Re: actual ultimate tensile strength of cast irons...

On Wed, 12 Mar 2008 21:32:59 -0700 (PDT), hacdunqh <hacdunqh@xxxxxxxxxxx> wrote:

Does anyone have any actual data on tensile pulls of various cast
irons: soft cast, ductile, GM238,241,245,338(D6510)? Can find minimum
tensile strength, but would like actual pulls numbers. Want to make
sure that a chip shears off when machining.

"tensile pulls"?

How about using the Merchant model?
ftp://www.graco.unb.br/pub/alvares/usinagem2/merchant.html

http://www.me.umn.edu/education/courses/me3221-sum/Overviews/Machining/modeling.html

http://www.google.com/search?hl=en&safe=off&ie=ISO-8859-1&q=%22shear+zone%22+%22chip+formation%22+%22shear+angle%22+Merchant+&btnG=Search


Generally you can calculate the length of the shear zone (tool/work
interface length at the shear zone) and multiply that by the ultimate tensile
strength then multiply by the length of the shear zone along the shear angle
for the specific material and tool rake geometry to get pretty close.
This force is out on a "torque arm" though so you have to have enough
torque to generate that needed force there.
Once this force is exceeded the chip shears. You can go *faster* & use
more HP .... but the shearing force force will be pretty constant (all else
being equal).
Then you need a bit more force & energy to bend the chips, frictional
losses, etc.

For specific materials some good data can often be found at
http://www.matweb.com/ ... use the search function & you can try
the same materials under different standards if you don't find it under
your "name" for the material ... or you can search by composition.
--
Cliff
.

Relevant Pages

  • Re: Measuring Tensile strength [How do you do it at home ?]
    ... > So I have an ingot of unknown metal, how would I measure the tensile, ... > stress and strain strengths? ...
    (sci.materials)
  • Measuring Tensile strength [How do you do it at home ?]
    ... So I have an ingot of unknown metal, how would I measure the tensile, shear, ... stress and strain strengths? ...
    (sci.materials)
  • Re: Shear Strength
    ... Materials Failure Analysis", Pergamon Press, Oxford 1993 under the ... stress in shear is approximately 5/8 of the tensile strength. ... called 'complex stresses' the principle stresses set up complementary ... stress always resulted in a stress of a given degree of the applied stress. ...
    (sci.engr.metallurgy)