Evening all,
I have been sent a piece of 'mystery metal' to make some heli parts
from.
The sender told me its 6Al4V Ti, which by all accounts is a PIG to
work
with. However it isnt... which leads me to suspect its not Ti but a
7000
series Alloy.
Its about the same density as ally, just by hand comparisons, and its
not
magnetic.
about the only simple test I can think of is to just melt an offcut
(Ive
already made some parts). If I can melt it before it gets red its ally
of
some sort, if not it might be Ti, and people are 'bigging up' how hard
it is
to machine....
any other simple tests anyone can think of or comments?

cheers

Dave

"dave sanderson"  wrote in message 
news:75c64664-2927-4cfd-9c0a-b33068ca11e1@a70g2000hsh.googlegroups.com...
> Evening all,
> I have been sent a piece of 'mystery metal' to make some heli parts
> from.
> The sender told me its 6Al4V Ti, which by all accounts is a PIG to
> work
> with. However it isnt... which leads me to suspect its not Ti but a
> 7000
> series Alloy.
> Its about the same density as ally, just by hand comparisons, and its
> not
> magnetic.
> about the only simple test I can think of is to just melt an offcut
> (Ive
> already made some parts). If I can melt it before it gets red its ally
> of
> some sort, if not it might be Ti, and people are 'bigging up' how hard
> it is
> to machine....
> any other simple tests anyone can think of or comments?
>
> cheers
>
> Dave

If the density is about 2.8 g/cm^3 it's aluminium and 4.5 it's titanium. 
Easy enough to check.
-- 
Dave Baker

On Wed, 2 Jul 2008 22:45:15 +0100, "Dave Baker"  wrote:

>> any other simple tests anyone can think of or comments?
>>
>> cheers
>>
>> Dave
>
>If the density is about 2.8 g/cm^3 it's aluminium and 4.5 it's titanium. 
>Easy enough to check.

If you can set fire to it, it isn't ally but it could be Ti (or
Magnesium). But do it outside & don't try to burn it all at once...Ti
fires are just a little bit more exciting than you need in your
workshop.

Regards,
Tony

In article <g4gssv$pl9$1@news.datemas.de>, Dave Baker  
writes
>
>"dave sanderson"  wrote in message
>news:75c64664-2927-4cfd-9c0a-b33068ca11e1@a70g2000hsh.googlegroups.com...
>> Evening all,
>> I have been sent a piece of 'mystery metal' to make some heli parts
>> from.
>> The sender told me its 6Al4V Ti, which by all accounts is a PIG to
>> work
>> with. However it isnt... which leads me to suspect its not Ti but a
>> 7000
>> series Alloy.
>> Its about the same density as ally, just by hand comparisons, and its
>> not
>> magnetic.
>> about the only simple test I can think of is to just melt an offcut
>> (Ive
>> already made some parts). If I can melt it before it gets red its ally
>> of
>> some sort, if not it might be Ti, and people are 'bigging up' how hard
>> it is
>> to machine....
>> any other simple tests anyone can think of or comments?
>>
>> cheers
>>
>> Dave
>
>If the density is about 2.8 g/cm^3 it's aluminium and 4.5 it's titanium.
>Easy enough to check.

Yes, but which Ti alloy? There are hundreds. Without some testing gear 
(UTS, young's modulus, or chemical analysis) you will not find it easy 
to tell. 6-4 Ti is not that hard to machine provided your tool is dead 
sharp. Once the tool goes slightly blunt it will go to hell very 
quickly. Nothing like Al (or any Al alloy I've come across) though.

BTW, to distinguish Ti from Al, all the 6-4 Ti I have (it's all sheet 
material) is noticeably yellow and dull compared with Al. Put the two 
side by side and it's easy to see the difference.

David
-- 
David Littlewood

In article <6PA4ECO+1$aIFwdc@dlittlewood.co.uk>, David Littlewood 
 writes
>
>BTW, to distinguish Ti from Al, all the 6-4 Ti I have (it's all sheet 
>material) is noticeably yellow and dull compared with Al. Put the two 
>side by side and it's easy to see the difference.
>
An afterthought: Take a piece of EN1A and try scratching the metal. The 
pieces of Al alloy I tried it on scratched easily; the 6-4 Ti showed 
some superficial marking of the surface oxide layer, but no scratching. 
No need to make the EN1A into a point - the sharp edge of a turned bar 
offcut is sufficient.

David
-- 
David Littlewood

On 2 Jul, 22:36, dave sanderson 
wrote:
> Evening all,
> I have been sent a piece of 'mystery metal' to make some heli parts
> from.
> The sender told me its 6Al4V Ti, which by all accounts is a PIG to
> work
> with. However it isnt... which leads me to suspect its not Ti but a
> 7000
> series Alloy.
> Its about the same density as ally, just by hand comparisons, and its
> not
> magnetic.
> about the only simple test I can think of is to just melt an offcut
> (Ive
> already made some parts). If I can melt it before it gets red its ally
> of
> some sort, if not it might be Ti, and people are 'bigging up' how hard
> it is
> to machine....
> any other simple tests anyone can think of or comments?
>
> cheers
>
> Dave

So you were told it is Titanium with 6%Al and 4%Vanadium (apparently a
common grade) - but it isn't a pig to work so you suspect a duff
batch. This is not my strong suit, so let me check..

Density seems a good test. If it is the good stuff it should be about
4.4 Tonnes/cubic meter, or kg/litre, or g/cc
UTS is 1000 annealed to 1172 Prec hardened MPa so tough as old boots
all round

Dural (like 2024) is 2.8 Tonnes/m3
UTS is 186MPa annealed, 500Mpa hardened, so soft TI6AL4V is twice as
tough minimum

So am I right in thinking that the TI alloy is about 30% more dense,
but more than double the strength, so you end up with lighter
components to take the required load ?

Apart from density, a hardness test should give it away as that is
closely related to UTS - but I expect a seasoned expert working with
these alloys could tell just by a twat from an 'ammer. The TI alloy
will probably ring - the difference between ding and donk is clearly
evident to everyone working in metals, but I am not sure why it
depends on the hardness as the elastic modulus and hence the resonant
frequency should not be significantly different.

I'll leave that to one of the others to explain.

Steve

dave sanderson wrote:
> Evening all,
> I have been sent a piece of 'mystery metal' to make some heli parts
> from.
> The sender told me its 6Al4V Ti, which by all accounts is a PIG to
> work
> with. However it isnt... which leads me to suspect its not Ti but a
> 7000
> series Alloy.
> Its about the same density as ally, just by hand comparisons, and its
> not
> magnetic.
> about the only simple test I can think of is to just melt an offcut
> (Ive
> already made some parts). If I can melt it before it gets red its ally
> of
> some sort, if not it might be Ti, and people are 'bigging up' how hard
> it is
> to machine....
> any other simple tests anyone can think of or comments?
> 
> cheers
> 
> Dave

  Whack an edge against a grinder wheel, and watch for the bright white 
sparks of Ti. Or not.

  Ti. is not too tough to machine, unless the tool rubs, then it's a 
mother#$%^&**$ !! Usually, if you hear a tool squeak, it's too late 
already. :-)

  Cheers
   Trev

On Jul 2, 10:57 pm, Tony Jeffree  wrote:
> On Wed, 2 Jul 2008 22:45:15 퍝, "Dave Baker"  wrote:
> >> any other simple tests anyone can think of or comments?
>
> >> cheers
>
> >> Dave
>
> >If the density is about 2.8 g/cm^3 it's aluminium and 4.5 it's titanium.
> >Easy enough to check.
>
> If you can set fire to it, it isn't ally but it could be Ti (or
> Magnesium). But do it outside & don't try to burn it all at once...Ti
> fires are just a little bit more exciting than you need in your
> workshop.
>
> Regards,
> Tony

I have some small swarf. Ill try burning that.
the density one is possible if I had an accurate enough scale, the
alloy prototypes weigh under 0.4g...

Dave

On Jul 2, 11:13 pm, David Littlewood  wrote:
> In article <g4gssv$pl...@news.datemas.de>, Dave Baker 
> writes
>
>
>
>
>
>
>
> >"dave sanderson"  wrote in message
> >news:75c64664-2927-4cfd-9c0a-b33068ca11e1@a70g2000hsh.googlegroups.com..> >> Evening all,
> >> I have been sent a piece of 'mystery metal' to make some heli parts
> >> from.
> >> The sender told me its 6Al4V Ti, which by all accounts is a PIG to
> >> work
> >> with. However it isnt... which leads me to suspect its not Ti but a
> >> 7000
> >> series Alloy.
> >> Its about the same density as ally, just by hand comparisons, and its
> >> not
> >> magnetic.
> >> about the only simple test I can think of is to just melt an offcut
> >> (Ive
> >> already made some parts). If I can melt it before it gets red its ally
> >> of
> >> some sort, if not it might be Ti, and people are 'bigging up' how hard
> >> it is
> >> to machine....
> >> any other simple tests anyone can think of or comments?
>
> >> cheers
>
> >> Dave
>
> >If the density is about 2.8 g/cm^3 it's aluminium and 4.5 it's titanium.
> >Easy enough to check.
>
> Yes, but which Ti alloy? There are hundreds. Without some testing gear
> (UTS, young's modulus, or chemical analysis) you will not find it easy
> to tell. 6-4 Ti is not that hard to machine provided your tool is dead
> sharp. Once the tool goes slightly blunt it will go to hell very
> quickly. Nothing like Al (or any Al alloy I've come across) though.
>
> BTW, to distinguish Ti from Al, all the 6-4 Ti I have (it's all sheet
> material) is noticeably yellow and dull compared with Al. Put the two
> side by side and it's easy to see the difference.
>
> David
> --
> David Littlewood- Hide quoted text -
>
> - Show quoted text -

As it happens the actual alloy is unimportant for this application,
all the Ti's have better UTS than alloy as far as I can tell. The
part is marginal because its a stupid design, not because its alloy.
I thought Ti would be cool to make them from, and was sent this
piece of metal to try.

Dave

On Jul 3, 1:54 am, Trevor Jones  wrote:
> dave sanderson wrote:
> > Evening all,
> > I have been sent a piece of 'mystery metal' to make some heli parts
> > from.
> > The sender told me its 6Al4V Ti, which by all accounts is a PIG to
> > work
> > with. However it isnt... which leads me to suspect its not Ti but a
> > 7000
> > series Alloy.
> > Its about the same density as ally, just by hand comparisons, and its
> > not
> > magnetic.
> > about the only simple test I can think of is to just melt an offcut
> > (Ive
> > already made some parts). If I can melt it before it gets red its ally
> > of
> > some sort, if not it might be Ti, and people are 'bigging up' how hard
> > it is
> > to machine....
> > any other simple tests anyone can think of or comments?
>
> > cheers
>
> > Dave
>
>   Whack an edge against a grinder wheel, and watch for the bright white
> sparks of Ti. Or not.
>
>   Ti. is not too tough to machine, unless the tool rubs, then it's a
> mother#$%^&**$ !! Usually, if you hear a tool squeak, it's too late
> already. :-)
>
>   Cheers
>    Trev- Hide quoted text -
>
> - Show quoted text -

Now that sounds like a good 2 second test :)

Dave

On Thu, 03 Jul 2008 00:54:54 GMT, Trevor Jones 
wrote:

>Ti. is not too tough to machine, unless the tool rubs, then it's a 
>mother#$%^&**$ !! Usually, if you hear a tool squeak, it's too late 
>already. :-)

Yep - I was trying to drill a 1mm hole in a piece of Ti sheet the
other day. Combination of way too slow a speed and a slightly dull
drill - just didn't even scratch the surface.

Regards,
Tony

On 3 Jul, 08:38, dave sanderson 
wrote:
> On Jul 3, 1:54 am, Trevor Jones  wrote:
>
>
>
> > dave sanderson wrote:
> > > Evening all,
> > > I have been sent a piece of 'mystery metal' to make some heli parts
> > > from.
> > > The sender told me its 6Al4V Ti, which by all accounts is a PIG to
> > > work
> > > with. However it isnt... which leads me to suspect its not Ti but a
> > > 7000
> > > series Alloy.
> > > Its about the same density as ally, just by hand comparisons, and its
> > > not
> > > magnetic.
> > > about the only simple test I can think of is to just melt an offcut
> > > (Ive
> > > already made some parts). If I can melt it before it gets red its ally
> > > of
> > > some sort, if not it might be Ti, and people are 'bigging up' how hard
> > > it is
> > > to machine....
> > > any other simple tests anyone can think of or comments?
>
> > > cheers
>
> > > Dave
>
> >   Whack an edge against a grinder wheel, and watch for the bright white
> > sparks of Ti. Or not.
>
>
> > - Show quoted text -
>
> Now that sounds like a good 2 second test :)
>
> Dave

Its not Ti, or any other metal which sparks. no sparks at all, got to
be
alloy of some type.
Thanks all

Dave

dave sanderson wrote:
> On Jul 3, 1:54 am, Trevor Jones  wrote:
> 
>>dave sanderson wrote:
>>
>>>Evening all,
>>>I have been sent a piece of 'mystery metal' to make some heli parts
>>>from.
>>>The sender told me its 6Al4V Ti, which by all accounts is a PIG to
>>>work
>>>with. However it isnt... which leads me to suspect its not Ti but a
>>>7000
>>>series Alloy.
>>>Its about the same density as ally, just by hand comparisons, and its
>>>not
>>>magnetic.
>>>about the only simple test I can think of is to just melt an offcut
>>>(Ive
>>>already made some parts). If I can melt it before it gets red its ally
>>>of
>>>some sort, if not it might be Ti, and people are 'bigging up' how hard
>>>it is
>>>to machine....
>>>any other simple tests anyone can think of or comments?
>>
>>>cheers
>>
>>>Dave
>>
>>  Whack an edge against a grinder wheel, and watch for the bright white
>>sparks of Ti. Or not.
>>
>>  Ti. is not too tough to machine, unless the tool rubs, then it's a
>>mother#$%^&**$ !! Usually, if you hear a tool squeak, it's too late
>>already. :-)
>>
>>  Cheers
>>   Trev- Hide quoted text -
>>
>>- Show quoted text -
> 
> 
> Now that sounds like a good 2 second test :)
> 
> Dave

  Standard one in our shop.

  The sparks from Ti. are pretty bright.

  And there's almost always a grinder about the place...

  Cheers
   Trev

Tony Jeffree wrote:

> On Thu, 03 Jul 2008 00:54:54 GMT, Trevor Jones 
> wrote:
> 
> 
>>Ti. is not too tough to machine, unless the tool rubs, then it's a 
>>mother#$%^&**$ !! Usually, if you hear a tool squeak, it's too late 
>>already. :-)
> 
> 
> Yep - I was trying to drill a 1mm hole in a piece of Ti sheet the
> other day. Combination of way too slow a speed and a slightly dull
> drill - just didn't even scratch the surface.
> 
> Regards,
> Tony

  We go through a lot of $30 or so per piece,  solid carbide drill bits, 
drilling Ti. fasteners out, when they have galled into the Ti. nut, or 
have beem stripped.

  Seems expensive, until you shop the price of replacement parts that 
can't be got anywhere at all.

  Gotta be deadly sharp, gotta keep the pressure firm, steady, and 
straight, and the rpm's can run anywhere from slow to medium, relative 
to the drill size.

  A guy with a shaky hand, or with too much caution in him, will destroy 
a LOT of carbide drill bits in a day.

  Cheers
   Trevor Jones