En24T (or equivalnet) in plate form ?? 1

[Milkboy]

Hey

I specified some tool holders to be made from En24T
(about 100-120 kg each to give idea of size)

The components in the toolholder are basically plates
and the sub con mach. shop said En24T was only available
in Bar form. Doh ! as if often said in these instances.

I choose En24T as a robust Stainless.
I was initial stuggling in selecting a material as the guy
in the job before me had listed 'Fork Steel' as the material

Can anyone recmmnd an equivalent (or similar) to En24T available
in plate format

350 x 380 x 50 thick
350 x 380 x 20 thick
are my basic sizes

TIA


-
Milkboy

 

[andyenergy]

Err... are you sure you mean En24T as in BS970 En24T?

According to my copy of BS970 (1955) En24 is a 1.5% Ni-CrMo steel. C 0.35/0.45, Si 0.10/0.35, Mn0.45/0.70, Ni 1.30/1.80, Cr 0.90/1.40, Mo 0.35% max, S & P 0.050 ,max.
Condition T (with a limiting ruling section of 6&quot gives a min yield of 44 Tsi and a min UTS of 55 tsi.

This definitley isn't a stainless steel. Its is a direct hardening alloy.

Current BS 970 equivalent to En24 in condition T would be a 817M40 material but as you point out, BS 970 is for bar material. Equivalent plate material would be as specified in EN 10083-:1991 where 817M40 (a peculiarly UK grade) is given as (name)34CrNiMo6 (number)1.6582.

Unfortunately I'm not particularly familiar with this standard and I suspect that in order to meet your mechanical properties you may have to organise some heat treatment.

Typical properties for a flat product (i.e plate)34CrNiMo6 in the thickness range are: Yield 800 N/mm2, UTS 1000 - 1200 N/mm2, Rin Area 50%, Elongation 11% KV min 45 J.

Hope this is useful anyway.

Andy

 

[Milkboy]

Thanks Andy

I really having a bad time with this

The drawings were labelled FORK STEEL which is SAE15B35H (MOD) Carbon Manganese Boron

Could the tool holders be made from this ???
Did the guy who designed the holders simply cut
some Bar Stock of 'Fork Steel' in house and send it out for manufacture ??
Nobody here remembers !

Im not well up with materials as you can see, so when En24T was mentioned I assumed it was used in the past
and someone did remember.

After your post, Im not convinced En24T was used here.

Im basically looking for a 'robust' Stainless Steel
which is easy to machine, cheap to buy, and is in Plate form (if this exists)

Im especially stumped as the mat. manual form my previous company list BAR and nothing else so I cant even use this as a start point.

Ta




-
Milkboy

 

[TVP]

Do you really want the steel alloy to be a stainless grade? Neither of the alloys that you have mentioned (EN24T, 15B35 Mod) are stainless steels, i.e., having a minimum Cr content of 10.5%. If want a stainless steel grade similar in strength to a quenched and tempered steel (EN24T, 15B35 Mod) then you need a martensitic or precipitation hardening grade like Type 420 (martensitic) or Type 630 (PH). You can obtain more information from producers of stainless steels like AK Steel, Allegheny Ludlum, etc.

http://www.aksteel.com/markets_products/stainless.asp

http://www.alleghenyludlum.com/

 

[andyenergy]

Whoaahhhh... I think you might be getting a bit confused here. Lets start at the beginning again.

I pointed out that En24T is not a stainless steel -it's some form of tool steel, which is what I would expect in your application.

I'm afraid that I'm not an expert in dies and materials used for hot bending/work so any advice I give can only be given on the basis of a fundamental understanding of these types of materials.

En24T (your fork steel) is a direct hardening steel. See the description in the following link.

http://www.metserve.co.za/Extra/EN - Materials.htm

SAE15B35H is indeed a Carbon boron steel and is capable of through hardening. It is recommended for dies and the like. Here's a link that gives some information.

http://www.corusconstructionandindustrial.com/corus/index.jsp?pageID=152

In your earlier thread

thread330-83917

you recieved some good advice on various other tool steels and the reasons for choosing specific types. It seems to me that richardbuss was offering data on both those types and the advice that was given by him and TVP were sound.

The actual hardness that a material is supplied to is just one factor (usually to prevent premature wear). Other factors are resistance to thermal shock, strength, risk of overtempering at operating temperature.

You do not want a stainless steel. Stainless steels are no good for this type of application.

You want a tool steel of some description. Unfortunately it is not possible to be specific about what grade you need because as mentioned proviously in the earlier thread it will depend on the temperature your dies/tools see, what the actual operation is and possibly other factors as well.

It may be that En24T is prefectly acceptable (as well as SAE 15B35GH or ALZ H13 or D2). I don't think we can tell you precisly what you want.

This area is quite complex and I know it's difficult when faced with apparently conflicting information and not having the background as to why earlier decisions on material choice were made. Sometimes incorrect choices have been made in the past.

I suggest that you contact either Corus (if you're in the UK) or another steel producer/supplier to determine what your needs actually are based on what you are trying to do with it. Or, if you are happy that En24T fits the bill, ask your supplier to suggest/provide a similar performing material in an alternative product form, then check what they propose. You may have to heat treat after machining or may be able to machine the supplied material if it meets your service requirements.

I hope this is useful.

Andy

 

[andyenergy]

Good point TVP - it took me so long to reply you got there before me.

I agrre that none of the steels were stainless and I was so focused on hardenable alloys I overlooked the martensitic/precipitation hardening grades!

I think for milkboys application (based on his earlier thread) is for a tool that is to be used in hot forming of something.

 

[Milkboy]

Thanks Guys

I really appreciate your feedback especially when I must seem so vague and uneducated !! :O)

The tool is ALZ H13
its the filling in a round sandwich that hot bar
is bent around

The Holder has a H1 wear plate above and below
the 'filling' of larger dia

Then I have the UNKNOWN holder material
above and below the said wear plates

En24T has been mentioned for this Holder
material as has 431S29T along with S690QL1

P20 has just been thrown up aswell

I think this IS the material but my current
form suggest I should offer this to the forum
for comment

Ta

-
Milkboy

 

[Milkboy]

Thats H13 wear plates not H1

-
Milkboy

 

[andyenergy]

One last go at this before I give up.

In the course of this thread you've mentioned no less than 7 grades of material.

Just to fill you in on the grades you mentioned in the last post:

431S29 - a martensitic stainless steel

S690QL1 - high yield strength structural steel - quenched and tempered Specified in BSEN 10137-2 Plates and wide flats

P20 - a hardened and tempered mould steel giving a hardness of Rc 30-33

If it's the holder you are intertested in rather than the tool itself the I presume that it doesn't have to have any particular wear properties. The holder could therefore be En24T, but as this doesn't come in bar form, then the equivalent EN 10083-:1991 817M40 would be suitable.

As I mentioned before, I'm not entirely familiar with forming machinery and the properites required for various components, but I would hazard a guess that the tool holders don't need to be anything better than a strong steel to take any stresses
associated with the forming process and the transfer of loads from the forming tools where they are attached to the tool holders.

Why don't you just send of the tool hoders to a testing lab, get it analysed (all you need is a flat surface somewhere) then make your next set of holders from a similar material that is heat treated if necessary.

Good luck

Andy

 

[PeterCharles]

For reference EN24 is a hardening and tempering steel. My 1955 (oh how I like old publications)copy of BS970 lists it as being suitable for conditions "S" (50/60 Ton/in2) through to "Z" (100 Ton/in2) according to heat treatment. In the UK it is widely available in "T" condition (55/65 ton/in2) which has a limiting ruling section of 6". Normally it is in round bar form. We still use it for shafts though we now call it 817M40T,(but everyone knows it as EN24T). On some test fixtures I once used it in condition "Z".