What is EN24 like to machine?

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What is EN24 like to machine?

This topic has 14 replies, 9 voices, and was last updated 23 February 2012 at 23:31 by M0BND.

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13 January 2012 at 22:26 #81985
Ian P
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@ianp
I am contemplating turning and screwcutting a male thread 50mm diameter(pitch 3mm) on EN24 steel.

In the past I have screwcut small stuff mostly in non ferrous with no problems, for this project I would get a carbide tip with the correct thread form but I am wondering what sort of finish I can expect and whether something like this is well within the capabilities of a 5″ Boxford

I have not knowingly used EN24 before but have modified numerous HT bolts, are they a comparable grade?

Ian
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13 January 2012 at 22:26 #29451
Ian P
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@ianp
13 January 2012 at 22:54 #81991
Sub Mandrel
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@submandrel
I’ve machined it but only a few times.

EN24T will be fine, but make sure it is ‘T’ or tempered, not in the hard condition.

Tools need to be sharp and take it easy and it machines better than silver steel.

Neil
13 January 2012 at 23:34 #81996
John Stevenson 1
Participant
@johnstevenson1
Neil, I think you mean EN24M the M stands for machinable.

Ian it does machine nice, on carbide try to go as fast as possible and neat cutting oil.

John S.
13 January 2012 at 23:51 #81999
JohnF
Participant
@johnf59703
Ian, I use EN24T quite a bit but in smaller sizes, it machine’s easily and you should have no trouble with screw cutting it and its well within you lathes capacity. I have cut threads 2 inch dia on my Myford S7.

With a fairly coarse thread 3mm, it might be wise to set the compound slide to 30 deg even though you are proposing to use a full form tip. Take a very small straight cut a the end with the cross slide to get the full form.

Regards John
14 January 2012 at 00:37 #82001
GoCreate
Participant
@gocreate
Ian

For En 24 the added suffix indicates the material heat treated condition.

En24 ‘T’ condition is hardened and tempered and quite tough to machine, in my experience it’s a case of reduced speed, small depth of cut and adequate feedrate when using a light machine. Carbide tools are best, you can go to high speed very fine cuts and feeds for finishing however I find good finish is relatively easy to obtain at slower speeds and plenty cutting oil.

In ‘T’ condition Its tensile strength and hardness are in the range of grade 8.8 to 10.9 high tensile bolts. Most high tensile bolts will be either one of these grades, socket head cap screws are generaly of a higher 12.9 grade.

If you have been machining high tensile bolts then EN24T wil be similar.

En24 is commonly available in annealled conditon (M???) and heat treated ‘T’ condition.

As John S indicates, ‘M’ condition is easier to machine than high tensile grade 8.8/10.9 bolts.

Nigel

Edited By tractionengine42 on 14/01/2012 00:43:32
14 January 2012 at 07:35 #82008
Raymond Anderson
Participant
@raymondanderson34407
Ian,

EN 24 in the “T” condition is the easiest to machine as it has the lowest tensile strength of the other conditions,which are U , V , W , X , and Z. [ I have never heard of a M condition ] I get all my EN24T from my brothers employers and EN16T, and I love machining both types as the finish is super I find them [EN16T ,EN24T] to be very clean materials to work with. I can’t comment on Depth of cut or feed rates as I don’t know the machine involved.

Regards,

Raymond.

traction engine42,

I don’t wish to appear argumentative but, EN24T is not hardened, it has the lowest hardness of all the conditions.

Regards,

Raymond.
14 January 2012 at 09:52 #82014
Ian P
Participant
@ianp
Thanks to all that have replied. From what I have learnt I now have no trepidation in making the parts I want. Regardless of what conditions it may be available in, most of the ME suppliers sell EN24 as EN24T so that is what I will get.

I presume/hope that I will not need to subsequently heat treat it for this application which is, the threaded part of a classic car ‘Knock on’ (or centrelock) hub.

Ian
14 January 2012 at 10:45 #82020
Raymond Anderson
Participant
@raymondanderson34407
Ian,

You are correct in that model engineer suppliers usually stock in in the “T” condition as that is the most readily machinable grade. So have no fears with it, just be sensible with your depth of cut and feed rates and you will have a steel that finishes just a treat.

Also, if you plan on using it often, then the following inserts “WALTER, WPP01” have a very good tool life.

Regards,

Raymond.
14 January 2012 at 11:10 #82023
Steve Withnell
Participant
@stevewithnell34426
I’m quite confused now. Is EN24T tempered and hardened or just tempered for machining before hardening?

I cannot find any references via Google to EN24M , though I can find an EN16MT which has a better machinability index (39%) than EN16T and EN16T has the same machinability index as EN24T (29%).

I find I can get a really good finish on the EN16T I’ve played with, provided I go hell for leather with neat cutting oil (it’s the only cutting oil I have), but this makes taking short cuts (say 4mm as a slot in a bar 10mm deep) to close tolerances and getting an immaculate finish a really big challenge.

Steve
14 January 2012 at 11:59 #82026
GoCreate
Participant
@gocreate
Hi Raymond

Other than in the annealed condition En24T is the easiest to machine in the range T to Z.

All the conditions T to Z are hardened, they are given different tempers to achive different mechanical properties, T condition has the highest temper and therefore the easiest in this range to machine

I have not heard of En 24 M,

I have used En8M which is great to machine but is a lower strength material.

Nigel
14 January 2012 at 14:45 #82035
Raymond Anderson
Participant
@raymondanderson34407
Nigel,

Sorry about the confusion on my part, I thought you meant that the EN24T was

” Hardened” as in “you need CBN to machine it” so my apologies.

When I asked the brother about EN24M ?? he had never heard of it and he uses the 24 almost every day, and when he’s not using the 16/24, it is another powder puff material Inconel 718

Yes, EN8 M or DM is nice stuff although I don’t get so much of it.

Regards,

Raymond.
23 February 2012 at 17:26 #85568
rakesh bhargava
Participant
@rakeshbhargava18256
Hello Raymond,

I am new to EN24 and Heat Treatments. I need to heat treat EN24 to Z condition. Can you tell me how is Z treatment done? What is the meaning of U V W X and Z Heat Treatments?

Regards,

Rakesh Bhargava
23 February 2012 at 17:48 #85571
GoCreate
Participant
@gocreate
Hi Rakesh

Here is some info on heat traeted conditions of EN24.

Can't realy give any specific help with heat traetement but I guess you will heat to cherry red, soak at that temp for a while, quench in oil, temper to a light purple. This might help.

444HB converts to 48 RC

Nigel
23 February 2012 at 23:31 #85607
M0BND
Participant
@m0bnd
817M40T – EN24T. Quite a tough form of steel, however, don't be afraid of it! It's lovely to machine, you won't get a perfect finish (maybe 0.8 or N6 surface finish) but with correct speeds and feeds, you will be very pleased with the results you get!!!

Have a look at http://www.steelexpress.co.uk/engineeringsteel/EN24.html

Andy.
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