ASTM A182 F22 Quench Properties 1

[QualityConsultant]

I have some pieces of F22 that were quenched and tempered. Our customer needs to know how deep the quench properties extend, as he intends to machine off some of the material.

Critical Diameter analysis is not appropriate because some of the elemental percentages are outside the ranges evaluated by Grossman.

Is there a method, spec, link, or something to determine how much drop in hardness to expect as material is removed?

Thank you so much for any help you can provide.

 

[metengr]

QualityConsultant;
I would suggest you contact one or more plate mills (Mittal or Sumitomo) and discuss the hardenability issue with them. I have seen information from the above companies indicating compliance of stated minimum mechanical properties for up to 12" in plate thickness for Q&T heat treatment.

 

[Metalmeister]

QC,

You and your customer are wise to recognize that through thickness properties of a Q&T material are not uniform. There are too many variables involved to make any kind of accurate prediction, and I'm pretty sure no design Code would accept such a justification.

The material specification establishes a 1/4 T location for mechanical testing. Unless the piece through hardens during the quench, the center of the bar is softer/weaker than the 1/4 T location. Depending on many variables, the center of the bar might still meet spec strength requirements for the 1/4 T location.

Do a hardness traverse of a cross section. If the center of the piece is the same hardness/strength as the 1/4 location, or if the center hardness/strength meets or exceeds F22 specification requirements for the 1/4 T location, I would feel safe to use the product for commercial application with no limits on how much the customer wants to machine off.