A (230M70) but if you want a general purpose flat or square bar that is most likely to be sold in EN3 (080A15) or if you wanted hex then the usually stock is EN1A Leaded (230M70PB).

There are a few exception where you may get EN1A square for example but the choice of size is less particularly if you still want imperial sections.

A look through Parkers bright steel selection in both metric and imperial gives a good idea of what is available from a large stockist if you click the product matric for the chosen section it give size and metal types and a link to the paint colours is there too. Smaller stockholders will keep less and ME suppliers even less choice.

Hello Dave.

I cannot say that I have read all of the report that you linked in your post, however as far as I could see the report relates only to non metallic inclusions, and makes no mention of possible problems with metallic inclusions or give steel a clean bill of health on that count. Please correct me if I am wrong. It is interesting further down the report that Ravenscraig seems to come out with a fairly clean bill of health.

I do not think we all are imagining that there is a problem with the currently supplied steel.

Re, parts of ball bearings etc. in steel. I cannot say I have seen that. However, in a former life I was persuaded against my instincts to injection mould some recycled polypropylene. Part way through the first bag I discovered a large broken spring which had fortunately attached to a ring of magnets in the base of the hopper If it had reached the screw it would have caused some very expensive damage. I learned a lesson that day, using outside sourced recycled material could be a very big mistake. kind regards Anna

Slightly off topic....I am old enough to remember he railings and gates being removed for the "war effort" This was followed by a horse and cart collecting mums spare saucepans, the rumour was for spitfires!!

Some years later in my national service I found myself blasting away with a 3.5 inch rocket launcher(don't dare to call them a bazooka) punching holes in defunct military tanks on Luneburg Heath, in Germany, it did occur to me at the time that they might have been made from my parents old railings.

I guess that quantity rather than quality was the order of the day then...............perhaps it still applies!!!

Hi Anna,

Yes, the report is about non-metallic inclusions. I found it (and similar material) while looking for evidence of metal objects found in steel. I didn't find any evidence of those.

The report's significance is that it explains the presence of hard inclusions without requiring a ball-bearing or a lump of HSS to somehow survive unmelted in a furnace heated well above steel melting point. A huge amount of energy is needed to react out impurities and a big furnace can process as much as 30,000 tons of steel at a time. Although I feel metal inclusions are unlikely to survive that environment, the process damages the furnace and subsequent handling can also introduce problems.

Though I'm sure hard spots are a real problem I doubt they're caused by incompetent manufacture. Nor are they new - complaints about steel quality are as old as the hills. Ordinary cooling and rolling etc. can also cause problems. Perhaps this cause of hardness is even more likely than an inclusion - it's difficult to cool a large lump of metal at the same rate throughout. Normalising fixes it, a process that's been about for centuries.

When it really matters, say making a nuclear reactor's pressure vessel, steel-makers can guarantee their output to high standards. Careful selection of materials, extra careful chemistry, clean processing with an electric furnace full of Argon, and elaborate testing are all effective. Shame about the cost!

It's far more likely for unwanted objects to turn up in other recycled materials (and in food!) The processing isn't very intensive and might include error-prone hand picking. Or corner cutting to save money. When it really matters you have to be careful what you buy and check everything.

Dave

Dave,

Thank you for your reply.

Just out of interest over the past few days I have been machining some steel (en3b) and have found what look like very fine hair line marks (fissures?) in the machined surface very similar to those shown in the report just discussed. I cannot say I have ever seen that before.

Regards Anna

Clive - I did say it was tongue-in-cheek, it was playing with letters to achieve a comment. I am aware of the origin of EN numbers.

What would be good is some standardisation of what all suppliers call each product. Some will say EN1A, others will only answer to 230M70 for example, both are arguably the same product.

I also appreciate that odd hard bits can and do get found in all sorts of types of steel at random intervals and that the problem is a very old one. I can never legislate to avoid ever getting a bit of steel with a hard bit in it, but I can try and ascertain what other folks do to get round the problem and use that knowledge to help myself deal with the problem when I experience it, which is what this thread is all about.

Chris

Lots of model engineering suppliers quote 'GCQ' when asked what steel they sell. this means 'I've lost the cert, or I didn't understand it so I threw it away'

My local stockholder have a computerise inventory down to the stubbiest of short-ends, but ask for 230M70 19mm and you will get 3/4" EN1a - in a three metre length, of course...

Neil

I use a very good local steel merchant, I tell them what I want the steel for and they tell what I need. Some times it's an EN number sometimes it's a BS number. Best policy is find a merchant you can trust and don't worry to much about the cost.

I used to have a very good steel stockholder (Macreadys in Rugby), but after a couple of takeovers, their replacements only stock a limited number of alloys and have a minimum 1 tonne per size policy. I used to be able to buy full bars of all the normal alloys and heat-treats (EN1A, EN1APb, EN3, EN8, EN16T, EN24 and EN24T) and less-than-full-bar when the diameters got up to 4". It's annoying, since they are only a mile away from home, but the downsizing of my (ex) employers in the town from a total of 10,000 to 1,000 over the last 35 years might have something to do with it...

Now I use Parker Steels (who are over an hundred miles away) and still try to buy minimums on one bar of any size. Ok the kids might have a selection of steel stock to use/dispose of when I go to meet my maker, but I can't see the point of buying the odd foot of steel unless that length is already too heavy to lift easily. Steel gets an awful lot cheaper if you can buy enough of any size to keep you going for the rest of your planned lifetime.

Back to the point:- I have met up with work hardening when not cutting aggressively enough or cutting an unknown alloy. I have wrecked carbide milling cutters in black mild steel plate when using them for work that a bandsaw was better at. But I haven't, yet, met a hard spot in a full bar of a known alloy. Some of the bars that I've bought have shown signs of being at the start or end of the run. Those bits are obvious and can be discarded.

Edited By Mark Rand on 20/12/2017 00:45:12

Or sold off to Model Engineers on ebay

Ooooh errrr! I had chance yesterday for shed time, so lite the fire in the shed stove, got it going well on smoke-less, chucked the tool holder with the hard bit in, threw some more coal on top, saw it a wee while later all - including the metal - very much glowing nicely (very) red and left it to burn through and cool down overnight. This morning I pulled the metal bit out the ashes and; Oh my word, I didn't expect this: - see photos below.

I chipped all the scale off and revealed what could be expected - the metal underneath was very rough. Set it up in the mill and tried a facing cut off one side with a flycutter and promptly blunted it, so, unwilling to sacrifice another milling cutter it now looks like I have another useful door stop. Another item now on the next metals order!

Chris

Might be a silly question, but here goes. To carburise something you bury it in carbon (kasenit, button dust, sugar etc) get it red hot and keep it there whilst the carbon diffuses into the surface layer. To anneal something in your coal burning stove you cover it in carbon and get it red hot......... See where I'm coming from?

Yes Duncan, that did occur to me after, and not a silly question. Perhaps it might have worked if I had covered it in SS shim, which I have, before placing in the coals, or if I'd been able to fabricate some means of holding it above the coal. That process not thought through before I went for it!

Both alternatives have given me fuel for thought for the future though. What it has proved is that in my stove I can heat a really considerable lump of metal up to red hot glowing temperatures and hold it for a while, hours, if necessary, which I didn't think I could do, so that is progress in one direction. I had sort of given up on the lump anyway really. Now I know I can do it, the next stage is refining the process to get it to work for me, whether either annealing or case hardening. Wrapping an item in SS shim packed with carbon of whatever extraction and 'cooking' it in the fire or arranging a removable rack to place objects to be annealed or case hardened on is a reality to explore! Quite like the rack idea.

Had I an electric furnace all would have been easier but I don't now the money to buy one, even if I had ever seen one advertised which I haven't, like where do you scource cheap electric furnaces except perhaps ebay?

Chris

maleable iron electrical fitting or other steel box would be the traditional approach, SS shim is too valuable, and prone to leakage to use as wrapping paper.

Hint Neil, article on making an elctric muffle needed.

Re the carbon comments, this is why it is always suggested to cool as slowly as possible. If it does take on carbon and you take it out the fire and quench it that is just like hardening with kasamite, leave it too cool slowly and you end up with steel in it's unhardened state.

Might have been worth pickling the part to remove the abrasive scale before you tried to cut it again.