when not to use mild steel ?

[bodgeParticipant @bodge]

Posted by Neil Wyatt on 03/10/2016 08:43:21:

In my experience, very few stockholders use the euro-labelling:

**LINK**

I have never had any problems just relying on a a handful of EN steels.

Neil

Thats interesting, now we have black EN8, bright EN8, & engineering grade EN8.!

Any one know what S275 is ?

Edited By bodge on 03/10/2016 10:29:14

[Mark CParticipant @markc]

S275 is a structural grade general purpose steel. Can't remeber the other names for it but it is readily available in sheet, strip and bar.

Mark

[Nick_GParticipant @nick_g]

.

A few months ago when a steel plant was closing and there was outrage and examination as to the reasons why, one on the main causes was the price of the products not being low enough on the international market.

The Chinese for e.g. were placing very heavy import duties on what they termed as 'technical steel' from the UK. – What is or what category's of steels are classed as 'technical steel' ???

Just curious, Nick

[duncan webster 1Participant @duncanwebster1]

Posted by Michael Walters on 03/10/2016 06:39:28:

Posted by Hopper on 03/10/2016 04:55:44:

Just to bring it all up to date, leaded EN1a is now known as 230M07 PB, EN3 is 070M20, and EN8 is 080M40.

Couldn't they make it any more complicated than that? Or harder to remember?

This is why the EN system was created in the first place!

Michael W

EN tells you absolutely nothing, it's just a number. At least the BS970:1991 classification tells you something about the composition of the steel, 070M20 is 0.7% manganese, 0.2% carbon. If a stockholder doesn't understand a spec which is only 25 years old, perhaps you shouldn't deal with him.

[SillyOldDufferModerator @sillyoldduffer]

Posted by duncan webster on 03/10/2016 12:55:01:

Posted by Michael Walters on 03/10/2016 06:39:28:

Posted by Hopper on 03/10/2016 04:55:44:

…

…

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If a stockholder doesn't understand a spec which is only 25 years old, perhaps you shouldn't deal with him.

My early visits to my local steel supplier were more painful than they needed to be because I spoke "Metric, International Standards" and they spoke "Imperial – WW2 Emergency".

After they realised I was a serious repeat customer we began to communicate and I was able to ask the manager what was going on. "It's our customers "he said, "they don't understand or want anything new. I have to supply what they ask for."

I imagine up-to-date, bright-eyed, bushy tailed young chaps joining industry from college only to find they are working for traditionalists. These are the chaps who believe that anything since Whitworth was a backward step, evil, foreign, cheap, nasty and the reason we lost the Empire. Naturally enough, bright young men in such an environment will gradually fall in-line, eventually themselves becoming hide-bound just in time to correct the foolish modern ideas of the next generation.

Please tell me I'm wrong! I don't suppose Rolls-Royce work that way, but what about the small fry…

Dave

[Raymond AndersonParticipant @raymondanderson34407]

Technical steel ? hmm, Just another name for Protectionism I think.

bodge, Mark C is correct s275 is plain structural steel, ie UB's, UC's, SHS ect. That is the type most specified by Structural engineers in UK for buildings. . s355 is another Structural steel but stronger, specified for heavier loaded UB's ect. The numbers are to do with the minimum yield strength in N / mm ². There are quite a few other grades, but these are the most common used in the building industry. Also available in plates ect.

[MuzzerParticipant @muzzer]

Posted by duncan webster on 03/10/2016 12:55:01:

EN tells you absolutely nothing, it's just a number. At least the BS970:1991 classification tells you something about the composition of the steel, 070M20 is 0.7% manganese, 0.2% carbon. If a stockholder doesn't understand a spec which is only 25 years old, perhaps you shouldn't deal with him.

Possibly a bit extreme. The EN 10027 std is a lot more specific than the noddy grade descriptions at the likes of Metal Supermarket, like "EN8" or "304".

The actual description used on the drawings tends to depend on the customer, so in China the grades are often JIS (sort of the default), EN (European) or DIN (for German customers).

I expect the "technical steel" subject to duty will be defined on a (black)list but in practice I suspect this will basically mean high value, specialist alloys, rather than bread and butter commodity steels.

PS, the EN stds are copyright but they seem to be visible with little search effort.

Edited By Muzzer on 03/10/2016 13:49:39

[Anonymous]

Posted by SillyOldDuffer on 03/10/2016 13:28:20:

Please tell me I'm wrong! I don't suppose Rolls-Royce work that way, but what about the small fry…

I'm afraid you're wrong. No self-respecting "up-to-date, bright-eyed, bushy tailed young chap" would be seen dead in engineering. Instead they're in marketing with a nice new MBA, and leave all that boring, tedious technical stuff to the oldies.

Andrew

PS: I don't suppose that many of the materials that Rolls-Royce use are likely to be available from your average steel stockholder.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Nick_G on 03/10/2016 10:47:25:

.

…

What is or what category's of steels are classed as 'technical steel' ???

Just curious, Nick

It's the range of high-performance alloy steels used in power-stations, Aerospace, Defence and similar. It ranges out to include materials like Inconel, which has less than 10% iron in it, and isn't what I think of as 'steel' at all.

The West doesn't compete well with "BRIC" countries when it comes to mass-production of cheap commodity steels for car-making and construction, but we are still ahead with the expensive high-tech stuff.

It's hard to decode what the Chinese are up to but my guess is that they are simply trying to encourage their own industry to improve their capability to make high-end steels. Doing so would have commercial and Defence advantages. It's possible that the move is a military requirement intended to guarantee internal and export supply in the event of sanctions being applied by the West.

Dave

[mark costello 1Participant @markcostello1]

I thought Metrification was bad enough! I'll stick with 1018, 4140, and 12L15 steel thank You.

[AjohnwParticipant @ajohnw51620]

EN8M ( 212M36 ) Might be an interesting one to add. It's roughly twice as strong as mild steel and the yield stress is higher. It a free machining version of EN8. I was curious as some one mentioned it earlier. It's through hardening as well but wont be the same as silver steel in terms of cutting edges.

I think EN3 is the old case hardenable mild steel but I've seen comments that the none leaded free cutting can also be case hardened.

Steel used to be supplied by name or a supplier of good quality stuff. The numbers are more sensible but trying to find equivalents is difficult. Another very popular steel was KE805 used for all sorts of things but assuming I have the analysis correct lowish nickel chrome steel there doesn't seem to be anything similar other than 817M40T. There is also another version that is more tensile. 826M40 but probably more of a pig to machine. KE805 wasn't too bad.

John

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[MWParticipant @mw27036]

I fear this thread or topic may becoming one of those infamous "Sirens".

Edited By Michael Walters on 03/10/2016 14:29:56

[Mark CParticipant @markc]

KE numbers are specific to Kaiser Ellison (now defunct). Used to use lots of KE672 which was along the lines of GP (gauge plate).

Mark

[SillyOldDufferModerator @sillyoldduffer]

Steel is a generic term for an almost limitless of variety of iron based alloys.

According to Total Materia, their database contains the details of more than 230,000 grades.

Shock horror; it costs money to research the many varieties of steel that are available for industrial use. It's a good job we Model Engineers only have to deal with a few of them.

[AjohnwParticipant @ajohnw51620]

There is some one machining O1 here. Mixed results so suspect it could good be once machining is sorted. Needs skipping in places.

 

Not sure I would use oxy acetylene for hardening and also suspect he was turning at too high a speed.

 

John

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Edited By Ajohnw on 03/10/2016 20:41:06

Edited By Ajohnw on 03/10/2016 20:41:42

[Mark CParticipant @markc]

Speed looks too low and lacking feed rate/cut to me – chips are not taking the heat away (blue) and not breaking properly – not working the insert enough (it could be blunt also but can't see).

Oxy would be my preferred method for that job – you want the end hot in a hurry with the rest staying cool. O1 is oil hardening so agitated dip in oil is correct followed by tempering. Proof is in the eating or so they say, he seems to be cutting nicely in the final shot…..

D2 or A2 would also be OK for tooling. D2 will air harden as will the A 2 (A=Air hardening, O=Oil hardening, D=High Carbon & Chrome). D2 is very nice to machine and maintains good dimensional stability when heat treated. Best sent for vacuum heat treatment – comes back all nice and clean with a pleasing "precision engineered" look to it (if you did a good job machining it! ).

Mark

[Harold Hall 1Participant @haroldhall1]

Sorry Duncan for the confusion but I thought the later comments in my post would make my thoughts on the subject clear. So often we see on this and other forums, posters saying they are having problems machining some mild steel and can we help. Helping the questioner is then almost impossible as Mild Steel covers a wide range of steel grades. Therefore, if a supplier just offers Mild steel, as some do, my advice is to go and purchase from a supplier who offers steel to a meaningful spec.

To make this clear for those new to metalworking, the following is taken from the Metals4U website

"The term Mild Steel applies to all low carbon steel that does not contain any alloying elements in its makeup and has a carbon content that does not exceed 0.25%. The term “Mild” is used to cover a wide range of specifications and forms for a variety of Steel."

I will add again, my experience when making two spindles, one which was easy to achieve the required finish, whilst in the case of the second one, it was next to impossible due to using, unknowingly, two grades of steel Ever since I have always purchased to a known spec, not just Mild Steel.

Harold

[duncan webster 1Participant @duncanwebster1]

Harold, we agree completely, if you'd put 'mild steel' in quotations I'd have got it first time

AjohnW, yes you can case harden 070M20 (EN3), the stuff that is described as 'case hardening steel' is 080M15, which used to be EN32. It has a tad more manganese, but less carbon. The carbon content at the surface is then increased by the case hardening process, leaving the core soft and ductile.

[Neil LickfoldParticipant @neillickfold44316]

Video of making a boring bar, he is using the wrong chip breaker insert for that material. It should be coming off in chips, so the issues are either wrong chip breaker, wrong depth of cut and wrong feedrate. Being as it is not a really powerful lathe, he is taking small cuts and the tool geometry is therefore wrong for that particular material and job.

A finishing insert designed for small depth of cuts would have been a better choice. Most finishing insert geometries are for taking to 1mm depth of cut so are ideal for home workshops and lower powered lathes,

Neil

[AjohnwParticipant @ajohnw51620]

I mean to sort out an old Reeve's catalogue Duncan. It's about some where and thought they stocked EN3 for case hardening but not totally sure.

My interest in O1 stems from looking for a near equivalent to the very old higher carbon tool steels. I suspect that they were the equivalent of W grades which just aren't around any more. I've always been curious about the cutting edge sharpness that the can achieve. Fact or fiction ? Using oxy I notice that he went way past bright red heat and often that isn't a good idea. Well into the bright yellows from what I could see. I don't see any problem getting a section like that to the right temperature with a decent propane torch.

Decent steel – It's a pity that the old Reeve's have gone but on the other hand maybe the suppliers aren't around any more. From my TDO days I still have a booklet kicking around some where that I had to use. Branded material for specific jobs. Information gained over many years about what was best for specific jobs and no deviations allowed. Now that there are standards I suspect materials will vary 'cause there is scope for variations within them. It hard to know what companies used to get up to in this respect. They may have worked to much higher levels of precision and also at times might have added specific additional ingredients.

Oil quenching. The only thing I have ever used for that apart from once at home was a massive barrel of the stuff.

Cutting speeds – personally I don't always assume faster is better.

John

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[Mark CParticipant @markc]

Neil, could not see the chip breaker properly so can't really comment other than his insert has one and it does not appear to be working! I think the lathe is plenty big enough for that job (looks to be about Boxford size?) and he should be giving it a bit more, I think we agree on that.

John, You should still be able to get W grade tool steel – it is just a water hardening steel. Quench in water rather than oil. It will be significantly less stable during heat treatment and is easily cracked if you are not careful, an oil hardening or air hardening would be much easier to use depending on the application.

Mark

[Neil LickfoldParticipant @neillickfold44316]

It does have a chip breaker on that insert, but is the wrong one for that material choice. We have lots of inserts at work with different chip breakers for this reason. As one does not do all very well. The DCMT CCMT and the TNMG range of inserts also have the best range in chip breakers. There is a valid reason for the insert makers to have such a large selection of inserts. I do alot of O1 turning in both soft state and hardened state. It is essential on a cnc to get chip control. Long strings only lead to tears. Which is why I suggest for the home workshop the best compromise is to only get finish turning inserts and not the ruffing out ones.The radius to get is either the 0.2mm or 0.4mm radius inserts. Most home machines just don't have the power or rigidity to properly run a 0.8mm radius insert or bigger. For hard turning O1 I use either ceramic inserts or CBN inserts. Some jobs I have to use CBN as the ceramic does not come in a small enough radius. With Ceramic inserts run at surface speed of 90 to 180 m/min and a depth of cut from 0.05 to 0.5 or Ø0.1mm to Ø1mm at a feed rate of 0.06mm or 2 thou per rev. Ceramics wont take interrupted cutting.

Neil

[AjohnwParticipant @ajohnw51620]

I've sort of concluded finishing inserts are the best for me on a Boxford but it just happened that way as I didn't want to buy large inserts. They are ok on a mini lathe. I do wonder if max rad has something to do with rigidity of the whole set up though. I had no problem using the usual brazed tip large rad carbide tools on a Raglan. The ML7 I had which was pretty "loose" didn't like them at all. I've never tried them on the Boxford. They were also ok on brand new horrible combined mill lathe where the mill sits on the headstock. They had pretty obviously used a low tensile cast iron for making that.

I can't find anyone who lists W grade steels. O1 is no problem. I can ask next time I pass the place I usually get ferrous stuff from. It might not be the same any more though going on comments about the life of parts from a clock restorer. He reckoned it was something to do with the way the original iron was made. What he was suggesting was that parts that did last 100 years or more no longer did anything like that made with modern equivalents. He had a small stock of extremely old stuff and reckoned he had proved the difference with that.

Speed – I always bear in mind that lots of turning has been done on lathes that can't even get near 1000 rpm so if I have problems I always see what happens if I slow things down. I do get more torque that way as well.

John

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Edited By Ajohnw on 04/10/2016 11:19:36

[duncan webster 1Participant @duncanwebster1]

AjohnW,

from what I can glean, W just means water hardening. Give Carr's a ring on 0121 522 6789, if they can't help they will know a man who can. However if what you want is a small quantity of very hard steel, then Tubal Cain used to reckon that old files were harder than silver steel. You do of course have the problem of softening them before you can machine them

[AjohnwParticipant @ajohnw51620]

It's more to try for lathe tools Duncan than anything else. Curiosity. I'll bear Carr's in mind.

Tubal Cain's comment fits in with many others in different areas. That's why I am curious. I have used HSS's at work that will obtain a much sharper edge than what seems to be about now as well. All branded though. I have a fair selection of old branded HSS toolbits. Buy a lathe and they often come with lots if some one is giving up. Rather than use those I tend to buy new tool bits.

When I did the bearings on my ML7 is made a very small scraper out of an old 3 square file. It was extremely sharp. More like a razor. The one I made in training really needs hollow grinding again. Not sure if it's me or the grinder but I don't seem to be as dexterous as I used to be doing that sort of thing. Probably lack of practice. Now the weather is cooling my workshop is more likely to get up and running again. I need something small to grind that has suitable rests in that so suspect that will be the first job.

John

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