Torque specifications for castings
Torque specifications for castings
(OP)
I have a 7/16 Grade 8 standard steel bolt with a tensile strength of 150,000 psi which threads into a casting made of either:
Ductile iron type 65-42-12 -> tensile strength = 65,000 psi
Gray iron type G4000 -> tensile strength = 40,000 psi
I am looking for the torque specs of both castings for a 7/16 bolt and additional standard sizes. Any feedback would be appreciated.
Ductile iron type 65-42-12 -> tensile strength = 65,000 psi
Gray iron type G4000 -> tensile strength = 40,000 psi
I am looking for the torque specs of both castings for a 7/16 bolt and additional standard sizes. Any feedback would be appreciated.





RE: Torque specifications for castings
How deep can your tapped holes go?
JHG
RE: Torque specifications for castings
You can calculate a torque specification using this: FAQ725-536: How do I calculate an assembly torque?
You can calculate the required axial thread engagement using this: thread725-35222: Tensile capacity/minimum engagement
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Torque specifications for castings
RE: Torque specifications for castings
Calculate the loads on the joint and determine what fastener clamping load you need.
Determine how much variation in that load your assembly can tolerate.
Iteratively, select fastener size and number such that you properly make use of the fastener's design strength while not exceeding the pull-out strength of the casting.
Calculate the nominal fastener torque necessary to achieve the preload determined above.
Calculate the possible variation in preload that torque control will give and compare to the allowable variation determined above. Decide if torque control is sufficient for the application, or select a better method of preload control.
RE: Torque specifications for castings
RE: Torque specifications for castings
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Torque specifications for castings
Don't use rules of thumb in place of proper engineering.
RE: Torque specifications for castings
RE: Torque specifications for castings
JHG
RE: Torque specifications for castings
RE: Torque specifications for castings
If you are just looking for a simple calculator that doesn't involve detailed engineering, try the bolt torque calculator here:
http://www.futek.com/boltcalc.aspx
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Torque specifications for castings
G4000 gray iron casting with a tensile strength of 40 ksi
65-45-12 ductile iron casting with a tensile strength of 65 ksi
RE: Torque specifications for castings
The 45 in the ductile iron is the yield strength - 45 ksi.
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.