Different Steels

[ChrisHParticipant @chrish]

The most readily available steel seems to be 230M07, or EN1A. Oft quoted for certain parts is steel 070M20 which is claimed on one website to be the same as 080a15, which seems strange. However, my query is, if 230M07 is used instead of 070M20, what are the likely problems and drawbacks? Will anyone notice?

ChrisH

[ChrisHParticipant @chrish]

[Keith LongParticipant @keithlong89920]

According to Tubal Cain’s book “Model Engineer’s Handbook” 070M20 used to be called EN3 and has a 15 – 20% higher UTS than 230M07 or EN1A. So if the part you’re making is highly stressed then yes you might notice when it breaks sooner. Personally if I was designing a part that was highly stressed then I don’t think I’d be using either of those steels anyway. 070M20 seems to be regarded as a general grade of lowish carbon steel, whereas 230M07 is a free machining low carbon steel.
 

Keith

Edited By Keith Long on 27/01/2011 22:53:29

[Martin WParticipant @martinw]

Hi

 

First of all Keith please accept my apologies as I sent you a table of steel properties by mistake . Chris I have sent you a pm with a table of the properties of various steels with both the EN and BS numbers.

 

Cheers

 

Martin

[Keith LongParticipant @keithlong89920]

HI Martin

No need to apologise you’ve just saved me the effort of writing this out for myself, it very useful to have the properties brought together like that.

That table is very useful, could do with a wider circulation as this question keeps on cropping up and with the numerous classification systems for steels it isn’t easy to find your way around the metals especially if you are a relative newcomer to this game.

Many thanks

Keith

[David Clark 13Participant @davidclark13]

Hi There

Any non copyright tables or information can be loaded to the website.

We have to do it, you can’t, so contact me first and we can look at including it.

regards David

 

 

[Gray62Participant @gray62]

There are a number of tables of steel properties to be found through Google, one such is here.Steel Grades

[macmarchParticipant @macmarch]

The main thing to remember is that 070M20 (EN3A) is weldable. EN1A can be but it is likely to crack. EN1A is sometimes supplied as EN1AP, this has lead added to enable easy machining on auto’s and cnc lathes. EN3A is also better for lightly stressed parts. 080A15 is best regarded as the equivalent to EN32, a case hardenable steel whereas 080M40 is about EN8, a heat treatable steel.

 

cheers Ray

[macmarchParticipant @macmarch]

This site is useful without being too technical.

 

Steel comparisons

 

Ray

Edited By macmarch on 28/01/2011 20:45:24

[John Stevenson 1Participant @johnstevenson1]

I wish they would stop with all this BS 970:1991 rubbish.

 

I go to all the trouble of getting the right grades, ring the supplier up and ask if they have any 70mm round 835M15 on stock and the guy says.

“Oh you mean EN39B ?”

 

They ship it out and it says EN39B in large letters with 835M15 in small letters in brackets.

 

I mean who can remember all these XXXMXX numbers, they don’t even follow a logical standard, at least with the EN numbers the larger the number the tougher they are.

 

John S.

[Gray62Participant @gray62]

BS 970 has been generally superseded by European based standards – where will it all end?

BS970 Numbering system explained

The BS970 code number is constructed as follows;

a) The first three symbols are a number code indicating the type of steel:

000 to 199 Carbon and carbon-manganese steels. The number represents the manganese content x 100

200 to 240 Free cutting steels. The second and third number indicate the sulphur content x 100

250 Silicon Manganese valve steels

300 to 499 Stainless and heat resisting steels

500 to 999 Alloy Steels

b) The fourth symbol is a letter code .

A The steel is supplied to a chemical compostion determine by analysis of the batch sample.

H The steel is supplied to a hardenability specification

M The steel is supplied to a Mechanical Property specification.

S The steel is a stainless steel

c) The fifth and sixth symbol is a number is the actual mean carbon content x 100

In addition to the above coding a condition coding may be applied. indicating the tensile strength range after heat treatment. This is used in conjunction with a limiting section designation.

So that makes it all crystal clear doesn’t it

[John Stevenson 1Participant @johnstevenson1]

Posted by CoalBurner on 28/01/2011 23:39:29:

So that makes it all crystal clear doesn’t it

 

 

 

 

NO.

 

John S.

[KWILParticipant @kwil]

Its no different when you go to the timber yard, 3 metres of 50 x 25 you say which draws the call “10 ft of 2″x 1” !!! So what.

[Ian S CParticipant @iansc]

Kwil, if you get your order in dressed timber, it will actually measure about 45x 20, they quote the undressed size, I pesume its the same in UK.

For a lot of stuff it quite OK to use hot rolled/ black steel, its got less internal stress than cold rolled, and its usually cheaper. Ian S C

[Martin WParticipant @martinw]

Hi

 

With regard to the plethora of steel type specifications I would rather have that than what preceded it prior to circa 1938. Then steels made by different manufacturers, as I understand it, were unique to that particular company. In order to get some consistency in the market the government of the day decided to try and standardise the production of steels and introduced the EN or Emergency Numbering of steel types. Since then steel production has been refined and the number of different steels being produced has increased and the basic EN system itself needed refining hence the BS standards.

 

Now we are part of Europe, and all that goes with that, this has come under the control of the European standards with its classification system. The unfortunate part of this is that now we are back classifying steels with a code that starts EN , roughly translated as European Norm.

 

Simples NO , but better than pre 1938 YES .

 

I expect the historians and purists to make corrections to the above and welcome having the true facts presented rather than my rough account.

 

Cheers

 

Martin

[KWILParticipant @kwil]

You are correct of course Ian, sizes are always as sawn. agree regards hot rolled/black steel, but unless it is to remain round always relieve those internal stresses by use of heat and a slow cool. Even flat plate used flat will move if you shape it.

[Martin WParticipant @martinw]

Ian

 

Yep timber is the same here as well, comes sawn to roughly indicated size but if planed then its under size. Though some outlets will now give actual size after dressing but this is usually smaller than the equivalent sawn. I suspect its because the DIY market is full of numpties who read the label and don’t measure .

 

Cheers

 

Martin

[Nicholas FarrParticipant @nicholasfarr14254]

Hi,

 

as far as I am aware, that because we in the UK are part of the European Union, BS numbers are no longer valid, unless there is no Europian equivelent standard.

 

i.e. there is no Europian standard for Whitworth screw threads, so the BS standards can still be used.

 

I don’t know if there are steels still being produced that are not covered by Europian standards.

 

This doesn’t seem to stop BS numbers to be quoted though.

 

Regards Nick.

[John Stevenson 1Participant @johnstevenson1]

Martin, with all due respect who here is working with pre 1938 steels.?

I know of the history of why and how the EN numbers were founded and it was a good move but after 1940 when the EN series was standardised that is all anyone except possibly a very, very few who were working at this time knows, the original EN numbers which whether or not we are in the EC, EEC, Europe or whatever are still valid to most, even the steel suppliers.

 

John S.

[John Stevenson 1Participant @johnstevenson1]

Same here as Ian, hot rolled and I have been doing some ‘tests’ on it and formed a conclusion that may be right or wrong but it works for me.

What started it was 90mm bright comes in 3 metre lengths and costs about £140 per length, I know this is not model engineering but bear with me.

As this job wasn’t critical I decided to go with hot rolled which is basically EN3B, a general all round steel. 90mm in hot rolled comes in 7 metre lengths for £160, £20 more for more than double the quantity, no contest.

However hot rolled has a tendency to rip and tear, especially on threading. I have some 16mm here, bought for window bars and it’s not nice to turn.
The 90mm turned very well and with a new tip the finish was like a mirror, so I got thinking, at what point does hot rolled NOT turn well? Next job was some bits in 25mm so I ordered a bar of 1″ and it machined well, then ordered 20mm and no problems with this.

So at some point between 16mm and 20mm the machining characteristics of this material change, my conclusions are that the larger the piece the longer it takes to cool and so affects the machining characteristics.

A job in the future will be to send a piece of 16mm over with some other parts to the heat treat shop and have it normalised, then try machining it.

John S.

Edited By John Stevenson on 29/01/2011 17:50:28

[Ian S CParticipant @iansc]

I treat hot rolled in a similar way that I treated pine when I was wood turning, ie if you can make a good job of it, you can turn any thing with a good finish, SHARP tools and get the feed and speed right, I find HSS seems to work best. Yes it some times tends tear a bit, especially when threading, mainly with external threads if the die’s getting on a bit, I find that silver steel can get a fairly rough finish, pehaps if I harden it then I’ll have a round file. Ian S C

[KWILParticipant @kwil]

Some suppliers will sell you “best commercial quality” steel which they say is EN3B, all I can say is that it is not. I stick to the good supplier who sells you good consistent quality material, anyway as I said above , if in doubt I normalise it.

[Ian S CParticipant @iansc]

The supplier might say “best commercial quality” and say EN3B, but the manufacturer would say all his steel is the best quality.

One steel that can be a bit of a pain to machine is water pipe. IanS C

[ChrisHParticipant @chrish]

Thanks to all for your input and advices here – much appreciated.

 

Is there a table that shows the different compositions of all the different steels? It would be interesting to compare say EN1A and EN3A.

 

Chris

[61962Participant @61962]

Chris,

 

Have a look at this website. You should find what you need.

 

/www.roymech.co.uk/Useful_Tables/Matter/Strength_st.htm

 

Eddie

[Author]

Posts