Castings-Critically stressed areas? 2

[cougfan]

What does it mean when a casting has a critically stressed area?

 

[metengr]

My interpretation of this statement is a location of stress concentration in the casting that could result in either local permanent deformation or fracture.

 

[cougfan]

If I am machining a part made from a casting and the drawing indicates a critically stressed area then I might observe caution? Is the critically stressed area do to un-equal cooling rates?

 

[metengr]

Does the fabrication drawing have specific requirements listed under notes or some other reference regarding surface finish or contour for this critically stressed area? I would use caution, and find out exactly what the requirements are for this location.

My sense is that you might be fabricating this part from an out-dated drawing? If so, you might be forced to interpret this statement on your own. I don't believe that it relates to un-equal cooling rates from the casting process.

 

[israelkk]

See for example MIL-STD-1265 which is avaiable at

http://assist.daps.dla.mil/quicksearch/

. There casting are divided to classes and grades where some of them for critical applications

 

[metengr]

One other thought that I had was that the critically stressed area of the casting may have been specified, by the designer, for local volumetric (RT) and surface nondestructive testing.